Experimental study of bowing defects in pre-notched channel section products in the cold roll forming process

Abstract

In this study, the factors influencing bowing defects, which reduce quality in the cold roll forming of pre-notched products, are investigated by conducting experimental cold roll forming tests to produce symmetrical channel sections from pre-notched strips. The input parameters influencing bowing comprise factors that are related to the geometric characteristics of roll-formed products (including the distance between holes, distance between holes and strip edge, hole diameter, web and flange channel width, and strip thickness) and factors that are related to the cold roll forming line (including the forming angle increment or flower pattern, uphill and downhill strategies, horizontal distance between stands, and lubrication condition). Through a non-linear regression method, all the input factors were compared with each other to find the ones that are most and least influential on bowing. The obtained results showed that the forming angle increment and distance between holes had the greatest effects on bowing, so that increasing the number of forming stands from two to six reduced bowing more than five times. The results also showed that compared with other factors, the horizontal distance between stands, lubrication condition, and strip thickness have the least effects on bowing.