Ingredient Design of 1Cr13 Stainless Steel Continuous Casting Protective Slag

In the process of producing 1Cr13 stainless steel， serious longitudinal cracks breakout and transverse dents appear in the casting billet. FactSage8.2 thermodynamic software was used to calculate ternary and quadruple phase diagrams to design the ingredient of the protective slag. At the same time， the solidification characteristics of 1Cr13 stainless steel were calculated. As this steel is a peritectic steel， it will produce a sharp volume contraction during the solidification process， resulting in longitudinal cracks in the weak part of the blank shell. In order to avoid the dents and longitudinal crack caused by the uneven raw shell， the basicity of the protective slag should be improved， the crystallization property of the protective slag should be improved， and the heat transfer control ability of the protective slag should be improved too.The basicity of the new protective slag is 1.5， the slag is 6%MgO， 2%Li₂O， 16%Al₂O₃， 8%Na₂O， 3%B₂O₃， 10%CaF₂. The melting point of the original slag of 1Cr13 stainless steel is 1 155 ℃， the constant temperature viscosity is 0.442 Pa·s， and the transition temperature is 1 140 ℃. The melting point of the new protective slag is 1 120 ℃， the viscosity is 0.304 Pa·s， the transition temperature is 1 171 ℃， and the crystallization temperature is 1 270 ℃. After actual production， the surface quality of the casting billet is obviously improved.