Fracture Analysis of Spring of Automotive Engine Valve

A spring of automotive engine valve was broken in bench test. By means of a variety of inspection and analysis on the appearance, chemical composition, microstructure, fracture morphology and fracture micro-area composition of the valve, the fracture reason of valve spring was analyzed. The results showed that the fatigue defects on the surface of valve spring was caused by improper storage of steel wire, resulting in early fatigue fracture.