Reason for White Spot Defect on Surface of Zr-3 Zirconium Alloy Sheet

After surface treatment by resin wheel grinding and pickling in production, white spot appeared on surface of Zr-3 alloy slabs. The cause of the white spot was analyzed by chemical composition analysis, microstructure observation and residual stress test. The results show that the white spot was caused by excessive residual stresses. The white spot defect was eliminated by application of thousand impeller grinding or sand blasting to decrease surface residual stresses and reduce twin crystal formation.