As a result of bending or warping of the metal, some of its layers are stretched, others are compressed, and the cross section is rotated. To restore the original state of the metal, it is necessary to compress the stretched layers, and stretch the compressed ones. This is achieved various methods edits. Editing with impact load or pressure.

Prutkovy and strip metal driven with steel hammers. It is better to use round-faced hammers for this purpose: they make smaller dents on the surface of the metal. Blows are applied to a convex place: at first they are strong, as the blows are straightened, the blows weaken. The straightened bar (strip) turns from time to time so as not to get a bulge on the opposite side.

The quality of editing is checked with rulers, in irresponsible cases - by eye. Control can also be carried out on slabs: a poorly straightened strip (rod) will turn when pressed on the edges, an unstraightened round rod will give gaps in some places when rolled.

Round bars with a diameter of more than 30 mm, shafts and pipes are driven by screw presses. The part is placed in the prisms with the bulge up and pressed with a screw with a prismatic tip. For editing details various lengths the distance between the prisms can vary.

The quality of editing is checked by the indicator: the part is installed in the center and rotated. The deviation of the indicator needle will show the amount of non-straightness.

Machined surfaces, thin products made of steel and non-ferrous metals are driven by hammers with strikers made of copper, brass, lead, fiber, or steel hammers through gaskets made of soft materials. Small, thin parts can be straightened by clamping between the vise jaws.

Replaceable strikers Mallet 28 mm

Crooked strips are straightened by levers with forks. Often a hand vise is used for this purpose. They clamp the end of the strip protruding from the vise and, by rotating the lever, edit it.

To straighten the bent corner, it is placed in a prism, a hardened steel roller is placed between the shelves and, pressing the roller with the tip of the press, is straightened. Similarly, channels and other long products are corrected. Their straightness is checked with a ruler, on the plate along the clearance, the perpendicularity of the shelves is checked with a square.
Editing by drawing (straightening).

In a thin strip bent on an edge, a bent corner, a channel for straightening, it is necessary to extend the concave part. This is done with a hammer toe or special straightening hammers with two toes. A narrow toe creates a greater specific pressure that exceeds the yield strength of the material, and the metal "flows" - stretches.

Metal in the presence of a bulge (in this place the metal is stretched). Blows are applied with steel hammers or, if the sheet is thin, with wooden hammers - mallets from the edges towards the bulge. The edges are also stretched and the bulge disappears.

Reverse straightening hammer

If there are several bulges, they are first connected into one, striking between them. Straightening is also subjected to hardened objects that have received warpage during hardening. To do this, they are laid with a bulge downwards and light blows are applied with the toe, moving from the middle to the edges - thereby the compressed upper fibers are pulled out. If the angle has decreased during hardening, the blows are applied at the top inner corner, if it has increased - at the top of the outer corner. Hardened parts with a thickness of more than 5 mm, if they are annealed to an incomplete depth, can be edited as not hardened.

Thermal editing. In this case, the straightening of the metal is carried out by compressing the stretched side. The part to be straightened is placed with the bulge upwards. Curved place gets hot welding torch to cherry-red (neighboring parts of the metal are cooled with damp asbestos or wet rags). Since the heated metal is more ductile, when it is cooled by a jet compressed air the hot spot will shrink and the metal will straighten. This method is corrected by pipes, hollow shafts, profiled metal, forgings and castings, welded structures.

Hot straightening of metal. In parts with a sharp bend, large-section workpieces, in order to avoid cracks, the bent place is heated, after which it is straightened by pressure of the press or by hammer blows. The heating temperature depends on the material. For steel, it must be at least 850 and not higher than 1100 ° (exceeding this temperature will cause the metal to overheat). hot straightening only raw workpieces are exposed.

Chapter III

EDIT OF SHEET AND PROFILE SEMI-FINISHED PRODUCTS

§ 1. Manual editing of sheet and profile metal of a semi-finished product.

Editing in the centers. Manual editing on the plate.

Sheets arriving at the factory have dents, warping; strips, bars and profiles - non-straightness, section distortion.

The operation to eliminate these defects is called editing.

Real bodies, under the action of forces applied to them, to some extent change their shape and size, i.e. are deformed. The degree of deformation may be different.

If the body, as a result of the application of force, changes its shape, and then, after the termination of the load, restores its previous shape, then such a deformation is called elastic deformation. If, after removing the load, the body does not restore its previous shape, then such a deformation is called residual (plastic) deformation.

§ 1. Manual editing.

At manual editing apply universal tool and fixtures. Sheet blanks (semi-finished products) are corrected on regular plates, strips and rods - on plates, anvils.

Workpieces with raw surfaces are ruled with round-faced steel hammers, and with finished surfaces - with a copper or steel hammer through a thin copper or aluminum sheet. Thin sheets are ruled with wooden hammers, and very thin sheets with trowels. Hardened parts and blanks are driven by straightening hammers.

When editing, you need to choose the right places to hit. Impacts should be commensurate with the amount of curvature and gradually decrease as you move from the greatest bend to the least.

When straightening bars and strip material, the workpiece is placed with the bulge up (Fig. 15) and strong blows are applied to the bulge, turning the product from time to time. Finish editing with light strokes. Quality control of editing is carried out by eye or rulers.

Rice. fifteen. Manual dressing of strip material

If the thin strip is bent along the rib, the blows are applied with the toe of the hammer in rows, starting from the concave edge, and the blows should be stronger near the concave part (Fig. 16). Twisted strips are clamped in a vise and straightened with levers.

Rice. sixteen. Scheme of straightening strip material bent along the edge

The edges of strip blanks cut off on machines usually have a warped and wavy shape. Before editing, such defects are outlined with chalk or a simple pencil, the workpiece is placed on the plate and hammered in rows along the entire length of the strip, gradually moving from the lower edge to the upper one. At first, strong blows are applied, and to the upper edge, weaker and more often.

Strongly springy bars rule on screw presses(Fig. 17, b) or with the help of clamps (Fig. 17, a). In the first case, the bar is placed in a prism with the bulge up and pressed with a screw with a prismatic tip.

Rice. 17. Editing in centers: a - using clamps, b - screw press

The most difficult operation of manual straightening is the elimination of sheet metal defects. Two types of defects in sheet blanks are more common: waviness along the edges and bulges.

At straightening blanks, having waviness along the edges of the sheet (Fig. 18), strikes are applied from the middle to the edges. In this case, the strongest blows should be delivered in the middle, and as you approach the edge, the impact force gradually decreases. Very thin sheets are leveled by running a trowel over them (Fig. 19).

Rice. eighteen. Scheme of distribution of impacts during manual dressing on the plate

Rice. nineteen. Editing a wet sheet by smoothing

Bulges are most often found over the entire surface or in the middle of the leaf. Before editing, the bulges are circled with chalk or pencil, then the workpiece is placed on the leveling plate with the bulges up. The workpiece dimensions must be smaller sizes plates.

After installing the workpiece on the plate with a hammer, a series of blows are applied from the edges to the bulge (Fig. 20). The blows should weaken as you approach the bulge. Editing usually starts from the closest edge to the bulge, then proceeds to the second edge, and so on. If there are several small bulges on the surface of the workpiece and they are closely spaced from each other, then in this case they are merged into one with hammer blows at the edges of individual bulges and then corrected as described above.

Rice. 20. Scheme of manual dressing of sheet metal on a workpiece plate with bulges

The hardened parts are corrected (aligned), putting the bulge down and inflicting weak frequent blows from the middle to the edges. Products with a thickness of more than 5 mm with a viscous core are ruled as not hardened. Depending on the type of straightening, various straightening hammers are also used. When straightening precise parts where hammer marks are unacceptable, light hammers are used. If metal should be pulled out during straightening, steel hammers weighing 200-600 g or special straightening hammers with a rounded narrow side of the striker are used.

Deformed welded sheet structures rule by striking from the side of the depressions, and not from the side of the bulges.

The walls of the welded box are straightened by striking the inside of the box. But since in this case it is impossible to completely straighten the sheet, then with a slight decrease in the bulge, a strong blow of the hammer creates a bulge on the reverse (outer) side and continues to strike from the inside along the edge (corner) of the box.

For straightening welded structures, as well as some special parts, various screw fixtures are used.

Editing (straightening) - is a locksmith operation in which deformed, warped metal blanks or parts are given the correct flat shape. Editing is applied after cutting sheet material 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 plumbing 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, is 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 straightening 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.

In his practical work a locksmith is often faced with the editing of metal of a particular profile or with the editing of blanks.
Editing is a preparatory operation. It can be done in two ways: mechanically- using correct rolls, presses and various devices and manual - using a hardened steel hammer, sledgehammer, anvil or plate and auxiliary tool- ironers.
When manually straightening, it is better to use a hammer with a round face to prevent nicks and dents on the surface of the straightened workpieces. The surface of the hammer head must be carefully sanded.
For dressing parts with a finished surface, as well as thin steel products or workpieces made of non-ferrous metals and alloys, hammers made of soft materials are used - copper, brass, lead, wood.
When editing fine wire and thin strip and sheet metal, metal and wooden mandrels, floats and gaskets are used.
Editing of strip and sheet material. When straightening a curved strip, the latter is held with the left hand and, on an anvil or plate, strikes with a hammer at the convex places of the wide side of the strip, turning the strip from one side to the other as necessary.
The impact force is adjusted depending on the magnitude of the curvature and the thickness of the strip.
After finishing the editing of the wide part of the strip, they begin to edit the edge, first with strong blows, and then with weak ones, turning the strip after each blow from one edge to another.
Checking the straightened strip is done by eye, and more precisely - with a ruler or on a marking plate.
Editing of thin strip steel is carried out in a different way, since from hammer blows on a convex rib, a thin strip will bend to the sides, and the places in contact with the plate will stick together.
A thin strip is corrected on a plate: pressing it with the left hand, with the right hand strikes with a hammer along the entire length of the strip, gradually moving from the lower edge to the upper one, as indicated in Fig. 69.

In the beginning, the blows should be strong, and as you move to the upper edge, they should be weaker, but more often applied. Such editing helps to stretch the lower edge, and the strip becomes even.
Editing sheet material is a more complicated operation, since the bulges on the sheets in most cases are in the middle or are scattered over the entire surface of the sheet, and when you hit the convex parts with a hammer, the latter will not only not decrease, but even increase in size.
Therefore, editing sheet material should be carried out as follows:
The sheet is placed on the stove and the bulges are outlined with chalk or pencil. While supporting the sheet with the left hand, the right hand strikes with a hammer from the edge of the sheet towards the bulge, as shown in Fig. 70 arrows. Blows should be applied frequent, but not strong. Under the influence of such blows, the flat part of the sheet will increase, and the bulge will gradually straighten.

As you approach the convexity, the blows should be made more often and weaker, at the same time it is necessary to monitor whether the surface of the sheet improves, whether there are traces of hammer blows on it and whether the convexity is eliminated.
If there are several bulges on the sheet, then blows should be applied in the intervals between the bulges, as a result of this, the sheet is stretched and all the bulges are reduced to one common bulge, which is straightened in the usual way, i.e. going from the edges of the convexity to the middle. After that, the sheet is turned over and with light blows of the hammer, its straightness is finally restored.
Very thin sheets are leveled on a flat and smooth plate.
Straightening of bar material and shafts. Long rods and wires are straightened by passing through dies in broaching machines or through rotating rollers in a special straightening machine, or by hand on a plate. Short workpieces are also ruled in this way. Checking the straightness of bars and blanks is carried out on the plate or by eye.
Shafts and billets of large cross section are straightened manually or mechanical press, for which the shaft or workpiece is installed on the prisms of the press table with the convex part up. The distance between the prisms is adjustable.
Usually it fluctuates between 150 - 300 mm. Editing is carried out by pressing the screw on the convex part of the shaft.
Shafts of large cross-section and with a significant deflection are preheated in places of maximum deflection.
Checking the shaft after dressing is carried out in centers mounted on a separate table or plate, as indicated in Fig. 71.

Editing hardened parts. Warped steel parts or blanks after hardening are ruled by special steel hammers, the striking part of which has the shape of a metalworker's hammer, carefully processed, without sharp corners and well hardened. The dressing plate must have a smooth ground surface (flat or convex), the hardness of which must not be lower than the hardness of the hammer head.
Hammer blows should be applied not to the convex part of the hardened part, but to the concave part. In this case, the blows should not be strong, but frequent.
For example, let's take a look at several cases of straightening hardened parts.
The part is placed on the convex surface of the plate and, holding it with the left hand, apply light but frequent hammer blows to the concave part, starting from the most concave part and gradually moving to the place where the deflection ends.
At the same time, the part is turned by 15 - 20 ° with the left hand, either in one direction or the other, and moved towards itself. Thus, the impacts are distributed over the concave surface of the sector with an angle of 30 - 40°.
As a result of this, the fibers of the concave part of the part seem to be distributed, stretched from hammer blows, and in the convex part they are compressed and the part is leveled.
In a similar way, the hardened strip of the ruler is corrected (Fig. 72).

In the case when a flat part has cutouts, for example, a bracket, a template, then it warps during hardening (both along the plane and along the edge), and therefore editing should be carried out in the following sequence:
The template is placed with its convex part on the plate and held with the left hand at one end, and right hand apply frequent, but not strong blows to the concave part with the toe of the hammer, starting from the middle and gradually moving to the edge. Then, taking the opposite end of the template with your left hand, continue editing the second part of the template in the same sequence.
After editing the plane, they start editing along the edge. In this case, the template or bracket is pressed against the plate with the left hand, and the right hand strikes with the toe of the hammer from the side of the concave part from the middle to the edge alternately on both sides (Fig. 73).

Dressing hardened rollers and spindles with a diameter of 20 mm and above usually produce hand press by pressing the press screw on the convex part of the part.

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 located on correct plate bend upwards and blows are applied to 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 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.