Stainless Steel 1.3975-AT (Solution annealed)
Precip hard · default condition
EN 1.3975
Standard delivery condition for pressure and corrosion-service castings: maximum ductility, carbides dissolved, minimum magnetic permeability.
Values for the AT condition
Other 1.3975 tempers and conditions
1.3975 is listed in 4 conditions; see the grade overview at 1.3975.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ATDefaultThis page Solution annealed | Standard delivery condition for pressure and corrosion-service castings: maximum ductility, carbides dissolved, minimum magnetic permeability. | 260 | 540 | 35 | 170 HB | 2.2 % IACS |
Stress relieved | Used only to relieve machining/welding residual stress on dimensionally critical parts; kept below sensitisation range. | 265 | 535 | 33 | 172 HB | 2.2 % IACS |
Solution annealed and hot isostatically pressed | For investment castings needing closed internal porosity: best fatigue life, impact toughness and leak tightness at a cost premium. | 270 | 560 | 42 | 170 HB | 2.2 % IACS |
As fabricated | Cheapest condition for non-corrosive, non-pressure structural castings where dendritic segregation and residual stresses are acceptable. | 280 | 500 | 22 | 185 HB | 2.2 % IACS |
What is 1.3975-AT?
1.3975-AT is 1.3975 in the AT condition — standard delivery condition for pressure and corrosion-service castings: maximum ductility, carbides dissolved, minimum magnetic permeability. 1.3975-AT has a yield strength of 260 MPa (37.7 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 84% of stainless steel grades. Elongation at break is 35% and the elastic modulus is 195 GPa (28.3 Msi). 1.3975-AT has a density of 7.8 g/cm³ (0.282 lb/in³), heavier than 50% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Limitations
- Low strength — 260 MPa (37.7 ksi), worse than 84% of stainless steel grades
- Hard to polish — 60/100, worse than 80% of stainless steel grades
1.3975-AT properties
Typical room-temperature values for 1.3975-AT; 23 are specific to this condition. Other listed values are 1.3975 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
1.3975-AT has a density of 7.8 g/cm³ (0.282 lb/in³), heavier than 50% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical16
1.3975-AT has a yield strength of 260 MPa (37.7 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 84% of stainless steel grades. Elongation at break is 35% and the elastic modulus is 195 GPa (28.3 Msi).
Thermal6
1.3975-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 17 µm/m·K (9.44 µin/in·°F).
Electrical3
1.3975-AT conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (55/100), worse than 71% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.3975-AT takes about 53 MJ of energy and emits 4.8 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 70%.
Manufacturability7
1.3975-AT's machinability is poor (33/100, worse than 57% of stainless steel grades); weldability good (60/100); formability fair (35/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.3975-AT
Is 1.3975 easy to machine?
Gummy and strongly work-hardening: use rigid setups, sharp positive-rake carbide, heavy positive feed, 60–110 m/min and flood coolant; never dwell or rub.
Can 1.3975 be welded?
Weldable with 308L/309L or high-Mn austenitic filler using TIG/MMA, low heat input, no preheat, interpass <150 °C; hot-crack risk rises with Si, so keep dilution and restraint low.
Can 1.3975 be formed, bent or molded?
Supplied as sand or investment castings — design 2–3 % shrinkage, generous fillets and directional feeding; solution anneal + water quench after casting for full corrosion performance.
What surface finishes work on 1.3975?
Pickle and passivate (HNO3-based) after grinding or welding to restore the chromium oxide film; polishes to a fair satin/bright finish, electropolishing helps on porosity-free HIP parts.
1.3975 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 |
|---|---|---|
| Clow-carbon (X3) to limit carbide sensitisation | ≤ 0.05 | 0.03 |
| Siraises fluidity and scaling resistance | 1 – 2.5 | 1.8 |
| Mnaustenite stabiliser replacing part of the Ni | 7 – 9 | 8 |
| Cr | 16 – 18 | 17 |
| Ni | 8 – 10 | 9 |
| Noptional, strengthens and stabilises austenite | ≤ 0.2 | 0.1 |
| P | ≤ 0.05 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
1.3975-AT — frequently asked
What is 1.3975-AT used for?
1.3975-AT is typically used for general corrosion-resistant castings, pump housings, valve bodies for water and mild chemical service, machinery and structural castings, fittings and flanged bodies and elevated-temperature brackets and supports. In short: nickel-saving cast austenitic; lower-cost CF8 substitute; moderate corrosion resistance.
What is the yield strength of 1.3975-AT?
1.3975-AT has a typical yield strength of 260 MPa (37.7 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 84% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is 1.3975-AT easy to machine?
Not especially — machinability is rated poor (33/100, worse than 57% of stainless steel grades). Gummy and strongly work-hardening: use rigid setups, sharp positive-rake carbide, heavy positive feed, 60–110 m/min and flood coolant; never dwell or rub.
Can 1.3975-AT be welded?
Yes — weldability is rated good (60/100). Weldable with 308L/309L or high-Mn austenitic filler using TIG/MMA, low heat input, no preheat, interpass <150 °C; hot-crack risk rises with Si, so keep dilution and restraint low.
What surface finishes work on 1.3975-AT?
Pickle and passivate (HNO3-based) after grinding or welding to restore the chromium oxide film; polishes to a fair satin/bright finish, electropolishing helps on porosity-free HIP parts.
Can 1.3975-AT be formed, bent or molded?
Supplied as sand or investment castings — design 2–3 % shrinkage, generous fillets and directional feeding; solution anneal + water quench after casting for full corrosion performance.
What is the maximum service temperature of 1.3975-AT?
1.3975-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.
What is the difference between 1.3975-AT and 1.3975-F?
AT is the default condition — standard delivery condition for pressure and corrosion-service castings: maximum ductility, carbides dissolved, minimum magnetic permeability. F: cheapest condition for non-corrosive, non-pressure structural castings where dendritic segregation and residual stresses are acceptable. Yield strength is 260 MPa in AT versus 280 MPa in F.
Sources
- EN 10283 — Corrosion resistant steel castings — CEN (2010)
- DIN EN 10027-2 Werkstoffnummern (1.39xx non-magnetic / Mn-alloyed austenitic group) — DIN (2015)
- ASM Handbook Vol.1 — Cast Stainless Steels — 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.