Development of Roll-Less Forming Process for Ultra-Thin Wall Welded Pipe Production

Summary

A new thin wall welded pipe production process named “ROLL-LESS FORMING” was developed. It makes use of the resultant cross directional curvature due to preforming (strip is continuously bent and unbent in the longitudinal direction) to produce thin wall welded pipes. Since roll-less forming does not need the forming rolls used in the conventional methods such as the roll forming process, additional advantages on productivity, installation costs and surface damage can also be expected. The preforming process and characteristics of roll-less forming were investigated by theoretical analysis and several experiments. Based upon the results, it was clarified that roll-less forming is extremely suitable for production of ultra-thin wall welded pipes which have been difficult by the conventional methods, and the available pipe dimensions by roll-less forming is approximately from 0.3% to 1.2% in t/D.