AUSTENITIC STAINLESS STEEL CAST SLAB HARD TO DEVELOP HOT- ROLLED FLAW AND ITS PRODUCING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a cast slab hard to develop a hot-rolled flaw particularly developed in a continuous wire rod rolling, etc., regarding an austenitic stainless steel mainly used for welding material, and its producing method.;SOLUTION: This steel slab is the austenitic stainless steel containing 0.07-0.3% C, 10-30% Cr and K=0.28-0.01Cr-C0, and satisfies any condition of the ratio P≤20% of the grain boundary having width ≥2 μm to all grain boundary after being etched with 10% oxalic acid and after being continuously cast, the residual stress Q≤50 MPa and R=45P+4Q-2,900≤0. Further, this producing method employs cooling at ≥5°C/sec cooling speed from ≥1,000°C after casting or cooling at ≤0.4°C/sec cooling speed in the temperature range from 800°C to 400°C. Thus, the stress cracking of the grain boundary in the cast slab is reduced and the hot-rolled flaw is difficult to develop and the yield of production is improved and the repairing process to the flaw is dispensed with.;COPYRIGHT: (C)2001,JPO