Analysis on Fracture Reason of Support Ring Plate

The support ring plate valve of CuNi2Si copper alloy was fractured in service for one year. By means of chemical composition analysis, metallographic examination, microhardness testing, fracture and energy spectrum analysis etc, the fracture reason was analyzed. The results showed that there was plastic deformation in local plate under installation prestressing force and work stress; and with the common role of environmental media, stress corrosion cracks occurred in the slit where the wall of support ring plate was contacted with arched positioning tube, leading to stress corrosion cracking produced early in support ring cover.