Aluminum alloy gravity casting is to use metal casting to obtain aluminum alloy and castings of parts. Gravity casting of aluminum alloy has fluidity, shrinkage, warmth, air tightness, casting stress and gettering. Casting slag is oxidation slag, which is mostly distributed on the upper surface of the casting and the corner of the mold. After casting, cracks will be found on the surface of some castings. What are the reasons for this phenomenon?
1. Casting cracks. It is a kind of crack formed at higher temperature. It is easy to appear in alloys with large volume shrinkage and castings with complex shape.
2. Heat treatment cracks. It often presents transgranular cracks due to overburning or overheating of heat treatment. It is often over cooled in alloys with large stress and thermal expansion coefficient. Or other metallurgical defects.
In the process of analyzing the defects of aluminum alloy gravity casting, another phenomenon is the porosity of the casting. The pores have smooth surface and are round or oval in shape, mainly on the surface of the casting, or subcutaneous pinholes, or possibly inside the casting, which is also one of the defects that need to be solved by gravity casting manufacturers.
Editing: WMM