To provide a method and apparatus for producing a tapered steel pipe by which the generation of a wavy surface in the initial stage and the middle stage of working is suppressed and also cracks in the later stage of the working are prevented even when it is necessary to remarkably contract the diameter of a steel pipe.
In the method for producing the tapered steel pipe just after forming the portion of the steel pipe with the drawing roller R is cooled with cooling water when tapering the steel pipe W by bringing a drawing roller R of a drawing device into contact with the peripheral surface of the steel pipe W while heating the steel pipe W by passing through a heating device H, the degree of cooling is reduced in accordance with progression of the working of the steel pipe W during working.
NAKAYA TAKESHI
YAMAMOTO HIROAKI
KOJIMA HIROSHI
Tsutomu Inoue