Stainless Steel 1.4945 +AT (Solution annealed)
Heat-treated state · default condition
EN 1.4945
Standard stocked condition for tube, pipe and bar: maximum ductility, best weld and bend behaviour, adequate creep strength for service up to ~700 °C.
Values for the +AT condition
Other 1.4945 tempers and conditions
1.4945 is listed in 3 conditions; see the grade overview at 1.4945.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
+ATDefaultThis page Solution annealed | Standard stocked condition for tube, pipe and bar: maximum ductility, best weld and bend behaviour, adequate creep strength for service up to ~700 °C. | 320 | 680 | 40 | 175 HB | — |
Warm worked | Choose for superheater/reheater tubing where the substructure introduced by warm working gives markedly higher creep rupture strength at 600–700 °C. | 470 | 780 | 28 | 21 HRC | — |
Solution annealed then cold drawn bar/tube | Cold-drawn bar and small-diameter tube for machined turbine and fastener parts where dimensional accuracy and higher room-temperature strength matter more than ductility. | 600 | 830 | 20 | 24 HRC | — |
What is 1.4945 +AT?
1.4945 +AT is 1.4945 heat treated to +AT — standard stocked condition for tube, pipe and bar: maximum ductility, best weld and bend behaviour, adequate creep strength for service up to ~700 °C. 1.4945 +AT has a yield strength of 320 MPa (46.4 ksi) and a tensile strength of 680 MPa (98.6 ksi) — weaker than 60% of stainless steel grades. Elongation at break is 40% and the elastic modulus is 197 GPa (28.6 Msi). 1.4945 +AT has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,390°C (2,534 °F).
Advantages
- Tough — resists crack growth — 200 MPa·√m (182 ksi·√in), better than 86% of stainless steel grades
Limitations
- Needs corrosion protection — 50/100, worse than 78% of stainless steel grades
- Low electrical conductivity — 2 % IACS, worse than 77% of stainless steel grades
1.4945 +AT properties
Typical room-temperature values for 1.4945 +AT; 17 are specific to this condition. Other listed values are 1.4945 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
1.4945 +AT has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,390°C (2,534 °F).
Mechanical16
1.4945 +AT has a yield strength of 320 MPa (46.4 ksi) and a tensile strength of 680 MPa (98.6 ksi) — weaker than 60% of stainless steel grades. Elongation at break is 40% and the elastic modulus is 197 GPa (28.6 Msi).
Thermal6
1.4945 +AT is rated for continuous service to 700°C (1,292 °F). It conducts heat at 14.5 W/m·K (8.38 BTU/hr·ft·°F), worse than 72% of stainless steel grades. Thermal expansion is 16 µm/m·K (8.89 µin/in·°F).
Electrical3
1.4945 +AT conducts electricity at 2 % IACS, worse than 77% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (50/100), worse than 78% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.4945 +AT takes about 57 MJ of energy and emits 5.2 kg of CO₂ — more than 62% of stainless steel grades. Typical recycled content is 55%.
Manufacturability7
1.4945 +AT's machinability is poor (32/100, worse than 62% of stainless steel grades); weldability good (65/100); formability good (60/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.4945 +AT
Is 1.4945 easy to machine?
Machine like a nitrogen-alloyed austenitic: rigid setups, sharp positive-rake carbide, heavy positive feed to cut under the work-hardened layer, generous high-pressure coolant, ~30–40 % of AISI 1212 speeds.
Can 1.4945 be welded?
Weld with GTAW/SMAW using matching or Nb-stabilised high-Ni filler, low heat input and interpass below ~150 °C; post-weld solution annealing restores properties for warm-worked tubing.
Can 1.4945 be formed, bent or molded?
Hot work at roughly 1150–1200 °C and solution anneal at ~1150–1200 °C with rapid cooling; cold and warm forming need high forces and generous allowance for springback due to strong work hardening.
What surface finishes work on 1.4945?
Pickle and passivate (or electropolish) after hot work and welding to restore the oxide-free passive film; no anodising — protective Cr₂O₃/oxide scale forms in service.
1.4945 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 |
|---|---|---|
| CX6 designation | 0.04 – 0.08 | 0.06 |
| Si | ≤ 0.6 | 0.4 |
| Mn | ≤ 2 | 1.2 |
| Pimpurity limit | ≤ 0.04 | — |
| Simpurity limit | ≤ 0.02 | — |
| Cr | 15.5 – 17.5 | 16 |
| Ni | 15.5 – 17.5 | 16 |
| Wsolid-solution creep strengthener | 1 – 2 | 1.5 |
| NbMX carbonitride precipitation, stabilisation | 0.4 – 1 | 0.7 |
| Nnitrogen strengthening | 0.05 – 0.15 | 0.1 |
| Fe | balance | — |
1.4945 +AT — frequently asked
What is 1.4945 +AT used for?
1.4945 +AT is typically used for gas turbine components, power plant superheater tubing, high-temperature fasteners and boiler components. In short: W and Nb creep-resistant austenitic; 700 °C turbine grade; limited mill availability.
What is the yield strength of 1.4945 +AT?
1.4945 +AT has a typical yield strength of 320 MPa (46.4 ksi) and a tensile strength of 680 MPa (98.6 ksi) — weaker than 60% of stainless steel grades. Strength varies by condition: see the 3 listed tempers.
Is 1.4945 +AT easy to machine?
Not especially — machinability is rated poor (32/100, worse than 62% of stainless steel grades). Machine like a nitrogen-alloyed austenitic: rigid setups, sharp positive-rake carbide, heavy positive feed to cut under the work-hardened layer, generous high-pressure coolant, ~30–40 % of AISI 1212 speeds.
Can 1.4945 +AT be welded?
Yes — weldability is rated good (65/100). Weld with GTAW/SMAW using matching or Nb-stabilised high-Ni filler, low heat input and interpass below ~150 °C; post-weld solution annealing restores properties for warm-worked tubing.
What surface finishes work on 1.4945 +AT?
Pickle and passivate (or electropolish) after hot work and welding to restore the oxide-free passive film; no anodising — protective Cr₂O₃/oxide scale forms in service.
Can 1.4945 +AT be formed, bent or molded?
Hot work at roughly 1150–1200 °C and solution anneal at ~1150–1200 °C with rapid cooling; cold and warm forming need high forces and generous allowance for springback due to strong work hardening.
What is the maximum service temperature of 1.4945 +AT?
1.4945 +AT is rated for continuous use to about 700°C (1,292 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- EN 10302 — Creep resisting steels, nickel and cobalt alloys — CEN (2008)
- EN 10088-1 — Stainless steels: list of stainless steels — CEN (2014)
- EN 10216-5 — Seamless steel tubes for pressure purposes: stainless steel tubes — CEN (2021)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.13B — Corrosion: Materials — ASM International (2005)
- SMM / Mysteel (2025)
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.