Stainless Steel 1.4347 +AT (Solution annealed)
Heat-treated state · default condition
EN 1.4347
Standard delivery condition of EN 10283 castings — balanced 50/50 ferrite/austenite, maximum corrosion resistance and toughness.
Values for the +AT condition
Other 1.4347 tempers and conditions
1.4347 is listed in 4 conditions; see the grade overview at 1.4347.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As fabricated | Only for non-critical, non-corrosive parts — unbalanced phase ratio and Cr-nitride precipitation cut toughness and pitting resistance. | 450 | 650 | 14 | 22 HRC | 2.1 % IACS |
As-welded deposit | Condition of production weld repairs made with 25Cr-N over-alloyed filler; properties reflect HAZ nitride formation, re-solution treatment preferred. | 460 | 670 | 18 | 21 HRC | 2.2 % IACS |
+ATDefaultThis page Solution annealed | Standard delivery condition of EN 10283 castings — balanced 50/50 ferrite/austenite, maximum corrosion resistance and toughness. | 480 | 690 | 26 | 20 HRC | 2.2 % IACS |
hot isostatically pressed then solution annealed and quenched | Choose for pressure-containing or fatigue-critical castings where shrinkage porosity must be eliminated. | 500 | 720 | 30 | 20 HRC | 2.2 % IACS |
What is 1.4347 +AT?
1.4347 +AT is 1.4347 heat treated to +AT — standard delivery condition of EN 10283 castings — balanced 50/50 ferrite/austenite, maximum corrosion resistance and toughness. 1.4347 +AT has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 690 MPa (100 ksi) — stronger than 75% of stainless steel grades. Elongation at break is 26% and the elastic modulus is 200 GPa (29 Msi). 1.4347 +AT has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Advantages
- High strength — 480 MPa (69.6 ksi), better than 75% of stainless steel grades
Limitations
- Limited service temperature — 300°C (572 °F), worse than 90% of stainless steel grades
- Limited formability — 25/100, worse than 78% of stainless steel grades
- Low fracture toughness — 90 MPa·√m (81.9 ksi·√in), worse than 75% of stainless steel grades
1.4347 +AT properties
Typical room-temperature values for 1.4347 +AT; 23 are specific to this condition. Other listed values are 1.4347 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
1.4347 +AT has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical17
1.4347 +AT has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 690 MPa (100 ksi) — stronger than 75% of stainless steel grades. Elongation at break is 26% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
1.4347 +AT is rated for continuous service to 300°C (572 °F). It conducts heat at 16 W/m·K (9.24 BTU/hr·ft·°F), better than 58% of stainless steel grades. Thermal expansion is 12.8 µm/m·K (7.11 µin/in·°F).
Electrical3
1.4347 +AT conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (65/100), better than 56% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.4347 +AT takes about 55 MJ of energy and emits 4.5 kg of CO₂ — more than 50% of stainless steel grades. Typical recycled content is 65%.
Manufacturability8
1.4347 +AT's machinability is fair (35/100, better than 51% of stainless steel grades); weldability good (55/100); formability poor (25/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.4347 +AT
Is 1.4347 easy to machine?
Machine like duplex: rigid setup, sharp coated carbide, 25–40 % lower cutting speed than CF8M, heavy positive feed to cut under the work-hardened skin, ample coolant.
Can 1.4347 be welded?
Weldable with over-alloyed 25Cr-N (or 2209-type) filler; keep interpass below ~150 °C, moderate heat input for phase balance, no post-weld stress relief in the 550–950 °C range — re-solution treat critical parts.
Can 1.4347 be formed, bent or molded?
Sand or investment cast; use generous risering and chills for the narrow freezing range, then always solution treat at 1050–1100 °C with fast water quench to dissolve nitrides.
What surface finishes work on 1.4347?
Grit-blast, pickle in HNO₃/HF and passivate for full corrosion performance; polishes reasonably but the two-phase structure etches unevenly — no anodizing (ferrous).
1.4347 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 |
|---|---|---|
| CGX4 = 0.04 % nominal | ≤ 0.06 | 0.04 |
| Si | ≤ 1 | 0.6 |
| Mn | ≤ 2 | 1 |
| P | ≤ 0.04 | — |
| S | ≤ 0.03 | — |
| Cr | 25 – 27 | 26 |
| Ni | 6 – 8 | 7 |
| Naustenite stabiliser, raises strength and pitting resistance | 0.12 – 0.22 | 0.16 |
| Moresidual only — grade is nominally Mo-free | ≤ 0.5 | — |
| Fe | balance | — |
1.4347 +AT — frequently asked
What is 1.4347 +AT used for?
1.4347 +AT is typically used for structural castings, valve bodies and heat exchanger components. In short: mo-free lean duplex; 480 MPa cast yield; good chloride SCC resistance.
What is the yield strength of 1.4347 +AT?
1.4347 +AT has a typical yield strength of 480 MPa (69.6 ksi) and a tensile strength of 690 MPa (100 ksi) — stronger than 75% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is 1.4347 +AT easy to machine?
Not especially — machinability is rated fair (35/100, better than 51% of stainless steel grades). Machine like duplex: rigid setup, sharp coated carbide, 25–40 % lower cutting speed than CF8M, heavy positive feed to cut under the work-hardened skin, ample coolant.
Can 1.4347 +AT be welded?
Yes — weldability is rated good (55/100). Weldable with over-alloyed 25Cr-N (or 2209-type) filler; keep interpass below ~150 °C, moderate heat input for phase balance, no post-weld stress relief in the 550–950 °C range — re-solution treat critical parts.
What surface finishes work on 1.4347 +AT?
Grit-blast, pickle in HNO₃/HF and passivate for full corrosion performance; polishes reasonably but the two-phase structure etches unevenly — no anodizing (ferrous).
Can 1.4347 +AT be formed, bent or molded?
Sand or investment cast; use generous risering and chills for the narrow freezing range, then always solution treat at 1050–1100 °C with fast water quench to dissolve nitrides.
What is the maximum service temperature of 1.4347 +AT?
1.4347 +AT is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 1.4347 +AT and 1.4347-F?
+AT is the default condition — standard delivery condition of EN 10283 castings — balanced 50/50 ferrite/austenite, maximum corrosion resistance and toughness. F: only for non-critical, non-corrosive parts — unbalanced phase ratio and Cr-nitride precipitation cut toughness and pitting resistance. Yield strength is 480 MPa in +AT versus 450 MPa in F.
Sources
- EN 10283 — Corrosion resistant steel castings — CEN (2010)
- EN 10213 — Steel castings for pressure purposes — CEN (2016)
- 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)
- Practical Guidelines for the Fabrication of Duplex Stainless Steels — IMOA (2014)
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.