METHOD FOR MANUFACTURING STEEL PLATE WITH EXCELLENT HYDROGEN-INDUCED CRACKING RESISTANCE, AND THE STEEL PLATE

摘要

PROBLEM TO BE SOLVED: To provide a method for manufacturing a steel plate having excellent hydrogen-induced cracking resistance by which the development of hydrogen- induced cracking can be prevented with certainty, and to provide the steel plate. SOLUTION: The steel plate is composed of acicular-ferrite-like single-phase structure and the grain sizes of contained nonmetallic inclusions are estimated, and maximum matrix hardness is regulated so that the grain sizes of at least≥90% of the nonmetallic inclusions satisfy the relation of (grain size of nonmetallic inclusion)≤-0.7×(maximum matrix hardness)+250. COPYRIGHT: (C)2003,JPO