Fremgangsmåte for fremstilling av höyfaste, seige sömlöse martensittiske rustfrie stålrör

摘要

PROBLEM TO BE SOLVED: To provide a method for producing a martensitic stainless steel seamless pipe having high strength and high toughness and little anisotropy.;SOLUTION: A martensitic stainless steel base stock is heated to austenitic zone and cooled after forming to a pipe stock with a piercing and a extension-rolling to substantially make this structure to martensite. Successively, the pipe stock is reheated to temperature in two phase region, and cooled after applying a finish-rolling at the starting temperature T of rolling in the range of the Ac₁ transforming point-Ac₃ transforming point to make the product pipe, and successively, a tempering is applied at not higher than the Ac₁ transforming point. Then, it is desirable that the finish-rolling satisfying 800 ≤ T - 0.625R ≤ 850 to the starting temperature T of rolling in the temperature of the Ac₁ transforming point-the Ac₃ transforming point and a cross sectional area reducing ratio R at 10-90%.;COPYRIGHT: (C)2004,JPO