Calculation of volume shrinkage of wheel hub flange by investment casting sand casting

The molding process of impeller investment mold sand mold composite casting is the key content of the whole process, which is directly related to whether the impeller casting can fill and shrink smoothly, and whether the surface quality and dimensional accuracy of the casting can meet the technical requirements. This part mainly includes the design of casting gating system (riser), sand mold casting modeling of impeller hub and spoke, and the molding process between molten shell and sand mold.

Considering the fitting error between the impeller investment casting sand casting mold shell and the mold and the pouring and riser processing factors of the upper mold, the machining allowance of the upper horizontal plane of the impeller is 5mm, the machining allowance of the lower plane is 3mm, and the machining allowance of the single side of the core is 5mm.

Because the process scheme of setting riser on impeller investment casting sand casting rim for feeding and setting riser with gate on wheel hub is selected, the design of casting gating system (riser) mainly focuses on the design and verification of riser. The riser size is calculated by modulus method.

The volume shrinkage of carbon steel is related to the carbon content in steel and pouring temperature. The volume shrinkage of alloy steel is greater than that of carbon steel. It is related not only to the carbon content and pouring temperature, but also to the alloy elements and their content.

Component elementComponent %Element influenceMetal liquid shrinkage ε (%)

When the pouring temperature of impeller investment casting sand casting is 1600 ℃, check the relevant manual and calculate the volume shrinkage of zg1cr18ni9ti from the table ε The total shrinkage is 5.952% ε= 6%。 Due to the low content of titanium, the effect on volume shrinkage can be ignored.