1.Crack make the casting produces stress concentration, which is not available as a waste. 

2.Deformation affect the dimension accuracy of castings and geometry, increased the rejection rate. 

3.The deformation of complicate the machining process, increase the machining difficulty. 

4.Such as castings have tiny crack, application and practice, seriously affect the using performance. 

5.Change the mechanical properties of castings declining plasticity, toughness, strength, hardness increases. 

How to produce high quality parts, to save material, energy, and shorten manufacturing time and improve the economic benefit will be of great significance.