The attractive properties of MP35N have led to its adoption into critical equipment in industries including aerospace, medicine, mining, offshore equipment, and oil and gas production. 

 

Even at yield strengths exceeding 200 ksi (1380 MPa), MP35N possesses excellent corrosion resistance in harsh oil and gas environments including seawater, chloride brines, sweet gas, and sour gas.

 

It is the highest strength alloy approved in NACE MR0175 [1] for use in unrestricted sour service, offering an unmatched combination of strength and corrosion resistance.

The unique capabilities of MP35N are derived from the alloy’s chemistry, premium melting technology, cold-working, and heat treatment. MP35N (UNS R30035) is a vacuum induction melted (VIM), vacuum arc re-melted (VAR) superalloy with cobalt, nickel, chromium, and molybdenum as its primary alloying elements. Its nominal chemical composition by weight is 35% cobalt, 35% nickel, 20% chromium, and 10% molybdenum. The VIM VAR melt practice provides superior cleanliness and reduces the presence of non-metallic inclusions and residual elements, like carbon, that have deleterious effects on mechanical properties and corrosion resistance.

 

MP35N is unique in its ability to be simultaneously strong, tough, and ductile with superior corrosion resistance. It can be strengthened beyond the capabilities of stainless steels and nickel-based alloys like 718 with equal or better corrosion resistance in many environments.

The high strength of MP35N is created by a combination of work hardening and an age hardening heat treatment. Yield strength in the high-strength cold-worked-and-aged condition can exceed 260 ksi (1793 MPa) with ductility near 40% reduction of area. Much of the strengthening occurs during cold working, and the annealed properties are like many stainless steels. Typical properties in the annealed condition are 150 ksi ultimate tensile strength, 60 ksi yield strength, 68% elongation, and 75% reduction or area.