| 摘要 |
PURPOSE: A method for manufacturing a duplex stainless steel is provided to reduce oxygen concentration inside molten steel and slab in order to secure hot workability, thereby minimize cracks generated in a hot roll process. CONSTITUTION: A method for manufacturing a duplex stainless steel comprises: a first step of implementing a first deoxidation by injecting Si with 27 to 33kg of Al per ton of slag into molten steel; a second step of deslagging after the first deoxidation; a third step of manufacturing the slag for a second deoxidation; and a fourth step of implementing the second deoxidation by injecting Al for the second deoxidation into the molten steel. The duplex stainless steel includes 0 to less than 0.030 wt% of C, 0.35 to 0.65 wt% of Si, 1.4 to 1.7 wt% of Mn, 0 to less than 0.03 wt% of P, 0 to less than 0.0010 wt% of S, 22.1 to 22.6 wt% of Cr, 5.05 to 5.45 wt% of Ni, 2.5 to 2.7 wt% of Mo, 0 to less than 0.005 wt% of Ti, 0 to 0.5 wt% of Cu, 0 to 0.15 wt% of Al, Fe, 20 to 35 ppm of B, 1650 to 1900 ppm of N, and other inevitable impurities. The injectable amount of Al for the second deoxidation is as much as the generation amount of metallic oxides and the amount of Al among the molten steel are adjusted into 400 ppm. |
