RAYCHIN LIMITED

Hex Nuts (DIN 934 / ISO 4032 / ASME B18.2.2)

Alloy 20 hex nuts manufactured to DIN 934, ISO 4032 (Style 1), ISO 4033 (Style 2), and ASME B18.2.2 standards. Available in UNC, UNF, and metric coarse/fine threads. Precision tapped to Class 2B and 3B tolerances for reliable engagement with mating bolts and studs. Ideal for high-temperature corrosive applications up to 538°C in pressure vessels, flange connections, and structural assemblies. Available in sizes from M3 to M100 (metric) and #4 to 4" (inch). Supplied in solution annealed condition per ASTM B473. Proof load testing ensures compatibility with mating fasteners.

Heavy Hex Nuts (DIN 6915 / ISO 4034 / ASME B18.2.2)

Alloy 20 heavy hex nuts manufactured to DIN 6915, ISO 4034, and ASME B18.2.2 standards. Features a larger wrenching surface compared to standard hex nuts, providing increased bearing area for high-temperature flange connections and pressure vessel applications. Essential for API 6A and ASME B16.5 bolting assemblies in corrosive environments. The heavier cross-section distributes load more effectively and resists dilation at elevated temperatures. Available with controlled hardness ≤ 35 HRC for NACE MR0175 sour service compliance. Sizes from 1/4" to 4" (M6 to M100).

Jam Nuts & Thin Nuts (DIN 439 / ISO 4035 / ASME B18.2.2)

Alloy 20 jam nuts manufactured to DIN 439, ISO 4035, and ASME B18.2.2 standards. Reduced height nuts designed for applications with limited clearance or as locking nuts in conjunction with standard hex nuts. Ideal for adjustment applications and where space constraints require thinner profiles. Available in UNC, UNF, and metric threads with Class 2B and 3B tolerances. Suitable for high-temperature service up to 538°C in valve assemblies, instrumentation, and control systems. Precision machined from solution annealed Alloy 20. Sizes from M3 to M100 and #4 to 4".

Lock Nuts & Self-Locking Nuts (DIN 980 / DIN 985 / ISO 7040 / ISO 10511)

Alloy 20 lock nuts including all-metal lock nuts (DIN 980, ISO 7042) and nylon insert lock nuts (DIN 985, ISO 7040, ISO 10511). All-metal lock nuts feature controlled thread deformation for prevailing torque up to 538°C. Nylon insert lock nuts provide consistent prevailing torque for repeated use up to 120°C. Designed for high-vibration environments where fastener retention is critical. Available in hex and heavy hex configurations. Suitable for gas turbine assemblies, aerospace components, and high-temperature corrosive applications. Sizes from M3 to M48.

Slotted Nuts & Castle Nuts (DIN 979 / ASME B18.2.2)

Alloy 20 slotted nuts and Alloy 20 castle nuts manufactured to DIN 979 and ASME B18.2.2 standards. Features slots cut across the flats to accept a cotter pin or safety wire for positive locking. Ideal for applications requiring absolute retention in corrosive environments, such as shaft ends, turbine components, and critical machinery. Available in hex and heavy hex configurations with various slot dimensions. Precision machined from solution annealed Alloy 20. Sizes from M6 to M100 and 1/4" to 4".

Custom & Specialty Nuts

Need a special thread configuration, unusual size, or custom locking feature for your corrosive application? RAYCHIN engineers work with you to produce custom Alloy 20 nuts to your drawing. Options include coupling nuts, weld nuts, tee nuts, wing nuts, cap nuts, and nuts with unusual locking elements. Expert heat treatment (solution annealed at 1030-1120°C) ensures optimum corrosion resistance. Manufactured to NAS, AN, MS, ANSI, ASTM, ASME, SAE, API, NACE, ISO, DIN, KS standards.

Metallurgical competence

Engineers on staff with deep expertise in nickel-based superalloys. We ensure proper solution annealing (1030-1120°C) for optimal corrosion resistance across all Alloy 20 nuts. Every heat is verified by in-house PMI testing to confirm chemistry. With 32-38% nickel and copper-molybdenum additions, our nuts provide exceptional resistance to sulfuric acid, phosphoric acid, and chloride stress corrosion cracking.

Global approvals & traceability

Our quality system is ISO 9001:2015 and AS9100D certified; we also comply with NAS, AN, MS, ANSI, ASTM, ASME, SAE, API, NACE, ISO, DIN and KS. Full material traceability from melt to final packaging (EN 10204 3.1/3.2). Third-party inspections (ABS, DNV, Lloyds) available. All Alloy 20 nuts meet applicable ASTM B473, ASME SB473, NACE MR0175, and all relevant nut standards.

Precision tapping & thread forming

In-house CNC tapping and thread forming capabilities ensure precise thread geometry and consistent mechanical properties. Available thread classes up to 3B and UNJ-3B. 100% thread inspection available. Proof load testing per ASTM A453 ensures nuts meet or exceed specified strength requirements.

Custom solutions

Need a special thread configuration, unusual size, or custom locking feature for your corrosive application? Our engineering team works with you to produce custom Alloy 20 nuts to your drawing. We provide specialized surface treatments, passivation, and NACE MR0175 compliant processing per customer requirements.