Failure Analysis on Spring of Boiler Drum Safety Valve

摘要

Safety valve is an important component of a boiler. The failure of its spring will bring hidden trouble to the boiler operation. The fracture failure of a drum safety valve spring of a power plant boiler was discussed based on chemical composition analysis, hardness test, metallurgical microstructure observation and SEM. Results showed that improper material selection and improper heat treatment process which led to temper brittleness contributes to the fracture. In addition, oxygen corrosion pit on the surface of the spring play an important role in promoting the cracking.