Distribution Rule of Residual Stress Field of Zirconium Alloy Induced by Shot Peening
HUANG Xiao-bo;LIU Hong-fei;GAO Yu-kui;XU Kun-hao;School of Aerospace Engineering and Applied Mechanics, Tongji University;
The work aims to explore shot peening parameters applicable to zirconium alloy cladding tubes by means of different shot peening process. Zirconium alloy cladding tubes were treated by 9 different shot peening processes and numbered(from 1—9). Besides, residual stress fields of the treated cladding tube specimens were measured in both axial and transversal direction by adopting XRD residual stress measurement technique. The residual stress of untreated specimen in axial and transversal direction was-277 MPa and-250 MPa, respectively, and the maximum stress appeared in the outermost layer. Axial residual compressive stress on the specimens subject to shot peening treatment(number 2—8) was higher than that on untreated specimen, while the residual compressive stress on the surface subject to 9# treatment was lower than that on untreated specimen. This was probably because the shot peening intensity was too high, thus microcrack formed on the surface and then the re-sidual stress was released, shot peening intensity of the zirconium alloy cladding tubes should not exceed 0.40 mm A. For the higher intensity(above 0.15 mm A) shot peening process, such as 5—9 shot blasting process, the thickness of compressive stress affected layer was over 460 μm, almost the whole wall thickness of the cladding tubes subject to shot peening. Provided with same shot peening intensity and same projectile diameter, the surface compressive stress and the maximum compressive stress of glass projectile were close to those of stainless steel projectile. Thickness of compressive stress affected layer treated by glass projectile was nearly 80 μm thicker than that of compressive stress affected layer treated by stainless steel projectile. Provided with same shot peening intensity and the same projectile material, change in projectile diameter has little influence on surface residual stress and maximum residual stress in both axial and transversal direction. Meanwhile, the smaller the projectile diameter is, the deeper the maximum residual stress position in axial direction is; the larger the projectile diameter is, the deeper the maximum residual stress position in transversal direction is. As shot peening intensity on zirconium alloy increases(no over peening), the surface residual stress and the maximum residual stress increase in both directions.
【CateGory Index】： TG668