Common Defects in Foundry Castings
At Calhoun Foundry, our mission is to deliver high-quality highly cored, intricate castings for automotive and O.E.M. A key issue faced by foundry operators across the world is casting defects. From mold material mishaps to shrinkage defects, Calhoun Foundry recognizes the meticulous precision required to pour perfection into every project. Here are the most common casting defects encountered in metal casting and how to avoid them.
Gas Porosity
Causes:
When molten metal solidifies, it tends to trap air within its structure, leading to potential gas porosity defects as the metal cools down and releases the trapped gas.
Prevention:
Preventing Gas Porosity defects involves creating a less humid casting environment. This necessitates the exclusion of excessive moisture by employing dry, permeable sand exclusively. Also, maintaining molds and cores meticulously, ensuring they remain moisture-free is critical.
Shrinkage
Causes:
Shrinkage defects occur because metal contracts as it cools down after casting. If this process isn’t managed properly, you get a misshapen or weakened product. Poor mold design or incorrect pouring temperature can lead to these issues.
Prevention:
The prevention of metal shrinkage defects is centered around strict temperature control. Foundry temperatures must be carefully regulated to ensure even thermal conditions at all points in mold filling, cooling, and finishing.
Mold Material Defects
Causes:
Mold material defects in castings can arise from factors such as improper mold preparation, inadequate ventilation leading to gas entrapment, or the presence of impurities in the mold material
Prevention:
Ensuring defect-free castings requires meticulous mold design and preparation, employing proper ventilation and superior mold materials. It's crucial to maintain strict control over casting parameters. Mold maintenance might be required.
