COLD-ROLLED STEEL PLATE FOR HOT FORMING, HAVING EXCELLENT CORROSION-RESISTANCE AND SPOT-WELDABILITY, HOT-FORMED MEMBER, AND METHOD FOR MANUFACTURING SAME

• Main Authors: CHA, Jin-Ho, HEO, Si-Myoung, KIM, Seong-Woo, OH, Jin-Keun, CHO, Yeol-Rae, CHO, A-Ra, SEO, Jeong-Won
• Format: Patent
• Language: English; French; German
• Published: 14.07.2021
• 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

An aspect of the present invention relates to a cold-rolled steel plate for hot forming, which is excellent in corrosion-resistance and spot-weldability, contains, by weight %, C: 0.1-0.4%, Si: 0.5-2.0%, Mn: 0.01-4.0%, Al: 0.001-0.4%, P: 0.001-0.05%, S: 0.0001-0.02%, Cr: 0.5% to less than 3.0%, N: 0.001-0.02%, and a balance of Fe and inevitable impurities, satisfying formula (1) below, and includes an Si amorphous oxidation layer continuously or discontinuously formed at a thickness of 1nm-100nm on the surface thereof. Formula (1) : 1.4 ≤ 0.4*Cr + Si ≤ 3.2 (wherein element symbols denote measurements of respective element contents by weight %).