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MP159 Shoulder Bolts

MP159 Shoulder Bolts As aerospace engineering advances, so must the materials to meet the technological requirements of this industry. Shoulder Bolts made from MP159 have been developed to provide a solution to high temperature, high strength components. MP159 Shoulder Bolts offer strength capabilities similar to other Cobalt Alloys (MP35N) but can be used at much higher temperatures - up to 1100°F, compared to MP35N’s usable limit of 800F. In addition, MP159, can be used beyond 1100°F in short term situations.

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

Name: MP159 Shoulder Bolts
SKU: 0

MP159 Shoulder Bolts · Precision Shoulder Screws · Stripper Bolts · Inch & Metric · AMS 5841 / 5842 / 5843

MP159 Shoulder Bolts: Ultra-High Strength Cobalt-Nickel Alloy Shoulder Screws for Precision Locating & High Shear Applications

MP159 (UNS R30159) | AMS 5841 / 5842 / 5843 | ASTM F | Co-Ni-Cr-Mo Multiphase Alloy

RAYCHIN LIMITED is a leading manufacturer of MP159 Shoulder Bolts – 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 bolted joints. Shoulder bolts (also known as shoulder screws or stripper bolts) feature a precision ground shoulder that acts as a bearing surface or shaft, with a threaded section of reduced diameter. They are critical components for locating parts, mounting stripper plates, and acting as pivot pins in machinery and tooling. Through precise cold working and age hardening, MP159 achieves ultimate tensile strength in excess of 1830 MPa (265 ksi) while maintaining excellent ductility and toughness. Developed specifically for higher operating temperatures, MP159 can perform in applications up to 593°C (1100°F), surpassing the capabilities of MP35N. 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 B18.3 (inch shoulder screws) and ISO 7378 (metric shoulder screws). Whether you require MP159 shoulder bolts for aerospace landing gear, downhole drilling tools, or medical devices, RAYCHIN delivers precision, quality, and full traceability. All mechanical properties are presented in MPa and ksi (kilopound per square inch).

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MP159 Shoulder Bolts – Design & Configurations

Precision Ground Shoulder

MP159 shoulder bolts feature a precision ground shoulder with tight diameter tolerances (typically h6 or h7). The shoulder acts as a bearing surface, shaft, or locating feature, eliminating the need for additional bushings. Available in standard and custom shoulder lengths to meet exact application requirements.

Thread Configurations

Threaded section of reduced diameter available with Unified Coarse (UNC), Unified Fine (UNF), UNJF-3A (aerospace), and metric coarse/fine threads. Thread classes 2A, 3A, 6g. Precision rolled threads for superior fatigue life. Full thread or partial thread options.

Drive Types & Head Styles

Standard hex socket drive (Allen) for positive torque transmission. Also available with slotted drive, hex head, or custom drive configurations. Head styles include standard shoulder bolt head (reduced diameter) and heavy head options for increased bearing area.

Aerospace & Military Standards

Our MP159 shoulder bolts meet applicable sections of NASM 5160 (shoulder screws), NAS1802, and MS16995 for geometry. Full compliance with AMS 5841 (solution treated), AMS 5842 (work strengthened), and AMS 5843 (full condition) for material and heat treatment. Silver plating per AMS 2410 available for anti-galling.

Oil & Gas / NACE Grades

MP159 shoulder bolts for sour service manufactured to NACE MR0175/ISO 15156-3 and NACE MR0103 specifications. MP159's high chromium and molybdenum content provides exceptional resistance to sulfide stress cracking (SSC) in H₂S environments. Supplied with EN 10204 3.1/3.2 certifications and full NDT (PMI, UT, MPI) upon request.

Custom & Non-Standard Shoulder Bolts

Need a special shoulder diameter, non-standard shoulder length, proprietary drive, or unique head configuration? RAYCHIN engineers design and produce custom MP159 shoulder bolts to your exact specifications – any condition (annealed, cold worked, aged), with full material traceability. Prototype to production volumes supported.

Critical Applications of MP159 Shoulder Bolts

Aerospace & Defense

MP159 shoulder bolts used in aircraft landing gear assemblies, engine mounts, flight control linkages, and structural airframe joints. Precision shoulder provides exact location of components and acts as a pivot pin. Withstand extreme vibration, thermal cycling from -300°F to 1100°F, and high shear loads. Non-magnetic properties essential for sensitive instrumentation. MP159 is the preferred material for high-temperature aerospace fasteners.

Oil & Gas / Downhole Tools

MP159 shoulder bolts qualified per NACE MR0175 for downhole drilling tools, MWD/LWD equipment, wellhead connectors, and subsea actuators. Resist sulfide stress cracking (SSC) and pitting in H₂S/CO₂ environments at elevated pressures. Precision shoulder provides accurate location of components in confined spaces.

Medical & Surgical Implants

MP159 shoulder bolts used in surgical instruments, orthopedic external fixators, dental implants, and prosthetic devices. Full biocompatibility, excellent fatigue resistance for long-term cyclic loading, and non-magnetic for MRI compatibility. Precision shoulder provides exact location of articulating components.

Marine & Subsea

MP159 shoulder bolts in seawater pump linkages, subsea connector assemblies, ROV systems, and offshore platform components resist pitting and crevice corrosion in saltwater. Precision shoulder acts as bearing surface for rotating components. Virtually immune to crevice corrosion and pitting even at highest strength levels.

Power Generation

MP159 shoulder bolts in gas turbines, steam turbines, and nuclear reactor internals provide reliable fastening and location of sensor mounts and control linkages. Maintain clamping force and precise location after thousands of thermal cycles from cryogenic to 1100°F without relaxation.

Tooling & Die Applications

MP159 shoulder bolts (stripper bolts) used in stamping dies, injection molds, and progressive tooling to guide and limit stripper plates. Precision ground shoulder provides exact stripping distance with minimal wear. High strength and corrosion resistance extend tool life in harsh environments.

International Standards & Global Designations – MP159 Shoulder Bolts

RAYCHIN LIMITED manufactures MP159 shoulder bolts 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.

Designation	Standard / Specification	Description
UNS R30159	Unified Numbering System	Standard designation for MP159 alloy chemistry
AMS 5841	Aerospace Material Specification	Bar, rod, wire; solution heat treated (1900-1925°F, 4-8h, water quench)
AMS 5842	Aerospace Material Specification	Solution heat treated and work strengthened (cold worked)
AMS 5843	Aerospace Material Specification	Solution heat treated, work strengthened, and aged – full condition for maximum strength
ASTM F (pending)	Standard Specification	Wrought cobalt-nickel alloy for surgical implants
ASM Co-68	ASM Alloy Digest	Reference data for MP159 alloy properties
GE S-400	GE Aviation Specification	Engine fasteners material approval
PWA LCS	Pratt & Whitney Specification	Material approval for aerospace applications
ASME B18.3	American Society of Mechanical Engineers	Socket head cap screws – applicable sections for shoulder screws
NASM 5160	National Aerospace Standards	Shoulder screws, inch series
ISO 7378	International Organization for Standardization	Shoulder screws – metric series

UNS R30159 AMS 5841 AMS 5842 AMS 5843 ASM Co-68 GE S-400 PWA LCS ASME B18.3 NASM 5160 ISO 7378

Chemical Composition (Weight %) – MP159 Alloy for Shoulder Bolts

Our MP159 shoulder bolts are produced from vacuum induction melted (VIM) and vacuum arc remelted (VAR) material conforming to the following limits per AMS and industry standards.

Element	Min %	Max %	Typical
Cobalt (Co)	Balance	Balance	~35.7
Nickel (Ni)	25.0	26.0	25.5
Chromium (Cr)	18.0	20.0	19.0
Iron (Fe)	8.0	10.0	9.0
Molybdenum (Mo)	6.0	8.0	7.0
Titanium (Ti)	2.5	3.5	3.0
Niobium (Nb)	0.4	0.8	0.6
Aluminum (Al)	0.1	0.3	0.2
Carbon (C)	—	0.03	<0.03
Manganese (Mn)	—	0.20	<0.10
Silicon (Si)	—	0.20	<0.10
Sulfur (S)	—	0.010	<0.005
Phosphorus (P)	—	0.015	<0.008

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 shoulder bolts with precision-ground shoulders and rolled threads. It remains essentially non-magnetic (permeability ~1.00265 μ) 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).

Complete Mechanical & Physical Properties – MP159 Shoulder Bolts (MPa / ksi)

MP159 shoulder bolts 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 Shoulder Bolts

Condition / Specification	Tensile Strength (MPa)	Tensile Strength (ksi)	Yield Strength 0.2% (MPa)	Yield Strength 0.2% (ksi)	Elongation (%)	Hardness
Annealed / Solution Treated (AMS 5841)	848	123	400	58	60	20 HRC max
Solution Treated + Work Strengthened (48% cold work, AMS 5842)	1585	230	1413	205	12	38 HRC min
Cold Worked + Aged (AMS 5843) – Full Condition	1895 (min 1790)	275 (min 260)	1827 (min 1725)	265 (min 250)	8 (min 6)	44 HRC min
Aged Condition (typical maximum)	1930+	280+	1860+	270+	8	45-50 HRC

Physical Properties – MP159 Alloy

Property	Metric	Imperial	Notes
Density	8.33 g/cm³	0.301 lb/in³
Melting Range	1315-1427°C	2400-2600°F
Elastic Modulus (E) at 20°C	210-220 GPa	30.5-32.0 x 10³ ksi
Elastic Modulus at 232°C (450°F)	208 GPa	30.2 x 10³ ksi
Shear Modulus (G) at 20°C	75.8 GPa	11.0 x 10³ ksi
Poisson's Ratio	0.31	0.31
Thermal Expansion (25-100°C)	14.3 µm/m°C	7.94 µin/in°F
Thermal Conductivity	10.5 W/m·K	73 Btu·in/(hr·ft²·°F)
Electrical Resistivity	100 µΩ·cm	39.4 µΩ·in
Magnetic Permeability	~1.00265	~1.00265	Essentially non-magnetic

High‑Temperature Performance of MP159 Shoulder Bolts

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.

Elevated Temperature Capabilities

Property	Value	Notes
Maximum Service Temperature (continuous)	593°C (1100°F)	In fully work hardened and aged condition
Operating Temperature Range	-184°C to 593°C (-300°F to 1100°F)	Full operating temperature range
650°C Strength	Tensile ≥1000 MPa	Superior to many competing alloys
Cryogenic Performance	Excellent	No embrittlement down to -184°C (-300°F)
Oxidation Resistance	Good up to 1100°F	Resistant to high-temperature oxidation

High-Temperature Comparison – MP159 vs. MP35N

Alloy	Maximum Service Temperature	Typical Application
MP159	1100°F (593°C)	Turbine engine fasteners, high-temperature bolts
MP35N	800°F (427°C)	General purpose high-strength fasteners
Inconel 718	1300°F (704°C)	Higher temperature capability, lower strength than MP159 at moderate temps

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 Shoulder Bolts

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: 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.
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 Shoulder Bolts

All MP159 shoulder bolts are manufactured and tested to meet the following standards:

AMS 5841AMS 5842AMS 5843ASTM FNACE MR0175NACE MR0103API 20FASME B18.3NASM 5160ISO 7378GE S-400PWA LCSMS16995EN 10204 3.1/3.2

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 Shoulder Bolt Authority

Metallurgical expertise: Decades of experience with cobalt‑nickel superalloys. We ensure precise heat treatment: solution anneal (1900-1925°F), controlled cold work (48% reduction), and aging (1200-1250°F) per AMS 5843 schedules. In‑house PMI verifies chemistry of every heat. Our MP159 shoulder bolts achieve 260-280 ksi ultimate tensile strength with full traceability.

Global certifications: ISO 9001, AS9100D, ISO 13485 (medical), PED, API Q1, NADCAP accredited processes. All shoulder bolts supplied with EN 10204 3.1/3.2 certifications, NACE compliance when required.

Precision grinding & thread rolling: CNC centerless grinding ensures precise shoulder diameter tolerances (h6/h7). Precision thread rolling ensures accurate thread geometry per ASME/ISO standards. Class 2A/3A/6g thread fit. 100% inspection available.

Custom solutions: Special shoulder diameters, non-standard shoulder lengths, proprietary drives, tailored packaging. In-house metallurgical laboratory and failure analysis capabilities.

Contact the MP159 shoulder bolt experts

Request a quotation for MP159 shoulder bolts, precision shoulder screws, stripper bolts – any standard (ASME, ISO, 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 566

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