Super Nickel Alloy Castings

Nickel alloys often take over from the stainless and heat resistant steels for the more arduous service conditions.

Alloy 825, a stabilised Ni-Cr-Fe-Mo-Cu alloy, provides a cost effective material having high resistance to oxidising conditions and outstanding resistances to stress-corrosion-cracking.

The Hastelloy™ C range (Ni-Cr-Mo), in particular the C-276 and C-22 grades are resistant to a wide range of oxidising and reducing environments. They are particularly resistant to strong oxidisers, e.g. ferric and cupric chlorides, hot-contaminated mineral acids, solvents, chlorine and chloride contaminated media. The alloy also has excellent resistance to localised forms of attack and stress corrosion cracking.

The Hastelloy™ B range (Ni-Mo) were developed for applications in aggressive reducing environments. It is well suited for applications in handling hydrogen chloride gas and hydrochloric, sulphuric, acetic and phosphoric acids.

Nickel Alloy 625:

Alloy 625 (developed as a Ni-Cr-Mo-Nb Inconel™ alloy) is a versatile super nickel alloy which combines excellent corrosion resistance and elevated temperature properties.

The combination of nickel and chromium provides resistance to oxidising chemicals while the high nickel and molybdenum contents confers resistance to reducing environments. The very high molybdenum content makes alloy 625 one of the most resistant alloys to pitting in chlorides (even in oxidising acids, such as hydrochloric which is totally destructive to stainless steels) and to crevice corrosion.

Alloy 625 is free from chloride-ion stress-corrosion cracking and highly resistant to caustic stress-corrosion cracking. The structure of 625 means that it can be put into service at temperatures from cryogenic to 1100°C. The good resistance to oxidation and scaling, combined with good elevated temperature tensile and creep properties makes 625 an obvious choice for many arduous applications.

The Goodwin use of AOD refining and sophisticated heat treatment results in optimum performance from this alloy.