Abstract: Based on the abnormal fracture of screw compressor screw in the whole machine operation, combined with its cross section characteristics, the paper has verified the failure reason by comprehensive analysis and verification of chemical composition analysis, hardness analysis, hydrogen embrittlement resistance test, metallographic analysis and non-metallic impurity electron microscope test. The failure reason is that the screw material contains too many inclusions, and the heat treatment process is abnormal and the leading factor is abnormal, the impact toughness and fatigue resistance of the screw are further reduced, which leads to the screw fracture. The paper has certain reference and guidance significance for the fracture analysis of the screw.

Key words: Screw of screw compressor, Brittle fracture, Dimple, Inclusion, Alumina