JPS6233012B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a cold roll forming method for preventing deformation of a cut end surface when cutting a long molded product obtained by cold roll forming a irregular cross-sectional material.

When cold roll-forming a metal strip gradually into a predetermined shape through a number of roll stands, the conventional method is to install side rolls from the outside of the strip between the stands of the upper and lower roll stands. It is being Since both the upper and lower rolls and side rolls incorporated in the stand perform molding from the same direction, residual strain remains in the molded product in the same direction, and when cut at an arbitrary position, the cut surface portion was significantly deformed. Therefore, after cutting a continuously molded product using a cut-off press, the deformation of the cut surface was manually corrected and reworked. This is extremely inefficient, and it has been desired to establish an efficient and stable forming method using cold roll forming.

The present invention uses a cold roll forming apparatus having a large number of stands, and vertically rotating rolls are provided inside the molded product in the width direction between the stands, and bending is performed by up-and-down forming, and return forming is performed by the vertically rotating rolls. To provide a cold roll forming method that prevents deformation of the cut end surface after cutting by reducing unidirectional forming distortion caused by forming rolls.

The strip that is being formed into the desired cross-sectional shape is subjected to residual strain in a certain direction by forming rolls during the forming process, so the residual stress distribution in the center of any longitudinal direction of the molded product remains in an equilibrium state, making it stable. are doing. However, once the molded product is cut at an arbitrary position, the residual stress loses its balance and the cut surface becomes deformed. The most common deformation state of the cut surface is that along the molding direction, the entrance side (tip) shrinks and the exit side (rear end) expands, but this depends on the cross-sectional shape of the molded product and the requirements for molding. Depending on the number of molding stands used, etc., a spreading phenomenon may occur at both the leading and trailing ends. The present invention will be described below with reference to examples using a cold roll forming method using so-called repeated bending, in which conventional bending and back-forming operations are performed in order to reduce the directionality of residual stress in a molded product.

1 and 2 show schematic diagrams of a forming stand for cold roll forming, FIG. 1 showing a plan view thereof, and FIG. 2 showing a side view thereof. In this example, the desired molded product is molded from molding stands No. 1 to No. 4, and molding is performed sequentially from No. 1, and molding is completed at No. 4, and molding is completed at No. 3 and No. 4.
In this case, the idling roll of the present invention is provided inside the molded product, and a bending mechanism is incorporated therein. Figure 3 is a cross-sectional diagram of the strip plate to be formed in Figures 1 and 2, showing V-V, WW, X-X, Y-Y, respectively.
This is a Z-Z cross section.

In FIGS. 1 to 3, each of the forming rolls includes forming rolls 2 and 3, forming rolls 2 and 3, and forming stand No. 1 in which the strip 1 to be formed is assembled into forming stand No. 1 by transmitting power from a drive device built into the forming roll device. .2, the forming rolls 4 and 5, hereinafter forming rolls 6, 7, 8, and 9, are used to successively perform pass forming to continuously form a desired cross-sectional shape. In this case, vertical idler rolls 10 and 11 are respectively installed between forming stands No. 3 and No. 4 so as not to interfere with each other in order to perform the unbending forming. Bending back forming, that is, the bending angle is A
The relationship of >B and C>B is maintained, and the amount thereof can be freely selected depending on the moment of inertia of area during molding, that is, the strength of lateral rigidity and the strength of the strip. The contact portions 12, 12' between the vertical idle rolls 10, 11 and the strip provide a bending action. That is, by forming the product at a bending angle from A to B and then to C, the direction of molding strain is changed and the directionality of residual stress in the molded product is reduced. In other words, the present invention aims to reduce the directionality of the residual stress generated by the combination of the longitudinal feeding motion of the material to be formed and the forward bending from the flat strip toward the cross-sectional shape of the product, preferably at the end of the forming process. This can be alleviated or eliminated by adding a back-molding process. This makes it possible to prevent the deformation of the cut end that is peculiar to cold roll forming due to the directionality of residual stress. If the unbending angle difference AB, CB is small, the effect of one unbending action is small. The unbending angle difference is selected in consideration of the shape of the strip to be formed, mechanical properties, quality, etc. of the strip to be formed. In this embodiment, there is one set of vertical idle rolls that perform this unbending, but as described above, depending on the shape of the strip to be formed, the mechanical properties of the strip to be formed, the quality, etc., two or more sets may be used between the stands. Can also be used in pairs. Furthermore, a bending back action is employed between the plurality of stands to achieve more stable molding. still,
Although the bending process requires experience and skill to determine the position during the forming process depending on the cross-sectional shape, it is generally more effective to incorporate it from the middle to the latter half of the forming process. Although the vertical idle rolls 10 and 11 shown in the YY cross section of FIGS. 2 and 3 are provided on the same cross section, the effect of the bending action does not change even if they are not necessarily on the same cross section.

As an example, a lightweight channel steel plate with a thickness of 2.3 mm and a height of 100 mm
As a result of molding by passing through eight stands for molding with a side of 50 mm, the strip to be molded was cut. At that time, the deformation of the cut end was 4 mm, but when the bending process of the present invention was provided between the 6th stand and the 7th stand and between the 7th stand and the 8th stand, and the cut end was cut after forming, the cut surface was deformed. was reduced to 1.5 mm, confirming that cutting strain was extremely reduced.

As explained above, the following effects can be obtained by using the cold roll forming method of the present invention.

(1) Since the deformation of the cut surface of the molded product is small, the quality of the molded product is significantly improved and it can be used for multipurpose purposes such as architectural parts and mechanical parts.

(2) Productivity is improved and labor can be saved because there is no need to modify the cut surface for deformation.

[Brief explanation of the drawing]

Fig. 1 is a schematic plan view of a forming device that forms a strip through a multi-stage roll stand, Fig. 2 is a side view,
Figure 3 shows V-V, W-W, X-X, Y-Y, Z-
A Z cross section is shown. 1...Strip plate to be formed, 2-9...Roll, 10,
11... Vertical free roll.

Claims (1)

[Claims] 1 In a cold roll forming method for forming a shape material having an irregular cross section by continuously cold roll forming a metal strip through a number of stands, a set of vertical idlers provided in the width direction between arbitrary stands is used. A roll is provided inside the metal strip to be formed in the bending direction, and the forming rolls before and after the vertically rotating rolls perform bending, and the vertically rotating roll performs back-forming to eliminate forming distortion of the metal band to be formed. A method for preventing end widening of cut edges in cold roll forming.