inconel 625 (UNS N06625) to superduplex (UNS S32760) welding

[Hollan Petersen]

Indenting to weld inconel 625 to superduplex in material thickness 3mm, could one give me some tips since I know that such a welding is susceptible to brittle fracture.

[wgadmin]

First of all I suggest you perform the welding using GTAW process with ERNiCrMo-3 filler metal. You should maintain a short arc length as well as keep a sharp tungsten by resharpening it periodically. Keep always the hot tip of the filler metal shielded and run argon not only inside but also on the opposite side of the surface that you weld by using a separate hose and tank and using the bigger possible cup to achieve the best argon shielding. Moreover, you should use considerably less heat input than that used for stainless steel welding (about 1/3) and, as a last tip, let the pass cool plenty before proceeding with the next pass (max interpass temperature = 120 Deg. C).