JPS5481157A - Manufacture of welded box-shaped steel - Google Patents

Abstract

PURPOSE: To obtain welded box-shaped steel of large size with ease of welding by the procedure in which flange width is specifically defined for one of channel steels to be combined, the forming of channel section is finished prior to welding, and then at weld position, only channel steel of small flange width is bent at a specific angle.

CONSTITUTION: The width dimension of upper and lower steel belts drawn out of uncoiler is set up to a fixed dimentional difference (A) and then molded by turns into the following form by forming rolls (illustration is omitted) of plural tiers. Namely, the flange width Bu of the upper channel steel 1 is formed to less than 2 times the plate thickness t and the forming angle of flange and web is bent into 90°, the forming angle of final product. On the other hand, the width of the web of the lower channel steel is made to an extremely large width enought to supplement the shortage of flange width of the channel steel 1. Then, the both steels are combined at the weld position D and contacted against the squeeze roll 3 at the upper and lower positions of the weld point W. At this time, bending deformation is given to the channel steel 1 alone and a 2 to 7 deg V-shaped angle α is formed between it and the channel steel 2, where the weld point W is centered. Then, the upper and lower flange edges are welded.

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