JPS61289901A - Cold roll forming method for light channel steel with less deformation at cut end - Google Patents

Abstract

PURPOSE:To decrease the deformation at the cut ends of a light channel steel by setting the ratio between the contact projection length between a pressing roll and flange part and flange height at a specific value and exerting the compressing force of a prescribed compression rate toward the corner part from the end edge of the flange. CONSTITUTION:A lower roll 10 and an upper roll group 20 are disposed and the compressing force is exerted to the flange part Kb therebetween. The compression of the flange part Kb s executed near the final stage of cold roll forming. The contact projection height between the pressing roll 21a and the flange part Kb is made >=1/4.5 the flange forming height. The compressing force of which the compression rate is adjusted to a 2.0-4.0% range is further exerted toward the corner part from the end edge of the flange Kb. The residual bending moment and torsional moment remaining in the flange part Kb are thereby made uniform and the light channel steel having the decreased deformation at the cut ends is obtd.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a cold roll forming method for light groove section steel with less cut deformation, which can form the light groove section steel so that its cross-sectional shape does not change due to cutting.

[Conventional technology]

Conventionally, light groove sections have been formed from copper strips using a cold roll forming method, as explained in the drawings below.
When the light groove steel formed by the cold roll forming method is cut in this way, a phenomenon occurs at the cut end with one opening and one closing. Figure 3 is a forming perspective view showing the progress of forming a light groove section steel using the cold roll forming method, Figure 4 is an end view showing the shape at each stage of forming in Figure 3, and Figure 5 is completed forming. Figure 6 is a perspective view showing the state of deformation near the cut when the light groove section steel is cut, and Figure 7 is an end view of the light groove section steel after it is assembled into a structure. It is a perspective view showing one example. As shown in FIG. 3, while the steel strip S is continuously running in the direction of the arrow
, C, D, E, and F (only the positions are shown in the figure) are used to sequentially transform both sides into the shape shown in the end view of each roll stand in Figure 4, and the final stage is roll stand F.
In this case, the web portion is cold roll formed into a light groove-shaped steel K having a desired shape having flanges Kb on both sides of a as shown in FIG. The deformation of the steel strip S is continuous, but an example of the progressing state of deformation is shown in the deformation angle θ of the steel strip S at each roll stand (the position of each roll stand is shown as a subscript) as shown in Fig. 4. 19. =15°θ, 3=3o
' θC-45°e, =60613E-85' θF
=90'.

[Problems to be solved by the invention]

When the light groove section steel K formed by such a conventional cold roll forming method is cut, the flange part Kb near the cut end is deformed, as shown in Fig. 6, and the copper strip travels during cold roll forming. On the upstream side, a closing phenomenon occurs in which the internal angle (indicated by α in Fig. 6) of the corner formed by the web part Ka of the cut of C and the flange part b becomes small, and at the same time, a closing phenomenon occurs in the downstream side K.
There is a drawback that an opening phenomenon occurs in which the internal angle α of the corner portion of the cut d becomes large. This kind of phenomenon is a light groove! This is thought to be due to the presence of a residual bending moment M and a residual torsional moment l-T in the flange part of the AK, but when such mouth closing and opening phenomena occur, the web of the light groove section steel At the edge of the flange part farthest from part 8, a predetermined dimension Y of 1 on both sides of the light groove section, KtJ on the downstream side, and Kc on the upstream side.
The difference between the dimensions Y, , Y, between the edges of both flanges 813Kl) at each cut, that is, (Y. -Y,), (Y, -Y,) is two to three times the thickness of the steel strip. 4. The length of the deformed region where the dimension between the edges of b on both flanges differs from the predetermined dimension Y0.
Although L varies depending on the shape and material of the light groove type MK, it is usually 4 to 6 times the height of b at the flange portion. Therefore, when such a mouth closing phenomenon or mouth opening phenomenon occurs, a notch formed in the flange part Kb' of one light groove shape #4 using the light groove shape steel K as shown in FIG. Insert the other light groove section K into e' and make both light groove sections,
Even if an attempt is made to automatically assemble a structure by welding the abutting parts of the two, the abutment condition is poor and the automatic assembly cannot be carried out, resulting in high construction costs for the structure. It was. As a result of research to eliminate the drawbacks of bending, the present inventors previously reported in Japanese Patent Application Laid-Open No. 56-163030 that when forming a thin plate material (copper strip) into a pumice section by roll forming, at an intermediate stage, The deformation angle θ is calculated by the plate thickness and the side wall (
A method of roll forming a lightweight section steel is disclosed in which -H overbending is performed to form an angle within a predetermined range defined by the height of the flange (flange portion), and then roll forming is performed to a predetermined final angle (90 degrees). This method is very effective when the copper strip constituting the lightweight section steel is a thin sheet material with a thickness of less than 2.3 mm, but it is not suitable for thick sheet materials with a thickness of 2.3 mm or more. In the end, it was insufficient to effectively prevent the phenomenon of mouth-closing.

[Means to solve the problem]

Therefore, as a result of further intensive research, the present inventors found that in order to equalize the residual bending moment and residual torsional moment that remain in the flange portion of pumice section steel, it is necessary to We found that it is effective to apply compressive force from the edge of the flange toward the corner, and as a result of further investigation, we found that it is effective to apply compressive force from the edge of the flange toward the corner. After researching the effectiveness of
A patent application has been filed for a cold roll forming method for lightweight section steel with minimal cut deformation. However, when continuously cold roll-forming light groove sections from copper strips, it is insufficient to specify only the compressive stress applied to the flange section by a pressure roll near the final stage of cold roll-forming. It has been newly established that the compressibility of the flange part must be within a predetermined range in a state where the projected contact length W of the pressure roll and the flange part and the flange height h satisfy the relationship, and the relationship is satisfied. The present invention was completed by investigating the following. That is, in the present invention, the height of the flange is increased by h by the rolls of the multi-stage roll stand while the copper strip is continuously run.
When cold roll forming a light groove section steel, the flange part is formed under the condition that the projected contact length W between the pressure roll and the flange part is h/4.5 or more near the final stage of cold roll forming. A light groove shape with little cut deformation, characterized in that a compression force with a compression ratio in the range of 2.0 to 4.0% is applied by a pressure roll from the edge of the flange toward the corner of the flange. This invention relates to a method for cold roll forming of steel. Hereinafter, the method of the present invention will be explained in detail with reference to the drawings. Fig. 1 is a vertical cross-sectional explanatory view of an example of a roll stand with a pressurizing device preferably used in carrying out the method of the present invention, and Fig. 2 shows the final stage of cold roll forming while carrying out the method of the present invention. It is a side view which shows the relationship between a pressure roll and a flange part near a stage. In the method of the present invention, as shown in Fig. 3, while the steel strip S is running, it is sequentially deformed by the rolls of a multi-stage roll stand so that it becomes a light groove steel with a flange height of h, which is different from the conventional method. There is no difference. In the method of the present invention, near the final stage of cold roll forming, when the copper strip is sequentially deformed by the rolls of multiple roll stands and the internal angle of the corner portion becomes approximately 90 degrees, that is, the final finishing roll is applied. If it exists, the projected contact length W between the pressure roll and the flange portion before finishing with the R finishing roll.
The compression ratio t of the flange part under the condition of tfh/4.5 or more
A compressive force in the range of f2.0 to 4.0% is applied from the edge of the flange toward the corner of the flange by a pressure roll. In this way, when a light groove steel with a flange height of h is cold roll-formed by the rolls of a multi-stage roll stand while the copper strip is continuously running, the pressure roll is applied near the final stage of cold roll-forming. The reason why the projected contact length W between the pressure roll and the flange must be h/4.5 or more is that if the projected contact length Wtf between the pressure roll and the flange is less than h/4.5, the flange and web This is because sufficient compressive stress is not applied to the corner parts, which are the boundaries between the parts, and the light groove section steel with little cut deformation, which is the object of the present invention, cannot be formed. A compression force in the range of 0 to 4.0% must be applied by a pressure roll from the edge of the flange toward the corner of the flange if the compression rate of the flange is less than 2.0%. It is not possible to completely equalize the residual bending moment and residual torsional moment that remain in the flange due to the compressive force applied by the pressure roll from the edge of the flange toward the corner of the flange. If the compression ratio of the flange part applied by the pressure roll from the edge to the corner part of the flange part exceeds 4.0%, the compression force applied to the flange part by the pressure roll becomes very large, causing the pressure roll to deteriorate significantly. If it is not large, the durability will be lost and the cost will be reduced, and the residual bending moment and residual torsional moment I that remain in the flange will be made uneven again in the direction of 0 and formed into a light groove-shaped steel with less cut deformation. This is because it will not be possible. In addition, the compression ratio (%) of the flange portion mentioned above can be determined by the following formula. [(T1-h) ÷ H) The pressure applied by the pressure roll toward the corner of the copper strip may be applied by a pressure device installed separately from the roll stand for deforming the copper strip, but it is also possible to apply pressure by adding a pressure device to the roll on the roll stand. A roll stand with a pressurizing device may also be used. An example of such a roll stand with a pressurizing device will be outlined with reference to FIG. A lower roll 10 is rotatably attached to a fixed frame 40 by bearings 12 at both ends of a lower roll shaft 11. Reference numeral 21 denotes an upper roll, which constitutes the upper roll group 20 together with a space roll 22 sandwiched between the two upper rolls 21, and an upper roll shaft 23 passing through these.
is rotatably attached to a pressurizing frame 30 which can be moved up and down by bearings 24 on both sides, and both ends of an upper roll shaft 23 that protrudes further from the bearings 24 move only in the vertical direction of the elongated hole of the fixed frame 40. The upper roll group 20 can be moved up and down together with the pressure frame 30 by looking through the upper roll group 20 so as to obtain the upper roll group 20 . The upper part of the pressurizing frame 30 is connected to a hydraulic cylinder 32 through a bottle 31, and the hydraulic cylinder 32 is further connected to a hydraulic unit 33. The flange end holding part 21a of the upper eyelid 21 is hardened, hard chrome plated, etc.
It is important that the diameter of the flange end holding portion 21a is sufficiently large so as to satisfy the condition that the projected contact length W between the pressure roll and the flange portion is h/4.5 or more, as described above. In the upper roll group 20, the gap between the upper roll 21 and the space roll 22 can be adjusted depending on the plate thickness, the dimensions and shape of the light groove steel, and the like.

[Effect]

If a light groove section steel in the final stage of cold roll forming is introduced using such a roll stand with a pressurizing device, the wear part will have a
The lower surface runs in contact with the top of the lower roll 10, and the flange part b is introduced into the gap between the upper roll 21 and the space roll 22, and the end edge of b is brought into the flange part by the operation of the hydraulic cylinder 32. - The flange end pressing portion 21a of the flange portion 21 applies a compressive force to the flange portion such that the compression ratio b is in the range of 2.0 to 4.0%. In this case, even if the light groove section steel has a symmetrical shape, in the actual molded product, the height h of b on the left and right flanges is, for example, 0.1 to 1.5 mm.
Even in such a case, the upper roll shaft 23 is adapted to be able to tilt, so that the pressure against b can be equally applied to the left and right flange portions, although the degree may vary. In this way, in the final stage of cold roll forming, the compression ratio of b on the flange part is 2.0 to 4.0 under the condition that the projected contact length of b between the pressure roll and the flange part is Vlh/4.5 or more. A compressive force in the range of It will become.

【Example】

Hereinafter, the method of the present invention will be explained in more detail with reference to Examples. Example Type 2 rolled steel for general structural use with a thickness of 4.5IllIIl (
SS41)-1 was continuously passed through a six-stage roll stand as shown in Fig. 3, so that the width of the web part was 200 m and the height of the flange part was 7 m.
A 5 mm light groove section was manufactured by cold roll forming method. At that time, a roll stand with a pressure device similar to that shown in Fig. 1, in which a pressure roll with a diameter of 300 mm in the flange holding part is installed next to the sixth roll stand, is used, and from the edge of the flange part The compression ratio of the flange part toward the corner part is 1.0.1.5°2.0.3.0.3.5.4.
A compression force of 0% was applied using a pressure roll to obtain a light groove section steel in each case. Each light groove section was cut as shown in Fig. 6, Y, Y, of the cut end was measured, and W-(Y, -Y,)/2 was defined as the amount of deformation at the cut end. As a result, the relationship between the compression ratio and the amount of cut deformation was as shown in the table below. As can be seen from the table below, under the condition that the projected contact length W between the pressure roll and the flange is h/4.5 or more, the compression ratio of the flange is in the range of 2.0 to 4.0%. It has been found that when force is applied from the edge of the flange toward the corner of the flange using a pressure roll, a light groove section steel with extremely small cut deformation of 1.0 ml or less can be obtained. . table

【effect】

As described in detail above, the method of the present invention is suitable for cold roll forming a light groove section steel with a flange height of h using the rolls of a multi-stage roll stand while continuously running a copper strip. In the step, the compressive force is applied to the flange so that the compression ratio of the flange is in the range of 2.0 to 4.0% under the condition that the projected contact length W between the pressure roll and the flange is h/4.5 or more. This is a method that allows you to obtain light groove-shaped steel with little cut deformation by cold roll forming by adding a simple process of applying pressure rolls from the edge toward the corner of the flange. There are many things that contribute to the production and use of

[Brief explanation of the drawing]

Fig. 1 is an explanatory longitudinal cross-sectional view of an example of a roll stand with a pressurizing device preferably used in carrying out the method of the present invention, and Fig. 2 shows the final stage of cold roll forming in which the method of the present invention is carried out. 3 is a forming perspective view showing the progress of forming light groove section steel by the cold roll forming method, and Fig. 4 is a side view showing the relationship between the pressure roll and the flange section in Fig. 3. FIG. 5 is an end view of the light groove section steel after forming is completed; FIG. 6 is a perspective view showing the state of deformation near the cut when the light groove section steel is cut; FIG. 7 is a perspective view showing an example of a state in which light groove sections are assembled into a structure. 10...Lower roll 11...Lower roll shaft 12...Bearing 20...Upper roll group 21...Upper roll 21a...Flange end holding part 23... Upper roll shaft 24...Bearing 30...Pressure frame 31...Bin 32...Hydraulic cylinder 33...Hydraulic unit 40...Fixed frame A, B, C, D, E, F... On the roll stand, Ni'... Light groove section 1 (a... Web part Kb, Kb'... Flange part Kc... Upstream side Kd ...Downstream side K e l ... Notch S ... Copper strip X ... Copper strip running direction Fig. 4 Fig. 5 ℃ - J rod Fig. 6 Fig. 7 □・6-1-1

Claims (1)

[Claims] 1. Near the final stage of cold roll forming when a light groove section steel with a lower flange height is cold roll formed by rolls of a multi-stage roll stand while the steel strip is continuously running. Under the condition that the projected contact length W between the pressure roll and the flange is h/4.5 or more, the compression ratio of the flange is 2.
A cold roll of light groove-shaped steel with little cut deformation, characterized in that a compressive force in the range of 0 to 4.0% is applied from the edge of the flange part toward the corner part of the flange part by a pressure roll. Molding method.