利用光学显微镜(OM)、电子探针(EPMA)及X射线衍射(XRD), 研究了不同Al含量316L不锈钢热轧态显微组织,测试了其力学性能和抗腐蚀性能. 结果表明: Al含量小于2%时, 基体为γ相, Al含量为4%时,基体转变为α+γ双相组织, Al元素分别以固溶和Al₄C₃沉淀相的形式存在.合金的抗拉强度、屈服强度随着Al含量的增加, 先降低后升高, 塑性略有下降.利用SEM分析合金的断口形貌表明, 其断裂形式均为延性断裂.含2%Al的316L不锈钢具有最低的均匀腐蚀速率和晶间腐蚀速率,基体中Al₂O₃钝化膜的形成及Al₄C₃析出减少了贫Cr区的出现是导致材料耐蚀性提高的主要因素.

316L stainless steel is applied to high-temperature environment because of an attractive combination of mechanical properties and corrosion resistance in various aggressive environment. However, the corrosion resistance of 316L was reduced in a particular environment such as water vapor, aggressive sulfur gas which was attributed to the Cr₂O₃ protective scales formed in 316L. The Cr₂O₃ scales are compromised by water vapor due to the formation of volatile Cr oxy--hydroxide species. The Al₂O₃ is more thermodynamically stable in these enviroment than Cr₂O₃. In this work, the effects of Al element on the microstructure, mechanical properties and corrosion resistance of hot-rolled 316L were investigated. Microstructure evolution was observed by OM, EPMA and XRD. Mechanical properties were measured by tensile tests. The resistances to intergranular and uniform corrosion of hot-rolled 316L with different Al content were investigated by means of soaking method at 65%HNO₃ and  5\%H₂SO₄, respectively. The results show that microstructure has changed from single γ to α+γdouble phase. With the increase of Al content in 316L, the yield strength and ultimate tensile strength increased but the ductility decreased. The fracture morphology of tensile was observed by SEM. Which indicated that the fracture mechanism behaved in ductile fracture. Corrosion rate of intergranular and uniform corrosion decreased remarkly as the Al content increased. The optimum Al content in terms of corrosion rate curve was about 2%. Improvment of corrosion resistance was mainly due to Al₂O₃ scale formed in 316L.