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ISO 9001:2015 · UNS N08800–N08810 · ASTM B408–B425

Incoloy Fasteners Manufacturer, Supplier & Exporter of Industrial Fasteners

Incoloy fasteners are nickel-iron-chromium alloy fasteners designed for high-temperature service and corrosion resistance in aggressive environments. We supply Incoloy 800, 800H, 800HT, 825 and 925 fasteners to petrochemical, nuclear, and chemical industries.
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5

Grades

30

Products

-29°C

Min Temp

1093°C

Max Temp

586 MPa

Min tensile strength · Incoloy 825 per ASTM B425

Very Good

High-temperature oxidation & carburization resistance

8.14 g/cm³

Density (avg) · Fe-Ni-Cr alloy

The high-temperature Fe-Ni-Cr alloy explained

What is Incoloy Fasteners?

Incoloy is a family of iron-nickel-chromium alloys containing 30–46% nickel and 19–23% chromium, engineered to combine the high-temperature oxidation resistance of nickel superalloys with the cost efficiency of iron-based construction. The alloy series — including Incoloy 800, 800H and 825 — serves two distinct service environments: high-temperature oxidizing and carburizing atmospheres (800 and 800H) and aqueous corrosion resistance in acid environments (825). Incoloy fasteners are specified for ethylene cracking furnace tube supports, steam reformer pigtails, nuclear steam generator hardware and sulfuric acid service where standard austenitic stainless steel is inadequate. Incoloy 825 (UNS N08825) with Mo 2.5–3.5% and Cu 1.5–3% is the most widely specified aqueous-service grade, while Incoloy 800H (UNS N08810) with controlled carbon and grain size is the standard for creep-limited high-temperature bolting above 600°C.
PropertySpecification
Base ElementIron-Nickel-Chromium
Ni Content30–46%
Cr Content19–23%
Max Service Temperature1093°C (800H)
Density7.94–8.14 g/cm³
ASTM StandardsB408, B425

Incoloy grades — which do you need?

Multiple fastener grades and material grades exist within Incoloy Fasteners, each tailored to specific industrial fasteners and engineering applications. Variations in mechanical properties, corrosion resistance, temperature capability, and strength influence material selection, so engineers should compare available grades to match operating environment, industry standards, and performance requirements.

Grade UNS Ni % Key Property Max Temp Best Application
Incoloy 825 (Most Popular) UNS N08825 38–46% Aqueous corrosion 540°C Oil wells, acids View grade
Incoloy 800 UNS N08800 30–35% Oxidation resistant 900°C Industrial furnaces View grade
Incoloy 800H UNS N08810 30–35% Creep resistant 1093°C Steam reformers View grade
Incoloy 800HT UNS N08811 30–35% High-temp strength 1100°C Heat treatment View grade
Incoloy 925 UNS N09925 42–46% High strength 650°C Offshore, oil & gas View grade
Incoloy 800
Incoloy 800H
Incoloy 800HT
Incoloy 825
Incoloy 925

Incoloy Fasteners — International Standards & Material Certifications

Incoloy Fasteners from RealBolt Engineering Industries are manufactured to ASME SB-408 (Incoloy 800/800H) and SB-425 (Incoloy 825) material standards. Nuclear service grades are supplied per ASME Section III; Incoloy 825 fasteners include NACE MR0175 documentation; all batches ship with EN 10204 MTC 3.1/3.2.
Standards
DIN 931 DIN 933 DIN 912 DIN 938 DIN 939 DIN 976-1 DIN 934 DIN 125A DIN 127 ISO 4014 ISO 4017 ISO 4762 ISO 4032 ASME B18.2.1 ASME B18.3 ASME B18.31.2 ASME B18.2.2 IS 1364 IS 1367
Certifications
ISO 9001:2015 NACE MR0175 NABL Lab PED 2014/68/EU MTC 3.1 / 3.2

Incoloy Fasteners Applications — Industries & Use Cases

Incoloy Fasteners from RealBolt Engineering Industries are specified by engineers and procurement teams across demanding industries where high-temperature oxidation, carburization resistance, and aqueous acid corrosion resistance for petrochemical and chemical service is critical to fastener performance and service life. Primary end-use sectors for Incoloy Fasteners include petrochemical cracking furnaces, chemical processing acid environments, nuclear steam generators, power generation boilers, and oil and gas — click each industry below to see specific application details and recommended grades.
Incoloy 800 and 800H fasteners are used in ethylene cracking furnace tube-support hardware, steam reformer pigtails and radiant section refractory anchors where temperatures exceed 900°C with carburizing atmospheres.
Incoloy 825 (UNS N08825) with Mo 2.5–3.5% and Cu 1.5–3% provides excellent resistance to sulfuric acid, phosphoric acid and reducing environments. Preferred for pickling tank internals, sulfuric acid coolers and chemical reactor flanges.
Incoloy 800 is used as a sheathing and support material in nuclear steam generators. Fasteners conform to ASME Section III requirements with full nuclear traceability.
Incoloy 800H with controlled carbon (0.05–0.10%) and grain size (ASTM 5 max) provides superior creep rupture strength for super-heater tube supports, HRSG fasteners and high-pressure steam header bolting.
Incoloy 825 tube and fasteners are used in sour crude oil tubing, downhole completion hardware and production Christmas trees where H₂S and CO₂ coexist with chloride-bearing brines.

Incoloy vs Inconel vs Stainless Steel

This comparison table helps petrochemical engineers and corrosion specialists evaluate Incoloy Fasteners against Inconel and Stainless Steel Fasteners based on maximum service temperature, high-temperature creep strength, sulfuric and phosphoric acid resistance, chloride SCC immunity, NACE MR0175 compliance, and relative material cost — for cracking furnaces, acid process plants, and nuclear service applications. Use this data to make an informed alloy selection for your specific operating environment, design code, and budget — or contact RealBolt’s technical team for a project-specific recommendation.
Property Incoloy 825 SS 317L Inconel 625
Sulfuric acid resistance Excellent Moderate Good
Max service temp 540°C 825°C 980°C
Chloride SCC resistance Excellent Low Excellent
Tensile strength (min) 586 MPa 515 MPa 758 MPa
Relative cost High Low Very High
NACE MR0175 compliant Yes Conditional Yes

Verdict: Incoloy 825 is the best-value solution for sulfuric acid, phosphoric acid and sour-well service where Inconel 625 is cost-prohibitive. SS 317L is adequate for mild acid service only.

Need Incoloy fasteners? Get a competitive price today.

Partner with RealBolt Engineering Industries for certified Incoloy Fasteners backed by full EN 10204 material test reports, competitive pricing, and reliable global delivery from our Mumbai facility. Our technical team supports Incoloy 800, 800H, 800HT, 825, and 925 Fasteners specification, supplying ASME Section III nuclear-traceable grades, NACE MR0175 Incoloy 825 fasteners, and custom-machined specials in sizes M12–M100 with EN 10204 3.1/3.2 documentation and NABL-accredited chemical and mechanical test reports. Request a quote today and receive a competitive price within 24 hours.
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Incoloy Fasteners — Common Questions Answered by Our Technical Team

Browse the expert answers below to the most frequently asked questions about Incoloy Fasteners — covering Incoloy 800 vs 800H selection, Incoloy 825 vs Inconel 825 naming clarification, carburization and oxidation service guidance, ASTM B408/B425 standards, NACE MR0175 for 825, nuclear traceability per ASME Section III, and available sizes with MTC 3.1/3.2 documentation. If your question is not answered here, contact the RealBolt technical team directly for grade-specific guidance, project support, and competitive pricing on Incoloy Fasteners.
Incoloy 800 (UNS N08800) has carbon 0.10% max and no grain size control. Incoloy 800H (UNS N08810) has controlled carbon (0.05–0.10%) and grain size (ASTM 5 or coarser) specifically to maximize creep rupture strength above 600°C. Choose 800H for continuous high-temperature service above 600°C where creep is the governing failure mode.
Incoloy 825 (UNS N08825) resists sulfuric acid at moderate temperatures and concentrations, phosphoric acid, seawater, reducing acids, and chloride SCC. The Mo (2.5–3.5%) + Cu (1.5–3%) additions provide significantly better acid resistance than SS 316L. It is widely used in sulfuric acid cooler fasteners, sour-well production tubing and nuclear waste handling.
Yes. Incoloy 800 and 800H have good resistance to carburization and nitriding environments up to 900°C and 1093°C respectively. Used in ethylene cracking furnace tube supports and radiant section hangers where carbon pickup from process gases would embrittle stainless steel fasteners.
The term ‘Inconel 825’ is a common misnomer. ‘Incoloy 825’ is the correct designation (registered trademark of Special Metals). Incoloy alloys are iron-nickel-chromium based (Ni 38–46%, Fe balance), while Inconel alloys are nickel-based (Ni 58%+ minimum). UNS N08825 is the correct designation for Incoloy 825.

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