Penetrant testing of welded joints is used to identify external (surface and through) and. This method of testing allows you to identify defects such as hot and incomplete cooking, pores, cavities and some others.
Using penetrant flaw detection, it is possible to determine the location and size of the defect, as well as its orientation along the metal surface. This method applies to both . It is also used in welding plastics, glass, ceramics and other materials.
The essence of the capillary testing method is the ability of special indicator liquids to penetrate into the cavities of seam defects. By filling defects, indicator liquids form indicator traces, which are recorded during visual inspection or using a transducer. The procedure for penetrant control is determined by standards such as GOST 18442 and EN 1289.
Penetrant testing methods are divided into basic and combined. The main ones involve only capillary control with penetrating substances. Combined ones are based on the combined use of two or more, one of which is capillary control.
The main control methods are divided into:
Combined methods are divided depending on the nature and method of exposure to the surface being tested. And they happen:
Before performing penetrant testing, the surface to be tested must be cleaned and dried. After this, an indicator liquid - panetrant - is applied to the surface. This liquid penetrates into the surface defects of the seams and after some time, intermediate cleaning is carried out, during which excess indicator liquid is removed. Next, a developer is applied to the surface, which begins to draw the indicator liquid from the weld defects. Thus, defect patterns appear on the controlled surface, visible to the naked eye, or with the help of special developers.
The control process using the capillary method can be divided into the following stages:
The list of necessary materials for carrying out penetrant flaw detection is given in the table:
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Indicator liquid |
Intermediate cleaner |
Developer |
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Fluorescent liquids Colored liquids Fluorescent colored liquids |
Dry developer |
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Emulsifier on oil based |
Water-based liquid developer |
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Soluble Liquid Cleaner |
Aqueous developer in the form of a suspension |
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Water sensitive emulsifier |
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Water or solvent |
Liquid developer based on water or solvent for special applications |
If necessary, contaminants such as scale, rust, oil stains, paint, etc. are removed from the controlled surface of the weld. These contaminants are removed using mechanical or chemical cleaning, or a combination of these methods.
Mechanical cleaning is recommended only in exceptional cases, if there is a loose film of oxides on the controlled surface or there are sharp differences between the weld beads or deep undercuts. Mechanical cleaning has received limited use due to the fact that when it is carried out, surface defects are often closed as a result of rubbing, and they are not detected during inspection.
Chemical cleaning involves the use of various chemical cleaning agents that remove contaminants such as paint, oil stains, etc. from the surface being tested. Residues of chemical reagents can react with indicator liquids and affect the accuracy of control. That's why chemical substances after preliminary cleaning, they should be washed off the surface with water or other means.
After preliminary cleaning of the surface, it must be dried. Drying is necessary to ensure that no water, solvent, or any other substances remain on the outer surface of the seam being tested.
The application of indicator liquids to the controlled surface can be carried out in the following ways:
For better penetration indicator liquid in the defect cavity, the surface temperature should be in the range of 10-50°C.
Substances for intermediate surface cleaning should be applied in such a way that the indicator liquid is not removed from surface defects.
Excess indicator liquid can be removed by spraying or wiping with a damp cloth. At the same time, mechanical impact on the controlled surface should be avoided. The water temperature should not exceed 50°C.
First, remove excess liquid using a clean, lint-free cloth. After this, the surface is cleaned with a cloth moistened with a solvent.
Water-sensitive emulsifiers or oil-based emulsifiers are used to remove indicator liquids. Before applying the emulsifier, it is necessary to wash off excess indicator liquid with water and immediately apply the emulsifier. After emulsification, it is necessary to rinse the metal surface with water.
With this cleaning method, excess indicator liquid is first washed off from the monitored surface with water, and then the surface is cleaned with a lint-free cloth moistened with a solvent.
To dry the surface after intermediate cleaning, you can use several methods:
The drying process must be carried out in such a way that the indicator liquid does not dry out in the cavities of the defects. To do this, drying is performed at a temperature not exceeding 50°C.
The developer is applied to the controlled surface in an even thin layer. The development process should begin as soon as possible after intermediate cleaning.
The use of dry developer is only possible with fluorescent indicator liquids. The dry developer is applied by spraying or electrostatic spraying. The controlled areas should be covered uniformly and uniformly. Local accumulations of developer are unacceptable.
The developer is applied uniformly by immersing the controlled compound in it or by spraying it using a machine. When using the immersion method, to obtain the best results, the duration of the immersion should be as short as possible. The compound to be tested must then be evaporated or blast dried in an oven.
The developer is sprayed onto the controlled surface so that the surface is evenly wetted and a thin and uniform film is formed on it.
Uniform application of such a developer is achieved by immersing the controlled surfaces in it, or by spraying with special devices. The immersion should be short-term; in this case, the best test results are achieved. After this, the controlled surfaces are dried by evaporation or blowing in an oven.
The duration of the development process lasts, as a rule, for 10-30 minutes. In some cases, an increase in the duration of manifestation is allowed. The development time countdown begins: for dry developer immediately after its application, and for liquid developer - immediately after drying the surface.
If possible, inspection of the controlled surface begins immediately after applying the developer or after drying it. But the final control occurs after the development process is completed. Magnifying glasses or glasses with magnifying lenses are used as auxiliary devices for optical inspection.
The use of photochromatic glasses is not permitted. It is necessary for the inspector's eyes to adapt to the darkness in the test booth for a minimum of 5 minutes.
Ultraviolet radiation should not reach the inspector's eyes. All monitored surfaces must not fluoresce (reflect light). Also, objects that reflect light under the influence of ultraviolet rays should not fall into the controller’s field of view. General ultraviolet lighting may be used to allow the inspector to move around the test chamber without obstruction.
All controlled surfaces are inspected in daylight or artificial light. The illumination on the surface being tested must be at least 500 lux. At the same time, there should be no glare on the surface due to light reflection.
If there is a need for re-inspection, then the entire penetrant flaw detection process is repeated, starting with the pre-cleaning process. To do this, it is necessary, if possible, to provide more favorable conditions control.
For repeated control, it is allowed to use only the same indicator liquids, from the same manufacturer, as during the first control. The use of other liquids, or the same liquids from different manufacturers, is not permitted. In this case, it is necessary to thoroughly clean the surface so that no traces of the previous inspection remain on it.
According to EN571-1, the main stages of penetrant testing are presented in the diagram:
NON-DESTRUCTIVE TESTING
Color method of inspection of joints, deposited and base metal
|
General Director of OJSC "VNIIPTkhimnefteapparatura" |
V.A. Panov |
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Head of Standardization Department |
V.N. Zarutsky |
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Head of Department No. 29 |
S.Ya. Luchin |
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Head of Laboratory No. 56 |
L.V. Ovcharenko |
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Development Manager, Senior Researcher |
V.P. Novikov |
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Lead Engineer |
L.P. Gorbatenko |
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Technological engineer II category. |
N.K. Lamina |
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Standardization engineer Cat. I |
BEHIND. Lukina |
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Co-executor Head of Department of OJSC "NIIKHIMMASH" |
N.V. Khimchenko |
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AGREED Deputy General Director |
V.V. Rakov |
Preface
1. DEVELOPED by JSC Volgograd Research and Design Institute of Chemical and Petroleum Equipment Technology (JSC VNIIPT Chemical and Petroleum Equipment)
2. APPROVED AND PUT INTO EFFECT by Technical Committee No. 260 “Chemical and oil and gas processing equipment” with an Approval Sheet dated December 1999.
3. AGREED by letter of the State Mining and Technical Supervision of Russia No. 12-42/344 dated 04/05/2001.
4. INSTEAD OF OST 26-5-88
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1 area of use. 2 3 General provisions. 2 4 Requirements for the inspection area using the color method.. 3 4.1 General requirements. 3 4.2 Requirements for the color control workplace.. 3 5 Flaw detection materials.. 4 6 Preparation for color control.. 5 7 Methodology of control. 6 7.1 Application of indicator penetrant. 6 7.2 Removal of indicator penetrant. 6 7.3 Application and drying of developer. 6 7.4 Inspection of the controlled surface. 6 8 Assessment of surface quality and recording of control results. 6 9 Safety requirements. 7 Appendix A. Roughness standards for the controlled surface. 8 Appendix B. Maintenance standards for color inspection.. 9 Appendix B. Illumination values of the controlled surface. 9 Appendix D. Control samples for checking the quality of flaw detection materials. 9 Appendix E. List of reagents and materials used for color control.. 11 Appendix E. Preparation and rules for using flaw detection materials. 12 Appendix G. Storage and quality control of flaw detection materials. 14 Appendix I. Consumption rates for flaw detection materials. 14 Appendix K. Methods for assessing the quality of degreasing of a controlled surface. 15 Appendix L. Color control log form.. 15 Appendix M. Form of conclusion based on the results of control using the color method.. 15 Appendix H. Examples of abbreviated recording of color control.. 16 Appendix P. Certificate for the control sample. 16 |
OST 26-5-99
INDUSTRY STANDARD
Date of introduction 2000-04-01
This standard applies to the color inspection method of welded joints, deposited and base metal of all grades of steel, titanium, copper, aluminum and their alloys.
The standard is valid in the chemical, oil and gas engineering industry and can be used for any objects controlled by the State Technical Supervision Authority of Russia.
The standard establishes requirements for the methodology for preparing and conducting inspection using the color method, inspected objects (vessels, apparatus, pipelines, metal structures, their elements, etc.), personnel and workplaces, flaw detection materials, evaluation and recording of results, as well as safety requirements.
GOST 12.0.004-90 SSBT Organization of occupational safety training for workers
GOST 12.1.004-91 SSBT. Fire safety. General requirements
GOST 12.1.005-88 SSBT. General sanitary and hygienic requirements for the air in the working area
PPB 01-93 Rules fire safety In Russian federation
Rules for certification of non-destructive testing specialists, approved by Gosgortekhnadzor of Russia
RD 09-250-98 Regulations on the procedure for safe carrying out repair work at chemical, petrochemical and oil refining hazardous production facilities, approved by the Gosgortekhnadzor of Russia
RD 26-11-01-85 Instructions for testing welded joints that are not accessible for radiographic and ultrasonic testing
SN 245-71 Sanitary standards for the design of industrial enterprises
Standard instructions for carrying out gas-hazardous work, approved by the USSR State Mining and Technical Supervision Authority on February 20, 1985.
3.1 Color non-destructive testing method (color flaw detection) refers to capillary methods and is intended to identify defects such as discontinuities that appear on the surface.
3.2 The use of the color method, the scope of inspection, and the class of defects are established by the developer of the design documentation for the product and reflected in technical requirements drawing.
3.3 The required sensitivity class of color testing according to GOST 18442 is ensured by the use of appropriate flaw detection materials while meeting the requirements of this standard.
3.4 Inspection of objects made of non-ferrous metals and alloys must be carried out before their mechanical processing.
3.5 Inspection by the color method should be carried out before applying paint and varnish and other coatings or after their complete removal from the controlled surfaces.
3.6 When inspecting an object using two methods - ultrasonic and color, inspection by the color method should be carried out before ultrasonic.
3.7 The surface to be inspected by the color method must be cleaned of metal splashes, soot, scale, slag, rust, various organic substances (oils, etc.) and other contaminants.
In the presence of metal splashes, soot, scale, slag, rust, etc. If the surface becomes contaminated, it must be mechanically cleaned.
Mechanical cleaning of surfaces made of carbon, low-alloy steels, and similar mechanical properties should be carried out grinder with electrocorundum grinding wheel on a ceramic bond.
It is allowed to clean the surface with metal brushes, abrasive paper or other methods in accordance with GOST 18442, ensuring compliance with the requirements of Appendix A.
It is recommended to clean the surface from grease and other organic contaminants, as well as from water, by heating the surface or objects, if the objects are small, for 40 - 60 minutes at a temperature of 100 - 120 ° C.
Note. Mechanical cleaning and heating of the controlled surface, as well as cleaning the object after testing are not the duties of the flaw detector.
3.8 The roughness of the tested surface must comply with the requirements of Appendix A of this standard and be indicated in the regulatory and technical documentation for the product.
3.9 The surface subject to color inspection must be accepted by the quality control service based on the results of visual inspection.
3.10 In welded joints, the surface of the weld and adjacent areas of the base metal with a width of at least the thickness of the base metal, but not less than 25 mm on both sides of the seam for a metal thickness of up to 25 inclusive, and 50 mm for a metal thickness of over 25 are subject to color inspection mm to 50 mm.
3.11 Welded joints with a length of more than 900 mm should be divided into control sections (zones), the length or area of which should be set so as to prevent the indicator penetrant from drying out before it is re-applied.
For circumferential welded joints and welded edges, the length of the controlled section should be the same as the diameter of the product:
up to 900 mm - no more than 500 mm,
over 900 mm - no more than 700 mm.
The area of the controlled surface should not exceed 0.6 m2.
3.12 When checking the inner surface of a cylindrical vessel, its axis should be inclined at an angle of 3 - 5° to the horizontal, ensuring the drainage of waste liquids.
3.13 Inspection by the color method should be carried out at a temperature from 5 to 40 °C and a relative humidity of no more than 80%.
It is allowed to carry out control at temperatures below 5 °C using appropriate flaw detection materials.
3.14 Carrying out inspection using the color method during installation, repair or technical diagnostics objects should be registered as gas hazardous work in accordance with RD 09-250.
3.15 Inspection by the color method must be carried out by persons who have undergone special theoretical and practical training and are certified in the prescribed manner in accordance with the “Rules for Certification of Non-Destructive Testing Specialists”, approved by the State Technical Supervision Authority of Russia, and who have the appropriate certificates.
3.16 Maintenance standards for color inspection are given in Appendix B.
3.17 This standard can be used by enterprises (organizations) when developing technological instructions and (or) other technological documentation for color control for specific objects.
4.1.1 The control area using the color method should be located in dry, heated, isolated rooms with natural and (or) artificial lighting and supply exhaust ventilation in accordance with the requirements of CH-245, GOST 12.1.005 and 3.13, 4.1.4, 4.2.1 of this standard, away from high-temperature sources and mechanisms that cause sparking.
Supply air with a temperature below 5 °C should be heated.
4.1.2 When using flaw detection materials using organic solvents and other fire and explosive substances, the control area must be located in two adjacent rooms.
In the first room, technological operations of preparation and control, as well as inspection of controlled objects, are performed.
The second room contains heating devices and equipment on which work is performed that does not involve the use of fire and explosive substances and which, according to safety regulations, cannot be installed in the first room.
It is allowed to carry out inspection using the color method at production (installation) sites in full compliance with the inspection methodology and safety requirements.
4.1.3 In the area for monitoring large-sized objects, if the permissible vapor concentration of the used flaw detection materials is exceeded, stationary suction panels, portable exhaust hoods or suspended exhaust panels mounted on a rotating single- or double-hinged suspension.
Portable and suspended suction devices must be connected to the ventilation system by flexible air ducts.
4.1.4 Color lighting at the inspection site must be combined (general and local).
It is allowed to use one general lighting if the use of local lighting is impossible due to production conditions.
The lamps used must be explosion-proof.
Illumination values are given in Appendix B.
Using optical instruments and other means for inspecting the controlled surface, its illumination must comply with the requirements of the documents for the operation of these devices and (or) means.
4.1.5 The inspection area using the color method must be provided with dry, clean compressed air at a pressure of 0.5 - 0.6 MPa.
Compressed air must enter the area through a moisture-oil separator.
4.1.6 The site must have a cold and hot water with drainage into the sewer.
4.1.7 The floor and walls in the site premises must be covered with easily washable materials (metlakh tiles, etc.).
4.1.8 Cabinets for storing tools, devices, flaw detection and auxiliary materials, and documentation must be installed on the site.
4.1.9 The composition and placement of equipment in the color control area must ensure the technological sequence of operations and comply with the requirements of Section 9.
4.2.1 Workplace for control the following must be equipped:
supply and exhaust ventilation and local exhaust with at least three air exchanges (an exhaust hood must be installed above the workplace);
a lamp for local lighting, providing illumination in accordance with Appendix B;
source of compressed air with an air reducer;
a heater (air, infrared or other type) that ensures drying of the developer at a temperature below 5 °C.
4.2.2 A table (workbench) for testing small objects, as well as a table and chair with a grid for the feet of the flaw detector should be installed at the workplace.
4.2.3 The following devices, devices, instruments, appliances, flaw detection and auxiliary materials, and other accessories for performing inspection must be available at the workplace:
paint sprayers with low air consumption and low productivity (for applying indicator penetrant or spray developer);
control samples and devices (for checking the quality and sensitivity of flaw detection materials) in accordance with Appendix D;
magnifiers with 5 and 10x magnification (for general inspection of the controlled surface);
telescopic magnifying glasses (for inspection of controlled surfaces located inside the structure and remote from the eyes of the flaw detector, as well as surfaces in the form of sharp dihedral and polyhedral angles);
sets of standard and special probes (for measuring the depth of defects);
metal rulers (for determining the linear dimensions of defects and marking inspected areas);
chalk and (or) colored pencil (for marking inspected areas and marking defective areas);
sets of painting hair and bristle brushes (for degreasing the controlled surface and applying indicator penetrant and developer to it);
a set of bristle brushes (for degreasing the controlled surface if necessary);
napkins and (or) rags made of cotton fabrics of the calico group (for wiping the controlled surface. It is not allowed to use napkins or rags made of wool, silk, synthetic, or fleecy fabrics);
cleaning rags (to remove mechanical and other contaminants from the controlled surface if necessary);
filter paper (for checking the quality of degreasing the controlled surface and filtering the prepared flaw detection materials);
rubber gloves (to protect the hands of the flaw detector from materials used during inspection);
cotton robe (for a flaw detectorist);
cotton suit (for working inside the facility);
a rubberized apron with a bib (for a flaw detector operator);
rubber boots (for working inside the facility);
universal filtering respirator (for work inside the facility);
flashlight with a 3.6 W lamp (for work in installation conditions and during technical diagnostics of an object);
tightly closing, unbreakable containers (for flaw detection materials at 5
one-time work, when carrying out inspection using brushes);
laboratory scales with a scale of up to 200 g (for weighing components of flaw detection materials);
set of weights up to 200 g;
a set of flaw detection materials for testing (can be in an aerosol package or in a tightly closed unbreakable container, in quantities designed for one-shift work).
4.2.4 The list of reagents and materials used for control by the color method is given in Appendix D.
5.1 The set of flaw detection materials for inspection by the color method consists of:
indicator penetrant (I);
penetrant remover (M);
penetrant developer (P).
5.2 The choice of a set of flaw detection materials should be determined depending on the required sensitivity of the control and the conditions of its use.
Sets of flaw detection materials are listed in Table 1, the recipe, preparation technology and rules for their use are given in Appendix E, storage rules and quality control - in Appendix G, consumption rates - in Appendix I.
It is allowed to use flaw detection materials and (or) their sets not provided for by this standard, provided that the necessary control sensitivity is ensured.
Table 1 - Sets of flaw detection materials
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Industry designation of the set |
Purpose of dialing |
Dial Purpose Indicators |
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Conditions of use |
Flaw detection materials |
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Temperature °C |
application features |
penetrant |
cleaner |
developer |
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Fire hazardous, toxic |
at Ra? 6.3 µm |
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Low toxicity, fireproof, applicable in enclosed spaces requires careful cleaning of penetrant |
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For rough welds |
Fire hazardous, toxic |
at Ra? 6.3 µm |
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For layer-by-layer inspection of welds |
Fire hazardous, toxic, developer removal is not required before the next welding operation |
Liquid K |
at Ra? 6.3 µm |
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To achieve high sensitivity |
Fire hazardous, toxic, applicable to objects that exclude contact with water |
Liquid K |
Oil-kerosene mixture |
at Ra? 3.2 µm |
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(IFH-Color-4) |
Environmentally friendly and fireproof, non-corrosive, compatible with water |
According to the manufacturer's specifications |
Any according to Appendix E |
at Ra = 12.5 µm |
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For rough welds |
Aerosol method of applying penetrant and developer |
According to the manufacturer's specifications |
at Ra? 6.3 µm |
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at Ra? 3.2 µm |
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Notes: 1 The designation of the set in parentheses is given by its developer. 2 Surface roughness (Ra) - according to GOST 2789. 3 Sets DN-1Ts - DN-6Ts should be prepared according to the recipe given in Appendix E. 4 Liquid K and paint M (manufacturer Lviv paint and varnish plant), sets: DN-8Ts (manufacturer: IFH UAN, Kiev), DN-9Ts and TsAN (manufacturer: Nevinnomyssk Petroleum Chemical Plant) - are supplied ready-made. 5 Developers that can be used for these indicator penetrants are indicated in parentheses. |
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6.1 During mechanized inspection, before starting work, you should check the functionality of the mechanization means and the quality of spraying of flaw detection materials.
6.2 The sets and sensitivity of flaw detection materials must comply with the requirements of Table 1.
The sensitivity of flaw detection materials should be checked according to Appendix G.
6.3 The surface to be inspected must comply with the requirements of 3.7 - 3.9.
6.4 The surface to be tested must be degreased with an appropriate composition from a specific set of flaw detection materials.
It is allowed to use organic solvents (acetone, gasoline) for degreasing in order to achieve maximum sensitivity and (or) when carrying out control at low temperatures.
Degreasing with kerosene is not allowed.
6.5 When carrying out control in rooms without ventilation or inside an object, degreasing should be carried out with an aqueous solution of powdered synthetic detergent (CMC) of any brand with a concentration of 5%.
6.6 Degreasing should be carried out with a hard, bristle brush (brush) corresponding to the size and shape of the controlled area.
It is allowed to carry out degreasing with a napkin (rag) soaked in a degreasing composition, or by spraying a degreasing composition.
Degreasing of small objects should be done by immersing them in appropriate compounds.
6.7 After degreasing, the controlled surface must be dried with a stream of clean, dry air at a temperature of 50 - 80 °C.
It is allowed to dry the surface using dry, clean cloth napkins, followed by holding for 10 - 15 minutes.
It is recommended to dry small objects after degreasing by heating them to a temperature of 100 - 120 °C and holding them at this temperature for 40 - 60 minutes.
6.8 When carrying out testing at low temperatures, the tested surface should be degreased with gasoline and then dried with alcohol using dry, clean cloth wipes.
6.9 The surface that was etched before testing should be neutralized with an aqueous solution of soda ash with a concentration of 10 - 15%, and rinsed clean water and dry with a stream of dry, clean air at a temperature of at least 40 ° C or with dry, clean cloth wipes, and then process in accordance with 6.4 - 6.7.
6.11 The controlled surface should be marked into sections (zones) in accordance with 3.11 and marked in accordance with the control map in the manner adopted at the given enterprise.
6.12 The time interval between the completion of preparation of the object for testing and the application of indicator penetrant should not exceed 30 minutes. During this time, the possibility of condensation of atmospheric moisture on the controlled surface, as well as contact with it, must be excluded. various liquids and pollution.
7.1.1 The indicator penetrant should be applied to the surface prepared in accordance with Section 6 with a soft hair brush corresponding to the size and shape of the controlled area (zone), by spraying (paint spray, aerosol method) or dipping (for small objects).
The penetrant should be applied to the surface in 5 - 6 layers, not allowing the previous layer to dry out. The area of the last layer should be several more area previously applied layers (so that the penetrant that has dried along the contour of the stain dissolves as the last layer without leaving traces that, after applying the developer, form a pattern of false cracks).
7.1.2 When carrying out testing in low temperature conditions, the temperature of the indicator penetrant must be at least 15 °C.
7.2.1 The indicator penetrant should be removed from the controlled surface immediately after applying its last layer, with a dry, clean lint-free cloth, and then with a clean cloth soaked in a cleaner (in low temperature conditions - in technical ethyl alcohol) until the painted background is completely removed , or any other method according to GOST 18442.
With the roughness of the controlled surface Ra? The 12.5 µm background generated by penetrant residues should not exceed the background established by the control sample according to Appendix D.
The oil-kerosene mixture should be applied with a bristle brush, immediately after applying the last layer of penetrating liquid K, without allowing it to dry out, while the area covered with the mixture should be slightly larger than the area covered with penetrating liquid.
Removal of penetrating liquid with an oil-kerosene mixture from the controlled surface should be done with a dry, clean rag.
7.2.2 The controlled surface, after removing the indicator penetrant, should be dried with a dry, clean, lint-free cloth.
7.3.1 The developer must be a homogeneous mass without lumps or separations, for which it should be thoroughly mixed before use.
7.3.2 The developer should be applied to the controlled surface immediately after removing the indicator penetrant, in one thin, even layer, ensuring the detection of defects, with a soft hair brush corresponding to the size and shape of the controlled area (zone), by spraying (spray gun, aerosol) or dipping (for small objects).
It is not allowed to apply the developer to the surface twice, as well as its sagging and smudges on the surface.
When using the aerosol method of application, the valve of the spray head of the developer can should be purged with freon before use, to do this, turn the can upside down and briefly press the spray head. Then, turn the can with the spray head up and shake it for 2 - 3 minutes to mix the contents. Make sure the spray is good by pressing the spray head and directing the spray away from the object.
When atomization is satisfactory, without closing the valve of the spray head, transfer the stream of developer to the controlled surface. The spray head of the can must be located at a distance of 250 - 300 mm from the controlled surface.
It is not allowed to close the valve of the spray head when directing the jet towards the object to avoid large drops of developer from falling onto the controlled surface.
Spraying should be completed by directing the developer stream away from the object. At the end of spraying, blow the valve of the spray head again with freon.
If the spray head is clogged, it should be removed from the socket, washed in acetone and blown with compressed air (rubber bulb).
Paint M should be applied immediately after removing the oil-kerosene mixture, using a paint sprayer, to ensure the greatest sensitivity of control. The time interval between removing the oil-kerosene mixture and applying paint M should not exceed 5 minutes.
It is allowed to apply paint M with a hair brush when using a paint sprayer is not possible.
7.3.3 Drying of the developer can be carried out by natural evaporation or in a stream of clean, dry air at a temperature of 50 - 80 °C.
7.3.4 Drying the developer at low temperatures can be done with additional use reflective electric heating devices.
7.4.1 Inspection of the controlled surface should be carried out 20 - 30 minutes after the developer has dried. In cases where there is doubt when examining the controlled surface, a 5x or 10x magnification magnifying glass should be used.
7.4.2 Inspection of the controlled surface during layer-by-layer control should be carried out no later than 2 minutes after applying the organic-based developer.
7.4.3 Defects identified during the inspection should be noted in the manner accepted at the given enterprise.
8.1 Assessment of surface quality based on the results of color testing should be carried out based on the shape and size of the indicator mark pattern in accordance with the requirements of the design documentation for the facility or Table 2.
Table 2 - Standards for surface defects for welded joints and base metal
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Type of defect |
Defect class |
Material thickness, mm |
Maximum permissible linear size of the indicator trace of a defect, mm |
The maximum permissible number of defects on a standard surface area |
|
Cracks of all types and directions |
Regardless |
Not allowed |
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Individual pores and inclusions that appear in the form of round or elongated spots |
Regardless |
Not allowed |
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0.2S, but not more than 3 |
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No more than 3 |
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0.2S, but not more than 3 |
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or no more than 5 |
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No more than 3 |
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or no more than 5 |
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0.2S, but not more than 3 |
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or no more than 5 |
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No more than 3 |
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or no more than 5 |
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or no more than 9 |
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Notes: 1 In anti-corrosion surfacing of defect classes 1 - 3, defects of all types are not allowed; for class 4 - single scattered pores and slag inclusions up to 1 mm in size are allowed, no more than 4 in a standard area of 100×100 mm and no more than 8 in an area of 200×200 mm. 2 Standard section, with a metal (alloy) thickness of up to 30 mm - a weld section 100 mm long or a base metal area of 100×100 mm, with a metal thickness over 30 mm - a weld section 300 mm long or a base metal area of 300×300 mm . 3 If the thickness of the welded elements is different, determining the size of the standard section and assessing the quality of the surface should be done using the element of the smallest thickness. 4 Indicative traces of defects are divided into two groups - extended and rounded; an extended indicator trace is characterized by a length-to-width ratio greater than 2, rounded - a length-to-width ratio equal to or less than 2. 5 Defects should be defined as separate if the ratio of the distance between them to the maximum value of their indicator trace is greater than 2, while this ratio is equal to or less than 2, the defect should be defined as one. |
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8.2 The results of control should be recorded in a journal with mandatory completion of all its columns. The log form (recommended) is given in Appendix L.
The journal must have continuous page numbering, be bound and signed by the head of the non-destructive testing service. Corrections must be confirmed by the signature of the head of the non-destructive testing service.
8.3 The conclusion on the results of control should be drawn up based on the journal entry. The conclusion form (recommended) is given in Appendix M.
It is allowed to supplement the journal and conclusion with other information accepted at the enterprise.
8.5 Legend type of defects and control technology - according to GOST 18442.
Examples of recording are given in Appendix N.
9.1 Persons certified in accordance with 3.15, who have undergone special training in accordance with GOST 12.0.004 on safety rules, electrical safety (up to 1000 V), fire safety in accordance with the relevant instructions in force at this enterprise, with a record of conducting instructions in a special magazine.
9.2 Flaw detectors performing color inspection are subject to a preliminary (upon entry to work) and annual medical examination with a mandatory color vision test.
9.3 Color control work must be carried out in special clothing: a cotton robe (suit), a cotton jacket (at temperatures below 5 °C), rubber gloves, and a hat.
When using rubber gloves, hands should first be coated with talcum powder or lubricated with Vaseline.
9.4 At the inspection site using the color method, it is necessary to comply with fire safety rules in accordance with GOST 12.1.004 and PPB 01.
Smoking, open flames and any kind of sparks are not allowed at a distance of 15 m from the control point.
Posters must be posted at the work site: “Flammable”, “Do not enter with fire”.
9.6 The amount of organic liquids in the control area using the color method should be within the shift requirement, but not more than 2 liters.
9.7 Combustible substances should be stored in special metal cabinets equipped with exhaust ventilation or in hermetically sealed, unbreakable containers.
9.8 Used cleaning material (napkins, rags) must be kept in a metal, tightly closed container and periodically disposed of in the manner established by the enterprise.
9.9 Preparation, storage and transportation of flaw detection materials should be carried out in unbreakable, hermetically sealed containers.
9.10 Maximum permissible concentrations of vapors of flaw detection materials in the air of the working area - according to GOST 12.1.005.
9.11 Inspection of the internal surface of objects should be carried out with a constant supply fresh air inside the object to avoid the accumulation of vapors of organic liquids.
9.12 Inspection by the color method inside the facility must be carried out by two flaw detectors, one of whom, being outside, ensures compliance with safety requirements, maintains auxiliary equipment, maintains communication and assists the flaw detector working inside.
The time of continuous work of a flaw detector inside a facility should not exceed one hour, after which the flaw detector should replace each other.
9.13 To reduce the fatigue of flaw detectors and improve the quality of inspection, it is advisable to take a break of 10 - 15 minutes after every hour of work.
9.14 Portable lamps must be explosion-proof with a power supply voltage of no more than 12 V.
9.15 When monitoring an object installed on a roller stand, a poster “Do not turn on, people are working” should be posted on the control panel of the stand.
9.16 When working with a set of flaw detection materials in aerosol packaging, the following is not allowed: spraying the compositions near an open flame; smoking; heating the cylinder with the composition above 50 °C, placing it near a heat source and in direct sunlight, mechanical impact on the cylinder (impacts, destruction, etc.), as well as discarding until the contents are fully used; contact of the composition with the eyes.
9.17 Hands should be washed immediately after carrying out color testing warm water with soap.
Do not use kerosene, gasoline or other solvents to wash your hands.
If your hands are dry, skin softening creams should be used after washing.
Eating in the color control area is not allowed.
9.18 The color control area must be provided with fire extinguishing means in accordance with current fire safety standards and regulations.
(required)
|
Object of control |
Group of vessels, devices according to PB 10-115 |
Sensitivity class according to GOST 18442 |
Defect class |
Surface roughness according to GOST 2789, microns, no more |
Recession between weld beads, mm, no more |
|
|
Welded connections of vessel and apparatus bodies (circular, longitudinal, welding of bottoms, pipes and other elements), edges for welding |
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Technological |
Unprocessed |
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Technological surfacing of edges for welding |
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Anti-corrosion surfacing |
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Areas of other elements of vessels and devices where defects were found during visual inspection |
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Welded connections of pipelines P slave? 10 MPa |
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Welded connections of pipelines P slave< 10 МПа |
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Table B.1 - Scope of inspection for one flaw detector in one shift (480 min)
The actual value of the service norm (Nf), taking into account the location of the object and the conditions of control, is determined by the formula:
Nf = No/(Ksl?Kr?Ku?Kpz),
where No is the standard of service according to table B.1;
Ksl - complexity coefficient according to table B.2;
Kr - placement coefficient according to table B.3;
Ku - coefficient of conditions according to table B.4;
Kpz - coefficient of preparatory-final time equal to 1.15.
The complexity of monitoring 1 m of a weld or 1 m2 of surface is determined by the formula:
T = (8? Ksl? Kr? Ku? Kpz) / But
Table B.2 - Control complexity coefficient, Ksl
Table B.3 - Coefficient of placement of control objects, Kr
Table B.4 - Coefficient of control conditions, Ku
(required)
|
Sensitivity class according to GOST 18442 |
Minimum size of defect (crack) |
Illumination of the controlled surface, lux |
||
|
opening width, µm |
length, mm |
combined |
||
|
from 10 to 100 |
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from 100 to 500 |
||||
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Technological |
Not standardized |
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D.1 Control sample with an artificial defect
The sample is made of corrosion-resistant steel and is a frame with two plates placed in it, pressed together with a screw (Fig. D.1). The contact surfaces of the plates must be lapped, their roughness (Ra) is no more than 0.32 microns, the roughness of other surfaces of the plates is no more than 6.3 microns according to GOST 2789.
An artificial defect (wedge-shaped crack) is created by a probe of appropriate thickness placed between the contact surfaces of the plates on one edge.
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1 - screw; 2 - frame; 3 - plates; 4 - dipstick
a - control sample; b - plate
Figure D.1 - Control sample of two plates
D.2 Enterprise control samples
Samples can be made from any corrosion-resistant steels using methods accepted by the manufacturer.
Samples must have defects such as unbranched dead-end cracks with openings corresponding to the applied control sensitivity classes according to GOST 18442. The width of the crack opening must be measured on a metallographic microscope.
The accuracy of measuring the crack opening width, depending on the sensitivity class of the control according to GOST 18442, should be for:
Class I - up to 0.3 microns,
Classes II and III - up to 1 micron.
Control samples must be certified and subject to periodic inspection depending on production conditions, but at least once a year.
The samples must be accompanied by a passport in the form given in Appendix P with a photograph of the picture of the detected defects and an indication of the set of flaw detection materials used during the inspection. The form of the passport is recommended, but the content is mandatory. The passport is issued by the non-destructive testing service of the enterprise.
If the control sample does not correspond to the passport data as a result of long-term operation, it should be replaced with a new one.
D.3 Technology for manufacturing control samples
D.3.1 Sample No. 1
The test object is made of corrosion-resistant steel or its part with natural defects.
D.3.2 Sample No. 2
The sample is made of sheet steel grade 40X13 with dimensions 100×30×(3 - 4) mm.
The seam should be melted along the workpiece using argon arc welding without the use of filler wire in mode I = 100 A, U = 10 - 15 B.
Bend the workpiece on any device until cracks appear.
D3.3 Sample No. 3
The sample is made from sheet steel 1Х12Н2ВМФ or from any nitrided steel with dimensions of 30×70×3 mm.
Straighten the resulting workpiece and grind it to a depth of 0.1 mm on one (working) side.
The workpiece is nitrided to a depth of 0.3 mm without subsequent hardening.
Grind the working side of the workpiece to a depth of 0.02 - 0.05 mm.
1 - device; 2 - test sample; 3 - vice; 4 - punch; 5 - bracket
Figure D.2 - Device for making a sample
Surface roughness Ra should be no more than 40 microns according to GOST 2789.
Place the workpiece in the device in accordance with Figure D.2, place the device with the workpiece in a vice and smoothly clamp it until the characteristic crunch of the nitrided layer appears.
D.3.4 Control background sample
Apply a layer of developer from the used set of flaw detection materials to the metal surface and dry it.
Apply the indicator penetrant from this kit once, diluted with an appropriate cleaner 10 times, onto the dried developer and dry.
(informative)
Gasoline B-70 for industrial and technical purposes
Laboratory filter paper
Cleaning rags (sorted) cotton
Auxiliary substance OP-7 (OP-10)
Drinking water
Distilled water
Penetrating liquid red K
Kaolin enriched for cosmetic industry, grade 1
Tartaric acid
Kerosene for lighting
Paint M developing white
Fat-soluble dark red dye F (Sudan IV)
Fat-soluble dark red dye 5C
Dye "Rhodamine S"
Dye "Fuchsin sour"
Coal xylene
Transformer oil brand TK
Oil MK-8
Chemically precipitated chalk
Monoethanolamine
Sets of flaw detection materials according to Table 1, supplied ready-made
Sodium caustic technical brand A
Sodium nitrate chemically pure
Sodium phosphate trisubstituted
Sodium silicate soluble
Nefras S2-80/120, S3-80/120
Noriol grade A (B)
White soot grade BS-30 (BS-50)
Synthetic detergent (CMC) - powder, any brand
Gum turpentine
Soda ash
Rectified technical ethyl alcohol
Cotton fabrics of the calico group
E.1 Indicator penetrants
E.1.1 Penetrant I1:
fat-soluble dark red dye F (Sudan IV) - 10 g;
gum turpentine - 600 ml;
noriol grade A (B) - 10 g;
nefras C2-80/120 (C3-80/120) - 300 ml.
Dissolve dye G in a mixture of turpentine and noriol in a water bath at 50 °C for 30 minutes. constantly stirring the composition. Add nefras to the resulting composition. Allow the mixture to reach room temperature and filter.
E.1.2 Penetrant I2:
fat-soluble dark red dye F (Sudan IV) - 15 g;
gum turpentine - 200 ml;
lighting kerosene - 800 ml.
Completely dissolve dye G in turpentine, add kerosene to the resulting solution, place the container with the prepared composition in a boiling water bath and leave for 20 minutes. Filter the composition that has cooled to a temperature of 30 - 40 °C.
E.1.3 Penetrant I3:
distilled water - 750 ml;
auxiliary substance OP-7 (OP-10) - 20 g;
dye “Rhodamine S” - 25 g;
sodium nitrate - 25 g;
Rectified technical ethyl alcohol - 250 ml.
Completely dissolve the Rhodamine C dye in ethyl alcohol, constantly stirring the solution. Dissolve sodium nitrate and auxiliary substance completely in distilled water, heated to a temperature of 50 - 60 °C. Pour the resulting solutions together while constantly stirring the composition. Let the mixture stand for 4 hours and filter.
When monitoring according to sensitivity class III according to GOST 18442, it is allowed to replace “Rhodamin S” with “Rhodamin Zh” (40 g).
E.1.4 Penetrant I4:
distilled water - 1000 ml;
tartaric acid - 60 - 70 g;
dye “Fuchsin sour” - 5 - 10 g;
synthetic detergent (CMC) - 5 - 15 g.
Dissolve the “Fuchsin sour” dye, tartaric acid and synthetic detergent in distilled water, heated to a temperature of 50 - 60 °C, hold to a temperature of 25 - 30 °C and filter the composition.
E.1.5 Penetrant I5:
fat-soluble dark red dye F - 5 g;
fat-soluble dark red dye 5C - 5 g;
Coal xylene - 30 ml;
nefras C2-80/120 (C3-80/120) - 470 ml;
gum turpentine 500 ml.
Dissolve dye G in turpentine, dye 5C in a mixture of nefras and xylene, pour the resulting solutions together, mix and filter the composition.
E.1.6 Red penetrating liquid K.
Liquid K is a low-viscosity dark red liquid that does not have separation, insoluble sediment and suspended particles.
With prolonged (over 7 hours) exposure to negative temperatures (up to -30 °C and below) a sediment may appear in liquid K due to a decrease in the dissolving ability of its components. Before use, such a liquid should be kept at a positive temperature for at least 24 hours, periodically stirring or shaking until the sediment is completely dissolved, and kept for at least an additional hour.
E.2 Indicator penetrant cleaners
E.2.1 Cleaner M1:
drinking water - 1000 ml;
auxiliary substance OP-7 (OP-10) - 10 g.
Completely dissolve the auxiliary substance in water.
E.2.2 Cleaner M2: rectified technical ethyl alcohol - 1000 ml.
The cleaner should be used at low temperatures: from 8 to minus 40 °C.
E.2.3 Purifier M3: drinking water - 1000 ml; soda ash - 50 g.
Dissolve soda in water at a temperature of 40 - 50 °C.
The cleaner should be used for control in rooms with a high fire hazard and (or) small in volume, without ventilation, as well as inside objects.
B.2.4 Oil-kerosene mixture:
lighting kerosene - 300 ml;
transformer oil (MK-8 oil) - 700 ml.
Mix transformer oil (MK-8 oil) with kerosene.
It is allowed to deviate from the nominal oil volume in the direction of decrease by no more than 2%, and in the direction of increase - by no more than 5%.
The mixture should be mixed thoroughly before use.
E.3 Indicator penetrant developers
E.3.1 Developer P1:
distilled water - 600 ml;
enriched kaolin - 250 g;
Rectified technical ethyl alcohol - 400 ml.
Add kaolin to a mixture of water and alcohol and mix until a homogeneous mass is obtained.
E.3.2 Developer P2:
enriched kaolin - 250 (350) g;
Rectified technical ethyl alcohol - 1000 ml.
Mix kaolin with alcohol until smooth.
Notes:
1 When applying the developer with a paint sprayer, 250 g of kaolin should be added to the mixture, and when applying with a brush - 350 g.
2 Developer P2 can be used at a temperature of the controlled surface from 40 to -40 °C.
It is allowed to use chemically precipitated chalk or chalk-based tooth powder instead of kaolin in the P1 and P2 developers.
E.3.3 Developer P3:
drinking water - 1000 ml;
chemically precipitated chalk - 600 g.
Mix chalk with water until smooth.
It is allowed to use chalk-based tooth powder instead of chalk.
E.3.4 Developer P4:
auxiliary substance OP-7 (OP-10) - 1 g;
distilled water - 530 ml;
white soot grade BS-30 (BS-50) - 100 g;
Rectified technical ethyl alcohol - 360 ml.
Dissolve the auxiliary substance in water, pour alcohol into the solution and introduce soot. Mix the resulting composition thoroughly.
It is allowed to replace the auxiliary substance with a synthetic detergent of any brand.
E.3.5 Developer P5:
acetone - 570 ml;
nefras - 280 ml;
white soot grade BS-30 (BS-50) - 150 g.
Add soot to the solution of acetone and nefras and mix thoroughly.
E.3.6 White developing paint M.
Paint M is a homogeneous mixture of film former, pigment and solvents.
During storage, as well as during prolonged (more than 7 hours) exposure to negative temperatures (up to -30 ° C and below), the pigment of paint M precipitates, so before use and when pouring into another container, it should be thoroughly mixed.
The guaranteed shelf life of M paint is 12 months from the date of issue. After this period, paint M is subject to sensitivity testing in accordance with Appendix G.
E.4 Compositions for degreasing the controlled surface
E.4.1 Composition C1:
auxiliary substance OP-7 (OP-10) - 60 g;
drinking water - 1000 ml.
E.4.2 Composition of C2:
auxiliary substance OP-7 (OP-10) - 50 g;
drinking water - 1000 ml;
monoethanolamine - 10 g.
E.4.3 Composition of C3:
drinking water 1000 ml;
synthetic detergent (CMC) of any brand - 50 g.
E.4.4 Dissolve the components of each of the compositions C1 - C3 in water at a temperature of 70 - 80 °C.
Compositions C1 - C3 are applicable for degreasing any grades of metals and their alloys.
E.4.5 Composition of C4:
auxiliary substance OP-7 (OP-10) - 0.5 - 1.0 g;
drinking water - 1000 ml;
technical caustic sodium grade A - 50 g;
sodium phosphate trisubstituted - 15 - 25 g;
soluble sodium silicate - 10 g;
soda ash - 15 - 25 g.
E.4.6 Composition of C5:
drinking water - 1000 ml;
sodium phosphate trisubstituted 1 - 3 g;
soluble sodium silicate - 1 - 3 g;
soda ash - 3 - 7 g.
E.4.7 For each of the compositions C4 - C5:
Dissolve soda ash in water at a temperature of 70 - 80 ° C, add other components of a specific composition to the resulting solution one by one, in the specified sequence.
Compositions C4 - C5 should be used when inspecting objects made of aluminum, lead and their alloys.
After applying compositions C4 and C5, the controlled surface should be washed with clean water and neutralized with a 0.5% aqueous solution of sodium nitrite.
Compositions C4 and C5 are not allowed to come into contact with the skin.
E.4.8 It is allowed to replace the auxiliary substance in compositions C1, C2 and C4 with a synthetic detergent of any brand.
E.5 Organic solvents
Gasoline B-70
Nefras S2-80/120, S3-80/120
The use of organic solvents must be carried out in accordance with the requirements of section 9.
G.1 Flaw detection materials should be stored in accordance with the requirements of the standards or technical specifications that apply to them.
G.2 Sets of flaw detection materials should be stored in accordance with the requirements of the documents for the materials from which they are composed.
G.3 Indicator penetrants and developers should be stored in airtight containers. Indicator penetrants must be protected from light.
G.4 Degreasing compositions and developers should be prepared and stored in unbreakable containers based on shift needs.
G.5 The quality of flaw detection materials should be checked on two control samples. One sample (working) should be used continuously. The second sample is used as an arbitration sample if cracks are not detected on the working sample. If cracks are also not detected on the arbitration sample, then the flaw detection materials should be considered unsuitable. If cracks are detected on the arbitration sample, the working sample should be thoroughly cleaned or replaced.
The control sensitivity (K), when using a control sample in accordance with Figure D.1, should be calculated using the formula:
where L 1 is the length of the undetected zone, mm;
L is the length of the indicator trace, mm;
S - probe thickness, mm.
G.6 After use, control samples should be washed in a cleaner or acetone with a bristle brush or brush (the sample according to Figure G.1 must first be disassembled) and dried with warm air or wiped with dry, clean cloth napkins.
G.7 The results of testing the sensitivity of flaw detection materials must be entered in a special journal.
G.8 Aerosol cans and vessels with flaw detection materials must have a label with data on their sensitivity and the date of the next test.
(informative)
Table I.1
Approximate consumption of auxiliary materials and accessories per 10 m 2 of controlled surface
K.1 Method for assessing the quality of degreasing with solvent drops
K.1.1 Apply 2 - 3 drops of nefras to the grease-free area of the surface and leave for at least 15 s.
K.1.2 Place a sheet of filter paper on the area with drops and press it to the surface until the solvent is completely absorbed into the paper.
K.1.3 Apply 2 - 3 drops of nefras to another sheet of filter paper.
K.1.4 Leave both sheets until the solvent evaporates completely.
K.1.5 Compare visually appearance both sheets of filter paper (illumination must correspond to the values given in Appendix B).
K.1.6 The quality of surface degreasing should be assessed by the presence or absence of stains on the first sheet of filter paper.
This method is applicable to assess the quality of degreasing of a controlled surface with any degreasing compositions, including organic solvents.
K.2 Method for assessing the quality of degreasing by wetting.
K.2.1 Moisten the grease-free area of the surface with water and leave for 1 minute.
K.2.2 The quality of degreasing should be assessed visually by the absence or presence of water drops on the controlled surface (lighting should correspond to the values given in Appendix B).
This method should be used when cleaning the surface with water or aqueous degreasing compounds.
|
Date of control |
Information about the object of control |
Sensitivity class, set of flaw detection materials |
Identified defects |
conclusion on the control results |
Flaw detectorist |
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name, drawing number |
grade of material |
No. or designation of the welded joint according to drawing. |
No. of controlled area |
during primary control |
during control after the first correction |
during control after re-correction |
last name, ID number |
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Notes: 1 In the column “Identified defects” the dimensions of the indicator marks should be given. 2 If necessary, sketches of the location of indicator traces should be attached. 3 Designations of identified defects - according to Appendix N. 4 Technical documentation on the results of control should be stored in the archives of the enterprise in the prescribed manner. |
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Company_____________________________ Name of the control object____________________________________________________ Head No. ___________________________________Inv. No. _________________________________ |
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CONCLUSION No. _____ from
___________________ |
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Flaw detector _____________ /____________________/, certificate No. _______________ Head of NDT service ______________ /______________/ |
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H.1 Control record
P - (I8 M3 P7),
where P is the second class of control sensitivity;
I8 - indicator penetrant I8;
M3 - M3 cleaner;
P7 - P7 developer.
The industry designation of a set of flaw detection materials should be indicated in brackets:
P - (DN-7C).
H.2 Identification of defects
N - lack of penetration; P - it's time; Pd - undercut; T - crack; Ш - slag inclusion.
A - single defect without a predominant orientation;
B - group defects without a predominant orientation;
B - ubiquitously distributed defects without a predominant orientation;
P - location of the defect parallel to the axis of the object;
The location of the defect is perpendicular to the object axis.
Designations of acceptable defects indicating their location must be circled.
Note - A through defect should be indicated with a “*” sign.
H.3 Recording inspection results
2TA+-8 - 2 single cracks, located perpendicular to the axis of the weld, 8 mm long, unacceptable;
4PB-3 - 4 pores located in a group without a predominant orientation, with an average size of 3 mm, unacceptable;
20-1 - 1 group of pores 20 mm long, located without a predominant orientation, with an average pore size of 1 mm, acceptable.
The control sample was certified ______ (date) ______ and found suitable for determining the sensitivity of control using the color method according to ___________ class GOST 18442 using a set of flaw detection materials
_________________________________________________________________________
A photo of the control sample is attached.
Signature of the head of the non-destructive testing service of the enterprise
Russia Moldova China Belarus Armada NDT YXLON International Time Group Inc. Testo Sonotron NDT Sonatest SIUI SHERWIN Babb Co Rigaku RayCraft Proceq Panametrics Oxford Instrument Analytical Oy Olympus NDT NEC Mitutoyo Corp. Micronics Metrel Meiji Techno Magnaflux Labino Krautkramer Katronic Technologies Kane JME IRISYS Impulse-NDT ICM HELLING Heine General Electric Fuji Industrial Fluke FLIR Elcometer Dynameters DeFelsko Dali CONDTROL COLENTA CIRCUTOR S.A. Buckleys Balteau-NDT Andrew AGFA
Capillary method for studying defects is a concept that is based on the penetration of certain liquid formulations into the surface layers of the necessary products, carried out using capillary pressure. Using this process, it is possible to significantly increase the lighting effects, which are able to more thoroughly identify all defective areas.
A fairly common occurrence that can occur in flaw detection, this is not a sufficiently complete identification of the necessary defects. Such results are very often so small that a general visual inspection is not able to recreate all defective areas of different products. For example, using this measuring equipment, like a microscope or a simple magnifying glass, it is impossible to determine surface defects. This occurs as a result of insufficient contrast in the existing image. Therefore, in most cases, the highest quality control method is penetrant flaw detection. This method uses indicator liquids that completely penetrate the surface layers of the material under study and form indicator prints, with the help of which further registration occurs visually. You can get acquainted with it on our website.
The most important condition for a high-quality method for detecting various defective violations in finished products type capillary method is the acquisition of special cavities that are completely free from the possibility of contamination, and have additional access to the surface areas of objects, and are also equipped with depth parameters that far exceed the width of their opening. The values of the capillary research method are divided into several categories: basic, which support only capillary phenomena, combined and combined, using a combination of several control methods.
Flaw detection, which uses the capillary inspection method, is designed to examine the most hidden and inaccessible defective areas. Such as cracks, various types of corrosion, pores, fistulas and others. This system is used to correctly determine the location, length and orientation of defects. Its work is based on the thorough penetration of indicator liquids into the surface and heterogeneous cavities of the materials of the controlled object. .
The process of changing the saturation of the pattern and displaying the defect can be changed in two ways. One of them involves polishing upper layers controlled object, which subsequently performs etching using acids. Such processing of the results of the controlled object creates a filling with corrosion substances, which results in darkening and then manifestation on the light-colored material. This process has several specific prohibitions. These include: unprofitable surfaces that may be poorly polished. Also, this method of detecting defects cannot be used if non-metallic products are used.
The second process of change is the light output of defects, which implies their complete filling with special color or indicator substances, so-called penetrants. You definitely need to know that if the penetrant contains luminescent compounds, then this liquid will be called luminescent. And if the main substance is a dye, then all flaw detection will be called color. This control method contains dyes only in rich red shades.
Sequence of operations for capillary control:
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Pre-cleaning |
Mechanically, brush |
Jet method |
Hot steam degreasing |
Solvent cleaning |
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Pre-drying |
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Application of penetrant |
Immersion in the bath |
Application by brush |
Aerosol/spray application |
Electrostatic application |
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Intermediate cleaning |
A lint-free cloth or sponge soaked in water |
Water-soaked brush |
Rinse with water |
A lint-free cloth or sponge soaked in a special solvent |
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Air dry |
Wipe with a lint-free cloth |
Blow with clean, dry air |
Dry with warm air |
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Applying developer |
Immersion (water-based developer) |
Aerosol/spray application (alcohol based developer) |
Electrostatic application (alcohol based developer) |
Applying dry developer (for highly porous surfaces) |
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Surface inspection and documentation |
Control during daytime or artificial lighting min. 500Lux (EN 571-1/EN3059) When using fluorescent penetrant: Lighting:< 20 Lux UV intensity: 1000μW/cm2 |
Documentation on transparent film |
Photo-optical documentation |
Documentation through photography or video |
The main capillary methods of non-destructive testing are divided depending on the type of penetrating substance into the following:
· The method of penetrating solutions is a liquid method of capillary non-destructive testing, based on the use of a liquid indicator solution as a penetrating substance.
· The method of filterable suspensions is a liquid method of capillary non-destructive testing, based on the use of an indicator suspension as a liquid penetrating substance, which forms an indicator pattern from filtered particles of the dispersed phase.
Capillary methods, depending on the method of identifying the indicator pattern, are divided into:
· Luminescent method, based on recording the contrast of a visible indicator pattern luminescent in long-wave ultraviolet radiation against the background of the surface of the test object;
· contrast (color) method, based on recording the contrast of a color indicator pattern in visible radiation against the background of the surface of the test object.
· fluorescent color method, based on recording the contrast of a color or luminescent indicator pattern against the background of the surface of the test object in visible or long-wave ultraviolet radiation;
· luminance method, based on recording the contrast in visible radiation of an achromatic pattern against the background of the surface of the test object.
Always in stock! With us you can (color flaw detection) at a low price from a warehouse in Moscow: penetrant, developer, cleaner Sherwin, capillary systemsHelling, Magnaflux, ultraviolet lights, ultraviolet lamps, ultraviolet illuminators, ultraviolet lamps and control (standards) for color flaw detection of CDs.
We deliver consumables for color flaw detection throughout Russia and the CIS by transport companies and courier services.
COMPLETED: LOPATINA OKSANA
Penetrant flaw detection - a flaw detection method based on the penetration of certain liquid substances into surface defects of a product under the action of capillary pressure, as a result of which the light and color contrast of the defective area relative to the undamaged area increases.
Penetrant flaw detection (penetrant testing) designed to identify invisible or weakly visible to the naked eye surface and through defects (cracks, pores, cavities, lack of fusion, intercrystalline corrosion, fistulas, etc.) in test objects, determining their location, extent and orientation along the surface.
Indicator liquid(penetrant) is a colored liquid designed to fill open surface defects and subsequently form an indicator pattern. The liquid is a solution or suspension of dye in a mixture of organic solvents, kerosene, oils with the addition of surfactants (surfactants) that reduce the surface tension of water located in defect cavities and improve the penetration of penetrants into these cavities. Penetrants contain dyes (color method) or luminescent additives (luminescent method), or a combination of both.
Cleaner– serves for preliminary cleaning of the surface and removal of excess penetrant
Developer is a flaw detection material designed to extract penetrant from a capillary discontinuity in order to form a clear indicator pattern and create a contrasting background. There are five main types of developers used with penetrants:
Dry powder; - aqueous suspension; - suspension in solvent; - solution in water; - plastic film.
Devices and equipment for capillary control:
Materials for color flaw detection, Luminescent materials
Kits for penetrant flaw detection (cleaners, developers, penetrants)
Sprayers, Pneumatic-hydraulic guns
Sources of ultraviolet lighting (ultraviolet lamps, illuminators).
Test panels (test panel)
Control samples for color flaw detection.
The penetrant testing process consists of 5 stages:
1 – preliminary cleaning of the surface. To ensure that the dye can penetrate into defects on the surface, it must first be cleaned with water or an organic cleaner. All contaminants (oils, rust, etc.) and any coatings (paintwork, metallization) must be removed from the controlled area. After this, the surface is dried so that no water or cleaner remains inside the defect.
2 – application of penetrant. The penetrant, usually red in color, is applied to the surface by spraying, brushing or dipping the test object into a bath to ensure good penetration and complete coverage of the penetrant. As a rule, at a temperature of 5...50°C, for a time of 5...30 minutes.
3 - removal of excess penetrant. Excess penetrant is removed by wiping with a cloth, rinsing with water, or with the same cleaner as at the pre-cleaning stage. In this case, the penetrant should be removed only from the control surface, but not from the defect cavity. Then the surface is dried with a lint-free cloth or a stream of air.
4 – application of developer. After drying, a developer (usually white) is immediately applied to the control surface in a thin, even layer.
5 - control. Identification of existing defects begins immediately after the end of the development process. During control, indicator traces are identified and recorded. The intensity of the color indicates the depth and width of the defect; the paler the color, the smaller the defect. Deep cracks have intense coloring. After testing, the developer is removed with water or a cleaner.
To the disadvantages capillary testing should include its high labor intensity in the absence of mechanization, the long duration of the control process (from 0.5 to 1.5 hours), as well as the complexity of mechanization and automation of the control process; decreased reliability of results at subzero temperatures; subjectivity of control - dependence of the reliability of the results on the professionalism of the operator; limited shelf life of flaw detection materials, dependence of their properties on storage conditions.
The advantages of capillary control are: simplicity of control operations, simplicity of equipment, applicability to a wide range of materials, including non-magnetic metals. The main advantage of capillary flaw detection is that with its help it is possible not only to detect surface and through defects, but also to obtain, from their location, extent, shape and orientation along the surface, valuable information about the nature of the defect and even some of the reasons for its occurrence (stress concentration, non-compliance technology, etc.).
Flaw detection materials for color flaw detection are selected depending on the requirements for the controlled object, its condition and control conditions. The transverse size of the defect on the surface of the test object is taken as a defect size parameter - the so-called defect opening width. The minimum value of disclosure of detected defects is called the lower sensitivity threshold and is limited by the fact that a very small amount of penetrant retained in the cavity of a small defect is insufficient to obtain a contrast indication for a given thickness of the developing substance layer. There is also an upper sensitivity threshold, which is determined by the fact that the penetrant is washed out of wide but shallow defects when excess penetrant is removed from the surface. The detection of indicator traces corresponding to the main characteristics indicated above serves as the basis for an analysis of the admissibility of the defect in terms of its size, nature, and position. GOST 18442-80 establishes 5 sensitivity classes (lower threshold) depending on the size of defects
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Sensitivity class |
Defect opening width, µm |
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From 10 to 100 |
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From 100 to 500 |
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technological |
Not standardized |
Class 1 sensitivity controls the blades of turbojet engines, sealing surfaces of valves and their seats, metal sealing gaskets of flanges, etc. (detectable cracks and pores up to tenths of a micron in size). Class 2 tests reactor housings and anti-corrosion surfacing, base metal and welded connections of pipelines, bearing parts (detectable cracks and pores up to several microns in size). Class 3 tests the fasteners of a number of objects, with the ability to detect defects with an opening of up to 100 microns; class 4 – thick-walled castings.
Capillary methods, depending on the method of identifying the indicator pattern, are divided into:
· Luminescent method, based on recording the contrast of a visible indicator pattern luminescent in long-wave ultraviolet radiation against the background of the surface of the test object;
· contrast (color) method, based on recording the contrast of a color indicator pattern in visible radiation against the background of the surface of the test object.
· fluorescent color method, based on recording the contrast of a color or luminescent indicator pattern against the background of the surface of the test object in visible or long-wave ultraviolet radiation;
· luminance method, based on registering the contrast in visible radiation of an achromatic pattern against the background of the object’s surface.
PERFORMED BY: VALYUKH ALEXANDER
Penetrant control
Penetrant non-destructive testing method
CapillIflaw detectorAndI - a flaw detection method based on the penetration of certain liquid substances into surface defects of a product under the action of capillary pressure, as a result of which the light and color contrast of the defective area relative to the undamaged area increases.
In most cases, according to technical requirements, it is necessary to identify defects so small that they can be noticed when visual inspection almost impossible with the naked eye. The use of optical measuring instruments, such as a magnifying glass or a microscope, does not allow identifying surface defects due to insufficient contrast of the image of the defect against the background of the metal and a small field of view at high magnifications. In such cases, the capillary control method is used.
During capillary testing, indicator liquids penetrate into the cavities of surface and through discontinuities in the material of the test objects, and the resulting indicator traces are recorded visually or using a transducer.
Testing by the capillary method is carried out in accordance with GOST 18442-80 “Non-destructive testing. Capillary methods. General requirements."
Capillary methods are divided into basic, using capillary phenomena, and combined, based on a combination of two or more non-destructive testing methods of different physical nature, one of which is penetrant testing (penetrant flaw detection).
Penetrant flaw detection (penetrant testing) designed to identify invisible or weakly visible to the naked eye surface and through defects (cracks, pores, cavities, lack of fusion, intercrystalline corrosion, fistulas, etc.) in test objects, determining their location, extent and orientation along the surface.
Capillary methods of non-destructive testing are based on capillary penetration of indicator liquids (penetrants) into the cavities of surface and through discontinuities of the material of the test object and registration of the resulting indicator traces visually or using a transducer.
The capillary testing method is used to control objects of any size and shape made of ferrous and non-ferrous metals, alloy steels, cast iron, metal coatings, plastics, glass and ceramics in the energy sector, aviation, rocketry, shipbuilding, the chemical industry, metallurgy, and in the construction of nuclear power plants. reactors, in the automotive industry, electrical engineering, mechanical engineering, foundry, stamping, instrument making, medicine and other industries. For some materials and products, this method is the only one for determining the suitability of parts or installations for work.
Penetrant flaw detection is also used for non-destructive testing of objects made of ferromagnetic materials, if their magnetic properties, shape, type and location of defects do not allow achieving the sensitivity required by GOST 21105-87 using the magnetic particle method and the magnetic particle testing method is not allowed to be used due to the operating conditions of the object.
A necessary condition for identifying defects such as a violation of the continuity of a material by capillary methods is the presence of cavities that are free from contaminants and other substances that have access to the surface of objects and a depth of distribution that significantly exceeds the width of their opening.
Penetrant testing is also used for leak detection and, in combination with other methods, for monitoring critical facilities and facilities during operation.
The advantages of capillary flaw detection methods are: simplicity of control operations, simplicity of equipment, applicability to a wide range of materials, including non-magnetic metals.
The advantage of penetrant flaw detection is that with its help it is possible not only to detect surface and through defects, but also to obtain, from their location, extent, shape and orientation along the surface, valuable information about the nature of the defect and even some of the reasons for its occurrence (stress concentration, non-compliance with technology, etc.). ).
Organic phosphors are used as indicator liquids - substances that produce a bright glow of their own when exposed to ultraviolet rays, as well as various dyes. Surface defects are detected using means that make it possible to extract indicator substances from the defect cavity and detect their presence on the surface of the controlled product.
Capillary (crack), facing the surface of the test object only on one side is called a surface discontinuity, and connecting the opposite walls of the test object is called through. If surface and through discontinuities are defects, then it is permissible to use the terms “surface defect” and “through defect” instead. The image formed by the penetrant at the location of the discontinuity and similar to the cross-sectional shape at the exit to the surface of the test object is called an indicator pattern, or indication.
In relation to a discontinuity such as a single crack, instead of the term “indication”, the term “indicator mark” can be used. Discontinuity depth is the size of the discontinuity in the direction inward of the test object from its surface. Discontinuity length is the longitudinal size of a discontinuity on the surface of an object. Discontinuity opening is the transverse size of the discontinuity at its exit to the surface of the test object.
A necessary condition for the reliable detection of defects that reach the surface of an object by the capillary method is their relative freedom from contamination by foreign substances, as well as a depth of distribution that significantly exceeds the width of their opening (minimum 10/1). A cleaner is used to clean the surface before applying penetrant.
Capillary flaw detection methods are divided into into basic ones, using capillary phenomena, and combined ones, based on a combination of two or more non-destructive testing methods that are different in physical essence, one of which is capillary testing.
Non-destructive testing becomes important when the development of a coating has already been completed and it is possible to move on to its industrial application. Before a coated product goes into service, it is checked for strength and the absence of cracks, discontinuities, pores or other defects that could cause destruction. The more complex the object being coated, the greater the likelihood of defects. Table 1 presents and describes below existing non-destructive methods for determining the quality of coatings.
Table 1. Non-destructive methods quality control of coatings before their use.
| # | Control method | Purpose and suitability of the test |
| 1 | Visual observation | Detection of surface coating defects by visual inspection |
| 2 | Penetrant inspection (color and fluorescent) | Detection of surface cracks, pores and similar coating defects |
| 3 | Radiographic control | Detection of internal coating defects |
| 4 | Electromagnetic control | Detection of pores and cracks, the method is not suitable for identifying defects in corners and edges |
| 5 | Ultrasonic testing | Detection of surface and internal defects, the method is not suitable for thin layers and for detecting defects in corners and edges |
The simplest quality assessment is an external inspection of a coated product. Such control is relatively simple, it becomes especially effective in good lighting, when using a magnifying glass. In general, external inspection should be performed by qualified personnel and in combination with other methods.
Cracks and depressions on the surface of the coating are revealed by the absorption of paint. The surface to be tested is sprayed with paint. It is then thoroughly wiped and an indicator is sprayed onto it. After a minute, paint emerges from cracks and other small defects and colors the indicator, thus revealing the outline of the crack.
This method is similar to the paint absorption method. The test sample is immersed in a solution containing fluorescent dye, which gets into all the cracks. After cleaning the surface, the sample is coated with a new solution. If the coating has any defects, the fluorescent paint in this area will be visible under ultraviolet irradiation.
Both absorption-based techniques are used only to detect surface defects. Internal defects are not detected. Defects lying on the surface itself are difficult to detect, since wiping the surface before applying the indicator removes the paint from them.
Penetrating radiation inspection is used to identify pores, cracks and cavities within the coating. X-rays and gamma rays pass through the material being tested and onto the photographic film. The intensity of x-rays and gamma radiation changes as they pass through the material. Any pores, cracks or changes in thickness will be recorded on the photographic film, and by appropriate decoding of the film, the position of any internal defects can be determined.
Radiographic testing is relatively expensive and slow. The operator must be protected from radiation. It is difficult to analyze products with complex shapes. Defects are determined when their size is more than 2% of the total coating thickness. Consequently, radiographic technology is unsuitable for identifying small defects in large structures of complex shape; it gives good results on less complex products.
Surface and internal defects can be determined using eddy currents induced in the product by introducing it into the electromagnetic field of the inductor. When a part moves in an inductor, or an inductor relative to a part, the induced eddy currents interact with the inductor and change its impedance. The induced current in a sample depends on the presence of conduction defects in the sample, as well as its hardness and size.
By using appropriate inductances and frequencies, or a combination of both, defects can be identified. Eddy current monitoring is not practical if the product configuration is complex. This type of inspection is not suitable for detecting defects on edges and corners; in some cases from uneven surface the same signals as from the defect may be received.
In ultrasonic testing, ultrasound is passed through a material and changes in the sound field caused by defects in the material are measured. The energy reflected from defects in the sample is sensed by a transducer, which turns it into an electrical signal and is fed to an oscilloscope.
Depending on the size and shape of the sample, longitudinal, transverse or surface waves are used for ultrasonic testing. Longitudinal waves propagate in a straight line through the test material until they encounter a boundary or discontinuity. The first boundary that the incoming wave encounters is the boundary between the transducer and the product. Part of the energy is reflected from the boundary, and a primary pulse appears on the oscilloscope screen. The remaining energy travels through the material until it encounters a defect or the opposing surface, the position of the defect being determined by measuring the distance between the signal from the defect and from the front and rear surfaces.
Discontinuities can be positioned so that they can be identified by directing radiation perpendicular to the surface. In this case, the sound beam is introduced at an angle to the surface of the material to create transverse waves. If the entry angle is increased sufficiently, surface waves are formed. These waves follow the contour of the sample and can detect defects near its surface.
There are two main types of ultrasonic testing units. Resonance testing uses radiation with a variable frequency. When the natural frequency corresponding to the thickness of the material is reached, the amplitude of the oscillations increases sharply, which is reflected on the oscilloscope screen. The resonance method is mainly used to measure thickness.
With the pulse echo method, pulses of constant frequency lasting a fraction of a second are introduced into the material. The wave passes through the material and the energy reflected from the defect or back surface is incident on the transducer. The transducer then sends out another pulse and receives the reflected one.
To identify defects in the coating and to determine the adhesion strength between the coating and the substrate, the transmission method is also used. In some coating systems, reflected energy measurement does not adequately identify the defect. This is due to the fact that the boundary between the coating and the substrate is characterized by such a high reflection coefficient that the presence of defects changes the total reflection coefficient little.
The use of ultrasonic testing is limited. This can be seen from the following examples. If the material has a rough surface, the sound waves are scattered so much that the test becomes meaningless. To test objects of complex shape, transducers are needed that follow the contour of the object; Surface irregularities cause blips to appear on the oscilloscope screen, making it difficult to identify defects. Grain boundaries in metal act similarly to defects and scatter sound waves. Defects located at an angle to the beam are difficult to detect, since reflection occurs mainly not in the direction of the converter, but at an angle to it. It is often difficult to distinguish discontinuities located close to one another. In addition, only those defects whose dimensions are comparable to the sound wavelength are detected.
Selection tests are undertaken during initial stage coating development. Because during the search period optimal mode the number of different samples is very large, a combination of test methods is used to weed out unsatisfactory samples. This selection program usually consists of several types of oxidation tests, metallographic examination, flame testing and tensile testing. Coatings that successfully pass selection tests are tested under conditions similar to operational ones.
Once a particular coating system has been determined to pass field testing, it can be applied to protect the actual product. It is necessary to develop a technique for non-destructive testing of the final product before putting it into operation. Non-destructive techniques can be used to identify surface and internal holes, cracks and discontinuities, as well as poor adhesion between the coating and the substrate.
