Reasons for cracking of the scaleplate frame flange of a compressor clearance cylinder

Cracks occurred at the flange of the left clearance cylinder scaleplate frame of a certain compressor. The reasons for the cracking of the scaleplate frame were analyzed using methods such as macroscopic observation, metallographic examination, scanning electron microscopy analysis, indentation test, mechanical performance testing and scale composition analysis. The results show that the strength of the material for the scaleplate frame was insufficient, and the chamfer between the substrate and the connecting flange was small, resulting in stress concentration at this location. Cracks initiated and continued to expand within the large－sized graphite sheet at the stress concentration location, ultimately led to cracking of the scaleplate frame.