Five types of defects in aluminum castings

Five types of defects in aluminum castings

It's not uncommon to encounter defects during the aluminium casting process. Some defects are small and can be easily fixed, while others are more severe and require us to throw out the casting and start over.

Obviously, this is far from ideal. Luckily, we have several ways to address these issues.

Here are the five main types of problems often found in aluminium castings:

     1. Shrinkage: This happens when the metal solidifies and shrinks. Open shrinkage defects appear on the surface, while closed shrinkage defects form within the casting when isolated pools of liquid remain within the solidified metal.

     2. Gas Porosity: Liquid aluminium can hold a lot of dissolved gas, but solid aluminium cannot. This can cause bubbles to form within the metal as it cools, leading to reduced overall strength. Gas porosity is usually caused by dissolved hydrogen in the molten metal.

    3. Pouring Metal Defects: Problems can occur when pouring the molten metal. It may not fill the entire mould cavity, leaving a portion empty. Alternatively, two sections of metal may not properly fuse within the mould, creating a weak spot.

    4. Metallurgical Defects: Sometimes, the chemical composition of the metal doesn't allow for optimal cooling. This can result in hot spots, which are hardened areas on the surface of the casting that cooled faster than the surrounding metal.

    5. Mould Defects: Hot metal is weaker, and if the mould is poorly designed, it can cause residual stress in the material as it cools. This can lead to hot cracking.

Treating these casting defects requires an individualized approach depending on the specific issue. However, as always, prevention is better than cure.

At EATHU, we have our own on-site laboratory dedicated to ensuring that all our castings are made with the finest metal.

You can rest assured in EATHU company customized products, we will provide the best quality assurance.