Research on thermal insulation subsidy process of large steel castings

The application of thermal insulation subsidies to replace metal subsidies in large steel castings is still very small. In this paper, the E-δ/M relationship for determining the thickness of the insulation subsidy under the condition of substituting the metal subsidy for the insulation subsidy in the literature has been revised to make the result more accurate. It is pointed out that the maximum effect of the modulus enhancement of the thermal insulation subsidy is the ratio of the heat storage coefficient of the sand mold and the thermal insulation subsidy. After this range, the thickening thermal insulation subsidy will no longer meet the thermal insulation requirements. The large-scale thick plate type specimen 1 200 mm × 1 200 mm × 180 mm was selected, and its thermal insulation subsidy process scheme was designed and optimized. The simulation results found that since the thickness of thermal insulation subsidy is smaller than the metal subsidy, it is necessary to use thermal insulation subsidy for the lower part of the riser due to the use of thermal insulation subsidy. The surface exposed to the sand mold is insulated with thermal insulation subsidies, otherwise the feeding channel is prone to necking at the neck of the riser. The castings were poured with metal subsidy and thermal insulation subsidy respectively. Flaw detection and dissection of the casting plate showed that there were no internal defects in the casting. Both the pouring results and the numerical simulation results show that the thermal insulation subsidy can replace the metal subsidy. However, large-scale steel castings require insulation subsidies to have high heat resistance, otherwise it will easily lead to deformation of the castings