Cracking Reason of a 2A14 Aluminium Alloy Hydraulic Shell

By chemical component analysis, macro and micro observation of fracture, and metallographic structure testing, the cracking mode and causes of a hydraulic shell were analyzed. The results indicate that the cracking of hydraulic shell was stress corrosion cracking. The causes of the cracking were as the follwing:first, the design of the hole wall did not meet the standerds of istallation, which led to stress concentration in the thin part of the hole wall and produced tensile stress when the plug was pressed in.Meanwhile, the hydraulic shell worked in the sea and was affected by corrosive elements like Cl and S and thus stress corrosion cracking happened.