Effect of heat-input on pitting corrosion behavior of friction stir welded high nitrogen stainless steel

H.Zhang，P.Xue，D.Wang，L.H.Wu，D.R.Ni，B.L.Xiao，Z.Y.Ma

Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences

摘 要：In this study, different welding parameters were selected to investigate the effects of heat-input on the microstructure and corrosion resistance of the friction stir welded high nitrogen stainless steel joints.The results showed that, the welding speed had major influence on the duration at elevated temperature rather than the peak temperature. The hardness distribution and tensile properties of the nugget zones（NZs） for various joints were very similar while the pitting corrosion behavior of various NZs showed major differences. Large heat-input resulted in the ferrite bands being the pitting location, while tool wear bands were sensitive to pitting corrosion in the low heat-input joints. Cr diffusion and tool wear were the main reasons for pitting. The mechanisms of pitting corrosion in the NZs were analyzed in detail.

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