Corrosion resistant alloy (CRA) weld overlay of boilers began in the late 1970’s and early 1980’s when
waste-to-energy (WTE) boilers needed protection. At that point in time, filler metal 625 (ERNiCrMo-3)
was enjoying tremendous popularity. It was only natural that this solid solution “superalloy” be applied
to these WTE boilers. This high nickel alloy performed quite well on WTE waterwall boiler tubes.
However, the performance of WTE superheaters overlaid with alloy 625 was not acceptable.