Nickel Alloy · NCF 800T · UNS N08811 · W.Nr. 1.4959
NAS 800T Forgings
Seamless rolled rings, flanges, round bars, discs, shafts, sleeves, bushings and tube sheets, open-die forged in NAS 800T to your drawing.
NAS 800T is a high-nickel heat-resisting Fe-Ni-Cr alloy, the Nippon Yakin Kogyo designation for NCF 800T / UNS N08811. It contains 30–35% nickel, 19–23% chromium and a minimum of 39.5% iron. Carbon is held at 0.06–0.10%, aluminium plus titanium are controlled together, and a high-temperature anneal coarsens the grain. These three controls produce the creep-rupture strength of the grade above 593 °C (1100 °F). Below that temperature NAS 800 is normally sufficient and cheaper.
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. It forges NAS 800T to customer drawings as seamless rolled rings to 3,000 mm outside diameter, discs to Ø2,500 mm, bars Ø80–800 mm, shafts to 6,000 mm long and single pieces to 10,000 kg. Material is melted by EAF + VOD + ESR, supplied solution annealed, ultrasonically tested and certified to EN 10204 3.1 or 3.2. For a quotation, email sales@steelforgepieces.com or call +86 189 2135 9659.
Key temperatures for NAS 800T
Temperature decides whether to specify NAS 800, NAS 800H or NAS 800T, and how the forging is heat treated.
NAS 800T at a glance
- Grade
- NAS 800T (also written NAS800T, NAS 800-T)
- JIS designation
- NCF 800T
- UNS number
- N08811
- Werkstoff / DIN
- 1.4959 / X8NiCrAlTi32-21
- Producer of the brand
- Nippon Yakin Kogyo Co., Ltd. (NAS® is their trademark)
- Alloy family
- Nickel-iron-chromium, austenitic, solid solution, non-hardenable
- Forging standards
- JIS G4902 (as called out) · ASTM B564 / ASME SB-564 for forgings
- Melting route
- EAF + VOD, with ESR remelt on request
- Delivery condition
- Solution annealed and rapid cooled, not age hardened
- Typical service range
- 593–982 °C (1100–1800 °F)
- Density
- 7.94 g/cm³ (0.287 lb/in³)
- Melting range
- 1357–1385 °C (2475–2525 °F)
- Certification
- EN 10204 3.1 as standard, 3.2 third-party witnessed on request
- Forged by
- Jiangyin Jiangnan Metal Co., Ltd., Jiangyin, Jiangsu, China
What NAS 800T is, and when to specify it
NAS 800T is the high-temperature member of the 800 alloy family as produced under the NAS brand. NAS 800, NAS 800H and NAS 800T carry the same nickel, chromium and iron content and behave almost identically in corrosion. What separates them is carbon content, combined aluminium plus titanium, and anneal temperature. Those differences decide how the material holds up under sustained load at temperature.
The alloy has an austenitic structure close to that of austenitic stainless steel, so it is worked, welded and heat treated in a similar way. It resists oxidation, carburisation and sulfidation, stays dimensionally stable at temperature, and does not embrittle through sigma-phase formation the way some higher-chromium stainless grades do. Because the base is iron rather than nickel, it costs less per kilogram than nickel-base alternatives such as Inconel 617 or Haynes 230.
Specification rule: use NAS 800 below 593 °C (1100 °F), and NAS 800H or NAS 800T above it. Choose 800T where the design code calls for the higher allowable stresses, or where the part carries load for tens of thousands of hours.
NAS 800T chemistry always falls inside the NAS 800H (UNS N08810) window, but the reverse is not true. A specification written to 800H alone is therefore satisfied by an 800T heat. Dual N08810 / N08811 certification is normal practice, and we supply it on request.
Chemical composition of NAS 800T
Limits below are in weight percent. The two highlighted rows are the composition controls that separate 800T from 800 and 800H; the third control is the anneal temperature, covered further down.
| Element | Min % | Max % | Role in the alloy |
|---|---|---|---|
| Nickel (Ni) | 30.0 | 35.0 | Stabilises the austenitic matrix; resists chloride stress-corrosion cracking |
| Chromium (Cr) | 19.0 | 23.0 | Forms the protective oxide against oxidation, sulfidation and carburisation |
| Iron (Fe) | 39.5 | balance | Base element; keeps the alloy cheaper than nickel-base grades |
| Carbon (C) | 0.06 | 0.10 | Held deliberately high for creep strength. Tighter than 800H (0.05–0.10) |
| Aluminium (Al) | 0.15 | 0.60 | Combines with Ti for high-temperature structural stability |
| Titanium (Ti) | 0.15 | 0.60 | Ties up carbon and nitrogen; contributes to rupture strength |
| Aluminium + Titanium | 0.85 | 1.20 | The defining restriction of the 800T / N08811 grade. 800H allows 0.30–1.20 |
| Manganese (Mn) | — | 1.5 | Deoxidiser; combines with sulfur |
| Silicon (Si) | — | 1.0 | Deoxidiser; assists oxidation resistance |
| Copper (Cu) | — | 0.75 | Residual limit |
| Sulfur (S) | — | 0.015 | Kept low for hot workability and toughness |
| Phosphorus (P) | — | to spec | Residual; limit set by the ordering standard or the drawing |
The Al + Ti window shown is the UNS N08811 requirement. Where your drawing calls out JIS G4902 alone, confirm the Al + Ti limit against the ordering standard at enquiry stage and we will certify to whichever applies.
Mechanical properties of NAS 800T forgings
Specified minimums, annealed condition
These are the values a mill certificate must meet. They are minimums, not typical values.
| Property | NAS / JIS minimum | ASTM B564 (N08811) |
|---|---|---|
| 0.2% proof (yield) strength, min | ≥ 170 N/mm² | 172 MPa (25 ksi) |
| Tensile strength, min | ≥ 450 N/mm² | 448 MPa (65 ksi) |
| Elongation, min | ≥ 30 % | 30 % in 50 mm / 4D |
| Average grain size | coarse, per anneal | ASTM No. 5 or coarser |
The two columns are the same requirement expressed in two systems and rounded differently. Order to one standard and state it on the drawing.
Typical as-delivered values
Solution-annealed NAS 800T forgings normally test well above the specified minimums. The values below are representative of our production and vary with section size and cooling rate.
| Property | Typical (metric) | Typical (imperial) |
|---|---|---|
| Tensile strength | 520–680 MPa | 75–99 ksi |
| 0.2% proof strength | 210–310 MPa | 30–45 ksi |
| Elongation | 40–55 % | 40–55 % |
| Reduction of area | 50–70 % | 50–70 % |
| Hardness | 120–184 HB | ≈ 126–194 HV |
Typical values are for design screening only. The mill test certificate issued with each forging governs acceptance.
Physical properties of NAS 800T
| 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 × 10⁶ psi |
| Specific heat | 460 J/kg·K | 0.11 Btu/lb·°F |
| Thermal conductivity, 20 °C | 11.5 W/m·K | 80 Btu·in/ft²·h·°F |
| Mean expansion, 20–100 °C | 14.4 µm/m·K | 8.0 × 10⁻⁶ in/in·°F |
| Electrical resistivity | 0.989 µΩ·m | 595 Ω·circ mil/ft |
| Magnetic permeability | 1.009 (at 200 Oe) | essentially non-magnetic |
Nominal values for the 800H / 800T (N08810 / N08811) alloy family, offered for design guidance.
Heat treatment of NAS 800T forgings
NAS 800T is a solid-solution alloy. It is not precipitation hardened, so no ageing treatment is applied and none should be specified. Strength at temperature comes from grain size and from the carbon, titanium and aluminium held in solution, not from a precipitate.
| Treatment | Temperature | Cooling | When it is used |
|---|---|---|---|
| Annealing | 980–1100 °C | Rapid cool | General purpose; restores ductility after forging or cold work |
| High-temperature solution anneal | ≥ 1149 °C (2100 °F) | Rapid cool | Where creep-rupture strength governs. Coarsens grain to ASTM No. 5 or larger, which delivers the allowable design stress |
| Stress-relief anneal | 780–870 °C | Air cool | After welding or machining where distortion must be controlled |
Two common specification errors. The first is calling for solution treatment plus ageing. Ageing does nothing to NAS 800T and only adds furnace time. The second is annealing too low, which leaves a fine grain, so the forging fails the ASTM No. 5 grain-size requirement for N08811.
NAS 800 vs NAS 800H vs NAS 800T
These three are routinely confused on drawings and purchase orders. Nickel, chromium, iron content and corrosion behaviour are effectively the same. Three things differ.
| Criterion | NAS 800 | NAS 800H | NAS 800T |
|---|---|---|---|
| UNS number | N08800 | N08810 | N08811 |
| JIS designation | NCF 800 | NCF 800H | NCF 800T |
| Werkstoff Nr. | 1.4876 | 1.4958 | 1.4959 |
| Carbon, % | 0.10 max | 0.05–0.10 | 0.06–0.10 |
| Al + Ti, % | not restricted | 0.30–1.20 | 0.85–1.20 |
| Grain size requirement | none specified | ASTM No. 5 or coarser | ASTM No. 5 or coarser |
| Anneal temperature | ≈ 980 °C | ≥ 1121 °C | ≥ 1149 °C |
| Normal service ceiling | 593 °C / 1100 °F | above 593 °C | above 593 °C |
| Governing property | room-temperature strength | creep & rupture | creep & rupture, highest allowables |
| Choose it when | Service stays below 593 °C and cost matters | Sustained high-temperature service, standard code allowables | Long-term load above 593 °C, or the code requires the higher allowable stress |
NAS 800T equivalent designations
| System | Designation |
|---|---|
| Brand (Japan) | NAS 800T (Nippon Yakin Kogyo Co., Ltd.) |
| JIS (Japan) | NCF 800T |
| UNS (USA) | N08811 |
| ASTM / ASME | B564 / SB-564 (forgings), B408, B409, B407 |
| Werkstoff Nr. (Germany) | 1.4959 |
| DIN / EN name | X8NiCrAlTi32-21 |
| AFNOR (France) | Z8NC32-21 (nearest) |
| BS (UK) | NA15 family (nearest) |
| Common trade names | Incoloy® 800HT, Alloy 800HT, Nicrofer® 3220 HT, Sandvik Sanicro® 31HT, Pyromet® 800HT |
Designations marked "nearest" are close but not identical. Where a code case or design registration is involved, order to the UNS number and confirm equivalence against the mill certificate.
Applicable standards by product form
| Product form | ASTM | ASME | JIS |
|---|---|---|---|
| Forgings (our core product) | B564 | SB-564 | G4902 (as called out) |
| Rod and bar | B408 | SB-408 | G4901 |
| Plate, sheet and strip | B409 | SB-409 | G4902 |
| Seamless pipe and tube | B407, B163 | SB-407, SB-163 | G4903, G4904 |
| Welded pipe and tube | B514, B515 | SB-514, SB-515 | — |
For pressure-retaining design, the 800H / 800T chemistry carries maximum allowable stresses in the ASME Boiler and Pressure Vessel Code, Section VIII Division 1 up to 816 °C (1500 °F), and is addressed to 982 °C (1800 °F) under Code Case 1983. Nuclear service is covered by Section III Code Cases N-201, N-253 and N-254.
NAS 800T forgings we produce
Every item below is forged to the customer's drawing or dimensional sketch. There is no fixed catalogue, no tooling charge and no minimum order quantity by piece. That is the economic advantage of open-die work.
- Seamless rolled ringsRing-rolled, no weld seam. Rectangular or profiled section.
- Forged flangesWN, SO, blind, long weld neck and orifice, to ASME B16.5 / B16.47 or drawing.
- Round bars & billetsForged and peeled or rough turned; cut to length.
- Discs and blanksUpset forged discs for tube sheets, covers and blind ends.
- Shafts and spindlesStraight, stepped and eccentric shafts; forged crankshafts.
- Sleeves and bushingsHollow forged, trepanned or bored, thin or heavy wall.
- Tube sheetsForged and drilled tube sheets for shell-and-tube exchangers.
- Hollow bars & forged pipeTrepanned or expanded hollows for heavy-wall pipe sections.
- Valve componentsBodies, bonnets, seat rings, stems, gate and plug blanks.
- Nozzles and manifoldsForged nozzle bodies, headers, blocks and custom shapes.
Size and weight capability
| Product form | Dimensional range | Unit weight |
|---|---|---|
| Seamless rolled rings | OD 200–3,000 mm, height to 800 mm | 20–8,000 kg |
| Round bars | Ø80–800 mm, length to 6,000 mm | 20–6,000 kg |
| Discs, tube sheets | Ø200–2,500 mm, thickness to 600 mm | 30–10,000 kg |
| Shafts, sleeves, blocks | to 6,000 mm long | to 10,000 kg |
Machining allowance is normally 6–20 mm per surface depending on section size, unless your drawing states otherwise. Finish-machined parts to print are also supplied.
How we make NAS 800T forgings
- MeltingNAS 800T stock is melted by EAF + VOD, with ESR remelting available where the specification or the service calls for improved cleanliness and reduced segregation.
- Heat verificationHeat chemistry is checked by spectrometer against the ordering standard, including the Al + Ti window that defines the grade, before any material is heated.
- Open-die forgingForged on hammers from 1 to 9 tonnes and hydraulic presses to 5,000 tonnes, with a controlled reduction ratio that closes porosity and develops a wrought grain flow following the part contour. Rings are rolled seamless on mills to 6 m.
- Solution annealingHeld at 1149 °C (2100 °F) minimum where creep strength governs, then rapidly cooled to produce the ASTM No. 5 or coarser grain size. No ageing treatment is applied.
- Rough or finish machiningTurned, bored, drilled and faced to your drawing, with agreed machining allowance or to final dimensions.
- Non-destructive testingUltrasonic examination to EN 10228-3, SEP 1921, ASTM A388 or your nominated class. PT and dimensional inspection as required.
- Certification and despatchEN 10204 3.1 mill certificate as standard; 3.2 with third-party witness (TÜV, BV, LR, SGS, DNV) on request. Marked, preserved and packed for sea or air freight.
Where NAS 800T forgings are used
| Industry | Components forged in NAS 800T |
|---|---|
| Petrochemical & refining | Ethylene cracking furnace headers and outlet fittings, hydrogen reformer pigtail connections, transfer line exchanger parts, forged nozzles and flanges |
| Industrial furnaces & heat treating | Radiant tube components, retort and muffle end rings, fixtures, baskets and roller ends |
| Power generation | Superheater and reheater header forgings, steam-side flanges, tube sheets, high-temperature steam valve bodies |
| Pressure vessels & heat exchangers | Forged tube sheets, shell flanges, blind covers, girth rings, air receivers, shell-and-tube exchanger forgings |
| Chemical processing | Nitric and sulfuric acid plant hardware, ammonia and urea plant exchanger forgings, catalyst grid supports, columns, towers, silos and preheater parts |
| Pumps & rotating equipment | Chemical pump and plunger pump shafts, spindles, sleeves, bushings, gears and gearbox components |
| Valves | Ball, check, globe, gate and plug valve bodies, bonnets, stems, seat rings and blocks |
| Oil & gas, offshore | Subsea and deepwater production system parts, wellhead and christmas tree components, compressor and generator forgings |
| Nuclear | Steam generator tube sheet forgings and heat exchanger components under Section III Code Cases N-201, N-253 and N-254 |
NAS 800T is chosen for these duties because it resists oxidation, carburisation and sulfidation at temperature, holds its dimensions, and costs less per kilogram than a nickel-base alternative.
Testing, inspection and certification
- Chemical analysis. Spectrometric heat analysis and, on request, product analysis on the finished forging.
- Mechanical testing. Room-temperature tensile and elongation; elevated-temperature tensile, stress-rupture and impact testing to your specification.
- Grain size. Determined per ASTM E112. ASTM No. 5 or coarser is mandatory for N08811.
- Ultrasonic testing. EN 10228-3, SEP 1921 Class C/D/E, ASTM A388 or your nominated customer class.
- Surface NDT. Liquid penetrant examination per ASTM E165 / ASME V Article 6; magnetic particle where applicable.
- Intergranular corrosion. ASTM A262 practice as agreed.
- Certification. EN 10204 3.1 as standard; EN 10204 3.2 witnessed by TÜV, BV, LR, SGS or DNV on request. Full heat traceability and hard stamping.
In-house inspection equipment includes universal testing machines, impact testing machines, hardness testers, a metallographic microscope and magnetic particle flaw detectors.
Frequently asked questions about NAS 800T
What is NAS 800T?
NAS 800T is a high-nickel heat-resisting alloy in the Fe-Ni-Cr 800 family, designated NCF 800T in JIS and UNS N08811 internationally. It contains 30–35% nickel, 19–23% chromium and a minimum of 39.5% iron, with carbon at 0.06–0.10% and combined aluminium plus titanium at 0.85–1.20%. NAS is the trademark of Nippon Yakin Kogyo Co., Ltd. The alloy keeps its strength, oxidation resistance and structural stability at high temperature, and is used mainly above 593 °C (1100 °F).
Is NAS 800T the same as Incoloy 800HT or Alloy 800HT?
They are the same material specification, UNS N08811, sold under different brand names. NAS 800T is Nippon Yakin Kogyo's designation; Incoloy® 800HT is Special Metals Corporation's. When ordering from any supplier, specify UNS N08811 together with the product standard (ASTM B564 for forgings) so the requirement is unambiguous, and the brand name becomes irrelevant.
What is the difference between NAS 800, NAS 800H and NAS 800T?
They share the same nickel, chromium and iron content and corrode almost identically. They differ in three things: carbon content, combined aluminium plus titanium, and anneal temperature. NAS 800 (N08800) allows up to 0.10% carbon with no Al + Ti restriction and is used below 593 °C. NAS 800H (N08810) sets carbon at 0.05–0.10% and Al + Ti at 0.30–1.20%. NAS 800T (N08811) tightens these to 0.06–0.10% carbon and 0.85–1.20% Al + Ti and requires a higher solution anneal, which gives the highest creep-rupture strength and allowable design stress of the three.
What is the maximum service temperature of NAS 800T?
For pressure-retaining parts, ASME Boiler and Pressure Vessel Code Section VIII Division 1 assigns maximum allowable stresses up to 816 °C (1500 °F), and Code Case 1983 extends this to 982 °C (1800 °F). For non-pressure parts such as furnace fixtures, the practical limit is set by oxidation and by the applied load, and continuous service around 1000 °C is common. Below 593 °C (1100 °F) the grade is not the economic choice, and NAS 800 should be specified instead.
Which heat treatment is correct for NAS 800T forgings?
Solution annealing followed by rapid cooling. The published general annealing range is 980–1100 °C; where creep-rupture strength governs the design, anneal at 1149 °C (2100 °F) minimum so the grain coarsens to ASTM No. 5 or larger. A stress-relief anneal at 780–870 °C with air cooling may follow welding or heavy machining. NAS 800T is a solid-solution alloy and is not precipitation hardened, so no ageing treatment should be specified.
Can NAS 800T be welded?
Yes. It welds readily by GTAW, GMAW and SMAW, much like an austenitic stainless steel. For high-temperature service, filler metals based on Inconel 617 or Inconel 82 are commonly specified, because a matching 800T filler does not develop the same rupture strength across the weld. Post-weld heat treatment is not normally required for the alloy itself, though the design code may call for it.
What sizes of NAS 800T forgings can you supply?
Seamless rolled rings from 200 to 3,000 mm outside diameter, round bars Ø80–800 mm up to 6,000 mm long, discs and tube sheets to Ø2,500 mm and 600 mm thick, and shafts, sleeves and blocks to 6,000 mm long, with single-piece weights up to 10,000 kg. Because open-die forging needs no dies, one-off and prototype quantities are economic: there is no tooling charge and no minimum order quantity by piece.
Do you supply a material certificate for NAS 800T?
Yes. Every NAS 800T forging ships with an EN 10204 3.1 mill test certificate as standard, showing heat number, chemical analysis, mechanical results, grain size, heat treatment record and NDT results. EN 10204 3.2 certification witnessed by a third party such as TÜV, BV, LR, SGS or DNV is available on request at the time of order.
How long does a NAS 800T forging take to produce?
Lead time depends on whether the grade is in raw stock and on the size of the forging. Simple rings and discs from stock material typically run 25–40 days. Parts needing a new melt, ESR remelting, heavy machining or third-party witnessed inspection take longer. Send the drawing and we will confirm a firm date with the quotation.
Who supplies open-die forged NAS 800T parts in China?
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory located at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. It forges NAS 800T and other nickel alloys, stainless steels, tool steels, alloy steels and carbon steels into seamless rolled rings, flanges, bars, discs, shafts, sleeves, bushings and tube sheets, and exports worldwide. Enquiries: sales@steelforgepieces.com or +86 189 2135 9659.
Request a quotation for NAS 800T forgings
Send a drawing, a sketch, or just the dimensions and quantity. We quote open-die forgings in NAS 800T with no tooling charge and no piece minimum.
Useful details if you have them: grade and standard (NAS 800T / NCF 800T / UNS N08811), product form, dimensions with machining allowance, quantity, delivery condition, NDT class, certificate type (EN 10204 3.1 or 3.2) and required delivery date.
- Company
- Jiangyin Jiangnan Metal Co., Ltd.
- Business
- Open-die forging factory
- Address
- No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
- Telephone / WhatsApp
- +86 189 2135 9659
- sales@steelforgepieces.com
- Website
- www.steelforgepieces.com
Jiangyin Jiangnan Metal Co., Ltd. (2026). "NAS 800T Forgings (NCF 800T / UNS N08811): composition, properties, heat treatment and available forged forms." Jiangyin, Jiangsu, China. https://www.steelforgepieces.com/Nickel-Alloy/NAS800T.html
Related nickel alloy grades we forge
Same 800 family
- Alloy 800HT forgings
- Incoloy 800HT forgings
- Incoloy 800H forgings
- Incoloy 800 forgings
- Incoloy 825 forgings