Bar and Rod
Plate and Sheet
Strip
Pipe and Tube
Wire
Welding
Powder Material
Cast Products
Forged Products
Fittings
Fastening
Round Bar:
φ2–500 mm, 1–6 m length
Flat/Square Bar:
4–100 mm thickness/width
Hex Bar:
A/F 3–100 mm
Hollow Bar:
OD 20–300 mm
Sheet:
0.3–6 mm thickness
Medium Plate:
6–25 mm thickness
Heavy Plate:
25–100 mm thickness
Standard Strip:
0.05–3 mm thick,
10–600 mm wide
Precision strip:
0.01–0.5 mm thick,
tight tolerance ±0.005 mm
Foil:
0.005–0.1 mm thick
Seamless Tube:
OD 6–450 mm,
WT 1–50 mm,
1–12 m length
Welded Tube:
OD 10–600 mm,
WT 1–20 mm
Capillary Tube:
OD 1–10 mm,
WT 0.1–2 mm
Wire Form:
Cold Drawn Wire,
Bright Wire,
Spring Wire,
Fine Wire,
Ultra-fine Wire
General Diameter:
φ0.1–10 mm
Coil Weight:
50–500 kg,
customizable tolerance
Solid Wire:
φ0.8–4.0 mm
Flux-cored Wire:
φ1.2–4.0 mm
Welding Rod:
φ2.0–5.0 mm
Powder Form:
AM 3D Printing Powder,
Spherical Powder,
Gas-atomized Powder,
Water-atomized Powder
Particle Size:
10–150 μm
Sphericity:
≥90% for AM grade
Cast Ingot:
φ200–800 mm
Precision Casting:
min wall 0.5 mm
Cast Pipe:
OD 100–600 mm,
WT 10–50 mm
Forged Bar:
Φ35–500 mm
Forged Ring:
OD 200–2000 mm
Forging Weight:
1–5000 kg
Fittings Form:
Elbow, Tee, Reducer, Flange, Cap, Outlet, Lap Joint
Size range:
1/2''–24'' (DN15–DN600)
Wall thickness:
Sch10–Sch160, STD, XS, XXS
Pressure Class:
150–2500 LB
Fastening Form:
Bolt, Nut, Screw, Stud, Washer, Pin, Rivet
Metric: M3–M64
Imperial: #4–2.5''
Length: 6–500 mm
MP35N is a non-magnetic nickel–cobalt–chromium–molybdenum multiphase alloy possessing a unique combination of ultra-high tensile strength, good ductility and toughness, and outstanding corrosion resistance. This datasheet presents the material within the trade-name designation system.
It belongs to the "Multiphase" (MP) family. In the annealed condition the structure is face-centred cubic (FCC), similar to austenitic stainless steel; cold working (for example wire drawing with a 30–80% reduction in area) transforms part of the FCC into a hexagonal-close-packed (HCP) phase dispersed as platelets, raising strength dramatically. A subsequent aging treatment then provides additional strengthening — but the alloy responds to aging only if it has first been work-strengthened. By this work-hardening-plus-aging route the alloy reaches tensile strengths of about 260–300 ksi (1793–2068 MPa), with hardness up to 55–60 HRC, while retaining good ductility and toughness.
It resists mineral acids, hydrogen sulphide, seawater and other chloride solutions, and offers exceptional resistance to crevice corrosion, stress-corrosion cracking and hydrogen embrittlement; it can be used at cryogenic temperatures without embrittlement. In the fully work-hardened condition, service temperatures up to ~400 °C (750 °F) are suggested. It is produced by vacuum induction melting followed by vacuum-arc remelting (VIM-VAR). Typical applications include fasteners, springs and torsion bars, seals, non-magnetic electrical and instrument parts, and medical implants and prosthetic/orthodontic devices, across medical, oil-and-gas, aerospace, marine and chemical-processing industries.
Values per manufacturer / ASM data, work-strengthened and aged condition.
| Property | Value | Unit |
|---|---|---|
| Density | 8.43 | g/cm³ |
| Young's modulus (20 °C) | 234 | GPa |
| Coefficient of thermal expansion (20–100 °C) | 12.8 | µm/m·°C |
| Thermal conductivity (20 °C) | ~11.2 | W/m·K |
| Magnetic response | Non-magnetic | — |
| Maximum service temperature | ~400 (750 °F, fully work-hardened) | °C |
| Cryogenic service | No embrittlement | — |
| Melting / processing | VIM + VAR | — |
| Structure | Multiphase: FCC matrix + HCP platelets | — |
Limiting composition per ASTM F562 / AMS 5844 (UNS R30035).
| Element | Symbol | Min % | Max % | Role in Alloy |
|---|---|---|---|---|
| Cobalt | Co | Balance (~35) | — | Base; multiphase FCC/HCP structure |
| Nickel | Ni | 33.0 | 37.0 | Matrix stability (~35) |
| Chromium | Cr | 19.0 | 21.0 | Corrosion resistance (~20) |
| Molybdenum | Mo | 9.0 | 10.5 | Solid-solution strengthening + corrosion (~10) |
| Iron | Fe | — | 1.0 | Residual |
| Titanium | Ti | — | 1.0 | Minor addition |
| Manganese | Mn | — | 0.15 | Deoxidiser |
| Silicon | Si | — | 0.15 | Deoxidiser |
| Carbon | C | — | 0.025 | Very low |
| Phosphorus | P | — | 0.015 | Residual impurity |
| Sulphur | S | — | 0.010 | Residual impurity |
Nominal designation: 35Co-35Ni-20Cr-10Mo. The multiphase (FCC + HCP) structure combined with work hardening and aging gives the ultra-high strength.
Typical room-temperature properties; strength depends strongly on condition (AMS 5758 solution-treated → 5844 work-strengthened → 5845 work-strengthened + aged).
| Property | Value | Condition |
|---|---|---|
| Ultimate tensile strength | ~1793–2068 MPa (260–300 ksi) | Work-strengthened + aged (AMS 5845) |
| Tensile strength (max) | up to ~2068 MPa (300 ksi) | Cold-worked + aged |
| Hardness | up to 55–60 HRC | Cold-worked + aged |
| Ductility / toughness | Good | Retained at high strength |
| Fatigue strength | High | — |
Strength is developed by work hardening (FCC→HCP transformation) plus aging; the alloy responds to aging only if first work-strengthened. It performs without embrittlement at cryogenic temperatures. Values are typical; confirm against the mill test certificate and the relevant AMS condition.
| Environment | Performance | Notes |
|---|---|---|
| Seawater / chlorides | Outstanding | Virtually immune to crevice/pitting even at highest strength |
| Hydrogen sulphide (H₂S) / sour service | Outstanding | Highly resistant to sulphide stress cracking; NACE MR0175 |
| Mineral acids | Very Good | Broad resistance |
| Stress-corrosion cracking | Superb | Even at high strength |
| Hydrogen embrittlement | Superb | Important for high-strength fasteners |
| High-temperature oxidation / sulfidation | Very Good | Exceptional for the alloy class |
| Galvanic | Caution | Very noble — can drive galvanic attack on coupled active metals (carbon steel, 316, K-Monel) |
A multiphase alloy strengthened by work hardening (FCC→HCP transformation) followed by aging; it responds to aging only if first work-strengthened.
Anneal / Solution Treat (AMS 5758) Temperature: 1900–1950 °F (1038–1066 °C), 1–4 h (or 4–8 h per AMS), air cool / quench
Work Strengthening (AMS 5844) Cold or warm work after solution treatment (FCC→HCP transformation)
Aging (AMS 5845) Temperature: 1000–1200 °F (538–649 °C), ~4 h, to increase strength Purpose: precipitation strengthening; effective only after work strengthening.
Maximum strength is obtained in the solution-treated + work-strengthened + aged (AMS 5845) condition.
MP35N can be successfully TIG (GTAW) welded; in general its welding behaviour is similar to Type 304 stainless steel, with similar preparations and precautions. Heat input per pass should be kept low — approximately one-half to two-thirds of the heat input used for maraging steel or Type 304 stainless.
| Process | Applicability | Notes |
|---|---|---|
| GTAW / TIG | Possible | Low heat input per pass; like Type 304 prep |
| Mechanical fastening / threading | Primary use | Fasteners, springs; thread-roll after aging |
Note that welding can affect the work-hardening-plus-aging strengthening. For high-strength fasteners, thread rolling after final heat treatment maximises fatigue strength.
Machining Guidelines
| Parameter | Recommendation |
|---|---|
| Machinability | Difficult in any heat-treated condition; superior to Waspaloy (use Waspaloy-like parameters) |
| Strength / hardness | Very high; rigid setup, sharp carbide tooling, low speeds |
| Work hardening | High; positive rake, ample feed |
| Coolant | Ample flood coolant |
Forming Processes
| Process | Notes |
|---|---|
| Cold / warm work | Integral to strengthening (FCC→HCP transformation) |
| Thread rolling | After aging, to maximise fastener fatigue strength |
| Aging | 1000–1200 °F, only after work strengthening |
| Industry | Typical Components | Key Requirements |
|---|---|---|
| Medical / dental | Implants, structural heart devices, cardiac stents, pacing leads, orthodontic wire | Ultra-high strength + biocompatibility + fatigue (ASTM F562 / ISO 5832-6) |
| Oil and gas | Sour-service fasteners, springs, downhole hardware | H₂S + crevice/SCC resistance (NACE MR0175) |
| Aerospace / defence | High-strength fasteners, springs, torsion bars | Strength + fatigue + non-magnetic |
| Marine | Seawater hardware, fasteners | Seawater crevice/pitting immunity |
| Instruments / electrical | Non-magnetic components, seals | Non-magnetic + strength |
| Product Form | AMS Standard | Condition |
|---|---|---|
| Bar (VIM-VAR) | AMS 5758 | Solution heat treated |
| Bar (VIM-VAR) | AMS 5844 | Solution treated + work strengthened |
| Bar (VIM-VAR) | AMS 5845 | Solution treated + work strengthened + aged |
| Bolts / screws | AMS 7468 | Work strengthened, forged head, roll-threaded after aging |
| Wire | AMS 5844 / 5845-related | Work strengthened (+ aged) |
| Surgical-implant bar and wire | ASTM F562 · ISO 5832-6 · BS 7252-6 | Surgical-implant quality |
Nickel-cobalt multiphase ultra-high-strength alloy. UNS R30035. Listed in NACE MR0175 / ISO 15156-3 and MR0103 (sour service). (MP35N is a registered trademark of SPS Technologies.)
| Grade | Type | Nominal | Strength | Best Used For |
|---|---|---|---|---|
| MP35N | Ni-Co multiphase | Ni35-Co35-Cr20-Mo10 | up to ~2068 MPa | Ultra-high-strength fasteners/implants to 400°C |
| MP159 | Ni-Co multiphase | Co36-Ni25-Cr19-Fe9-Mo7-Ti | up to ~1900 MPa | Multiphase fasteners to 593°C (higher temp) |
| Inconel 718 | Ni-base age-hard. | Ni-Cr-Fe-Nb | ~1240-1400 MPa | Turbine discs/fasteners to 650°C |
| Custom 465 | PH stainless | Fe-Cr-Ni-Ti | ~1750 MPa | High-strength stainless components |
| A-286 | Fe-base age-hard. | Fe-Ni-Cr-Ti | ~1000 MPa | Fasteners to 704°C (lower cost) |
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