SU917399A1 - Method for making asymmetrical bent sections - Google Patents

Description

The invention relates to the processing of metals by pressure, in particular to the production of asymmetrical curved rolled sections in rolls of roll forming mills.

There is a known method for producing asymmetrical curved profiles, in which the profile shelves are bent at different angles because the torsion moment is zero relative to the center of gravity, and at the last transitions they turn the wall around the profiling axis to the larger side.

shelves 1 3

The disadvantage of this method is the helical twisting of the profiles due to insufficient consideration of the process features.

The aim of the proposed method is to improve the quality of the profiles by preventing their helical twisting.

To this end, in the method of production of asymmetrical curved profiles, in the multi-transition bend, the angle of the greater side wall ot, hail

The profile elements in the rolls, in the process of bending the profile elements, move the center of gravity of its cross section in a plane perpendicular to the axis of the rolls.

FIG. Figure 1 shows a breakdown of the cross-section of an asymmetrical tub profile into elements; in fig. 2 - three transition in the production of asymmetrical channel according to the proposed method.

Position 1 indicates the first transition, position 2 indicates pre-transition transitions, position 3 finishes transitions, position 4 indicates traces of a flatness, perpendicular to the axis of the rolls, in which is the center of the body of cross-section of the profile of all transitions.

So, for example, the profiling mode of an asymmetrical channel YuOh x 80x50 mm of steel St. 3, determined by the proposed method, is given in the table.

Bend angle

walls

u hail

6

15

2C

32

C

56

69

83

To obtain the finished profile of the proposed method, it took 8 technological transitions. The helical twisting of the finished profile was - 1 on 1 running meter, which is in

10 2k

39 52 66 86

k 8. 90 90

deeds of the requirements of GOST 8281-69 Steel, cold-folded, Channel unequal-legged. Assortment.

For the asymmetric trough profile, according to the proposed method, the hem angles of the lesser side wall in each transition are determined from the equation: (bc, b cochc1, c), b, (± b, 4b oo54b2 (), (| b b 05, b ) -L, P ,, -the thickness of the elements of the profile, -absssissa of the center of the cross section of the cross section of the section, the cross-sectional area of the cooking; h 2. the wall width; p is the desired angle of the lower side wall} cL - angle of bending of the greater side wall (determined by the method of expert estimates based on practical experience). In the manufacture of asymmetric g For the purpose of high-quality forming of the bend between the wall and the smaller side wall, fixing the inner surface of the bend with the upper roller begins to bend the wall only after the bending angle p of the smaller side wall reaches 90, while the wall and the smaller side wall. bend together as a rigid integer. In this case, an equation similar to equation (I) also contains two unknown values — the angles cL vt y, which are determined similarly to pre-. to the previous one. . According to the experimental verification data, the proposed production method allows, in comparison with the known, to prevent distortion of the finished profile by preventing the screw-like twisting in the process; profiling according to the known - 1 -. 1 30 running meter); expand the assortment of complex unequal-strength curved profiles (due to profiles whose production has not previously been mastered due to technological difficulties), reduce mill downtime by reducing the time for adjustment and adjustment by 20-30% (due to a decrease in the number of technological transitions); reduce the number of technological transitions by 15-20 (for example, for the production of an asymmetrical channel of 100x80xTCOx4 mm, according to a known method .10 technological transitions were required, and according to the proposed method, only 8 transitions). The economic effect will be obtained by improving the quality of the profiles, reducing the number of technological transitions and mill downtime for reducing the time for adjustment; y and adjustment.

Claims (1)

(54) METHOD FOR PRODUCING ASYMMETRIC BENT PROFILES, including multi-jib bending of profile elements in rolls, characterized in that, in order to improve the quality of profiles by preventing their helical twisting, the center of gravity of its cross section is moved in the process of bending of profile elements to the perpendicular axis .