Incoloy Fasteners – The Complete Guide to Iron-Nickel-Chromium Alloy Bolts, Nuts & Studs
When your application demands a balance of high-temperature strength, oxidation resistance, and excellent corrosion protection at a more economical cost than pure nickel alloys, Incoloy fasteners are the proven solution. RAYCHIN LIMITED produces the complete range of Incoloy 800, 800H, 800HT, 825, and 925 hex bolts, stud bolts, socket head cap screws, threaded rod, heavy hex nuts, and washers[reference:5]. This guide consolidates our metallurgical expertise to help you specify the correct grade.
Product Range
Incoloy 800/800H Bolts
Hex bolts per ASME B18.2.1. Sizes 1/4″–2″ and M6–M48. Ideal for furnace flanges and high-temperature piping.
Incoloy 825 Stud Bolts
Double-end studs per ASME B16.5. Outstanding resistance to sulfuric and phosphoric acids.
Incoloy 925 Bolts
Precipitation-hardened, tensile ≥965 MPa (140 ksi). For high-strength sour service applications[reference:6].
Incoloy 800HT Socket Head Screws
Compact high-torque fastening for confined spaces. Sizes #4–1″ and M3–M24.
Incoloy Threaded Rod
Continuous-thread studding in 800, 800H, 825, 925. Diameters 1/4″–2-1/2″ and M6–M64.
Incoloy Heavy Hex Nuts
Proof-load matched to corresponding bolts. All-metal prevailing-torque lock nuts available.
Material Grades & Standards
Incoloy 825 vs 925: Strength vs Corrosion Resistance
Applications
- Chemical Processing: Reactor bolts, heat exchanger fasteners, and piping studs handling sulfuric and phosphoric acids.
- Petrochemical & Refining: Furnace flanges, high-temperature piping, and reformer fasteners.
- Oil & Gas: Incoloy 925 wellhead studs and sour service bolts requiring high strength and H₂S resistance.
- Power Generation: Boiler components, steam line fasteners, and heat recovery systems.
- Marine & Offshore: Incoloy 825 fasteners for seawater-exposed piping and equipment.
- Industrial Furnaces: 800H/800HT fasteners for retorts, muffles, and radiant tubes.
Quality Assurance
- EN 10204 3.1 / 3.2 Material Test Certificates
- Positive Material Identification (PMI) reports
- Mechanical testing: tensile, yield, elongation
- Hardness verification (HRC 38 max for 925)
- Third-party inspection available
Frequently Asked Questions
What is the difference between Incoloy 800, 825, and 925?
800/800H/800HT are iron-nickel-chromium alloys with excellent high-temperature oxidation resistance. 825 adds molybdenum and copper for superior acid resistance. 925 is precipitation-hardened, offering tensile strength ≥965 MPa while retaining corrosion resistance[reference:7].
Which standards cover Incoloy fasteners?
ASTM B408 (800/800H/800HT), ASTM B425 (825), and ASTM B805 (925/945)[reference:8].
What is the maximum service temperature?
800H/800HT: up to 1100°C in oxidizing atmospheres. 825: ~540°C. 925: ~650°C.
Does RAYCHIN provide material certificates?
Yes, EN 10204 3.1 / 3.2 and PMI reports are standard with every shipment.
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