JP4376602B2 - Metal material processing method and metal processed product - Google Patents

Description

  In the present invention, a shape steel such as a channel, an angle, and a hat steel having a beautiful right-angled bending portion (hereinafter referred to as “pin angle”) in at least one place is provided with beautiful skin for building materials and structures. The present invention relates to a method for processing a metal material to be processed, and a metal processed product having a sharp pin angle.

  The methods of manufacturing shaped steel such as channels and angles are roughly divided into two methods: hot rolling and cold rolling, but there are other methods that combine hot rolling and cold rolling. A method of performing cold rolling by heating or a method of performing cold rolling after cold forming (forming) is known.

  In the hot rolling method, since the deformation resistance of the material is small, the inner and outer corner curvatures of the right angle bend can be obtained relatively easily, but metal melting and pickling facilities are required. In addition, since the skin of the finished surface is rough, surface polishing is indispensable when it is used in a part that requires design properties such as an outer wall for building materials and automobile parts. For this reason, for example, in the method of Patent Document 1, it may be necessary to incorporate a surface polishing step into the intermediate step. However, the surface polishing process is very time-consuming, expensive, and problematic in terms of the working environment.

  Patent Document 2 discloses a method of bending a belt-like member having a convex portion at the center of which work hardening has not occurred into an L shape by cold forming, and further rolling an inner and outer apex angle portion to a predetermined R by a horizontal roll and a vertical roll. Is disclosed. However, in the method of Patent Document 2, in addition to the need for an extra process for manufacturing a strip-shaped member having a convex part at the center, which is not subjected to work hardening, before the cold forming process, work hardening is performed. Although it does not occur, it is obvious that it is difficult to bend a belt-like member having a thickness thicker than both ends as compared with a normal uniform thickness bend. In addition, it is considered that wrinkles are generated at the inner corners when the bending is completed, and when the generated wrinkles are crushed with horizontal and vertical rolls, there remains a problem of defect generation due to the crushing of the wrinkles at the inner corners.

  In the method disclosed in Patent Document 3, since the crushing force in the length direction of the material escapes, it is considered that the two-dimensional projection length Lp of the outer corner after bending does not become as small as desired.

In Patent Document 4, after forming the stainless steel strip by cold forming, the side near the corner of the side A having a large rigidity is translated as it is by crushing the side of the angle from above and below, and the curvature R of the inside and outside is When the entire side B including the portion is deformed in the direction of the end a1 of the side A, the portion where the curvature R is in contact with the straight line is crushed. A method of obtaining an angle having an outer angle substantially perpendicular by reducing the arc length of the outer corner portion formed by cold forming by performing this operation on each side is disclosed.
JP-A-4-059101 JP-A-6-246302 JP-A-6-246301 Japanese Patent Laid-Open No. 10-005909

  However, according to any of the methods of Patent Documents 1 to 4, in the product by bending, the size of the curvature R of the outer corner (the two-dimensional projection length) is not small and sharp, and usually stays above the plate thickness. Many. Moreover, although the channel of a hot rolling shaping | molding like patent document 1 becomes comparatively small in the curvature of an outer corner part, there exists a problem that the skin of a product surface becomes rough.

  As shown in FIG. 8A, the conventional channel 20C has a large outer corner radius of curvature R1 of the corner c1. As shown in FIG. 9, for example, the channels 20C having the corners c1 having the large outer corner radius of curvature R1 are arranged in parallel, and the adjacent channels 20C and 20C are welded by the arc welder 130, as shown in FIG. When the outer wall is formed, since the corner portion c1 has a large curvature R, the welding arc 131 does not sufficiently enter the mutual contact portion 132 of the two channels, resulting in poor welding.

  In addition, general structural lightweight steel (JIS G 3350) such as channel, angle, and hat steel is attached to the outer wall of a building and is often used decoratively as an exterior panel. When R is attached, the appearance of the web 20a surface and the corner portion c1 look quite different, and it is not preferred by users even from an aesthetic point of view. The same problem occurs when the surface of the flange 20b is exposed as an outer wall.

  The same problem occurs with respect to the outer corner portion c2 of the conventional angle 300 shown in FIG. Further, the same problem occurs in the outer corner portions c3 and c4 of the conventional hat steel 400 shown in FIG.

  The present invention has been made in order to solve the above-mentioned problems, and is a method for processing a metal material capable of reducing the two-dimensional projection length Lp of an outer corner portion of a shape steel such as a channel, an angle, and a hat steel, and two outer corner portions. An object of the present invention is to provide a metal processed product having a small dimensional projection length Lp and a beautiful skin.

  In order to solve the above problems and achieve the object, the present invention uses the following means.

(1) A method for processing a metal material according to the present invention includes a pre-forming step of forming a long metal material into a pre-formed member having a predetermined cross-sectional shape having at least one right-angle bend by cold-forming forming a long metal material, A first rolling step of bulging the outer side portions near both sides of the corner portion together with the corner portions of the preformed member in the warm or warm state to form a primary molded member having a bulged portion; The bulging portion is pushed inwardly toward the inside of the corner, and the two-dimensional projection length of the outer corner is Lp, the thickness of the side is t, and the top thickness from the inner corner to the outer corner is T. The second rolling step of forming a secondary molded member having an outer corner portion that simultaneously satisfies the relationship of 0.5 mm ≦ Lp ≦ 0.3 t and t <T .

(2) In the metal material processing method of the present invention, in the first rolling step, the length of the outer side portion bulged outward is 1/2 or less of the length of each side on both sides of the corner portion. The method according to (1) above .

(3) In the metal material processing method of the present invention, in the first rolling step, the curvature radius Re of the roll edge of the vertical roll contacting the inner corner of the preformed member is set to the curvature of the inner corner of the preformed member. 3. The method according to any one of (1) and (2), wherein the radius Ri is smaller than the radius Ri.

(4) method for processing a metallic material according to the present invention, further, after the second rolling step, said having a third rolling step of the cross-sectional shape of the secondary molded member is corrected to a desired shape The method according to any one of (1) to (3) .

(5) The metal workpiece of the present invention is molded using any one of the methods (1) to (4), the two-dimensional projection length Lp of the outer corner is 0.5 mm or more, It is 0.3 times or less of the thickness t.

  The present invention can be suitably used for shape steels having various cross-sectional shapes including at least one right-angled bending portion, in particular, lightweight steel shapes for general structures such as channels, angles, and hat steels.

  The present invention can be suitably used not only for ferrous metal materials such as carbon steel (soft steel) and stainless steel but also for non-ferrous metal materials such as titanium.

  Moreover, this invention is used suitably in the range whose thickness t is 3-6 mm, and is used most suitably especially in the range whose thickness t is 3-4.5 mm. Even if the thickness t is less than 3 mm, it is presumed that the same effect can be obtained by using the present invention.

  In the present specification, the two-dimensional projection length Lp at the outer corner is defined to mean the X-axis length or Y-axis length of the mapping projected onto the XY plane.

  According to the present invention, the outer corner radius of curvature of the metal workpiece having at least one right angle bending portion can be reduced, and particularly the radius of curvature of both outer corner portions (edges) can be reduced in the channel. When used for building outer walls and elevator hall frames, it has an excellent appearance with a uniform reflection surface, and it has a sharp shape that is easy to weld on the construction surface.

  In addition, since the present invention is rolled cold or warm, surface roughness such as hot rolling does not occur, and a beautiful metal processed product having a metallic luster on the surface can be obtained.

  The applicant of the present application has proposed a method of reducing the arc length of the outer corner portion R of the angle in Patent Document 4 corresponding to the prior application. However, in the method of Patent Document 4, wrinkles are generated on the surface of the angle inner corner when the side is crushed. Although the wrinkles at the inner corners do not substantially affect the strength, there is an inconvenience that they are not so preferable in appearance because they are easily mistaken for cracks by the user. In the method of Patent Document 4, the arc length of the outer corner portion R can be remarkably reduced as compared with a normal cold forming product, but the outer corner portion R in the original cold forming remains in an almost intact shape. There is a problem that the angle has an appearance that gives an impression as if it has a chamfered outer corner. Furthermore, in the method of Patent Document 4, when the outer corner portion R is formed, the inner corner portion R also becomes smaller, which causes a problem that the thickness of the corner portion is reduced.

  Therefore, as a result of intensive research on the channel manufacturing technique in association with the angle, the present inventors similarly generate the above-mentioned problem that occurs when the outer corner portion R of the angle in the method of Patent Document 4 is reduced. In order to solve this problem, repeated trial and error in which the forming channel formed by cold roll forming is cold or warm rolled by a four-way rolling machine in which the shape of the vertical and horizontal roll surfaces is changed, is repeated. The present invention has been completed.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a schematic view showing an example of a production line used for carrying out the method of the present invention. In the production line 1, an uncoiler 3, a cold roll forming device 4, an oil draining device 5, a heating device 6, a multi-stage rolling mill 8 for straightening, a straightening machine 9, a cutting machine 10, and a conveyance table 11 are arranged in order from the upstream side. Yes. In this example, a hot-rolled stainless steel strip having a thickness of 3 mm was used as the metal material 2, and a channel of a predetermined size was manufactured by the manufacturing line 1. The production was carried out as follows.

  First, the hot rolled stainless steel strip 2 is mounted on the uncoiler 3. The stainless steel strip 2 as a raw material is attached to the uncoiler 3 after being subjected to a surface polishing step after hot rolling and cut in the longitudinal direction with a predetermined width.

  The stainless steel strip 2 is fed from the uncoiler 3 in the direction of the arrow in the figure, relayed by the coil relay device, and enters the cold roll forming device 4 via the entry side guide. In the cold roll forming apparatus 4, the stainless steel strip 2 is gradually bent cold or warm by multi-stage forming rolls, and is formed into the shape of the preformed member 20 having a cross-sectional shape shown in FIG.

  The steps so far are substantially the same as the steps described in Patent Document 3 above. However, the preforming process of the present embodiment is different from the process of the conventional method in that the curvature of the corner portion c1 of the preformed member 20 is larger than that of the conventional product manufactured by the method described in Patent Document 3. Yes. That is, in the conventional channel 20C shown in FIG. 8A, the inner corner radius R2 of the corner c1 is equal to the plate thickness t (R2 = t), and the outer corner radius R1 is twice the plate thickness t (R1 = 2t). In contrast, in the preformed member 20 shown in FIG. 6A, the inner corner radius of curvature Ri of the corner portion c1 exceeds the thickness t (Ri> t), and the outer angle radius of curvature Ro is 2 of the thickness t. Cold roll forming is performed so as to exceed twice (Ro> 2t). Moreover, in the preforming member 20, the top thickness T from the inner corner apex to the outer corner apex is made thicker than the conventional channel 20C. Furthermore, the two-dimensional projection length Lp of the outer corner is increased so as to exceed twice the plate thickness t (Lp> 2t).

  Usually, in cold roll forming, processing oil (water-soluble processing oil) is used for the purpose of reducing friction between the roll and the stainless steel strip 2 and cooling the stainless steel strip 2 that generates heat. In order to heat the steel strip 2, the oil draining device 5 performs oil draining when the cold roll forming is completed.

  The preformed member 20 that has been drained is locally heated by the next heating device 6 to at least the corner c1 from the outside to a temperature of 200 ° C. or less. In the present embodiment, a high-frequency induction heater is used as the heating device 6, but the present invention is not limited to this, and heating may be performed using other means such as a hot air generator. The purpose of this local heating is to make it easy to work warmly without applying excessive load to the four-direction rolling forming roll of the multi-stage rolling mill 8 for the next step, but it is particularly cold without heating. It is also possible to process. That is, the processing method of the present invention can be carried out cold or warm.

  When the preformed member 20 having locally heated the corner c1 enters the multi-stage rolling mill 8 for squaring, the first-stage four-way rolling mill 81A, the second-stage four-way rolling mill 82, and the third-stage four-rolling mill 8 While continuously passing through the directional rolling mill 83, the cross-sectional shape changes from (a) to (b), (b) to (c), and (c) to (d) in FIG. That is, in the first-stage rolling mill 81A, the preformed member 20 (FIG. 6A) is molded into the primary molded member 201 (FIG. 6B), and in the second-stage rolling mill 82, the primary molded member 201 ( 6 (b)) is formed into a secondary forming member 202 (FIG. 6 (c)). In the third-stage rolling mill 83, the secondary forming member 202 (FIG. 6 (c)) is finished with a finished forming member 203 (FIG. 6). 6 (d)).

  Next, with reference to FIG. 2, FIG. 3, FIG. 6, the first-stage four-way rolling mill and its operation will be described in detail.

  As shown in FIG. 2, the first four-way rolling mill 81 </ b> A includes vertical rolls 811 and 812 and horizontal rolls 813 and 814 that are disposed so as to surround a pass line through which a workpiece passes from above, below, left and right. Each axis of the vertical rolls 811 and 812 is connected to a drive shaft (not shown). The upper vertical roll 811 is driven to rotate about the x1 axis parallel to the reference horizontal line, and the lower vertical roll 812 is driven to rotate about the x2 axis parallel to the reference horizontal line. The left and right horizontal rolls 813 and 814 are free rolls supported to freely rotate, and are driven to rotate about the y1 axis and the y2 axis parallel to the vertical line as the work advances.

  FIG. 3 is an enlarged schematic cross-sectional view showing a part of the first-stage four-direction rolling mill 81A. Since the left and right lateral rolls 813 and 814 have substantially the same configuration, only the right lateral roll 814 is shown in the figure, and the left lateral roll 813 is omitted.

  The upper vertical roll 811 is a drive roll having a large diameter portion and a small diameter portion. During rolling, the roll surface 811a of the large diameter portion is in contact with the web inner surface a1 of the workpiece, and the roll side surface 811b of the large diameter portion is in contact with the flange inner surface b1 of the workpiece. The roll edge of the large diameter portion has a radius of curvature Re smaller than the radius of curvature Ri of the inner corner portion of the workpiece (pre-formed member 20 in FIG. 6A) (Re <Ri). This upper vertical roll 811 pushes out the workpiece | work corner | angular part c1 shown to Fig.6 (a) by the roll edge at the time of rolling, and the excess meat inside the vicinity to the outer side. A stepped portion 811 c is formed between the large diameter portion and the small diameter portion of the roll 811. The stepped portion 811c prevents the flange 20b from extending upward while defining the flange end surface a3 of the workpiece during rolling, and adjusts the cross section of the workpiece to a predetermined shape.

  The lower vertical roll 812 is a drive roll having a roll surface composed of a flat portion 812a, a tapered portion 812b, and a concave portion 812c. A gap S3 for forming a bulge is formed between the recess 812c and the web outer surface a2 of the workpiece. On the entry side of the lower vertical roll 812, only the flat portion 812a is in contact with the web outer surface a2 of the workpiece, and the tapered portion 812b and the recess portion 812c are in a non-contact state away from the workpiece 20, but on the exit side, the upper vertical roll 811 The material extruded in this manner comes into contact with the tapered portion 812b and the concave portion 812c, respectively, and as a result, the corner portion c1 and the web surface a2 in the vicinity thereof bulge outward.

  Since the right and left horizontal rolls 813 and 814 have the same configuration, the right horizontal roll 814 will be described here as a representative. The transverse roll 814 is a freely rotatable roll having a large diameter portion and a small diameter portion. The roll surface of the large-diameter portion of the roll 814 includes a flat portion 814a, a tapered portion 814b, and a concave portion 814c in this order from the upper side, and is not in contact with the workpiece 20 (substantially non-contact). A stepped portion 814d is formed between the large diameter portion and the small diameter portion of the horizontal roll 814. The stepped portion 814d is configured not to interfere with the side surfaces of the upper and lower vertical rolls 811 and 812.

  A gap S1 is formed between the flat portion 814a of the large-diameter portion roll surface and the flange outer surface b2 of the workpiece. The gap S1 is for preventing burrs generated between the vertical and horizontal rolls 811 and 814. The tapered portion 814b and the recessed portion 814c are further away from the flange outer surface b2 of the workpiece. A gap S2 for forming a bulge is formed between the recess 814c and the flange outer surface b2 of the workpiece. As described above, the flat portion 814a, the tapered portion 814b, and the concave portion 814c are all in the non-contact state on the entry side of the horizontal roll 814, but the material extruded outward by the upper vertical roll 811 is tapered on the exit side. As a result, the corner portion c1 and the flange surface b2 in the vicinity thereof bulge outward.

  Next, with reference to FIG. 4 to FIG. 6, the second and third four-way rolling mills of the multi-stage rolling mill for squaring and the operation thereof will be described in detail.

  As shown in FIG. 4, the second-stage four-direction rolling mill 82 includes vertical rolls 821 and 822 and horizontal rolls 823 and 824 that are disposed so as to surround a pass line through which a workpiece passes from above, below, left, and right. Each axis of the vertical rolls 821 and 822 is connected to a drive shaft (not shown). The upper vertical roll 821 is rotationally driven about the x1 axis parallel to the reference horizontal line, and the lower vertical roll 822 is rotationally driven about the x2 axis parallel to the reference horizontal line. The left and right horizontal rolls 823 and 824 are free rolls that are freely supported to rotate, and are driven to rotate about the y1 axis and the y2 axis parallel to the vertical line as the work advances.

  FIG. 5 is an enlarged schematic cross-sectional view showing a part of the second-stage four-way rolling mill 82. Since the left and right lateral rolls 823 and 824 have substantially the same configuration, only the right lateral roll 824 is shown in the figure, and the left lateral roll 823 is omitted.

  The upper vertical roll 821 is a drive roll having a large diameter portion and a small diameter portion. During rolling, the roll surface 821a of the large diameter portion is in contact with the web inner surface a1 of the workpiece, and the roll side surface 821b of the large diameter portion is in contact with the flange inner surface b1 of the workpiece. A stepped portion 821 c is formed between the large diameter portion and the small diameter portion of the roll 821. The stepped portion 821c prevents the flange 20b from extending upward while defining the flange end surface a3 of the workpiece during rolling, and adjusts the cross section of the workpiece to a predetermined shape.

  The lower vertical roll 822 is a drive roll having a roll surface composed of only the flat portion 822a. The upper and lower vertical rolls 821 and 822 reduce the entire length of the workpiece web 20a. As a result, the material of the corner c1 bulging outward and the web surface a2 in the vicinity thereof is pushed back inward.

  Since the right and left horizontal rolls 823 and 824 have the same configuration, the right horizontal roll 824 will be described as a representative here. The transverse roll 824 is a freely rotatable roll having a large diameter portion and a small diameter portion. In addition, the space | interval of the right and left horizontal rolls 823 and 824 is set so that the roll surface 824a contacts the flange 20b opened outward in the flare shape shown in FIG. 6B. Further, a stepped portion 824 b is formed between the large diameter portion and the small diameter portion of the horizontal roll 824. The stepped portion 824b is configured not to interfere with the side surfaces of the upper and lower vertical rolls 821 and 822.

  While restricting displacement in the width direction of the workpiece by the horizontal roll 824, the entire flange length of the workpiece is reduced by the upper vertical roll 821. As a result, the material of the corner c1 bulging outward and the flange 20b in the vicinity thereof is pushed back inward, and together with the material pushed back from the web 20a by the lower vertical roll 822, the material is brought into the corner c1 of the workpiece. Ingredients (meat) gather together. As a result, as shown in FIG. 6C, the corner c1 becomes sharp and the secondary molded member 202 has a small two-dimensional projection length Lp at the outer corner. The secondary molded member 202 has a beautiful surface and an excellent appearance.

  4 and 5, the third-stage rolling mill 83 is shown in the same manner as the second-stage rolling mill 82, but the horizontal rolls of both are actually different. The roll is an overbend roll for springback correction. That is, the roll surface 824a is flattened in the horizontal roll of the second-stage rolling mill 82, but in the horizontal roll of the third-stage rolling mill 83, the upper surface of the roll surface is a tapered surface slightly inclined inward. . The inclination angle of the taper roll surface is about several degrees, the flange 20b of the secondary forming member 202 shown in FIG. 6 (c) is slightly bent inward to correct the spring back, and finish forming shown in FIG. 6 (d). The member 203 is used.

  As described above, a channel (finish forming member 203) having a sharp pin angle in which the two-dimensional projection length Lp of the outer corner portion is 0.3 times or less of the plate thickness t is obtained. Next, twisting, warping, and lateral bending (camber) of the channel 203 are corrected by the correction machine 9, and the channel 203 is made linear. Subsequently, this is sent to the cutting machine 10, cut into a predetermined length, and then carried out by the carry-out table 11.

  All of the above molding processes are performed in a series of steps as shown in the figure. In addition, the workability is better as the corner c1 of the channel is truly a right angle in actual work such as welding work. However, when the channel is handled by hand, there is a possibility that the worker will cut the hand as the angle is truly right, and an object having a slight R portion is easier to handle from the viewpoint of safety. Therefore, in the present invention, it is desirable that the minimum value of the two-dimensional projection length Lp at the outer corner is 0.5 mm.

Example 1
A material 2 (thickness 3 mm × width 132 to 137 mm) obtained by polishing a surface of a hot rolled stainless steel strip (JIS G 4306, SUS304-HS, t3.0 mm) as a test material of Example 1 and cutting it in a longitudinal direction with a slitter. X Length 5-6 m) was prepared.

  By passing the stainless steel strip material 2 through a cold roll forming device 4, a preformed channel 20 shown in FIG. 6 (a) was obtained. The preformed channel 20 had a thickness t1 of 3 mm, a flange length B1 of 27 to 28 mm, a web length H1 of 62 mm, and an outer corner radius of curvature Ro of 5 to 6 mm.

  After removing the water-soluble processing oil from the pre-formed channel 20 with a rubber wiper (oil removal device 5), the material temperature (the temperature at the channel corner c1) is 170 to 190 ° C. with the high frequency induction heating device (heating device 6). It was heated locally so that it was continuously passed through four-direction rolling mills 81A, 82, 83 of the first, second, and third stages.

  As the multi-stage rolling mill for cornering of this embodiment, the diameter D1 of the large diameter portion of the upper vertical roll is about 230 to 250 mm, the diameter D2 of the small diameter portion of the upper vertical roll is about 180 to 200 mm, and the stepped portion of the upper vertical roll The length of the roll is about 8 to 10 mm, the radius of curvature Re of the roll edge of the upper vertical roll is in the range of 0.5 to 1.0 mm, the diameter of the flat part of the lower vertical roll is about 210 to 230 mm, A three-stage four-way rolling mill is used in which the diameter D3 of the diameter part is about 60 to 70 mm, the diameter D4 of the small diameter part of the horizontal roll is about 40 to 50 mm, and the length of the stepped part of the horizontal roll is about 5 to 7 mm. It was.

  In this embodiment, the length L1 of the flat portion of the transverse roll is about 10 to 15 mm, the length L2 of the tapered portion is 8 to 10 mm, and the inclination angle θ1 of the tapered portion of the transverse roll is several degrees with respect to the vertical line. The concave portion length L3 is 4 to 6 mm, the gap S1 between the workpiece before rolling and the flat portion of the transverse roll is 0.4 to 0.6 mm, and the gap S2 between the workpiece before rolling and the concave portion of the transverse roll is It was set to 0.7 to 0.9 mm.

  Further, in this embodiment, the length L5 of the taper portion of the lower vertical roll is 8 to 10 mm, the inclination angle θ2 of the taper portion of the lower vertical roll is inclined by several degrees with respect to the reference horizontal line, and the length of the concave portion of the lower vertical roll is The thickness L4 was 10 to 12 mm, and the gap S3 between the workpiece before rolling and the concave portion of the lower vertical roll was 0.5 to 0.7 mm.

  The setting positions of the vertical and horizontal rolls of the first, second, and third stage four-direction rolling mills 81A, 82, and 83 are the size of the preforming channel 20 (thickness 3 mm, flange length 27 to 28 mm). The web length was adjusted according to the roll dimension and roll interval determined in advance by 62 mm).

  That is, in the first-stage four-direction rolling mill 81A, if the interval between the large diameter portion of the upper vertical roll 811 and the lower vertical roll 812 is set to 3 mm, the stepped portion 811c of the upper vertical roll and the lower vertical roll 812 The upper vertical roll 811 is manufactured so that the interval is 27 to 28 mm. However, the stepped portion 811c was not in contact with the flange end surface a3 of the pre-formed channel 20, and the vertical rolls 811 and 812 were set so as to be positioned at a distance of about 0.5 mm to 1 mm. On the other hand, the distance between the left lateral roll 813 and the right lateral roll 814 was set to a desired value in consideration of the burr preventing gap S1 (0.5 mm). These two sets of four rolls 811, 812, 813, and 814 have sufficient rigidity such as a roll housing and a roll journal so that the set value does not change even through a forming material with a groove.

  The longitudinal rolls 821 and 822 of the second-stage four-direction rolling mill 82 were set in substantially the same manner as that of the first-stage four-direction rolling mill 81A. However, the distance between the left lateral roll 823 and the right lateral roll 824 was set to a desired value in consideration of the warpage of the flange portion 20b of the workpiece.

  The vertical rolls 831 and 832 of the third-stage four-direction rolling mill 83 were set in substantially the same manner as that of the second-stage four-direction rolling mill 82. However, the distance between the left lateral roll 833 and the right lateral roll 834 was set to a desired value in consideration of the warp of the flange portion 20b of the workpiece.

  When the workpiece enters the multi-stage rolling mill 8 for squaring, the workpiece passes through the first four-way mill 81A, the second four-way mill 82, and the third four-way mill 83 continuously. The cross-sectional shape is sequentially changed from (a) to (b) in FIG. 6, from (b) to (c), and from (c) to (d). That is, in the first-stage rolling mill 81A, the material extruded outward by the upper vertical roll 811 is regulated by the tapered portion 814b and the concave portion 814c, respectively, and the corner portion c1 and the flange surface b2 in the vicinity thereof bulge outward. On the other hand, the material extruded outward by the upper vertical roll 811 was regulated by the tapered portion 812b and the concave portion 812c, respectively, and the corner portion c1 and the web surface a2 in the vicinity thereof were bulged outward. As described above, in the primary molded workpiece 201, the thickness T of the corner portion is increased in advance, and extra material (extra-wall) is accumulated in the corner portion c1.

  In the second-stage rolling mill 82, the flange length of the workpiece was reduced by the upper vertical roll 821 while restricting displacement in the width direction of the workpiece by the horizontal roll 824. As a result, the material of the corner c1 bulging outward and the flange 20b in the vicinity thereof is pushed back inward, and together with the material pushed back from the web 20a by the lower vertical roll 822, the material is brought into the corner c1 of the workpiece. Collected ingredients (meat). As a result, as shown in FIG. 6C, the corner c1 became sharper and the two-dimensional projection length Lp of the outer corner became smaller. The secondary molded workpiece 202 had a beautiful surface and an excellent appearance.

  The flare-like warp at the flange tip was corrected by passing through a third-stage four-way rolling machine 83. The horizontal roll of the third-stage four-direction rolling mill 83 functions as an overbend roll that corrects the spring back of the channel flange 20b, and has a tapered roll surface that slightly increases in diameter from below to above. I have. In this embodiment, the inclination angle of the tapered roll surface with respect to the vertical line is set to several degrees.

  With such a third-stage rolling mill 83, the flange 20b of the secondary formed workpiece 202 was slightly bent inward to correct the spring back, and the workpiece 203 shown in FIG. 6 (d) was finished. The finished formed work 203 shown in FIG. 6 (d) that has passed through the third-stage rolling mill 83 has a thickness t3, a flange length B3, and a web length H3 that are substantially the same as those of the secondary formed work 202 shown in FIG. 6 (c). Thus, a channel 203 was obtained in which the two-dimensional projection length Lp (X-axis length or Y-axis length of the map projected on the XY plane) of the outer corner portion c1 is 0.6 to 0.8 mm.

  The channel 203 obtained in this example has a flange length B3 of 25 mm, a web length H3 of 50 mm, a thickness t of 3 mm, and a two-dimensional projection length Lp of the outer corner shown in FIG. It had a sharp pin angle satisfying the relationship of .3t or less. The two-dimensional projection length Lp at the outer corner was measured nondestructively using an optical device such as a laser distance meter.

  Further, the channel 203 obtained in this example had a very good appearance inspection result with the naked eye, and both the web and the flange had a beautiful surface skin with metallic luster.

(Example 2)
As Example 2, the same material as that of Example 1 was prepared, and after the cold roll forming, three-stage square rolling was performed in the cold. In the present Example 2, it manufactured on the same conditions as the said Example 1 except performing cold rolling, without heating a material at all before square rolling.

  When the sample of this Example 2 was investigated, the external appearance and mechanical strength compared with the sample of Example 1 were obtained. However, in Example 2 (cold squeezing rolling), the roll was significantly consumed compared to Example 1 (warm squeezing rolling), and workability was reduced. Moreover, the method of Example 2 had a low yield compared to Example 1.

(Comparative example)
Next, a comparative example will be described. In addition, description of the part which a comparative example overlaps with said Example is abbreviate | omitted.
In the comparative example, except for the first stage rolling, the other conditions such as the rolling condition and the heating condition were the same as those in the above example. As the first-stage four-direction rolling mill of the comparative example, one in which the roll surfaces of the horizontal roll and the lower vertical roll of the first-stage four-direction rolling mill of the above-described example were changed was used. That is, in the first-stage four-direction rolling mill of the comparative example, the length L3 of the concave portion of the horizontal roll is 4 to 5 mm, and the gap S1 between the workpiece before rolling and the flat portion of the horizontal roll is 0.4 to 0.6 mm. The gap S2 between the workpiece before rolling and the concave portion of the horizontal roll is 1.5 to 1.6 mm, the total length L5 of the tapered portion of the lower vertical roll is 2 to 4 mm, and the concave length L4 of the lower vertical roll is The gap S3 between the workpiece before rolling and the concave portion of the lower vertical roll was 0.7 to 0.9 mm, and the curvature radius Re of the roll edge of the upper vertical roll was 0.5 mm. In addition, the same thing as the said Example was used for the 4 direction rolling mill of the 2nd stage and the 3rd stage.

  The preformed member 20 having the same size and the same material as the above-described example was square-rolled by using such a three-stage rolling mill for squaring. The primary forming channel 20B shown in FIG. 8B formed using the method of the comparative example has an excessively expanded portion, and the final finished product includes a web 20a and a flange 20b. A streak line defect clearly appeared along the boundary. This line defect greatly detracted from the appearance of the channel. The cause of the occurrence of the line defect is considered to be that the transition from the flat portion to the taper portion is abrupt in the lower vertical roll and the horizontal roll, and that the gaps S2 and S3 are too large. That is, in the comparative example, as shown in FIG. 8B, the amount of outward bulge in the first rolling process becomes excessive (too much meat accumulation), and the portion bulged to the corner c1 is the second portion. It is thought that it was not able to be fully pushed inward in the rolling process.

From the comparative consideration between this comparative example and the above example, the following matters could be derived as a conclusion.
(I) Providing a large gap between the roll surface and the outer corner of the work has an adverse effect, so that the recess in the roll surface has an appropriate amount.

  (Ii) Since the abrupt transition from the flat portion of the roll surface to the concave portion has an adverse effect, the inclination angle of the taper portion is moderated to sufficiently increase the length of the taper portion.

  The present invention can also be applied to shapes other than the channel, such as angle and hat steel.

  FIG. 10A is a schematic sectional view of an angle manufactured by a conventional method, and FIG. 10B is a schematic sectional view of an angle manufactured by the method of the present invention. The curvature radius R1 of the outer corner portion c2 of the conventional product 300 does not satisfy 0.3 times or less of the plate thickness t (R1> 0.3t), whereas the two-dimensional projection length of the outer corner portion c2 of the product 301 of the present invention. Lp satisfied 0.3 times or less of the plate thickness t (Lp ≦ 0.3t).

  FIG. 11A is a schematic cross-sectional view of a hat steel manufactured by a conventional method, and FIG. 11B is a schematic cross-sectional view of a hat steel manufactured by the method of the present invention. The curvature radius R1 of the outer corner portion c3 of the conventional product 400 does not satisfy 0.3 times or less the plate thickness t (R1> 0.3t), whereas the two-dimensional projection length of the outer corner portion c3 of the product 401 of the present invention 401. Lp satisfied 0.3 times or less of the plate thickness t (Lp ≦ 0.3t).

  The present invention is used for structural steels having various cross-sectional shapes, particularly lightweight structural steels for general structures such as channels, angles, and hat steels, and is limited to ferrous metal materials such as carbon steel and stainless steel. It is also used for non-ferrous metal materials such as titanium.

Schematic of the manufacturing line used for the processing method of the metal material which concerns on embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. The expanded sectional view which shows the principal part of the four-way rolling mill of the 1st stage shown in FIG. The schematic sectional drawing which shows the 4 direction rolling mill after the 2nd stage used for the processing method of the metal material which concerns on embodiment of this invention. The expanded sectional view which shows the principal part of the 4 direction rolling mill after the 2nd stage shown in FIG. (A)-(d) is a flowchart which shows the processing method of the metal material which concerns on embodiment of this invention. The figure which expands and shows the bending part of the channel processed using the method of this invention. (A) is a schematic sectional drawing of the conventional channel, (b) is a schematic sectional drawing of the channel of a comparative example. The schematic sectional drawing for demonstrating the fault at the time of arranging and welding the conventional channel side by side. (A) is a schematic sectional drawing of the conventional angle, (b) is a schematic sectional drawing of the angle of this invention. (A) is a schematic sectional drawing of the conventional hat steel, (b) is a schematic sectional drawing of the hat steel of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 ... Uncoiler 4 ... Cold roll forming apparatus 5 ... Oil draining apparatus 6 ... Heating apparatus 8 ... Multi-stage rolling mill 81A for a cornering ... First-stage four-way rolling mill (Example)
82 ... Second-stage four-way rolling mill 83 ... Third-stage four-way rolling mills 811, 812, 821, 822 ... Vertical rolls 813, 814, 823, 824 ... Horizontal rolls 811a, 812a, 814a, 821a, 822a, 824a: flat portions 812b, 814b of roll surface, tapered portions 812c, 814c of roll surface, concave portions 811b, 812d, 821b, 822b of roll surface, roll side surface 9, straightening machine 10, cutting machine 20, pre-formed member (square shape) Forming channel before processing)
201: Primary molding member (primary molding workpiece)
202 ... Secondary molded member (secondary molded workpiece)
203 ... Finished molded member (finished molded workpiece)
20B ... Comparative channel 20C ... Conventional channel 300 ... Conventional angle 301 ... Invention angle 400 ... Conventional hat steel 401 ... Invention hat steel S1 to S6 ... Gap a1 to a3, b1 to b3 Each surface c1 to c4 ... corner (right angle bend)
Lp: Two-dimensional projection length

Claims (5)

A preforming step to form a preformed member having a predetermined cross-sectional shape having at least one right angle bend by cold-forming a long metal material;
A first rolling step of forming a primary molded member having a bulging portion by bulging the outer side portion in the vicinity of both sides of the corner portion together with the corner portion of the preformed member cold or warm;
Push the bulging part cold or warm toward the inside of the corner, the two-dimensional projection length of the outer corner is Lp, the thickness of the side is t, the apex thickness from the inner corner apex of the corner to the outer apex A second rolling step for forming a secondary molded member having an outer corner that simultaneously satisfies the relationship of 0.5 mm ≦ Lp ≦ 0.3t and t <T, where T is T ,
A method for processing a metal material, comprising: In the first rolling process of claim 1 wherein the length of the perimeter to bulge outward, characterized by less than half of the respective side length on each side of the corner portion . In the first rolling step, claims, characterized in that the smaller than the radius of curvature Ri of the inner angle portion of the preformed member curvature radius Re of the roll edge of the vertical roll in contact with the interior angle portion of the preformed member 3. The method according to either 1 or 2 . Furthermore, after the said 2nd rolling process, it has the 3rd rolling process which correct | amends so that the cross-sectional shape of the said secondary shaping | molding member may become a desired shape, Any one of the Claims 1 thru | or 3 characterized by the above-mentioned. The method according to 1 . It is shape | molded using the method of any one of Claims 1 thru | or 4, The two-dimensional projection length Lp of an outer corner part is 0.5 mm or more, and is 0.3 times or less of the side thickness t. Metal processed products.

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