Effect of grain size and its uniformity on corrosion resistance of rolled 316L stainless steel by EBSD and TEM

The electrochemical measurements, Electron Backscattered Diffraction (EBSD), statistical analysis and transmission electron microscope (TEM) were used to study the effects of annealing after 92 % cold rolling on the corrosion behavior of AISI 316 L stainless steel in 3.5 % NaCl solution. The different heat treatment, which are 800℃-3 min, 900℃-3 min, 1000℃-3 min and 1000℃-1 h, have a significant effect on the corrosion resistance of the materials. Except for 800℃-3 min which was not completely recrystallized, the increase of grain size is beneficial to the corrosion resistance, but the uniformity of grains should also be considered. The high energy stress concentration at the grain boundaries and the distribution of intermetallic compounds pose challenges to the stability of passivation film. The final results indicated that the annealing at 1000℃ for 3 min samples with fewer grain boundaries and moderate grain size has the best passivation film quality and excellent corrosion resistance.