Cracking Causes of 12Cr2Ni4A Carburizing Steel Squirrel Cage Elastic Support of Gas Turbine Engine

Multipe 12Cr2Ni4A carburizing steel squirrel cage elastic support strips cracked of a gas turbine engine. The cracking properties and causes were analyzed by macro and micro morphology observation, energy spectrum analysis, fracture analysis, chemical composition detection, finite element force analysis and fatigue and corrosion simulation tests. The results show that the cage strip cracking property was stress corrosion cracking occuring on the basis of superficial intergranular corrosion cracking. The cracked squirrel cage elastic support experienced excessive corrosion environment in the copper removal process, resulting in shallow intergranular corrosion. At the same time, the mechanical residual stress caused stress corrosion carcking and the high strength of the cage strip promoted stress corrosion cracking.