Casting process analysis of new superalloy for automobile

According to the test results of high temperature wear resistance and high temperature oxidation resistance of the new superalloy used for automobile turbocharger turbine, the optimum casting process parameters are 1360 ℃ pouring temperature and 1100 ℃ mold preheating temperature.

Only the appropriate pouring temperature and mold preheating temperature can refine the grain size, improve the microstructure of the alloy, increase the toughness and compactness, and improve the high-temperature wear resistance; if the pouring temperature or mold preheating temperature is too low, there will be inclusions and other defects; at the same time, if the temperature is too high and the internal energy is too high, the grain will coarsen and the wear resistance will decrease. In the test of high temperature oxidation resistance, the oxidation rate of the alloy is accelerated and the mass added value per unit area is increased. With the increase of pouring temperature and mold preheating temperature, the mass gain value per unit area of the sample decreases gradually, which slows down the oxygen diffusion and enhances the oxidation resistance; however, when the pouring temperature exceeds 1360 ℃ and the mold preheating temperature exceeds 1100 ℃, the excessive temperature will aggravate the surface oxidation degree of the alloy.

Therefore, in order to improve the high temperature wear resistance and oxidation resistance of superalloy, the pouring temperature is 1360 ℃ and the preheating temperature of die is 1100 ℃.