PRODUCTION OF HIGH TENSION STEEL HAVING EXCELLENT RESISTANCE TO HYDROGEN INDUCED CRACKING

摘要

PURPOSE:To obtain a high tension steel having excellent resistance to hydrogen induced cracking by subjecting a steel material contg. C, Si, Mn, P, S, Ca or REM, Al and Ti, B respectively at prescribed ratios to hot rolling then to tempering in a specific temp. range. CONSTITUTION:A steel material contg., by weight, 0.02-0.15% C, 0.05-0.80% Si, 0.8-2.0% Mn, =0.025% P, =0.005% S, 0.001-0.010% Ca or REM, 0.005- 0.10% Al, 0.003-0.10% Ti and 0.0003-0.003% B is prepd. Such steel material is hot-rolled and is then tempered at 500-700 deg.C. The resistance to hydrogen induced cracking is thus considerably improved without deteriorating the mechanical property of the steel material and the high tension steel having the excellent resistance to hydrogen induced cracking is produced inexpensively in a large amt.