Some thoughts on zinc alloy die casting
Zinc alloy die castings are widely used in various decorations. The most common defect of zinc alloy die castings is surface blistering. Defect characterization: there are protruding bubbles on the surface of die casting, which are found after die casting, polished or processed, and appear after oil injection or plating.
Causes:
1. Zinc alloy die casting intergranular corrosion causes:
Harmful impurities in zinc alloy composition: lead, cadmium, tin will gather at the grain boundary leading to intergranular corrosion, the metal matrix due to intergranular corrosion and broken, and electroplating accelerates this disaster, the corrosion of the intergranular parts will expand and the coating will be raised, resulting in foaming on the surface of the casting. Especially in wet environment, intergranular corrosion will cause deformation, cracking and even breakage of castings.
2. Zinc alloy die casting holes cause:
Mainly stomata and contraction mechanism, stomata are often round, and most of the contraction is irregular shape. (1) Causes of porosity: a metal liquid in the mold filling and solidification process, due to gas invasion, resulting in the surface or internal casting holes. B paint volatile gas intrusion. C alloy has high gas content and precipitates during solidification.
