Probably depends on the environment they are in, but my own field studies (mainly in produced water from oil+gas fields) back up some published information showing that changes in the microstructure and the the morphology of the carbides can influence corrosion rate. Anything that decreases the heterogeneity of the weld zone is likely to have a beneficial effect on corrosion resistance, although the effect may be small. Reducing residual stress is beneficial, but a higher temperature heat treatment that homogenizes or normalizes the microstructure may have additional benefits.