SCREW ROLL FORMING ROLLER FOR THIN-WALLED TUBE

摘要

PROBLEM TO BE SOLVED: To provide a screw roll forming roller for a thin-walled steel tube which is small in contraction, free from any tearing on a surface of a ridge, and capable of the forming on a smooth surface. SOLUTION: A screw roll forming roller 10 forms a screw by allowing a rotating work pressed thereagainst to plastically deform the work. The radius of the shape of a ridge and a bottom of the roller or a size of a flat surface is gradually increased so that the outside diameter of a male screw formed with reference to a tapered screw for tube specified in JIS B0203 is gradually decreased in ridge height than a tube end part.