Fracture analysis for safety valve spring

The reasons leading to fracture for the safety valve spring was analyzed by means of morphology analysis, mechanical properties test, hardness test, metallographic test and other detection means. The results show that the cracks of spring are mainly characterized by intergranular brittle cracking, with sharp crack tips, obvious oxidation inside the cracks, and no obvious decarburization at the crack edges, which are typical quenching crack characteristics.