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316L stainless steel is used as the main material of PWR primary circuit equipmentas its good corrosion resistance.Austenitic stainless steel, however, is sensitive to stress corrosion cracking (SCC) and this kind of problem has almost happenedtmder all the workcondition in the PWR.The microscopic observation methods were used to study the effect of the stress on the corrosion behavior of 316L stainless steel under the environment of high temperature and high pressure water and explore the relationship of its excellent corrosion resistance and its characteristics of organizationstructure.The results showed that 316L stainless steel presentedan equiaxed austenitetype.The continuous carbidesdistributedat grain boundary and the granular carbides scatteredinintragranular.EBSD results showed that 316L stainless steel has Σ3 coherent twin boundary.Compared with stress-free, 316L stainless steelhas relatively lowerpole density, weaker texture and poor mechanical properties under the stress, which lead to the corrosion resistance performances decreasing.The TEM results showed that 316L stainless steel possessed austeniteand skeleton ferrite structure.Deformation induced the rotation of the grain under the stress.Grain rotation changed the grain orientation, and then formed a large deformation twin, which resulted in the texture loosing.