Stainless Steel 1.4959
EN 1.4959 · UNS N08811 · also Incoloy 800HT
1.4959 (X8NiCrAlTi32-21, N08811, Incoloy 800HT) is the higher aluminium-plus-titanium version of Alloy 800H, giving further enhanced creep-rupture strength for the most demanding high-temperature furnace and process duty, rated here to 1100 °C.
Reference datasheet — 1.4959 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the SA condition
1.4959 tempers and conditions
1.4959 is supplied in 4 conditions, soft to hard. SA is the default FabDigit quotes; the values on this page are for it.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Hot finished and solution annealed | Choose for large-diameter bar, rings and forged furnace hardware where a hot-finished surface is acceptable. | 235 | 540 | 45 | 150 HB | 1.7 % IACS |
SADefault Solution annealed | Standard supply condition for plate, sheet, tube and pipe; the coarse-grain anneal is what gives 800HT its creep-rupture rating. | 240 | 550 | 47 | 145 HB | — |
Cold drawn and solution annealed | Pick for close-tolerance bright bar and small-bore instrument/heater tubing that must still meet the annealed creep rating. | 250 | 560 | 45 | 150 HB | 1.7 % IACS |
Cold worked | Only for room-temperature strength or springback needs — cold work is lost above ~600 °C and is not permitted for creep-rated service. | 620 | 760 | 12 | 21 HRC | 1.7 % IACS |
What is 1.4959?
1.4959 (X8NiCrAlTi32-21, N08811, Incoloy 800HT) is the higher aluminium-plus-titanium version of Alloy 800H, giving further enhanced creep-rupture strength for the most demanding high-temperature furnace and process duty, rated here to 1100 °C. It is used for tubes, piping and furnace hardware and is supplied solution annealed as hot-finished, cold-drawn and cold-worked product. Room-temperature strength is moderate (240 MPa yield, 550 MPa tensile, 47 % elongation) and the coarse grain that carries the creep performance must be restored by annealing at 1150 °C or above after heavy cold work. Alloy 800H (1.4958) is the lower-cost choice when creep life is less critical. 1.4959 has a density of 7.94 g/cm³ (0.287 lb/in³), heavier than 78% of stainless steel grades. It melts at 1,357°C (2,475 °F). 1.4959 has a yield strength of 240 MPa (34.8 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 96% of stainless steel grades. Elongation at break is 47% and the elastic modulus is 196 GPa (28.4 Msi).
What is 1.4959 used for?
- ethylene furnace tubes
- high-temperature process piping
- heat treatment retorts
- radiant coil supports
Advantages
- High service temperature — 1,100°C (2,012 °F), better than 96% of stainless steel grades
- Ductile — tolerates forming and impact — 47%, better than 83% of stainless steel grades
- Forms and bends easily — 70/100, better than 79% of stainless steel grades
Limitations
- High embodied carbon — 8.5 kg CO₂/kg, worse than 99% of stainless steel grades
- Poor heat conductor — 11.5 W/m·K (6.64 BTU/hr·ft·°F), worse than 97% of stainless steel grades
- Low strength — 240 MPa (34.8 ksi), worse than 96% of stainless steel grades
- Low electrical conductivity — 1.7 % IACS, worse than 93% of stainless steel grades
1.4959 properties
Typical room-temperature values for 1.4959-SA; bars are the position among stainless steel grades.
Physical3
1.4959 has a density of 7.94 g/cm³ (0.287 lb/in³), heavier than 78% of stainless steel grades. It melts at 1,357°C (2,475 °F).
Mechanical14
1.4959 has a yield strength of 240 MPa (34.8 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 96% of stainless steel grades. Elongation at break is 47% and the elastic modulus is 196 GPa (28.4 Msi).
Thermal6
1.4959 is rated for continuous service to 1,100°C (2,012 °F). It conducts heat at 11.5 W/m·K (6.64 BTU/hr·ft·°F), worse than 97% of stainless steel grades. Thermal expansion is 14.4 µm/m·K (8 µin/in·°F).
Electrical3
1.4959 conducts electricity at 1.7 % IACS, worse than 93% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is very good (72/100), better than 73% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.4959 takes about 95 MJ of energy and emits 8.5 kg of CO₂ — more than 96% of stainless steel grades. Typical recycled content is 35%.
Manufacturability7
1.4959's machinability is poor (30/100, worse than 70% of stainless steel grades); weldability very good (75/100); formability very good (70/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the stainless steel family
Yield strength against density for every stainless steel grade FabDigit runs. 1.4959 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 1.4959
Is 1.4959 easy to machine?
Machine like a gummy austenitic superalloy: rigid setup, positive-rake carbide, 15–30 m/min, heavy constant feed to cut under the work-hardened layer, and copious sulphur-free coolant.
Can 1.4959 be welded?
Readily welded by GTAW/GMAW/SMAW with matching Ni-Fe-Cr filler (ERNiCr-3 / Alloy 82 or 617 for the hottest service); low heat input, no preheat and no post-weld heat treatment required.
Can 1.4959 be formed, bent or molded?
Cold forms well but work-hardens fast and the coarse grain can give orange peel — hot work 1150–900 °C and re-anneal at ≥1150 °C after heavy cold forming to restore the creep-rated grain size.
1.4959 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Ni | 30 – 35 | 32 |
| Cr | 19 – 23 | 21 |
| Ccontrolled high carbon for creep strength | 0.06 – 0.1 | 0.08 |
| Al | 0.15 – 0.6 | 0.5 |
| Ti | 0.15 – 0.6 | 0.5 |
| Al+Tikey distinction of 800HT vs 800H | 0.85 – 1.2 | 1 |
| Mn | ≤ 1.5 | 0.8 |
| Si | ≤ 1 | 0.4 |
| Cu | ≤ 0.75 | 0.3 |
| S | ≤ 0.02 | 0.01 |
| Fe39.5 % min per UNS N08811 | ≥ 39.5 (balance) |
What surface finishes work on 1.4959?
Pickle in HNO3-HF or grit blast plus passivation to remove the tenacious Al/Ti-rich scale; not anodisable, and the protective service scale reforms in operation.
Surface treatments FabDigit runs on stainless steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Passivation
Organic Coating
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Stainless Steel 1.4959 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- N08811
- EN / DIN / Werkstoff-Nr.
- X8NiCrAlTi32-21
- Trade names
- Incoloy 800HT
How much does 1.4959 cost?
1.4959 is a high-cost stainless steel ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
1.4959 — frequently asked
What is 1.4959 used for?
1.4959 is typically used for ethylene furnace tubes, high-temperature process piping, heat treatment retorts and radiant coil supports. In short: highest creep strength of 800 family; controlled Al+Ti 800HT; reformer and cracker tubing alloy.
What is the yield strength of 1.4959?
1.4959 has a typical yield strength of 240 MPa (34.8 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 96% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is 1.4959 easy to machine?
Not especially — machinability is rated poor (30/100, worse than 70% of stainless steel grades). Machine like a gummy austenitic superalloy: rigid setup, positive-rake carbide, 15–30 m/min, heavy constant feed to cut under the work-hardened layer, and copious sulphur-free coolant.
Can 1.4959 be welded?
Yes — weldability is rated very good (75/100). Readily welded by GTAW/GMAW/SMAW with matching Ni-Fe-Cr filler (ERNiCr-3 / Alloy 82 or 617 for the hottest service); low heat input, no preheat and no post-weld heat treatment required.
What surface finishes work on 1.4959?
Pickle in HNO3-HF or grit blast plus passivation to remove the tenacious Al/Ti-rich scale; not anodisable, and the protective service scale reforms in operation.
Can 1.4959 be formed, bent or molded?
Cold forms well but work-hardens fast and the coarse grain can give orange peel — hot work 1150–900 °C and re-anneal at ≥1150 °C after heavy cold forming to restore the creep-rated grain size.
What is the maximum service temperature of 1.4959?
1.4959 is rated for continuous use to about 1,100°C (2,012 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 1.4959-SA and 1.4959-CW?
SA is the default condition — standard supply condition for plate, sheet, tube and pipe; the coarse-grain anneal is what gives 800HT its creep-rupture rating. CW: only for room-temperature strength or springback needs — cold work is lost above ~600 °C and is not permitted for creep-rated service. Yield strength is 240 MPa in SA versus 620 MPa in CW.
How much does 1.4959 cost?
1.4959 is a high-cost stainless steel ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM B409 / B408 / B407 — UNS N08811 plate, bar and tube — ASTM International (2023)
- EN 10095 / VdTÜV-Wb 412 — X8NiCrAlTi32-21 (1.4959) — CEN / VdTÜV (2018)
- INCOLOY alloy 800H & 800HT technical bulletin — Special Metals Corporation (2004)
- ASM Handbook Vol. 1 — Heat-Resistant Iron-Nickel-Chromium Alloys — ASM International (1990)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.