304奥氏体不锈钢喷丸引起的组织转变和两相残余应力测定

Microstructure changes and residual stresses of each phase caused by shot peening in 304 austenitic stainless steel

采用X射线衍射技术研究了304奥氏体不锈钢喷丸过程所引起的组织结构变化以及两相组织中每相的残余应力。试验结果表明,喷丸强化可使亚稳态304奥氏体材料表面发生γ→α转变,在相同的喷丸强度下转变量与喷丸弹丸种类规格关系很大,而且与喷丸时间有关;表面两相组织γ和α相各自的残余应力可采用X射线衍射应力仪进行测定,两相的残余应力数值相差很大。

The phase transformation and residual stress induced by shot peening in 304 austenitic stainless steel were investigated. The volume fraction of austenite phase and martensite phase and residual stress of each phase were determined quantitatively by X-ray diffraction. The results indicate that the volume fraction of austenite phase and martensite phase is a function of peening intensity and peening time and that volume fraction of martensite phase increases with the increase of the time of shot peening. The time to shot peening and peening intensity are two main parameters. The saturated time to ensure 100% coverage is not enough to ensure the maximum volume fraction of martensite phase caused by shot peening under the same peening intensity.