METHOD FOR MANUFACTURING A TWIP ULTRA-HIGH STRENGTH STEEL SHEET TO ENHANCE THE ELONGATION AND THE YIELD AND TENSILE STRENGTHS AT THE SAME TIME

摘要

PURPOSE: A method for manufacturing a TWIP(Twin Induced Plasticity) ultra-high strength steel sheet is provided to enhance the elongation of the TWIP ultra-high strength steel sheet by making the crystal grain finer.;CONSTITUTION: A method for manufacturing a TWIP(Twin Induced Plasticity) ultra-high strength steel sheet is as follows. A hot rolled steel sheet of certain composition is processed through cold rolling including four or more passes. The steel sheet is recovery-annealed at 200~220°C after 3 passes. The steel sheet is annealed. The composition comprises C(Carbon) 0.15~0.30wt.%, Si(Silicon) 0.01~0.03wt.%, Mn(Manganese) 15~25wt.%, Al(Aluminum) 1.2~3.0wt.%, P(Phosphorus) 0.020wt.% or less, S(Sulfur) 0.001~0.002wt.%, and the rest iron and inevitable impurities.;COPYRIGHT KIPO 2010