RAYCHIN LIMITED

Nitronic Bolts – Complete Product Range

Critical Applications of Nitronic Bolts

International Standards & Global Designations – Nitronic Bolt Materials

RAYCHIN LIMITED manufactures Nitronic bolts from material conforming to the most widely used national and international specifications. All material is traceable to the mill.

Chemical Composition (Weight %) – Nitronic Alloys for Bolts

Our Nitronic bolts are produced from material conforming to the limits of applicable ASTM, AMS, and ASME standards.

Nitronic 50 (UNS S20910 / XM-19)

Nitronic 60 (UNS S21800 / Alloy 218)

Note: High silicon (3.5-4.5%) provides exceptional galling resistance and oxidation resistance.

Nitronic 32 (UNS S24100 / XM-28)

Note: High manganese content (11-14%) provides nitrogen strengthening with low nickel.

Nitronic 40 (UNS S21904 / 21-6-9)

Note: Known as 21-6-9 alloy, with excellent strength and corrosion resistance for aerospace applications.

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

Nitronic bolts are supplied in appropriate conditions (annealed, strain hardened) per ASTM A193, ASTM F593, and ASME specifications. Data represent typical values based on industry standards.

Nitronic 50 (XM-19) – Mechanical Properties

Nitronic 60 (Alloy 218) – Mechanical Properties

Nitronic 32 (XM-28) – Mechanical Properties

Nitronic 40 (21-6-9 / XM-11) – Mechanical Properties

High‑Temperature Mechanical Properties – Nitronic 50 (representative)

Low-Temperature Properties – Nitronic 50

Physical Properties – Nitronic Alloys

High‑Temperature Performance of Nitronic Bolts

Nitronic alloys maintain useful mechanical properties at elevated temperatures, making them suitable for many high‑temperature bolt applications. Nitronic 50 exhibits good strength up to 600°C (1112°F) with oxidation resistance similar to 304/316 stainless steels. It retains significant yield strength at 650°C (570 MPa tensile, 290 MPa yield). Nitronic 60 retains strength up to 570°F (300°C) and offers superior galling resistance even at elevated temperatures, with good oxidation resistance up to 815°C due to its high silicon content. Nitronic 32 (high manganese grade) provides strength up to 1100°F (593°C) with good oxidation resistance and is often used for furnace components and heat treating fixtures. Nitronic 40 offers good elevated temperature properties and oxidation resistance in air. For continuous service above 500°C, Nitronic 50 is preferred due to its molybdenum content. The alloys resist scaling in air up to 870°C (1600°F) intermittently. Nitronic 60's high silicon content improves oxidation resistance at high temperatures, making it suitable for exhaust system fasteners and heat treat fixtures.

Elevated Temperature Capabilities

Exceptional Corrosion Resistance of Nitronic Bolts

Nitronic alloys offer outstanding corrosion resistance in various environments, often surpassing conventional stainless steels. Nitronic 50 was developed to provide superior resistance to chloride pitting and crevice corrosion compared to 316L and 317L, with PRE (Pitting Resistance Equivalent) of 34‑38. It is highly resistant to stress corrosion cracking in chloride environments. Nitronic 60 provides excellent resistance to aqueous corrosion, similar to 304, but with superior resistance to galling and metal‑to‑metal wear. Nitronic 32 offers good general corrosion resistance, comparable to 304, with high strength. Nitronic 40 offers corrosion resistance similar to 304 but with higher strength and resists stress corrosion cracking in severe marine environments at ambient temperature.

• Pitting & Crevice Corrosion: Nitronic 50 outperforms 316L and 317L in ASTM G48 pitting tests. Critical pitting temperature (CPT) for Nitronic 50 is typically >40°C in 6% FeCl3, compared to 25°C for 316L. Nitronic 60 offers pitting resistance superior to 316 in chloride media.
• Stress Corrosion Cracking (SCC): Nitronic 50 exhibits excellent resistance to SCC in chloride environments. Nitronic 40 resists stress corrosion cracking in severe marine environments at ambient temperature. Nitronic 60 and 32 offer moderate resistance similar to 304.
• Galling Resistance: Nitronic 60 is world‑renowned for its galling resistance. In self‑mated tests, it exhibits threshold galling stress > 34 MPa (5 ksi) – orders of magnitude higher than 304 or 316. Ideal for threaded bolts subject to sliding contact, frequent assembly/disassembly, and vibration.
• Marine / Seawater: Nitronic 50 is widely used in seawater applications due to its high pitting resistance and low magnetic permeability. It remains non‑magnetic even after severe cold working, essential for marine instrumentation and underwater fasteners.
• NACE Compliance: Nitronic 50 and Nitronic 60 meet NACE MR0175 / ISO 15156-3 for sour service environments (up to hardness HRC 35 for Nitronic 50), making them suitable for oil & gas bolting.
• Sulfidation Resistance: Nitronic alloys perform well in sulfur‑containing environments, with Nitronic 60's high silicon content providing additional resistance.
• Intergranular Corrosion: All Nitronic grades resist sensitization due to low carbon content and nitrogen stabilization, passing ASTM A262 Practice E tests.
• Abrasion & Erosion Resistance: Nitronic alloys exhibit higher resistance to abrasion, erosion, and cavitation erosion than 304, 316, and 317L austenitic stainless steels due to their high work hardening rate.

Manufacturing Standards – Nitronic Bolts

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

We offer surface finishes: plain (as‑machined), passivated, electro‑polished. Silver plating per AMS 2410 available for anti‑seize and enhanced conductivity – recommended for aerospace bolts in high‑temperature applications. Controlled strain hardening and heat treatment processes per ASTM A193 ensure optimal mechanical properties. For Nitronic 50, solution annealing at 1065-1120°C (1950-2050°F) followed by water quenching. Nitronic 60 bolts are strain hardened to achieve required strength levels. NADCAP accredited processing available. Specialized heading, thread rolling, and precision machining for accurate bolt geometry per ASME, ISO, DIN, and NAS standards. Class 2A/3A/6g thread fit. 100% inspection available. Full traceability and destructive/non‑destructive testing available (UT, FPI, MPI). AS9100 and ISO 9001:2015 certified quality management. Build‑to‑print specials to customer specifications are available, including custom head styles, drives, and thread forms.