Purpose and application of metal dressing. Essence, purpose and methods of straightening metal; tools, fixtures and materials used in straightening; basic rules for performing work when editing. Tool for straightening metal. screw yoke
Metal dressing
To Category:
Metal bending and straightening
Metal dressing
The curvature of the parts is checked by eye or by the gap between the plate and the part laid on it. The edges of the curved places are marked with chalk.
When editing, it is important to choose the right places to hit. The force of impacts should be commensurate with the amount of curvature and gradually decrease as you move from the greatest bend to the smallest. Editing is considered complete when all irregularities disappear and the part becomes straight, which can be determined by applying a ruler. Editing is carried out on an anvil, a regular plate or reliable linings that exclude the possibility of parts slipping from them upon impact.
To prevent hands from shocks, vibrations when straightening metal, it is necessary to wear gloves, firmly hold the parts, workpieces on the plate or anvil.
Edit strip metal carried out in the following order. On the convex side, the boundaries of the bends are marked with chalk, after which on left hand put on a mitten and take a strip, and in right hand take a hammer and assume a working position.
The strip is placed on a regular slab so that it lies flat on the slab with a convex upwards, touching at two points. Impacts are applied to the convex parts, adjusting the impact force depending on the thickness of the strip and the magnitude of the curvature; the greater the curvature and the thicker the strip, the stronger the blows. As the strip is straightened, the impact force is weakened and more often the strip is turned over from one side to the other until it is completely straightened. With several bulges, first straighten those closest to the ends, and then located in the middle.
The results of editing (straightness of the workpiece) are checked by eye, and more precisely, on a marking plate along the clearance or by applying a ruler to the strip.
Editing a bar. After checking by eye on the convex side, the boundaries of the bends are marked with chalk. Then a bar is placed on a slab or anvil (Fig. 1) so that the curved part is convex upwards. Hammer blows are applied on the convex part from the edges of the bend to the middle part, adjusting the impact force depending on the diameter of the rod and the size of the bend. As the bend is straightened, the impact force is reduced, finishing with light blows and turning the bar around its axis. If the bar has several bends, first those closest to the ends are corrected, then those located in the middle.
Rice. 1. Editing of round metal
Rice. 2. Editing scheme sheet material: a, b - bent blanks, c. d - distribution of shocks
Edit sheet metal more complex than previous operations. Sheet material and blanks cut from it may have a wavy or bulged surface. On workpieces with waviness along the edges (Fig. 2, a), the wavy areas are first outlined with chalk or a soft graphite pencil. After that, the workpiece is placed on the plate so that the edges of the workpiece do not hang down, but lie completely on the supporting surface, and pressing it with a hand, they start straightening. To stretch the middle of the workpiece, hammer blows are applied from the middle of the workpiece to the edge as indicated in Fig. 2, in circles. Circles of smaller diameters correspond to smaller strokes, and vice versa.
Stronger blows are applied in the middle and the force of the blow decreases as it approaches its edge. In order to avoid the formation of cracks and work hardening of the material, it is impossible to apply repeated blows to the same place of the workpiece.
Particular care, attention and caution are observed when straightening blanks from thin sheet material. They apply light blows, since with an incorrect blow, the side faces of the hammer can either pierce the sheet blank or cause the metal to be drawn out.
Rice. 3. Editing thin sheets: a - with a wooden hammer (mallet), b - with a wooden or metal bar
When straightening blanks with bulges, warped areas are revealed, and it is established where the metal is more bulged (Fig. 2). The convex sections are outlined with chalk or a soft graphite pencil, then the workpiece is placed on the plate with the convex sections up so that its edges do not hang, but lie completely on the supporting surface of the plate. Editing begins from the edge closest to the bulge, along which one row of hammer blows is applied within the limits indicated on the surface covered with circles (Fig. 2, d). Then they strike on the second edge. After that, a second row of blows is applied along the first edge and again they go to the second edge, and so on until they gradually approach the bulge. Hammer blows are applied often, but not strongly, especially before the end of the edit. After each impact, its impact on the workpiece at the site of impact and around it is taken into account. Do not allow multiple blows to the same place, as this may lead to the formation of a new convex area.
Under the blows of the hammer, the material around the convex place is pulled out and gradually leveled off. If there are several bulges on the surface of the workpiece at a small distance from each other, with hammer blows at the edges of individual bulges, these bulges are forced to connect into one, which is then ruled by blows around its boundaries, as indicated above.
Thin sheets rule light wooden hammers (mallets - Fig. 3, a), copper, brass or lead hammers, and very thin sheets are placed on a flat plate and smoothed with metal or wooden blocks(Fig. 3b).
Straightening (straightening) of hardened parts. After hardening, steel parts sometimes warp. The straightening of parts that are bent after hardening is called straightening. The straightening accuracy can be 0.01-0.05 mm.
Depending on the nature of the straightening, hammers with a hardened striker or special straightening hammers with a rounded face are used.
Rice. 4. Straightening of hardened parts: a - on the straightening headstock, b - square along the inner corner, c - along the outer corner, d - places of impact
lazy side of the striker. In this case, it is better to place the part not on flat plate, but on the straightening headstock (Fig. 4, a). Impacts are applied not on the convex, but on the concave side of the part.
Products with a thickness of at least 5 mm, if they are not hardened through, but only to a depth of 1-2 mm, have a viscous core, so they are straightened relatively easily; they need to be straightened as raw parts, i.e., strike at convex places.
Editing a hardened square, in which, after hardening, the angle between the shelves has changed, is shown in fig. 4, 6-g. If the angle has become less than 90 °, then hammer blows are applied at the top inner corner(Fig. 84 b and d, left), if the angle has become more than 90 °, blows are applied at the top of the outer corner (Fig. 4, c and d, right).
In the case of warpage of the product along the plane and along a narrow rib, straightening is performed separately - first along the plane, and then along the rib.
Editing of short bar material is carried out on prisms (Fig. 5, a), regular plates (Fig. 5, b) or simple linings, striking with a hammer on convex places and curvatures. Having eliminated the bulges, straightness is achieved by applying light blows along the entire length of the bar and turning it with the left hand. Straightness is checked by eye or by the gap between the plate and the bar.
Rice. 5. Editing of short shafts and bars: a - on prisms, b - on a plate
Strongly springy and also very thick workpieces are dressed on two prisms, striking through a soft pad to avoid nicks in the workpiece. If the forces developed by the hammer are insufficient for straightening, manual or mechanical presses are used.
Editing (straightening) is an operation by which irregularities, curvature or other imperfections in the shape of workpieces are eliminated. Editing and straightening have the same purpose, but differ in the methods of execution and the tools and devices used.
Editing is the straightening of metal by the action of pressure on one or another part of it, regardless of whether this pressure is produced by a press or by hammer blows. „
Dressing is, as a rule, a preparatory operation that precedes the main operations of metal processing.
Editing is subjected to steel sheets and sheets of non-ferrous metals and their alloys, strip, bar material, pipes, wire, as well as metal welded structures. Workpieces and parts made of fragile materials (cast iron, bronze, etc.) cannot be edited.
There are two methods of dressing metals: manual dressing, performed with a hammer on steel cast-iron straightening plates, anvils, etc., and machine straightening, performed on straightening machines. At manual editing the locksmith looks for places on the surface of the workpiece or part, upon impact on which the workpiece would straighten out, that is, it would lie on the plate, without bulges, bends or waviness.
The metal is straightened both cold and hot. In the latter case, it must be borne in mind that the straightening of steel billets and parts can be carried out in the temperature range of 1100-850 °C. Heating above the specified temperatures leads to overheating, and then to burnout of the workpieces, i.e., to an irreparable marriage.
Editing is used in cases where it is necessary to eliminate the distortion of the shape of the workpiece - waviness, warping, dents, curvature, bulging, etc. The metal can be edited both in cold and heated form. Heated metal is easier to edit, however, this is also true for other types of its plastic deformation, for example, bending.
At home, dressing should be done on an anvil or a massive plate of steel or cast iron. The working surface of the stove must be flat and clean. In order to make the impact noise less loud, the stove should be installed on wooden table, with which, in addition, it is possible to level the plate so that it is in a horizontal position.
For editing, you need a special locksmith tool. You can’t produce it with any hammer that is at hand, the metal can not only not straighten out, but get even bigger defects. The hammer must be made of soft material- lead, copper, wood or rubber. In addition, it is impossible to edit metal with hammers with a square striker - it will leave traces in the form of nicks on the metal surface. The hammer head should be round and polished.
In addition to hammers, wooden and metal trowels and supports are used. They are used for straightening thin sheet and strip metal. For dressing hardened parts with shaped surfaces, there are correct headstocks.
It’s probably not worth reminding that metal straightening (straightening) must be done in work gloves, regardless of whether hard work or not, whether the workpiece is large or small, and whether it is severely warped.
To check the curvature of the workpiece, you need to lay it on smooth plate that surface, which after editing should be a plane. The gap between the plate and the workpiece will indicate the degree of curvature that needs to be eliminated. Curved places must be marked with chalk, so it is much easier to strike with a hammer than focusing only on the curvature noticeable to the eye.
Straightening of strip metal bent in a plane is the simplest operation. The curved workpiece must be positioned so that it has two points of contact with the anvil. Hits with a hammer or sledgehammer should be applied to the most convex places and reduce the force of blows as the bulges become smaller. Do not strike only on one side of the workpiece, the metal may bend into reverse side. To prevent this from happening, the workpiece must be turned over from time to time. For the same reason, you should not strike several blows in a row in the same place.
If there are several bulges, you must first straighten the edges of the workpiece, and then its middle.
Edit round metal- this type of work is basically similar to straightening strip metal - you need to mark uneven places with chalk and place the workpiece with the bulge up, blows should be applied to the bulge from the edges of the bend to the middle of the bulge. When the main curvature is corrected, the force of impacts must be reduced and the metal rod periodically rotated around its axis in order to prevent curvature in the opposite direction.
metal rods square section must be done in the same order.
Editing of metal twisted in a spiral is carried out by the method of unwinding. In order to straighten the curvature, you need to clamp one end of the twisted metal into a large vice on locksmith's table, the other - in manual vices. Having untwisted the metal to the extent that can be controlled by eye, you need to continue editing on a smooth, verified plate conventional method, controlling the curvature through the light.
DURING THE CLASSES
Plan
1. Editing of metal.
2. Tools and fixtures used in straightening metal.
3. Basic rules for performing work when straightening metal.
4. Typical Defects when editing metal, the causes of their occurrence and ways to prevent them.
5. Safety rules for metal straightening.
We must learn to do everything so well
as soon as we can, and identify our mistakes.
Karl Raymond Popper
Hello dear students!
Before proceeding directly to the subject of our consideration, this is an acquaintance with the technology of straightening metal, let me tell you a little about the organization of labor, about
how to equip workplace which tools to choose and which ones to use
materials. So, let's begin….
Workplace equipment is far from the last thing, although many often do not
do not pay attention to this point. It doesn't matter what you have available, be it
small box with tools or a whole workshop - order should be everywhere. And
how quickly you find the tool you need depends on the speed of execution
one job or another. And besides, it is much more pleasant when everything is in its place and
always at hand.
Rolled metal products, pipes and sheet steel due to incorrect transport practices
and storage are warped, bent. To eliminate these defects,
Edit- This is an operation to straighten a bent or warped metal, which can only be subjected to ductile materials: aluminum, steel, copper, brass, titanium.
There are two types of metal straightening: cold straightening and hot straightening. Editing is carried out
On special right plates, which are made of cast iron or steel.
edit small parts can be crafted on blacksmith anvils. Edit
metal is carried out with hammers of various types depending on the condition
surface and material of the part being dressed.
When dressing workpieces with a raw surface, hammers are used with
round strikers weighing 400g. A round head leaves fewer marks on the surface than a square one.
When dressing workpieces with a treated surface, hammers are used that have strikers with soft inserts (made of copper, aluminum), which do not leave marks on the surface. When editing sheet material, wooden mallets are used, and very thin sheets are ruled with wooden or metal bars - trowels.
Editing is carried out in several ways: bending, stretching and smoothing.
Editing by bending used for straightening round (rods) and shaped material, which
have a fairly large cross section. In this case, hammers with steel heads are used. The workpiece is placed on the correct plate with the bend upwards and blows are applied to the convex places, bending the workpiece in the direction opposite to the existing bend. As the workpiece is straightened, the impact force is reduced.
Pull edit used when straightening sheet material having bulges
or waviness. Such editing is carried out with hammers with soft metal strikers or mallets. In this case, the workpiece is placed on a regular plate with the bulges up and frequent light blows are applied, starting from the border of the bulge, towards the edge of the workpiece. The strength of the blows gradually decreases. In this case, the metal is stretched to the edges of the workpiece and the bulge is straightened due to this stretching.
Editing by smoothing used in cases where the workpiece has a very small thickness. Smoothing is carried out with wooden or metal bars. The workpiece is smoothed on the correct plate, pulling the material with the help of trowels from the edge of the unevenness to the edge of the workpiece, and by pulling the material, the surface of the workpiece is leveled.
Tools and fixtures used in editing
Correct slabs made of gray cast iron with working surfaces
1.5×5.0; 2.0×2.0; 1.5×3.0; 2.0×4.0m. On such plates, profile blanks are corrected and
blanks from sheet and strip material, as well as bars from black and non-ferrous
Leveling grandmas used for straightening workpieces made of
high hardness metals or pre-hardened metals.
Leveling headstocks are made from steel billets with a diameter
200..250mm, their working part has a spherical or cylindrical shape.
Hammers when editing, they are used to apply force
effort at the place of editing. Depending on the physical and mechanical
properties of the workpiece to be processed and its thickness are chosen
various types of hammers. When straightening blanks from bar and
strip material, hammers with square and round
Soft hammers are used for dressing machined surfaces.
inserts made of aluminum and its alloys or copper.
Sledgehammers are hammers of large mass (2.0 ... 5.0 kg) and
are used for straightening round and shaped rolled products of large transverse
sections in cases where the force of impact applied by a conventional metalwork hammer,
insufficient to straighten the deformed workpiece.
mallets- these are hammers, the impact part of which is made of solid wood
rocks, they are ruled by sheet material made of metals of high ductility.
Feature mallet corrections in that they practically do not
Leave traces on the straightened surface.
Ironers metal or wood (from hard rock wood: beech, oak,
boxwood) are intended for straightening (smoothing) sheet material
small thickness (up to 0.5 mm). This tool is in the process of being processed
as a rule, does not leave traces in the form of dents.
Editing (straightening) - is a locksmith operation in which deformed, warped metal blanks or parts are given the correct flat shape. Editing is used after cutting sheet material with scissors, cutting with a chisel and other operations. With the help of straightening, strip and bar material, pipes and wires are also straightened. Cast iron parts are not subjected to dressing, since cast iron is too brittle and can crack when dressed.
In metalwork and especially in tool business, the correction of bent and warped products with great accuracy (up to tenths of a millimeter), after mechanical or heat treatment, often called product straightening.
Editing is manual and machine.
Pipes are bent manually or by means of a mechanism, with or without filler, in cold or hot condition. The choice of method depends on the pipe diameter, wall thickness, material and bending angle (Fig. 8).
Pipes with a diameter of more than 100 mm are bent in a hot state with a filler (fine dry sand). The ends of the pipes are closed with plugs and holes are drilled in them for the release of gases. Heating is carried out by a gas burner or blowtorch. Pipes with a diameter of up to 15 mm are bent using pins inserted into the holes of a steel plate, which is clamped in a vice. For thicker pipes, pipe benders are used, mounted on a special workbench. The pipe is inserted between two rollers at an emphasis. Bending the pipe by turning the lever with rollers by hand
Rice. eight Pipe bending: 1 - pipe, 2 - stop, 3 - template, 4 - movable bracket, 5 - roller, 6 - justification, 7 - lever
Copper and brass pipes are cold bent with filler (molten rosin, stearin, paladin, lead). The pipe is annealed before bending. Copper is heated to 600-700 °C and cooled in water; bronze - up to 600-700 ° C, in air; duralumin - up to 350-400 ° C, in air.
When heated copper pipes bent, filling with sand. Correctly bent pipes do not have folds and dents.
Workpiece Length Calculation
when bending parts at a right angle without rounding on the inside, the allowance for bending is taken from 0.5 to 0.8 of the material thickness. Folding length inner sides square or bracket, we get the length of the sweep of the workpiece.
Figure 4 a, b a square and a bracket with right internal corners are shown, respectively.
Square size: a= 30 mm; b =70mm G= 6mm. Workpiece development length l= a + b+ 0.5t 30+ 4+ 70 + 3 = 103 mm.
Staple dimensions: a= 70 mm b = 80 mm; With= 60 mm; t = 4 mm. Workpiece development length
l= a + b+ c + 0.5t = 70+80+60+2=212 mm.
a, b - squares and staples with right internal corners
A b
For manual dressing of sheet blanks and parts, steel or cast-iron straightening plates or anvils, steel hammers weighing 400-600 g, copper, lead, brass, wooden, bakelite, etc. hammers are used.
Machine dressing is carried out on manual and driven three-rollers, on driven pneumatic hammers and on presses. This manual deals only with manual dressing used in training workshops.
Editing is carried out by striking with steel hammers or hammers made of soft material in certain places, commensurate the force of blows with the size of the bulge and the thickness of the straightened product. The surface of the correct plate, as well as the heads of the hammers, must be even, smooth and well ground. When manually dressing, it is more convenient to use hammers with. round, and not with a square striker, since with incorrect blows or distortions of a hammer with a square striker, serifs or even holes may remain on the surface of the sheet. The hammer head should lie flat on the sheet, without distortion. The hammer should be held by the end of the handle and only the hand should be used to strike.
Techniques for editing sheet material are as follows. Having laid the deformed sheet on the plate, if possible with the bulges up, the bulges are circled with a graphite pencil or chalk. After that, frequent but not strong blows are applied along the straight edges of the sheet towards the bulge. The material under the action of impacts will be stretched, freeing the tightened middle and gradually leveling the bulge. As you approach the bulge, the blows should be delivered weaker, but more often.
After each hit, you need to check what effect it has on the sheet. It should be remembered that incorrect blows can cause the sheet to become unusable. In no case should you strike directly at the bulges, since the bulges will not decrease, but increase.
Thus, the essence of the process of straightening sheet parts is the gradual stretching of straight sections of the sheet due to some thinning of the material in these places.
Locksmith editing
To Category:
Metal bending and straightening
Locksmith editing
Editing is a method of processing workpieces with metalwork hammers or with the help of special devices in order to eliminate deviations in the shape and location of surfaces. The main purpose of editing is to reduce allowances for subsequent processing. To eliminated deviations include warping, dents, bulges, bends, twisting.
Rice. 1. Editing sheet blanks: 1 - workbench, 2 - straightening plate, 3 - places of impact, 4 - bulge, 5 - weak impacts, 6 - strong impacts, 7 - sequence of impacts
Concave and convex sides appear in the place of the defect on the workpiece. The fibers of the material on the concave side are compressed, and on the convex side they are stretched. Editing is done in order to equalize the lengths of the fibers of the convex and concave sides, stretching the concave side or compressing the convex side. The concave side is stretched by a purposeful impact of a hammer on it. At the center of impact, the material is plastically deformed (compressed). Along the edges of the shock zone, the particles of the material are displaced to the sides and the material is elongated, i.e., it is drawn out. A more significant drawing is achieved by hitting the narrow toe of the hammer, as this increases the pressure on the surface of the workpiece. When processing with a flat head of a hammer, the degree of drawing is less, and the hardening of the surface layer is higher.
Types of editing. AT plumbing apply cold and less often hot editing (manual and mechanized), carried out by stretching, untwisting, flexible and straightening.
Tools and fixtures for editing. The main tool for manual dressing are hammers. The most commonly used metalwork hammers with a round head and a convex sphere. A square head can leave dents on the workpiece. The striker must be ground, and when performing especially important work - polished. For straightening hardened steel sheet blanks, special hammers with a narrow rounded side of a hardened head or with solid high-strength inserts are used. Straightening of blanks from soft, thin and cleanly processed sheet material is carried out with hammers with inserts made of hard wood, copper, aluminum, lead, rubber, polyurethane.
As a strong non-deformable support for the workpiece, regular (steel or cast iron) plates with flat surface. They are installed on a solid and stable base.
To straighten billets from long products, various devices are used, for example, prisms, linings of various configurations, and a bench vise. Machine straightening uses presses various types(screw, hydraulic, pneumatic), straightening machines, horizontal stretching machines.
The sequence and methods of performing work when editing. First, the convex part of the workpiece is visually determined and its boundaries are marked with chalk or pencil. Then they choose the editing method, the necessary tools and fixtures, outline the editing scheme, places and sequence of impacts, their strength .. The thicker the workpiece, the stronger its material and the greater the deviation, the stronger the impacts should be. As the workpiece is straightened, the impact force should be reduced. In the process of editing, it is necessary to constantly evaluate the results of each impact and make the necessary adjustments to the intended processing scheme.
Hardened workpieces are placed on the correct plate during manual dressing. Then, with the toe of the hammer, uniform blows are applied along the edge of the concave side. Gradually, the force of the blows is reduced and they are applied, as it were, in the intervals between the places of the first blows. The material "accelerates" to the sides, the concave side lengthens and the workpiece becomes straight. Several successive blows to the same place can cause the appearance of new bulges, increased work hardening, cracks and breaks.
When editing sheet material with the most complex view work is to eliminate bulges. Attempts to eliminate them by hitting the bulge itself will lead to its increase. Processing is carried out with a flat hammer head so as to stretch the layers of material adjacent to the bulge. If the bulge is in the middle of the workpiece, then the blows are applied from the edge to the bulge, gradually reducing the force of the blows and changing their places. If there is a bulge on the edge of the workpiece, blows are applied from its middle to the bulge. The dressing of a workpiece with several bulges begins with blows in the intervals between the bulges in the direction of the bulges.
For large deviations in shape and big thickness and the strength of the workpiece material, the impact force of the hammer is not enough for straightening. In this case, the editing is carried out on the presses.
The metallurgy industry is actively developing, one of the most popular and common techniques in this area is metal bending and straightening.
What is the technology of the process of straightening and bending metal
Metal dressing - the process of eliminating shortcomings and defects metal billet. Defects can be considered bulges, waves on the surface, scratches, curvatures, as well as depressions. The essence of metal straightening operations is to compress the bulges on the surface and expand the depressions.
Editing can be carried out both when the metal is in a cold state and when it is heated.
The choice of the state of the metal during heating depends on the size of the defects, so, in case of serious damage to the surface, it will be easier to eliminate the defects when using hot straightening technology, and with small defects, it is possible to work with cold metal.
Dressing can be done by hand using steel or cast iron right stove, and can also be machine, it is carried out using a press.
The process of metal bending is very close to straightening. Bending is necessary to give the workpiece a curved shape.
The essence of this technology is that one part of the part is bent relative to the other at a certain angle. The action takes place under heavy load. In this case, it is important that the bending stress be greater than the elastic limit, and the deformation, which is a consequence of the load on the part, must be plastic. Otherwise, the workpiece will not retain its shape.
Types of metal straightening technologies
Editing and bending of metals can be of two types - manual and machine. Ductile metals such as copper and steel are subject to straightening and bending. Brittle metals cannot be edited.
Editing is necessary not only to eliminate defects, but also after welding, soldering and cutting blanks from a sheet under the influence of temperatures.
- Manual dressing Great for fixing minor imperfections. For its execution, tools such as sledgehammers based on cast iron and steel plates, as well as anvils are used. Requires a lot of effort.
- Typically used today machine straightening and bending. It provides a better result, in addition, this process is much easier. It is carried out with the help of presses and rollers.
For straightening, round-faced hammers, which have a strong handle, are best suited, and also sometimes use hammers and hammers with soft metal inserts. Bars are used for straightening sheets.
AT industrial scale only machine methods are used. The workpiece is passed between rollers that rotate in different sides. Under their pressure, the metal becomes even.
When using a press, the workpiece is placed on supports, then the press is lowered onto it, as a result of which the workpiece is also straightened. As a rule, with serious defects, the metal is corrected under the influence of temperatures. The optimum temperature for this is 350-450 degrees, you can’t heat it up anymore, since it can burn out.
When performing cold straightening, the temperature should be about 140 degrees. At a temperature of 0 degrees, it is impossible to edit, as the metal becomes brittle and breaks.
Metal straightening and bending processes are used everywhere. When bending, it is very important to correctly calculate the bend angle and proportions. For the quality of these processes, it is necessary good equipment- bending machines and presses.
Modern technologies of metal bending and straightening at the exhibition
In May, the metalworking exhibition "" will traditionally be held in Moscow. At this event, the world's leading engineers will present their developments.
The exposition will show high-quality and reliable newest machines for working with metals, and the presentations will explain innovative developments. The exhibition will be held at the Expocentre Fairgrounds.