Jiangyin Jiangnan Metal Co., Ltd.
Seamless rolled rings
Radial-axial rolled, continuous circumferential grain flow, no weld seam.
OD 200-4000 mm, height up to 1000 mmWhat is Incoloy 800?
Incoloy 800 is a wrought nickel-iron-chromium alloy. It was developed for service where an austenitic stainless steel does not have enough nickel to resist chloride stress-corrosion cracking, and where a full nickel-base alloy would cost more than the job needs. The composition sits between the two: about a third nickel, about a fifth chromium, balance mostly iron.
Three things govern how the alloy behaves.
- The austenitic structure is stable. It does not transform on cooling, so the alloy stays tough and practically non-magnetic from cryogenic temperature up to its service limit.
- Chromium at 19 to 23 percent, backed by 0.15 to 0.60 percent aluminium, forms a tight adherent oxide film that holds up against oxidation and carburisation in hot gas.
- Nickel at 30 to 35 percent carries the chloride resistance. This is the main advantage over 304 and 316 stainless, which crack in water that alloy 800 handles without trouble.
Strength at very high temperature is the weak point. Plain alloy 800 has no strong precipitation-hardening mechanism, so above roughly 600 C most designers move to Incoloy 800H or Incoloy 800HT. Those are the same alloy with controlled carbon, coarser grain and controlled aluminium plus titanium for creep strength.
Why buyers specify forgings instead of plate or bar
Open-die forging closes solidification porosity and orients the grain flow along the part axis. Transverse ductility and fatigue life come out higher than on a part machined from rolled bar or cut from plate. On rings, radial-axial ring rolling gives a seamless product with continuous circumferential grain flow, so there is no weld seam to inspect, qualify or fail in service.
Incoloy 800 chemical composition
Composition limits for UNS N08800 are common to ASTM B564 (forgings), ASTM B408 (rod and bar), ASTM B409 (plate, sheet and strip) and ASTM B407 (seamless pipe and tube).
| Element | Minimum | Maximum | Role in the alloy |
|---|---|---|---|
| Nickel (Ni) | 30.0 | 35.0 | Stabilises austenite, carries chloride SCC resistance |
| Chromium (Cr) | 19.0 | 23.0 | Forms the protective Cr2O3 scale, oxidation resistance |
| Iron (Fe) | 39.5 | balance | Base element, keeps cost below nickel-base alloys |
| Carbon (C) | - | 0.10 | Held low to limit grain-boundary carbide precipitation |
| Aluminium (Al) | 0.15 | 0.60 | Improves scale adherence under cyclic oxidation |
| Titanium (Ti) | 0.15 | 0.60 | Ties up carbon, limits sensitisation |
| Manganese (Mn) | - | 1.50 | Deoxidiser, sulfur control |
| Silicon (Si) | - | 1.00 | Deoxidiser, assists oxidation resistance |
| Copper (Cu) | - | 0.75 | Residual limit |
| Sulfur (S) | - | 0.015 | Held low for hot workability |
| Composition limits for UNS N08800 per ASTM B564, B408 and B409. Heat-specific values are reported on the EN 10204 certificate issued with each order. | |||
Mechanical properties of Incoloy 800 forgings
The values below are for the solution-annealed condition at room temperature. The first column is the specified minimum that an acceptance test must meet. The second is what our forgings normally report on the mill certificate.
| Property | Specified minimum | Typical as forged and annealed |
|---|---|---|
| Tensile strength | 515 MPa (75 ksi) | 550-620 MPa |
| Yield strength, 0.2% offset | 205 MPa (30 ksi) | 240-310 MPa |
| Elongation in 4D | 30% | 38-48% |
| Reduction of area | - | 55-70% |
| Hardness | - | 120-184 HB |
| Charpy V impact energy at 20 C | by agreement | above 150 J |
Strength at temperature
Yield strength falls off gradually as temperature rises. Above about 600 C it is creep behaviour, not short-term tensile strength, that sets the practical limit.
| Temperature | Tensile strength | 0.2% yield strength |
|---|---|---|
| 20 C | about 590 MPa | about 285 MPa |
| 300 C | about 520 MPa | about 205 MPa |
| 540 C | about 480 MPa | about 180 MPa |
| 650 C | about 390 MPa | about 165 MPa |
| 760 C | about 235 MPa | about 150 MPa |
| Typical values for orientation only. Do not use them for design. Take allowable stresses from ASME BPVC Section II Part D or the governing design code. | ||
For continuous service above about 600 C, specify alloy 800H or 800HT instead. Their code allowable stresses in the creep range are considerably higher, and the difference in raw material cost is small next to the cost of a re-order.
Physical properties
| Property | Value | Condition |
|---|---|---|
| Density | 7.94 g/cm3 (0.287 lb/in3) | 20 C |
| Melting range | 1357-1385 C (2475-2525 F) | - |
| Modulus of elasticity | 196 GPa (28.5 x 10^3 ksi) | 20 C, tension |
| Specific heat | 460 J/kg K | 20 C |
| Thermal conductivity | 11.5 W/m K | 20 C |
| Mean thermal expansion | 14.4 um/m K | 20 to 100 C |
| Electrical resistivity | 0.99 uohm m | 20 C |
| Relative magnetic permeability | about 1.01 | 20 C, practically non-magnetic |
| Curie temperature | about -115 C | - |
That permeability figure has a practical consequence on the shop floor. Magnetic particle inspection does not work on this alloy. Surface examination of Incoloy 800 forgings is done by liquid penetrant testing to ASTM E165. Any specification calling for MT on alloy 800 should be queried before the order is placed.
Incoloy 800 compared with 800H, 800HT, 825 and Inconel 600
These five grades come up together in most enquiries. The differences that change a purchase decision are carbon level, grain size, aluminium plus titanium content, and where each alloy performs best.
| Grade | UNS | Ni % | Cr % | Distinguishing requirement | Where it performs best |
|---|---|---|---|---|---|
| Incoloy 800 | N08800 | 30-35 | 19-23 | C max 0.10%, annealed at 980 C or above | General oxidation and chloride SCC resistance up to about 600 C |
| Incoloy 800H | N08810 | 30-35 | 19-23 | C 0.05-0.10%, ASTM grain size 5 or coarser, annealed at 1093 C or above | Creep and rupture strength between 600 and 900 C |
| Incoloy 800HT | N08811 | 30-35 | 19-23 | 800H requirements plus Al + Ti of 0.85-1.20% | Long-term creep life, reformer and furnace header service |
| Incoloy 825 | N08825 | 38-46 | 19.5-23.5 | Adds 2.5-3.5% Mo and 1.5-3.0% Cu | Wet corrosion, sulfuric and phosphoric acid, sour service |
| Inconel 600 | N06600 | 72 min | 14-17 | Nickel-base rather than iron-base | Caustic service and chloride ion SCC where cost is secondary |
Short version for buyers: alloy 800 for heat and chloride resistance below 600 C, 800H or 800HT when the design code needs creep allowables above 600 C, 825 when the problem is acid rather than heat.
How we forge Incoloy 800
Incoloy 800 has a narrower usable hot-working window than carbon or low-alloy steel and it work-hardens quickly. Temperature control during forging is therefore the main quality variable. The route below is what runs on our shop floor in Jiangyin.
Incoloy 800 hot-working window
Scale runs 850 C to 1250 C. The bracketed band is the usable forging range.
- Soak 1150-1205 C
- Heavy reduction 1205-1050 C
- Finish below 980 C
- Anneal 980 C or above
Route, stage by stage
- Melting. Incoloy 800 stock is melted by EAF with AOD or VOD refining. Electroslag remelting is added when the customer requires better cleanliness, tighter segregation control or a pressure-vessel pedigree.
- Heating. Billets are soaked at 1150 to 1205 C with recorded furnace charts. Above roughly 1230 C the grain boundaries begin to melt locally and the billet is scrap, so soak temperature is controlled and logged rather than judged by eye.
- Open-die forging. Drawing and upsetting between 1205 C and about 1050 C, with reheats as needed. We work to a total forging ratio of 3:1 or higher unless the drawing says otherwise, which closes centreline porosity and lines the grain flow up with the loaded axis.
- Finishing reduction and ring rolling. The last reduction is taken below about 980 C to refine grain size. Ring blanks are upset, pierced and expanded on a radial-axial ring rolling mill, which gives seamless rolled rings with continuous circumferential grain flow.
- Solution annealing. Covered in the next section.
- Machining, testing and certification. Rough or finish machining to drawing, then the test scope agreed at order.
Heat treatment of Incoloy 800 forgings
Alloy 800 is supplied solution annealed. The point of the cycle is to dissolve chromium carbides back into solution and then get the part past the precipitation range fast enough that they do not re-form on the grain boundaries.
| Grade | Annealing temperature | Cooling | Resulting grain size |
|---|---|---|---|
| Alloy 800 | 980 C (1800 F) or above | Water quench or rapid air cool | Fine, ASTM 5 or finer typical |
| Alloy 800H | 1093 C (2000 F) or above | Air cool | ASTM 5 or coarser, required |
| Alloy 800HT | 1149 C (2100 F) or above | Air cool | ASTM 5 or coarser, required |
The critical range is 760 to 540 C. Chromium carbides precipitate at the grain boundaries while the part sits in that window, and each carbide leaves a chromium-depleted zone beside it. That is the mechanism behind intergranular attack in wet service. Section thickness matters here: a 300 mm thick tube sheet cannot be cooled at its centre as fast as a 40 mm ring. Where the service is wet and corrosive we settle quench method and section size with the customer before the order is confirmed.
Alloy 800 is not precipitation hardenable in the way Inconel 718 and Incoloy 925 are. Requests for a solution plus age cycle on alloy 800 usually trace back to a specification written for a different grade, and are worth checking before production starts.
Incoloy 800 forgings we produce, and sizes
Everything is made to customer drawing or dimension sheet, in as-forged, rough-machined or finish-machined condition.
Forged flanges
Weld neck, slip on, blind, long weld neck and special bore, to ASME B16.5, B16.47 or drawing.
DN 15 to DN 2000, Class 150 to 2500Shafts and spindles
Stepped shafts, spindles, eccentric shafts and pump shafts with grain flow along the axis.
Dia 80-1200 mm, length up to 8000 mmDiscs and tube sheets
Solid discs, blanks and drilled tube sheets for shell-and-tube heat exchangers.
Dia up to 2500 mm, thickness up to 600 mmSleeves, bushings, hollow bars
Bored and trepanned hollows, sleeves and bushings, with less machining waste than solid bar.
OD 100-1500 mm, length up to 4000 mmBlocks, bars and valve parts
Round, square and rectangular blocks, valve bodies, seat rings, stems and nozzles.
Piece weight 5-20,000 kg| Item | What we supply |
|---|---|
| Delivery condition | Solution annealed. As-forged, rough machined or finish machined to drawing |
| Surface | Descaled, pickled or machined all over as specified |
| Standards | ASTM B564 and ASME SB-564, ASTM B408 bar, EN 10095, EN 10028-7, VdTUV 412 on request |
| Certification | EN 10204 3.1 as standard, 3.2 with TUV, BV, SGS, Lloyd's or customer inspector |
| Minimum order | One piece. Prototypes and single spares accepted |
| Typical lead time | 25 to 45 days from drawing approval, depending on size and test scope |
| Delivery terms | EXW Jiangyin, FOB Shanghai or Ningbo, CIF or DDP by agreement |
Where Incoloy 800 forgings are used
Petrochemical and refining
Steam-methane reformer and ethylene furnace components, pigtails and header connections, transfer-line exchanger parts, forged nozzles and flanges on process vessels running hot hydrocarbon and hydrogen streams.
Heat exchangers and pressure vessels
Tube sheets, channel covers, girth and nozzle rings, blind and weld-neck flanges, shell forgings for shell-and-tube exchangers, air receivers, columns and towers. The alloy earns its place wherever cooling water carries chlorides that would crack 304 or 316.
Power generation and nuclear
Steam generator components, superheater and reheater header forgings, feedwater heater tube sheets, support hardware in high-temperature steam circuits.
Heat treatment and furnace equipment
Retorts, muffles, radiant tube components, fixtures, roller and fan shafts, carburising furnace hardware. In this service the carburisation resistance of the alloy sets the replacement interval directly.
Chemical process, valves and rotating equipment
Nitric acid and other oxidising service parts, valve bodies, seat rings, gate and ball valve stems and blocks. Also pump shafts, sleeves, impeller hubs and gear blanks for chemical and plunger pumps, compressors and gearboxes.
Offshore, marine and heavy machinery
Subsea and deepwater production hardware, wellhead and christmas tree components, industrial air compressor and nitrogen generator parts, forged rolls, wheels and manifolds for shipbuilding, cement, sugar, pulp and paper mills.
Welding and machining Incoloy 800
Welding
Alloy 800 welds by GTAW, GMAW and SMAW. Typical consumables are ERNiCr-3 bare wire and ENiCrFe-2 or ENiCrFe-3 covered electrodes. Post-weld heat treatment is not normally required for alloy 800 unless the service environment or the governing code calls for it. Keep interpass temperature low, keep heat input moderate, and clean the joint thoroughly. Sulfur and lead from marking crayons, grease or cutting fluid cause hot cracking in nickel alloys.
Machining
The alloy work-hardens rapidly. Machining behaviour feels broadly like 302, 303, 410, 420, 430 and 430F stainless, but with higher strength and a stronger tendency to harden under a rubbing tool.
- Rigid setup, minimum overhang, sharp tools with positive rake.
- Slower speeds with heavy constant feed. A light feed rubs, and rubbing hardens the surface faster than the tool can cut it.
- Never let the tool dwell in the cut. Take a positive depth of cut under any previously work-hardened layer.
- Generous, well-directed coolant.
For that reason, ordering a forging that is rough machined close to net shape often works out cheaper for the buyer than taking an oversized block and removing the metal in house.
Testing, inspection and certification
| Test | Standard | Scope |
|---|---|---|
| Chemical analysis | Spectrometric, per heat | Standard |
| Tensile test | ASTM A370 or ISO 6892-1 | Standard |
| Hardness | ASTM E10, Brinell | Standard |
| Grain size | ASTM E112 | Standard on 800H and 800HT |
| Ultrasonic testing | EN 10228-3, SEP 1921, ASTM A388 | Standard on pressure parts |
| Liquid penetrant testing | ASTM E165 | On request, replaces MT as the alloy is non-magnetic |
| Positive material identification | XRF or OES | On request |
| Intergranular corrosion | ASTM A262 or ASTM G28 | On request for wet corrosive service |
| Impact test | ASTM A370 Charpy V | On request, including sub-zero |
| Certificate | EN 10204 3.1 or 3.2 | 3.1 standard, 3.2 with third-party inspector |
Each forging is traceable to its heat number. The number is hard-stamped or vibro-etched on the part and printed on the certificate together with the furnace charts for the solution anneal.
What to send with an Incoloy 800 enquiry
A quotation for a forging needs eight pieces of information. With these we normally return a firm price and lead time within one working day.
- Grade and standard. Incoloy 800, 800H or 800HT, and the standard it must meet, for example ASTM B564.
- Drawing or rough dimensions. A PDF, STEP or DWG file, or simply OD by ID by height for a ring.
- Machining condition. As-forged, rough machined with allowance, or finish machined.
- Quantity, and whether the part repeats. A one-off spare and an annual call-off are priced differently.
- Test and certification scope. UT class, PT, impact, IGC, EN 10204 3.1 or 3.2.
- Service conditions. Design temperature, pressure and medium, so we can flag it if 800H or 825 would serve you better.
- Delivery term and port. EXW, FOB Shanghai or Ningbo, CIF or DDP.
- Required delivery date.
Send it to sales@steelforgepieces.com, or WhatsApp and WeChat +86 189 2135 9659. Drawings are treated as confidential and are not shared outside our engineering and production team.
Frequently asked questions about Incoloy 800
What is Incoloy 800?
Incoloy 800, also called alloy 800 and designated UNS N08800, is a nickel-iron-chromium alloy containing 30 to 35 percent nickel, 19 to 23 percent chromium and at least 39.5 percent iron, with small additions of aluminium and titanium. The structure is austenitic and stable, and the alloy resists oxidation, carburisation and chloride stress-corrosion cracking at elevated temperature.
What is the UNS number and material number for Incoloy 800?
The UNS number is N08800. The European material number is 1.4876 and the EN/DIN designation is X10NiCrAlTi32-20. The Japanese equivalent is JIS NCF 800, the British designation is BS NA15 and the French designation is AFNOR Z8NC32-21.
What is the difference between Incoloy 800, 800H and 800HT?
The three grades share the same base composition. Alloy 800 allows carbon up to 0.10 percent and is normally used below about 600 C. Alloy 800H restricts carbon to 0.05 to 0.10 percent, requires ASTM grain size 5 or coarser and a solution anneal above about 1093 C, which raises creep and rupture strength. Alloy 800HT adds a controlled aluminium plus titanium total of 0.85 to 1.20 percent on top of the 800H requirements, giving the most consistent long-term creep strength above 600 C.
Which standard covers Incoloy 800 forgings?
Forgings and forged fittings are normally ordered to ASTM B564, adopted in the ASME Boiler and Pressure Vessel Code as ASME SB-564. Related standards are ASTM B408 for rod and bar, ASTM B409 for plate, sheet and strip, ASTM B407 for seamless pipe and tube and ASTM B366 for wrought fittings.
What is the forging temperature range for Incoloy 800?
Incoloy 800 is heated to 1150 to 1205 C and forged down to about 925 C. Heavy reduction is taken in the upper part of that range and the final reduction below about 980 C to refine grain size. Heating above roughly 1230 C causes incipient melting at the grain boundaries and scraps the billet.
How is Incoloy 800 heat treated after forging?
Alloy 800 forgings are solution annealed at 980 C or above and cooled rapidly. Fast cooling through the 760 to 540 C range limits chromium carbide precipitation at the grain boundaries and protects intergranular corrosion resistance. Alloy 800H and 800HT are annealed higher, at about 1093 C and 1149 C, to develop the coarse grain size their creep strength depends on.
Is Incoloy 800 magnetic?
No. It is practically non-magnetic at room temperature, with a relative magnetic permeability of about 1.01 and a Curie temperature near minus 115 C. Surface crack detection therefore uses liquid penetrant testing to ASTM E165 instead of magnetic particle testing.
Can Incoloy 800 be welded?
Yes. It welds by GTAW, GMAW and SMAW. Common fillers are ERNiCr-3 for gas-shielded processes and ENiCrFe-2 or ENiCrFe-3 covered electrodes for manual welding. Post-weld heat treatment is not normally required for alloy 800 unless the service environment or design code calls for it.
Does Incoloy 800 resist chloride stress corrosion cracking?
Yes. The 30 to 35 percent nickel content gives much better resistance to chloride SCC than austenitic stainless steels such as 304 and 316. This is the main reason it is specified for heat exchanger tube sheets and pressure parts handling chloride-bearing water and process streams.
What is the maximum service temperature of Incoloy 800?
It resists oxidation in air up to roughly 1100 C, but the useful structural limit depends on stress and time. Alloy 800 is generally applied up to about 600 C where creep is not the limiting factor. Above that, alloy 800H or 800HT is specified because their controlled carbon, coarse grain size and aluminium-titanium content give higher creep-rupture strength.
What sizes of Incoloy 800 forgings can you produce?
Jiangyin Jiangnan Metal Co., Ltd. produces Incoloy 800 open-die forgings from about 5 kg to 20,000 kg per piece. That covers seamless rolled rings from 200 mm to 4000 mm outside diameter, shafts up to 8000 mm long, and discs and tube sheets up to 2500 mm diameter. All parts are made to customer drawing in as-forged, rough-machined or finish-machined condition.
How is the price of an Incoloy 800 forging calculated?
Price follows forged weight rather than finished weight, together with the nickel and chromium raw material index at the time of order, machining allowance, testing and certification scope, quantity and delivery term. A drawing or the rough dimensions with the required standard and test scope is enough for a firm quotation.
Standards and references
- ASTM B564 and ASME SB-564, nickel alloy forgings. The primary ordering standard for the products on this page.
- ASTM B408, nickel-iron-chromium alloy rod and bar (UNS N08800, N08810, N08811).
- ASTM B409, nickel-iron-chromium alloy plate, sheet and strip.
- ASTM B407, nickel-iron-chromium alloy seamless pipe and tube.
- ASTM B366, factory-made wrought nickel and nickel alloy fittings.
- ASME BPVC Section II Part D, allowable stresses used for design in pressure equipment.
- EN 10095, EN 10028-7 and DIN 17460, European standards covering X10NiCrAlTi32-20, material number 1.4876.
- EN 10204, types of inspection document, 3.1 and 3.2 certificates.
- EN 10228-3, SEP 1921 and ASTM A388, ultrasonic examination of forgings.
- ASTM E165, liquid penetrant examination.
- ASTM E112, determining average grain size.
- NACE MR0175 and ISO 15156, materials for use in H2S-containing environments.
Incoloy is a registered trademark of Special Metals Corporation. Jiangyin Jiangnan Metal Co., Ltd. is not affiliated with the trademark owner. The designation is used here to identify the alloy grade UNS N08800, as is standard practice in the forging industry.
Request a quotation for Incoloy 800 forgings
Send a drawing or the rough dimensions and we will come back with a firm price, forged weight and lead time, normally within one working day. Single pieces and repeat production are both welcome.
Company
Jiangyin Jiangnan Metal Co., Ltd.
Open-die forging factory
Factory address
No.1 Chengxiqiao Road,Zhouzhuang Town, Jiangyin City,
Jiangsu Province, China
Phone, WhatsApp, WeChat
Page information
Reference for this page: Jiangyin Jiangnan Metal Co., Ltd. Incoloy 800 Forgings (UNS N08800). https://www.steelforgepieces.com/Nickel-Alloy/Incoloy-800.html
Written and reviewed by the engineering and quality team of Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory in Jiangyin, Jiangsu Province, China. Composition and property limits are quoted from the ASTM and EN standards listed above. Capability figures describe our own production. Last reviewed 16 August 2026.
Corrections and technical questions are welcome at sales@steelforgepieces.com.