Hangbo Alloy Group
Shanghai · Est. 2012
UNS R30035 / W.Nr. 2.4999 — Chemical composition, mechanical properties, temperature limits, corrosion resistance, and applications for engineers and procurement professionals.
MP35N (UNS R30035 / W.Nr. 2.4999) is a multiphase cobalt-nickel-chromium-molybdenum alloy capable of attaining ultra-high strength through work hardening combined with aging. Originally developed for critical aerospace fasteners and springs, MP35N is now widely specified for medical implants, orthopedic devices, and sour-gas oilfield components. Its unique metallurgical structure combines the face-centered-cubic matrix of a cobalt alloy with the precipitation-hardening response of a nickel-base superalloy, delivering tensile strengths exceeding 1790 MPa while retaining excellent ductility and corrosion resistance.
The chemical composition of MP35N is carefully controlled to balance high-temperature strength, corrosion resistance, and fabricability. The primary strengthening and corrosion-resisting elements are tightly specified in applicable aerospace and ASTM standards.
| Element | Min % | Max % |
|---|---|---|
| Cobalt (Co) | Balance | Balance |
| Nickel (Ni) | 33.0 | 37.0 |
| Chromium (Cr) | 19.0 | 21.0 |
| Molybdenum (Mo) | 9.0 | 10.5 |
| Titanium (Ti) | — | 1.0 |
| Iron (Fe) | — | 1.0 |
| Carbon (C) | — | 0.025 |
| Manganese (Mn) | — | 0.15 |
| Silicon (Si) | — | 0.15 |
| Phosphorus (P) | — | 0.015 |
| Sulfur (S) | — | 0.010 |
MP35N exhibits a stable microstructure that retains useful physical properties across a wide temperature range, supporting its use in thermally cyclic and high-temperature applications.
| Property | Value | Unit |
|---|---|---|
| Density | 8.43 | g/cm3 |
| Melting Point | 1399-1440 | °C |
| Specific Heat (21 °C) | 390 | J/kg·K |
| Thermal Conductivity (21 °C) | 11.3 | W/m·K |
| Electrical Resistivity (21 °C) | 1.04 | μΩ·m |
| Modulus of Elasticity (21 °C) | 234 | GPa |
| Mean Coefficient of Thermal Expansion (21-538 °C) | 12.6 | μm/m·°C |
Mechanical properties depend on product form and heat treatment condition. Values below represent typical solution-treated and aged bar or forging stock.
| Property | Value |
|---|---|
| Tensile Strength (cold worked + aged) | 1790-2000 MPa (260-290 ksi) |
| Yield Strength (0.2% offset) | 1650-1860 MPa (240-270 ksi) |
| Elongation in 2 inches | 8-12% |
| Hardness (cold worked + aged) | 48-52 HRC |
| Fatigue Strength (10^7 cycles) | 620-760 MPa |
| Modulus of Elasticity | 234 GPa |
MP35N maintains high strength and creep resistance at elevated temperatures, making it suitable for gas turbine hot-section and aerospace structural components.
| Temperature (°C) | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) |
|---|---|---|---|
| 21 (Room) | 1790 | 1650 | 10 |
| 316 | 1620 | 1480 | 10 |
| 427 | 1480 | 1310 | 11 |
| 538 | 1240 | 1100 | 12 |
| 649 | 930 | 830 | 14 |
MP35N provides reliable corrosion resistance in a range of aggressive environments. Performance is governed by the alloy's chromium, molybdenum, cobalt, and nickel contents and by the protective surface oxides formed during service.
The combination of high strength, temperature capability, and environmental resistance makes MP35N suitable for demanding industrial and aerospace applications:
Hangbo Alloy Group manufactures and supplies MP35N in the following product forms, conforming to ASTM, AMS, and other applicable specifications:
| Standard | Description |
|---|---|
| ASTM F562 | Wrought Cobalt-35Nickel-20Chromium-10Molybdenum Alloy for Surgical Implant Applications |
| AMS 5844 | Bars, Forgings, and Rings, Solution Treated |
| AMS 5845 | Bars, Forgings, and Rings, Cold Worked and Aged |
| DIN 2.4999 | Wrought cobalt-nickel-chromium-molybdenum alloy |
| NACE MR0175 / ISO 15156 | Sour service qualification for oilfield fasteners and components |
MP35N is a multiphase cobalt-nickel-chromium-molybdenum alloy that achieves ultra-high strength through cold work plus aging while maintaining excellent corrosion resistance.
In the cold-worked and aged condition, MP35N typically reaches 1790-2000 MPa (260-290 ksi).
Yes; MP35N conforms to ASTM F562 and is widely used for long-term implantable medical devices such as pacemaker leads and orthopedic hardware.
Approximately 35% cobalt, 35% nickel, 20% chromium, and 10% molybdenum, with tight limits on carbon, iron, silicon, manganese, and titanium.
ASTM F562, AMS 5844, AMS 5845, DIN 2.4999, and NACE MR0175/ISO 15156 for sour service.
Solution treatment around 1065 °C followed by water quench, then cold working and aging at 540-650 °C to develop peak strength.
Welding is generally avoided for ultra-high-strength applications; when necessary, similar-composition filler and controlled thermal cycles are required.
Round wire, precision strip, round bar, rod, and custom fastener stock.
MP35N offers higher strength than 35NLT; Elgiloy has similar cobalt-base chemistry but MP35N is more widely specified for medical implants.
MP35N is a premium alloy; pricing depends on form, temper, diameter, certification, and volume. Contact us for current pricing.
Standard wire and bar are often ex-stock; custom sizes or medical-certified material may require 4-8 weeks with MOQs from 5 kg.
Continuous service is generally limited to about 430 °C; short-term exposure can exceed 540 °C depending on strength requirements.
Hangbo Alloy Group maintains supply channels for MP35N in standard and custom product forms. We provide mill test certificates, third-party inspection reports (SGS, TUV), and custom processing services including cutting, machining, grinding, and surface finishing.
For quotations, material certifications, or technical consultation, contact our sales team or call +86-136-1165-6360. We typically respond within 10 minutes.
Request a quotation for MP35N round bars, tubes, plates, or forgings. We stock standard sizes and accept custom orders.