Nickel based alloy castings

Although more expensive than stainless and duplex steels, these materials are necessary for a range of arduous environments which would attack the stainless, iron-based materials.

With 40% nickel and 20% chrome, Alloy 825 offers very high resistance to both oxidizing and non-oxidizing hot acid conditions and outstanding resistance to stress-corrosion cracking. It is resistant to pitting corrosion by all except strongly oxidizing chloride solutions. With approximately 40% iron content, its material cost lies between that of duplex and the other main nickel based alloys.

Hastelloy C type alloys (15% chrome, 15% molybdenum, nickel based) gives outstanding corrosion resistance in both reducing and oxidizing media. It is widely used in the severest environments encountered in chemical processing, pollution control, pulp and paper production and other fields.

Hastelloy B type alloys (30% molybdenum, nickel based) were developed particularly for resistance to hot concentrated hydrochloric acid solutions and hydrogen chloride, particularly reducing conditions.

Alloy 625 (20% chrome, 9% molybdenum, nickel) has high fatigue and creep strength and excellent corrosion resistance. It is highly resistant to chloride ion stress corrosion cracking. It finds use in pumps and valves for handling acids at elevated temperatures in the food, chemical, mining and petrochemical industries.

Monel alloys (70% nickel, 30% copper) show good resistance to attack in reducing environments. It is widely used in handling sulphuric, hydrochloric and organic acids in the marine, plastics, steel and food processing industries.