Influence of Creq/Nieq on pitting corrosion resistance and mechanical properties of UNS S32304 duplex stainless steel welded joints

Pitting corrosion resistance and mechanical properties of 2304 duplex stainless steel with different Creq/Nieq values after plasma-arc welding and welding thermal simulation were systematically studied. The results showed that the lower the Creq/Nieq value in the experimental range, the better the microstructure after welding or welding thermal cycle. High pitting resistance equivalent number in the chemical composition brought in low weight loss rate and high critical pitting temperature for base metal. Furthermore, as the Creq/Nieq value decreased, the degradation of pitting corrosion resistance after welding thermal cycle reduced.

► Influence of Creq/Nieq on properties of DSS UNS S32304 was studied firstly.
► Both simulated HAZ and practical PAW welded joints were investigated and compared.
► Both chemical and electrochemical methods were applied.
► The lower Creq/Nieq, the better microstructure and pitting corrosion resistance.