Internal Defects of Die Castings
Aluminum castings are widely used in auto parts, machinery manufacturing parts, computer parts, telecommunication parts, pump and valve parts, and other industries. The quality of aluminum alloy dies castings is affected by various factors in the actual production process. The internal defects of aluminum alloy die castings include pores, shrinkage holes, loose holes, inclusions, etc.
Features and inspection methods: After dissection, appearance inspection, or flaw inspection, the pore has a smooth surface and round shape.
①Use dry and clean charge, fewer impurities
②Using vacuum die casting
③ Guide the metal hydraulic pressure to balance, fill the cavity in an orderly manner, which is conducive to gas discharge
④ The exhaust groove should be set reasonably and have sufficient exhaust capacity
⑤ The paint with less energy is needed, the spraying should be thin and uniform, and the mold should be closed after the paint is exerted.
2. Shrinkage holes, Loose holes
Features and inspection methods: anatomical or flaw detection, the holes are irregular in shape, not smooth, and the surface is dark、Large pores and concentrated as shrinkage pores, small pores and dispersed as shrinkage porosity
①Reduce the pouring temperature and reduce the shrinkage
②Increase the specific pressure of injection and improve the compactness
③Modify the inner gate to make the pressure transfer better, which is beneficial to the liquid metal feeding effect
④Change the casting structure, eliminate the metal accumulation part, and make the wall thickness as uniform as possible
⑤Speed up the cooling of thick and large parts
Features and inspection methods: Metal or non-metallic impurities mixed into die castings, irregular shapes, points, or holes with different sizes, colors, and brightness are seen after processing.
①Use clean alloy material and the loot on the furnace needs to be cleaned up
②The alloy solution must be refined and degassed, and the slag should be cleaned up
③Clean the cavity and pressure chamber
④Control the temperature of the heat preservation