How to avoid common defects in precision castings？

Measures to prevent oxidation and slag inclusion: Strictly control the smelting process, quickly smelt, reduce oxidation, and thoroughly remove slag. Aluminum magnesium alloy must be melted under a covering agent. The furnace body and tools should be clean, free of oxides, and preheated. The paint should be dried after use. The designed casting system must have stable flow, buffering, and slag skimming capabilities. Adopting a tilted pouring system to ensure stable liquid flow and prevent secondary oxidation. The selected coating has strong adhesion, and slag is formed inside the casting during the pouring process without peeling off.

Measures to prevent thermal cracking: In actual pouring systems, local overheating should be avoided to reduce internal stress. The mold and core slope must ensure the above 5 degrees, and the inverted riser can be formed by core pulling during solidification. Sand cores can replace metal cores when necessary. Control the thickness of the coating to ensure consistent cooling speed of the casting. Select the appropriate mold temperature based on the thickness of the casting. Refine the alloy structure and improve its thermal cracking ability. Improve the structure of castings, eliminate sharp corners and sudden wall thickness changes, and reduce the tendency for hot cracking.

Measures to prevent loose production: Reasonable riser setting to ensure solidification and shrinkage ability. Reduce the working temperature of the metal mold appropriately. Control the coating thickness to reduce the thickness of thick walls. Adjust the cooling rate of each component of the metal mold to provide greater cooling capacity for the thick walled castings. Reduce the pouring temperature of the metal appropriately.