METHOD FOR MANUFACTURING TENSILE STRENGTH 1.5GPA CLASS STEEL SHEET AND THE STEEL SHEET MANUFACTURED THEREBY

摘要

PURPOSE: A method for manufacturing super high-strength steel sheets with tensile strength of 1.5GPa and steel sheets generated through the same are provided to manufacture super high-strength steel sheets with tensile strength of tensile strength more than 1.5Gpa and over 7% of elongation percentage. CONSTITUTION: A method for manufacturing super high-strength steel sheets with tensile strength of 1.5GPa is as follows. The alloying element of molten steel sheets satisfy the relational expression of Si+Al+P / MnΔ0.5, 5ΔC+1.5Mn+2Cr+Mo+BΔ12 and C+Mn / 20+Si / 30+2*P+4*SΔ0.52 and a slab is manufactured through continuous molding. The slab is reheated and coiled. A rolled strip is cold-rolled in 30 to 70% reduction ratio. The cold-rolled strip is reheated and slowly cooled.