MP159 Fasteners – The Complete Guide to Ultra-High-Strength Cobalt Alloy Bolts, Nuts & Studs
When applications demand the highest levels of strength, corrosion resistance, and fatigue life, MP159 fasteners are the premier choice for engineers worldwide. RAYCHIN LIMITED, a specialized manufacturer and global supplier of high-performance alloy fasteners, brings decades of expertise to the production of MP159 bolts, nuts, washers, stud bolts, and custom-machined parts. This guide combines product details with in-depth technical knowledge to help you make informed decisions.
Product Range
MP159 Bolts
Hex bolts, heavy hex bolts, socket head cap screws, and shoulder bolts. Sizes M2–M36, #0–1-1/2″.
MP159 Nuts
Hex nuts, heavy hex nuts, lock nuts, and custom nuts. Metric and imperial sizes available.
MP159 Washers
Plain washers, spring washers, and custom OD/ID thickness. Engineered for high-load applications.
MP159 Stud Bolts
Full threaded and double end studs. ASME B16.5 / B18.2.1 compliant.
MP159 Screws
Machine screws, set screws, and captive screws. Drive types: slotted, Phillips, hex socket.
Custom MP159 Parts
Special threads, non-standard heads, and precision-machined components per customer drawings.
Material Specifications & Standards
Available Sizes & Thread Standards
Larger or special sizes can be manufactured on request. Please contact our sales team for a custom quotation.
What is MP159 Alloy? (Technical Guide)
MP159 is a cobalt-nickel-chromium-molybdenum alloy with the UNS designation R30159. It is a precipitation-hardenable, high-strength alloy that offers a unique combination of ultra-high tensile strength, excellent corrosion resistance, and exceptional fatigue life. MP159 achieves its remarkable properties through a combination of cold working and subsequent aging, which produces a fine dispersion of strengthening precipitates.
The typical chemical composition of MP159 includes:
- Cobalt (Co): 35–38%
- Nickel (Ni): 25–27%
- Chromium (Cr): 19–21%
- Molybdenum (Mo): 6–8%
- Iron (Fe): 9–11%
- Titanium (Ti): 2.5–3.5%
- Carbon (C): ≤0.04%
This composition, combined with controlled processing, gives MP159 its outstanding mechanical performance in demanding environments.
Key Properties of MP159 Fasteners
- Ultra-High Tensile Strength: MP159 can achieve tensile strengths up to 1795 MPa (260 ksi) after cold working and aging, making it one of the strongest cobalt-based alloys for fasteners.
- Exceptional Corrosion Resistance: The alloy resists pitting, crevice corrosion, and stress-corrosion cracking in chloride environments, seawater, and many acids.
- Superior Fatigue Strength: MP159 exhibits excellent fatigue resistance even at high stress levels, crucial for rotating and vibrating components.
- Wide Temperature Range: The alloy maintains mechanical properties from cryogenic temperatures up to approximately 500°C (932°F) continuous, with short-term exposure up to 600°C (1112°F).
Applications of MP159 Fasteners
- Aerospace & Defense: Engine mounts, airframe fasteners, landing gear, and high-temperature structural components.
- Oil & Gas: Downhole tools, wellhead components, and sour service equipment requiring high strength and H₂S resistance.
- Marine & Offshore: Shaft couplings, propeller fasteners, and subsea connectors exposed to seawater.
- High-Performance Motorsport: Lightweight, high-strength fasteners for engine and chassis applications.
- Chemical Processing: Equipment exposed to aggressive acids and chloride-bearing environments.
Quality Assurance & Testing
RAYCHIN LIMITED is committed to supplying MP159 fasteners that meet the highest quality standards. Our rigorous quality control includes:
- Material Test Certificates (EN 10204 3.1 / 3.2)
- Full chemical analysis and mechanical testing (tensile, yield, elongation)
- Positive Material Identification (PMI) for alloy verification
- Hardness testing (Rockwell C, Brinell, Vickers)
- Corrosion resistance testing (salt spray, pitting, intergranular)
- Dimensional inspection with calibrated gauges
- Third-party inspection and testing available upon request
How to Select the Right MP159 Fastener
- Mechanical Requirements: Determine required tensile strength, yield strength, and fatigue life. MP159 can be processed to different strength levels via cold work and aging.
- Corrosive Environment: Identify chemicals, temperature, and chloride concentration. MP159 excels in chloride-rich and sour environments.
- Standards and Certification: Specify AMS 5842/5843 or customer-specific standards, and any additional requirements like NACE MR0175.
- Size and Thread: Confirm diameter, pitch, length, and thread standard. Custom threads available.
- Quantity and Lead Time: Stock items dispatch within 3-5 days; custom orders typically require 3-6 weeks.
Frequently Asked Questions
What is MP159 alloy?
MP159 is a cobalt-nickel-chromium-molybdenum alloy (UNS R30159) with ultra-high strength, excellent corrosion resistance, and outstanding fatigue life, achieved through cold working and aging.
Which standards cover MP159 fasteners?
MP159 fasteners are typically manufactured to AMS 5842 (bar) and AMS 5843 (wire). Other customer-specific standards can also be accommodated.
What are the key applications of MP159 fasteners?
MP159 fasteners are used in aerospace engines, airframes, oil & gas downhole tools, marine shafts, and high-performance motorsport components where high strength and corrosion resistance are critical.
What is the maximum service temperature for MP159 fasteners?
MP159 retains its mechanical properties from cryogenic temperatures up to approximately 600°C (1112°F) for short-term exposure, and around 500°C (932°F) for continuous service.
Does RAYCHIN provide material certificates for MP159 fasteners?
Yes, RAYCHIN LIMITED provides EN 10204 3.1 / 3.2 certificates, chemical analysis, tensile reports, PMI, hardness testing, and additional corrosion testing as required.
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