JPS62244525A - Manufacture of dissimilar shaped sectional bar - Google Patents

Abstract

PURPOSE:To reduce a manufacturing cost and to improve production efficiency by bending a plane shaped member in U shaped sectional shape and deforming both side walls with their ironing, then by forming the side wall part in a plane shape by re-bending it. CONSTITUTION:Bending stands A, C, and ironing stands B, D are arranged in the order of A, B, C, D and re-bending stands E, F are set up in succession to the stand D as well. An U shaped material Ma is formed by bending a plane shaped stock M at the 1st bending stand A and the U shaped member Mb is formed by ironing a side wall part Wa at the 1st ironing stand B. After form-a member Md at the 2nd bending stand C and 2nd ironing stand D similarly, a dissimilar sectional bar is obtd. at the re-bending stands E, F. Since the product of good quality can continuously be manufactured with less stands the production cost is reduced and production efficiency is improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to irregular cross-sectional strips having a convex or concave cross-sectional shape, that is, a thick section and a thin section extending in the longitudinal direction. The present invention relates to a method of manufacturing a strip of irregular cross section having a section.

[Prior Art] Conventionally, known manufacturing methods of this type include a cutting method, a rolling method, and an intermittent manufacturing method using a V-shaped die and a flat roll.

The cutting method involves cutting off a part of a material with a rectangular cross section that has the same thickness as the thick part to form a thin part.
It manufactures strips with irregular cross-sections.

Further, there are the following two methods of rolling processing. One is to extrude a material with a thickness ratio that is almost the same as the thickness ratio of the final irregular cross-sectional part from billet material, etc., and then roll this material while keeping the thickness ratio of each part of the cross-section almost the same. This is the way to do it. Another method is to roll a flat material in multiple stages using multiple rolls that gradually change the shape and dimensions of annular projections formed on the outer periphery, and gradually expand the width of the projections or recesses. It's something to do.

Furthermore, the interrupted manufacturing method uses a V-shaped die having a flat plate portion and a V-shaped convex portion on the upper surface of the flat plate portion that gradually becomes wider from one end to the other end, and a flat roll having a cylindrical shape. A material having a rectangular cross section is repeatedly passed through the V-shaped protrusion from the narrow side several dozen times between the
By forming thin-walled portions in this way, strips with irregular cross-sections are manufactured (Japanese Patent Publication No. 7302/1983).
.

[Problems to be Solved by the Invention] However, each of the conventional manufacturing methods described above has the following problems.

That is, in the manufacturing method using cutting, a part of the material is shaved off, so there is a problem that material loss is large and the yield is deteriorated.

In addition, in the first method using rolling, if the thickness reduction rate of the thick and thin parts is not the same, distortion will occur due to the difference in elongation between them, and internal stress due to this distortion will occur. As a result, cracks or wrinkles occur in the manufactured irregular cross-section strip. Therefore, when manufacturing materials, it is necessary to accurately form the parts that should be thick and the parts that should be thin so that the difference in thickness between them is a predetermined value. It is not easy to manufacture such a material, so it was not a practical method.

On the other hand, in the second method, it is possible to prevent the difference in plate thickness due to processing from becoming a difference in elongation only by repeating local processing, so many pairs of rolling rolls are required, which increases tool costs. There was a problem.

Furthermore, in the intermittent manufacturing method, it is necessary to move the roll forward and backward relative to the material dozens of times. Here, since no processing is performed when the roll is retracted, there is a problem that the time required for retracting becomes loss time, resulting in poor manufacturing efficiency.

=31 In view of the above-mentioned problems, the object of the present invention is to manufacture a strip of irregular cross-section that has a high material yield, good manufacturing efficiency, and low material cost.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a method for manufacturing a strip of irregular cross-section having a thick part and a thin part extending in the longitudinal direction. a bending process in which the flat plate-shaped member is bent so that the cross section becomes U-shaped; a ironing process in which both side walls are strained and deformed to make it thin; and then, the side walls are bent back to form a flat plate shape. This configuration includes a returning step.

[Operation] In this manufacturing method, a flat plate member is bent into a U-shape, the side wall part thereof is ironed, and then bent back, thereby forming irregular cross-sectional strips with different thicknesses along the width direction. This manufacturing method is applied to a roll having an annular groove formed therein, and a roll protruding and fixed into the annular groove, and having a rectangular cross section.

By moving the strip in the longitudinal direction using a processing stand equipped with fixed rolls or fixed molds, long irregular cross-section strips can be continuously manufactured. Since the deformation in the side wall portion is limited to the plane perpendicular to the direction of movement of the material (a state of so-called plane strain), even if the thickness reduction ratio per process is relatively large in thin-walled portions. Warping and cracking of thin parts is less likely to occur.

[Example] Hereinafter, an example of the method of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows the apparatus and processing steps of the first embodiment of the present invention. In this figure, the upper row shows the apparatus, A is the first bending stand, B is the first ironing stand, and C is the second ironing stand. The bending stand, D is the second ironing stand, E is the first unbending stand, and F is the second unbending stand. Also,
The lower row shows the cross-sectional shape of the material after passing through each stand.

The above-mentioned bending stands A, C and ironing stand B1D have almost the same structure, and each of the two side rolls I a
, ] b, 1 c, I d and lower mold 2 a,
2 b, 2 c.

It consists of 2d.

As shown in FIG. 2, these rolls Ia, Ib... are formed with annular grooves 3a, 3b whose cross section is shaped like an opening, and grooves are formed at the corners of both side walls 4a, 4b... is the chamfered portion 5a
.

5b... are formed to facilitate bending.

On the other hand, the molds 2 a, 2 b... have their upper parts connected to the annular grooves 3 a, 3 b of the rolls I a, l b...
..., and its vertical cross section perpendicular to the direction of movement of the material is a rectangle that is slightly smaller than the cross section of the annular grooves 3a, 3b. This mold 2a, 2b
... The distance Q between the upper surface of the annular grooves 3a, 3b... is set equal to the thickness of the material (same thickness as the thick part of the product), and the distance between the molds 2a, 2b... end face and annular groove 3a,
3b... is set equal to the above-mentioned ρ in bending stands A and C, and set to the thickness after thickness reduction in ironing stands B and D. In addition, the molds 2 a, 2
As shown in FIG. 3, b... is tapered at the front and back of its upper surface to smooth the running of the material.

The above-mentioned unbending stands E and F are for restoring the bent material into a flat plate shape, and each consists of a pair of upper and lower rolls 6 e, 7 e and 6 f, 7 f. A cavity in the shape of a V-shaped upper part connected is formed between the rolls 6e and 78, and a linear cavity is formed between the rolls 6f and 7f of the second unbending stand F.

A coiler (not shown) for winding up the product is provided behind the second unbending stand F.

Next, a method for manufacturing a convex irregular cross-section strip having a thick portion at the center in the width direction of the plate using the manufacturing apparatus configured as described above will be described.

As the material M, a long thin plate coil is used, the thickness of which is equal to the thickness of the thick part of the product, and the cross-sectional area of which is set slightly larger than the cross-sectional area of the product.

This material M is bent into a U-shaped material Ma by a first bending stand A in the width direction of the material M at approximately half the position corresponding to the original thin-walled portion, and then by a first ironing stand B. Both side wall portions Wa of the character-shaped material Ma are iron-formed to form a U-shaped material Mb having a thin wall portion wb. And the second
A similar process is performed using the bending stand C1 and the second ironing stand D to form a U-shaped material Md having a thick part Td and a thin part Wd having the same width as the product. This U-shaped material Md is bent back by bending stands E and F to form an irregular cross-sectional strip having a thick wall portion T in the center and thin wall portions W on both sides.

In addition, in this example, the prescribed thickness is reduced by ironing twice, but this is because if a large thickness reduction is performed at one time, a buckling deformed part called an edge will occur in the thin wall part. Depending on the properties of the material, the shape of the product, etc., it may be possible to do it in one go.

Next, a method for manufacturing a strip with a concave irregular cross section that is thin in the center in the width direction will be described with reference to FIG. In this case, a U-shaped material Ma' is formed by bending the material M' with a bending stand A, and edges Tb', , Tb' of the side walls Wa', Wa'' are further bent with an ironing stand B. By ironing leaving , thin parts wb', wb
At this time, the width of the edge T b' is set to half the width of the thick part Tb't in the center.The U-shaped member Mb° thus formed is bent back and E, F
The irregular cross-section strip S° is bent back by the following steps and has two thin-walled portions w' and w'.

is formed, and further divided into two at the center to produce two concave irregular cross-section strips s', s',.

In addition, in the above, bending and squeezing are performed using separate stands, but it is also possible to perform these using the same stand.

FIG. 5 shows a third embodiment of the present invention, in which bending stands G and L bending stands H are provided with rolls 1 and 1 on both the upper and lower sides.
It is composed of g, 2g, 1h, and 2h. The cross-sectional shape of each roll is the same as that shown in FIG. In this case, the material M is the lower roll 2.
Since it is easy to wrap around the material M, tension is applied to the material M (for example, by pulling the coilers 8a and 8b on both sides) to prevent the material from wrapping. In this case, applying this tension will promote the unbending process.

FIG. 6 shows a fourth embodiment of the present invention, and is an example in which both molds are common, considering that the cross-sectional shapes of the lower molds in the bending process and the ironing process are the same.

That is, each upper roll lk is attached to the same lower roll 2k.
, Ip are combined to form a bending and ironing stand K.

According to this example, the structure is simplified, the lower roll 2k can be made larger, and the above-described winding deformation is less likely to occur, so that the deformation ratio can be increased.

FIG. 7 shows a fifth embodiment of the present invention, in which a bending stand Q and an ironing stand R are lowered by 1 to the fixed lower molds 2q and 2r and the lower molds 2q and 2r, respectively.
It is composed of one mold 1q and Ir. In this example, the material M is moved intermittently, bent,
By performing the bending back process, sufficient processing can be performed.

[Effects of the Invention] As described in detail above, the present invention provides a method for manufacturing a strip of irregular cross section having a thick portion and a thin portion extending along the longitudinal direction, the method comprising manufacturing a flat plate member having a U-shaped cross section. Shape-11~ This is a diagram showing a culm. A bending process of bending it so that it becomes like this, an ironing process of straining and deforming the both sides of the culm to make it thin, and then bending the side walls back to form a flat plate. Since the structure includes an unbending step to form the material into a shape, deformation in the wall portion is limited to a plane perpendicular to the direction of movement of the material, and the reduction ratio per one time in thin-walled portions is reduced. Even if the thickness is relatively large, warping or cracking of thin parts is less likely to occur. Therefore, the number of stands for processing is small, the cost of tools is low, and manufacturing is possible in a continuous process, resulting in high production efficiency. The material loss is only due to the cutting of the edges, so the yield is good, and the dimensional accuracy of thin-walled parts is also high.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the apparatus and process of a first embodiment of manufacturing according to the method of the present invention, FIG. 2 is a cross-sectional view of the main parts of the above-mentioned apparatus, FIG. FIG. 5 is a diagram showing the processing steps of the second embodiment, FIG. 5 is a diagram showing the apparatus and process of the third embodiment, FIG. 6 is a diagram showing the apparatus and process of the fourth embodiment, and FIG. 7 is a diagram showing the fifth embodiment. A, C, G, Q...Song (Destand, B, D, H, R...Shigoki Stand, K
...Bending and ironing stand, E, F...
・Bending stand, Ma, Mb, Mc, Md, Ma'
, Mb' -- U-shaped member, v4'... Thin wall portion, T, T'... Thick wall portion.

Claims (3)

[Claims] (1) A method for manufacturing a strip of irregular cross section having a thick part and a thin part extending along the longitudinal direction, which includes a bending step of bending a flat plate member so that the cross section becomes a U-shape, and both sides thereof. An ironing process that irons and deforms the wall to make it thinner;
A method for manufacturing an irregular cross-section strip, the method comprising the step of bending back the side wall portion and forming it into a flat plate shape. (2) The method for manufacturing irregular cross-section strips according to claim 1, characterized in that the ironing step is carried out by repeatedly pressing a tool parallel to the longitudinal direction of the flat plate-like member. (3) Each of the above steps is carried out using a roll having an annular groove formed therein;
2. The method of manufacturing a strip of irregular cross section according to claim 1, wherein the manufacturing method is carried out using a processing device having a rectangular cross section and equipped with a roll or a fixed mold that protrudes into the annular groove.