HIGH TENSILE STEEL WITH EXCELLENT LOW-TEMPERATURE TOUGHNESS, MANUFACTURING METHOD THEREOF AND MANUFACTURING METHOD OF DEEP DRAWING ARTICLE

摘要

PURPOSE: A steel material for high tensile deep drawing with a superior low temperature toughness, and a manufacturing method of the deep drawing product and a manufacturing method thereof are provided to perform the miniaturization of grain and the low temperature toughness enhancement effect. CONSTITUTION: A steel material for high tensile deep drawing with a superior low temperature toughness is as follows. The steel slab is re-heated in 1000~1250°C. The steel slab be rolling-finished in 750~1000°C. The steel slab is sphere and heat treats made after normalizing at a temperature of Ac1~Ac3. The steel slab is made of C: 0.25~0.40%, Si: 0.15~0.40%, Mn: 0.4~1.0%, Al: 0.001~0.05%, Cr: 0.8~1.2%, Mo: 0.15~0.8%, P: less than 0.015%, S: less than 0.015%, Ca: 0.0005~0.002%, Nb: less than 0.05%, B: 0.0005~0.0025% and Ti: 0.005~0.025%. The impurity which is inevitable the remnant Fe and others is included.