Incoloy 800 / 800H / 800HT (UNS N08800 / N08810 / N08811)
The economical high-temperature alloy — 32 % nickel, 21 % chromium — for furnace, reformer and heat-exchanger hardware from 1000 to 1800 °F.
What Incoloy 800 is.
Incoloy 800 is an iron-based alloy with about 32 percent nickel and 21 percent chromium. It resists oxidation and carburisation at high temperature and chloride stress-corrosion cracking at low temperature, at a lower cost than the nickel-based Inconels. Alloy 800H holds carbon between 0.05 and 0.10 percent with a coarse grain for creep strength above 1100 °F; 800HT adds a controlled aluminum-plus-titanium content for the highest creep-rupture strength.
ASTM B408 covers all three in bar. We machine Incoloy 800-series studs, bolts and components from certified B408 bar.
Chemical composition.
| Element | Symbol | Min % | Max % |
|---|---|---|---|
| Nickel | Ni | 30.0 | 35.0 |
| Chromium | Cr | 19.0 | 23.0 |
| Iron | Fe | 39.5 | — |
| Manganese | Mn | — | 1.5 |
| Carbon | C | — | 0.10 |
| Copper | Cu | — | 0.75 |
| Silicon | Si | — | 1.0 |
| Sulfur | S | — | 0.015 |
| Aluminum | Al | 0.15 | 0.60 |
| Titanium | Ti | 0.15 | 0.60 |
| Phosphorus | P | — | 0.045 |
Values per ASTM B408-22 Table 6 (verified against the specification). Confirm the edition called out on your purchase order with our estimating team. 800H: carbon 0.05–0.10 %. 800HT: carbon 0.06–0.10 %, Al 0.25–0.60, Ti 0.25–0.60, Al + Ti 0.85–1.20 %.
Mechanical properties.
| Condition and size | Tensile strength, min (ksi) | Yield strength 0.2%, min (ksi) | Elongation, min (%) |
|---|---|---|---|
| N08800 — hot worked, as hot worked | 80 | 35 | 25 |
| N08800 — cold or hot worked, annealed | 75 | 30 | 30 |
| N08810 (800H) and N08811 (800HT) — annealed | 65 | 25 | 30 |
Values per ASTM B408-22 Table 5 (verified against the specification). Confirm the edition called out on your purchase order with our estimating team.
Specifications that apply.
How Incoloy 800 ships from Houston.
- Full-thread studs and stud bolts
- Hex and heavy hex bolts
- Socket head cap screws
- Hex nuts in the same alloy
- Threaded rod
- Machined components from certified bar
Incoloy 800 fasteners we make.
Every item is manufactured to your drawing or standard in Incoloy 800, imperial or metric, with an EN 10204 3.1 certificate.
800, 800H or 800HT?
The three alloys share one chemistry with tighter controls in the H and HT versions. Alloy 800 is the general grade for service below about 1100 °F, where fine grain gives the best strength and toughness. 800H restricts carbon to 0.05 to 0.10 percent and is solution annealed to a coarse grain, which raises creep-rupture strength above 1100 °F. 800HT adds a minimum aluminum-plus-titanium of 0.85 percent for the highest creep strength and is the grade written into most modern reformer and furnace specifications. The bar minimums are lower for 800H and 800HT because coarse-grained material is softer at room temperature.
Testing, certification and marking
- Tensile and hardness tested per lot on the finished product
- Grade or alloy marking 800, 800H or 800HT with heat number and manufacturer's identification on every piece
- EN 10204 3.1 material test report with heat number and chemistry; 3.2 witness available
Inconel 600 (UNS N06600)
The general-purpose nickel-chromium alloy — oxidation resistant to 2000 °F, immune to chloride stress-corrosion cracking, for furnace, heat-treat and nuclear hardware.
ASTM A453 / ASME SA-453ASTM A453 Grade 660 (A-286)
A-286 bolting for the hottest joints — 130 ksi at room temperature and rated by stress-rupture at 1200 °F, for gas and steam turbines, exhaust and high-temperature process equipment.
ASTM B446 bar · ASTM F468 / F467 fastenersInconel 625 (UNS N06625)
The corrosion all-rounder — 120 ksi in the annealed condition, resistant to seawater, sour gas, acids and oxidation to 1800 °F, and the F468 nickel fastener grade Ni 625.