US 10,092,948 B2 · Fluoride-free continuous casting mold flux for low-carbon steel

Abstract

The invention provides a fluoride-free continuous casting mold flux for low-carbon steel, comprising, based on weight, Na2O 5-10%, MgO 3-10%, MnO 3-10%, B2O3 3-10%, Al2O3≤6%, Li2O<3%, C 1-3%, and the balance of CaO and SiO2 as well as inevitable impurities, wherein the ratio of CaO/SiO2 is 0.8˜1.3. The mold flux has a melting point of 95˜1150° C., a viscosity at 1300° C. of 0.1-0.3 Pa·s, and a crystallization rate of 10-50% as determined according to the method described in the specification for examining crystallization property. The boron-containing, fluoride-free flux developed according to the invention has a moderate crystallization rate, can be used in a crystallizer to control transfer of heat from molten steel effectively, and has been applied successfully in a low-carbon steel slab conticaster with a metallurgical effect that arrives at the level of a traditional fluoride-containing flux to full extent.

Claims7

Dependent claims

A fluoride-free continuous casting mold flux suitable for producing low-carbon steel, consisting of, based on weight, Na2O 6-9.5%, MgO 3-10%, MnO 3-10%, B2O3 3-4%, Al2O3≤6%, Li2O<3%, C 1-3%, the balance of CaO and SiO2, and inevitable impurities, wherein the weight ratio of CaO/SiO2 is 0.8˜1.0;

wherein the crystallization rate of the mold flux ranges from 22% to 50% as characterized by the proportion of crystals at a section when 50g of the mold flux is melted at 1350° C. and then poured into a steel crucible to be cooled naturally;
and wherein said mold flux has melting point and viscosity of heat transfer capability suitable for producing low carbon steel in a continuous casting system.

Dependencies are inferred from the claim text.

Fluoride-free continuous casting mold flux for low-carbon steel

Life of this patent

Fluoride-free continuous casting mold flux for low-carbon steel

Life of this patent

Abstract

Claims7