WELDABLE HIGH STRENGTH STRUCTURAL STEEL NOT EMBRITTLED BY STRESS-RELIEVING ANNEALINGS

摘要

1,191,317. Steel. YAWATA IRON & STEEL CO. Ltd. July 18, 1967 [July 21, 1966], No.32875/67. Heading C7A. A weldable, high-strength, structural steel, which is not embrittled by subjection to repeated stress relieving anneals, comprises:- C less than 0À15% Si less than 0À5% Mn 0À5-2% Mo 0À2-0À5% Nb 0À03-0À2% optionally #V# 0À03-0À2% in total one or both #Zr# and optionally Ni 0À15-2% the balance, apart from impurities such as P and S, being iron. Heat treatment comprising heating to 930‹ C., air cooling, annealing at 650‹ or 625‹ C. and finally air cooling, may be used after hot rolling to form sheet.