wear and tear is due to castings in high-speed, vibration, overload and other operating conditions, the work between the mechanical surface friction between each other and lead to material wear and tear, and then make the material failure. Wear can be divided into various types such as abrasive wear, adhesive wear, fatigue wear, corrosive wear or micromotion wear. In machinery, abrasive wear is one of the more common forms of wear.

1. Material internal defects

Definition: metal or non-metallic material with a clear interface with the matrix. According to the nature can be divided into metal inclusions and non-metallic inclusions.

Effects: Reduces the effective cross-section of the metal casting, reduces the strength of the material and may lead to cracks.

Unreasonable structural design: such as the existence of stress concentration areas in the load-bearing parts, failing to properly design leading to failure.