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利用化学、电化学及金属物理方法分别研究了喷丸对304L不锈钢SCC性能、电化学行为和表层组织结构的影响,讨论了喷丸提高不锈钢SCC抗力的作用机理。得到如下结论:①喷丸可提高304L不锈钢在高温水和沸腾MgCl_2溶液中的SCC抗力,但喷丸后材料不得塑性变形或受力超过屈服强度。②喷丸使不锈钢表层产生压应力和组织变化(塑变诱发马氏体、晶粒细化、位错密度增加)。③喷丸可使不锈钢在MgCl_2溶液中的破裂电位变正、阳极电流减小、再钝化能力增强。④喷丸提高不锈钢MgCl_2SCC抗力的主要原因是压应力的作用(其机理是压应力阻抑不锈钢的滑移并促进其再钝化),组织变化的作用较小。
The effects of shot peening on the properties, electrochemical behaviors and surface microstructure of 304C stainless steel were studied respectively by means of chemical, electrochemical and metal physical methods. The mechanism of shot peening to improve SCC resistance of stainless steel was discussed. The following conclusions are obtained: ① Shot peening can improve the SCC resistance of 304L stainless steel in high temperature water and boiling MgCl 2 solution. However, the shot peening material should not plastic deformation or force exceeds the yield strength. ② Shot peening makes the surface of stainless steel produce compressive stress and microstructure changes (martensitic transformation induced by plastic deformation, grain refinement, increased dislocation density). ③ Shot peening stainless steel in the MgCl2 solution rupture potential positive, the anode current decreases, and then passivation enhanced. ④ Shot peening to improve the resistance of stainless steel MgCl_2SCC is mainly due to the role of compressive stress (the mechanism is that compressive stress inhibits stainless steel slip and promote its re-passivation), the role of tissue changes smaller.