TItle：What is the design principle of the mold powder composition?
Description：Briefly introduced the composition of the mold powder material and the design principles
To realize the five functions of mold powder, the key is to formulate mold powder of suitable composition.
The mold flux slag widely used in continuous casting is based on the slag system composed of CaO-SiO2-Al203 ternary compound. And contains appropriate amount of Na2O, CaF2, K20 and other compounds. This kind of slag is weakly acidic or neutral liquid slag after melting, which has good wettability to molten steel, and the viscosity of the slag changes smoothly with temperature. Continuous casting mold powder is basically composed of three materials:
(1) Basic slag material. Basic slag material containing CaO, SiO2, Al203. According to the CaO-SiO2-Al203 ternary phase diagram, the composition range of these three compounds is: Ca0 10～38%, Si0240～60%, Al203 is less than 10%. The melting point is higher than 1300°C.
(2) Flux. Such as Na2O, CaF2 can reduce the melting point and viscosity of the slag. According to the resource situation, LiO2, K20, BaO, NaF, B2O3, etc. can also be used as fluxes, and the amount of addition depends on the melting point of the slag.
(3) Regulators. Carbon particles are melting rate regulators. The addition amount is 5 to 7%.
According to the requirements of the steel grade, the appropriate compound content of the mold flux is determined through experiments。