Ductility-Dip Cracking in High Chromium, Ni-Base Filler Metals

Microstructure and flow behavior of Ni–Cr–Fe welds with Nb and Mo additions

“…To improve the DDC resistance, Alloy 52 is modified into Alloy 52M with an addition of 0.5-1.0 wt% Nb. Now Alloy 52MSS is further bettered its DDC resistance with additions of more than 2.5 wt% Nb and 4.0 wt% Mo [8]. It is developed to replace Alloy 52M for repairing the components of nuclear power plants.…”

“…Many studies have demonstrated that Alloy 52 is more susceptible to DDC than Alloy 82 for its high chromium content [8][9][10]. Alloy 82 weld is also reported to have a lower DDC susceptibility because of tortuous grain boundaries and large precipitates resulting from the addition of niobium.…”

“…Hot cracking and ductility dip cracking (DDC) are two technical concerns when welding with these Ni-based alloy filler metals [8].…”

The influence of Nb and Mo on the microstructure and mechanical properties of Ni–Cr–Fe GTAW welds

“…The new alloy is named as Alloy 52M. Now it is believed that DDC could be mitigated when a weld metal has a niobium content more than 2.5 wt% and molybdenum content greater than 4.0 wt% [9]. Alloy 52M has been extensively used to repair the components of nuclear power plants.…”

Solidification behaviour of a high chromium nickel base alloy weld deposited metal

“…4,5 However, unfortunately, as confirmed by industry experience and laboratory investigation, the high chromium nickel base alloys were susceptible to hot cracking during welding. 6,7 To understand the mechanism of cracking and prevent the cracking phenomenon, it was necessary to investigate the solidification behaviour of the weld deposited metal (WDM). However, unlike numerous established alloy systems, such as alloy 718 and alloy 625, there was just a little investigation about the WDM microstructure of high chromium nickel base alloys to date.…”