Physical properties
| Density | 7.944 | g/cm³ |
Informative values: they vary with composition, condition and test method. Use the governing standard or measured mill data for pressure and heat-transfer calculations.
Chemical composition
Nominal: mid-range where both limits are given, the cap where only a maximum is, balance takes the remainder. Exact specified ranges below.
| Element | Name | Content % | |
|---|---|---|---|
| Main elements5 elements | |||
| Fe | Iron | ≥ 39.5% | |
| Ni | Nickel | 30 – 35% | |
| Cr | Chromium | 19 – 23% | |
| Al | Aluminium | 0.15 – 0.6% | |
| Ti | Titanium | 0.15 – 0.6% | |
| Element | Name | Content % | |
|---|---|---|---|
| Minor & residual6 elements | |||
| C | Carbon | ≤ 0.1% | |
| Mn | Manganese | ≤ 1.5% | |
| Si | Silicon | ≤ 1% | |
| Cu | Copper | ≤ 0.75% | |
| P | Phosphorus | ≤ 0.045% | |
| S | Sulphur | ≤ 0.015% | |
Mechanical minima by form
Guaranteed values differ by form, size and delivery condition; quotations confirm the specification, form, size and condition.
| Form | Condition | Rm MPa | Rp0.2 MPa | A ≥ % | Other requirements and notes |
|---|---|---|---|---|---|
| Bar and forgings | |||||
| Forgings | Annealed | ≥ 517 (75 ksi) | ≥ 207 (30 ksi) | ≥ 30 | |
| Bars and shapes (boiler and pressure-vessel use) | Annealed | ≥ 515 (75 ksi) | ≥ 205 (30 ksi) | ≥ 30 | Also specified: Hardness ≤ 192 HBW Hardness ≤192 HBW. |
| Rod and bar | Hot worked, as-hot-worked | ≥ 550 (80 ksi) | ≥ 240 (35 ksi) | ≥ 25 | Elongation ≥20% for hot-worked rectangular bar 7.94 mm and under. |
| Rod and bar | Cold-worked and hot-worked, annealed | ≥ 515 (75 ksi) | ≥ 205 (30 ksi) | ≥ 30 | |
| Forging quality bar | Forging quality | — | — | — | Forging quality: chemistry and surface only, no tensile requirement. |
| Bars and forgings (aerospace) | Hot finished and solution heat treated, dia. or least distance between parallel sides ≤102 mm | ≥ 448 (65 ksi) | ≥ 172 (25 ksi) | ≥ 30 | Bars shall not be cut from plate. Outside the standard size range, by agreement. |
| Plate, sheet and strip | |||||
| Plate, sheet and strip | Annealed | ≥ 520 (75 ksi) | ≥ 205 (30 ksi) | ≥ 30 | |
| Hot-rolled plate | As-rolled | ≥ 550 (80 ksi) | ≥ 240 (35 ksi) | ≥ 25 | |
| Tube and pipe | |||||
| Seamless pipe and tube | Cold-worked, then annealed | ≥ 520 (75 ksi) | ≥ 205 (30 ksi) | ≥ 30 | |
| Seamless pipe and tube | Hot finished and annealed, or as hot finished | ≥ 450 (65 ksi) | ≥ 170 (25 ksi) | ≥ 30 | |
| Welded pipe (no filler metal) | Annealed | ≥ 520 (75 ksi) | ≥ 207 (30 ksi) | ≥ 30 | Flattening test required. Every piece is leak- or electrically tested (hydrostatic, pneumatic, eddy current or ultrasonic). |
| Welded tube | Annealed | ≥ 520 (75 ksi) | ≥ 205 (30 ksi) | ≥ 30 | Flattening and flange tests required. Every piece is leak- or electrically tested (hydrostatic, pneumatic, eddy current or ultrasonic). |
| Fittings and flanges | |||||
| Fittings (factory-made wrought butt-weld / socket) | 1800-1900 °F [983-1038 °C], rapid air or water quench | — | — | — | Recommended temperature; tolerance ±15 °C (±25 °F). Tensile properties follow the starting material. No tension test on the finished fitting unless agreed. Heat treatment depends on the service temperature; agreed with the producer. |
| Fittings (wrought austenitic stainless, butt-weld / socket) | Solution annealed 1800–1900 °F [982–1038 °C], water quenched or otherwise rapidly cooled | ≥ 450 (65 ksi) | ≥ 170 (25 ksi) | ≥ 28 | Elongation: ≥28% longitudinal, ≥20% transverse. A single temperature is a minimum. All fittings are supplied heat-treated. Heat treatment depends on the service temperature; agreed with the producer. |
| Several forms | |||||
| Flat products ≤75 mm and bars ≤160 mm (EN 10095, 1.4876) | +AT (solution annealed) | 450 – 680 | ≥ 170 | ≥ 30 | Rp1.0 ≥ 210 MPa; flat products under 3 mm: A ≥ 28 %. |
Hardness requirement
Required by the standard, conditionally
| Form and thickness | Rockwell B hardness, max |
|---|---|
| Sheet ≤1.3 mm (width ≤1.42 m) | ≤ 86 HRB |
| Sheet 1.3 – 6.4 mm | ≤ 86 HRB |
| Strip 0.13 – 0.25 mm (width ≤305 mm) | ≤ 88 HRB |
| Strip 0.25 – 3.2 mm | ≤ 86 HRB |
Applies to deep-drawing / spinning quality only, accepted together with grain size; that quality is not subject to the ordinary tensile minima.
More detail 1
Below 0.050 in. (1.3 mm) the standard recommends superficial Rockwell or Vickers instead, since Rockwell readings on thin material are affected by specimen thickness.
Creep behaviour
Guidance values (MPa) — Mean values of a scatter band. They are neither an acceptance requirement nor a design allowable stress. Figures in parentheses are long-term extrapolations and less reliable than the tested range.
| Temp °C | Creep strength Rp1.0 (1% plastic strain) | Rupture strength Ru | ||
|---|---|---|---|---|
| 10 000 h | 1 000 h | 10 000 h | 100 000 h | |
| 600 | 90 | 200 | 152 | 114 |
| 700 | 40 | 90 | 68 | 48 |
| 800 | 15 | 45 | 30 | 21 |
| 900 | 5 | 20 | 10 | 8 |
The table above is for the +AT (solution-annealed) condition (W.Nr. 1.4876 X10NiCrAlTi32-21).
Rp1.0 is the stress producing 1 % plastic elongation and Ru the stress to rupture; at the same temperature and time Rp1.0 is necessarily below Ru. Design deflection-sensitive parts to Rp1.0 and design to fracture with Ru.
1 000 h strength for 1 % elongation: 130 MPa at 600 °C, 70 at 700 °C, 30 at 800 °C and 13 at 900 °C. (The table above lists Rp1.0 at 10 000 h and 100 000 h only.)
⚠ At 100 000 h there is rupture strength only, with no 1 % elongation strength. Controlling long-term deformation needs a manufacturer's creep curve.
⚠ EN 1.4876 is specified as C ≤0.12, Cr 19-23, Ni 30-34, Al 0.15-0.60, Ti 0.15-0.60, essentially the same window as ASTM N08800 (whose Ni ceiling is 35 and carbon ceiling 0.10). But EN 1.4876 has neither a carbon minimum nor a coarse-grain requirement — and those are precisely the two extra requirements that distinguish N08810 (800H) and N08811 (800HT) from N08800. The table above therefore represents Alloy 800-level creep behaviour.
⚠ The maximum application temperature in air, Tₐ = 1 100 °C, is an oxidation criterion (defined by scaling loss), not a load-bearing one. Set it against the table above: at 900 °C and 100 000 h the rupture strength is 8 MPa.
Grain size
Required by the standard, conditionally
| Form and thickness | ASTM micrograin size | Mean grain diameter, max |
|---|---|---|
| Sheet ≤1.3 mm (width ≤1.42 m) | No. 4.5 or finer | 0.075 mm |
| Sheet 1.3 – 6.4 mm | No. 3.5 or finer | 0.110 mm |
| Strip 0.13 – 0.25 mm (width ≤305 mm) | No. 8 or finer | 0.022 mm |
| Strip 0.25 – 3.2 mm | No. 4.5 or finer | 0.075 mm |
Only deep-drawing / spinning quality cold-rolled sheet and strip must meet these grain size and hardness limits; that quality is not subject to the ordinary tensile minima.
More detail 1
No grain-size requirement applies to the other product forms.
Where this grade is recommended
Matched in 2 service conditions; ranks and scores computed from the condition-scoring matrix.
| Service condition | Industry | Temperature | Rank | Score |
|---|---|---|---|---|
| Nuclear SG tubing | Power & Nuclear | ≤ 300 °C | 3 / 4 | 86 |
| Hydroprocessing & refinery hot service | Oil & Gas | 250 – 400 °C | 7 / 8 | 84 |
Designations & equivalents
| W.Nr. (Germany) | 1.4876 |
| EN designation | X10NiCrAlTi32-21 |
| Trade name(s) | Incoloy 800 |
| ASTM / AISI | A182 / A240 / A276 / A403 / A479 / B163 / B366 / B407 / B408 / B409 / B514 / B515 / B564 / B751 / B775 / B829 / B906 |
| AMS (SAE aerospace) | 5766 / 5871 |
| BS (UK) | NA15 (BS 3072/3073/3074/3075/3076) |
| JIS (Japan) | NCF800 |
| GOST (Russia) | ≈ ХН32Т (ЭП670) |
Cross-references are common near-equivalents for search and shortlisting; substitution across standards requires clause-by-clause verification. All grades in one cross-reference table →
Applicable standards
13 specifications. Name the standard and its edition on the order.
Guaranteed values and required tests differ between specifications — see Mechanical minima by form for the figures per form.
Frequently asked questions
What is Alloy 800 · UNS N08800?
Alloy 800 · UNS N08800 — Fe-Ni superalloys. Fe-Ni-Cr general heat-resistant — heat exchangers and furnace tubes
What is the maximum service temperature of N08800?
Typically about 800 °C; the practical limit depends on media, stress and design life — acceptance per the governing standard.
What is the tensile strength of N08800?
The specified minimum tensile strength is 520 MPa for the main product form. Minima for other forms and sizes are listed under "Mechanical minima by form" on this page.
Which standards cover N08800?
ASTM A182, ASTM A403, ASTM A479, ASTM B407, ASTM B408, ASTM B409, ASTM B514, ASTM B515, ASTM B564 (forgings), ASTM B906, AMS 5766, AMS 5871, EN 10095 (heat-resisting steels and nickel alloys)
Where is N08800 typically used?
Nuclear SG tubing (Power & Nuclear); Hydroprocessing & refinery hot service (Oil & Gas)
In which forms is N08800 available?
Tube, plate, strip, bar, forgings, wire and other forms — sizes and delivery condition confirmed per order, with EN 10204 3.1 / 3.2 certification.
Same series
Download PDF datasheet
This grade’s datasheet as an A4 PDF — for filing, printing or forwarding to colleagues.
Download PDF datasheetSupply & enquiry
Tube & pipeφ1 – 219 × 0.25 – 25 mm
Plate4.76 – 80 mm
Barφ8 – 300 mm
Wire & filler metalsφ0.01 – 8 mmFor this grade we can supply, against your service conditions:
- Tube, plate, strip, bar, forgings, wire and more — with size range and lead time
- Chemistry and mechanical test report (EN 10204 3.1 / 3.2)
- Like-for-like alternatives and selection advice
- Applicable standards and inspection scope
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