In this paper, the temperature change curve of the casting and frozen sand mould during the solidification process of the A356 aluminum alloy in the frozen sand mould is tested. According to the actual temperature change curve of the casting surface and the sand mould surface, the interface heat transfer coefficient between the frozen sand mould and the A356 aluminum alloy could be reversed analysis. The results show that when the casting temperature is lower than 550 °C, the interface heat transfer coefficient remains about 750 W.(m2.K)-1; When the casting temperature is between 550 °C and 610 °C, the interface heat transfer coefficient increases significantly; when the casting temperature is higher than 610 °C, the interface heat transfer coefficient reaches the maximum value, which is about 2300W. (m2.K) -1. At this time, this study simulates the solidification temperature field of aluminum alloy hub parts in the frozen sand mould according to the interface heat transfer coefficient calculated by inverse analysis, and the temperature field of resin sand mould casting was used as for comparison. The results show that: under the same solidification time, the temperature field of A356 aluminum alloy hub parts in frozen sand mould is lower than that of resin sand casting, freezing casting can realize the high-speed solidification process of different parts of complex castings.

D igital patternless freeze-casting forming technology provides a green and rapid manufacturing method for single-piece and small-batch casting parts production in the fields of national defense industry, aerospace, power machinery, etc. [1]. The traditional sand mould casting process produces a large number of volatile organic compounds (VOC) and hazardous air pollutants (HAP) that are harmful to the human body and the environment. Of the 188 HAP listed by the U.S. environmental protection agency, more than 40 kinds have been detected in the sand mould casting process, including formaldehyde, benzene and phenol, etc. [2]. Therefore, it is urgent to develop new green casting processes and technologies.

In this paper, the casting process optimization design of a certain type of headstock is carried out by numerical simulation technology of casting process. Designed the pouring plan based on theoretical calculation; based on the numerical simulation results, quantitatively designed the riser size, and rationally arranged the pouring riser system based on the equilibrium solidification theory, which can reduce the shrinkage porosity and shrinkage defects in the casting process and increase the process yield; Finally, a sand core production plan is provided based on the precision machining technology of the moldless casting mold, which provides a new idea for the process plan design of complex spindle box castings.