Reasons for cracking of impeller discs in centrifugal air compressors

A centrifugal air compressor impeller disc cracked and had debris falling off. The causes of the disc cracking were analyzed using methods such as macroscopic observation, chemical composition analysis, scanning electron microscopy observation and energy spectrum analysis, metallographic examination, and hardness testing. The results show that the erosion pits on the rounded surface of the wheel disc and blade were the source of cracks, and under the combined action of centrifugal force and S^－, Cl^－ corrosive anions, the wheel disc underwent intergranular stress corrosion cracking. There was a coarse overheated structure in the material, and its strength and hardness were relatively high, which promoted stress corrosion cracking of the wheel disc.