First, use common tools and equipment correctly.
The commonly used tools for manual correction are various hammers, such as platforms and mats. , can correct the steel with smaller size and less serious deformation.
(1) The hammer head of the hammer has various shapes such as round head, straight head and horizontal head, among which the round head hammer is the most common.
The specifications of the hammer are 0.5, 0.75, 1kg according to the weight of the hammer head. The wooden handle is solid Fraxinus mandshurica, about 300~350mm long, and it is tightened with an iron wedge after being loaded into the hammer. Before using the hammer, check whether the hammer is firmly installed to prevent the hammer from falling off and hurting people.
(2) There are three kinds of hammer heads: flat head, straight head and horizontal head, and the flat head hammer is the most used in the rectification process.
The specifications of the sledgehammer are also divided according to the weight of the hammer head, including 4kg, 5kg, 5kg and 8kg. The length of the wooden handle is about 1000~ 1300mm, which can be selected according to the height and working conditions of the operator. Before each use, check whether the hammer is firmly installed and slightly loose, and tighten the iron wedge with inverted teeth, otherwise it shall not be used.
Precautions in the use of sledgehammer: sledgehammer is a heavy manual labor operation, which is dangerous to some extent. So be sure to pay attention to safe operation. 1 Before operation, strictly check whether the hammer is firmly installed, and check it at any time during intermittent operation. If it is found loose, it should be reinforced immediately, otherwise it will not be.
You have to use it. (2) The hammering work site should have sufficient operating space. When lifting the hammer, check whether there are people or obstacles before and after, and lift the hammer only after there is no abnormality. (3) Observe the operation procedures, and it is forbidden for the operator to wear gloves and hit a sledgehammer. (4) When two or more people operate at the same time, there should be primary and secondary coordination, no relative sledgehammer, and the standing position should be on the same side of the workpiece. ⑤ Soft hammers, such as wood hammers and copper hammers, are often used when correcting thin steel plates, nonferrous metal materials or workpieces with high surface quality requirements.
Second, the mechanical correction of steel deformation
1. Correct the bending deformation of section steel with a press.
A) First, find out the curved part of the section steel and put its convex surface on the press.
B) Pad blocks on both sides of the protruding part of the lower part of the section steel, which should be consistent with the outer surface of the section steel if necessary.
C) Operate the control switch of the press, so that the slider of the press slowly descends, and exert pressure on the convex part of the section steel. When the large steel is straightened, the slider of the press is lifted to observe the rebound of the section steel, and then the press is operated to press down, so that the corrected steel will have a little downward concave bend to offset the rebound until the section steel is straightened.
2. Correct the angular deformation of angle steel with a press.
A schematic diagram (not shown) of correcting the deformation of angle steel with a 90 bending die on a press. During operation, the two pads under the angle steel should be straight and equal in thickness, and the thickness should not exceed the thickness of the edge of the angle steel, and the length should be equal to or exceed the longitudinal length of the tool. When placing the shim, it should be placed in a symmetrical position. You can operate the press to make the punch gently press the angle steel and adjust the position of the shim. After adjustment, the press can be operated to press down, and the deformation of angle steel should be observed during the press down until the angle steel is corrected.
3. Correct the deformation of channel steel (as shown in the figure) with a press as follows:
A) Underneath the two corners where the channel steel contacts the platform, a pad should be placed, and the thickness of the pad should be greater than the possible rebound.
B) Place a square steel on two corners of the channel steel.
C) Manipulate the press to press down, and apply force to the channel steel through the square steel to correct the distortion in the opposite direction.
Third, mechanical correction of steel plate deformation
(1) Correcting the bending deformation of section steel with a press as shown in Figure 6- 10. This paper introduces the specific operation method of correcting the deformation of section steel with a press.
1) First, find out the curved part of the section steel, put the convex surface up and put it on the press.
2) Pad the two sides of the protruding part at the lower part of the section steel. When necessary, the pad should be consistent with the outer surface of the section steel.
3) Operate the control switch of the press, so that the slider of the press slowly descends and exerts pressure on the convex part of the section steel. When the section steel is pressed straight, lift the slider of the press to observe the springback of the section steel, and then operate the press to press it downward, so that the corrected section steel is slightly concave to offset the springback until the section steel is straightened.
(2) Correcting the angular deformation of angle steel with a press Figure 6- 1 1a is a schematic diagram of correcting the angular deformation of angle steel with a 900 bending die on a press. During operation, the two pads under the angle steel should be straight and equal in thickness, and the thickness should not exceed the side thickness of the angle steel, and the length should be equal to or exceed the longitudinal length of the mold. When placing the shim, it should be placed in a symmetrical position. You can operate the press to make the punch gently press the angle steel and adjust the position of the shim. After adjustment, the press can be operated to press down, and the deformation of angle steel should be observed during the press down until the angle steel is corrected.
Fig. 6- 1 1b is a schematic diagram of correcting the deformation of angle steel with a 900 bending die on a press. The operation method is the same as above. If the longitudinal length of the die is sufficient, it can also be used to correct the bending or twisting deformation of angle steel.
(3) Correct the distortion of channel steel with a press. The specific operation is as follows:
Plating steel plates under the two corners where the channel steel contacts the platform, and the thickness of the steel plate is greater than the possible rebound. Put a square steel on the two corners of the channel steel. Operate the press to press down, and the square steel acts on the channel steel to correct the distortion in the opposite direction.
Four, mechanical correction of steel plate deformation
1. multi-roll straightener corrects steel plate deformation.
Multi-roller straightener is a special equipment used to correct the deformation of steel plate, which is mainly composed of frame and two rows of shaft rollers. The shaft rollers of the leveler used to level thick steel plates are few in number and arranged gradually, which can make full use of the capacity of the equipment, and the right end is the steel plate outlet.
There are many rollers on the straightener used to straighten thin plates. Because the required straightening force is small, the upper and lower rollers are mostly arranged in parallel, so that the steel plate can be fully bent and extended until the steel plate is straightened.
Operation method of straightening machine for correcting steel plate deformation
A) Adjust the shaft rollers, find a steel plate with the same thickness as the corrected steel plate, put it between the upper roller shaft and the lower roller shaft, and adjust the adjusting handwheels at both ends of all upper roller shafts to make the adjustment effective.
All the upper shaft rollers press the steel plate, and then start the straightener to push the steel plate out, so that the position of the upper shaft rollers can be adjusted. Press the handwheel to make the shaft roll rotate once.
The adjustment amount of the handwheel of each shaft roller can be distributed according to the descending height, and the rotation angle of the handwheel can be increased from the outlet in turn as needed.
So that the upper shaft rollers are gradually arranged. The picture on the right is 20 mm
Reference dimensions for vertical spacing of rollers. The first upper shaft roller at the entrance of the left steel plate is connected with the first shaft roller and the second shaft roller.
The vertical spacing of the lower roller shaft is equal to the thickness of the steel plate, which is convenient for feeding. export
Straight man.
B) Trial Rolling Through the first trial rolling, you can check whether the upper and lower shaft rollers are arranged correctly. If the corrected steel plate is straight and there is no concave-convex phenomenon, that is,
The split shaft roller has been adjusted correctly. During trial rolling, the steel plate is prone to low warping. When the steel plate at the exit is lowered, you can put the steel plate at the exit first, and then put the steel plate at the exit.
Fine-tune the upper shaft; When the outlet steel plate inclines upwards, the first upper shaft roller at the outlet can be finely adjusted downwards. Until it rolls out the exit.
The steel plate is straight.
C) Straightening the steel plate on a straightener sometimes requires repeated rolling. In practice, for the parts with serious local outburst,
The method of thinning the gasket can be used to obtain greater correction force in the convex part. Specific operation: take a quick thickness of about 2mm, and the size is just right.
The thin steel plate covering the convex part is placed on the convex part of the steel plate to be corrected and enters the shaft roller together with the steel plate to be corrected. Because the thin steel mat here
Action, so that the correction force is concentrated on the convex part of the steel plate to be corrected, so as to flatten it. For thin steel plate correction, a slightly larger thickness can be used.
The steel plate is used as a liner for calibration. The specific method is: select a flat thick steel plate as a gasket, put the straightened thin steel plate on it and adjust the upper shaft.
Roller, so that it can pass through the shaft roller, and then send the thick steel plate and thin steel plate to the straightener for correction. For batch correction of small workpieces,
You can also refer to the above method for centralized correction, but pay attention to the thickness of the corrected workpiece and the edge of the cut or cut workpiece should be clear.
Burr, otherwise it will damage the shaft roller.
2. The plate bender corrects the deformation of the steel plate. Plate bending machine is a device used to roll cylindrical or arc workpieces. The most common is the three-axis plate bending machine, whose shaft and roller are symmetrically arranged.
The operation method is as follows:
A) placing a steel plate to be straightened between an upper roller and a lower roller, downward adjusting the upper shaft roller to press the steel plate, starting a plate rolling machine to crush the steel plate, and in the process of repeated rolling,
Lower the upper shaft roller downward to make the steel plate roll out at a proper arc. In this process, the irregularly deformed steel plate becomes a regular arc steel plate.
B) Turn the steel plate over, readjust the upper shaft roll, place the convex surface of the arc steel plate upward between the upper shaft roll and the lower shaft roll, put down the upper shaft roll, and roll repeatedly until the steel is pressed down.
Flat leveling.
4. Manual correction of steel plate deformation
A) Manual correction of steel plate deformation When hammering a steel plate, the elongation of the steel plate is not easy to grasp, so the steel plate deformation is corrected manually.
It is difficult to correct, and it is a basic operating skill that is not easy to master.
For the deformation of thin steel plate, we can imagine that it is caused by the inconsistency between "looseness" and "tightness" of its internal structure. Manual hammering is used to correct the deformation of thin steel plate, which is to extend the "tight" part and make it reach a new balance with the "loose" part to achieve leveling.
Correction of the deformation of the bulge in the middle of the steel plate for this deformation, it can be considered that the steel plate is loose in the middle and tight around. When correcting, hammer the parts tightly so that
Expands to offset the contraction of the constricted area.
Correction of local convex deformation correction of surrounding undulating deformation
In the process of operation, we should pay attention to the following two points:
1. When hammering, it spreads outward from the convex edge, and the density of hammering points becomes denser outward, so that the periphery of the steel plate is fully expanded.
2. Don't directly hammer the convex part, because the steel sheet has poor rigidity. When hammering, the convex part will be pushed down and expanded, which will easily make the deformation more serious. ? Correction of fluffy deformation around steel plate For this deformation, it can be regarded as a steel plate with four Zhou Song in the middle. When correcting, you can
On the platform, starting from the convex edge, the tighter parts are hammered inward, and the density of hammering points becomes denser inward, so that the tighter area in the middle of the steel plate is filled.
Divide and extend until it is leveled.
Correction of irregular deformation of thin steel plate is sometimes difficult to judge loose and tight areas at once. At this time, according to the deformation of the steel plate,
Ring hammer is carried out on a certain part of the steel plate to make irregular deformation become regular deformation, and then the loose and tight parts are judged and corrected.
B) Manual correction of thick plate deformation Thick steel plate is stiff and difficult to manually correct. But it is also necessary for some small workpieces made of thick steel plates.
It can often be corrected by hand.
The convex surface of the bent steel plate is buckled on the platform by direct hammering, and the convex surface of the steel plate is directly hammered by a sledgehammer. When the hammering force is large enough,
The bulge of the steel plate can be compressed to produce plastic deformation, so that the steel plate can be corrected.
In the method of expanding the concave surface, the convex surface of the bent steel plate is placed down on the platform, and the concave part of the steel plate is strongly hammered to expand its surface and obtain straightening.
Ping.
In actual production, when the width of steel plate is large and it is difficult to correct it by other methods, it is usually to install a flat punch on the air gun instead of hammering to enlarge the concave surface. This method is effective, but it is noisy, and it is easy to damage the surface of steel plate and make it rough.
Five, local heating correction
Local heating correction, also known as flame correction, is an important means to correct rigid deformation and structural deformation. The principle of local heating correction is to make use of the physical characteristics of thermal expansion of metal materials. The specific process is: local heating is carried out at the deformed part of steel, and the heated material expands due to heat. However, due to the low temperature around the unheated part, the expanded part of the material undergoes compressive plastic deformation and the expansion is blocked. After stopping heating and cooling, the material in the expansion position shrinks, which drives the steel to produce new deformation. By using and controlling the deformation caused by heating-cooling in the opposite direction to the original deformation, the original deformation can be offset. The key to control the deformation direction of heating-cooling is to correctly determine the heating position and choose the appropriate heating zone shape.
1. Selection of heating zone shape There are three heating zone shapes for local heating: point heating zone, linear heating zone and triangular heating zone. Because of the different size and shape of the heating zone, it has different shrinkage characteristics.
1) point heating is a circular point with a certain diameter at the heating place, and one or more points can be selected according to the needs of steel deformation. Multipoint addition
When it is hot, the hot spots are mostly arranged in plum blossom shape.
The characteristic of point heating is that the thermal expansion shrinks to the center of the point after cooling. According to this feature, when the steel plate is deformed locally, it can be considered that the internal structure of the bulge is "loose" and bulged. Select an appropriate number of heating points at the bulge, and shrink evenly after cooling to get leveling. Point heating is suitable for correcting the deformation of thin steel plate.
The operating points of point heating are as follows:
The size and arrangement of heating points should be uniform, and the diameter of the points depends on the thickness of the steel plate to be straightened, and generally should not be less than ⊙15 mm.
There should be obvious boundaries between heating points, and the distance between points is generally 50 ~100 mm.
When the primary heating fails to meet the calibration requirements and needs to be repeated, the heating point shall not coincide with the last heating point.
2) Linear heating means that when heating, the flame moves in a straight line direction or swings horizontally in the width direction at the same time, and the heating area is a strip area with obvious difference in length and width.
The characteristic of linear heating is that after cooling, the transverse shrinkage of the heating zone is much greater than the longitudinal shrinkage. Linear heating is rarely used to correct steel deformation. In the structural parts with large deformation, it is sometimes selected according to its deformation characteristics. The width of linear heating depends on the thickness of the plate, and the thickness of the plate is generally selected.
1~3 times.
3) The triangular heating area is an isosceles triangle, and the bottom plate is at the edge of the steel plate or structural member. This heating method is called triangle heating.
The characteristics of triangle heating: because of the large heating area, the shrinkage is also large, and because the heating width of triangle along the height direction is not equal, the shrinkage is not equal. Starting from the apex of the triangle, the contraction gradually increases along the two waists. Because the triangle heating area has a large shrinkage and a certain change law, this heating method is often used to correct the deformation of steel structure.
The operation points of triangle heating are as follows:
1. The triangular shape of the heating zone should be obvious and isosceles. The top angle should be less than 60, and the bottom edge should be at the edge of the straightened steel or parts. ? The heating area should be heated evenly, the back should be baked thoroughly, and the front and back sides can be heated alternately, but pay attention to the shape and position of both sides.
2. Precautions in heating operation No matter which heating zone shape is selected, the following points should be paid attention to when heating:
The heating speed should be fast, the heat should be concentrated, and the heating range outside the heating area should be minimized. This can improve the correction effect and obtain greater correction effect locally.
Shrinkage.
When heating, the welding nozzle should be shaken in a round or linear shape, not just baked a little, so as not to burn the corrected steel.
When the local heating correction needs to be repeated after the first correction, the heating zone shall not overlap with the previous heating zone.
In order to speed up the contraction of the heating zone, hammering is often supplemented, but a wooden hammer or a copper hammer is needed, and a hammer is not allowed.
In order to speed up the cooling rate, water quenching can be used, but attention should be paid to correcting the material quality. Materials with hardening tendency (such as medium carbon steel and low alloy structural steel) are not suitable for water quenching. When the cooling rates of the surface and the interior of thick materials are inconsistent, cracks are easy to occur at the joints, which is not suitable for water quenching.