RAYCHIN LIMITED

Nimonic Fasteners – Comprehensive Product Range

Critical Applications of Nimonic Fasteners

International Standards & Global Designations – Nimonic Fasteners

RAYCHIN LIMITED manufactures Nimonic fasteners 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 %) – Nimonic Alloys

Our Nimonic fasteners are produced from vacuum induction melted (VIM) and vacuum arc remelted (VAR) material conforming to the limits of applicable AMS and BS standards.

Nimonic 90 (UNS N07090 / W.Nr 2.4632)

Nimonic 80A (UNS N07080 / W.Nr 2.4952)

Nimonic 75 (UNS N06075)

Metallurgical note: Nimonic alloys are precipitation-hardening nickel-based superalloys strengthened through the formation of gamma prime (γ') phase Ni₃(Al, Ti) in a disordered FCC matrix. Nimonic 90 contains cobalt additions for enhanced solid solution strengthening and creep resistance at elevated temperatures . Nimonic 80A is strengthened with aluminum and titanium additions and offers good creep and oxidation resistance up to 800°C . Nimonic 75 is a solid-solution strengthened alloy with good oxidation resistance and fabricability . The alloys are produced by vacuum induction melting (VIM) and vacuum arc remelting (VAR) to ensure high purity and consistent properties .

Complete Mechanical & Physical Properties – Nimonic Alloys (MPa / ksi)

Nimonic fasteners are supplied in fully heat-treated condition per applicable AMS and BS specifications. Data represent typical values based on industry standards.

Nimonic 90 – Mechanical Properties

Nimonic 80A – Mechanical Properties

Nimonic 75 – Mechanical Properties (Annealed)

Physical Properties – Nimonic Alloys

High‑Temperature Performance of Nimonic Fasteners

Nimonic alloys are renowned for exceptional high-temperature strength and stability, maintaining useful mechanical properties up to 950°C (1740°F) in oxidizing atmospheres . Nimonic 90 exhibits high stress-rupture strength and excellent creep resistance up to 920°C, making it ideal for critical rotating applications in gas turbines . The alloy maintains approximately 60% of its room temperature tensile strength at 815°C, with yield strength of 517 MPa (75 ksi). Nimonic 80A offers good creep and oxidation resistance up to 800°C and is widely used in automotive and industrial gas turbine applications . Nimonic 75 provides good oxidation resistance up to 1050°C for less demanding applications .

Elevated Temperature Capabilities

Exceptional Corrosion Resistance of Nimonic Fasteners

Nimonic alloys offer outstanding corrosion resistance in high-temperature oxidizing environments, making them suitable for the most demanding applications in gas turbines, aerospace, and industrial processing. The chromium content (18-21%) provides excellent oxidation resistance by forming a protective Cr₂O₃ layer at elevated temperatures. Cobalt additions in Nimonic 90 enhance hot corrosion resistance and stability during long-term operation .

• Oxidation Resistance: Outstanding resistance to scaling and oxidation up to 950°C under continuous exposure. Forms protective oxides (Cr₂O₃, Al₂O₃, TiO₂) that provide excellent high-temperature corrosion resistance.
• Hot Corrosion: Good resistance to hot corrosion in combustion environments. Nimonic 90 is designed to operate in hot gas zones where long-term thermal stability is required .
• Sulfidation Resistance: Nimonic alloys perform well in sulfur-containing environments, though extremely sulfur-rich environments at very high temperatures should be avoided .
• Salt Spray Environments: Performs well in salt spray environments found in marine gas turbine service.
• Solution Treated Condition: Solution treated material offers the best corrosion resistance.
• Bimetallic Corrosion: Can be safely connected to other nickel-based superalloys, stainless steels, and titanium alloys with appropriate precautions. Silver-plated threads (AMS 2410) reduce galvanic corrosion risk.

Manufacturing Standards – Nimonic Fasteners

All Nimonic fasteners are manufactured and tested to meet the following standards:

We offer surface finishes: plain (as-machined), chemical cleaned, passivated. Silver plating per AMS 2410 available for anti‑seize and enhanced conductivity – recommended for aerospace self-locking nuts. Controlled solution and precipitation heat treatment processes per BS HR2 and AMS specifications ensure optimal mechanical properties. Standard heat treatment for Nimonic 90 includes solution treatment at 1080°C (1975°F) for 8 hours followed by air cool or oil/water quench, and precipitation hardening at 700°C (1290°F) for 16 hours . NADCAP accredited heat treatment processes. Specialized heading, thread rolling, and precision machining for accurate fastener geometry per international standards. Full traceability and destructive/non‑destructive testing available (UT, FPI, MPI). AS9100 and ISO 9001:2015 certified quality management. ISO 13485 certified for medical applications with cleanroom packaging available. Build-to-print specials to customer specifications are available.