The invention relates to medium
carbon steel casting powder for H-section steel
continuous casting, belonging to the technical field of
steelmaking and
continuous casting. The medium
carbon steel casting powder comprises the following components in percentage by weight: 33-39 percent of CaO, 35-39 percent of SiO2, 4-7 percent of Al2O3, 0-3 percent of MgO, 5-9 percent of F<->, 10-12 percent of Na2O, and balance of composite carbon which comprises 7 percent of
graphite and 1-2.5 percent of
carbon black, wherein the CaO and the SiO2 are used as base materials; and the Na2O, the MgO, the Al2O3 and the F<-> are used as flux. A preparation process comprises two steps, i.e. the step of producing pre-molten materials and the step of producing finished product
casting powder. The prepared casting powder has physical properties that the
melting point is 1080-1096DEG C, the
viscosity at 1300DEG C is 0.17-0.35Pa.s and the melting speed is 30-40s. The thickness of the molten flux layer of the casting powder is 10-13mm. According to the requirement of
carbon steel on the casting powder during production of an H-section steel
continuous casting machine, the flux film control goals of lower
melting temperature, lower
viscosity, proper melting speed and higher
thermal resistance are realized, and the situation that the surface of a casting blank is longitudinally cracked because the
temperature gradient of the cross section of the casting blank is too large is avoided. The medium carbon
steel casting powder has a better using effect than the using effect of domestic and
foreign similar products, and can fully meet the process requirement on the carbon steel during H-section steel continuous casting.