01 / Grade overviewWhat is 1.4959?
1.4959 is a solid-solution strengthened austenitic Fe-Ni-Cr alloy for sustained service between about 600 °C and 900 °C in oxidising, reducing, carburising and nitriding atmospheres. It is used where ordinary austenitic stainless steels no longer hold their strength.
The grade belongs to the Alloy 800 family. All three members of that family share roughly the same 32 Ni / 21 Cr chemistry. What separates them is how tightly carbon, grain size and the aluminium plus titanium addition are controlled, and that control is what determines creep and stress-rupture life. For this reason 1.4959 should not be substituted for 1.4876 without checking the design temperature first.
1.4876, 1.4958 and 1.4959 compared
X10NiCrAlTi32-21. General-purpose grade for corrosion and oxidation resistance, normally used up to about 600 °C. No coarse-grain requirement.
X5NiCrAlTi31-20. Controlled carbon and a coarse grain size, ASTM No. 5 or coarser, to develop creep and rupture strength above 600 °C.
X8NiCrAlTi32-21. Everything 800H requires, plus a controlled Al + Ti window of 0.85 to 1.20 % under ASTM. Highest creep-rupture strength and best long-term stability of the three.
02 / Cross referenceDesignations and international equivalents
1.4959 appears under a different name in every standards system. The table below lists the designations we work from when reading a customer specification.
| System | Designation | Notes |
|---|---|---|
| EN material number | 1.4959 | Primary European identifier |
| EN chemical name | X8NiCrAlTi32-21 | Per EN 10095 and EN 10302 |
| UNS (USA) | N08811 | ASTM B564, B408, B409 |
| Trade names | Incoloy 800HT, Nicrofer 3220 HT | Registered marks of their owners |
| ISO | FeNi32Cr21AlTi-HT | ISO 9725 forgings |
| AFNOR (France) | Z 8 NC 33-21 | |
| BS (UK) | NA 15 | BS 3076 rod and bar |
| DIN | 17460 | Rod, bar and forgings |
| VdTUV | Werkstoffblatt 412 | Pressure equipment approval |
Standards we forge and test to
- EN 10095, heat-resisting steels and nickel alloys. Base standard for 1.4959 bar and forgings.
- EN 10302, creep-resisting steels, nickel and cobalt alloys.
- ASTM B564 and ASME SB-564, nickel alloy forgings in UNS N08811.
- ASTM B408 and ASME SB-408, rod and bar.
- ISO 9725, nickel and nickel alloy forgings.
- DIN 17460, SEW 470, VdTUV 412, European pressure equipment routes.
03 / ChemistryChemical composition of 1.4959
The composition below is the EN 10095 requirement. Every heat is analysed on the ladle and on the product, and both analyses appear on the EN 10204 certificate.
| C | Si max | Mn max | P max | S max | Cr | Ni |
|---|---|---|---|---|---|---|
| 0.05-0.10 | 0.70 | 1.50 | 0.015 | 0.010 | 19.0-22.0 | 30.0-34.0 |
| Al | Ti | Co max | Cu max | N max | Fe |
|---|---|---|---|---|---|
| 0.25-0.65 | 0.25-0.65 | 0.50 | 0.50 | 0.03 | Balance |
04 / PropertiesMechanical and physical properties
Values below apply to the solution-annealed condition at room temperature. Specified minimums govern acceptance. The typical column shows the range our heats normally return.
| Property | EN 10095 requirement | ASTM B564 minimum | Typical from our heats |
|---|---|---|---|
| Tensile strength Rm | 500-750 MPa | 450 MPa (65 ksi) | 520-600 MPa |
| Yield strength Rp0.2 | 170 MPa min | 170 MPa (25 ksi) | 200-260 MPa |
| Elongation A | 30 % min | 30 % | 40-55 % |
| Hardness | Not specified | Not specified | 192 HB max |
| Grain size, 800HT requirement | ASTM No. 5 or coarser | ||
| Property | Value |
|---|---|
| Density | 7.94 g/cm³ (0.287 lb/in³) |
| Melting range | 1357-1385 °C |
| Modulus of elasticity | 196 GPa |
| Specific heat | 460 J/(kg·K) |
| Thermal conductivity | 11.5 W/(m·K) |
| Mean thermal expansion, 20-100 °C | 14.4 × 10-6 /K |
| Electrical resistivity | 0.99 µΩ·m approx. |
| Magnetic response | Essentially non-magnetic, μ 1.01 approx. |
Service temperature and creep behaviour
ASTM B564 places UNS N08811 in the group normally employed above 593 °C (1100 °F), where resistance to creep and rupture is required.
- 600 to 900 °C. The normal design range. Creep and stress-rupture data govern wall thickness and section size.
- Up to about 1100 °C. Possible for limited exposure where metal loss is acceptable.
- Above about 925 °C. Oxidation and carburisation rates rise sharply. Cyclic service is harsher than static service, so confirm the atmosphere, cycle count and required life before selecting the grade.
05 / ProcessForging and heat treatment route
1.4959 has a narrow hot-working window, so the forging and annealing route has a direct effect on the properties obtained.
| Stage | Parameters |
|---|---|
| Melting | EAF plus VOD (argon-oxygen or vacuum-oxygen decarburisation). ESR remelting available where a cleaner, more homogeneous ingot is specified. |
| Ingot and billet | Homogenised before breakdown to disperse Ti and Al segregation. |
| Forging temperature | 1010-1205 °C |
| Finishing temperature | Kept above 900 °C. Finishing too cold produces duplex grain and non-uniform properties. |
| Reduction ratio | Minimum 3:1 forging ratio as standard, higher on request for critical sections. |
| Ring rolling | Seamless rolled rings produced on radial-axial mills after upsetting and punching. |
| Solution annealing | 1150-1180 °C followed by rapid cooling |
| Grain size control | Anneal cycle aimed at ASTM No. 5 or coarser, as required for 800HT. |
| Machining | As-forged, rough machined with agreed allowance, or finish machined to drawing. |
Welding 1.4959
1.4959 is welded by GTAW, GMAW, SMAW and SAW. Nickel-based fillers are used, typically ERNiCr-3 for bare wire and ENiCrFe-2 or ENiCrFe-3 for coated electrodes. Heat input and interpass temperature should be kept low. Post-weld heat treatment is not normally required for high-temperature service. A re-solution anneal is specified only where maximum creep performance or full stress relief is needed.
06 / CapabilityProduct forms and size range
All forms below are produced to customer drawing. There is no standard catalogue.
07 / QualityTesting, NDT and certification
Every 1.4959 forging leaves the works with a traceable heat number and a full test record. The scope below is run as standard. Additional tests called out in your specification can be added at enquiry stage.
| Test | Standard or method |
|---|---|
| Chemical analysis | Ladle and product analysis, spectrometric. PMI on request. |
| Tensile test | Room temperature and elevated temperature, per EN ISO 6892-1 and 6892-2 |
| Hardness | Brinell, per EN ISO 6506 |
| Grain size | ASTM E112, No. 5 or coarser for 800HT |
| Ultrasonic testing | EN 10228-3, SEP 1921 or ASTM A388, quality class to customer specification |
| Liquid penetrant | EN ISO 3452 or ASTM E165, on request |
| Intergranular corrosion | ASTM A262, practice as specified, on request |
| Dimensional | 100 % against the released drawing |
| Certification | EN 10204 3.1 as standard. EN 10204 3.2 witnessed by TUV, SGS, BV, DNV or Lloyd's Register on request. |
08 / ApplicationsWhere 1.4959 forgings are used
1.4959 is specified for plant that runs at temperature for long periods. The main applications we forge for are set out below.
Petrochemical and chemical processing
Ethylene cracking furnace components, pigtails and headers, reformer outlet manifolds, hydrocarbon processing internals, and equipment for nitric acid, acetic anhydride and oxo-alcohol plants. Usual forms are rolled rings, tube sheets, forged flanges, nozzles and pipe blanks.
Power generation and heat treatment
Superheater and reheater headers, steam generator components, radiant tube supports, furnace retorts and muffles, and fixtures and baskets that cycle through carburising atmospheres. Usual forms are shafts, discs, sleeves and rings.
Heat exchangers and pressure equipment
Shell-and-tube exchanger tube sheets, channel covers, forged flanges and shell rings for high-temperature service, produced to PED and ASME routes where required.
Valves and rotating equipment
Valve bodies, bonnets, stems and seat rings for hot service, compressor and turbine components, and gearbox and drive shafts operating above the range of austenitic stainless steels.
Nuclear and specialist plant
Structural and heat-transfer components where long-term metallurgical stability under thermal exposure is the governing requirement.
09 / OrderingHow to get a quotation
Send the five items below and you will normally have a price and a lead time within one working day.
- Drawing or dimensions. 2D drawing, 3D model, or rough forging dimensions (OD, ID, height, length) in PDF, DWG or STEP.
- Delivery condition. As-forged, rough machined with allowance, or finish machined to drawing.
- Governing standard. EN 10095, ASTM B564, ASME SB-564, or your own specification.
- Testing and certification. UT class and standard, mechanical test temperature, grain size requirement, EN 10204 3.1 or 3.2.
- Quantity and destination. Piece count, required date, destination port.
Request a quotation for 1.4959 forgings
Jiangyin Jiangnan Metal Co., Ltd., open-die forging factory, Jiangyin, Jiangsu, China. Enquiries answered in English or Chinese.
- sales@steelforgepieces.com
- Telephone, WhatsApp, WeChat
- +86 189 2135 9659
- Works address
- No.1 Chengxiqiao Road, Zhouzhuang Town,
Jiangyin City, Jiangsu Province, China - Nearest port
- Shanghai or Zhangjiagang
10 / FAQFrequently asked questions about 1.4959
What is 1.4959 material?
EN 1.4959 is the European material number for X8NiCrAlTi32-21, a nickel-iron-chromium heat-resisting alloy containing roughly 30 to 34 % nickel, 19 to 22 % chromium and balance iron, with controlled additions of aluminium and titanium. It is the European equivalent of UNS N08811, commonly known as Alloy 800HT or Incoloy 800HT, and is covered by EN 10095.
Is 1.4959 the same as Incoloy 800HT?
In practical terms, yes. 1.4959 / X8NiCrAlTi32-21 is the EN designation and UNS N08811 is the American designation for the same alloy, sold under the trade names Incoloy 800HT and Nicrofer 3220 HT. The chemistry limits differ slightly. EN 10095 allows carbon 0.05 to 0.10 %, while ASTM requires 0.06 to 0.10 % and a combined Al + Ti content of 0.85 to 1.20 %. Jiangyin Jiangnan Metal can forge to either limit set. Tell us which standard governs.
What is the difference between 1.4876, 1.4958 and 1.4959?
They are three members of the same Alloy 800 family. 1.4876 (X10NiCrAlTi32-21, Alloy 800, UNS N08800) is the general-purpose grade used mainly below about 600 °C. 1.4958 (X5NiCrAlTi31-20, Alloy 800H, UNS N08810) has controlled carbon and a coarse grain size for creep service above 600 °C. 1.4959 (X8NiCrAlTi32-21, Alloy 800HT, UNS N08811) adds a controlled Al + Ti range on top of the 800H requirements, which gives the highest creep and stress-rupture strength of the three.
What is the maximum service temperature of 1.4959?
1.4959 is normally specified above 593 °C (1100 °F), where creep and rupture resistance govern design. Its practical creep design range is about 600 to 900 °C. It can see roughly 1100 °C for limited periods where metal loss is acceptable, but oxidation and carburisation rates rise sharply above about 925 °C, so the actual limit must be set from the service atmosphere and the required life.
Which standards cover 1.4959 forgings?
EN 10095 covers heat-resisting steels and nickel alloys including 1.4959, EN 10302 covers creep-resisting grades, and DIN 17460 and VdTUV Werkstoffblatt 412 are also applied in Europe. On the American side, ASTM B564 and ASME SB-564 cover nickel alloy forgings in UNS N08811, ASTM B408 covers rod and bar, and ISO 9725 covers forgings. We supply to EN 10095 as standard and to ASTM B564 on request.
What is the chemical composition of 1.4959?
Per EN 10095: carbon 0.05 to 0.10 %, silicon max 0.70 %, manganese max 1.5 %, phosphorus max 0.015 %, sulphur max 0.010 %, chromium 19.0 to 22.0 %, nickel 30.0 to 34.0 %, aluminium 0.25 to 0.65 %, titanium 0.25 to 0.65 %, cobalt max 0.5 %, copper max 0.5 %, nitrogen max 0.03 %, iron balance.
What size 1.4959 seamless rolled rings can you supply?
We produce 1.4959 seamless rolled rings from approximately 200 mm to 5000 mm outside diameter, single-piece weights from about 20 kg up to 30 tonnes, and forged bars from about 80 mm to 1200 mm diameter. Rings outside this range can often be produced as open-die forged and bored blanks. Send the drawing and we will confirm.
Is 1.4959 weldable?
Yes. 1.4959 is welded by GTAW, GMAW, SMAW and SAW using nickel-based fillers, typically ERNiCr-3 for bare wire and ENiCrFe-2 or ENiCrFe-3 for coated electrodes. Interpass temperature and heat input should be kept low. Post-weld heat treatment is not normally required for high-temperature service. A re-solution anneal is specified only where maximum creep performance or full stress relief is needed.
What certificates are supplied with 1.4959 forgings?
Every forging is supplied with an EN 10204 3.1 mill certificate covering heat number, chemical analysis, heat treatment record, mechanical test results and NDT results. EN 10204 3.2 certification witnessed by a third party, such as TUV, SGS, BV, DNV or Lloyd's Register, is available on request, along with PMI, grain size reports and ultrasonic test reports to EN 10228-3, SEP 1921 or ASTM A388.
Who supplies 1.4959 open-die forgings in China?
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, producing 1.4959 (Alloy 800HT) forged rings, shafts, flanges, discs, sleeves and bars to customer drawings. Send enquiries to sales@steelforgepieces.com or call +86 189 2135 9659.