Causes of Bubbling in Aluminum Alloy Die Castings
Yurun aluminum zinc alloy die-casting parts are now widely used in various decorative aspects, such as furniture accessories, electronic parts, construction decoration, bathroom accessories, lighting parts, toys, tie buckles, belt buckles, various metal jewelry, etc. Therefore, high requirements are placed on the appearance quality of castings and good surface treatment performance is required.
Aluminum alloy die-casting
1、 Disadvantages: There are protrusions and bubbles on the surface of the die cast parts.
1. It was discovered when it was die-cast.
2. Exposed after polishing or processing.
3. Appears after oil spraying or electroplating.
2、 Cause of occurrence
Pores cause: mainly pores and shortening mechanisms, pores are often circular, while shortening is mostly irregular.
Causes of porosity occurrence:
(1) During the filling and solidification process of molten metal, the invasion of gas can cause holes to appear on the surface or inside of the casting.
(2) Gas intrusion from coating vapor announcement.
(3) The gas content in the alloy liquid is too high, and it separates when it condenses.
When the gas in the mold cavity, the gas released by coating evaporation, and the gas released by alloy condensation are left in the casting to form pores when the mold exhaust is poor.
The cause of shrinkage:
(1) Shrinkage occurs during the solidification process of molten metal due to volume reduction or the inability of the condensed area to be replenished by the molten metal.
(2) Uneven thickness of castings or localized overheating of castings can cause slow solidification in a certain area, resulting in a concave surface when the volume is shortened.
Due to the presence of pores and shrinkage holes, during surface treatment of die-casting parts, the holes may enter water. When baking after painting and electroplating, the gas inside the holes may expand due to heat. Or the water inside the hole will become vapor, causing the volume to expand, resulting in blistering on the surface of the casting.