Alloy MP35N UNS R30035: Properties and Applications

# Alloy MP35N UNS R30035: Properties and Applications

## Introduction to MP35N Alloy

MP35N, also known as UNS R30035, is a nickel-cobalt-based superalloy renowned for its exceptional combination of strength, toughness, and corrosion resistance. This alloy was originally developed by SPS Technologies (now part of Precision Castparts Corp.) and has since found widespread use in demanding applications across various industries.

## Chemical Composition

The unique properties of MP35N stem from its carefully balanced chemical composition:

– Nickel (Ni): 35%
– Cobalt (Co): 35%
– Chromium (Cr): 20%
– Molybdenum (Mo): 10%
– Trace elements: Titanium, Iron, and others

## Key Properties of MP35N

### Mechanical Properties

MP35N exhibits outstanding mechanical characteristics:

– High tensile strength (up to 300 ksi in cold-worked condition)
– Excellent fatigue resistance
– Good ductility even at high strength levels
– Superior fracture toughness

### Corrosion Resistance

The alloy demonstrates remarkable resistance to:

– Saltwater environments
– Hydrogen sulfide
– Chloride-induced stress corrosion cracking
– Various acids and alkalis

### Other Notable Properties

– Non-magnetic characteristics
– Excellent biocompatibility
– High-temperature stability (up to 600°F/315°C)
– Good wear resistance

## Heat Treatment and Processing

MP35N can be processed through various methods:

– Cold working (primary strengthening mechanism)
– Solution annealing (typically at 1950-2050°F/1066-1121°C)
– Aging treatments (for additional precipitation hardening)

The alloy can be formed into various product forms including wire, bar, sheet, and tubing.

## Applications of MP35N Alloy

### Medical Industry

MP35N has become indispensable in medical applications:

– Implantable devices (pacemaker leads, stents)
– Surgical instruments
– Orthopedic implants
– Dental applications

### Aerospace and Defense

The alloy’s properties make it ideal for:

– Aircraft fasteners
– Landing gear components
– Missile systems
– High-stress structural components

### Oil and Gas Industry

MP35N is widely used in:

– Downhole tools
– Well completion equipment
– Subsea components
– Corrosive environment fasteners

### Other Applications

– Marine hardware
– Chemical processing equipment
– High-performance springs
– Nuclear applications

## Comparison with Similar Alloys

While MP35N shares some characteristics with other high-performance alloys like Inconel 718 or MP159, it offers superior:

– Corrosion resistance in chloride environments
– Strength-to-weight ratio
– Biocompatibility for medical uses

## Conclusion

Alloy MP35N UNS R30035 continues to be a material of choice for engineers facing extreme mechanical and environmental challenges. Its unique combination of properties ensures its ongoing relevance in critical applications where failure is not an option. As technology advances, we can expect to see even more innovative uses for this remarkable superalloy.