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What causes bubbles in Zinc Alloy Die Cast Part during production?

Dec. 14, 2019
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A serious and frequent defect (blistering) of Zinc Alloy Die Cast Part has always plagued many die casting practitioners and die casting processing companies. Together, it has also caused skin peeling between large material suppliers and die-casting companies, polishing and electroplating companies, and small companies. Zinc alloy lead-zinc ore production process flow for processing zinc alloy die-casting system, casting and rolling. This kind of alloy has a low melting point and can be cast into a variety of precise and messy components. It has high mechanical strength, corrosion resistance, ductility, excellent forge ability and sensitive versatility. It is widely used to make high-quality components and products. Zinc alloy die-casting has good casting function can cast complicated shapes and thin-walled precision parts, and the appearance of the casting is smooth; does not attract iron during melting and die-casting does not corrode the mold, does not stick to the mold; has good room temperature mechanical functions and wear resistance Low melting the point, melting at 385 ℃, simple die-casting.

Zinc Alloy Die Cast Part

Zinc Alloy Die Cast Part

This problem needs to be resolved at this stage. The following is an explanation of the bubble phenomenon by Metal Acceeeories Manufacturer:

Zinc alloy die castings are now widely used in various decoration aspects, such as furniture accessories, construction and decoration, bathroom accessories, lighting parts, toys, tie clips, belt buckles, various metal decorative buckles, etc., so the quality requirements for the appearance of die castings are higher, Together demand outstanding appearance processing capabilities. The most common disadvantage of zinc alloy die castings is the appearance of blistering.

Characteristics of shortcomings: There are small bulges on the surface of the die-casting parts, which are found after die-casting, exposed after polishing or processing, or after injection or plating.

cause:

The hole caused by mainly stomata and shortening mechanism, stomata are often round and most shortening are irregular.

1. Reasons for stomata:

A. During the filling and coagulation of the molten metal, due to gas intrusion, holes appear on the outside or inside of the casting.

B. The gas evaporating from the paint penetrates.

C. the gas content of the alloy liquid is too high, it will be separated during condensation.

When the gas in the cavity, the gas evaporated from the coating material, and the gas condensed from the alloy is left in the mold when the tank is defective, the air holes formed in the casting will eventually remain.

2. Causes of shrinkage:

A. In the process of metal liquid coagulation, shrinkage occurs because of the volume is reduced or the final coagulation site cannot be refilled with metal liquid.

B. The castings with uneven thickness or part of the castings are overheated, forming a part that is too slow to condense, and when the volume is shortened, the appearance forms a concave position. Due to the presence of pores and shrinkage holes, water may enter the holes when the casting is being treated. When baking and spraying and plating are appropriate, the gas in the holes will expand due to heat or the water in the holes will change into steam and expand in volume, which causes blistering on the casting surface.

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