Incoloy 800 / 800H / 800HT FastenersUNS N08800 · Manufacturer, trader & exporter, India
Also sold as Alloy 800 · UNS N08800 / N08810 / N08811 · W.Nr 1.4876 · Incoloy 800H
Incoloy 800 / 800H / 800HT fasteners — stud bolts, hex bolts, nuts and washers — available in this alloy. May be machined from ASTM B408 bar (UNS N08800), where applicable; finished fastener requirements are to the purchase specification or project drawing. Dimensions to ASME B18 where applicable, or your drawing. State the finished fastener specification your project requires on the order. It is a nickel–iron–chromium alloy for high-temperature service, chosen for furnaces, petrochemical heaters and high-temperature piping. Kanak Steel & Engineering Co. manufactures, trades and exports it from Mumbai; EN 10204 3.1 or 3.2 certificates are available on request / as specified in the PO. Markets we have supplied to include Oman, UAE, Saudi Arabia, Brazil, Argentina, Spain and Chile (India is the home market).
- Stock & mill supply
- EN 10204 3.1 / 3.2
- PMI on request
- Export packing
Reviewed by the Kanak Steel & Engineering Co. technical team · Updated October 2026
What is Incoloy 800 / 800H / 800HT Fasteners?
Incoloy 800 / 800H / 800HT fasteners is a nickel–iron–chromium alloy for high-temperature service supplied as fasteners (UNS N08800). May be machined from ASTM B408 bar (UNS N08800), where applicable; finished fastener requirements are to the purchase specification or project drawing. Buyers specify it for furnaces, petrochemical heaters and high-temperature piping. It is also sold as Alloy 800, UNS N08800 / N08810 / N08811, W.Nr 1.4876.
- What it is
- Nickel–iron–chromium alloy for high-temperature service
- Material
- May be machined from ASTM B408 bar (UNS N08800), where applicable; finished fastener requirements are to the purchase specification or project drawing
- Feedstock (bar)
- ASTM B408, where applicable
- Dimensions
- ASME B18.2.1 · B18.2.2 · B18.31.2
- Threads
- UNC · UN-8 · metric
- Sizes
- M10 – M64 · ½" – 4"
- Best at
- Furnaces, petrochemical heaters and high-temperature piping
Incoloy 800 / 800H / 800HT Fasteners Specification & Sizes
| Material | May be machined from ASTM B408 bar (UNS N08800), where applicable; finished fastener requirements are to the purchase specification or project drawing |
|---|---|
| Material / feedstock | ASTM B408 — a bar specification, where applicable; it covers the bar, not the finished fastener |
| Manufacturing route | By type: bolts, studs, cap screws and nuts may be machined from bar, where applicable; threaded rod, U-bolts, eye bolts, anchor and foundation bolts are route-dependent; washers not asserted — all to the purchase specification or project drawing |
| Dimensional standards | ASME B18.2.1 (bolts) · B18.2.2 (nuts) · B18.31.2 (studs) · DIN 931 / 933 / 934 (legacy DIN) |
| Types | Stud bolt · Hex bolt · Heavy hex nut · Hex nut · Washer · Threaded rod · U-bolt · Eye bolt · Anchor bolt · Foundation bolt · Socket head cap screw · Machine screw |
| Threads | UNC, UN-8 and metric coarse |
| Coating | Plain · PTFE on request |
| Documents | EN 10204 3.1 |
Incoloy 800 / 800H / 800HT Stud Bolts: Grade & Nut Pairing
Incoloy 800 / 800H / 800HT studs and nuts may be machined from ASTM B408 bar, where applicable; the finished fastener specification is to the purchase specification or project drawing, and the nut is usually the same alloy.
Torque (T = K × F × d), stud length and coatings are covered in the fasteners guide.
| Galling | Stainless and nickel-alloy threads gall — always use anti-seize, and avoid high-speed tightening |
|---|---|
| Coatings | Usually supplied plain; PTFE coating on request to ease tightening |
| Marking | Grade symbol and maker's mark on each stud end and nut, as the standard requires |
| Certificates | EN 10204 3.1 for the bar heat; mechanical test reports on the finished bolts on request |
Incoloy 800 / 800H / 800HT Fasteners Chemical Composition
Under technical review for TDS.
| Element | Current requirement |
|---|---|
| Nickel | As specified |
| Chromium | As specified |
| Iron | As specified |
| Carbon | As specified |
| Aluminium | As specified |
| Titanium | As specified |
| Copper | As specified |
| Manganese | As specified |
| Silicon | As specified |
Numerical specification requirements are published only after the applicable current standard edition has been verified. Governing specification to be verified: ASTM B409 for UNS N08800 / N08810.
Incoloy 800 / 800H / 800HT Fasteners Mechanical Properties
Under technical review for TDS.
| Property | Current requirement |
|---|---|
| Tensile strength | As specified |
| Yield strength 0.2% | As specified |
| Elongation | As specified |
Numerical specification requirements are published only after the applicable current standard edition has been verified. Governing specification and condition to be verified: ASTM B409 for UNS N08800 / N08810 — Annealed plate.
Density & Physical Properties
| Property | Value |
|---|---|
| Density | 7.94 g/cm³ |
| Melting range | 1357 – 1385 °C |
| Magnetic | Non-magnetic |
Incoloy 800 / 800H / 800HT Equivalent Grades
Six-digit Harmonized System heading (iron and steel, chapter 72–73). Your country adds its own digits — confirm with your customs broker. All HS codes.
How to Verify Incoloy 800 / 800H / 800HT Fasteners with PMI
Positive material identification with a handheld XRF gun confirms the alloy on the piece itself, in seconds, before it is cut or welded. Incoloy 800 / 800H / 800HT is most often mixed up with Inconel 825 — the table shows which elements tell them apart.
Handheld XRF does not measure carbon or nitrogen; those come from the mill certificate or optical emission (OES) testing. PMI can be arranged on request — state it on your enquiry.
Under technical review for TDS.
| Element | Incoloy 800 / 800H / 800HT | Inconel 825 |
|---|---|---|
| Nickel | As specified | As specified |
| Chromium | As specified | As specified |
| Molybdenum | — | As specified |
| Copper | As specified | As specified |
| Titanium | As specified | As specified |
| Iron | As specified | As specified |
| Manganese | As specified | As specified |
Incoloy 800 / 800H / 800HT fasteners by type
Incoloy 800 / 800H / 800HT Fasteners Applications
Incoloy 800 / 800H / 800HT is specified when the cheaper grade will not survive the service but a higher alloy would be more than the job needs. These are the jobs our buyers use it for.
Incoloy 800 / 800H / 800HT Fasteners vs 310S, 600 and 825
| Grade | Fasteners standard | PREN (approx.) | Pick it when |
|---|---|---|---|
| Inconel 600 | May be machined from ASTM B166 bar (UNS N06600), where applicable; finished fastener requirements are to the purchase specification or project drawing | — | High-temperature oxidation, caustic and nuclear service |
| Incoloy 800 / 800H / 800HT | May be machined from ASTM B408 bar (UNS N08800), where applicable; finished fastener requirements are to the purchase specification or project drawing | — | Furnaces, petrochemical heaters and high-temperature piping |
| SS 310 / 310S | May be machined from ASTM A276 / A479 bar (UNS S31008), where applicable; finished fastener requirements are to the purchase specification or project drawing | ≈ 25 | Furnaces, burners and heat treatment at high temperature |
| Inconel 825 | May be machined from ASTM B425 bar (UNS N08825), where applicable; finished fastener requirements are to the purchase specification or project drawing | ≈ 31 | Sulphuric and phosphoric acid service, chloride stress-corrosion cracking |
PREN = Cr + 3.3 Mo + 16 N, from mid-range chemistry. A screening guide, not a substitute for corrosion data on your medium.
Incoloy 800 / 800H / 800HT Corrosion Resistance — Element by Element
Each alloying addition has a job. Knowing which one protects against your medium is the quickest way to judge whether 800 fits.
Balanced nickel and chromium resist oxidation and carburisation in furnace atmospheres.
Controlled carbon and coarse grain give 800H/HT their creep-rupture strength above 600 °C.
Aluminium and titanium improve high-temperature strength.
For aqueous acid service choose 825 instead.
How your 800 fasteners order runs
- 01Enquiry review — we confirm size, standard edition and documents against your MR or drawing.
- 02Heat selection & PMI — the mill certificate is checked against your order; PMI can be arranged depending on product and requirements, as specified in the PO.
- 03Processing — cutting, machining or bevelling to your specification, with heat numbers marked as specified in the PO.
- 04Inspection — your third-party inspector witnesses, or we share photos and test reports.
- 05Packing & dispatch — seaworthy packing from Nhava Sheva (JNPT), Mumbai, FOB or CIF, documents sent before the vessel sails.
Standards on this page
Welding & Fabricating Incoloy 800 / 800H / 800HT Fasteners
Incoloy 800 / 800H / 800HT welds by all common arc processes. A few points our buyers ask about:
| Matching filler | ERNiCr-3 (AWS A5.14) |
|---|---|
| Over-alloyed filler | ERNiCrCoMo-1 for creep-critical joints |
| Preheat | Not required; keep interpass temperature low |
| Cutting | Thermal or abrasive cutting; grind off heat-tinted edges before welding |
Follow your approved WPS; this is general guidance. See also 800 fittings and 800 flanges for the matching pipe-system parts.
How to Order Incoloy 800 / 800H / 800HT Fasteners: RFQ Checklist
Get an accurate quote the first time. Copy this list into your enquiry:
- Fastener type, size and length
- Thread form
- Material and marking
- Quantity in sets
- Certificate type
- Delivery port and date
Incoloy 800 / 800H / 800HT fasteners — questions buyers ask
Is Incoloy 800 / 800H / 800HT the same as Alloy 800?
Alloy 800, UNS N08800 / N08810 / N08811, W.Nr 1.4876 are names used for Incoloy 800 / 800H / 800HT (W.Nr / EN numbers and older UNS variants are the closest designations; their limits can differ slightly, so specify the UNS number and ASTM grade on the order). Whichever name is on the enquiry, fasteners: may be machined from ASTM B408 bar (UNS N08800), where applicable.
Why use Incoloy 800 / 800H / 800HT bolts instead of B7 carbon steel?
On Incoloy 800 / 800H / 800HT flanges in corrosive service, carbon-steel bolts corrode first. Matching-alloy bolting avoids galvanic corrosion and bolt failure.
What nut goes with Incoloy 800 / 800H / 800HT stud bolts?
Usually a heavy hex nut in the same Incoloy 800 / 800H / 800HT alloy — it may be machined from ASTM B408 bar, where applicable; finished requirements are to the purchase specification or project drawing.
How do I stop Incoloy 800 / 800H / 800HT bolts galling?
Use an anti-seize compound on threads and nut faces, tighten at moderate speed, and do not reuse galled nuts.
Incoloy 800 / 800H / 800HT or Inconel 825 — which should I choose?
Incoloy 800 / 800H / 800HT is chosen for furnaces, petrochemical heaters and high-temperature piping. Inconel 825 is the step up when you need more pitting resistance or strength. See the comparison table on this page, or ask us with your process conditions.
Sources: the ASTM / ASME specifications named on this page and producer datasheets · Last updated October 2026