Arcos 617 description: Arcos 617 is designed to weld nickel-chromium-molybdenum base material, as well as for joining various dissimilar high temperature alloys. It is designed for TIG, MIG and submerged arc welding. The weld metal provides excellent strength and oxidation resistance above 1,500˚F. Arcos 617 can also be used for overlay welding where a similar chemistry is desired.