MP35N (2.4999) fasteners are known for their extraordinary strength and are the strongest fasteners. MP35N fasteners owe their extraordinary strength to a unique alloy combination of nickel, cobalt, chrome and molybdenum and have ultimate tensile strengths that range from 227 ksi to 294 ksi (with age hardening).
RAYCHIN LIMITED is a leading manufacturer of MP35N Fasteners – precision fasteners engineered from cobalt-nickel-chromium-molybdenum multiphase superalloy, delivering the ultimate combination of ultra-high strength, exceptional corrosion resistance, and reliable performance in the most demanding applications. Our comprehensive range includes MP35N bolts (hex head, socket head, heavy hex), MP35N nuts (hex, heavy hex, lock, slotted), MP35N screws (socket cap, flat head, button head), MP35N washers (flat, lock, spring), MP35N stud bolts (double-end, fully threaded), and MP35N threaded rods. Through precise cold working and age hardening, MP35N achieves ultimate tensile strength exceeding 300 ksi (2070 MPa) while maintaining excellent ductility and toughness. Our portfolio includes all standard and custom configurations manufactured to NAS, AN, MS, ANSI, ASTM, ASME, SAE, API, NACE, ISO, DIN and KS standards. Whether you require MP35N fasteners for medical implants, aerospace critical joints, or downhole drilling tools, RAYCHIN delivers precision, quality, and full traceability. All mechanical properties are presented in MPa and ksi (kilopound per square inch).
MP35N Fasteners – Complete Range of Types & Configurations
MP35N Bolts
MP35N bolts available in hex head (finished hex, heavy hex), socket head cap (ASME B18.3, DIN 912), and flange head configurations. Sizes #2 to 1½" (M2 to M36). UNC, UNF, UNJF-3A, metric threads. Full thread or partial thread options. Conform to AMS 5845 for solution treated, cold worked and aged condition with minimum tensile strength 260 ksi (1790 MPa). Ideal for medical implants, aerospace structural joints, and high-performance applications.
MP35N Nuts
MP35N nuts include hex nuts, heavy hex nuts, jam nuts, lock nuts (all-metal prevailing torque), slotted nuts, and castle nuts. Sizes #2 to 1½" (M2 to M36). Conform to ASME B18.2.2, DIN 934, ISO 4032. Available in solution annealed or age-hardened condition. Nuts are precision tapped to ensure Class 2B/3B fit with mating bolts. Ideal for critical fastening in medical and aerospace applications.
MP35N Screws
MP35N screws include socket head cap screws, flat head screws (82°/100°), button head screws, and set screws (cup point, flat point). Precision rolled threads. Sizes #0 to 1" (M1.6 to M24). Conform to DIN 912, ISO 4762, ASME B18.3. Used in applications requiring the highest strength-to-weight ratio and corrosion resistance, including medical bone screws and aerospace fasteners.
MP35N Washers
MP35N washers include flat washers (ANSI B18.22.1, DIN 125, ISO 7089), split lock washers (ASME B18.21.1, DIN 127), and spring washers (Belleville, curved). Sizes #2 to 1½" (M2 to M36). Custom stampings available. Provide load distribution and locking capability in extreme environments.
MP35N Stud Bolts
MP35N stud bolts (double-end and fully threaded) with equal or unequal thread lengths. Conform to AMS 5845, API 20F. Available with two heavy hex nuts. Sizes #4 to 1½" (M3 to M36). NACE MR0175 compliant for sour service. Ideal for flanged connections in downhole tools and subsea equipment operating up to 600°F (315°C).
MP35N Threaded Rods
MP35N threaded rods (fully threaded continuous rod) available in standard lengths up to 3m (10ft) or custom cut-to-length. Sizes #4 to 1" (M3 to M24). UNC, UNF, metric threads. Precision rolled threads for superior fatigue life. Ideal for custom fastening solutions in medical, aerospace, and corrosive environments.
Manufacturing Standards for MP35N Fasteners
RAYCHIN LIMITED manufactures MP35N fasteners to the following national and international standards, ensuring full compliance for projects worldwide. Both standard and non-standard custom configurations are available.
MP35N Fastener Styles
MP35N Screws
12 Point Screws Button Head Cap Screws Flat Head Screws Hex Head Cap Screws Pan Head Screws Security Screws Set Screws Socket Head Cap Screws Vented Screws
• DIN 603 / ISO 8677 • DIN 912 / ISO 4762 • DIN 913 / ISO 4026 • DIN 914 / ISO 4027 • DIN 915 / ISO 4028 • DIN 916 / ISO 4029 • DIN 921 • DIN 931 / ISO 4014 • DIN 933 / ISO 4017 • DIN 961 / ISO 8676 • DIN 965 / ISO 7046 • DIN 966 / ISO 7047 • DIN 7991 / ISO 10642 • DIN 7380 / ISO 7380 • DIN 84 / ISO 1207 • DIN 85 / ISO 1580 • DIN 34822 • DIN 34821 • DIN 7504 / ISO 15480 • DIN 7984 • DIN 963 / ISO 2009
MP35N Bolts
Hex Head Bolts Shoulder Bolts Wedge Anchor Bolts
• DIN 931 • DIN 933 • ISO 4014 • ISO 4017 • ISO 7370
MP35N Nuts
Hex Nuts Lock Nuts
• DIN 439 / ISO 4035 • DIN 934 / ISO 4032 • DIN 985 / ISO 7040 • DIN 986 • DIN 980 / ISO 7042 / ISO 19513 • DIN 6923 / ISO 4161
MP35N Studs/Rod
Studs Threaded Rod Weld Studs
• DIN 975 • DIN 976
MP35N Washers
Flat Washers Lock Washer
• DIN 125 / ISO 7089 / ISO 7090 • DIN 126 / ISO 7091 • DIN 127 / ISO 7090 • DIN 9021 / ISO 7093
MP35N Hose Clamps
Medium Duty Hose Clamps
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MP35N Screws
12 Point Screws
MP35N 12 point screws allow for higher torque to be applied than a socket head cap screw or head head bolt, however they are be less economical due to the complex head design. Available in 1/4" or larger sizes.
• IFI-115 • MIL SPEC • DIN 34822 • DIN 34821
Button Head Cap Screws
MP35N button head screws offer a wide clamping area and low profile. They are best for fastening material that is too thin to counter bore.
• ASME B18.3 • ASME 18.3.4M • DIN 7380 / ISO 7380
Flat Head Screws
MP35N flat head screws are most commonly offered in an 82° countersink angle, but can be customized to other angles from 60° -120° and are designed to be flush with the surface. Available in slotted and socket drivers. Phillips, 6-lobe, torx and tamperproof drivers in Inconel flat head screws can be made require special manufacturing.
• ASME B18.3 • ASME B18.3.6 • DIN 963 / ISO 2009 • DIN 965 / ISO 7046 • DIN 7991 / ISO 10642
Hex Head Cap Screws
MP35N hex head cap screws offer the added washer face to the bolt head which is lacking on a hex bolt and tighter dimensional tolerances. Ideal for a high clamping force applications with ease of access. Generally availabe in #2 - 1/2" sizes and metric sizes.
• ASME B18.6.3 • DIN 931 / ISO 4014 • DIN 933 / ISO 4017 • DIN 961 / ISO 8676
Pan Head Screws
MP35N pan head screws offer a rounded top are best used for small diameter faster needs. Offered in slotted and they are ideal for low torque applications.
• ASME B18.6.3 • DIN 7985 • DIN 921 • DIN 85 / ISO 1580 • DIN 84 / ISO 1207 (cheese head) • DIN 966 / ISO 7047 (raised counter sunk)
Security Screws
Unique driver designs offer these MP35N screws resistance to unwanted tampering or removal due to the fact that they cannot be removed using an ordinary driver. Inconel security screws are available in several different drive styles, as well as custom per print.
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Set Screws
MP35N set screws are available in cup, cone, flat, dog and half-dog points. Set screws have no head and are equiped with a socket or slotted driver at one end.
• ASME B18.3 • DIN 913 / ISO 4026 • DIN 914 / ISO 4027 • DIN 915 / ISO 4028 • DIN 916 / ISO 4029
Socket Head Cap Screws
MP35N socket head cap screws are ideal for limited access situations where there is little clearance around the screws. They offer a safe, reliable and economic solution.
• ASMET B18.3 • DIN 912 / ISO 4762 • DIN 7984
Vented Screws
MP35N vented screws are best for vacuum environments because the hole drilled through its axis (from head through threads) allow gases and other contaminents to vent. Inconel vented screws are available in any style.
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MP35N Bolts
Hex Head Bolts
MP35N hex bolts are similar to hex head cap screws but without the added washer face. They are ideal for high clamping force applications with ease access.
• ASME B18.2.1 • DIN 931 / ISO 4014 • DIN 933 / ISO 4017
Shoulder Bolts
MP35N shoulder bolts are made up of a head, shoulder and threaded segment. The smooth shoulder section allows for rotating parts. Typically available with socket drivers.
• ASME • DIN 7379 / ISO 7379 • ISO 7370
Wedge Anchor Bolts
MP35N wedge anchor bolts offer a safe secure fastening solution for attaching equipment and other materials to concrete in corrosive environments.
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MP35N Nuts
Hex Nuts
MP35N hex nuts are available in a variety of styles including finished hex nuts, jam nuts and heavy hex nuts.
• ASME B18.16.3 • ASME B18.2.2 • DIN 439 / ISO 4035 • DIN 934 / ISO 4032 • DIN 986
Lock Nuts
MP35N lock nuts are available in all metal and polymer insert styles. All-metal lock provide even load distribution and can be used at high temperatures. Polymer insert styles are more economical and are best for temperatures under than 350°F.
• ASME B18.16.3M • DIN 980 / ISO 7042 / ISO 19513 • DIN 6923 / ISO 4161 • DIN 985 / ISO 10511 / ISO 7040
MP35N Studs & Threaded Rod
Studs
MP35N studs are fully threaded or partially threaded and made to custom lengths.
• ASME B18.31.2 • DIN 976
Threaded Rod
MP35N threaded rod or all thread are available in lengths greater than 1 foot. Minimum order quantity is a total of 6 feet of length.
• ASME B1.1 • DIN 975
Weld Studs
MP35N weld studs are available in both arc or capacitor discharge (CD) styles. Weld studs provide an extremely secure fastening solution when one side of the stud needs to be permanently fix to a part and the other side with the threads accessible.
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MP35N Washers
Flat Washers
MP35N washers are most commonly offered in SAE sizes, but also availabe in USS, oversized and custom sizes upon request.
• ASME 18.21.1 • SAE / USS • DIN 125 / ISO 7089 / ISO 7090 • DIN 126 / ISO 7091
Lock Washers
MP35N lock washers are offered as split lock washers. Belleville spring lock washers can also be made upon request.
• ASME B18.21.1 • DIN 127 / ISO 7090 • DIN 6796 / ISO 10690
Critical Applications of MP35N Fasteners
Medical & Surgical Implants
MP35N fasteners are extensively used in orthopedic trauma implants (bone screws, spinal rods, fracture plates), cardiovascular devices (stent delivery systems, heart valve components), dental implants, and surgical instruments. Full biocompatibility per ASTM F562 and ISO 5832-6, excellent fatigue resistance for long-term cyclic loading, and non-magnetic properties for MRI compatibility.
Aerospace & Defense
MP35N fasteners used in jet engine components, airframe structures, landing gear assemblies, helicopter rotor hubs, and space systems. Withstand operating temperatures up to 600°F (315°C) with exceptional corrosion resistance and fatigue strength. High strength-to-weight ratio for weight-sensitive applications.
Oil & Gas / Downhole Tools
MP35N fasteners qualified per NACE MR0175 for downhole drilling tools, Measurement-While-Drilling (MWD) equipment, wellhead components, subsea actuators, and completion equipment. Resist sulfide stress cracking (SSC) and pitting in H₂S/CO₂ environments at elevated pressures and temperatures. Non-magnetic properties essential for directional drilling instrumentation.
Marine & Subsea
MP35N fasteners in seawater pump couplings, subsea connectors, ROV systems, and offshore platform splash zone components resist pitting and crevice corrosion in saltwater. Virtually immune to seawater stress corrosion cracking and pitting even at the highest strength levels.
Power Generation
MP35N fasteners in gas turbines, steam turbines, and nuclear power systems provide reliable fastening of casings, flanges, and support structures. Maintain clamping force after thousands of thermal cycles from cryogenic to 600°F without relaxation.
High-Performance Springs & Instrumentation
MP35N fasteners used in torsion bars, seals, non-magnetic electrical components, and instrument parts in aerospace and high-pulse magnet research applications where non-magnetic properties are critical.
International Standards & Global Designations – MP35N Fasteners
RAYCHIN LIMITED manufactures MP35N fasteners from material conforming to the most widely used national and international specifications. All material is traceable to the mill.
Designation
Standard / Specification
Description
UNS R30035
Unified Numbering System
Standard designation for MP35N alloy chemistry
AMS 5758
Aerospace Material Specification
Bar, rod, wire; solution heat treated (1900-1925°F, 4-8h, quench)
AMS 5844
Aerospace Material Specification
Bar, rod, wire; solution heat treated and work strengthened (cold worked)
AMS 5845
Aerospace Material Specification
Bar, rod, wire; solution heat treated, work strengthened, and aged (1000-1200°F, 4h) – full condition for maximum strength
ASTM F562
Standard Specification
Wrought nickel-cobalt alloy bar for surgical implants
ISO 5832-6
International Standard
Surgical implant applications
NACE MR0175 / ISO 15156-3
NACE International
Petroleum and natural gas industries – materials for use in H₂S environments
NACE MR0103
NACE International
Materials for use in sour service in refining environments
UNS R30035AMS 5758AMS 5844AMS 5845ASTM F562ISO 5832-6NACE MR0175API 20F
Chemical Composition (Weight %) – MP35N Alloy for Fasteners
Our MP35N fasteners are produced from vacuum induction melted (VIM) and electroslag remelted (ESR) material conforming to the following limits per AMS, ASTM, and industry standards.
Element
Min %
Max %
Typical
Cobalt (Co)
Balance
Balance
~35.0
Nickel (Ni)
33.0
37.0
35.0
Chromium (Cr)
19.0
21.0
20.0
Molybdenum (Mo)
9.0
10.5
9.8
Titanium (Ti)
—
1.0
0.5
Iron (Fe)
—
1.0
0.5
Manganese (Mn)
—
0.15
0.10
Silicon (Si)
—
0.15
0.10
Carbon (C)
—
0.025
0.015
Sulfur (S)
—
0.010
0.005
Phosphorus (P)
—
0.015
0.008
Boron (B)
—
0.010
0.005
Metallurgical note: MP35N is a multiphase cobalt-nickel-chromium-molybdenum alloy strengthened through a unique combination of solid solution strengthening, cold work hardening, and age hardening via precipitation of Co₃Mo phase. The alloy maintains excellent ductility even at 50-70% cold reduction, enabling production of high-strength fasteners with complex geometries. It remains essentially non-magnetic (permeability <1.005 μ) even after extensive cold working.
MP35N fasteners are supplied in various conditions per AMS and ASTM specifications. Data represent typical values based on AMS, ASTM, and industry standards. ksi values (kilopound per square inch) are provided alongside MPa.
Mechanical Properties by Condition – MP35N Fasteners
Condition / Specification
Tensile Strength (MPa)
Tensile Strength (ksi)
Yield Strength 0.2% (MPa)
Yield Strength 0.2% (ksi)
Elongation (%)
Hardness
Annealed (AMS 5758)
896
130
379
55
65
90 HRB
Solution Treated + Cold Worked (AMS 5844)
1758
255
1551
225
12
45 HRC
Cold Worked + Aged (AMS 5845)
1790-2070
260-300
1585-1790
230-260
8-10
51-55 HRC
Spring Temper + Aged
1655-2206
240-320
—
—
—
—
NACE MR0175 (Cold Drawn + Aged)
1517
220
1448
210
10
51 HRC max
Physical Properties – MP35N Alloy
Property
Metric
Imperial
Notes
Density
8.43 g/cm³
0.304 lb/in³
Melting Range
1315-1440°C
2400-2625°F
Elastic Modulus (E) at 20°C
233-234 GPa
33.8 x 10³ ksi
Shear Modulus (G) at 20°C
80.7-83.4 GPa
11.7-12.1 x 10³ ksi
Poisson's Ratio
0.375
0.375
Thermal Expansion (20-300°C)
14.8 µm/m°C
8.2 µin/in°F
Thermal Conductivity
11.2 W/m·K
78 Btu·in/(hr·ft²·°F)
Electrical Resistivity
103 µΩ·cm
40.6 µΩ·in
Magnetic Permeability
<1.005
<1.005
Non-magnetic
High‑Temperature Performance of MP35N Fasteners
MP35N alloy retains useful mechanical properties at elevated temperatures up to 600°F (315°C), making MP35N fasteners suitable for aerospace and oil & gas applications. The alloy can operate at cryogenic temperatures without embrittlement.
Elevated Temperature Capabilities
Property
Value
Notes
Maximum Service Temperature (continuous)
315-427°C (600-800°F)
Depends on condition and application
Short-term Use Temperature
Exceeds 800°F (427°C)
Suitable for short-term exposure
Yield Strength at 400°C
~75% retention
Relative to room temperature strength
Cryogenic Performance
Excellent
No embrittlement down to -300°F (-184°C)
High-Temperature Comparison with Competing Alloys
Alloy
Maximum Service Temperature
Strength Retention at 600°F
MP35N
600-800°F (315-427°C)
Excellent corrosion resistance maintained
MP159
1100-1200°F (593-650°C)
Higher temperature capability
Inconel 718
1300°F (704°C)
Superior high-temperature strength
Note: For applications above 800°F (427°C), consider nickel-based superalloys like Inconel 718 or MP159. MP35N excels in applications requiring maximum strength at moderate temperatures with exceptional corrosion resistance.
Exceptional Corrosion Resistance of MP35N Fasteners
MP35N alloy offers outstanding corrosion resistance across a wide range of aggressive environments, making it suitable for the most demanding applications.
General Corrosion Resistance: Excellent resistance to most mineral acids (nitric, hydrochloric, sulfuric), hydrogen sulfide, and seawater environments.
Stress Corrosion Cracking (SCC): Exceptional resistance to chloride and sour (H₂S) environments. Qualified per NACE MR0175 for oil & gas applications with hardness up to 51 HRC.
Pitting and Crevice Corrosion: Superior resistance to localized corrosion in seawater and brine solutions. Virtually immune to crevice corrosion and pitting even at the highest strength levels.
Hydrogen Embrittlement: Excellent resistance to hydrogen embrittlement even at high strength levels.
Seawater Performance: In seawater, MP35N is virtually immune to crevice corrosion, stress corrosion cracking, and pitting.
Bimetallic Corrosion: Can be safely connected to 400 series stainless steel, 300 series stainless steel, titanium and titanium alloys, copper alloys, and other materials with appropriate precautions.
High-Temperature Oxidation: Forms protective oxide scale at elevated temperatures, maintaining integrity up to 600°F service.
Corrosion Performance Ratings
Environment
Performance
Notes
Seawater
Excellent
Virtually immune to pitting and SCC
Hydrogen Sulfide (H₂S)
Excellent
NACE MR0175 compliant
Hydrochloric Acid
Good
Resistant at moderate concentrations
Sulfuric Acid
Good
Resistant at moderate concentrations
Chloride Solutions
Excellent
Immune to chloride SCC
Manufacturing Standards – MP35N Fasteners
All MP35N fasteners are manufactured and tested to meet the following standards:
We offer surface finishes: passivation (ASTM A967), silver plating (AMS 2410 for anti‑seize), PTFE coating, electropolish. Full traceability and destructive/non‑destructive testing available (UT, MPI, PMI). ISO 13485 certified for medical applications with cleanroom packaging available.
Why RAYCHIN LIMITED – The MP35N Fastener Authority
Metallurgical expertise: Decades of experience with cobalt‑nickel superalloys. We ensure precise heat treatment: solution anneal (1900-1925°F), controlled cold work (30-70% reduction), and aging (1000-1200°F) per AMS 5845 schedules. In‑house PMI verifies chemistry of every heat. Our MP35N fasteners achieve 260-300 ksi ultimate tensile strength with full traceability.
Global certifications: ISO 9001, AS9100D, ISO 13485 (medical), PED, API Q1, NADCAP accredited processes. All fasteners supplied with EN 10204 3.1/3.2 certifications, NACE compliance when required.
Precision forming & threading: CNC cold heading and thread rolling ensure consistent geometry, accurate drives, and Class 2A/3A thread fit. 100% inspection available. Proprietary thread rolling in aged condition ensures optimal fatigue performance.
Custom solutions: Special head dimensions, proprietary drives, non‑standard lengths, and tailored packaging. We support urgent delivery and JIT programs. In-house metallurgical laboratory and failure analysis capabilities.
Contact the MP35N fastener experts
Request a quotation for MP35N fasteners, bolts, nuts, screws, washers, stud bolts, threaded rods – any standard (NAS, MS, AN, ANSI, ASTM, ASME, API, NACE, ISO, DIN, KS) – any condition (AMS 5758, 5844, 5845), any quantity. Global delivery. Mechanical data in MPa/ksi available for all products.
