MP159 Nuts
RAYCHIN SPECIALTY METALS FASTENERS: BOLTS, NUTS, SCREWS, WASHERS, STUDS, THREADED RODS, U-BOLT, J-BOLTS
STANDARD AND CUSTOMIZED, SMALL BATCH AND LARGE BATCH, IMPERIAL AND METRIC
Ultra-strength combined with extreme temperature capabilities
Extreme high strength properties up to 275 ksi ultimate tensile.
Maintains superior strength to 1100°F.
Key Benefits
High ultimate tensile strength of 275 ksi and yield strength of 265 ksi (Cold Worked and Age Hardened) combined with excellent ductility and toughness
Similar corrosion resistance compared to MP35N which is usable in mineral acids, hydrogen sulfide, seawater and salt spray environments.
Excellent fatigue resistance and creep strength at elevated temperatures.
Excellent resistance to crevice corrosion, stress corrosion cracking and hydrogen embrittlement.
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RAYCHIN LIMITED
MP159 Nuts · Hex / Lock / Jam / Flange / Coupling Nuts · Inch & MetricMP159 Nuts: Ultra-High Strength Cobalt-Nickel Alloy Nuts for Extreme Temperature Applications
RAYCHIN LIMITED is a leading manufacturer of MP159 Nuts – precision threaded 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 high-temperature bolted joints. Nuts made from MP159 have been developed to provide a solution to high temperature, high strength components, offering strength capabilities similar to other Cobalt Alloys (MP35N) but can be used at much higher temperatures - up to 1100°F (593°C). Our comprehensive nut product line includes hex nuts, lock nuts, jam nuts, flange nuts, coupling nuts, slotted nuts, and heavy-series nuts – all manufactured to the highest precision standards. Through precise cold working (48% reduction) and age hardening, MP159 achieves ultimate tensile strength up to 275 ksi (1895 MPa) while maintaining excellent ductility and toughness. Developed specifically for higher operating temperatures, MP159 surpasses MP35N by 300°F and can be used beyond 1100°F in short term situations. Our portfolio includes all standard and custom configurations manufactured to NAS, AN, MS, ANSI, ASTM, ASME, SAE, API, NACE, ISO, DIN and KS standards, including ASME B18.2.2 (inch hex nuts), ISO 4032 (metric hex nuts), DIN 934, and DIN 985. Whether you require MP159 hex nuts for advanced gas turbine engines, MP159 lock nuts for downhole drilling tools, or MP159 flange nuts for medical devices, RAYCHIN delivers precision, quality, and full traceability. All mechanical properties are presented in MPa and ksi (kilopound per square inch).
MP159 Nuts – Design & Configurations
Hex Nuts & Heavy Hex Nuts
MP159 hex nuts are the most common type for general bolting, designed to match the strength of MP159 bolts, preventing thread stripping under immense loads. Available in finished hex (ASME B18.2.2, ISO 4032) and heavy hex series (ASME B18.2.2, DIN 934). Precision tapped with class 2B/6H threads. Ideal for aerospace structural joints, jet engine assemblies, and power generation applications where high strength and temperature resistance are critical.
Lock Nuts (All-Metal Flexloc & Nylon Insert)
MP159 lock nuts provide prevailing torque to prevent loosening under vibration in high-temperature environments. Available in all-metal flexloc style (segmented collar creates six "locking fingers" that act as a spring) for applications up to 1100°F, and polymer/nylon insert style for lower temperature applications (<350°F) with various high-performance polymers available (Vespel, PVDF, etc.). Both styles available in hexagonal and 12-point configurations, certified to 15 cycles of prevailing torque per military standards.
Jam Nuts & Flange Nuts
MP159 jam nuts (thin height) are used for locking adjustments in confined spaces. MP159 flange nuts feature an integrated flange that distributes load and eliminates washers, with increased bearing area for critical applications. Manufactured to ASME B18.2.2 (jam) and ASME B18.16.6 (flange). Ideal for rotorcraft dynamic systems and heavy-duty industrial machinery where vibration resistance is essential.
Coupling Nuts & Extended Height Nuts
MP159 coupling nuts (long nuts) are used to connect two threaded rods or for tensioning applications in tight spaces. Available in various lengths and diameters. Custom lengths and special end configurations available. Used extensively in downhole oil & gas tools where exposure to high pressure, H₂S, and high temperatures is constant.
Aerospace & Military Standards
Our MP159 nuts meet applicable sections of NAS1802 (hex nuts), NASM 21042 (lock nuts), MS21042, MS21044, MS21045, MS35649, MS35650, and AN315/AN316. Full compliance with AMS 5841 (solution treated), AMS 5842 (work strengthened), and AMS 5843 (full condition - cold worked and aged) for material and heat treatment. Silver plating per AMS 2410 available for anti-galling.
Custom & Non-Standard Nuts
Need a special thread size, non-standard height, proprietary locking feature, or unique drive configuration? RAYCHIN engineers design and produce custom MP159 nuts to your exact specifications – any condition (annealed, cold worked, aged), with full material traceability. Prototype to production volumes supported. In-house metallurgical laboratory and failure analysis capabilities ensure optimal performance for your application.
Critical Applications of MP159 Nuts
Aerospace & Defense
MP159 nuts are extensively used in advanced gas turbine engines, jet propulsion systems, rocket boosters, landing gear assemblies, and airframe structural joints. The alloy's exceptional high-temperature strength (up to 1100°F) ensures reliable performance in turbine sections, while maintaining excellent fatigue resistance under cyclic loading. Non-magnetic properties essential for sensitive instrumentation. GE Aviation specifies MP159 for CF6 and CFM56 engine applications.
Oil & Gas / Downhole Tools
MP159 nuts qualified per NACE MR0175 for downhole drilling tools, MWD/LWD equipment, wellhead connectors, BOP stacks, and subsea trees. Resist sulfide stress cracking (SSC) and pitting in H₂S/CO₂ environments at elevated pressures and temperatures. Lock nuts provide reliable prevailing torque in high-vibration downhole environments, preventing loosening under extreme conditions.
Power Generation
MP159 nuts in gas turbines, steam turbines, and nuclear reactor internals provide reliable fastening of casing bolts, sensor mounts, and control linkages. Maintain clamping force after thousands of thermal cycles from cryogenic to 1100°F without relaxation. Excellent creep strength (>1000 hours at 650°C/300 MPa) and fatigue resistance at elevated temperatures ensure long-term reliability in power generation applications.
Medical & Surgical Implants
MP159 nuts used in surgical instruments, orthopedic external fixators, prosthetic devices, and medical equipment. Full biocompatibility, excellent fatigue resistance for long-term cyclic loading, and non-magnetic for MRI compatibility. Precision threads allow accurate torque control during surgical procedures. Used in prosthetic devices requiring exceptional strength and corrosion resistance in body fluids.
Marine & Subsea
MP159 nuts in seawater pump flanges, subsea connector assemblies, ROV systems, and offshore platform components resist pitting and crevice corrosion in saltwater. Virtually immune to crevice corrosion, stress corrosion cracking, and pitting even at the highest strength levels. Lock nuts provide reliable prevailing torque in marine environments where vibration and corrosion are constant concerns.
Chemical Processing
MP159 nuts in high-pressure reactor flanges, pump casings, and valve bonnets resist most mineral acids, hydrogen sulfide, and chloride solutions. Excellent resistance to oxidizing and reducing atmospheres, making them ideal for chemical processing equipment and pulp & paper machinery. Superior resistance to stress corrosion cracking in aggressive chemical environments ensures long-term reliability.
International Standards & Global Designations – MP159 Nuts
RAYCHIN LIMITED manufactures MP159 nuts from vacuum induction melted (VIM) and vacuum arc remelted (VAR) material conforming to the most widely used national and international specifications. All material is traceable to the mill.
Chemical Composition (Weight %) – MP159 Alloy for Nuts
Our MP159 nuts are produced from vacuum induction melted (VIM) and vacuum arc remelted (VAR) material conforming to the following limits per AMS and industry standards.
Metallurgical note: MP159 is a multiphase cobalt-nickel-chromium-molybdenum alloy strengthened through a unique combination of solid solution strengthening, cold work hardening (typically 48% reduction), and age hardening via precipitation of γ' phase [Ni₃(Al, Ti, Nb)] and ε phase formation. The alloy maintains excellent ductility even at high cold reduction levels, enabling production of high-strength nuts with precision-tapped threads. It remains essentially non-magnetic (permeability ~1.00265) even after extensive cold working, critical for medical and directional drilling applications. MP159 was developed specifically for higher operating temperatures compared to MP35N, with service capability up to 1100°F (593°C) and short-term use up to 1200°F (649°C). Heat treatment per AMS 5843: solution anneal 1040-1055°C (1900-1925°F), 48% cold work, age 650-675°C (1200-1250°F) for 4-4.5 hours. The high chromium (19%) and molybdenum (7%) content promotes formation of a dense Cr₂O₃ protective film, providing exceptional hot corrosion resistance.
Complete Mechanical & Physical Properties – MP159 Nuts (MPa / ksi)
MP159 nuts are supplied in various conditions per AMS specifications. Data represent typical values based on AMS and industry standards. ksi values (kilopound per square inch) are provided alongside MPa.
Mechanical Properties by Condition – MP159 Nuts
Physical Properties – MP159 Alloy
High‑Temperature Performance of MP159 Nuts
MP159 alloy was developed specifically to meet the need for a fastener alloy that could perform under the higher operating temperatures required for turbine engines and other high performance motors. It has advantages similar to MP35N but can perform in applications up to 593°C (1100°F) and is suitable for short term use at even higher temperatures (up to 649°C/1200°F). The high chromium content (19%) promotes formation of a dense, protective Cr₂O₃ film that provides excellent hot corrosion resistance in aggressive environments.
Elevated Temperature Capabilities
High-Temperature Comparison – MP159 vs. MP35N
Note: MP159 fills the critical gap between MP35N and higher-temperature alloys like Inconel 718, offering superior strength up to 1100°F with excellent corrosion resistance.
Exceptional Corrosion Resistance of MP159 Nuts
MP159 alloy offers outstanding corrosion resistance across a wide range of aggressive environments, making it suitable for the most demanding applications including medical implants, downhole tools, marine equipment, and chemical processing.
- General Corrosion Resistance: Similar corrosion resistance to MP35N, excellent resistance to most mineral acids, hydrogen sulfide, seawater and salt spray environments.
- Stress Corrosion Cracking (SCC): Exceptional resistance to chloride and sour (H₂S) environments. Qualified per NACE MR0175 for oil & gas applications.
- Pitting and Crevice Corrosion: Superior resistance to localized corrosion in seawater and brine solutions due to high chromium (19%) and molybdenum (7%) content. Virtually immune to crevice corrosion and pitting even at the highest strength levels.
- Hydrogen Embrittlement: Excellent resistance to hydrogen embrittlement when properly heat treated.
- Hot Corrosion Resistance: Superior hot corrosion resistance at elevated temperatures due to formation of dense Cr₂O₃ protective film, promoted by high Cr content and the presence of Nb.
- Oxidation Resistance: In 900°C air, oxidation rate <0.1 mm/year, superior to many competing alloys.
- Seawater Performance: In seawater, MP159 is virtually immune to crevice corrosion, stress corrosion cracking, and pitting.
- Biocompatibility: Fully biocompatible for medical implant applications.
- Bimetallic Corrosion: Can be safely connected to stainless steels, titanium alloys, and other corrosion-resistant alloys with appropriate precautions.
Manufacturing Standards – MP159 Nuts
All MP159 nuts 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 MP159 Nut Authority
Contact the MP159 nut experts
Request a quotation for MP159 hex nuts, lock nuts, jam nuts, flange nuts, coupling nuts – any standard (ASME, ISO, DIN, NAS) – any condition (AMS 5841, 5842, 5843), any quantity. Global delivery. Mechanical data in MPa/ksi available for all products.
sales@ray-chin.com | +86 534 2166 566Our team provides technical support in English, German, Mandarin, Japanese.
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