Introduction
The production of hardware is an independent area of metalworking. Hardware is conventionally called a group of industrial metal products widely used in the national economy, for the manufacture of which wire rod, small-section rolled products, calibrated metal, wire and rolled strips are used. This group of products, related to the products of the fourth stage of ferrous metallurgy (considering the first - the production of cast iron, the second - steel, the third - rolled products), includes: wire, rope products, metal cord, twisted reinforcement, metal mesh, fasteners, etc.
Metal processing by drawing, i.e. pulling a workpiece through a hole whose output dimensions are smaller than the original cross-section of the workpiece is widely used in various industries. Products obtained by drawing have high surface quality and high dimensional accuracy of the cross section.
Drawing compares favorably with mechanical processing of metal by cutting (planing), milling, turning, etc., since there is no metal waste in the form of chips, and the process itself is noticeably more productive and less labor-intensive.
Drawing is one of the oldest methods of metal forming. Drawing was first used 3-3.5 thousand years BC. At the beginning of the 18th century, 16 water-driven drawing mills operated at factories in the Urals, producing about 45 tons of iron wire per year. In 1838, repeated drawing at high speeds of 30-60 m/min was used for the first time. In 1922, at the Beloretsk Steel Wire and Rope Plant, a special type of heat treatment of wire rod was introduced - patenting, with the help of which strong steel wire was obtained. The transition from drawing on single machines to drawing on multiple mills has significantly increased productivity. The drawing speed has increased by more than 15 times.
Steel wire production is constantly being improved technically. The production structure has been changed: the share of production of wire for critical purposes, which is thinner and stronger, has been increased. High drawing speeds have been mastered.
The main range of wire is produced using modern, fairly efficient technological schemes on high-performance equipment. Steel wire production is equipped with in-line units that combine heat treatment and surface preparation operations, including the application of metal coatings.
The hardware industry processes 90-95% of the wire rod produced into wire. Along with increasing the strength of the wire and reducing the value of its plus tolerances on the diameter, metal is significantly saved. This is also facilitated by an increase in the share of production of wire with protective coatings and with a shaped cross-section instead of a round one, which makes it possible to reduce the weight of the product itself and all wire consumed.
JSC "ChSPZ" is a large enterprise in the hardware industry, whose product range includes a wide range of hardware. Currently, the share of ChSPZ in the shipment of commercial products among the enterprises of the Prommetiz association is 38%.
On December 30, 1967, an order was issued by the Ministry of Ferrous Metallurgy of the USSR on the creation of the Cherepovets Steel Rolling Plant on the basis of the hardware production that had been withdrawn from the metallurgical plant.
Currently, JSC ChSPZ is divided into three large production facilities:
hardware production as part of steel wire shop No. 1 with a capacity of 450 thousand tons of wire per year; a nailing shop with a capacity of 70 thousand tons of nails per year; metal mesh workshop with a capacity of 30 thousand tons of mesh and mesh structures per year; electrode workshop with a capacity of 66 thousand tons of electrodes and flux-cored wire per year;
calibration production as part of a calibration shop with a capacity of 500 thousand tons of calibrated metal per year; fastening workshop with a capacity of 15 thousand tons of fasteners per year; workshops for steel shaped profiles with a capacity of 20 thousand tons of shaped profiles per year;
steel wire and rope production consisting of steel wire shop No. 2 with a capacity of 120 thousand tons of wire per year and a rope shop with a capacity of 75 thousand tons of steel and reinforcing ropes per year.
The structure of the plant includes a number of services and auxiliary workshops: power shop, tool shop, mechanical repair shop, container shop, construction shop, transport and cargo shop, etc. Providing production with raw materials and materials is carried out by the Directorate for Providing Material and Technical Resources, the Directorate for Marketing and Sales carries out the work with clients, sales planning and market research.
Used information from the “Drawer's Manual”.
1. Classification of drawing mills
A drawing mill is a machine used for processing metal by drawing , .i.e., drawing metal blanks in a cold state through a drawing tool to obtain smaller cross-sectional dimensions of the finished product - wire. Drawing processes wire of round and shaped sections and ensures high profile accuracy and a clean, smooth surface. During cold drawing, the yield strength and strength, as well as the hardness of the drawn metal, significantly increase.
Depending on the design features and purpose, drawing mills are divided into two groups: mills with circular movement of the wire when winding on a drum and with rectilinear movement of the finished product using pulling carts. According to the principle of operation, drawing mills are classified into drawing mills without wire sliding on traction drums and mills with wire sliding on drums, except for the last one, finishing.
The former, in turn, are divided into mills with wire accumulation on intermediate drums and into mills with automatic control of the speed of rotation of intermediate drums on straight-through mills.
According to the multiplicity of drawing, drawing mills are divided into
single and multiple. According to the kinematic principle - mills with individual drive of each drum and mills with group drive of all drums. Depending on the diameter of the drawn wire, the mills are divided into: for particularly thick drawing (with a wire diameter of more than 6.0 mm), coarse drawing (3.0-6.0 mm), medium drawing (1.8-3.0 mm), fine drawing (0.8-1.8 mm), very fine drawing (0.5-0.8 mm), the finest drawing (0.1-0.5 mm) and drawing wire with a diameter of less than 0.1 mm.
According to the thermal conditions of deformation, wire drawing is divided into:
hot drawing - drawing under conditions of post-recrystallization temperatures (up to 900°C), used for metals such as tungsten, molybdenum, titanium and aluminum alloys, since they have insufficient ductility at normal temperatures and exhibit brittleness; warm drawing - drawing under conditions up to or near the recrystallization order (up to 500°C), used for drawing wire from high-speed steel grades such as R-9, R-18; low-temperature drawing - drawing in the temperature range from 60°C to 180°C, used in the production of wire from high-alloy steels with an austenitic and austenitic-ferritic structure.
In addition, the drawing process can be carried out with counter-tension, as happens on direct-flow drawing mills - before the corresponding fibers of the drawn wire, a preliminary tension is created from the previous drum.
Vibratory drawing- drawing with vibration applied to the wire or die with a frequency of 200 to 1000 Hz, which leads to a reduction in drawing force by 35-45%.
Drawing through the rotating die also reduces the drawing force, but a special drive is required to rotate the die.
Wire drawing through non-driven roller dies, used for high-strength steels, similar to pressure rolling with non-driven rolls.
Appearance in 1927-28 carbide drawing tools made a kind of revolution in drawing production.
1.1 Drawing mills for one-time wire drawing
Single-shot drawing machines are designed for drawing wire from workpieces of thick sizes - from 8.0 to 20.0 mm. The diameter of the pulling drums is 550-750 mm.
The operating diagram of a single drawing mill is shown in Fig. 1.1. The drawn workpiece 2 is unwound from the unwinding device 1. After passing through the drawing tool (die) 3, the wire 4 drawn to the required size (diameter) is wound onto the pulling drum b, which is driven into rotation by the electric motor 7 through a gearbox or gearbox 6.
The drawing mill (Fig. 1.2) is an independent unit consisting of a cast body 11 on which a traction drawing drum 5 is mounted. The drum receives rotation from an electric drive consisting of an electric motor 3, a V-belt drive, a four-speed gearbox 4, bevel and cylindrical gear pairs wheels
The bundle of the workpiece to be drawn is put on the console 1 or figure 2. The end of the wire, after being sharpened on a sharpening machine, is passed through the hole in the die 9, after which it is grabbed with drawing pliers. The pliers are connected to drum 5 using a plate chain with a hook at the other end. At filling (slow) speed, several turns of wire are wound onto the drum, after which the pliers are removed, and the free end of the wire is secured to the spoke 6 of the drum. After this, the mill is switched on to operating speed.
After accumulating a certain number of turns of wire on the drum, the mill stops, the resulting coil of wire (or a workpiece) is removed and placed on the tying figure 8.
All operations for laying a coil of workpiece on an unwinding device and removing a coil of wire are mechanized.
The drawing drum is served by lifts, and the coil is laid by a telpher 7. The weight of the coils from wire rolling mills is 1.0-1.5 tons; for their enlargement, butt welding is used using special welding machines 10, with which each mill is equipped.
Wire can be wound not only into coils, but also into coils with a capacity of up to 2.0 tons using special winding devices that can be installed in line with drawing machines. This allows you to increase the productivity of the drawing mill by reducing the time for manual operations (removing a coil of wire from the drum, etc.) and increasing machine time. At the same time, the quality of the finished product improves, waste is reduced, wire tangling is eliminated, etc.
The drive in single drawing mills can be carried out from electric motors of both alternating and direct current.
The drive must provide:
starting the mill when refueling at a slow, creeping speed and smooth acceleration, eliminating wire breakage;
fast acceleration for maximum performance;
wide range of drawing speed control depending on the cross-sectional size and grade of the material being drawn;
quick shutdown of the mill in emergency situations.
Although modern one-shot mills are designed to operate at higher drawing speeds, they have the following disadvantages:
for one, and sometimes for two broaches (with a stepped, double drum) it is impossible to obtain high reductions;
the limited drawing speed is entirely determined by the permissible speed of the workpiece coming off the figure;
Due to the fact that the diameter of the workpiece is quite large, and the machine time for one reel of the workpiece is small, the mill often has to be stopped to replace the reel, as well as to remove a coil of wire if the latter accumulates on the drum.
Single-shot drawing machines are widely used for the production of wire of shaped profiles (sections), for drawing hard-to-deform steel grades, for calibrating thick wire, as well as for warm drawing with preheating of the metal (workpiece).
Table 2.1 shows the technical characteristics of the most common types of drawing mills for both single and multiple drawing of the VNIIMETMASH design.
Kinematic diagrams of the drives of the VSM 1/650, VSM 1/550 and VSM 1/750 mills are shown in Fig. 1.3-1.5.
Fig.1.1. Scheme of operation of a single drawing mill:
1 - unwinding device; 2 - wire - blank; 3 - drawing tool; 4 - stretched wire; 5 - pulling drum; 6 - gearbox; 7 - electric motor
Fig.1.2. General view of the VSM 1/650 drawing machine:
1-console for blanks in skeins; 2-rotating figures for skeins; 3-electric drive motor; 4-gearbox; 5-drawing, pulling drum; 6-spokes for storing wire; 7-column puller: 8-figure for tying the skein; 9-die holder; 10-welding machine; 11-body of the mill block; 12-electrical cabinet; 13-emery
. 1.2 Drawing countries for repeated drawing
wire
On multiple drawing mills, the wire - the workpiece passes sequentially through several dies, changing after each
Drawing machine type UDZSA 5000/6
A six-fold block-type drawing machine model UDZSA 5000/6 with a maximum drawing force on the first roughing block equal to 50 kN (5000 kg), is designed for drawing carbon steel wire with a workpiece diameter of up to 12 mm. When drawing copper or aluminum wire, the diameter of the workpiece may be larger. The general view of the UDZSA 5000/6 drawing machine is shown in Fig. 3.1.
All blocks of this mill have the same design. A distinctive feature is the finishing drum, equipped with special knitting needles for collecting turns of finished wire into a skein. If the drawing machine is equipped with a winding apparatus, then the finished wire is wound onto reels with a capacity of up to 1000 kg.
Each block is installed on its own reinforced concrete foundation and firmly attached to it with anchor bolts. The necessary communications are supplied to the blocks: pipelines for water cooling of drums and fiber holders, power supply, control systems, etc.
Depending on the technological features of wire manufacturing and obtaining the necessary mechanical properties on the finished size, drawing mills can be equipped in one line with a different number of blocks (from one to six). Main technical characteristics of drawing mills UDZSA 5000/1-6, 2500/1-6, 1250/1-10 and 630/1-10 are given in Table 3.2.
The blocks of the UDZSA 5000/6 drawing mill include a drive from an AC electric motor, a V-belt drive, a four-speed gearbox, two cylindrical and one bevel gears, shown in Fig. 3.2. All mechanisms are installed in a cast steel housing, providing sufficient strength and rigidity. The gear shafts are supported on rolling bearings. Lubrication of gears and bearing units - crankcase, dipping and splashing. To increase durability, wheel teeth are subjected to hardening and grinding or lapping. Differential rollers operating under heavy load conditions are also hardened by hardening.
Each drawing machine is equipped with a threading collet for pulling the end of the wire through the drawing tool and winding several turns of wire onto the drum for further drawing. The other end of the collet has a hook that hooks into special holes in the drum. After winding several turns of wire (about 10), the collet is removed and the mill is switched on from threading speed to normal operating speed. When refueling, you need to be very careful and protect your hands from possible tightening of the coils of the wound wire.
A general view of the intermediate drum of the UDZSA 5000/p drawing machine is shown in Fig. 3.2.
A workpiece or wire of intermediate size, passing through a drawing tool installed in the draw holder 10, is wound onto a traction drum and, after accumulating a certain volume, is passed through the roller 13 of the brake differential and then through the guide block 14 mounted on a vertical stand to the draw holder of the next block of the drawing mill.
The drawing mill block is turned on using button 9.. “Start”, and stopping with button 8 “Stop”. The drawing tool cooling system is controlled by bypass valve 7, and the drum is cooled by valve 6.
While threading the wire on the drum and setting up the mill, the foot switch for the “creeping” slow speed of the block drive is the limit switch 1. The rotation speed of the drum is controlled by the tachogenerator 2.
Switching gear stages of the gearbox on the block is carried out by levers 16 and 17, and at the same time the same speed (gear) is set on all blocks. The increase in the linear drawing speed or the peripheral speed of the drums from the first to the last finishing is carried out due to the different number of teeth Za and Zb in the kinematic scheme in each block.
Blocking contact 15 switches off the main drive motor when the protection door is open. All mechanisms are mounted on a cast housing 18.
In Fig. 3.3 shows the kinematic diagram of one block of the UDZSA 5000/6 drawing mill, and table. 3.3 - number data
Rice. 3.2. General view of the drawing machine block UDZSA 5000/p: 1 - foot button “Stop”; 2 - tachogenerator; 3 - electric motor; 4 - main drive electric motor; 5 - electrical terminal box; 6 - bypass valve for cooling the drum; 7 - bypass valve for cooling the tool; 8 - "Stop" button; 9 - "Start" button; 10 - guide roller in front of the die holder; 11 - coolant tank cover; 12 - pulling drum; 13 - differential brake; 14 - upper guide roller; 15 - blocking contact when opening the protective fence; 16 - lever for engaging 2nd and 4th gears; 17 - lever for engaging 1st and 3rd gears; 18 - block body
1.3 Drawing mills divided into two types : drum and chain.
Rice. 1.3.1. Longitudinal section of the die (a) and diagrams of the drum (b) and chain (c) drawing mills
Drum mills (Fig. 1.3.1, b) are used for drawing wire and pipes of small diameter, wound on a turntable 1. The pre-sharpened end of the wire is passed through the hole in the draw 2 and secured to the drum 3, which is driven into rotation by an electric motor through a gearbox and gear 4 There are also multiple drawing mills that have up to 20 drums with dies installed in front of each of them.
Chain mills with the rectilinear movement of the pulling device (Fig. 1.3.1, c) is used for drawing rods and pipes that cannot be wound into coils. In this mill, the end of the rod is passed through the hole in the die 2 and grabbed by pliers 5, which are attached to the carriage 6. The carriage is moved through the traction hook 7 by a plate chain 8 driven by a sprocket 9, which rotates from an electric motor 11 through a gearbox 10.
Drawing, as a rule, is carried out in a cold state, and therefore it is accompanied by hardening (hardening) of the metal. The starting materials are rolled or pressed rods and pipes made of steel, non-ferrous metals and their alloys. The amount of deformation in one pass is limited: = 1.25-1.45. If large deformation is required to obtain the required profiles, then drawing is used in several transitions by pulling through a series of holes gradually decreasing in size. To remove hardening, after each transition the metal is subjected to intermediate annealing. To reduce the friction force of the metal on the tool, the hole in the die is polished and various lubricants are used - mineral oils, drying oil, graphite, talc, soaps, phosphate and metal coatings, etc.
The range of products made by drawing is very diverse: wire 0.002-10 mm and shaped profiles (Fig. 1.3.1, b), pipes with a diameter of 0.3 to 500 mm with a wall thickness of 0.05 to 5-6 mm.
Rice. 3.47. Scheme of pipe drawing (a) and examples of profiles obtained by drawing (b)
Pipe drawing can be done without a mandrel to reduce only the outer diameter (reduction), and with a mandrel (to reduce the outer diameter and wall thickness). In Fig. 3.47, a, shows a diagram of drawing pipe 1 on a long fixed mandrel 3. In this case, the profile of the resulting pipe is determined by the gap between the die 2 and mandrel 3. Drawing ensures high dimensional accuracy (steel wire with a diameter of 1.0-1.6 mm has a tolerance of 0 .02 mm), high surface quality, obtaining very thin profiles. The method makes it possible to widely vary (due to cold hardening, as well as heat treatment) the range of strength and plastic properties of the metal of the finished product, dramatically reduces waste and increases productivity. A distinctive feature of the drawing process is its versatility (ease and speed of tool replacement), which makes it very common.
Unwinding devices are designed for unwinding the wire blank in front of the drawing mill for the purpose of its subsequent drawing. Depending on the form in which the wire is supplied for further processing: in coils (bundles) or on large-capacity spools (up to 1000 kg or more), unwinding devices are structurally divided into three types:
unwinding with rotating figures;
unwinding with permanently installed brackets, consoles;
unwinding with quill type devices for installing coils.
The requirements for unwinding devices are:
ensuring uniform descent of the workpiece wire without tangling and at a certain angle;
the ability to regulate the tension force depending on the wire diameter;
the ability to weld wire ends without stopping the drawing mill;
ensuring safe work of maintenance personnel;
mechanization of loading unwinding devices;
the possibility of using high speeds of wire coming out of unwinding devices to ensure high-speed and high-speed wire drawing.
When unwinding wire from coils laid on a rotating figurine, a positive advantage is that the wire, unwinding from the figurine, does not twist around its axis, which is important when drawing shaped wire along the cross-section. But with large masses of the skein and a high frequency of rotation of the figurine, due to inaccurate balancing of the skein relative to the axis of rotation, large centrifugal inertial forces arise, which cause rapid wear of the bearing supports, and, consequently, their frequent repairs. Rotating devices can unwind thick and medium-sized wire. Welding the ends of the wire without stopping the figure, and therefore the drawing machine, is impossible, so the time spent on manual operations increases.
When installing coils of wire on brackets, it is possible to weld the ends of the wire while the mill is running. But with this method of unwinding, the wire, leaving the bracket, receives an axial twist for each turn by one full turn, i.e. at 360°. The wire approaches the first wire holder of the mill in a corrugated form. To reduce the degree of waviness, the brackets are mounted at a much greater distance than the rotating figures from the drawing machine, which increases the production area.
To prevent the coils from spontaneously coming off and getting tangled, a special lever is installed on the bracket, which holds the coils by the force of its own mass. The lower arm also prevents random wheel alignment. Each removed turn lifts the levers and, hitting their supports, they make a knocking sound. Several of these operating unwinders create additional noise in the workshop in the form of periodic impacts.
The decoiler in the form of a suspension for two coils is simultaneously transported by a crane or crane beam from the department for preparing the wire surface for drawing to the drawing department. The total load capacity of the suspension is up to 1.5 tons. While unwinding is going on from one suspension, the end of the coil is being prepared on the second for welding with the rear end of the first coil.
Unwinding wire from a reel is currently the most widespread and, where possible, replaces unwinding from coils. Since the mass of wire on high-capacity spools is several times greater than the mass of the coil, the manual time required to replace the workpiece is significantly reduced. The conditions for transportation and storage of wire are improved, the possibility of entanglement of turns is reduced, and, consequently, metal waste is reduced. Almost any rewinding speed required for drawing is possible, and the operation of the unwinding device is silent.
The unwinding device has two independent stands with rotating quills. One of the quills must have movement
along its axis to ensure installation of coils of different widths. So, for example, one unwinding device can use reels of sizes 630, 800 and 1000 mm in disk diameter. For heavy-duty reels, lifting devices are provided, usually of the hydraulic type. To ensure braking of the coils, to create tension on the descending wire, there is a block or tape type braking device, which allows you to adjust the tension force of the wire depending on its diameter.
In some cases, friction braking systems do not operate smoothly or consistently. Therefore, in these cases, an electric motor is installed as a brake, operating in generator mode and creating smooth braking. The amount of load on the electric motor-generator can be used to widely regulate the tension force of the wire unwinding from the reel.
An important element of unwinding devices, especially from coils, is the presence of limit switches designed to turn off the drawing mill in the event of tangling of the wire turns and its tightening, as well as when the end of the wire coil. They are installed between the unwinding device and the drawing machine.
The limit switch is controlled by a rotary lever-bracket through which the wire is passed. On some drawing mills, loop compensators are installed, which, by lengthening or shortening the wire loop, coordinate the operation of the unwinding device with the drawing mill, also preventing wire breakage.
On the working platform of the unwinding devices, scissors are installed to trim the ends before welding. Wire of thin and medium diameters can be cut with mechanical scissors mounted on cutting machines. For thicker diameters from 0.8 mm and more, hydraulically driven shears with a cutting force of up to 150 kN (15 tf), having an autonomous station with all the necessary equipment, have proven themselves in operation. The working pressure in the hydraulic system reaches 16 MPa (160 kgf/cm2).
Unwinding devices from reelsAVS 630T and AVS 800T
Unwinding devices of the indicated types are designed for unwinding the blank wire before the drawing machine from coils with a diameter of 315-630 mm for AVS 630T and with a diameter of 500-800 mm for AVS 800T. The maximum permissible wire weight for the first device is up to 700 kg, and for the second - up to 1200 kg.
In the welded body 1 (Fig. 2.1) there are two lever supports 5 and 7. The supports move translationally along axis 4 using a lead screw 6 with left and right threads, rotating manually from the steering wheel 3. The clamping cones 9 have a special shape that takes into account the dimensions of the holes of the coils various diameters. To lift the coils from the frame, after clamping them with cones, an eccentric mechanism 2 is used, driven by a handle-lever 8. By lowering the lever to a horizontal position, the coil is installed in the working position. A brake pulley 10 is installed on one of the cones, operating on the principle of a band brake, and the tension of the descending workpiece is adjusted using a T-shaped screw.
Fig.2.1. Unwinder AVS 630T and AVS 800T
Winding machines for drawing mills
Winding machines, installed in line with drawing machines, are designed for winding finished size wire onto large capacity spools: 250, 500 and 1000 kg, and sometimes more. Due to the large capacity of the coil compared to the mass of the coil on the finishing drum of the drawing mill, which usually does not exceed 70-80 kg, the productivity of the mill increases by reducing the number of stops to remove the finished wire, i.e. the share of machine time increases and the time for manual operations decreases.
The wound wire on reels is easily unwound without tangling during subsequent technological processes, for example, when rewinding wire onto charging reels in rope shops. As a result, the amount of waste during rewinding is reduced.
On block-type mills, winding devices are independent units, the operation of which must be strictly coordinated with the operation of the drawing mill; more precisely, the speed of winding the wire onto the reel must be synchronized with the speed of its movement from the finishing drum.
Winding machines, as independent units, have individual drives, which should provide a wide range of winding speeds in accordance with the wire drawing speeds on the drawing mill. The drive of the winding apparatus must ensure constant and uniform tension of the wire as it is wound onto the reel and as the diameter of the winding increases. During the start-up of the drawing mill, there should be no slack in the wire, otherwise the wire turns will slip on the finishing drum of the drawing mill and, as a result, the wire will break. Likewise, when stopping the mill or braking, there should not be excessive tension in the wire between the spool and the finishing drum.
Metalworking is a high-tech process. To obtain competitive products, it is necessary to use high-quality equipment. One of the types of equipment that is used at a metalworking enterprise is drawing machines. There are different types of this equipment. The features of drawing units will be discussed further.
Drawing machines are special equipment that is used during metal forming. They can be used to obtain different products. The operating principle of drawing mills is quite simple. A workpiece of a certain diameter is pulled through a hole of a smaller diameter. This work is done by rollers. They give the workpiece not only the required diameter, but also the shape.
As a result, the metal stretches and becomes thinner. The cross-section of the product is round or shaped. The profile is highly accurate. Its surface is characterized by high purity. During metal processing, the workpiece may heat up. There is also cold drawing. The second option has several advantages. The finished product is stronger and harder. At the same time, the yield strength of its material increases.
Drawing is of great importance in metalworking. Drawing machines make it possible to produce wire with a diameter of up to 5 microns. Pipes are also produced using similar equipment. Their maximum diameter is 40 cm. The products of this branch of production are widely used in the national economy and industry.
Modern drawing equipment has a number of distinctive features. Modern technologies are used in metal processing. Therefore, today's mills are significantly different from the equipment of past decades. First of all, their productivity increases. Modern mills are capable of producing much more products per unit of time. In this case, the quality of the metal surface will be good.
The new equipment is produced complete with dies, which are characterized by significant resistance to adverse influences and a long service life. Also, modern units provide different degrees of protection. This significantly increases the safety of workers when operating the equipment. The processing accuracy is ensured by modern measuring devices included in the design.
Modern wire drawing machines include functional structure and auxiliary equipment. The main part of the structure is responsible for obtaining a certain processing result. Depending on the pulling device, the target area of the mill is determined. The equipment can pull the workpiece in a straight line or wind it onto a drum. In the first case, several types of aggregates are distinguished. They can be track-type, rack-and-pinion, or reciprocating. Also on sale are units with a hydraulic mechanism for drawing the workpiece, and chain drawing machines.
Also on sale is equipment with the function of winding the processed material onto a drum.
On equipment that involves drawing the workpiece in a straight line, rods, pipes, and other similar products are produced. They don't go into riots.
Techniques with a wire winding function are used for It can have a special profile. Also, pipes with a minimum diameter are made on such machines.
The presented equipment can be of the following types:
For each type of finished product, the most suitable production method is selected. During production, various metals and alloys are used. The production technology of the product depends on their type. The procedure includes several sequential steps.
A drawing mill for the production of copper wire, steel pipes or other products necessarily includes a number of auxiliary mechanisms. It is intended to ensure the normal flow of the production process. This category includes unwinders, lubrication equipment, and rewinders. This category of mechanisms also includes devices for sharpening wire, packing coils, and cutting workpieces. In some cases, the material passing through the main equipment requires processing by welding.
In addition to drawing equipment, the equipment may include a drum. The movement is carried out using an electric motor and gearbox. The design of one or another may differ depending on what material will be processed on them. Equipment for steel has a number of differences from units for non-ferrous metals. However, modern manufacturers produce equipment that is very similar, regardless of the type of metal.
It should be noted that its functionality depends on what material is processed on the machine. Non-ferrous metals are softer than steel. Therefore, the equipment that pulls them has a sliding function. In this case, it is possible to reduce losses due to friction.
It is necessary to consider in detail the principle of operation of the drawing mill. The material is fed into the unit from the receiving compartment basket. It passes through a series of roller devices. They direct the movement of the workpiece. Thanks to this action, the material is fed to the carriage roller. This is a compensating type device. After this, the workpiece goes to the drawing mill.
The presence of a compensating carriage in the system is extremely important. This helps prevent material breakage. Such a nuisance could not have been avoided by a sudden stop or braking of the line. The operation of the carriage is quite simple. If the equipment stops abruptly for some reason, this device will continue to rotate the rollers for some time. This allows you to dispense some more material.
The compensating type carriage carries out an upward movement at this time. This allows a certain amount of material to be released. It enters the drawing device. In this case, breaking the workpiece becomes impossible.
Next, the material enters the lower double drum. The reversible roller ensures that the material is carried higher. Here the upper drum receives it. If provided for by the mechanism, the finished product is wound onto the rod and stored here. It is from here that the material is supplied when the mill stops, if it stops abruptly.
If necessary, after drawing, the products are straightened. It is given the necessary configuration. All work is provided by an electric motor.
Today, the market for special equipment offers a huge selection of drawing equipment. It is distinguished by functionality, performance and quality. In our country, equipment most often purchased is Russian, Chinese and European.
It is important to contact trusted suppliers. They will provide the necessary documentation for such devices. In this case, the equipment will have a warranty. Manufacturers of drawing mills from Europe stand out in this area. They produce the most modern, innovative equipment. It provides many additional functions and modes. This can be either single mills or entire production lines. The quality of the finished product in this case will be the highest. This ensures that the products are the most competitive.
Among European manufacturers of drawing mills, equipment made in Germany and Switzerland is in great demand. Depending on the type of equipment, the minimum cost of the units is 1.5 million rubles. The most famous manufacturer from Germany in our country is the company Sket. Swiss-made equipment is no less popular. It is supplied to our country by the ENCE company.
For those enterprises that have a limited budget for updating fixed assets, it is possible to modernize technical equipment using drawing mills from China. A huge amount of such equipment is produced in this country. The minimum cost is from 1 million rubles.
Domestic manufacturers also supply similar units to the market. The cost of their products is comparable to Chinese ones. But the quality of mills assembled in Russia is higher. Also, some industries buy equipment that has been used. The price of such units starts from 50 thousand rubles. However, in this case you should not count on long-term operation of the equipment and high quality of the finished product.
There are different types of drawing mills on sale. They are intended for use in various technological processes. One of the popular types of products is a single-pass mill. They allow the production of wire with a round cross-sectional diameter and a size from 25 to 40 mm. Also, similar units produce pipes from ferrous and non-ferrous metals. The larger the diameter of the finished product, the larger the drum installed in the structure.
This type of wire drawing machine winds the wire onto a drum in a single row. This reduces the weight of the rebellion.
Single-shot mills provide a force of 0.05-200 kN. Its choice depends on the type of finished product. In this case, its cross-section, quality and profile are taken into account. Modern high-performance mills of the presented type provide drawing speeds of up to 5 m/s.
Productivity can be increased by increasing the mass of the riot. Moreover, this procedure is carried out both from the unwinding and winding side of the material. To do this, they resort to a process such as welding.
Single-shot drawing provides equipment that includes an electric motor, gearbox, gearbox, unwinding figure, lifter, sharpening section and rack. The equipment stops only if it is necessary to change the receiving device when it is full. This procedure requires very little time. Maintenance and repair of drawing mills of this type is carried out only by specially trained personnel. The procedure does not take much time.
The wire drawing machine can crimp the workpiece twice. This allows you to give the workpiece the required shape and size. Such equipment is used in enterprises with a small volume of metal forming. During such processing, the material is subjected to fourfold compression.
The simple design includes a two-stage drum. At the first stage it has a smaller diameter. The workpiece sliding function is often used here. In this case, the hood should be 1-2% greater than the difference in the diameters of these steps. At the lower stage it is impossible to provide high compression. Therefore, to avoid wire breaks, the sliding function is used here.
Differential double drawing mills are also on sale. They do not involve the use of sliding on both stages. In this case, it is possible to carry out both high and low compressions. Two drawing drums in such a device are located on the same axis.
Drawing machines can crimp the workpiece several times. In this case, the material is pulled simultaneously through several dies. This allows you to increase the degree of elongation of the workpiece. The dies are sequentially located on the production line.
During processing, the drawing ratio is determined. This indicator is influenced by the initial size of the workpiece, its type of section and the parameters of the final product. The multiplicity can be set in the range from 2 to 25. There are mills that provide an even greater value for this indicator.
It is especially difficult to pull strong materials. In this case, there may not be enough tension behind the last wire. Therefore, it is problematic to pull the material through all the line dies at the same time. To make such processing possible, a pulling drum is installed after each die. The workpiece is wound onto it, and then proceeds to the next stage of processing.
Drawing machines of the loopless type involve winding only a few turns of the finished product (6-10 pcs.) onto a drum. This is quite enough to provide the required friction force. In this case, the strip is pulled along the line without slipping. Transportation is carried out without rollers.
Electric motors create counter-tension. The absence of a large number of rollers greatly simplifies the maintenance procedure and filling the mill during drawing of strong, thick workpieces. If the wire cannot be subjected to significant reduction, this type of mill will produce high quality products using counter-tension.
The line's drums are equipped with personal electric drives. They are connected in series. In this case, in the process of adjusting the torque, its excess determines the counter-tension indicator. The speed can only be adjusted on the drum that feeds the finished wire. The remaining elements are configured automatically.
Having examined the features and types of drawing mills, you can understand the principle of their operation, as well as the features of using such equipment in production processes.
1. Brief description of the workshop
TsLP No. 11 is an independent structural division of steel wire and rope production, belongs to the main workshops and specializes in the production of wire from high-alloy, alloyed, carbon, corrosion-resistant, heat-resistant, precision steel grades of various diameters, steel in rods with special surface finishing, profiles from alloyed, carbon and stainless steel grades, nails.
The alloy wire workshop produces about 50% of the products in tonnage and monetary terms produced by BMK; in addition to finished products, the workshop produces semi-finished products for workshops:
For workshop No. 10 - blanks for micron stainless steel grades and resistance alloys;
For workshop No. 12 - a blank for a cigarette lighter ribbon;
For workshop No. 4, No. 5, No. 3 - blanks for ropes.
The CLP No. 11 includes the following sections:
Pickling section, SHS section, drawing section No. 1, drawing section No. 2, thermal section No. 1, thermal section No. 2, TCA No. 4, stabilization line, hardware section, product sorting and packaging section, laboratory, CTRO (electric vehicle repair section , section for installation and small mechanization, mechanical workshops, section for repair of electrical equipment of PLP, section for repair of mechanical and electrical equipment of cranes and elevators, section for repair of plumbing equipment GOSHCH, section for repair of ventilation and gas equipment), crane operators, section for household works .
TsLP No. 11 is intended for the production of wire of alloy steel grades. The workshop produces 120 grades of steel with a diameter from 0.3 to 12.0 mm.
TsLP No. 11 does not have separate funding and is not a legal entity. The workshop is allocated the ownership and use of fixed assets and material resources necessary to complete the tasks assigned to the workshop.
2. Technological process of the workshop
To carry out the process of drawing wire, steel of various types according to steel grades and a wide range of sizes, drum drawing mills of various types are used. All of them, regardless of their division into various groups according to the method of drawing, the size of the drawn wire and other design features of the condition, consist of the following main components: a drawing drum that creates the drawing force, an electric drive to it, consisting of a gearbox through which rotation is supplied from the electric motor to the drum, DC or AC drive motor coupled to the gearbox via an elastic coupling or V-belt drive, control station panel and control panel
This is the composition of the main components of the mill with an individual electric drive for each drum.
In a group electric drive, the transmission of rotation from the electric motor to all drums of the mill is carried out through a common transmission, while the electric drive includes: a drive electric motor, a device that transmits movement from the transmission electric motor, and an electric drive control panel. The transmission device is part of the mill.
Based on the multiplicity, these mills are divided into single drawing and multiple drawing mills. Single drawing mills are used mainly for drawing particularly thick wire (6 mm or more) by pulling it through only one die and simultaneously winding it onto a drawing drum, from which it is then removed in the form of a finished coil, transferred to the next broach.
Multiple drawing mills make it possible to carry out the drawing process simultaneously through several dies with successively decreasing sizes of their holes, which makes it possible to sharply increase the drawing speed, especially on the last drums along the wire movement, and to achieve large total reductions. In this case, there is no need to remove the coil from the traction drum after each drawing and subsequently transfer it to the unwinder for the next broach, as is done on single drawing mills.
On these mills, wire drawing of almost all sizes is carried out, ranging from thick (6 mm) to microwire.
In the hardware production there are a large number of multiple drum drawing mills of various designs of domestic and foreign production, which according to the drawing method can be divided into the following groups
1) Mills operating without changing the stock of wire on intermediate drums with automatic control of the speeds of intermediate drums, with sliding of wire on intermediate drums.
2) Mills operating with a change in the supply of wire on intermediate drums.
3. Technological operating mode of the drawing machine
All elements that make up the electric drive, namely the electric motor, the mechanism for transmitting motion from the electric motor to the drums (pulleys in sliding mills), the equipment and control circuit for the operation of the electric motor must satisfy the following basic requirements arising from the technology of the drawing process.
1) During the period of refueling the mill, associated with the initial operations of pulling the wire through the hole of the die and winding it onto the drum, the speed should be significantly lower than the operating speed and not exceed 0-20 m/s in order to avoid possible wire breaks, pull-out pullouts ticks, accidents with service personnel.
It should be taken into account that the drawing force during the threading period is significantly higher than the drawing force during steady-state drawing at operating speed and in some cases can exceed the tensile strength of the drawn wire, causing it to break. For the same reasons, acceleration of the engine from rest to filling speed must be carried out smoothly. The engine is controlled in refueling mode using the refueling speed button. In this case, the engine runs only when this button is pressed and stops as soon as it is released. For ease of refueling, the location of the said button should allow foot control.
2) The transition to the operating drawing speed must be carried out smoothly in order to avoid possible wire breakage and the necessary labor-intensive reloading of the mill and a decrease in its productivity due to loss of time.
The system for setting and regulating the operating speed should allow for stepless regulation in the range determined by the assortment of steel grades and sizes of wire to be drawn on a given mill, and the design parameters of the drawing process (speed, shortness, single and total reductions!.
In mills, it is necessary to provide electrical interlocks that exclude the possibility of starting the mill at operating speed with open protective shields or grilles.
3) The stop of the mill caused by the end of a given drawing program should be carried out automatically using a set length counter or a wire reel fill switch, and it should be possible to stop the mill using control buttons at any intermediate stages of winding. To stop the mill due to the appearance of malfunctions during the drawing process, leading to disruption of the drawing process, damage to equipment and a threat to the safety of operating personnel, it is necessary to provide automatic shutdown devices that ensure a quick stop of the mill. To ensure reliable and economical operation of the electric drive and the required productivity of the mill itself, the power of its drive electric motors must correspond to the required power, determined on the basis of the specified parameters of the drawing process for a given mill.
All electric drive controls of the mill must ensure convenient, reliable and safe maintenance during refueling, transition to a steady state of drawing at operating speed, when stopping, as well as during repairs and inspections
4. Electrical workshop equipment
Duty desk with documentation, drilling machine, sanding machine, workbench, stands - 2 pcs. , duty cabinet, stands with various documentation LB-40 - lighting.
5. Repair kit and accessories used by electricians
Set of wrenches, screwdriver, pliers, indicator, tester.
6. Methods of sewerage of electricity
Busbar and cable are laid in shafts, or along busbars along the wall
7.Organization of maintenance and repair of electronic equipment
Operational maintenance is carried out by a team of dept. electricians, headed by a foreman. The personnel should be 4 groups, up to 1000V - 3g. Permanent staff must undergo training, have a group and an order. Responsibilities of the duty officer: maintain assigned equipment, quickly eliminate malfunctions, reduce downtime, save energy, carry out tasks, make walk-throughs and inspections, comply with OSH Rules, internal regulations, monitor lighting, follow restrictions on restrictions, keep assigned equipment clean and workplace.
Maintenance is carried out according to schedules, plans, activities. For output to the cap. repair: defective lists, estimates, repair schedules are drawn up, spare parts are procured, technical documentation is drawn up, tools and fixtures are stocked, workplaces are prepared. Equipment after repair must be tested in accordance with the Standards; load test for 24 hours, a report is drawn up, an entry is made in the unit logs.
8. Payment system
Time-based bonus with tariff rate.
9. Documentation at the electrician’s workplace
Operational journal, time sheet, journal of orders and orders.
10. Documentation of the person responsible for electrical equipment
Order on the appointment of persons responsible for the electrical facilities of the plant and structural divisions, and persons replacing them.
Order on the delineation of networks according to balance sheet ownership and operational responsibility between the structural divisions of the plant.
Order on organizing a commission to test the knowledge of electrical and electrical engineering personnel.
An order to assign an experienced employee and admission to an internship within the organization (for managers and specialists) or within a structural unit (for workers).
Order for admission to duplication for operational personnel in the organization (for managers and specialists) or in the structural unit (for workers)
Order for admission to independent work for administrative and maintenance personnel of the organization (for managers and specialists) of the structural unit (worker).
Order on the appointment of a responsible employee for testing and inspection of hand-held electric and portable electric lamps.
Order for an employee from among the electrical technical personnel who has the right to assign 1 qualification group for electronics
Lists of employees who have the right to carry out operational switching, conducting operational negotiations, individual
List of employees who have the right to issue orders or orders.
List of workers who have been given the rights of permitting, responsible work manager, work foreman, supervisor
List of technical documentation
List of works performed in the order of routine operation
List of works performed according to orders and orders
List of means of intention transferred to the category of indicators
Electrical equipment logbook
Operational log
Journal of work accounting according to orders and orders
Assignment log! electrical safety groups for non-electrical personnel
Journal on means of measuring and accounting of electrical energy
Logbook for workplace briefings
Aggregate log
cable magazine
PNR schedules
Fire safety instructions
Instructions for labor protection at workplaces
Job and work instructions
Instructions for first aid in case of accidents
General plan showing buildings, structures and underground electrical communications
Work permit forms
Documents on maintaining restrictions for load regulation
Grounding device passport
Soil resistivity measurement protocol
Protocol for measuring the resistance of a grounding device
Touch voltage measurement protocol
Protocols for measuring short-circuit currents in electrical installations
Power supply diagrams
Emergency training schedule
Emergency training logbook
Schedule of visual inspections of part of the grounding device
The volume of operational documentation can be supplemented by the decision of the manager. The consumer or person responsible for electrical equipment.
Operational documentation should be periodically reviewed by higher operational or administrative and technical personnel and measures should be taken to eliminate any deficiencies found.
Operational documentation, diagrams of recording instrumentation, statements of readings of calculated electricity meters, output documents generated by the operational information complex of automated control systems are classified as strictly accounting documents and are subject to storage in the prescribed manner.
11. Electrical equipment repair technology
Maintenance.
Checking the reliability of fastening and tightening all fasteners of the electric machine, checking the serviceability of grounding, the uniformity of the air gap between the stator and the rotor, the proper operation of ventilation and cooling, the correct selection of fuse links;
Cleaning an electric machine from dust, oil and dirt without disassembling it;
Cleaning the slip rings or commutator;
Adjustment and fastening of traverses;
Restoration of insulation of jumpers and output ends;
Change or add, if necessary, lubricant to the bearings;
Checking the tight fit and condition of the coupling half on the shaft of the electric machine; measuring the insulation resistance of windings with a megohmmeter.
Average renovation.
All routine repair operations are carried out, and, in addition, the following is performed:
Complete disassembly of the electrical machine with the elimination of damaged windings without replacing it;
Washing of components and parts;
Replacement of faulty groove wedges and insulating bushings;
Washing, wiping and drying windings;
Impregnation of windings;
Coating of windings with enamels;
Checking the serviceability and fastening of the fan;
Grooving of shaft journals after surfacing and repair of squirrel cage;
Checking and adjusting gaps;
Changing flange gaskets;
If necessary, welding and sharpening of electric machine shields;
Grooving and grinding of slip rings;
Repair and adjustment of brush mechanisms;
Manifold grooving and processing;
Washing the sliding bearings and, if necessary, refilling the bearing shells or scraping them;
Partial soldering of the cockerels;
Testing winding insulation with increased voltage;
Balancing the rotor * (armature);
Electrical machine assembly and testing in accordance with GOST.
Major renovation.
All operations of current and medium repairs are carried out and in addition, the following is performed:
Complete or partial replacement of windings or their repair, followed by at least 2-fold impregnation;
Straightening, turning journals or replacing the rotor shaft;
Repair or production of shield and flange bearings;
Bulkhead slip rings or commutator;
Complete soldering of the cockerels;
Replacing the fan and fasteners;
Checking the fastening of the active iron on the shaft and in the stator and repairing it (if necessary);
Cleaning, assembly, painting of electrical machines and testing in accordance with GOST for new machines.
The purpose of the trolley workshop, its operating mode and working time funds. Justification of the method for organizing the repair of wagons, calculation of production process parameters and selection of the necessary technological equipment. Management in the trolley workshop.
course work, added 10/24/2012
Technological and technical characteristics of the main and auxiliary equipment of mill 350. Organization of work at the mill site. Metrological support for measuring dimensions of rolled products. Preparing cost estimates for rolled wheel profiles.
thesis, added 10/26/2012
Structure of the chief mechanic's service. Organization and technology of equipment maintenance and repair. Planning the work of the repair shop. Accounting for work and planning of technological equipment and its repair. Forms of remuneration for workers of working services.
practice report, added 12/24/2009
Description of equipment of OJSC "Minsk Construction Materials Plant". Organization of scheduled maintenance and repairs, procedure for carrying out, mechanization of disassembly, assembly and installation work. Structure and functioning of the mechanical repair shop.
practice report, added 01/23/2014
Characteristics of the enterprise and operating mode. Organization of production, as well as workshop activities according to the system of scheduled preventive maintenance. Calculation of the labor intensity of work and the required amount of equipment, the number of workers, and the wage fund.
course work, added 09/10/2015
Technological scheme for the production of rolled products. Calculation of hourly productivity and loading of the forming mill, annual pipe production volume. Calculation of roll weight. Selection of auxiliary equipment. Design and principle of operation of a sheet straightening machine.
course work, added 03/12/2015
Consideration of the problem of equipment reliability at JSC "Belarusian Metallurgical Plant". Purpose and principle of operation of the coil former in the section rolling shop. Drawing up a repair estimate sheet. Labor protection for mechanics. Ways to protect the atmosphere.
thesis, added 02/12/2015
Description of the technological production process in the crimping shop, the main technological lines of the shop. Calculation of unit parameters and selection of equipment for technological lines of a crimping mill, compilation of a metal balance, calculation of blooming parameters.
course work, added 06/07/2010
Operating mode of a mechanical workshop, operating time funds for equipment and workers. Technological processes and new technology. Determination of the number of sections and workshop turnover. Selection of lifting and transport vehicles. Calculation of the area of an industrial building.
course work, added 05/03/2015
Characteristics of the technical service of the service station "Krymdieselservice". Production structure, methods of vehicle maintenance and repair. Organization of the technological process of the engine department. Selection of equipment, calculation of site area.
Drawing machines are designed for the production of smaller diameter wire from wire rod (rough drawing) or from larger diameter wire.
Approximate drawing ranges:
Decide on the receiving device. The wire can be placed in baskets or wound on bobbins. It can be wound onto bobbins using either a simple single receiver or a double automatic receiver (for high-speed ones), which allows you to change bobbins without stopping the mill.
It should be remembered that the drawing process requires continuous lubrication using an emulsion. To do this, it is necessary to build an oil station, which includes pumps, an emulsion reservoir and, depending on the region, additional cooling devices, such as radiators or cooling towers.
The emulsion filtration system should not be neglected. This system is especially important in the case of further wire drawing, since copper microparticles that enter the die along with the emulsion at the time of drawing are pressed into the wire and become the point of rupture during the next stage of drawing.
In addition, the drawing line must be equipped with additional machines and equipment, such as a sharpening machine, a cold and/or hot welding machine. This also includes dies (dies), the set depends on what output diameter is needed. The main indicators of product quality (wire/core) are resistance and elongation factor.
If you plan to sell products after drawing, then you may need laboratory equipment to measure these indicators, and if the kit for measuring resistance is not expensive, then for measuring elongation this is expensive equipment, especially for large diameters.
If you plan to use the resulting products yourself, then you can get by with a simple tester for measuring resistance, and elongation can be measured by building a simple device for stretching the wire.
Rough drawing is an energy-intensive process, coupled with annealing, high-speed lines consume about 300 kW/h. As a rule, 2 operators work on such lines. Electricity consumption for average drawing is about 100 kW, for thin drawing about 50 kW.
DRAWING AND ROLLING MILL FOR THE PRODUCTION OF SELF-ANNEALD COPPER WIRE FROM ETP ROLD ROLL WITH A DIAMETER OF 8 mm
PREFACE
Production of copper wire from 8 mm ETP wire rod was started about 50 years ago using traditional rough drawing lines with an integrated electrical annealing system. During this time, rough drawing machines were improved both in the mechanical part and in the automation part. However, the basic design concept still requires that the wire is cooled during the process at each capstan before entering the die. To obtain soft wire, it must first be heated and then cooled.
Thus, the fundamental limitations of this process can be summarized as follows:
High energy consumption: about 80-90 kWh per ton of product is needed to recrystallize copper in the annealing device.Manual threading of wire into each die on each capstan, accompanied by the risk of injury
New process conceptis based on the use of rolling energy to increase the temperature of the wire during rolling, that is, it comes out at a temperature above the recrystallization temperature. Thus, it is possible to completely avoid the cost of heating the wire during annealing.
In addition, the energy required for rolling operations at this temperature is achieved with much less power consumption compared to a drawing machine. Copper Drawing Mill Systemis a revolutionary type of equipment. Below are the main benefits of this innovation process.
Main advantages
a ) No annealing required, so power consumption is lower
b ) Less expensive transformer
c ) No need for 5000 A cable
d ) The system is more environmentally friendly: savings of up to 50% compared to the traditional rough drawing operation (approx. 80 kWh/t)
When loaded for 250 days per year with a minimum system efficiency of 90% (in copper wire production Ø 2.0 mm) expected productivity is 14,500 tons per year. This corresponds to energy savings of 1,200,000 kWh per year. Taking into account the cost of electricity in Western European countries (including taxes and distribution costs) of approx. 0.1 Euro per kWh, total savings can be up to 120,000 Euro per year.
Annual Savings
= 2.7 t/hx24 hours/dayx250 days/yearx 0.9
x80 kWh/tx0.1 €/kWh ≈120,000 €/year
e ) No copper dust in the process
f ) Compact machine - only 5 m
g ) More space for subsequent operations
h ) Lower installation cost; all auxiliary systems included
i ) Feeding and reaching operating speed in less than 6 s; emergency stop deceleration in less than 3 seconds
1. PROJECT OVERVIEW
The mill is designed for processing copper wire rod with a diameter of 8 mm to soft wire with a diameter of 2 mm (elongation in the range of 25 - 35%), as will be further described below.
1.1 WIRE DIAMETER
The drawing and rolling mill is designed to process copper wire rod from Ø 8 mm to 2 mm.
Alternatively, this mill can be designed upon customer request to process copper wire rod from Ø 8 mm to 1.8 mm or 2.3 mm.
1.2 EXPECTED WIRE SPEED AND PRODUCTION VOLUME
The drawing and rolling mill is designed to operate in harsh conditions. The maximum electricity consumption of each cage will be 35 kWh.
The maximum mechanical speed at the output will be 30 m/s. Actual speed will be approx. 27 m/s for wire with a diameter of 2 mm.
Expected output for Ø 2 mm wire – approx. 2700 kg/h.
The direction of wire movement is from left to right (assuming the operator is facing the front of the line).
2. SYSTEM DESCRIPTION
The system is equipped with the following equipment:
2.1 RELEASE DEVICE FOR TWO LARGE COILS
The release device consists of the following components:
a ) Portal system
The gantry system is made of welded steel plates, where the copper wire rod is free to rise and rotate around a large cylinder before being fed into the drawing and rolling mill..
b ) Electromechanical safety equipment
Electromechanical safety equipment is placed directly in front of the top cylinder to provide emergency shutdown of the system if the wire rod becomes entangled during unwinding.
The take-off system allows for the placement of two large coils of copper wire for end butt welding operations.
Maximum unwinding speed: 1.75 m/s.
2.2 CORRECT DEVICE FOR THE ROLE ROLE
The unit is equipped with guide rollers and two sets of idle leveling wheels with manual adjustment for straightening the wire rod before entering the drawing and rolling mill.
2.3 DRAWING AND ROLLING MILL
In this specific configuration, the drawing and rolling mill is equipped with eight (8) rolling stands. The mill consists of the following components:
a ) Main bed
The bed is made of thick welded steel plates, fully annealed and sandblasted.
8 rolling stands are mounted on the front side. On the rear side there are gear reducers and one motoralternating currentat 300 kW with variable speed, production Siemens , driving 8 stands.
b ) Rolling stands
The rolling stands are located in the front part of the frame of the drawing and rolling mill. For ease of maintenance, each cage is made in the form of two “shells” (half-cases) containing the main shaft connected to the gearbox via a gear pair with a safety system in the form of a shear key. The main shaft carries one of the working rollers and two gears. All working roller profiles are made of steel or tungsten carbide and are quick-release.
Each cage is equipped with inlet and outlet guides. All components of the cage are replaceable, except for the working rollers and guides. An emulsion (soluble oil + water) is used to cool the guide wires and working rollers; the corresponding pumping system is switched on. Each stand is equipped with an emulsion shut-off valve and an emergency stop device in the event of a serious problem with the rollers. The cage bearings are lubricated with grease.
Setting the gap between the rollers, which require radial and axial adjustment of the auxiliary rollers, is carried out using an eccentric system. This operation is performed off-line using a special optical instrument (included in the delivery).
c ) Soundproof cover
A steel cover is supplied to cover the cages during operation. The cover is equipped with an exhaust flange (and a counterflange). The noise level under normal operating conditions is below 80 dB (when the operator is at a distance of 1 m from the doors).
d ) Special maintenance tool kit
Maintenance of the mill is very simple and can be performed by any trained operator. The scope of delivery includes the following special tools:
Optical device for stand adjustment
A set of special tools for assembling and disassembling rollers, bearings and shafts.
About the rolling sequence
The rolling sequence reflects the well known and testedthe principle when the wire rod is deformed in the form of a chain of geometric profiles: triangle/circle/triangle/circle; every second stand can produce round wire.
Below are the most characteristic features inoxidation millused in this system:
Diameter of wire rod at the entrance to stand 1
Maximum speed at the entrance to cage 1: 1.7 m/s
Wire diameter at the exit from stand 8: 2.0 mm (*)
Wire speed 2.0 mm diameter: 27 m/s
(*) Alternatively, the mill can be designed to produce either 1.8mm or 2.3mm wire.
2.4 TRANSIT JOINT
After leaving the last rolling stand, the wire enters a closed environment-controlled tank where a series of pulleys allow the wire to remain at the high recrystallization temperature for the required time.
2.5 WIRE COOLING SYSTEM
At the exit of the transit unit, the wire enters a high-speed cooling pipe, the function of which is to reduce the temperature of the wire to approx. 80÷90° C . At the outlet of the cooling zone, a drying unit is installed to remove the coolant/liquid. An emulsion is used as a refrigerant in the mill. All components are made of stainless steel.
2.6 COMPENSATOR
The compensator is located between the drawing and rolling mill and the coiler. It is designed to equalize speed differences during acceleration and deceleration, as well as to synchronize speed when working with associated equipment.
2.7 AUTOMATIC BURNER
Automatic coiling machine of a portal design with a vertical coiling capstan for the production of coils in accordance with the Buyer's dimensions.
The capstan has a hard metal coating.
Baskets arranged in a line:
Alone, empty, waiting
One in the process of filling
One, full, awaiting retrieval
One motorized chain conveyor drives the baskets when the central one is full.
When changing the basket, the wire is buffered into a storage tank below the coiling capstan. The wire is cut by hand. Synchronization of the coiler and the mill occurs through a compensator with wire. The maximum permissible wire speed is 30 m/s. The docker is equipped with a variable speed AC motor and control system. The dimensions of the bays are agreed upon with the buyer when ordering.
