RAYCHIN LIMITED

Nitronic Lock Nuts – Comprehensive Product Range

Critical Applications of Nitronic Lock Nuts

International Standards & Global Designations – Nitronic Lock Nuts

RAYCHIN LIMITED manufactures Nitronic lock nuts from vacuum arc remelted (VAR) or electroslag remelted (ESR) material conforming to the most widely used national and international specifications. All material is traceable to the mill.

Chemical Composition (Weight %) – Nitronic Alloys

Our Nitronic lock nuts are produced from vacuum arc remelted (VAR) or electroslag remelted (ESR) material conforming to the limits of applicable AMS and ASTM standards.

Nitronic 60 (UNS S21800) – Chemical Composition

Nitronic 50 (UNS S20910 / XM-19) – Chemical Composition

Metallurgical note: Nitronic alloys are nitrogen-strengthened austenitic stainless steels that achieve high strength through nitrogen solid solution strengthening rather than precipitation hardening. Nitronic 60 contains high manganese (7-9%) and silicon (3.5-4.5%) additions that provide exceptional galling and wear resistance by promoting the formation of deformation-induced martensite and reducing friction coefficients. The alloy exhibits approximately twice the yield strength of 304 and 316 stainless steels while maintaining excellent ductility. Nitronic 50 combines high nitrogen content with molybdenum and niobium additions to achieve corrosion resistance superior to 316 stainless steel, with PREN of 34 (compared to 25 for 316L). Both alloys retain their austenitic structure and remain non-magnetic (permeability <1.02) even after severe cold working. Nitronic 50 is listed in NACE MR0175 for sour service applications, offering excellent resistance to sulfide stress cracking.

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

Nitronic lock nuts are supplied in strain-hardened condition (typically Condition B for fasteners) or annealed condition per applicable ASTM and AMS specifications. Data represent typical values based on industry standards.

Nitronic 60 – Mechanical Properties

Nitronic 50 – Mechanical Properties

Physical Properties – Nitronic Alloys

PREN calculated as %Cr + 3.3%Mo + 16%N. Nitronic 50's PREN of 34 exceeds 316L (25).

Exceptional Galling & Corrosion Resistance of Nitronic Lock Nuts

Nitronic 60 is widely recognized as one of the most galling-resistant materials available, making it the preferred choice for lock nuts subject to frequent disassembly, sliding contact, or high-vibration environments. The alloy's unique combination of high manganese and silicon content promotes the formation of deformation-induced martensite during sliding contact, which reduces friction coefficients and prevents adhesive wear. Galling resistance tests show that Nitronic 60 exhibits threshold galling stresses approximately four times higher than 316 stainless steel, allowing threaded fasteners to be repeatedly assembled and disassembled without seizing. Nitronic 50 offers enhanced corrosion resistance superior to 316 stainless steel with PREN of 34, making it suitable for sour service applications per NACE MR0175.

Galling Resistance & Performance Characteristics

Corrosion Resistance Properties

• Galling Resistance: Nitronic 60 offers exceptional resistance to galling and seizing, with threshold galling stresses approximately 4x higher than 316 stainless steel. This makes Nitronic 60 lock nuts ideal for applications requiring frequent disassembly, where threads would otherwise seize or tear.
• High Strength: Both alloys offer approximately twice the yield strength of conventional 300-series stainless steels in the annealed condition. Strain-hardened versions achieve even higher strengths, allowing for reduced cross-sections or higher load capacities.
• Corrosion Resistance: Nitronic 50 provides corrosion resistance superior to 316 stainless steel in most environments, with PREN of 34 ensuring excellent pitting resistance equivalent to super duplex grades. Nitronic 60 offers chloride pitting resistance superior to 316.
• Sour Service Qualification: Nitronic 50 is listed in NACE MR0175 / ISO 15156-3 for oil and gas applications requiring resistance to sulfide stress cracking.
• Non-Magnetic Properties: Both Nitronic alloys remain essentially non-magnetic even after severe cold working (permeability <1.02), making them suitable for medical, electronic, and instrumentation applications where magnetic interference must be avoided.
• High-Temperature Properties: Nitronic 60 maintains useful strength up to 650°C (1200°F) with oxidation resistance similar to Type 321. Nitronic 50 offers excellent strength up to 650°C, making it suitable for high-temperature fasteners in chemical processing.
• Cryogenic Toughness: Nitronic alloys retain excellent impact toughness at cryogenic temperatures, with Nitronic 50 qualified for service down to -269°C (-452°F).
• Wear Resistance: The high work-hardening rates of Nitronic alloys provide excellent wear resistance in sliding applications, with surface hardness increasing under service conditions.

Manufacturing Standards – Nitronic Lock Nuts

All Nitronic lock nuts are manufactured and tested to meet the following standards:

We offer surface finishes: plain (as-machined), passivated, electropolished, or silver-plated per AMS 2410 for enhanced anti-galling and conductivity. Controlled strain-hardening processes per ASTM A193 and AMS specifications ensure consistent mechanical properties. Lock nuts are manufactured with precision tapping and thread forming to achieve reliable self-locking torque values per applicable aerospace and military standards. Specialized CNC machining and thread rolling ensure accurate geometry with Class 2B/3B/6H thread fit. 100% inspection available including dimensional inspection, proof load testing, and non-destructive examination. Full traceability and material test reports (MTR) available. 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.