RAYCHIN LIMITED

Nitronic Shoulder Bolts – Comprehensive Product Range

Critical Applications of Nitronic Shoulder Bolts

International Standards & Global Designations – Nitronic Alloys

RAYCHIN LIMITED manufactures Nitronic shoulder bolts 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 shoulder bolts 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)

Nitronic 50 (UNS S20910)

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 (UNS S21800) contains high manganese and silicon 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 stainless steel while maintaining excellent ductility. Nitronic 50 (UNS S20910) combines high nitrogen content with molybdenum and niobium additions to achieve corrosion resistance superior to 316 stainless steel, with pitting resistance equivalent to super duplex grades. Both alloys retain their austenitic structure and remain non-magnetic even after severe cold working, making them ideal for applications requiring non-magnetic properties combined with high strength.

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

Nitronic shoulder bolts 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

Exceptional Galling Resistance of Nitronic Shoulder Bolts

Nitronic 60 is widely recognized as one of the most galling-resistant materials available, making it the preferred choice for shoulder bolts 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.

Galling Resistance Comparison

Threshold galling stress data from ASTM G98 testing. Higher values indicate better galling resistance.

Corrosion Resistance Properties

PREN calculated as %Cr + 3.3%Mo + 16%N. Nitronic 50's PREN of 32-36 exceeds that of 316 (24-26) and approaches super duplex grades.

• 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 shoulder bolts ideal for applications requiring frequent disassembly, sliding contact, or where lubricants cannot be used.
• Corrosion Resistance: Nitronic 50 provides corrosion resistance superior to 316 stainless steel in most environments, with particular excellence in chloride-containing media. The alloy's high PREN (32-36) ensures excellent pitting resistance equivalent to super duplex grades.
• High Strength: Both alloys offer approximately twice the yield strength of conventional 300-series stainless steels in the strain-hardened condition, allowing for reduced cross-sections or higher load capacities.
• 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.
• Cryogenic Toughness: Nitronic alloys retain excellent impact toughness at cryogenic temperatures, with Nitronic 50 qualified for service down to -269°C (-452°F).
• High-Temperature Properties: Nitronic 60 maintains useful strength up to 650°C (1200°F) with good oxidation resistance. Nitronic 50 offers excellent strength and corrosion resistance up to 650°C, making it suitable for high-temperature fasteners in chemical processing.
• 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 Shoulder Bolts

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

We offer surface finishes: plain (as-machined), passivated, or electropolished for medical and semiconductor applications. Controlled strain-hardening processes per ASTM A193 and AMS specifications ensure consistent mechanical properties. Shoulder bolts are manufactured with precision-ground shoulders to tight diametrical tolerances (typically h8/h9, with custom tolerances available). Specialized CNC turning, thread rolling, and centerless grinding ensure accurate geometry per ASME, ISO, and NAS standards. Class 2A/3A/6g thread fit. 100% inspection available including dimensional inspection, hardness 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.