来源：六合历史开奖记录 发布时间：2020-02-13 21:59:38 点击：
As aluminum alloy has a simple oxidation and aspiration tendency, and the smelting process directly contacts with furnace gas or external atmosphere, if the control in the smelting process is a little improper, aluminum alloy is easy to absorb gas and form pores, the most common is pinholes. Pinhole usually refers to the precipitation hole of the casting below 1mm, which is mostly round and distributed unevenly on the whole casting section, especially on the parts with thick section and low cooling rate of aluminum alloy die casting. According to the distribution and shape characteristics of the precipitated pores in aluminum alloy, pinholes can be divided into three types.
1. Mesh pinhole: in low-power organizations, pinholes are closely connected to form a network, including several large holes. It is not convenient to calculate the number of pinholes per unit area, and it is also difficult to measure the diameter of pinholes.
2. Punctate pinhole: low power tissue pinhole is round and punctate, with clear contour and discontinuity. The number of pinholes per square centimeter area can be counted and its diameter can be measured. This kind of pinhole is easy to be distinguished from shrinkage cavity and shrinkage cavity.
3. Comprehensive pore: it is the middle type of punctate pinhole and reticular pinhole. From the point of view of low organization, there are many large pinholes, but most of them are polygonal rather than circular and punctate.
The production practice of aluminum alloy die casting has proved that the main gas component of the air hole formed by suction aluminum alloy is hydrogen. Materials are no exception, various components of aluminum alloy easily produce pinholes.
The above is the detailed introduction of porosity of Shandong Aluminum alloy die casting. For more information, please click