MANUFACTURE OF COLD ROLLED STEEL SHEET FOR DEEP DRAWING BY BOX ANNEALING

• Main Authors: KATO HIROSHI, WATANABE TAKAHITO, TOYODA HIROTAMI, KOYAMA KAZUO
• Format: Patent
• Language: English
• Published: 01.02.1986
• Subjects: ALLOYS; CHEMISTRY; FERROUS OR NON-FERROUS ALLOYS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; TREATMENT OF ALLOYS OR NON-FERROUS METALS

PURPOSE:To manufacture economically a cold rolled steel sheet for deep drawing superior in material quality by hot and cold rolling suitably a steel having a specified compsn. contg. C, Mn, S, P, sol Al, N, then box annealing said rolled sheet at a specified temp. range. CONSTITUTION:The steel contg. >=0.01% C, >=0.05% Mn, <=0.015% S, <=0.015% P, 0.010-0.08% sol Al, <=0.00025% N, beside satisfying Mn%+8XC%<=0.47, Mn%+5XC%>=0.20, and the balance Fe with inevitable impurity elements is hot rolled so that cumulative draft at <=1,000 deg.C is regulated to >=87% and end temp. of finishing rolling is controlled to >=Ar3 transformation point temp., successively, cold rolled by >=70%. Thereafter, said rolled sheet is box annealed at 650-750 deg.C temp. range, to obtain the cold rolled steel sheet for deep drawing having soft material quality, high ductility, high Lankford value and aging resistance.