JPH08281303A - Manufacture of angle steel - Google Patents

Abstract

PURPOSE: To provide a method for easily manufacturing large-sized angle steel without generating surface roughening and horizontal bending and having a good shape in the tip part. CONSTITUTION: This method for manufacturing an angle steel 10 by rolling and forming a rolling stock comprises an intermediate stage for working the rolling stock into a planer chevron shaped intermediate material 1 by hot-rolling, a tip forming stage for working into a preliminarily formed member by forming the tip part of the intermediate material into a chevron shape and the final working stage for forming the preliminarily formed member by one pass method using a two-direction rolling/forming roll device 3 which consists of an upper roll 31 and a lower roll 32. At least one of the upper roll 31 and lower roll 32 is movably back and forth supported to a hydraulic cylinder 72 through a roll chock 329 and, when working load over the set load is generated, the roll which is movable back and forth is retreated with the hydraulic cylinder 72.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing angle steel capable of easily manufacturing a large-sized product having no rough surface and a good shape.

[0002]

2. Description of the Related Art Angle steel is widely used as a structural material in buildings and the like. Generally, when an angle steel is manufactured using a rolled material that is easy to form, such as ordinary steel, it is rolled and formed using a rolling roll. However, as a rolling material, for example, a material having a lower deformability than ordinary steel such as austenitic stainless steel such as SUS304,
It has a large deformation resistance, and seizure easily occurs with the rolling roll during processing.

Therefore, conventionally, rough rolling is performed by using a plurality of sets of rolling rolls having a predetermined hole shape, and then the angle steel is manufactured into a desired shape. That is, as shown in FIGS.
18B to G, which are sequentially hot-rolled into the cross-sectional shapes 91 to 96 shown in FIGS. Then, finally, as shown in FIG. 18H, a right angle chevron 90 (FIG.
Mold into 9). That is, as shown in FIG. 19, an angle steel 90 obtained by the above-mentioned conventional method has two side portions including one side portion 902 and the other side portion 903, and an apex angle portion 901 where both side portions abut each other. ing. These moldings are usually 2
It is about 0 passes.

[0004]

[Problems to be Solved] However, the above conventional method has the following problems. That is, in the angle steel 90 obtained by the above conventional method, as shown in FIG.
The inner surface of the edge portion periphery 905 below 2, 903,
Rough skin 99 occurs on the outer surface.

Further, as shown in FIGS. 20 and 21, the tip portion of the angle steel 90 has a one-sided extension shape, that is, the tip portion 922 of the one side portion 902 is long and the tip portion 923 of the other side portion 903 is long. May have a short shape. Further, in the angle steel 90, bending may occur in the left and right directions.

In the above, the rough skin 99 is formed linearly in the longitudinal direction of the angle steel 90. Rough skin 9
The cause of occurrence of No. 9 is, as shown in FIG. 18 above, when the peripheral speed of the rolling rolls in each step is apex angle portion 901 and edge portion 905 in the process of sequentially forming the angle steel with a large number of rolling rolls. It depends on a big difference. That is, the peripheral speed is small in the molding portion of the apex angle portion 901, and the peripheral portion 9
The molded part of 05 is large. Therefore, the roughening occurs by performing molding with different peripheral speed differences for 20 passes as described above, and thereby a large number of roughenings occur at the edge portion 905.

In particular, the peripheral speed difference becomes larger as the shape of the angle steel is approached, and roughening occurs more frequently in the subsequent process. Further, the above-mentioned rough surface is relatively small in the small-angle chevron when compared with the rolling rolls having the same length. However, in the large-angle chevron steel with one long side, the peripheral speed difference is further increased, so that roughening of the skin occurs significantly.

Further, in the case of a large-sized chevron steel, in the rolling forming shown in FIG. 18, the rolling material cannot be rapidly deformed, so that many rolling rolls (for example, 25 passes) are required and the equipment is large. Shape.

Next, the cause of the shape defect of the tip is as follows.
As described above, it is considered that molding is performed by using many rolls, for example, 25 passes. That is, in a rolling process using a large number of rolls (FIG. 18) arranged continuously, the rolling material is formed while being constrained in its longitudinal direction. Therefore, tension is generated between the rolling stands. The elongation in the forming direction of the material due to this tension differs in the width direction, resulting in non-uniform elongation.

Further, in the case of a rolled material that has been partially processed, if the thickness of both sides of the rolled material varies, the thick side is strongly pressed. Therefore, the thick side portion is strongly worked and elongated, which promotes the uneven elongation. That is, the tip portion of the side portion on the thicker side of the rolled material is longer than the tip portion of the other side portion in the obtained angle steel.

Further, in this case, due to the difference in processing degree,
A difference also occurs in the processing hardness, and the processing hardness of the long side is higher than that of the other side. As a countermeasure for this, there is a method of adding a work hardening inhibiting element to the component of the material, but the cost is high and the effect is low.

In addition, when there is a difference in the workability of the left and right sides as described above, there is a difference in the length of both sides of the angle steel after working. Therefore, left and right bends occur. For example, when the right side has a high degree of processing, bending occurs in the left direction.

In view of the above problems of the prior art, the present invention does not cause skin roughness and left-right bending, and has a good tip shape.
It is an object of the present invention to provide a method for manufacturing angle steel, which enables large-sized angle steel to be easily manufactured.

[0014]

According to the present invention, a rolled material is roll-formed to produce an angle steel having two side portions, one side portion and the other side portion, and both side portions having an apex angle portion on the outer side. And an intermediate step of processing the above-mentioned rolling material into a flat mountain-shaped intermediate material having the apex angle portion by hot rolling, and forming the tip of the intermediate material into a mountain shape, and preforming Using a two-way forming roll device consisting of an upper roll and a lower roll
A final processing step of forming the preformed member by a one-pass method in which the preformed member is processed only once, and in the final processing step, at least one of the upper roll and the lower roll pivotally supports this. It is supported by a hydraulic cylinder via a roll chock so that it can move back and forth, and when a processing load greater than the set load occurs on any of the rolls, the hydraulic cylinder can set the roll that can move forward and backward below the set load. The method for manufacturing angle iron steel is characterized in that the above-mentioned forming is carried out by retreating to.

The most remarkable points in the present invention are an intermediate step of forming a rolling material into a flat mountain-shaped intermediate material having the apex angle portion, a tip forming step of processing the intermediate material into the preformed member, This is a final processing step of forming the angle steel by the one-pass method in which the preformed member is processed only once using the bidirectional forming roll device. Further, at least one of the upper roll and the lower roll in the two-way forming roll device is supported by a hydraulic cylinder so as to be capable of advancing and retreating with respect to one roll via a roll chock that supports the roll.

The bidirectional forming roll device comprises the upper roll for forming both side portions of the intermediate material into the chevron shape of the chevron steel to be obtained, and the lower roll for shaping the opposite inner surface side into the chevron shape. Have. The hydraulic cylinder arranged in the roll chock of the roll is connected to a separately provided hydraulic control device for controlling the pressing force of the hydraulic cylinder to be constant.

In carrying out the above manufacturing method,
First, in the above-mentioned intermediate material, the rolled material is processed into a flat mountain-shaped intermediate material by hot rolling. This intermediate material has an apex angle portion having substantially the same shape as the apex angle portion of the angle steel to be obtained. For example, the angle of the angle iron is 90 degrees or 1 degree.
If it is 20 degrees, the apex angle portion of the intermediate material is also approximately right angle or approximately 120 degrees. That is, in the intermediate member, first, the apex portion is formed, and two side portions extending from the apex portion to the left and right are formed into a flat mountain shape.

The flat mountain shape is composed of an apex portion and one side portion and another side portion extending from the apex portion to the left and right in substantially the same plane, or a straight or curved shape from the apex portion to the left and right. In addition, there is one having one side portion and the other side portion extending in the shape of an obtuse angle.

That is, the intermediate material has an apex portion having the same shape as the angle steel to be obtained, one side portion and another side portion extending from the apex portion to both sides, and the one side portion and the other side portion. There is one that is substantially flush with the sides and has a recess on the side opposite to the apex (FIG. 5). In this case, since the peripheral speed difference of the forming roll between the apex angle portion and the both side portions is extremely small, the rough skin does not occur. Further, since it has the above-mentioned concave portion, it can be easily formed into an angle steel.

The other intermediate material has an apex portion having the same shape as the angle steel to be obtained, and one side portion and the other side portion extending from the apex angle portion to both sides. Some of the other sides face an obtuse angle mountain shape (FIGS. 15 and 1).
6). In this case, since both sides form an obtuse angle, the final working process is easy.

Further, it is preferable that the tip portion of the preformed member has the same shape as the angle steel to be obtained. In this case, the initial processing in the final processing step is easier. Further, it is preferable that the final working step is performed by cold working or warm working. In this case, heat saving energy can be saved. The cold working means working without applying heat. Warm working refers to working at 300 to 700 ° C.

The final processing step is 800 ° C to 120 ° C.
It can also be carried out by hot working at 0 ° C. In this case, hot rolling is performed in the intermediate step, and the intermediate material in a high temperature state is continuously formed. Therefore, it is easy to process the preformed member and the final process.
It is also possible to save heat energy.

As the rolled material, a plastically deformable metal such as stainless steel, heat-resistant steel, structural steel or ordinary steel is used. Particularly in the case of stainless steel and heat-resistant steel, the deformability is low, so that the effect of the present invention is further exerted. As the angle steel obtained in the present invention, there is one in which one side and the other side are in contact with each other at a right angle.

In some of the angle steels, one side and the other side are in contact with each other at an obtuse angle. Further, the manufacturing method of the present invention can be applied to the production of either equilateral angle steel or unequal angle steel. Further, the manufacturing method of the present invention can be applied to any manufacturing in which the thickness of one side portion and the thickness of the other side portion are the same or different.

[0025]

In the present invention, the rolled material is formed in the order of the intermediate step, the tip forming step, and the final processing step to manufacture the angle steel. Then, in the intermediate step, first, a flat mountain-shaped intermediate material having a vertex is formed by hot rolling. Therefore, the machining shape in the intermediate process is
It is up to a flat mountain, and the peripheral speed difference of the forming roll forming the apex and both sides is very small compared to the case of the conventional example. Therefore, even if the shape is large, there is almost no occurrence of rough skin.

In addition, before the intermediate material is fed into the bidirectional forming roll device in the final processing step, its tip portion is formed into a mountain shape in the tip forming step. Therefore, the intermediate material can be easily inserted into the forming space of the two-way forming roll device, and the roll forming in the final processing step becomes easy.

In the final processing step, the upper roll presses the tops of the apexes and both sides of the intermediate material, and the lower roll presses the bottoms of both sides of the intermediate material. Here, both sides are formed into a desired angle steel shape. Then, in the final processing step,
It is molded using a one-pass method that processes only once. Therefore, the edge of the angle steel does not become rough.

Further, since the final processing step is the one-pass method, the tension between the stands does not cause non-uniform elongation as in the conventional case. Further, when a processing load exceeding the set load occurs on the upper roll and the lower roll, the roll that can move back and forth retracts, and the set load is maintained. Therefore, even if the thickness of both sides of the processed intermediate material varies, the thick portion is not strongly pressed.

Therefore, the tip of the obtained angle steel does not cause uneven elongation, maintains a good shape, and does not cause variations in working hardness. Therefore, it is not necessary to add a work hardening suppressing element.

Further, as described above, when a processing load larger than the set load is generated, the roll capable of advancing and retreating retracts, so that only one side is not strongly pressed down. Therefore, one side does not extend more than the other side.
Therefore, left and right bends do not occur in the obtained angle steel.

Therefore, according to the present invention, there is provided a method for manufacturing angle steel, which is free from rough skin and left-right bending, and can easily manufacture a large angle steel having a good tip shape. be able to.

[0032]

【Example】

Example 1 FIG. 1 shows a method for manufacturing angle steel according to an example of the present invention.
~ It demonstrates using FIG. As shown in FIG. 10, the angle steel to be manufactured in this example includes two side portions, one side portion 102 and the other side portion 103, and has a right-angled apex angle portion 101 in which both side portions abut each other. It is a right angle chevron steel 10.

In manufacturing the angle steel 10 described above,
As shown in FIGS. 3 and 4, an intermediate step of processing a rolled material into an intermediate material 1 and, as shown in FIG. 7, a tip portion 1 of the intermediate material 1.
7 is formed into a mountain shape and processed into a preforming member 170, and as shown in FIGS. 1, 8 and 9, the preforming member 17 is formed into a bidirectional forming roll device 3 by a one-pass method.
And a final processing step of rolling and forming an angle steel.

As shown in FIGS. 1, 8 and 9, the bidirectional forming roll device 3 comprises an upper roll 31 and a lower roll 32. The lower roll 32, as shown in FIG. 1, holds the roll shaft 324 of the roll chock 32.
It is supported by a hydraulic cylinder 72 so as to be capable of advancing and retracting via 9. The hydraulic cylinder 72 is connected to a hydraulic control device 702 as shown in FIG.

Further, as shown in FIG. 1, the upper roll 31
The roll chock 319 through the roll shaft 314.
Held in. And the roll chock 319
It is fixedly arranged in the upper housing 391 of the bidirectional forming roll device 3. Further, as shown in FIG. 1, the hydraulic cylinder 72 that supports the lower roll 32 so as to be capable of advancing and retracting is fixedly disposed in the lower housing 392 of the two-way forming roll device 3.

As shown in FIG. 2, the hydraulic control device 702 has a hydraulic pump 720 for pressurizing the hydraulic cylinder 72 through a check valve 721 and a relief valve 724 for maintaining a constant pressure. Also, the relief valve 7
24 and the hydraulic pump 720 are connected to the oil tank 723.

The details will be described below. First, in the intermediate step, as shown in FIGS.
A flat mountain-shaped intermediate material 1 having a side portion 12 and another side portion 13 on the left and right and an arc-shaped concave portion 14 on the opposite side (lower surface) of the apex angle portion 11 is formed by hot rolling. The one side portion 12 and the other side portion 13 have the same size and are in the same plane. In the hot rolling process, as shown in FIG. 3, upper rolls 211 to 219 and lower rolls 221 to 221 are processed.
229 pairs of rolling rolls 2 are used.

For example, as shown in FIG. 4, the upper roll 2 for forming the final shape of the intermediate step, that is, the final shape of the intermediate material.
Reference numeral 19 denotes an apex angle portion 11 on the upper surface of the intermediate member 1 and both side portions 1
The upper surfaces of 2 and 13 are roll-formed. On the other hand, the lower roll 229
Is the above-mentioned arcuate recess 14 and both side portions 1 on the lower surface of the intermediate member 1.
The lower surfaces of 2 and 13 are molded. The rolled material is a billet having a quadrangular cross section, which is sequentially formed into the intermediate material 1 by the upper and lower rolling rolls.

Next, in the tip forming step, as shown in FIG. 7, the tip portion 17 of the intermediate material 1 is formed into a mountain shape and processed into a preforming member 170. This processing is performed by pressing. Next, in the final processing step, as shown in FIG. 1, FIG. 2, FIG. 8 and FIG. 9, the bidirectional forming roll device 3 including the upper roll 31 and the lower roll 32 is used. Then, for this device 3, the preformed member 1
The tip portion of 70 is inserted, and the intermediate material 1 is sequentially roll-formed on the desired angle steel 10 by the one-pass method.

As shown in FIGS. 1, 8 and 9, the upper roll 31 has an upper surface of the apex angle portion 11 and a processing surface 311 for forming the upper surfaces of both side portions 12, 13 at right angles. Also,
The lower roll 32 includes a lower surface of the apex corner portion 11 and both side portions 12, 13
Has a processing surface 321 for forming the lower surface of the above into a rectangular shape.

As a result, as shown in FIGS. 10 and 11, the angle α formed by both side portions 102 and 103 is
Angle steel 10 is manufactured. In the above manufacturing method, as shown in FIG.
It is also possible to produce an obtuse angle iron 18 with 3 having an angle β. In this case, the intermediate material having the apex angle portion 181 having an obtuse angle β is hot-rolled in the intermediate step.

Next, the function and effect of this example will be described. In this example, a flat mountain-shaped intermediate material is hot-rolled in the intermediate step. Therefore, hot rolling may be performed to a flat mountain shape. Therefore, the peripheral speed difference in the forming roll is very small compared to the conventional example. Therefore, there is almost no occurrence of rough skin.

Further, since the tip portion 17 of the intermediate material 1 is formed into a mountain shape prior to the final processing step, the intermediate material 4 can be easily inserted into the bidirectional forming roll device 3 in the final processing step. . Therefore, the processing at the beginning of molding can be smoothly performed.

Further, in the final processing step, the bidirectional forming roll device 3 is used to press the apex angle portion and both side portions of the intermediate material by the upper roll and the lower roll, and the desired shape is obtained by the one-pass method. It is rolled and formed into angle steel. Therefore, the edge of the angle steel 10 does not become rough.

Further, since the final processing step is performed by the one-pass method, the tension between the stands does not cause non-uniform elongation as in the conventional case. Further, when a processing load exceeding the set load is generated in the upper roll 31 and the lower roll 32, the operation of the hydraulic cylinder 72 causes
Lower roll 3 which is arranged to be able to move forward and backward with respect to upper roll 31
2 retracts and the set load is maintained.

Therefore, even if the thickness of both sides of the processed intermediate material 1 varies, the thick portion is not strongly pressed. Therefore, the tip of the obtained angle steel does not cause uneven elongation, maintains a good shape, and does not cause variations in work hardness. Therefore, it is not necessary to add a work hardening suppressing element.

Further, as described above, when a processing load larger than the set load is generated, the lower roll 32 retracts as described above, so that only one side portion is not strongly pressed. Therefore, one side does not extend more than the other side. Therefore, left and right bends do not occur in the obtained angle steel.

Therefore, according to the present example, it is possible to easily manufacture a large-angle chevron steel which does not cause rough skin and left-right bending and has a good tip shape.

Example 2 As shown in FIGS. 13 and 14, this example shows a method of manufacturing angle-angled angle steel with unequal sides (FIG. 14). In the present example, in the intermediate step, as shown in FIG. 13, the intermediate material 4 including the apex angle portion 41, the one side portion 42 and the other side portion 43 is formed by hot rolling. The lower surface of the apex portion 41 has an arc-shaped recess 410. Further, the length of the other side portion 43 is shorter than that of the one side portion 42.

Otherwise, the intermediate step, the tip forming step, and the final working step are performed in the same manner as in Example 1 to manufacture the unequal-angled angle angle steel 40 shown in FIG. Also in this example, the same effect as that of the first embodiment can be obtained.

Example 3 As shown in FIGS. 15 and 16, this example shows a method for manufacturing angle steel using an intermediate material 16 or 45 having a shape different from that of Example 1. The intermediate member 16 shown in FIG. 15 includes a vertex portion 161, a side portion 162, and another side portion 163. The apex portion 161 has a right angle shape. One side 162, the other side 16
3 extend from the apex angle portion 161 to the left and right, forming obtuse angles with each other. The both side portions 162, 163 are slightly curved and have the same length.

On the other hand, the intermediate member 45 shown in FIG. 16 is made up of a vertex portion 451, a curved one side portion 452 and another side portion 453. The apex portion 451 has a right-angled shape, and both side portions 4
52 and 453 are obtuse-angled. The other side portion 453 is
It is shorter than the side portion 452. Others are the same as in the first embodiment. In this example, the equilateral angle steel (FIG. 10) is obtained when the intermediate material 16 is used, and the unequal angle steel (FIG. 14) is obtained when the intermediate material 45 is used. Also in this example, the same effect as that of the first embodiment can be obtained.

Example 4 In this example, a specific example of the method for manufacturing the angle steel shown in Example 1 will be described. In this example, the rolled material was stainless steel SUS304. This rolled material has a cross section of 3
The billet is 20 mm × 185 mm. This rolling material was hot-rolled for 10 passes using a rolling roll to form the intermediate material 1 shown in FIGS. 5 and 6.

As shown in FIGS. 6 and 17, the length L of both side portions 12 and 13 of the intermediate member 1 is 150 mm, the thicknesses H of H1 and H2 are 15.0 mm, and H3 and H4 are 15.
5 mm, the height T of the apex portion 11 was 30 mm, and the length K of the apex portion was 40 mm. The hot rolling process in the intermediate step was performed at about 900 ° C. Next, in the tip forming step, the tip portion was formed into a substantially right angle shape by a press machine to prepare a preformed member.

Next, in the bidirectional forming roll device,
The upper roll and the lower roll were rotated at a rotation speed of 5.0 rpm to form an intermediate material by cold working. As a result, the thickness H1, H2 of the one side portion 102 is 15.0 mm, the thickness H3, H4 of the other side portion 103 is 15.5 mm, and the apex angle portion 1 is
The length from the apex of 01 to the end faces of the side portions 12 and 13 is 1
A right angle chevron steel of 50 mm was obtained. Almost no rough skin was observed at the edge of the angle steel. In addition, the thickness of the side portion from the above was almost unchanged compared to the case of the intermediate material.

Further, as shown in FIG. 17, in the conventional case, the shape of the tip of the angle steel becomes defective due to the difference in the thickness of both sides of the intermediate material 1 (solid line position A1). The tip lengths of both sides were almost the same (dotted line position A2), and a good tip shape was obtained. In addition, in the angle steel of this example, no left-right bending occurred.

Example 5 In this example, the final processing step using a bidirectional forming roll device was carried out by hot working at about 950 ° C. This hot working is an intermediate material 1 formed by hot rolling.
Was transferred to the tip forming step while still hot, and then to the final processing step, which was performed by continuous processing. Others are the same as in the fourth embodiment. Also in this example, the same effect as in Example 4 could be obtained.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a configuration of a bidirectional forming roll device according to a first embodiment.

FIG. 2 is an explanatory diagram of a hydraulic cylinder and a hydraulic control device according to the first embodiment.

FIG. 3 is an explanatory diagram of an intermediate process in Example 1.

FIG. 4 is an explanatory view of a final forming roll for forming an intermediate material in Example 1.

FIG. 5 is a perspective view of an intermediate material according to the first embodiment.

FIG. 6 is an explanatory view of the dimensions of the intermediate material according to the first embodiment.

FIG. 7 is a perspective view of a preformed member according to the first embodiment.

FIG. 8 is a perspective view of a final processing step in the first embodiment.

FIG. 9 is a front view of the bidirectional forming roll device according to the first embodiment.

FIG. 10 is a perspective view of angle steel in Example 1.

11 is an explanatory view of angle steel in Example 1. FIG.

FIG. 12 is an explanatory diagram of another angle steel in Example 1.

FIG. 13 is a perspective view of an intermediate material according to the second embodiment.

FIG. 14 is a front view of unequal angle steel in Example 2.

FIG. 15 is a front view of an intermediate material according to the third embodiment.

FIG. 16 is a front view of another intermediate material according to the third embodiment.

FIG. 17 is an explanatory diagram of the relationship between the thickness of the intermediate material and the tip shape of the angle steel in Example 4.

FIG. 18 is an explanatory view of a manufacturing process of a conventional angle steel.

FIG. 19 is an explanatory view showing a problem of the angle steel of the conventional example.

FIG. 20 is a perspective view of another conventional angle iron.

FIG. 21 is a plan view of another conventional angle steel.

[Explanation of symbols]

 1. ． ． Intermediate material, 10. ． ． Angle steel, 11, 101. ． ． Apex, 12, 102. ． ． One side, 13, 103. ． ． Other side, 17. ． ． Tip, 19. ． ． Rolling material, 31. ． ． Upper roll, 32. ． ． Lower roll, 319, 329. ． ． Roll chock, 72. ． ． Hydraulic cylinder, 2. ． ． Rolling rolls, 3. ． ． Bi-directional forming roll device, 40. ． ． Unequal angle steel,

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Naoto Suzuki No. 1 Wano Wari, Arao-cho, Tokai City, Aichi Prefecture Aichi Steel Co., Ltd.

Claims (6)

[Claims] 1. A method for producing a mountain iron bar having two side portions, one side portion and the other side portion, and having an apex angle portion on the outer side in which both side portions contact each other, by rolling forming a rolled material. An intermediate step of processing the rolled material into a flat mountain-shaped intermediate material having the apex angle portion by hot rolling, and a tip of forming the tip portion of the intermediate material into a mountain shape and processing it into a preformed member A forming step and a final processing step of forming the preforming member by a one-pass method in which the preforming member is processed only once by using a bidirectional forming roll device including an upper roll and a lower roll, and in the final processing step, At least one of the upper roll and the lower roll is supported by a hydraulic cylinder so as to be able to move back and forth through a roll chock that pivotally supports the upper roll and the lower roll. When produced, the angle cylinder is made to retreat by the hydraulic cylinder so that the roll can be moved back and forth so that the load is equal to or less than a set load, and the forming is performed. 2. The intermediate member according to claim 1, wherein the intermediate material has an apex portion having the same shape as the angle steel to be obtained, and one side portion and another side portion extending from the apex portion to both sides. A method for manufacturing angle steel, wherein one side portion and the other side portion are substantially in the same plane, and a concave portion is provided on the side opposite to the apex angle portion. 3. The intermediate material according to claim 1, wherein the intermediate material has an apex portion having the same shape as the angle steel to be obtained, and one side portion and another side portion extending from the apex portion to both sides. A method for manufacturing angle steel, wherein one side and the other side face each other in an obtuse angle mountain shape. 4. The method according to claim 1, wherein
A method for manufacturing an angle steel, wherein a tip portion of the preformed member has substantially the same shape as the angle steel to be obtained. 5. The method according to any one of claims 1 to 4,
A method for manufacturing angle steel, wherein the final working step is performed by cold working or warm working. 6. The method according to any one of claims 1 to 4,
A method for manufacturing an angle steel, wherein the final working step is performed by hot working.