Stainless Steel 1.4959 CD-A
Heat-treated state
EN 1.4959 · UNS N08811 · also Incoloy 800HT
CD-A = 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.
Values for the CD-A condition
Other 1.4959 tempers and conditions
1.4959 is listed in 4 conditions; see the grade overview at 1.4959.
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 | — |
CD-AThis page 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 CD-A?
1.4959 CD-A is 1.4959 heat treated to CD-A — pick for close-tolerance bright bar and small-bore instrument/heater tubing that must still meet the annealed creep rating. 1.4959 CD-A has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 91% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 196 GPa (28.4 Msi). 1.4959 CD-A 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). SA is the default condition FabDigit quotes; CD-A is available on request or by drawing note.
Advantages
- High service temperature — 1,100°C (2,012 °F), better than 96% of stainless steel grades
- Ductile — tolerates forming and impact — 45%, better than 76% of stainless steel grades
- Forms and bends easily — 68/100, better than 75% 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 electrical conductivity — 1.7 % IACS, worse than 93% of stainless steel grades
- Low strength — 250 MPa (36.3 ksi), worse than 91% of stainless steel grades
1.4959 CD-A properties
Typical room-temperature values for 1.4959 CD-A; 21 are specific to this condition. Other listed values are 1.4959 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
1.4959 CD-A 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 CD-A has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 91% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 196 GPa (28.4 Msi).
Thermal6
1.4959 CD-A 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 CD-A 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 CD-A 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 CD-A's machinability is poor (32/100, worse than 62% of stainless steel grades); weldability very good (75/100); formability good (68/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.4959 CD-A
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.
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.
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) | — |
1.4959 CD-A — frequently asked
What is 1.4959 CD-A used for?
1.4959 CD-A 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 CD-A?
1.4959 CD-A has a typical yield strength of 250 MPa (36.3 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 91% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is 1.4959 CD-A easy to machine?
Not especially — machinability is rated poor (32/100, worse than 62% 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 CD-A 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 CD-A?
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 CD-A 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 CD-A?
1.4959 CD-A 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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.