Cause Analysis on Fracture of Valve Spring of VDSiCrV Steel

The valve spring of the engine of a certain automobile fractured during driving. The fracture causes of valve spring were analyzed by means of macroscopic observation, chemical composition analysis, metallographic examination, inclusion analysis, hardness test, scanning electron microscope analysis and surface quality analysis. The results show that the early fatigue fracture of the valve spring was caused by many factors such as metallurgical defects (inclusions), low hardness of the material and surface oxidation corrosion.