Edit- a metalworking operation intended to eliminate distortions in the shape of a workpiece (dents, bulging, waviness, warping, curvature, etc.) through plastic deformation. The metal is straightened both in cold and heated states. Straightening can be done by hand on a steel or cast iron plate or on an anvil. Machine straightening is carried out on presses and straightening rollers.
For straightening the following are used: hammers made of soft materials (copper, lead, wood) with a round polished striker (a square striker leaves marks in the form of nicks); smoothers and supports (metal or wooden blocks) for straightening thin sheet and strip metal; correct headstocks for hardened parts with shaped surfaces.
The curvature of the workpieces is checked by eye using the gap between the plate and the workpiece laid on it. Bent areas are marked with chalk. The easiest way to straighten metal that is curved along a plane. In this case, strong blows are applied with a hammer or sledgehammer to the most convex places, reducing the force of the blow as they are straightened. In this case, the workpiece is periodically turned from one side to the other. It is more difficult to straighten metal that is bent along an edge. Here they resort to stretching part of the workpiece. It is recommended to straighten metal that has a twisted (spiral) bend using the unwinding method. To do this, one end of the workpiece is clamped with a bench vice, and the other with a hand vice. Then the curvature is straightened with a lever. The results of editing are checked by eye, and a more accurate check is carried out on a marking or control plate along the clearance.
Straightening (hardened workpieces is carried out with various hammers with a hardened striker or a special hammer with a rounded narrow side of the striker. The blows are applied not on the convex, but on the concave side of the workpiece. In this case, the metal fibers on the concave side are stretched and the workpiece is straightened. Straightening of workpieces complex shape, for example, a square whose angle between the measuring sides, are produced in the following ways: if the angle is less than 90°, then blows with a hammer are applied at the top internal corner, if more than 90°, - at the top of the outer corner.
Bending- one of the most common locksmith operations. It is used to give the workpiece a curved shape along a given contour. During the bending process, the metal is subjected to the simultaneous action of tensile and compressive stresses, so it is necessary to take into account the mechanical properties of the metal, its elasticity/degree of deformation, thickness, shape and cross-sectional dimensions of the workpiece, angles and bending radii of the part. The bending radius of the part should not be taken close to the minimum acceptable unless this is dictated by design requirements. It is advisable not to allow the bending radius to be less than the thickness of the workpiece, as this leads to the appearance of cracks and other defects. In a cold state, it is recommended to bend parts made of sheet steel with a thickness of up to 5 mm, of strip steel with a thickness of up to 7 mm, and of round steel with a diameter of up to 10 mm.
When bending a strip of sheet steel, a bend mark is first applied to it. Then the workpiece is clamped in a vice between the square jaws so that the marking line faces the stationary jaw of the vice and protrudes 0.5 mm above it. Finally, with hammer blows directed towards the stationary jaw, the end of the strip is bent
To bend the staple, the workpiece is clamped in a vice between a square and a mandrel bar and the first end is bent. Then, having placed a mandrel bar of the required size inside the bracket, the bracket is clamped in a vice at the level of the marks and the second leg is bent.
Chopping is a metal cutting operation. By using cutting tool- chisel, cross-cutter or groover - remove an excess layer of metal from the workpiece, cut it into pieces, cut out a hole, cut lubrication grooves, etc. Cutting is carried out in cases where, according to production conditions, machine processing is impossible or when it is not required high accuracy processing. Chopping of small workpieces is carried out in a vice, large workpieces are cut on a slab or anvil.
The following tools are used for chopping: chisel, crossmeisel, groovers.
A metalwork chisel consists of three parts: working 2, middle 3 and impact (striker) 4. The wedge-shaped cutting edge of chisel 1 and the striker are hardened and tempered. After heat treatment, the hardness of the cutting edge reaches HRC356...61, the striker - HRC337...41. The chisel has a length of 100...200 mm, and the width of the cutting edge is 5...25 mm, respectively. The sharpening angle of the chisel, depending on the material being processed, should be:
Hard materials(cast iron, hard steel, bronze) 70°
Medium hard materials (steel) .... 60°
Soft materials(copper, brass) 45°
Aluminum alloys and zinc 35°
The smaller the point angle, the less force must be applied to cut. However, the greater the hardness and brittleness of the metal being processed, the stronger the cutting edge should be and the larger the sharpening angle; The chisel head has the shape of a truncated cone with a semicircular upper base. Therefore, a blow delivered by a hammer always falls on its center.
The crossmeisel differs from the chisel in that it is narrower cutting edge. It is used for cutting out narrow grooves, grooves, etc. The sharpening angles, hardness of the working and impact parts of the cross-section are the same as those of a chisel.
Pointers differ from cross-cutters in the curved shape of the cutting edge and are used for cutting out lubrication grooves in bearing shells and bushings and for other similar work.
Before work, the chisel is placed on the workbench on the left side of the vice with the cutting edge facing you, and the hammer - with right side vice with the striker pointing towards the vice. Great importance when chopping, the mechanic's body has the correct position: at the vice you need to stand steadily, half-turn to them.
Welding defects
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Electrodes
Welding electrode is a metal or non-metallic rod made of electrically conductive material designed to supply current to the product being welded. Currently, more than two hundred are produced various brands electrodes, with more than half of the total product range being consumable electrodes for manual arc welding.
Welding electrodes divided into melting and non-melting. Non-consumable electrodes are made from refractory materials, such as tungsten in accordance with GOST 23949-80 "Tungsten welding non-consumable electrodes", synthetic graphite or electrical coal. Consumable electrodes are made from welding wire, which according to GOST 2246-70 is divided into carbon, alloy and high-alloy. A layer is applied on top of the metal rod by pressing under pressure. protective coating. The role of the coating is to metallurgically treat the weld pool and protect it from atmospheric exposure and ensuring a more stable arc burning.
Figure 8. Welding electrode
Blacksmithing
Types of jobs
Drawing or broaching
Drawing or broaching is an operation in which the workpiece, under the influence of impacts, is lengthened and reduced in cross section.
Draft
Upsetting is an operation in which the cross-sectional area of the workpiece is increased by reducing its height. During upsetting, the metal is stretched, which causes great stress in it. Before upsetting, the workpiece must be heated to high temperature over the entire cross-section and along the entire length. Precipitation is used in the following cases:
When it is necessary to mix up the fibers in the metal or give them a direction that would improve the quality of the product (for example, when forging gears);
When a workpiece of a given weight, but of insufficient cross-section, is forged;
When it is impossible to obtain a given quantity from the existing workpiece.
The middle of a short workpiece is also planted using rings. Before upsetting, the ends of the workpiece are pulled required size. Then one end of the workpiece is inserted into the lower ring mounted on the firing pin, and the upper ring is put on the other end. The hammer strikes the workpiece and the upper ring, and the middle part of the workpiece is upset. To plant the middle part, it is necessary that the walls internal hole in one ring had a slope of 6-7%, otherwise it would be very difficult to free the forging from the rings.
Tackle
Using the same crimps, you can roll the end of the pipe. To do this, the heated end of the pipe is placed on the lower crimp, and by hitting the upper crimp with a sledgehammer, turning the pipe at the same time, reduce its diameter.
Stamps
IN Lately Free forging under hammers and backing dies is becoming more and more widespread. The use of backing dies does not require large expenditures, and therefore their production is economically justified when forging even small batches of parts. The main advantage of backing dies is that the flow of metal in them is limited by the walls of the die and the resulting forgings are close in accuracy to stamped ones. This makes it possible to sharply reduce the allowance for machining, which reduces metal consumption and the overall labor intensity of manufacturing the part. In addition, the working conditions of the blacksmith are facilitated, and labor productivity increases by 5-6 times.
Bend
Bending is an operation in which part of the workpiece is bent at a given angle to another part of the workpiece. The bend is made on an anvil, from which the bent part is hung so that the top of the bend angle is aligned with the edge of the anvil. Strikes with a sledgehammer are applied to the hanging part, holding the workpiece on the anvil with pliers and a handbrake, and the large workpiece with pliers and another sledgehammer held by an auxiliary worker. The bending angle is checked using the template. At the point of bending, the material stretches and becomes thinner. If it is required that the thickness of the material at the bending point does not decrease, the workpiece at the bending point is set to the required thickness. Thin strips of steel can be bent in a vice. It is often necessary to bend the workpiece or part being forged under different angles. When forging under a hammer, the workpiece is clamped between the hammer strikers and, hitting the free end of the workpiece with a sledgehammer, it is bent. In this case, the outer layers of the metal are stretched and the inner layers are compressed. Before bending, local heating is performed, i.e., only the place where the workpiece will be bent is heated. In free forging, whenever possible, bending should be done using backing dies. Bending in backing dies requires much less time, and the dimensions of the forging are more accurate.
Firmware
Sewing holes in round or rectangular section made with punches of the same shape. A pad with a hole of the appropriate size and profile is placed on the anvil, and the material to be processed is placed on it. The hole is drilled by hitting a punch with a sledgehammer. Holes in thick blanks are punched under hammers, and this process occurs differently than with hand forged. Instead of a punch, piercing is used.
Chopping off material
The material is cut off using a blacksmith's chisel according to the markings. Forge welding is the operation of joining two ends of steel heated to white heat. Blacksmith axes are used to cut metal under hammers. Metal under hammers is usually cut hot. Metal cutting is carried out at a temperature not lower than 700°. Blanks are cut using hammers in various ways.
Scale
Strong welding is hampered by the film of scale formed during heating. In order for the scale to easily come off, the heated ends are sprinkled with fine, clean quartz sand before welding and struck against an anvil.
Chisels are hardened as follows. The working part of the chisel is heated to a temperature of 780-830° (light cherry heat). Then, holding the chisel by the head with pliers, soak the heated part in water, lowering it in a vertical position.
Flexible (bending) is an operation, as a result of which the workpiece takes the required shape (configuration) and dimensions due to stretching of the outer layers of metal and compression of the inner ones. During bending, all the outer layers of the material are stretched, increasing in size, and the inner layers are compressed, correspondingly decreasing in size. And only the metal layers located along the axis of the bent workpiece retain their original dimensions after bending. When bending, it is important to determine the dimensions of the workpieces. In this case, all calculations are carried out relative to the neutral line, i.e. those layers of the workpiece material that do not change in size during bending. If the drawing of a part that must be made flexible does not indicate the size of the workpieces, the mechanic must independently determine this size. The calculation is made by calculating the size of the part along the center line (determine the length of straight sections, calculate the length of curved sections and summarize the data obtained).
Bending can be done manually, using various bending devices and using special bending machines.
Tools, devices and materials used
when bending
As tools for bending sheet material with a thickness of 0.5 mm, strip and rod material with a thickness of up to 6.0 mm, steel hammers with square and round strikers weighing from 500 to 1000 g, hammers with soft inserts, wooden hammers, pliers and round nose pliers. The choice of tool depends on the material of the workpiece, the dimensions of its cross-section and the design of the part that should be obtained as a result of bending.
Bending with a hammer is carried out in a metalworker's plane-parallel vice using mandrels (Fig. 2.44), the shape of which must correspond to the shape of the part being bent, taking into account the deformation of the metal.
Hammers with soft inserts (see Fig. 2.33) and wooden hammers - mallets are used for bending thin-sheet material up to 0.5 mm thick, non-ferrous metal blanks and pre-processed blanks. Bending is done in a vice using mandrels and linings (on the jaws of the vice) made of soft material.
Pliers and round nose pliers are used when bending profiles with a thickness of less than 0.5 mm and wire. Pliers (Fig. 2.45) are designed to grip and hold workpieces during the bending process. They have a slot near the hinge. The presence of a slot allows you to bite off the wire. Round nose pliers (Fig. 2.46) also provide gripping and holding of the workpiece during the bending process and, in addition, allow wire bending.
Manual bending in a vice is a complex and labor-intensive operation, therefore, to reduce labor costs and improve the quality of manual bending, various devices are used. These devices are usually designed to perform a narrow range of operations and are manufactured specifically for them.
In Fig. Figure 2.47 shows a device for bending a hacksaw square. Before bending, the roller 2 of the bending device is lubricated machine oil. Lever 1 with bending roller 2 is moved to the upper position A. The workpiece is inserted into the hole formed between roller 2 and mandrel 4. Lever 1 is moved to the lower position B, giving the workpiece 3 the desired shape.
Other bending devices work in a similar way, for example, a device for bending a ring from a rod round section(Fig. 2.48).
The most difficult operation is pipe bending. The need for pipe bending arises during assembly and repair operations. Pipe bending is carried out both cold and hot. To prevent the occurrence of deformations of the internal lumen of the pipe in the form of folds and flattening of the walls, bending is carried out using special fillers. These features determine the use of some specific tools, devices and materials when bending pipes.
Devices for heating pipes. Hot pipe bending is performed after preheating with currents. high frequency(HDTV), in fiery furnaces or furnaces, gas-acetylene burners or blowtorches directly at the bending site. The most rational heating method is HDTV heating, in which heating is carried out in a ring inductor under the influence of magnetic field created by high frequency currents.
Fillers when bending pipes are selected depending on the material of the pipe, its size and bending method. The following are used as fillers:
Sand - when bending pipes with a diameter of 10 mm or more made of annealed steel with a bending radius of more than 200 mm, if it is carried out in both cold and hot states; pipes with a diameter of over 10 mm from annealed copper and brass with a bending radius of up to 100 mm in a hot state;
Rosin - for cold bending of annealed copper and brass pipes with a bending radius of up to 100 mm.
The use of filler when bending pipes is not required if they are made of annealed steel, have a diameter of up to 10 mm and a bending radius of more than 50 mm. In this case, bending is done in a cold state. Also, pipes made of brass and copper with a diameter of up to 10 mm with a bending radius of over 100 mm are cold bent without filler. Without filler, pipes are bent in special devices, where backpressure, which prevents the occurrence of deformations in the internal lumen of the pipe, is created by other means.
The simplest device for bending pipes is a plate, fixed on a workbench or in a vice, with holes in which pins are installed (see Fig. 2.47). The pins act as stops needed when bending pipes. Roller devices of various designs are also used.
Plumbing: Practical guide for mechanic Kostenko Evgeniy Maksimovich
2.7. Manual and mechanical straightening and metal bending
For straightening shaped, sheet and strip metal, various types of hammers, plates, anvils, rolls (for straightening tin), manual screw presses, hydraulic presses, roller devices and gates.
Bending of metal depending on its thickness, configuration or diameter is done with a hammer using metal tongs or blacksmith's tongs on a straightening plate, in a vice or in molds or on an anvil. You can also bend metal in various bending fixtures, bending machines, press brake dies, and other equipment.
The hammer is percussion instrument, consisting of a metal head, handle and wedge fig. eleven).
Rice. 11. Plumber's hammer:
a – metal head; b – handle; c – wedge
The hammer is widely used in performing different operations plumbing; This is one of the main tools when performing locksmith work.
The metal part consists of the following elements: a wedge-shaped part, a slightly rounded butt (impact part) and a hole. The hammer handle is made of hard wood with a cross-section and length depending on the size of the hole in the hammer and its weight. After placing the hammer on the handle, a wooden or metal wedge is driven into it to protect the hammer from falling off the handle.
Hammers come with a round and square head. Bench hammers are made from tool carbon steel U7 or U8 (Table 1). The working part of the hammers is hardened to hardness H.R.C. 49–56.
Table 1
Weight and dimensions of locksmith hammers
Editing is the operation of returning something crooked or bent. metal products original rectilinear or other shape. Straightening is done hot or cold manually, as well as using devices or machines.
Most often, wire, hot-rolled or cold-drawn rods, strip and sheet metal are straightened. Sectional metal (angles, channels, T-beams, I-beams and rails) undergoes editing less frequently.
A material or product made of non-ferrous metals should be adjusted taking into account its physical and mechanical properties with a hammer made of the appropriate metal. Hammers made of the following non-ferrous metals are used: copper, lead, aluminum or brass, as well as wooden and rubber hammers.
Flexible called the operation of giving metal a certain configuration without changing its cross-section and processing the metal by cutting. Bending is done cold or hot manually or using devices and machines. Bending can be done in a vice or on an anvil. Bending metal and giving it a certain shape can facilitate the use of templates, core molds, bending dies and fixtures. Bending large quantity processing of metal rods to give them a certain shape is possible only in dies and bending equipment specially designed and manufactured for this purpose.
Rice. 12. Pipe bending device
The wire bends under a certain radius or around the circumference with round teeth, and when bending under small angle– pliers;
For complex bending, circle pliers and pliers can be used simultaneously. In some cases, a vice is used when bending wire.
Pipe bending can be done hot or cold using special templates or rollers using bending devices (Fig. 12) or pipe bending machines.
Thick-walled pipes with a diameter of no more than 25 mm and a bending radius of more than 30 mm can be bent in a cold state without filling them with dry fine sand, lead, rosin and without inserting a coil spring into them. Pipes of large diameters (depending on the wall thickness and the grade of metal from which the pipe is made) are bent, as a rule, by heating the bending point and filling the pipe with the appropriate material. In this case, the ends of the pipe are plugged with plugs, which reduces the possibility of its breakage or flattening during bending. Pipes with a seam should be bent in such a position that the bending force is applied in a plane perpendicular to the seam.
Pipe flaring- this is a diametric expansion of the pipe ends outward in order to obtain a tight and durable press connection of the pipe ends with the holes into which they are inserted. It is used in the manufacture of boilers, tanks, etc. Flaring is performed mainly with manual flaring roller tools or conical mandrels.
Spring- this is a part that, under the influence of external forces, elastically deforms, and after the cessation of the action of these forces returns to its original state. Springs are used in various machines, devices, machines and equipment. Springs are classified according to their shape, operating conditions, type of load, type of tension, etc. Based on their shape, springs are divided into flat, helical (cylindrical, shaped, telescopic) and conical. Based on the type of loading, they are divided into tension, torsion and compression springs. Springs are made with right or left winding, spiral disc, bent, flat, figured and ring (Fig. 13).
The spring must support parts or assembly units of machines in a certain position, eliminate or calm vibrations, and also perceive the energy of a part or machine assembly in motion, make it possible to elastically suspend machine parts or counteract a certain force. The spring also serves as an indicator of a certain force.
Rice. 13. Springs: a – flat; b – cylindrical screw; c – spiral; g – disc-shaped; d – bent; e – ring
Springs are made of spring or spring steel. It can be high-carbon steel or alloyed spring and spring steel with the addition of manganese, chromium, tungsten, vanadium, and silicon. Chemical composition spring and spring steel, heat treatment conditions, as well as mechanical properties are determined by the relevant GOST and technical specifications.
Rice. 14. Winding a coil spring in a vice manually
Springs are made by hand or by machine. One of the simplest manual methods is the production of springs in a vice (Fig. 14) using a round rod with a handle with a diameter slightly smaller than the internal diameter of the spring, and special wooden cheeks inserted between the jaws of the vice cheeks. Helical springs can also be wound on drilling, lathe or special winding machines.
The length of round wire required to wind a helical spring is determined by the formula:
L = ?D cp n,
Where L– total length of the wire;
D cp – average diameter of spring coils (equal to internal diameter plus wire diameter); n– number of turns.
Rubber spring coupling- This is a type of spring. Rubber connecting spring parts are used in various machines, mechanisms and equipment for connecting shafts and a number of other parts operating in conditions dynamic loads. They have the ability to receive and store energy, dampen vibrations and are used as flexible and elastic couplings.
Before installing a spring or a rubber connecting spring part, you should first check that the type, characteristics and quality of the spring correspond to the drawing and technical requirements for assembling a machine or mechanism. A spring or rubber connecting spring part that does not meet these requirements or has mechanical damage will not ensure the operability of the machine or mechanism.
When straightening and bending metal, it is necessary to check technical condition tools used, correctly and accurately fix the material on a plate, in a vice or other device. The sleeves of clothing should be buttoned at the wrists, and mittens should be worn on the hands.
From the book Instructions: how to make a bow with your own hands author Tramp Sergey From book Home master author Onishchenko Vladimir From the book Artistic Metal Processing. Enameling and artistic blackening author Melnikov Ilya From the book Ceramic Products author Doroshenko Tatyana Nikolaevna From book Welding work. Practical guide author Kashin Sergey Pavlovich From book Engraving works[Techniques, techniques, products] author Podolsky Yuri Fedorovich From the book Locksmithing: A Practical Guide for a Locksmith author Kostenko Evgeniy Maksimovich From the book Garage. We build with our own hands author Nikitko Ivan From the author's book2.8. Manual and mechanical cutting and sawing Cutting is the operation of dividing a material (object) into two separate parts using hand scissors, a chisel or special mechanical scissors. Sawing is the operation of separating a material (object) with
From the author's book5.1. Manual Hot Forging Manual hot forging is the process of working metal heated to a temperature above the recrystallization limit (for steel - between 750 and 1350 °C) to give it a specific shape using a hand hammer or mallet.
From the author's book5.2. Mechanical hot processing Mechanical hot processing is the processing of metal heated to a temperature above the recrystallization temperature (for steel - in the range from 750 to 1350 °C), which makes it possible to obtain products of the required shape using special machines and
Editing is an operation to eliminate defects in workpieces and parts in the form of concavity, convexity, waviness, warping, curvature, etc. Its essence lies in the compression of the convex layer of metal and the expansion of the concave one.
The metal is straightened both in cold and heated states. The choice of one or another straightening method depends on the amount of deflection, size and material of the workpiece (part).
Straightening can be done manually (on a steel or cast iron leveling plate) or machine (on leveling rollers or presses).
Correct plate, just like the marking one, must be massive. Its dimensions can be from 400X400 mm to 1500X X3000 mm. Plates are installed on metal or wooden coasters, ensuring the stability of the slab and its horizontal position.
To straighten hardened parts (straightening), straightening heads are used. They are made of steel and hardened. The working surface of the headstock can be cylindrical or spherical with a radius of 150-200 mm.
Manual straightening is carried out with special hammers with a round, radius or insertable soft metal striker. Thin sheet metal is straightened with a mallet (wooden hammer).
When straightening metal, it is very important to choose the right places to strike. The force of the impact must be commensurate with the amount of curvature of the metal and reduced as it moves from the greatest deflection to the least.
When the strip is bent strongly, blows are applied to the edge with the toe of a hammer to one-sidedly stretch (lengthen) the bending points.
Strips with a twisted bend are straightened using the unwinding method. They check the editing “by eye”, and if there are high requirements for the straightness of the strip - straight edge or on a test plate.
Round metal can be straightened on a slab or on an anvil. If the rod has several bends, then the extreme ones are straightened first, and then those located in the middle.
The most difficult part is editing sheet metal. The sheet is placed on the slab with the protrusion facing up. The blows are applied with a hammer from the edge of the sheet towards the convexity. Under the influence of impacts, the flat part of the sheet will be stretched, and the convex part will straighten.
When straightening hardened sheet metal, apply gentle but frequent blows with the toe of a hammer in the direction from the concavity to its edges. The upper layers of metal are stretched and the part is straightened.
Shafts and round workpieces of large cross-section are straightened using a manual screw or hydraulic press.
In terms of working methods and the nature of the work process, another metalworking operation - bending metals - is very close to straightening metals. Metal bending is used to give the workpiece a curved shape according to the drawing. Its essence lies in the fact that one part of the workpiece is bent relative to the other at a given angle. Bending stresses must exceed the elastic limit, and the deformation of the workpiece must be plastic. Only in this case will the workpiece retain its given shape after the load is removed.
Manual bending produced in a vice using a plumber's hammer and various devices. The sequence of bending depends on the size of the contour and the material of the workpiece.
Bending of thin sheet metal is done with a mallet. When using various mandrels for bending metals, their shape must correspond to the shape of the part profile, taking into account the deformation of the metal.
When bending a workpiece, it is important to correctly determine its dimensions. The length of the workpiece is calculated according to the drawing, taking into account the radii of all bends. For parts bent at right angles without rounding with inside, the bending allowance of the workpiece should be from 0.6 to 0.8 of the metal thickness.
When plastic deformation of metal occurs during bending, the elasticity of the material must be taken into account: after the load is removed, the bending angle increases slightly.
The manufacture of parts with very small bending radii is associated with the danger of rupture of the outer layer of the workpiece at the bending point. The size of the minimum permissible bending radius depends on the mechanical properties of the workpiece material, the bending technology and the quality of the workpiece surface (see Table 6 of Appendix 2). Parts with small radii of curvature must be made of plastic materials or pre-annealed.
When manufacturing products, sometimes it becomes necessary to obtain curved sections of pipes bent to different angles. Solid-drawn and welded pipes, as well as pipes made of non-ferrous metals and alloys, can be bent.
Pipe bending is done with or without filler (usually dry river sand). This depends on the pipe material, its diameter and bending radius. The filler protects the pipe walls from the formation of folds and wrinkles (corrugations) in places of bending.
Metal straightening is an operation to remove defects on workpieces and parts in the form of convexity, concavity, warping, waviness, curvature, etc. The meaning of the edit metal consists of expansion of the concave part of the metal and compression of the convex surface of the metal.
The metal is subjected to straightening, both in a heated state and in a cold state. The choice of one or another type of editing depends on the size of the cuts, deflection and material of the part.
Metalworking using this method can be either manual (on a cast iron or steel plate) or machine (on presses or rollers). The correct slab should be massive. Its dimensions should be from 400x400 mm. or up to 1500X1500 mm. The slabs are installed on wooden or metal stands, which provide good stability and horizontal position.
For editing processing For hardened parts (straightening), straightening headstocks are used. They are made of steel and are hardened before use. Herself working surface the headstock can be spherical or cylindrical with a radius of 100-200 mm. (see photo)
Manual straightening of metal made with special hammers with an inserted, radius, round striker made of soft metal. Thin sheet metal is most often straightened with a mallet. When straightening metal, it is very important to choose the right place where to strike, and the force of the strike must be measured against the amount of curvature and changed as it moves to the best state.
Types of metals that have a twisted bend are processed using the unwinding method. Metals round shape can be edited on an anvil or slab. If the twist has several bends, then straightening should begin from the edges, and then process the bends in the middle.
The most difficult thing in this type is sheet metal straightening. This type of metal must be placed on the slab with the curve or convex side up. The blows must be applied towards the convexity (bend) from the edges of the sheet. Under the influence of impacts, the convex part of the sheet will straighten, and the flat part will be stretched.
When straightening hardened sheet metal, not strong but frequent blows are applied with a hammer, directed from the concavity to the edges. The part is straightened and the upper parts of the metal are stretched.
Large cross-section round and shaft workpieces are processed using a hydraulic or screw process.
By nature and methods of work metal straightening very easy to compare with another type of metal processing - this is a process metal bending. Metal bending is used to give the workpiece a shape according to the drawing. Its meaning is that one of the parts of the workpiece is bent towards the other at a certain angle. The deformation of the part must be plastic, and the bending stress must have a lower characteristic compared to the elastic limit, because if you use further changes in the structure of the part, for example, it will be difficult. In this case, the workpiece will retain its shape after the end of the loading process. Manual bending done in a vice, using a hammer and other devices. Execution Sequence metal bending depends on the material and the contour of the workpiece.
Sheet metal bending made with a mallet. When using various mandrels for metals, the shape of the mandrels must correspond to the shape of the part, taking into account the deformation of the metal.
When bending a workpiece, you need to set its dimensions correctly. The length of the workpiece is determined according to the drawing, taking into account all the bends on the workpiece. For parts that bend without rounding from the inside and at right angles, the bending allowance of the part should be from 0.5 to 0.8 mm of metal thickness.
During plastic deformation of a part during the bending process, the elasticity of the materials must be taken into account: the bending angle increases slightly after the load is removed. After the load is removed, the part can be processed different ways one of them
Manufacturing and metalworking of parts with a very small bend radius can lead to rupture of the outer layer of the workpiece. The size of the minimum bending radius on metal completely depends on the properties of the metal, the quality of the workpieces and their bending technology. Parts with a small bending radius must be made from plastic materials.
Sometimes during the manufacture of products there is a need to obtain curved pipes bent at ordinary angles. Bending Can be produced on welded and seamlessly drawn pipes, as well as pipes made of alloys and non-ferrous metals.
Pipe bending made with filler (most often river sand), the process is possible without it. In this case, it depends on the diameter, its bending radius, and the material of the pipe. Filler, i.e. sand prevents the walls of the pipe from forming wrinkles and bending folds. By cutting metal pipes, they are given the required form and sizes.
