Hastelloy C276 Fasteners: Bolts, Nuts, Screws, Studs & Washers for the World's Most Aggressive Corrosive Environments

When chemical processing equipment, pollution control systems, and pharmaceutical reactors face hot sulfuric acid, wet chlorine gas, or mixed oxidizing-reducing media, standard stainless steels fail within weeks. Hastelloy C276 fasteners—with their unique nickel-molybdenum-chromium-tungsten composition—deliver what virtually no other alloy can: near-universal corrosion resistance across both oxidizing and reducing environments. RAYCHIN LIMITED, a specialist global manufacturer and supplier of Hastelloy fasteners with decades of in-house experience, produces the complete range of C276 bolts, nuts, screws, studs, and washers for the world's most demanding industries.

1. What Is Hastelloy C276? Composition and Why It Works

Hastelloy C276 (UNS N10276) is a nickel-molybdenum-chromium alloy with a small but critical tungsten addition. The chemistry is deliberately balanced to resist the two primary corrosion mechanisms that destroy lesser alloys:

• Reducing environments (hydrochloric acid, sulfuric acid, phosphoric acid): resisted by the high molybdenum (15–17%) and tungsten (3–4.5%) content.
• Oxidizing environments (nitric acid, wet chlorine, ferric chloride): resisted by the chromium (14.5–16.5%) content.
• Chloride-induced localized attack (pitting, crevice corrosion): resisted by the combined Mo + W synergy, delivering a PREN of approximately 69—nearly triple that of 316L.

The table below summarizes the nominal Hastelloy C276 chemical composition per ASTM B574.

2. Complete Product Range: Bolts, Nuts, Screws, Studs, and Washers

RAYCHIN manufactures the full spectrum of Hastelloy C276 fasteners in both metric and imperial sizes. Whether you need a single custom stud or a full project package for an FGD absorber, we deliver certified product on time.

Hastelloy C276 Fastener Dimensions — Size Range Overview

3. Mechanical Properties and Temperature Capability

Hastelloy C276 is a solid-solution strengthened alloy—it cannot be hardened by heat treatment, but it provides excellent ductility and reliable strength across a wide temperature range. Typical room-temperature properties in the solution-annealed condition per ASTM B574 are:

Maximum service temperature: For continuous service under load, C276 is limited to approximately 600°C (1112°F). In non-load-bearing oxidizing atmospheres, it resists scaling to about 1100°C. For applications requiring both high temperature and high strength, Nimonic or Waspaloy fasteners should be considered.

4. Corrosion Resistance: The Defining Advantage

The reason engineers specify Hastelloy C276 fasteners is simple: it survives environments that destroy everything else. Key performance characteristics include:

• Wet chlorine and hypochlorite: Outstanding resistance—one of the few alloys suitable for chlorine drying towers and bleach plant equipment.
• Sulfuric acid: Resists both dilute and concentrated acid across a wide temperature range, including contaminated streams containing oxidizing species.
• Hydrochloric acid: Excellent resistance at all concentrations and temperatures, particularly when oxidizing contaminants are present.
• Mixed acids: The simultaneous Cr + Mo + W synergy handles oxidizing-reducing mixtures that defeat single-mechanism alloys.
• Chloride pitting and crevice corrosion: PREN ~69 provides an enormous safety margin in seawater and high-chloride brines.
• Chloride stress corrosion cracking: Effectively immune due to the high nickel content.

5. Standards, Grades, and Certification

RAYCHIN manufactures Hastelloy C276 fasteners to the following international standards:

• ASTM B574 – Nickel-molybdenum-chromium alloy bar, for the raw material.
• ASTM F468 – General requirements for nonferrous bolts, hex cap screws, and studs.
• NACE MR0175 / ISO 15156 – Suitable for sour service in the solution-annealed condition (hardness ≤ 100 HRB).
• EN 10204 Type 3.1 / 3.2 – Full material certification with third-party witness options.
• NORSOK M-650 – Qualification for Norwegian continental shelf projects upon request.

Every shipment is accompanied by Positive Material Identification (PMI) reports generated by optical emission spectrometry on the finished fasteners, ensuring that the delivered product is genuine UNS N10276—not a lower-grade substitute.

6. Industries and Applications Served

Hastelloy C276 fasteners are specified across a wide range of aggressive chemical and environmental applications. Key industries include:

• Flue Gas Desulfurization (FGD) – Absorber internals, spray headers, and mist eliminators exposed to acidic chloride slurries.
• Chemical Processing – Reactors, heat exchangers, and piping handling sulfuric, hydrochloric, and mixed acids.
• Pulp & Paper – Bleach plant washers, chlorine dioxide stages, and digester components.
• Pharmaceutical – API synthesis reactors exposed to oxidizing acids and solvent mixtures.
• Pollution Control – Wet scrubbers, incinerator quench systems, and wastewater treatment.
• Oil & Gas – Sour gas wellheads, refinery overhead systems, and subsea components.
• Nuclear Fuel Reprocessing – Nitric acid dissolution and separation equipment.
• Marine Engineering – Exhaust scrubber wash water systems and offshore desalination.

7. Why RAYCHIN LIMITED for Hastelloy C276 Fasteners?

• True manufacturer: We control CNC machining, solution annealing, thread rolling, and testing under one roof—no subcontracting, no quality gaps.
• Deep inventory: C276 bar in diameters from 1/4″ to 2-1/2″ for rapid fulfillment of standard and custom orders.
• Full certification: EN 10204 3.1 as standard; 3.2 with third-party witness on request. PMI and mechanical test reports included.
• Anti-galling expertise: Rolled threads, pre-applied anti-seize coatings, and dissimilar nut pairing recommendations.
• Global delivery: We ship to chemical plants, refineries, and OEMs worldwide with full export documentation.

8. Frequently Asked Questions