冷加工对316L不锈钢力学行为和组织的影响

Effect of Cold Work on Structure and Mechanical Behavior of 316L Stainless Steel

采用室温拉伸及硬度测试研究了不同的冷变形量对316L不锈钢室温力学性能及硬度的影响,并通过OM、TEM对冷变形后组织结构的观察,分析讨论了不同变形后力学性能及硬度的变化机制。结果表明,冷变形使材料的强度和硬度得到大幅度提高,但塑性有所降低。冷变形量为25%时,钢的屈服强度可达到745MPa,同时伸长率达到19.3%。随冷变形量的不同,该钢加工硬化能力不同。变形量低于2.5%时,强度、硬度增加的速度较快,而变形量高于约2.5%后,强度、硬度增加的速度却相对较小,其原因是变形机制不同。另外,冷变形后钢的屈服强度与硬度有着相似的变化规律,由此提出了由冷变形后硬度变化预测冷变形后拉伸屈服强度的方程。

Investigated the effect of various degrees of plastic deformation introduced by cold roiling at ambient temperature on the tensile properties and hardness of 316L stainless steel by tensile test and hardness test. Microstructural studies were conducted by OM and TEM to clarify the mechanism of the variation of the tensile properties and hardness of 316L stainless steel at different cold rolling reductions. The results indicated that the strength and hardness increased significantly by cold deformation, whereas the ductility of the steel is decreased. When the cold rolling percentage was up to 25%, the yield strength can reach 745 MPa, while elongation can be maintained 19.3%. The capacity of work-hardening vary with the cold rolling percentage. The strength and hardness increased greatly as the plastic deformation was lower than about 2.5 %, whereas the increment speed of strength and hardness are relatively small as the plastic deformation was higher than about 2.5% because of different deformation mechanism. Besides, the yield strength and hardness are found to have similar change rule after cold rolling. And, an excellent predicting equation of yield strength to hardness after cold rolling is presented.