STAINLESS ALLOY STEEL UNDERGOING HARDLY SURFACE CRACKING DURING HOT ROLLING AND METHOD FOR HEATING ITS SLAB

摘要

PURPOSE:To reduce surface defects caused on a stainless alloy steel slab by cracking during hot rolling by specifying the amount of sol. Al added to the stainless alloy steel having a specified composition and by regulating the concn. of O2 in the atmosphere in a furnace when the slab is heated. CONSTITUTION:A stainless alloy steel is provided with a composition contg., by weight, 0.001-0.20% C, 0.10-5.0% Si, 0.1-11.0% Mn, =0.050% P, =0.020% S, 11.0-30.0% Cr, 2.0-3.0% Ni, 0.001-0.060% N, =0.015% O, =5.0% Mo, =3.0% Cu, =1.0% Nb, =0.05% Ti, =0.10% Zr, =0.06% Ca and =0.10% Sn and/or =0.05% B. The concn. of O2 in the atmosphere in a furnace is regulated to 0.5-5.0% and a slab of the steel is heated in the atmosphere. Thus, S and O2 in the steel are made harmless, so the occurrence of surface defects due to cracking during hot rolling is prevented.