Effect of Surface Shot Peening on Pitting Corrosion Resistance of Alloy 800

The effect of surface shot peening on pitting corrosion resistance of Alloy 800 tube was investigated using electrochemical cyclic polarization curve, FeCl3 immersion and SEM observation. The results showed that the pitting corrosion resistance of the shot peened Alloy 800 tube was lower than that of the un-shot peened Alloy 800 tube. SEM observation found that the pits of Alloy 800 tube before shot peening were bigger in area and shallower in depth than those of Alloy 800 tube after shot peening. The decreased resistance to pitting corrosion of the shot peened Alloy 800 tube was mainly attributed to the reduction of the surface grain size, the residual stress and the increased surface roughness caused by shot peening technology.