Seamless rolled rings
Radial-axial ring rolled from a pierced and upset billet, giving continuous circumferential grain flow.
OD 200-3,000 mm, wall 20-400 mm, height 20-800 mmDefinition
What is Alloy 800H?
Alloy 800H (UNS N08810) is a nickel-iron-chromium alloy containing 30.0 to 35.0 % nickel, 19.0 to 23.0 % chromium and a minimum of 39.5 % iron, with carbon controlled to 0.05 to 0.10 % and an ASTM grain size of 5 or coarser. These two controls separate the H grade from standard Alloy 800. They raise creep and stress-rupture strength at temperatures above about 600 °C (1100 °F) while keeping the same resistance to oxidation, carburisation and chloride stress-corrosion cracking.
The alloy is also sold as Incoloy 800H and Nicrofer 3220 H. In Europe it carries the designation W.Nr. 1.4958 (X5NiCrAlTi31-20) under DIN 17460. Because the composition ranges of 800H and 800HT overlap, most of the forgings we ship are dual certified to 800H/800HT (N08810/N08811), which is what reformer and cracking furnace specifications normally call for.
Alloy 800H is not a precipitation-hardening alloy. It is supplied in the solution-annealed condition, and its high-temperature strength comes from the coarse grain structure and carbide distribution rather than from an ageing treatment.
Reviewed 13 August 2026 by the technical sales department, Jiangyin Jiangnan Metal Co., Ltd.
N08800 / N08810 / N08811
Alloy 800 vs 800H vs 800HT
The three grades share the same nickel-iron-chromium base and differ in carbon content, combined aluminium plus titanium level, grain size and annealing temperature. Alloy 800 covers service below 600 °C. Alloy 800H covers service above 600 °C where creep governs. Alloy 800HT is specified where the design calls for the highest and most consistent stress-rupture life.
| Property | Alloy 800 (N08800) | Alloy 800H (N08810) | Alloy 800HT (N08811) |
|---|---|---|---|
| Carbon, % | 0.10 max | 0.05 to 0.10 | 0.06 to 0.10 |
| Aluminium plus titanium, % | Not specified | 0.30 to 1.20 | 0.85 to 1.20 |
| Grain size | Not specified | ASTM 5 or coarser | ASTM 5 or coarser |
| Anneal temperature | About 980 °C min | 1121 °C (2050 °F) min | 1121 °C (2050 °F) min |
| Service range | Up to about 600 °C | Above 600 °C, creep limited | Above 600 °C, creep limited |
| Relative rupture strength | Baseline | High | Highest |
| Typical use | Process piping, heat exchangers, general corrosion service | Reformer manifolds, furnace retorts, superheater components | Pyrolysis and reformer parts with the longest design life |
A single heat can satisfy both Alloy 800 and Alloy 800H, but only if it also meets the grain size and annealing temperature requirements. Ask for dual certification at the enquiry stage rather than after the forging has been annealed.
ASTM B564, weight percent
Chemical composition of UNS N08810
Alloy 800H contains 30.0 to 35.0 % Ni, 19.0 to 23.0 % Cr, 39.5 % Fe minimum, 0.05 to 0.10 % C, 0.15 to 0.60 % Al, 0.15 to 0.60 % Ti with Al plus Ti of 0.30 to 1.20 %, together with 1.5 % Mn max, 1.0 % Si max, 0.75 % Cu max and 0.015 % S max.
| Grade | Ni | Cr | Fe | C | Al | Ti | Al+Ti | Mn | Si | Cu | S |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 800H | 30.0-35.0 | 19.0-23.0 | 39.5 min | 0.05-0.10 | 0.15-0.60 | 0.15-0.60 | 0.30-1.20 | 1.5 max | 1.0 max | 0.75 max | 0.015 max |
| 800HT | 30.0-35.0 | 19.0-23.0 | 39.5 min | 0.06-0.10 | 0.25-0.60 | 0.25-0.60 | 0.85-1.20 | 1.5 max | 1.0 max | 0.75 max | 0.015 max |
Iron is the balance element and is reported rather than aimed at. Every heat is checked by optical emission spectrometry before the billet is cut, and the result is printed on the EN 10204 certificate against the heat number stamped on the part.
Solution annealed, room temperature
Mechanical properties
ASTM B564 requires solution-annealed Alloy 800H forgings to reach a minimum tensile strength of 450 MPa (65 ksi), a minimum 0.2 % yield strength of 170 MPa (25 ksi) and a minimum elongation of 30 %. Values from our own production normally sit well above these minima.
| Property | ASTM B564 minimum | Typical as forged and annealed |
|---|---|---|
| Tensile strength | 450 MPa / 65 ksi | 520-690 MPa / 75-100 ksi |
| Yield strength, 0.2 % offset | 170 MPa / 25 ksi | 205-415 MPa / 30-60 ksi |
| Elongation in 4D | 30 % | 35-55 % |
| Reduction of area | Not specified | 50-70 % |
| Hardness | Not specified | 120-184 HB |
| Grain size, ASTM E112 | No. 5 or coarser | No. 3 to 5 |
Test coupons are taken from prolongations that receive the same heat treatment as the forging. Tensile testing follows ASTM E8/E8M and grain size follows ASTM E112. Intergranular corrosion testing to ASTM A262 Practice E is carried out where the enquiry calls for it.
Annealed condition
Physical properties
| Property | Metric | Imperial |
|---|---|---|
| Density | 7.94 g/cm³ | 0.287 lb/in³ |
| Melting range | 1357-1385 °C | 2475-2525 °F |
| Modulus of elasticity | 196.5 GPa | 28.5 x 10³ ksi |
| Specific heat | 460 J/kg·K | 0.11 Btu/lb·°F |
| Thermal conductivity | 11.5 W/m·K | 80 Btu·in/ft²·h·°F |
| Mean thermal expansion, 20-100 °C | 14.4 µm/m·K | 8.0 µin/in·°F |
| Electrical resistivity | 0.989 µΩ·m | 595 Ω·circ mil/ft |
| Magnetic permeability at 200 Oe | About 1.010, effectively non-magnetic at room temperature | |
Indicative data
Creep and stress-rupture strength
Alloy 800H is chosen over Alloy 800 for its 100,000-hour rupture strength above 600 °C. The figures below are published typical values for solution-annealed material and are given for screening and material selection.
| Temperature | Rupture stress, MPa | Rupture stress, ksi |
|---|---|---|
| 650 °C / 1200 °F | About 100 | About 14.5 |
| 760 °C / 1400 °F | About 45 | About 6.5 |
| 815 °C / 1500 °F | About 30 | About 4.4 |
| 870 °C / 1600 °F | About 20 | About 2.9 |
These are not design values. For code work, take allowable stresses from ASME Boiler and Pressure Vessel Code Section II Part D, or from the equivalent clause in the governing standard. We forge and certify to the specification issued by the design authority.
Degrees Celsius
Temperature limits
Four temperatures govern the performance of an 800H forging: the point at which the grade becomes worth its cost, the pressure code limit, the finish-forging floor and the annealing temperature.
Service temperature
Alloy 800 range
800H specified, creep governs
Oxidation resistant, above code limit
Hot working and heat treatment
Finish forging above 980 °C
Forge 1150 to 1230 °C
500 °C
700 °C
900 °C
1100 °C
1300 °C
| Threshold | Value | Why it matters |
|---|---|---|
| Grade crossover | About 600 °C / 1100 °F | Below this, Alloy 800 is adequate and cheaper. Above it, creep governs and 800H is specified. |
| ASME VIII-1 limit | 815 °C / 1500 °F | Maximum design temperature for 800H and 800HT in ASME Section VIII Division 1 pressure equipment. |
| Finish-forging floor | About 980 °C / 1800 °F | Finishing below this produces worked grain that can fail the ASTM 5 requirement and shorten rupture life. |
| Solution anneal | 1121 °C / 2050 °F minimum | Required for N08810. We anneal at 1150 to 1175 °C and cool rapidly to set the coarse grain structure. |
Cross-reference
Standards and designations
Alloy 800H forgings are supplied to ASTM B564 and ASME SB-564. Bar is covered by ASTM B408, plate and sheet by ASTM B409, seamless pipe and tube by ASTM B407, and fittings by ASTM B366. The alloy is approved in ASME Section VIII Division 1 for design temperatures up to 815 °C (1500 °F), and in ASME Code Case N-201 for Class 1 nuclear components.
| System | Designation |
|---|---|
| UNS | N08810 (800H), N08811 (800HT), N08800 (800) |
| Werkstoff, DIN 17460 | 1.4958, X5NiCrAlTi31-20 |
| Trade names | Incoloy 800H, Nicrofer 3220 H, Alloy 800H |
| Forgings | ASTM B564 / ASME SB-564 |
| Bar and rod | ASTM B408 / ASME SB-408 |
| Plate, sheet, strip | ASTM B409 / ASME SB-409 |
| Seamless pipe and tube | ASTM B407 / ASME SB-407 |
| Fittings | ASTM B366 |
| Pressure equipment approval | ASME BPVC Section VIII Div. 1 to 815 °C, ASME Code Case N-201 |
| Ultrasonic testing | EN 10228-3, SEP 1921, ASTM A388 |
| Certification | EN 10204 type 3.1 works, or type 3.2 third party through TÜV, BV, LRS, DNV or SGS |
Confirm the edition and any applicable code case against your project specification before release. Where a client specification is stricter than the ASTM minimum, for example a tighter Al plus Ti range, restricted trace elements or additional hot tensile testing, we quote to the client specification.
Open-die and ring rolled
Alloy 800H forged products and size range
We forge Alloy 800H into seamless rolled rings, discs, shafts, flanges, hollow bars, tube sheets, sleeves, bushings, valve bodies and near-net blanks, in single-piece weights from about 20 kg to 15 tonnes. All work is made to drawing. There is no catalogue and no tooling charge on open-die work.
Discs and blanks
Upset-forged discs for tube sheets, blind flanges, closure plates and machined covers.
OD up to 2,000 mm, thickness up to 600 mmShafts and stepped bars
Open-die drawn shafts, spindles and stems with axial grain flow along the length.
Diameter 80-800 mm, length up to 6,000 mmFlanges
Weld-neck, slip-on, blind and drawing-specific flanges to ASME B16.5 or B16.47.
Half inch to 60 inch, Class 150 to 2500Hollow bars and sleeves
Trepanned or mandrel-forged hollows for bushings, sleeves and valve seat rings, with less machining and less scrap.
OD 120-900 mm, bore from 60 mmBlocks and near-net shapes
Rectangular and profiled blocks for valve bodies, manifolds and machined weldments.
Single-piece weight 20 kg to 15 tSizes outside this range can often still be produced. Forging reduction ratio is normally 4:1 or better, and where a client specification states a minimum ratio we record it on the certificate.
Production route
How an Alloy 800H forging is made
The sequence below is the route every Alloy 800H forging follows through the shop.
- MeltingElectric arc furnace with VOD refining, followed by electroslag remelting where the specification or the section size requires it.
- Billet verificationChemistry confirmed by optical emission spectrometry, with positive material identification and heat number transfer before cutting.
- HeatingCharged into a controlled gas or electric furnace and soaked at 1150 to 1230 °C against a recorded thermocouple chart.
- ForgingOpen-die drawing, upsetting and piercing, or radial-axial ring rolling. Finish temperature is held above 980 °C to protect the coarse grain structure.
- Solution annealingReheated to 1150 to 1175 °C, held, then cooled rapidly. This step sets the ASTM 5 grain size and the creep strength.
- Rough machiningScale removed and surfaces prepared so that ultrasonic examination gives a valid result.
- Non-destructive testingUltrasonic to EN 10228-3, SEP 1921 or ASTM A388. Liquid penetrant to ASTM E165 where required.
- Mechanical testingTensile to ASTM E8/E8M, hardness, grain size to ASTM E112, and ASTM A262 Practice E intergranular corrosion testing on request.
- Dimensional inspection and markingChecked against drawing, then hard stamped with heat number, specification, grade and our identification.
- Certification and packingEN 10204 3.1 works certificate, or 3.2 countersigned by TÜV, BV, LRS, DNV or SGS. Seaworthy packing with export documents.
Service
Applications for Alloy 800H forgings
Alloy 800H forgings are used where components carry load in air, steam or carburising gas above 600 °C for extended periods. Typical plant includes steam methane reformers, ethylene cracking furnaces, heat treatment equipment and the pressure equipment around them.
Petrochemical and refining
- Steam methane reformer outlet manifolds, pigtails and transfer line components
- Ethylene pyrolysis furnace headers and return bends
- Hydrogen and ammonia plant high-temperature piping components
- Superheater and reheater fittings
Pressure equipment and heat transfer
- Tube sheets and channel covers for shell and tube heat exchangers
- Forged flanges, nozzles and shell courses for pressure vessels and air receivers
- Columns, towers, silos and preheater components
Heat treatment and furnace plant
- Retorts, muffles, radiant tube supports and furnace fixtures
- Carburising and nitriding baskets and grids
- Rolls and rotating parts for continuous heat treatment lines
Valves and flow control
- Valve bodies, bonnets, stems and forged valve seat rings
- Gate, globe, ball, check and plug valve components for high-temperature service
- Strainer bodies and manifold blocks
Power, energy and nuclear
- Gas turbine and compressor casings and rings
- High-temperature gas-cooled reactor components under ASME Code Case N-201
- Waste-to-energy and biomass boiler hardware
Process and heavy industry
- Chemical pump and plunger pump shafts, sleeves and bushings
- Offshore, subsea, wellhead and christmas tree components
- Cement, sugar, paper and pulp, and pharmaceutical process equipment
- Forged wheels, rolls, gears and crankshafts for heavy machinery
Fabrication
Welding and machining Alloy 800H
Welding
Alloy 800H is welded by GTAW, GMAW, SMAW and SAW. For components that carry load at temperature, match the creep strength of the base metal. ERNiCr-3 (Filler Metal 82) and ENiCrFe-2 or ENiCrFe-3 are common choices, and ERNiCrCoMo-1 (Alloy 617 filler) is used where the highest rupture strength is needed. Keep heat input and interpass temperature low and clean the joint between passes. Post-weld heat treatment is normally not required, and an unnecessary PWHT can alter the grain structure.
Machining
The alloy work hardens. Use a rigid setup, sharp positive-rake carbide tooling, low cutting speed with heavy positive feed, no dwelling in the cut, and flood coolant. Where the finished part carries a large machining allowance, we can rough machine before final annealing to shorten your cycle time.
Corrosion behaviour
The nickel content gives good resistance to chloride stress-corrosion cracking, and chromium with aluminium gives resistance to oxidation, carburisation and nitriding in high-temperature process gas. Alloy 800H is a high-temperature alloy. For aggressive wet chloride pitting service, Alloy 825 or Alloy 625 is the better choice.
Enquiry
How to order Alloy 800H forgings
Send a drawing or the finished dimensions to sales@steelforgepieces.com and we will quote within 24 working hours. There is no minimum order value on open-die work, and we quote single prototype pieces as well as production batches.
What to include in the enquiry
- Grade and specification, for example Alloy 800H to ASTM B564, or dual 800H/800HT
- Drawing or finished dimensions, and whether you want as-forged, rough-machined or finish-machined
- Quantity and required delivery date
- Certificate type, EN 10204 3.1 or 3.2 with your preferred third party
- NDT scope and acceptance class, for example EN 10228-3 class, SEP 1921 group or ASTM A388 criteria
- Any client or project specification that overrides the standard
| Item | Detail |
|---|---|
| Minimum order | One piece, no MOQ on open-die forgings |
| Quotation time | Within 24 working hours of receiving the drawing |
| Lead time | Normally 25 to 45 days from order confirmation, depending on section size and NDT scope |
| Condition supplied | Solution annealed, as-forged, rough-machined or finish-machined |
| Documentation | EN 10204 3.1 or 3.2, NDT reports, dimensional report, heat treatment charts |
| Terms and shipping | EXW, FOB, CIF or DDP from Shanghai or Ningbo |
Common questions
Frequently asked questions
What is the difference between Alloy 800H and Alloy 800?
Alloy 800H is a controlled version of Alloy 800 with carbon restricted to 0.05 to 0.10 %, combined aluminium plus titanium of 0.30 to 1.20 %, a grain size of ASTM 5 or coarser, and a solution anneal above 1121 °C. These controls raise creep and stress-rupture strength above 600 °C. Below 600 °C the two grades perform much the same, and standard Alloy 800 is the cheaper option.
What is the maximum service temperature of Alloy 800H?
For pressure equipment built to ASME Section VIII Division 1, the maximum design temperature is 815 °C (1500 °F). The alloy keeps useful oxidation resistance up to roughly 1100 °C in non-pressure applications such as furnace fixtures and retorts, although strength rather than oxidation becomes the limiting factor at that level.
Which specification covers Alloy 800H forgings?
ASTM B564, or ASME SB-564, is the specification for nickel alloy forgings and covers UNS N08810. Related product forms are ASTM B408 for bar, B409 for plate and sheet, B407 for seamless pipe and tube, and B366 for fittings.
Why does Alloy 800H require a grain size of ASTM 5 or coarser?
Creep resistance improves as grain boundary area falls, because grain boundary sliding is a dominant creep mechanism at high temperature. A coarse grain structure therefore gives longer rupture life. It is achieved by finishing the forging above about 980 °C and annealing above 1121 °C. If the finish temperature is too low or the anneal too cold, the part will fail the grain size check even when the chemistry is correct.
Can Alloy 800H be welded, and does it need post-weld heat treatment?
Yes. It welds by GTAW, GMAW, SMAW and SAW, normally with ERNiCr-3 (Filler Metal 82), ENiCrFe-2 or ENiCrFe-3, or ERNiCrCoMo-1 where maximum creep strength is needed. Post-weld heat treatment is normally not required. Keep heat input low and clean each pass thoroughly.
Is Alloy 800H magnetic?
Effectively no. The austenitic structure gives a magnetic permeability of about 1.010 at 200 oersted at room temperature, so it behaves as a non-magnetic material in normal service.
Should I order 800H or dual-certified 800H/800HT?
If the specification names either grade, ask for dual certification to N08810/N08811. It costs nothing extra at the enquiry stage and avoids a re-melt if the project specification changes later. The constraint is that 800HT requires aluminium plus titanium of 0.85 to 1.20 % against 0.30 to 1.20 % for 800H, so the heat has to be aimed at the narrower window from the start.
What size Alloy 800H forgings can you produce?
Jiangyin Jiangnan Metal produces Alloy 800H seamless rolled rings from 200 mm to 3,000 mm outside diameter, discs to 2,000 mm diameter and 600 mm thick, shafts to 800 mm diameter and 6,000 mm long, and single pieces from about 20 kg up to 15 tonnes. Sizes outside this range can often still be produced.
What certificates and testing come with the order?
Every forging ships with an EN 10204 type 3.1 works certificate, or type 3.2 countersigned by TÜV, BV, LRS, DNV or SGS. Standard scope covers chemical analysis, tensile testing to ASTM E8/E8M, hardness, grain size to ASTM E112, and ultrasonic testing to EN 10228-3, SEP 1921 or ASTM A388. Liquid penetrant, hot tensile and ASTM A262 Practice E intergranular corrosion testing are available on request.
Where can I buy Alloy 800H forged rings, discs and flanges?
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No. 1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, producing Alloy 800H forgings to ASTM B564 and exporting worldwide. Email sales@steelforgepieces.com or call +86 189-2135-9659 with a drawing for a quotation within 24 working hours.
What is the lead time for Alloy 800H forgings?
Normally 25 to 45 days from order confirmation. Section size, the annealing cycle and the extent of NDT and third-party witnessing are what move that figure. Rough-machined parts and third-party-witnessed inspection sit at the longer end.
Reference
Jiangyin Jiangnan Metal Co., Ltd. (2026). Alloy 800H Forgings (UNS N08810): Composition, Properties, Standards and Manufacturing. Jiangyin, Jiangsu, China. https://www.steelforgepieces.com/Nickel-Alloy/ALLOY-800H.html
Manufacturer
About Jiangyin Jiangnan Metal Co., Ltd.
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory in Jiangyin, Jiangsu Province, China, producing forged rings, discs, shafts, flanges and blocks in carbon steel, alloy steel, tool steel, stainless steel and nickel alloys including Alloy 800H, Inconel, Incoloy, Hastelloy, Monel and Nimonic grades.
We forge to drawing rather than to catalogue, which means no tooling charge and no minimum order quantity. A single prototype ring for a reformer trial is quoted on the same basis as a repeat production batch. Jiangyin sits in the Yangtze River Delta forging cluster, about two hours from Shanghai port.
The technical data on this page reflects our production practice for UNS N08810, covering melting route, forging window, annealing cycle and inspection scope, together with the requirements of ASTM B564 and the ASME Boiler and Pressure Vessel Code.