MANUFACTURE OF FINE-GRAINED HIGH TOUGHNESS STEEL PLATE FOR STRUCTURAL USE

摘要

PURPOSE: To economically manufacture a fine-grained high toughness thick steel plate for structural use with good productivity. ;CONSTITUTION: The slab of steel for structural use which is heated to ≥Ac₃ point after solidifying is applied to rolling reduction, if necessary, thereby the surface temp. is dropped to the temp. range of ≤Ar₃ point at ≥2°C/sec cooling rate. After that, it is recuperated, and the central part of the plate thickness is rolled at ≥30% draft in the temp. range of (the recrystallization finishing temp. to the recrytallization finishing temp.) +150°C. Once, the rolling is stopped, and cooling is executed to the ≤Ar₃ point surface temp. at ≥2°C/sec cooling rate. After recuperation, the central part of the plate thickness is rolled at ≥50% draft in the unrecrystallized region, and the rolling finishing temp. is regulated to ≥the Ar₃ point. In this way, the objective steel plate excellent in the toughness of the base metal can stably and economically be manufactured.;COPYRIGHT: (C)1993,JPO&Japio