RAYCHIN LIMITED

Hex Bolts – Partial & Full Thread (DIN 931 / DIN 933 / ISO 4014 / ISO 4017)

Incoloy hex bolts manufactured to DIN 931 (partial thread), DIN 933 (full thread), ISO 4014, ISO 4017, and ASME B18.2.1 standards. Features a hex head for external wrenching, providing high torque capability and positive drive. Available in partial thread configuration for shear strength and alignment, or full thread configuration for maximum thread engagement. Ideal for high-temperature applications up to 1150°C for grade 800 series, and up to 540°C for acid service with grade 825. Available in sizes from M6 to M100 (metric) and 1/4" to 4" (inch) in various lengths. Precision rolled threads for superior strength and corrosion resistance.

Heavy Hex Bolts (DIN 6914 / ASME B18.2.1)

Incoloy heavy hex bolts manufactured to DIN 6914, ASME B18.2.1 (heavy hex series), and ASTM A325/A490 dimensional standards. Features a larger head configuration providing increased bearing area for high-pressure flange connections and pressure vessel applications. Essential for API 6A and ASME B16.5 bolting assemblies in high-temperature and corrosive environments. The heavier head distributes load more effectively and resists dilation at elevated temperatures. Available in all Incoloy grades. Sizes from 1/2" to 4" (M12 to M100). Supplied with matching Incoloy heavy hex nuts.

Flange Bolts (DIN 6921 / ISO 4162 / ASME B18.2.3.3M)

Incoloy flange bolts manufactured to DIN 6921, ISO 4162, and ASME B18.2.3.3M standards. Features an integrated flange under the head that provides a larger bearing surface, eliminating the need for separate washers. The flange distributes clamping load evenly and provides vibration resistance. Ideal for high-temperature applications up to 1150°C for grade 800 series, and for acid service with grade 825. Available with serrated flange for anti-rotation. Precision rolled threads for superior fatigue life. Sizes from M6 to M36 (metric) and 1/4" to 1-1/2" (inch).

Incoloy Bolts – API & NACE Compliant

Incoloy bolts certified to NACE MR0175 / ISO 15156 for sour service applications in oil and gas industry. Incoloy 825 and 925 grades are qualified for H₂S environments at elevated temperatures. Incoloy 925 offers premium resistance to sulfide stress cracking with yield strengths up to 760 MPa in aged condition. Suitable for wellhead equipment, valve assemblies, subsea connections, and refinery applications. Available in all configurations with 100% NDT available including PMI, UT, and MPI. Full traceability and material certifications per ASTM standards. API 6A closure bolts available with full traceability.

Custom & Specialty Incoloy Bolts

Need a special head style, unusual thread configuration, or custom length for your extreme environment application? RAYCHIN engineers work with you to produce custom Incoloy bolts to your drawing. Options include T-head bolts, eye bolts, U-bolts, anchor bolts, socket head cap screws, and bolts with drilled heads for safety wiring. Expert heat treatment (solution annealed for 800/825, aged for 925) ensures optimum properties. 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-iron-chromium superalloys. We ensure proper heat treatment for each grade—solution annealing for 800/825, optimized annealing for 800H/HT, and precise aging for 925—to achieve optimal properties. Every heat is verified by in-house PMI testing to confirm chemistry. Our bolts provide the exact balance of high-temperature strength and corrosion resistance required for your application.

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 Incoloy bolts meet applicable ASTM, ASME, NACE MR0175, and API standards.

Precision head forming & thread rolling

In-house cold heading, hot forging, and precision thread rolling capabilities ensure consistent head dimensions and thread geometry. Precision rolled threads provide superior fatigue life and dimensional accuracy. 100% thread and dimensional inspection available. Controlled underhead fillet for improved fatigue resistance in high-temperature cyclic applications.

Custom solutions

Need a special head style, unusual thread configuration, or custom material certification for your extreme environment application? Our engineering team works with you to produce custom Incoloy bolts to your drawing. We provide specialized surface treatments, passivation, and NACE MR0175 compliant processing per customer requirements.