DAIKOWT 622

The composition of the weld deposit, Ni-22Cr-13.5Mo-3W, has been developed to be compatible with the nickel-based alloy more commonly known as alloy C22. The high molybdenum content is comparable to that of alloys C276 and C4; however, performance in a wide range of more oxidizing environments is significantly improved by increasing chromium to 22% in alloy C22. Alloy C22 also offers a robust, niobium-free (Nb) metal deposit for dissimilar welds between superaustenitic and superduplex stainless steels or between these and nickel-based alloys. Some regulations have prohibited or limited the use of alloy 625 consumables for such applications, as harmful Nb-rich precipitates can form in the diluted or partially mixed regions near the edges of the fusion zone. Applications of alloy C22 in highly corrosive environments include scrubbers for flue gas desulfurization (FGD), digesters and equipment for paper production, chemical process plants, corrosion-resistant overlays, as well as offshore environments and the petrochemical sectors. Typically, preheating is not required; it is preferable to maintain an interpass temperature below 100 °C and heat inputs below 1 kJ/mm.