Cause Analysis and Improvement Measures for Pipeline Cracking of 9Cr-1Mo Material

Abstract

The cracking reason of steam drainage pipe in a thermal power plant has been analyzed by means of alloy composition test, microstructure analysis and mechanical calculation. The results show that under the site layout and operation conditions, there were more water accumulated in the pipeline, the temperature of the pipeline decreased, and the movement of the drainage pipe was blocked by the floor, causing the stress of the drainage pipe socket exceeds the allowable value. The type IV creep crack was produced in the fine-grained zone of the heat affected zone of the pipe socket and the leakage failure occurred. The analysis clarifies the cause of cracking of steam drainage pipe and provides reference for avoiding similar cracks in 9Cr-1Mo materials.