Through analysising,geted the main reason of creating crack is a loose layer existing at the outside side of the conjunction slice of the chain,and there are many defects at outside of the link bore.

The unconsolidated overburden is composed of residual soil, clinosol and stream sediments.

During stress corrosion cracking of Cu3Au alloy, there is a dealloyed layer on the surface because of preferential dissolution of Cu, and there is a linear distribution of Cu vacancy concentration in the dealloyed layer.

Effect of electric current pulse on shrinkage cavity and porosity in casting ZA27 alloy;

Factor Analysis and Countermeasures of Porosity and Pipe in Ingot;

In this paper, analysis on the fissuring accident of ZGMn13Cr2Mo antifriction tup is performed, and the reason is believed to lie in serious casting defects of shrinkage cavity, porosity and inclusion.

Results indicate that the primary cause to the rupture of the screw in the process of torque force test is proved to be heavily existence of holes and pore gaps in the screw arising from the central looseness of the original billet.

Mechanism of central parosity and looseness of small billet is described and analysed.

The experimental results show that there are some internal metallurgy flaws such as looseness,shrink hole in the raw material of the axle,and bad widmanstatten structure from the overheating and over-burning during the heating of forging,the comprehensive effects of these factors cause the steel toughness to reduce,and the internal cleavage exists d.