Name: Cobalt MP35N
Brand: Cobalt Alloys

Material Overview

Cobalt MP35N material profile

A concise grade introduction for buyers who need to confirm composition, properties, standards, available forms and suitable applications before sending an inquiry.

Engineering profile

MP35N® is a high-strength cobalt-nickel-chromium-molybdenum alloy combining exceptional tensile strength, toughness, fatigue resistance and corrosion resistance. Its properties are developed through vacuum melting, solution treatment, cold work and controlled aging. MP35N resists sulfide stress cracking, hydrogen embrittlement, seawater corrosion, chloride attack and many mineral acids, making it suitable for oil and gas hardware, aerospace fasteners, springs, medical and dental devices, non-magnetic components, pressure housings and demanding cryogenic applications.

Technical data on this page is for material selection reference. Final acceptance values should be confirmed by the purchase standard, heat treatment condition, product form, size and material test certificate.

Chemical Composition

Cobalt MP35N composition range

The following table shows common limiting composition values for Alloy 625 / UNS N06625. Actual product chemistry is reported by heat on the material test certificate.

Element	Symbol	Typical Requirement, wt.%	Role in MP35N
Cobalt	Co	Balance	Forms the cobalt-nickel matrix and contributes to high strength and toughness.
Nickel	Ni	33.0-37.0	Stabilizes the face-centered-cubic matrix and improves ductility and corrosion resistance.
Chromium	Cr	19.0-21.0	Provides passivation and resistance to chloride and seawater corrosion.
Molybdenum	Mo	9.0-10.5	Provides solid-solution strengthening and resistance to localized corrosion.
Iron	Fe	1.0 max	Controlled residual element.
Titanium	Ti	1.0 max	Controlled minor element affecting precipitation and aging response.
Carbon	C	0.025 max	Restricted impurity for cleanliness, ductility and corrosion performance.
Manganese	Mn	0.15 max	Controlled processing element.
Silicon	Si	0.15 max	Controlled residual element.
Phosphorus	P	0.015 max	Restricted impurity.
Sulfur	S	0.010 max	Restricted impurity for hot workability and corrosion performance.

Physical Properties

Key physical and thermal data

These values help customers compare density, thermal behavior, magnetic response and conductivity during early material selection.

Property	Metric Value	Imperial / Additional Value	Condition
Density	8.42 g/cm3	0.304 lb/in3	Approximately 20 °C
Melting Range	1315-1440 °C	2399-2620 °F	Typical range
Modulus of Elasticity	233 GPa	33.8 x 10³ ksi	Approximately 20 °C
Modulus of Rigidity	83.4 GPa	12.1 x 10³ ksi	Approximately 20 °C
Mean Coefficient of Thermal Expansion	14.8 µm/m·°C	8.2 µin/in·°F	Approximately 20-300 °C
Electrical Resistivity	103 µΩ·cm	40.6 µΩ·in	Approximately 20 °C
Thermal Conductivity	11.2 W/m·°C	78 Btu·in/ft2·h·°F	Approximately 20 °C
Specific Heat	Approximately 500 J/kg·°C	Temperature dependent	Representative room-temperature value
Magnetic Permeability	Low magnetic response	Non-magnetic in typical wrought conditions	Verify for magnetic-sensitive assemblies

Mechanical Properties

Room-temperature mechanical properties

Mechanical properties vary with product form, size, processing route and heat treatment. The table below summarizes commonly referenced nominal values for material selection.

Material Condition	Tensile Strength	Yield Strength, 0.2%	Elongation	Reduction of Area / Hardness
Annealed	827-965 MPa	Approximately 400-620 MPa	Approximately 40-50%	Typical ductile condition
Solution heat treated	793-965 MPa	Approximately 400-620 MPa	Approximately 40-50%	Typical solution condition
Medium-hard, work strengthened	1000 MPa min	655 MPa min	20% min	ISO 5832-6:2022 condition
Hard, work strengthened	1207 MPa min	1000 MPa min	10% min	ISO 5832-6:2022 condition
AMS 5844 solution treated and cold drawn	Approximately 1790 MPa min	Approximately 1586 MPa min	8% min	Typical heavy cold-worked bar condition
AMS 5845 cold drawn and aged	Approximately 1793 MPa min	Approximately 1586 MPa min	8% min	Typical aged bar condition; hardness condition dependent
Spring temper	1517-1931 MPa	Condition dependent	Condition dependent	Cold-worked wire or strip
Spring temper plus aging	1655-2206 MPa	Condition dependent	Condition dependent	Typical 538-649 °C aging for 4 hours
Values are typical or specification-related values, not universal guarantees. Final properties depend on product size, cold reduction, aging temperature, test direction and applicable standard.

For pressure equipment, aerospace parts or project-specific acceptance, use the minimum requirements in the specified ASTM, ASME, AMS, EN or customer drawing rather than nominal values.

Standards & Specifications

Common Cobalt MP35N standards by product form

YSN128 can quote Alloy 625 products according to ASTM, ASME, AMS, EN, DIN, ISO or customer drawing requirements. Certificate scope can be matched to the purchase order.

Product Form / Condition	Common Standard	Scope	Buyer Note
Annealed Bars	AMS 5758	Vacuum induction plus consumable-electrode vacuum remelted bars supplied solution heat treated for work strengthening	Specify diameter, solution treatment and mechanical test requirements.
Work-Strengthened Bars	AMS 5844	Solution heat treated and cold-drawn MP35N bars	Suitable when machining is performed before the final aging treatment.
Cold-Drawn and Aged Bars	AMS 5845	Solution heat treated, cold drawn, aged and centerless-ground bars	Specify final strength, hardness and dimensional condition.
Wrought Surgical Implant Products	ASTM F562	Wrought 35Co-35Ni-20Cr-10Mo alloy for surgical implant applications	Confirm the current revision and the required condition: annealed, medium hard or hard.
Wrought Surgical Implant Products	ISO 5832-6:2022	Wrought cobalt-nickel-chromium-molybdenum alloy	ISO tensile values are condition-specific and finished-product properties may differ.
Sour-Service Applications	NACE MR0175 / ISO 15156-3	Material selection and hardness restrictions for oil and gas environments	Verify environmental limits, hardness and the project qualification route.
Additional Sour-Service Reference	NACE MR0103	Materials guidance for refining and related sour-service environments	Use only when required by the process specification.
Solution Treatment	Approximately 1038-1052 °C for 4-8 hours, air cool	Typical reset treatment before cold working	The exact cycle is controlled by the applicable AMS or customer specification.
Aging	Approximately 538-649 °C for 4 hours, air cool	Age strengthening of cold-worked MP35N	Aging above the recommended range can cause irreversible loss of cold-worked strength.

Available Product Forms

Cobalt MP35N supply range

Review available product forms, size ranges, standards and delivery options for this alloy.

Form	Common Size Range	Delivery Condition	Typical Applications	Page Link
Pipe & Tube	Small and miniature seamless tubing; custom dimensions available	Annealed, solution treated, cold drawn or project specified	Pressure housings, medical devices and high-pressure instrument lines	View Pipe & Tube
Round Bar	Small precision bar through larger custom diameters	Annealed, solution treated, cold drawn or aged	Fasteners, shafts, valve stems, pins and oilfield hardware	View Round Bar
Sheet & Plate	Thin sheet and plate in custom dimensions	Solution treated, cold rolled or project specified	Medical components, non-magnetic structures and specialty hardware	View Sheet & Plate
Strip & Foil	Precision strip and foil in custom widths	Cold rolled, spring temper, aged or annealed	Springs, seals, electrical contacts and miniature devices	View Strip & Foil
Wire	Fine wire through heavy spring and welding-wire sizes	Annealed, cold drawn, spring temper or aged	Springs, torsion bars, cables, medical devices and seals	View Wire
Fasteners	Bolts, nuts, screws, studs, pins and custom threaded parts	AMS 5844, AMS 5845 or customer-specific aged condition	Aerospace, oil and gas, subsea and medical assemblies	View Fasteners
Fittings	Custom connectors, adapters and pressure fittings	Machined from qualified bar or tube stock	High-pressure valves, instrumentation and sour-service systems	View Fittings
Flanges	Custom small-bore and high-pressure flange components	Machined, cold worked or heat treated to project requirements	Pressure housings, subsea equipment and specialty connections	View Flanges
Forgings	Rings, discs, blocks and custom closed-die forgings	Solution treated, cold worked or aged as specified	Valves, actuators, shafts and high-strength aerospace hardware	View Forgings
Welding Wire	Custom filler-wire diameters and straight lengths	Clean, controlled-chemistry wire for qualified procedures	Repair welding, dissimilar joining and specialty fabrication	View Welding Wire

Material Selection Guide

When to consider Cobalt MP35N

This guide helps buyers connect service conditions with the typical advantage of Alloy 625. Final selection should consider medium concentration, temperature, pressure, fabrication, availability and budget.

Alloy / Material	Selection Strength	Typical Position	Selection Note
MP35N	Ultra-high strength, toughness, fatigue resistance and sour-service corrosion resistance	Fasteners, springs, medical devices, subsea and oilfield hardware	Select when very high strength must be combined with non-magnetic behavior and corrosion resistance.
Elgiloy	Excellent spring properties and corrosion resistance at moderate-to-high strength levels	Fine springs, wire components and medical devices	Consider when spring forming and corrosion resistance are more important than MP35N peak strength.
Inconel® 718	High strength with broad aerospace supply and established heat treatment	Aircraft fasteners, turbine components and structural hardware	Compare magnetic response, chloride or sour-service exposure and required temperature range.
HAYNES® 25 / L-605	High-temperature cobalt-base strength and galling resistance	Hot-section, bearing and spring applications	Choose L-605 for elevated-temperature service; choose MP35N for extreme ambient-temperature strength.
CoCrMo-F75	Cast implant-grade corrosion and wear resistance	Orthopedic and dental investment castings	MP35N is the wrought, cold-worked and aged alternative when ultra-high strength is needed.
Ti-6Al-4V	Lower density and lower elastic modulus	Orthopedic implants, aerospace structures and lightweight components	Compare galling, wear pairing, modulus, fatigue, magnetic requirements and corrosion environment.

Why Choose Us

Supply and quality support for Cobalt MP35N

For ranking traffic, buyers need more than a data sheet. This section gives clear trust signals for procurement, engineering and quality teams.

STASTM / ASME / AMS / EN

Quotation can be matched to project standards and product form specifications.

MTEN10204 3.1 MTC

Heat number, chemistry, mechanical properties and inspection records can be supplied.

QCPMI & Inspection

PMI, UT, dimensional inspection, visual inspection and packing check are available.

CSCustom Size

Cutting, machining allowance, rough machining and drawing-based supply can be arranged.

EPExport Packing

Wooden case, bundle, waterproof protection and international shipping documents.

RFFast Technical Reply

Send grade, size, standard, quantity and destination for a practical quotation route.

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FAQ

Cobalt MP35N questions from buyers

Find practical answers about procurement, standards, fabrication and industrial applications.

MP35N is used for aerospace fasteners, oilfield and sour-gas components, subsea hardware, springs, torsion bars, seals, valve parts, pressure housings, medical and dental devices, non-magnetic electrical components and high-strength instrument parts.

Yes. MP35N is commonly identified by UNS R30035 and W.Nr. 2.4999. The registered MP35N trade name refers to the nominal 35Co-35Ni-20Cr-10Mo alloy, but the purchase order must also state the applicable AMS, ASTM, ISO or NACE condition.

MP35N is solution treated, cold worked by drawing, rolling, swaging or related methods, and then aged. Cold work provides substantial dislocation strengthening, while controlled aging produces additional precipitation strengthening. The final cold reduction and aging temperature determine the balance of strength, ductility and corrosion resistance.

A typical solution treatment is approximately 1038-1052 °C for 4-8 hours followed by air cooling. Cold-worked MP35N is commonly aged for approximately 4 hours between 538 and 649 °C. The precise treatment depends on the AMS or customer specification. Excessive temperature can revert the cold-worked structure and cause irreversible strength loss.

AMS 5758 covers solution-treated bar for work strengthening, AMS 5844 covers solution-treated and cold-drawn bar, and AMS 5845 covers cold-drawn and aged bar. ASTM F562 and ISO 5832-6 cover wrought MP35N-type material for surgical implants. NACE MR0175/ISO 15156-3 and NACE MR0103 may apply to specified sour-service applications.

MP35N has excellent resistance to seawater pitting, crevice corrosion, chloride attack, hydrogen embrittlement and sulfide stress cracking. It is widely used in demanding sour-gas and subsea environments, but the actual limit depends on hardness, cold-work level, temperature, stress, exposure chemistry and the governing NACE requirements.

MP35N can be joined only with a carefully qualified procedure. Welding or high heat near a cold-worked section can locally soften the alloy and reduce strength. The welding method, filler, solution treatment, post-weld processing and inspection should be selected for the specific component rather than assumed from annealed MP35N data.

Please send the UNS or MP35N designation, product form, dimensions, quantity, required AMS, ASTM, ISO or NACE standard, cold-work level, aging condition, tensile and hardness targets, magnetic requirements, surface finish, inspection plan and destination. For medical parts, include the applicable implant standard and cleanliness requirements.

Cobalt MP35N