Incoloy Flanges
Giriraj Impex is a manufacturer, stockist, supplier and exporter of Incoloy flanges in Incoloy 800 (UNS N08800), 800H (N08810), 800HT (N08811) and 825 (N08825). We manufacture Incoloy flanges from ASTM B564 / ASME SB564 forgings to ASME B16.5 from ½" to 24" NB in Class 150 to 2500, to ASME B16.47 for larger sizes, and to EN 1092-1, in weld neck, slip-on, blind, socket weld, threaded, lap joint and orifice types, with mill test certificates.
Incoloy 800H flanges are used in high-temperature reformer, cracker and furnace piping, and Incoloy 825 flanges in acid, chloride and sour-gas piping, matching Incoloy pipe and fittings.
Specifications
| Item | Details |
|---|---|
| Material | ASTM B564 / ASME SB564 – N08800, N08810, N08811, N08825 |
| Dimensional standards | ASME B16.5, B16.47 Series A and B, B16.36, B16.48; EN 1092-1 |
| Sizes | ½" to 24" NB (B16.5); larger to B16.47 |
| Classes | 150, 300, 600, 900, 1500, 2500; PN ratings to EN 1092-1 |
| Types | Weld neck, slip-on, blind, socket weld, threaded, lap joint, long weld neck, orifice, reducing, spectacle blind |
| Facings | RF, FF, RTJ |
| Condition | 800 annealed; 800H / 800HT solution annealed; 825 annealed |
| Documents | Mill test certificate (MTC); third-party inspection on request |
Chemical composition and mechanical properties
| Alloy | Ni | Cr | Fe | C | Mo | Cu | Al | Ti | Mn | Si | S |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 800 (N08800) | 30.0–35.0 | 19.0–23.0 | 39.5 min | 0.10 | – | 0.75 | 0.15–0.60 | 0.15–0.60 | 1.5 | 1.0 | 0.015 |
| 800H (N08810) | 30.0–35.0 | 19.0–23.0 | 39.5 min | 0.05–0.10 | – | 0.75 | 0.15–0.60 | 0.15–0.60 | 1.5 | 1.0 | 0.015 |
| 800HT (N08811) | 30.0–35.0 | 19.0–23.0 | 39.5 min | 0.06–0.10 | – | 0.75 | 0.15–0.60 | 0.15–0.60 | 1.5 | 1.0 | 0.015 |
| 825 (N08825) | 38.0–46.0 | 19.5–23.5 | 22.0 min | 0.05 | 2.5–3.5 | 1.5–3.0 | 0.2 | 0.6–1.2 | 1.0 | 0.5 | 0.03 |
Alloy 800HT also requires Al + Ti 0.85–1.20%. Alloys 800H and 800HT have grain size and heat-treatment requirements for elevated-temperature service, as given in the standards.
| Alloy and condition | Tensile strength, MPa (ksi) | Yield strength 0.2%, MPa (ksi) | Elongation, % |
|---|---|---|---|
| 800 (N08800), annealed | 517 (75) | 207 (30) | 30 |
| 800H / 800HT (N08810 / N08811), solution annealed | 448 (65) | 172 (25) | 30 |
| 825 (N08825), annealed | 586 (85) | 241 (35) | 30 |
Values common to ASTM B407, B409 and B408 (alloy 800 family), B423, B424 and B425 (alloy 825) and B564 forgings; check the standard for the product form and size.
Background and equivalents are on the Incoloy page.
Pressure ratings
ASME B16.5 includes Incoloy 800, 800H and 825 forgings in its nickel alloy material groups, with pressure-temperature ratings for each class. At high temperatures, the 800H ratings reflect its creep strength, which is why 800H flanges are chosen over alloy 800 or stainless steel for reformer and furnace piping. The rating should always be taken from the B16.5 table for the actual material group and design temperature, and the joint designed with bolting and gaskets suited to that temperature.
800H or 825 flanges?
Incoloy 800H and 800HT flanges are used where the line runs hot – reformer outlet systems, hydrogen and syngas transfer lines, cracking furnace piping and power plant headers – and must match the creep strength and expansion of 800H pipe. Incoloy 800 flanges suit lower-temperature heat-exchanger and process piping. Incoloy 825 flanges are used where corrosion is the concern rather than temperature: sulphuric and phosphoric acid lines, seawater-cooled systems, pollution control and sour oil and gas service.
How we manufacture Incoloy flanges
Incoloy flanges are machined from forged blanks or rings of certified material that have been forged to shape and annealed or solution annealed. For 800H and 800HT, the solution anneal produces the coarse grain size needed for creep strength. Machining covers the bore, facing, hub, flange thickness and bolt holes to ASME B16.5 or the specified standard, with a serrated or smooth face finish as ordered. Every flange is marked with alloy, specification, size, class, facing and heat number, and inspected for dimensions and finish before dispatch.
Bolting and gaskets for hot service
For 800H flanges at high temperature, bolting must keep its preload as the joint heats up. Alloy steel B16 or nickel alloy studs such as Inconel 718 are often specified, and the thermal expansion of the bolting is considered against that of the flange. Gaskets are typically spiral-wound with an Incoloy or Inconel winding and a graphite or mica filler suited to the temperature, or RTJ rings in a suitable alloy. For 825 flanges in corrosive service, PTFE-based or spiral-wound gaskets with compatible materials are used.
Ordering Incoloy flanges
Please give the alloy, flange type, size, class, facing and face finish, bore or pipe schedule for weld neck and socket weld flanges, quantity and any testing such as ultrasonic, dye penetrant, grain size or positive material identification, or third-party inspection. Flanges are packed in wooden boxes with faces protected.
Applications and related products
Incoloy flanges are used in hydrogen and ammonia reformers, ethylene crackers, furnace and transfer-line piping, power plant headers, acid plants, seawater-cooled systems and sour gas service. Matching products include Incoloy pipes and tubes, Incoloy pipe fittings, Incoloy sheets and plates, Incoloy round bars and Incoloy fasteners. Flanges in other materials are on the flanges page.
Frequently Asked Questions
Incoloy flanges are made from forgings to ASTM B564 (ASME SB564), with dimensions to ASME B16.5, B16.47 or EN 1092-1.
800H has the creep strength and oxidation resistance needed above about 600 °C, and matches the 800H pipe used in reformer outlet systems.
800H flanges are for high-temperature service where creep strength matters; 825 flanges are for corrosive acid, chloride and sour service at lower temperatures.
Alloy steel B16 or nickel alloy studs such as Inconel 718 are often specified so the joint keeps its preload at high temperature.
Weld neck, slip-on, blind, socket weld, threaded, lap joint, long weld neck, orifice, reducing flanges and spectacle blinds.
Yes. Incoloy 825 flanges can be supplied to NACE MR0175 / ISO 15156 on request.
Request a Quote for Incoloy Flanges
Tell us the product, grade, size, standard, quantity and delivery location, and our sales team will reply with a quotation.
Inconel® and Incoloy® are trademarks of Special Metals Corporation.