PRODUCTION OF HIGH TOUGHNESS AND HIGH TENSILE STRENGTH STEEL EXCELLENT IN SULFIDE STRESS CORROSION CRACKING RESISTANCE

摘要

PURPOSE: To provide a method for producing a high toughness and high tensile strength steel used in an environment requiring sulfide stress corrosion cracking resistance. ;CONSTITUTION: A slab having a compsn. contg. 0.04 to 0.09% C, 0.01 to 0.10% Si, 1.0 to 2.0% Mn, 0.1 to 1.0% Mo, 0.005 to 0.05% Nb, 0.005 to 0.03% Ti, 0.01 to 0.10% Al, 0.0005 to 0.005% B, 0.0040% N, and the balance Fe with inevitable impurities is heated at 1000 to 1150°C, is rolled at ≤950°C at a cumulative draft of ≥50% to the finish plate thickness and is thereafter subjected to direct hardening from the Ar₃ point or above. Successively, it is subjected to tempering treatment at the Ac₁ point or below. Thus, the high toughness and high tensile strength steel excellent in sulfide stress corrosion cracking resistance can be produced.;COPYRIGHT: (C)1996,JPO