FLUORIDE-FREE CONTINUOUS CASTING MOLD FLUX FOR ULTRALOW CARBON STEEL

摘要

A fluoride-free continuous casting mold flux for ultralow carbon steel, comprising the following components in weight percentage: 3-10% of Na 2 O, 0-3% of Li 2 O, 3-8% of MgO, 5-15% of MnO, 0-8% of BaO, 4-12% of Al 2 O 3 , and impurities with a content of no more than 2%, the balance being CaO and SiO 2 , wherein the ratio of CaO/SiO 2 is 0.8-1.3; the raw materials are mixed and then pre-melted; the pre-melted mold flux requires micro-adjusting according to the component deviation, and the ratio of the pre-melted material is not lower than 70%; then a carbonaceous material of 1-3% by the total weight of the mold flux is added and mixed so as to obtain the finished product mold flux. Said mold flux has a melting point of 1100-1200°C and a viscosity of 0.2-0.6 Pa·s at 1300°C. A method for preparing a mold flux comprising the following steps: mixing raw materials, pre-melting to obtain a pre-me then continuously supplementing raw materials into the pre-melt to obtain a substrate with a desired composition; then adding a carbonaceous material to the substrate and mixing so as to obtain said mold flux. This mold flux is a boron-free and fluride-free mold flux, can effectively reduce the inclusion defect of blank casting and increase the yield of blank casting.