Structure of castings and air contact surfaces

The structure and air contact surface of castings! Because its castings cool and solidify faster in a metal mold than in a sand mold, the metal mold has no tolerance. Therefore, during metal mold casting, the casting stress that occurs in the castings is greater than that in sand mold castings, and there is a greater tendency for cracks. In the process of application, there is also a simple lack of pouring and cold insulation.

The wall thickness of castings should be uniform, and the transitions and connections between the walls should be smooth. The requirements for proper rounded corners at the corners of the product are more stringent than those for sand casting castings. The equipment should change the straight connected walls to skewed connections.

The relatively thin parts of the casting structure should be reinforced with ribs, protrusions, etc., which can effectively prevent casting cracks. During use, outstanding parts such as protrusions, ribs, flanges, etc. that prevent the casting from shortening freely should be minimized as much as possible.

When reinforcing ribs on castings, it is necessary to consider their impact on shortening the casting during use. This can prevent the occurrence of insufficient pouring and cold insulation in metal castings. The following structural issues should be noted.

The wall thickness of castings should be appropriately thin, especially when the casting scale is large. The product should be useful, and it is necessary to prevent large horizontal planes during use, because the metal liquid rises slowly during casting.

The structure and air contact surface of castings! The surface of castings that come into contact with air is large and prone to oxidation. Additionally, due to the fast heat dissipation of the metal, the flowability of the molten metal is quickly lost, resulting in shortcomings such as insufficient casting, slag inclusion, and cold insulation.