Cast iron cutting methods can be divided into mechanical and thermal, there are also special tool for certain tasks. Next, we will consider methods and various cases.
The simplest and available method. Cons: cutting only occurs in a straight line. Say, cutting a pipe is possible, but cutting out some part will be very difficult, however, in everyday life this method is used mainly for installing plumbing and heating equipment. It is worth noting that this is a fire hazardous method. Required additional protection for face and eyes.
When cutting cast iron with a grinder, you should pay attention Special attention on cutting wheels. Bakelite-bonded cutting discs are now very popular; they are more durable and resilient than ceramic-bonded consumables.
For cutting cast iron pipes, there are specialized pipe cutters. For example, Exact Pipecut - portable electric pipe cutters, for working with pipes with a diameter of Ø 15 - 360
Pipes made of steel, copper, cast iron, of stainless steel and plastics can be cut using EXACT Pipecut 170, 200 and 360 pipe cutters. The use of TCT carbide discs on pipe cutters gives a huge advantage over traditional abrasive wheels cutting speed is four times higher, no sparks during cutting, cutting without adding coolant to the cutting zone. Diamond-coated carbide discs are used for cutting cast iron pipes.
Purpose: manual cutting of high-carbon and high-alloy steels, cast iron, non-ferrous metals and their alloys, concrete and reinforced concrete, composite and other materials. The cutting principle is based on the destructive effect on the material of a high-temperature supersonic jet of combustion products of liquid hydrocarbon fuel (kerosene, diesel fuel) in oxygen. Areas of application: recycling of objects and metal structures, emergency rescue operations, liquidation of consequences emergency situations, metallurgical production, construction, transport, etc.
Oxygen lance cutting. An oxygen lance is a steel tube through which oxygen is passed. The working end of the oxygen lance is heated to 1350°C (for example, with a welding torch), then oxygen is pressurized, which ignites at the end of the lance and reaches a temperature of 2000°C. To increase the power of the spear, a steel rod is placed inside the tube.
Cutting cast iron is the most productive option, but it is also the most expensive.
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Oxygen cutting of cast iron without flux is also difficult, since the melting point of cast iron is lower than the combustion temperature of iron. The silicon contained in cast iron produces a refractory oxide film that prevents normal cutting. When the carbon in cast iron burns, it produces carbon monoxide gas, which contaminates the cutting oxygen and prevents the combustion of the iron.
It is possible to cut cast iron without flux, only by using a more powerful oxy-acetylene flame with an excess of acetylene. The flame core should have a length equal to the thickness of the cast iron being cut. Cutting is performed with transverse oscillatory movements of the mouthpiece, creating a wider cut. This method consumes more metal, oxygen and acetylene than when cutting steel, and the cut is uneven, with melted edges. Therefore, for high-quality cutting of cast iron, oxygen-flux cutting is also used.
Non-ferrous metals (copper, brass, bronze) have high thermal conductivity and when they are oxidized with oxygen, an amount of heat is released that is insufficient for the further development of the metal combustion process. When oxy-fuel cutting of these metals, refractory oxides are also formed, which interfere with cutting. Therefore, oxygen cutting of bronze and brass is only possible with the use of fluxes.
When cutting cast iron, ferrophosphorus or aluminum powder and quartz sand are added to the powder. The speed of oxygen-flux cutting of cast iron is 50-55% lower than the speed of cutting stainless steel. When cutting copper and bronze, ferrophosphorus, aluminum and quartz sand are added to the flux, and cutting is carried out with heating to 200-400 °C.
Gas arc cutting
Behind last years Gas-arc cutting methods have become widespread: air-arc, plasma-arc and plasma. They are used for cutting many metals and alloys. In some cases, oxygen-arc cutting of steel is also used. Gas arc cutting methods are now used in many enterprises, which provides great savings in national economy. Work is underway on mechanization and automation of gas-arc cutting.
Air arc cutting
This cutting method is based on melting the metal at the cutting site with a sliding electric arc, burning between a carbon electrode and metal, with continuous removal of liquid metal by a jet compressed air. Used as parting and surface cutting. Can also be used for air arc cutting alternating current, however, it gives less performance than constant.
Air-arc cutting is widely used for surface cutting of most ferrous and non-ferrous metals, cutting out defective areas of welds, cutting rivets, punching holes, cutting off the profits of steel castings, etc. This method can cut various metals (stainless steels, cast iron, brass and hard-to-oxidize alloys ) up to 20-25 mm thick.
Plasma arc cutting
In plasma arc cutting, an arc is excited between the metal being cut and a non-consumable tungsten electrode (with the addition of lanthanum) located inside an electrically insulated forming tip. In most cases, a direct current arc of straight polarity is used. The gas blown through the nozzle compresses the arc, provides intense plasma formation in it and gives the arc penetrating properties. In this case, the gas is heated to high temperatures (10,000 – 20,000 °C), which ensures a high flow rate and a strong mechanical effect of the plasma on the molten metal blown out from the cut site.
It is advisable to use plasma-arc cutting: in the manufacture of parts with shaped contours from sheets; production of parts with straight contours that do not require machining; cutting openings and holes in metals; cutting strips, rods, pipes and profiles and giving their ends the desired shape; processing the edges of forgings and preparing them for welding; cutting blanks for machining, stamping and welding; casting processing.
Compared to oxygen plasma-arc cutting, it has the following advantages: the ability to cut any materials on the same equipment; high cutting speed of metals of small thickness (up to 20 mm); the use of inexpensive and non-scarce gases and the absence of consumption of flammable gases (hydrocarbons); small thermal deformations of cut parts; relative simplicity of automation of the cutting process, determined mainly by electrical parameters.
The disadvantages of plasma arc cutting are: more complex and expensive equipment, including a power source and arc control; more complex maintenance; the need to use water cooling of the torch and protective masks with light filters for the cutter; the need for higher qualifications of the cutter.
It is advisable to use plasma-arc cutting when processing metals that are difficult or impossible to cut with others, or when plasma-arc cutting is the most economical, or provides cutting speeds consistent with those accepted in the processing technology of a particular product. Plasma arc cutting processes aluminum and its alloys; copper and its alloys; stainless high-alloy steels; low carbon steel; cast iron; magnesium and its alloys; titanium. The ability to cut metal of a given thickness and the intensity of penetration are determined by the arc power, i.e., the magnitude of current and voltage.
The cutting speed is controlled by changing the arc current (controlling the power supply). The cutting speed decreases rapidly with increasing metal thickness and at the same time the cutting width increases. When cutting manually, a uniform process is ensured at speeds of up to 2 m/min.
Hydrogen and nitrogen dissociate (split into atoms) in the arc, and then their atoms recombine into molecules (recombine) on the colder parts of the metal, releasing a large number of additional heat. This contributes to a more favorable distribution of heat throughout the entire volume of the metal, which is of particular importance when cutting thick metal.
When cutting, the following plasma-forming gases and mixtures are usually used.
For cutting aluminum alloys It is more expedient to use nitrogen-hydrogen mixtures. It is recommended to cut alloys with a thickness of 5-20 mm in nitrogen, and those with a thickness of 20-100 mm in a nitrogen-hydrogen mixture. Argon-hydrogen mixtures when cutting aluminum alloys are used when it is necessary to obtain particularly clean cuts. When cutting manually, the hydrogen content in the argon-hydrogen mixture is reduced to 20%, since with a lower hydrogen content it is easier to maintain the arc when the distance between the nozzle and the metal fluctuates.
When cutting stainless steels up to 50 mm thick, a mixture of oxygen and nitrogen is used, which, flowing along the electrode, protects it from oxidation, as well as nitrogen and a nitrogen-hydrogen mixture. When high-speed burr-free cutting of stainless steels, a mixture of oxygen with 20-25% nitrogen should be used.
Stainless steels of small thickness (up to 20 mm), the edges of which do not require high resistance to intergranular corrosion, can be cut in nitrogen, and stainless steels with a thickness of 20 - 50 mm can be cut in a nitrogen-hydrogen mixture. With increased requirements regarding edge resistance to intergranular corrosion, stainless steels are cut in a nitrogen-hydrogen mixture. The resulting edges can be butt welded without filler wire.
Mixtures with argon are used less frequently when cutting stainless steels. When cutting brass in nitrogen, the cutting speed is 25-30% higher than when cutting copper in nitrogen. For cutting low-carbon steels, it is most advisable to use oxygen or its mixture with a nitrogen content of 25-60%, which, flowing along the tungsten electrode, protects it from oxidation. If necessary, low-carbon steels are falsely cut in nitrogen alone.
Gas consumption during cutting depends only on the type of gas and the metal being cut. In the range of up to 1100 mm of metal thickness, gas consumption remains constant in most cases. In some cases of cutting thin metal, increased gas flow rates are used, which helps eliminate sagging on the lower edges of the cut. For nozzles with a diameter of 3-6 mm, the gas flow rate, as a rule, should not be less than 1.5-2 m3/h in order to avoid the occurrence of a “double” arc, i.e. a second arc between the electrode and the mouthpiece.
Most often, the need to cut a cast iron structure arises when dismantling outdated communications. The hope for a speedy completion of the work collapses immediately - in the Soviet Union, pipes were connected with cement, sulfur and aluminum, so cutting them is incredibly difficult. But a couple of working methods are known. You will learn about how to cut cast iron and structures made from it from the material below.
As with any metal, methods for cutting cast iron are divided into thermal and mechanical. The choice of a specific tool depends on the design features. The following is equipment that saws (or cuts) cast iron:
Now it’s worth evaluating cutting using the mentioned tools with objects made of cast iron.
This is a special device for cutting pipes from different materials. There are manual (mechanical) and electric tools. Both types are suitable for diameters 15-360 mm.
First, a carbide disk is mounted on the device. The removable element has a number of advantages over classic abrasive ones. For example, the cutting speed is increased by 4 times, there is no sparking and no need to add any substances to the cutting zone. Diamond coating is applied on top of the cutting edge, which extends the service life of the products. Examples of pipe cutters for cast iron pipes are portable Exact Pipecut products for diameters less than 360 mm.
Alas, it is rare that a home pipeline can be easily cut with a pipe cutter. It may be difficult for a tool to access it, or the cutting area may be bent so that it cannot be grasped by the device. Therefore, it is worth considering other options.
Working with an angle grinder is quick and convenient, but not without its drawbacks. For example, it only cuts in a straight line. Trying to do figured cut will lead to “biting” of the disk, its breakdown, and possible injury to the user. Therefore, the machine is used for straight cutting. Another disadvantage is the fire hazard of the method (abrasive disc + metal = sparking). Before work, you will have to wear goggles, protection for your face and hands.
Cutting with a circle is more efficient than with a jigsaw, which is why users often choose a noisy grinder. When buying a cutting wheel, prefer products with a bakelite bond, because they are much stronger than their ceramic counterparts.
The operating principle of the device is similar to an angle grinder. You will have to tinker with it for more than one hour, especially if large diameter. The disadvantages of the method are time costs, physical effort, and the inability to work in a limited area. But the method is safe.
This pair of products will help separate cast iron into hard to reach place. Dismantling work begins with pipes remote from the riser in places where a grinder or hacksaw cannot be inserted. Since cast iron is a brittle material, it is easily destroyed after point dynamic loads.
Good percussion instrument has a rubber or polymer attachment to slightly soften the blow. This is necessary so that pieces of cast iron do not fly around, get into the riser and create a blockage.
The chisel and hammer work great with Soviet-era cast iron, that is, combined with sulfur, aluminum and cement. As you move towards the riser free space for work, as a rule, it becomes larger, so further cast iron can be cut off more effective device. As with the grinder, when working with a chisel, it is recommended to cover areas of the body into which cast iron splinters may fly off.
The productivity of work is extremely low, but sometimes you can’t do without them.
It is much more convenient for the user to work with an electric hacksaw than with a grinder, although the principle of operation is not much different. A lightweight device with smaller dimensions than an angle grinder, the blade is consumed slower than the disk if it is correctly selected (HSS or BIM marking, and the length is also taken into account).
Less risk of injury, speed of the process - something between a grinder and a hand saw, low cost of consumables and their availability - are the advantages of cutting cast iron with an electric hacksaw.
The method relates more to production than to household use, so it will not be discussed in detail. If the goal is minimal material consumption, speed of operation, noiselessness, the best equipment no for cutting cast iron. The plasma will make cuts in workpieces with a thickness of more than 200 mm, and the sawn material will hardly have to be processed at the end of the work.
The method is used by large metallurgy and industrial enterprises where there is a need for cutting and transporting cast iron scrap. Plasma installations are indispensable for large-scale work.
There are two methods of gas cutting of cast iron:
In the first case, the workpiece is exposed to a thin jet of flame supplied under high pressure. The combustion product is usually a mixture of oxygen with kerosene or diesel fuel. By the way, effective method when eliminating man-made accidents.
The second method resembles the oxygen gas method, only cutting element a thin tube of hardened steel protrudes. Its tip is heated to almost 1500 degrees (welding/soldering iron/lamp), then oxygen is supplied through it, ignited at the outlet and heated to 2000 degrees. The resulting burning mixture easily copes with thick cast iron.
Both methods are good, but there are disadvantages - it is important to have experience working with gas equipment. Responsible and precise cutting is performed only by a professional. The second drawback is the release of gas that is harmful to health during operation of the cutter.
The method is suitable for working on fresh air or in the garage. For example, the need to eliminate a cast iron lock with swing gates. The cutter works quietly, you won't disturb anyone.
Based on opinion experienced builders and repairmen, in the best ways cutting cast iron perform:
Experienced people advise taking several tools into service when working at home, starting with a chisel and ending with a jigsaw.
Do you know how to quickly saw off a cast iron lock or pipe? Share your experience with readers in the comments.
Methods for cutting cast iron can be divided into mechanical and thermal; there are also special tools for certain tasks. Next, we will consider methods and various cases.
The simplest and most accessible method. Cons: cutting only occurs in a straight line. Let's say you can cut a pipe, but cutting out some part will be very difficult, however, in everyday life this method is used mainly for installing plumbing and heating equipment. It is worth noting that this is a fire hazardous method. Additional protection for face and eyes is required.
When cutting cast iron with a grinder, you should pay special attention to the cutting wheels. Bakelite-bonded cutting discs are now very popular; they are more durable and resilient than ceramic-bonded consumables.
For cutting cast iron pipes, there are specialized pipe cutters. For example Exact Pipecut & portable electric pipe cutters, for working with pipes with a diameter of Ø 15 & 360
Pipes made of steel, copper, cast iron, stainless steel and plastic can be cut using EXACT Pipecut 170, 200 and 360 pipe cutters. The use of TCT carbide discs on pipe cutters gives a huge advantage over traditional abrasive wheels, cutting speed is four times higher, no sparks when cutting, cutting without adding coolant to the cutting zone. Diamond-coated carbide discs are used for cutting cast iron pipes.
Oxygen gas cutting. effective, but limited by the thickness of the metal. If you need to improve the quality of the cut, then you should look towards cutting cast iron using the oxygen-flux method.
For reference: cast iron is an iron alloy that contains at least 2.15% carbon.
An example of cutting cast iron with a supersonic cutter Terminator 220:
It is even suitable for working underwater.
Purpose: manual cutting of high-carbon and high-alloy steels, cast iron, non-ferrous metals and their alloys, concrete and reinforced concrete, composite and other materials. The cutting principle is based on the destructive effect on the material of a high-temperature supersonic jet of combustion products of liquid hydrocarbon fuel in oxygen. Areas of application: recycling of objects and metal structures, rescue operations, liquidation of consequences of emergency situations, metallurgical production, construction, transport, etc.
Oxygen lance cutting. An oxygen lance is a steel tube through which oxygen is passed. The working end of the oxygen lance is heated to 1350°C, then oxygen is pressurized, which ignites at the end of the lance and reaches a temperature of 2000°C. To increase the power of the spear, a steel rod is placed inside the tube.
Cast iron cutting plasma& the most productive option, but it is also the most expensive.
Oxy-acetylene cutting is used mainly for cutting steel castings. This metal cutting is a highly productive and at the same time simple and cheap technological process, therefore it is widely used in almost all foundries, instead of mechanical cutting. The oxygen cutting process lends itself well to mechanization, which has made it possible to create a large number special machines and devices that provide high performance. When gas cutting, unlike mechanical cutting, there is almost no breakage or wear of the tool.
The gas cutting process is based on intense oxidation of metal in a stream of oxygen at high temperature. For the normal process of cutting metal with oxygen, the following conditions must be met:
a) the ignition temperature of the metal must be lower than its melting point;
b) metal oxides formed during cutting must melt at a temperature lower than the temperature of its ignition and melting.
If the metal does not satisfy the first condition, then it will melt and turn into a liquid state even before its combustion in oxygen begins. If the metal does not satisfy the second requirement, then oxygen cutting it without the use of special fluxes is not possible, since the resulting oxides will not be in a liquid state at the combustion temperature of the metal and cannot be removed from the cut site.
The ability of steels to be cut with oxygen depends on their carbon content and alloying impurities. With a carbon content of up to 0.3% in steels, they can still be cut quite well. With a carbon content above 0.3%, steel is prone to hardening and cracking during cutting, so preliminary general heating of the material being cut is required.
The cutting speed depends on several parameters:
On the thickness of the material, its properties, composition and temperature;
On temperature and flame power;
On the shape of the cutting jet and the speed of its flow from the nozzle;
From the pressure of compressed oxygen and its purity.
Impurities in cutting oxygen reduce the cutting speed, from approximately 225 mm/min at 99% oxygen purity to 65 mm/min at 81% oxygen purity. Preheating the casting increases the cutting speed. When steel is heated to 200-370 °C, the cutting speed increases by 50-100%.
At optimal modes cutting, fluctuations in oxygen pressure within ±0.1 MPa change the cutting speed by 25–50%. Excessive increase and decrease in oxygen pressure affects the cutting quality. The cutting speed is also affected by the grade of steel and type of fuel. The speed of manual cutting of carbon steels largely depends on the type of fuel: acetylene, pyrolysis gas, gasoline or kerosene.
Oxy-acetylene cutting time in minutes per linear meter determined by the formula
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Cast iron is cut using direct current of straight polarity.
For cutting cast iron. copper, brass, chromium and chromium-nickel steels, URHS-3 installations are used for oxygen-flux cutting.
For cutting cast iron. non-ferrous metals for which the use of oxygen cutting is impractical, a special oxygen-flux cutting process has been developed and the necessary equipment has been created. The essence of this process is that, together with cutting oxygen, powdered flux is blown into the cutting zone, introduced in suspension by a jet of cutting oxygen. The flux supplied to the cutting zone consists mainly of metallic iron powder. Burning in a stream of oxygen, iron powder produces an additional amount of heat that melts refractory oxides. Iron oxides formed during the combustion of iron powder, fused with the oxides of the metal being cut, form a more fusible and fluid slag, which is more easily blown off the surface of the metal and opens access to oxygen. To obtain flux, powdered fluxing additives are added to the iron powder to facilitate the melting and flow of refractory oxides from the cut cavity. Fluxes are also used, mainly consisting of silicon dioxide Si02, for example quartz sand. The amount of fluxing additives depends on the composition of the metal being cut.
When cutting cast iron, about 35% of blast furnace ferrophosphorus is added to the flux. For cutting copper and its alloys, in addition to 15% ferrophosphorus, up to 25% aluminum is added to the flux. Chromium steels are easily cut using iron powder without any additives.
When cutting cast iron, approximately 35% ferrophosphorus is added to the flux composition. For cutting copper and its alloys, in addition to 15% ferrophosphorus, up to 25% aluminum is added to the flux. Chromium steels are easily cut using iron powder without additives.
As mentioned earlier, this type of cutting involves the combustion of metal in a stream of oxygen. Before this, it is necessary to preheat the cutting area to the ignition temperature. Preheating produces an acetylene flame or a flame of substitute gases. After the cutting site is heated to a temperature of 300-1300°C, cutting oxygen is started. Oxygen cuts the heated metal and at the same time removes the resulting oxides. In order for the process to be continuous, the heating flame must always be in front of the oxygen stream.
Different metals are available to varying degrees for oxy-fuel cutting. Low-carbon steels with a carbon content of no more than 0.3% are cut best. Medium carbon steels cut worse. Cutting high-carbon steels is generally problematic, and if the composition contains more than 1% carbon, cutting is generally impossible without the addition of special fluxes.
High-alloy steels cannot be cut with oxygen. Only oxygen-flux cutting or plasma-arc cutting is possible, which will be discussed in the following chapters. Plasma arc cutting is also used for cutting aluminum and its joints, for which oxygen cutting is excluded. Copper, brass and bronze can only be cut with an oxygen-flux composition, the combustion of which additionally releases heat, increasing the temperature in the cutting zone, as a result of which the resulting oxides do not harden. At the same time, flux combustion products reduce the concentration of refractory oxides and thereby lower their melting point and impart greater fluidity.
Oxy-flux cutting technology basically the same as for conventional oxyfuel cutting. Cutting can be either manual or mechanized. For mechanized cutting, oxygen-flux cutters are installed on any serial gas cutting machine. Both separation and surface oxygen-flux cutting are used. Acetylene and acetylene substitute gases are used as fuel. The compositions of the most common fluxes and iron powders for oxygen-flux cutting are given in Table 1, respectively. 74, 75.
74. Composition and applications of fluxes for oxygen-flux cutting
Sources: b2bresurs.com, studopedia.ru, www.ngpedia.ru, msd.com.ua, electrowelder.ru, fassen.net, delta-grup.ru
Pipe cutting.
To a greater extent, this article is devoted to cutting metal pipes and only at the very end the problems are considered: cutting a plastic pipe, cutting a metal-plastic pipe and cutting a polypropylene pipe.
Pipe, like any other rolled metal product, is produced by the manufacturer at a certain length.
This length is given technological features industrial equipment and in a similar landscape, the pipe goes into production, and then into trade.
When working with pipes, rods and other types of rolled metal, one of the main operations is cutting the pipe.
For what cut pipe?
In order to purchase a piece of pipe after cutting the pipe required size, and then use it for its intended purpose.
This operation is called cutting pipes to size.
When cutting pipes to size, you specify a specific size, usually the length of the pipe.
To cut pipes to size, you use a tape measure to measure the required length of pipe from the straight edge of the pipe and make the necessary markings.
Then, when cutting pipes to size, you direct the cutting tool.
The pipe cutting tool can be obedient or electric and can accommodate a variety of cutting surfaces.
When cutting a pipe, you need to not only get a piece of pipe the right size, but also not to damage the pipe.
There may be a task to cut a pipe at a right angle or to cut a pipe at opposite angles extending from 90 degrees.
There is a demand: how to cut pipe.
The response to this demand has long been familiar and has several options.
From time to time you come across broken beds from lathes.
Buying everything is fabulous, transporting it home is even more so.
Like a machine, this cannot be restored, but I need to cut off a piece of guides from them about 800 mm long and 300 - 500 mm wide to build a sharpening machine (cut the bed perpendicularly).
Autogenem refuses to do this, because cast iron does not play without a special cutter and special powder, which, of course, does not exist and no one has noticed in life.
It’s also fabulous to do this with a grinder.
Obedient saws disappear. Perhaps something can simply be poured onto the leading ones, so that when working with an autogenous saw, it will react with the oxide, lowering the melting point?
Will the pressure of the flames burn him off?
The option, in my opinion, is more realistic - to make deep cuts with a grinder, and then place it under the bed hydraulic jacks and they try to lift the frame like this, since from below the cut is possible - combining with blows of a sledgehammer on the unnecessary part - maybe a crack will appear?
It's really?
can debris fly?
How to cut deep?
A 10 - 20 mm cut is enough - would it be more suitable?
Your option?
its use can be cost-effective if the temperature in the cutting zone remains below 700° C.
To do this, select a tool with zero inclination cutting edges and back angle 7°, itself cutting the edge must be thin; any chamfer increases resistance, and therefore heat generation.
A coolant supply through the tool is required, as well as a plentiful external coolant supply.
Recommended cutting conditions for gray cast iron: cutting speed 150 m/min, feed 0.12 mm/rev and cutting depth 0.25 mm.
This achieves amazing durability.
Cutting pipes by welding.
What to cut pipe.
Tool for cutting pipes by welding - electric welding machine.
The pipe is cut using an electrode.
When cutting pipes with a sark, the pipe plays due to its penetration at high temperatures and increased force applied to the electrode.
The voltage supplied to the electrode is set higher, how when welding pipes.
Pipe cutting by welding is forced measure and is not often used for cutting pipes to size.
Cutting pipes by welding gives approximately the same negative results, What and gas pipe cutting.
He asks for the presence of a welding machine at hand, power in the electrical network and a certain experience of the performer of the work.
Gray and high-strength are the most commonly used materials for the manufacture of automotive components. cast iron.
For processing high-strength cast iron, usually, they spend three times the amount of tools, how for gray processing cast iron.
This state of affairs is explained by the fact that that ductile iron holds more silicon and alloying elements in the form of difficult-to-process carbides.
In high strength cast iron graphite inclusions have the shape of a ball surrounded by a shell of silicon carbide.
On cloudy days cast iron graphite is presented in the form of flakes and is quite easily processed by cutting.
Therefore, when processing high-strength cast iron An impressive amount of heat is released.
Grey cast iron contains carbon in the combined state only partially (no more than 0.5%).
The other carbon is in cast iron V empty state in the form of graphite.
Graphite inclusions make the fracture ashen in color.
How the bend is blacker, the cast iron softer.
Graphite is formed as a result of heat treatment of white cast iron, when part of the cementite breaks down into soft ductile iron and graphite.
Depending on the dominant structure, gray is distinguished cast iron on a pearlite, ferrite or ferrite-perlite basis.
I didn't realize What does it mean “a piece of white cast iron”?!
"White" cast iron can not be.
There is a concept of bleached cast iron— in the surface layer, like a consequence of heat treatment (including casting), carbon burns out and as a result, a layer of high-carbon steel is obtained, which is also heated.
This is why the procedure for stripping cast iron casting pigs is very “painful” for lathes.
It is finally forbidden to do this on high-precision machines.
In production they tend to do this using sandpaper.
However, the bleached layer is quite high (in the pigs I encountered - literally up to 1mm), having passed it, you can cut cast iron pretty easy.
To overcome this difficulty, TaeguTec applies to all its carbide inserts (Fig.
1) assigned for processing cast iron, a rather low multilayer coating (about 20 microns) containing a layer of Al 2 O 3 (aluminum oxide).
Al 2 O 3 oxide protects the base of the carbide plate from overheating.
In addition, aluminum oxide is chemically stable: it does not react with cast iron, What avoids chemical wear of the plate.
Coatings are often practiced in which Al 2 O 3 alternates with low layers of TiCN (titanium carbonitride) (Fig.
As you know, cast iron is a brittle metal, however, cast iron pipes can be cut in several ways. These are the ones that will be discussed in this article.
Cast iron pipes can be cut using a regular hacksaw and chisel.
This work is done in this way. First you need to mark a cutting line on the surface of the pipe. After this, you need to place a wooden board and make a notch several millimeters deep along the entire length of the line. After the notch line is closed, the pipe should be moved to the edge of the board so that the notch hangs over the board. Now you need to insert the chisel blade into the cut and make a sharp blow with a hammer. The end of the cast iron pipe will then fall off smoothly.
In addition, there are special pipe cutters for cutting cast iron pipes. The first step is to install the cutter on the pipe cutter. It is a metal disk with diamond coating on the cutting edge. After this, use the handle to press the pipe tightly. Only after this can you start making cuts. Perhaps the best pipe cutters for cast iron pipes are Exact Pipecut brand pipe cutters. 
You can also cut a cast iron pipe using a grinder. About it in a simple way There is no need to write a lot, since every man already knows how to use this tool. The only thing you need to keep in mind is that to cut cast iron pipes you need to use a Bakelite-based cutting disc. Ceramic bonded discs are not suitable for cast iron pipes.
In addition, there are two methods of gas cutting of cast iron pipes. This is gas-oxygen and oxygen-lance cutting.
The essence of the first method is to expose the pipe to a very thin jet of flame under high pressure. The combustion product here can be a mixture of kerosene with oxygen or a mixture of diesel fuel with oxygen. This method is used in construction, production, and also in the elimination of man-made accidents.
The operating principle of oxygen lance cutting is as follows. As cutting tool a thin tube made of hardened steel is used here. The end of this tube is heated to a temperature of 1350 degrees. This is done using the same gas welding machine or a blowtorch. Then oxygen is supplied through this tube, which ignites and reaches a temperature of two thousand degrees at the outlet. It is the oxygen flame that cuts the pipe.
Pipes made of plastic are used to create pipelines different types due to many advantages - corrosion resistance, low weight, easy installation. Therefore, replacing a cast iron sewer with a plastic one is an excellent solution, but dismantling old pipes is not so easy. This job requires experience using power tools. When replacing, you must follow safety rules. You can see what plastic products look like in the photo.
Advantages plastic pipes:
Do-it-yourself dismantling of a cast iron sewer begins with preparing the tools.
The work is done using:
Before dismantling, determine how the cast iron parts (in particular crosses and tees) were connected to the shaped section, which requires finding the connection point - usually it is located higher than the level flooring. If the floor has tiles or a screed, you will need a hammer drill or chisel to find it. You need to work with them carefully - you must not damage the socket remaining in the ceiling.
The connection between tees, crosses and pipes can be made in three ways:
As for how to dismantle a cast iron sewer, this work takes place in stages:
Its height must correspond to the parameters of the shaped product that is pressed during installation of plastic products. The cut is made relative to a horizontal line, so the location of the cut is pre-marked masking tape. Using a sharp blow directed towards the wall, the pipe is destroyed in the place where the cut was made. Cast iron products are fragile, and problems with this cannot arise.
Replacing a cast iron sewer system with a plastic one with your own hands cannot be called particularly difficult. If the connection of the pipe with the shaped elements is rigid, then to disassemble the structure it is necessary to clear the junction, loosening the product. When the junction of the connecting elements has expanded significantly, you can use a hammer drill with a thin drill that does not have a pobedite tip. They carefully try to chisel the mortar connecting the elements, and remove the remains with a chisel.
Dismantling can be difficult if there is practically no seam, and the solution has glued the elements together too tightly. IN in this case use an old metal sheet to widen the joint. If in the end it was not possible to disassemble the connection, then you should cut off the shaped part 2-3 centimeters above the joint.
The piece of pipe that remains in the socket is cut with a grinder, and the protection is removed at different angles of inclination of the disk. The fragments of shaped products remaining inside the pipes are removed using a special wedge.
There is nothing complicated about how to dismantle an old cast iron sewer. You just need to be patient.
Materials required for replacement:
As for tools, you will need:
When all the materials and tools are prepared, you can move on to how to replace a cast iron drain with a plastic one.
Replacement work sewer riser you should start by inserting a rubber cuff into the socket of the lower section of the pipe. A tee or cross is placed in it, and soap is applied to the end. If suddenly the connection turns out to be loose, then it is sealed using silicone or linen winding (read: “How to connect cast iron sewer pipe with plastic - options and examples").
Pipes are cut to design length, the end should be chamfered or sanded. To accurately determine the length of the product, an expansion pipe is placed into it until it stops. Then the resulting structure is also inserted to the limit into the remainder of the cast iron pipe located in the upper ceiling. The minimum size of the gap that must remain between the tee or cross and the resulting assembly cannot be less than half a centimeter. Pre-assembly is carried out without using rubber gaskets and cuffs.
Regarding how to connect a cast iron sewer with a plastic one, it makes no sense to use pipes instead of sliding couplings for this purpose.
Several fasteners are placed in the wall. If the ceilings have standard height, then three pieces are enough, if they are tall, then 4.
To execute final assembly, install all the required cuffs and gaskets, apply soap to the ends of the products, and connect the pipes. After the final installation of the riser and completion of the clamping of the fastening clamps, the functionality of the sewer system is checked by passing a large volume of water through it. The replacement can be considered finally completed only after the successful completion of the tests.
Considering the fact that plastic riser has less sound insulation than cast iron, then you can install a protective box (read also: “Do-it-yourself noise insulation of a sewer riser”).
There is nothing complicated about how to change a cast-iron sewer system to a plastic one.
You just need to follow the instructions exactly. If you have doubts that you will be able to do this work correctly, you should contact a specialist. Plastic sewerage, subject to correct execution work, will last for decades without requiring repairs. For this reason, if cast iron pipes leak, it is better to immediately replace them with plastic ones.
The most difficult step when replacing an old pipeline is the dismantling of a cast iron pipe that has served its purpose. Previously, when constructing communications, cast iron pipes were used, the connection of which took place cement mortar, gray or aluminum. Pipelines assembled using the last two substances are very difficult to destroy, so you need to prepare for lengthy dismantling work. And this article will tell you about the technology for their implementation.
Laying a new sewer often begins with dismantling the old one
At first it may seem that dismantling outdated communications is a trivial matter, because breaking is not building. However, this requires just the right, qualified approach, because otherwise it is easy to damage the riser connecting several apartments at once. And this is a real disaster, the consequence of which will be the need to replace the common riser and, of course, boundless indignation of the neighbors.
The cast iron pipe should be dismantled carefully, adhering to the following order:
Bathroom after dismantling the toilet
Due to the fact that cast iron is characterized by high fragility, pipes located at some distance from the riser can be easily broken with a hammer.
If the joints of a cast iron pipeline are fastened with sulfur, this greatly complicates the dismantling task.
However, we have some tips on how to disassemble cast iron sewer pipes in this case. Like anything Chemical substance, sulfur is destroyed under certain influences, namely, during prolonged heating with an open flame. High temperatures make it viscous and plastic, making removal of the substance from the surface simple.
Warming up sulfur gas burner
To dismantle a pipeline connected with sulfur, prepare a hammer and chisel, as well as a gas torch for heating. By the way, the burner can be replaced blowtorch.
When the pipeline is heated with a lamp or burner, harmful gas - sulfur dioxide - will be released into the surrounding space. In addition, open fire is also dangerous. Therefore, measures to protect life, health and the environment are mandatory. Operations for heating sulfur can last several hours, so that combustion products do not harm the lungs, you will need a gas mask, and to prevent accidental fire of furniture and other interior elements, it is suitable protective screen made of metal or asbestos.
Cleaning the joint with a screwdriver
It is advisable to begin dismantling by disassembling pipes located at a distance from the riser. This is not difficult and most likely there will be no problems if you use a chisel and a hammer, because cast iron is a very fragile metal.
Due to the fragility of cast iron, it is not recommended to use a hammer with metal attachments when dismantling. With a strong impact, part of the cast iron pipe may end up inside the pipeline, thereby reducing its clearance or forming a serious blockage in the sewer system. Therefore, it is better to use hammers with polymer or plastic heads.
So, let's look at how to remove a cast iron sewer pipe:
Use a hammer to break sections up to the crosspiece
Be especially careful when removing pipes connected to the tee located on the riser. Using a grinder, cut off part of the pipe, leaving a distance of 10 cm to the riser. Loosen the remaining element and try to remove it from the socket.
Pipe dismantled to the riser
Dismantling of the old pipeline must be carried out to the maximum possible extent, since it is better to cut off a cast-iron pipe to the point where it passes into the socket. Then joining a new plastic pipeline and a cast iron pipe will take less time and effort. Don’t think twice about how to cut a cast iron pipe; use a grinder.
How to cut a cast iron pipe if you don’t have an angle grinder? Take a hacksaw and get to work, but this will naturally increase the duration of dismantling operations.
Cutting a cast iron pipe with a grinder
If dismantling attempts are unsuccessful, do not be upset: stores sell adapter couplings specifically designed for connecting cast iron and polymer pipes.
Sometimes it can be difficult to cut plastic pipes. Try to saw it halfway around the circumference, and then apply slight pressure or perform a slight rotation - the pipe will burst.
If the pipe cannot be removed from the socket of the riser, and you no longer know how to remove the cast iron pipe, make cuts in a circle along the pipe at intervals of approximately 20 mm, reaching the socket, and then remove it from the riser.
Before connecting cast iron and polymer pipes, it is necessary to clean the former from sulfur, using the same heating. After removing the sulfur, the pipes are allowed to cool, usually for several hours. At the final stage, the installation of a new sewer network. It is best to purchase pipes from modern materials: plastic or metal-plastic.
