Ferrite stainless steel plate null mass for the ferritic stainless steel welded tube and the welded tube which are superior in

摘要

PROBLEM TO BE SOLVED: To provide a welded ferritic stainless steel tube which is free from tube expanding working crack and constriction occurring in a base material part at eccentric tube expanding working to at least two times the diameter of a tube stock and has excellent tube expanding workability.;SOLUTION: The welded ferritic stainless steel tube is: (1) a welded ferritic stainless steel tube in which elongation in a circumferential direction of the base material part of the welded tube is ≥15%; (2) a welded ferritic stainless steel tube which has a composition containing, by mass, 0.001 to 0.015% C, 0.001 to 0.020% N, 11 to 25% Cr, 0.01 to 2.0% Mo, 0.05 to 0.6% of either or both of Ti and Nb and 0.0003 to 0.0030% B and also has ≥30% elongation in a direction to be a circumferential direction of the tube stock for the welded tube and ≥1.5 average Lankford value.;COPYRIGHT: (C)2006,JPO&NCIPI