METHOD OF PRODUCING HIGH-STRENGTH THICK STEEL PLATE EXCELLENT IN BRITTLE CRACK PROPAGATION ARREST PROPERTY

摘要

PROBLEM TO BE SOLVED: To provide a method of producing a thick material excellent in brittle crack propagation arrest properties and having a plate thickness of ≥40 mm.;SOLUTION: The method of producing a high-strength thick steel plate excellent in brittle crack propagation arrest properties and having a texture in which {100}011 orientation density on a rolled surface in a plate thickness-direction center part is ≥3.5, is characterized by including a step in which: a steel raw material having a composition containing, by mass%, 0.01-0.20% C, 0.01-0.80% Si, 0.20-2.50% Mn, ≤0.020% P, ≤0.0070% S, 0.003-0.100% sol. Al, 0.003-0.20% Ti, 0.003% Nb and the balance comprising Fe with inevitable impurities, is heated to 1,000-1,200°C and rolled in an austenitic recrystallized temperature zone, thereby obtaining a rolled steel plate; then the rolled steel plate is rolled at a cumulative draft of ≥60% in an un-austenitic recrystallized temperature zone; and thereafter, the rolled steel plate is heated from the temperature of Ar₃ transformation point to the austenitic recrystallized temperature zone at a temperature rise rate of ≥2°C/sec; and is acceleratedly cooled from the temperature of ≥the Ar₃ transformation point to ≤600°C.;COPYRIGHT: (C)2013,JPO&INPIT