MP35N Special Fasteners Focus For Subsea & Offshore Oil and Gas Engineering.

MP35N (Ni Co Cr Mo 35 35 20 10)
is a nickel-cobalt base alloy that is often specified in subsea special fastener designs due to its unique combination of properties – ultra high strength, toughness, ductility and outstanding corrosion resistance.

Hague Fasteners’ manufactured critical special fasteners are, by virtue of the alloy, work strengthened and finally aged to obtain strength levels of 260 to 300 ksi (1793-2086 MPa) in its full strength condition. With less cold work reduction, the alloy has the best balance of strength and stress corrosion cracking resistance (SCC) for harsh environments.

Hague’s MP35N custom fasteners resist corrosion in hydrogen sulfide, salt water and other chloride solutions, as well as the mineral acids (nitric, hydrochloric, sulfuric). In addition, all critical manufactured special fasteners exhibit exceptional resistance to crevice corrosion cracking in seawater and other hostile environments hence being a popular choice for high integrity applications in offshore and subsea industries.

HEAT TREATMENT (AGING)
MP35N should be aged at the temperature required to achieve the final properties desired. The amount of cold work in MP35N defines the recommended aging treatments.

For AMS 5844 (full strength/ heavily cold worked) material, the alloy should be aged at 1000°F – 1200°F for 4 hours.

For optimum sulfide SCC resistance, less-heavily cold worked material can be aged at 1300°F or 1350°F for 4 hours or at 1425°F for 6 hours as indicated in NACE MR-0175. The 1425°F aging treatment provides the best sulfide SCC resistance, but at the expense of strength.

Exposure to temperatures much above the recommended aging temperatures may result in a significant (and non-recoverable) loss in strength caused by the reversion of the cold-worked metallurgical structure to the much softer annealed structure.

Hague Fasteners are manufacturing every type of conceivable special fasteners and turned components for use in Downhole pump drive shafts assemblies and associated tooling.
High strength special fasteners for marine components.
Seawater Valve stems and pump shafts in Oil & Gas sector and desalination systems.
Fastener system components – pins, tension bolts, shear bolts, engine bolts, tie rods and all critical high integrity corrosion resistant bolts.
Miniature fasteners and micro screws for Medical applications – bone plates, screws, pins.
Fastener Components for use in Autosport & Aerospace.

SPECIFICATIONS
MP35N
AMS 5758
AMS 5844
AMS 5845
ASTM F562
ASTM F688
NACE MR01-75
ISO 15156