1. What are MP159 Fasteners?

MP159 fasteners are high-strength threaded components—such as bolts, screws, nuts, and studs—manufactured from MP159 alloy.

It is crucial to understand that MP159 is first and foremost a proprietary cobalt-nickel-chromium superalloy (originally developed by a company now part of ATI Metals), and the fasteners are a primary application of this material. The alloy is processed through a unique "Multiphase" heat treatment, which gives it an exceptional combination of properties unmatched by common high-strength steels or even other superalloys like A-286 or Inconel 718.

2. Key Characteristics & Properties

MP159 fasteners are renowned for the following characteristics, which are direct results of the alloy's composition and processing:

• Ultra-High Strength: They offer an ultimate tensile strength typically in the range of 260 to 300 ksi (1,790 to 2,070 MPa), maintaining this strength up to about 800°F (427°C). This is significantly stronger than Grade 5, Grade 8, or even 300M steel.

• Excellent Stress Rupture and Creep Resistance: They can withstand high loads under tension for extended periods at elevated temperatures without failing or deforming over time.

• Outstanding Fatigue Strength: The alloy's microstructure provides exceptional resistance to failure under cyclic loading, making it ideal for applications with vibration and repeated stress cycles.

• Good Corrosion Resistance: MP159 offers excellent resistance to stress corrosion cracking (SCC) and performs well in saltwater and other corrosive environments, far surpassing high-strength steels.

• Controlled Thermal Expansion: Its coefficient of thermal expansion is relatively low and predictable, which is critical in assemblies with dissimilar materials subjected to wide temperature ranges.

• Non-Magnetic: The alloy is inherently non-magnetic, a critical requirement for applications involving sensitive electronics or magnetic fields.

3. Main Application Fields

Due to their premium properties and cost, MP159 fasteners are used in the most demanding, mission-critical applications where failure is not an option.

• Aerospace & Defense:

  • Jet Engines: Used extensively in compressor sections, fan disks, and other critical assemblies where high strength-to-weight ratio and temperature resistance are paramount.

  • Airframes: In highly stressed locations on military and commercial aircraft.

  • Missiles & Rockets: For structural connections that must withstand extreme forces and temperatures.

• Oil & Gas (Downhole Tools):

  • Used in deep well drilling equipment, such as Measurement-While-Drilling (MWD) and Logging-While-Drilling (LWD) tools. They withstand high downhole pressures, corrosive sour gas (H₂S), and high temperatures (HPHT wells).

• High-Performance Automotive & Racing:

  • Used in critical components of engines, transmissions, and turbocharger systems in Formula 1, Top Fuel dragsters, and other racing applications where extreme strength and reliability are needed.

• Specialized Industrial Equipment:

  • Applications involving high cyclic loads, severe vibrations, and corrosive conditions where standard fasteners would fail.

MP159 Fasteners are high-performance components made from a cobalt-nickel-based superalloy, valued for their ultra-high strength (up to 300 ksi), excellent fatigue life, and good corrosion resistance. They retain these properties at temperatures up to ~800°F. Their primary use is in critical aerospace applications (jet engines, airframes), demanding oil & gas downhole tools, and high-performance racing systems, where failure of a single component is catastrophic.