Stainless Steel 1.4470-AC (Spheroidize annealed)
Heat-treated state
EN 1.4470 · UNS J92205 · ASTM A890 Grade 4A
Only for non-critical, non-corrosive decorative or structural parts — inter-metallic/nitride precipitates cut ductility, toughness and pitting resistance sharply.
Values for the AC condition
Other 1.4470 tempers and conditions
1.4470 is listed in 4 conditions; see the grade overview at 1.4470.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ACThis page Spheroidize annealed | Only for non-critical, non-corrosive decorative or structural parts — inter-metallic/nitride precipitates cut ductility, toughness and pitting resistance sharply. | 480 | 640 | 12 | 24 HRC | 2.2 % IACS |
SADefault Solution annealed ~1120 °C and water quenched | Standard and essentially the only certified supply condition for pressure-retaining duplex castings; gives balanced 50/50 microstructure and full corrosion resistance. | 500 | 700 | 30 | 21 HRC | — |
Hot isostatically pressed then solution annealed and quenched | Choose for thick-section subsea/pump castings where microporosity must be closed to raise fatigue life and NDE acceptance. | 520 | 730 | 34 | 22 HRC | 2.2 % IACS |
Centrifugally cast, solution annealed and quenched | For duplex pipe, sleeves and rings — directional solidification gives denser, slightly stronger and more uniform structure than static castings. | 530 | 730 | 28 | 22 HRC | 2.2 % IACS |
What is 1.4470-AC?
1.4470-AC is 1.4470 heat treated to AC — only for non-critical, non-corrosive decorative or structural parts — inter-metallic/nitride precipitates cut ductility, toughness and pitting resistance sharply. 1.4470-AC has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 640 MPa (92.8 ksi) — stronger than 75% of stainless steel grades. Elongation at break is 12% and the elastic modulus is 195 GPa (28.3 Msi). 1.4470-AC 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). SA is the default condition FabDigit quotes; AC is available on request or by drawing note.
Advantages
- High strength — 480 MPa (69.6 ksi), better than 75% of stainless steel grades
Limitations
- Limited service temperature — 200°C (392 °F), worse than 100% of stainless steel grades
- Limited ductility — 12%, worse than 95% of stainless steel grades
- Limited formability — 10/100, worse than 95% of stainless steel grades
- Low fracture toughness — 60 MPa·√m (54.6 ksi·√in), worse than 88% of stainless steel grades
- Difficult to weld — 50/100, worse than 77% of stainless steel grades
1.4470-AC properties
Typical room-temperature values for 1.4470-AC; 23 are specific to this condition. Other listed values are 1.4470 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
1.4470-AC 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).
Mechanical17
1.4470-AC has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 640 MPa (92.8 ksi) — stronger than 75% of stainless steel grades. Elongation at break is 12% and the elastic modulus is 195 GPa (28.3 Msi).
Thermal6
1.4470-AC is rated for continuous service to 200°C (392 °F). It conducts heat at 15 W/m·K (8.67 BTU/hr·ft·°F), worse than 59% of stainless steel grades. Thermal expansion is 13 µm/m·K (7.22 µin/in·°F).
Electrical3
1.4470-AC conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (58/100), worse than 62% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.4470-AC takes about 55 MJ of energy and emits 5 kg of CO₂ — more than 50% of stainless steel grades. Typical recycled content is 80%.
Manufacturability7
1.4470-AC's machinability is poor (28/100, worse than 79% of stainless steel grades); weldability fair (50/100); formability not recommended (10/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.4470-AC
Is 1.4470 easy to machine?
Machine like 2205 wrought duplex: rigid setup, sharp coated carbide, moderate speed (~60–90 m/min) with heavy positive feed to cut under the work-hardened skin, plus copious coolant.
Can 1.4470 be welded?
Readily weldable with 2209/25-9-4 filler or matching cast electrodes; keep heat input 0.5–2.5 kJ/mm, interpass <150 °C, and re-solution-anneal + water quench after major repair welds to restore phase balance.
Can 1.4470 be formed, bent or molded?
Sand, investment or centrifugal casting with good fluidity but ~2.2 % solidification shrinkage — needs generous risering and controlled pouring 1520–1560 °C; always follow with 1100–1150 °C solution treatment and rapid water quench.
What surface finishes work on 1.4470?
Pickle and passivate (HNO3–HF) after heat treatment to remove scale; polishes and electropolishes reasonably well, though the two phases can etch at slightly different rates.
1.4470 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 cast duplex | ≤ 0.03 | 0.02 |
| Si | ≤ 1 | 0.6 |
| MnASTM A995 Gr 4A allows ≤1.50 | ≤ 2 | 1 |
| P | ≤ 0.04 | — |
| SA995 Gr 4A ≤0.020 | ≤ 0.03 | — |
| CrA995 Gr 4A 21.0–23.5 | 21 – 23 | 22 |
| Ni | 4.5 – 6.5 | 5.5 |
| Mo | 2.5 – 3.5 | 3 |
| NA995 Gr 4A 0.10–0.30 | 0.12 – 0.2 | 0.16 |
| Curesidual limit per A995 | ≤ 1 | — |
| Fe | balance | — |
1.4470-AC — frequently asked
What is 1.4470-AC used for?
1.4470-AC is typically used for pump casings, valve bodies and seawater piping components. In short: general-purpose cast duplex; cast 2205 equivalent; widely available casting grade.
What is the yield strength of 1.4470-AC?
1.4470-AC has a typical yield strength of 480 MPa (69.6 ksi) and a tensile strength of 640 MPa (92.8 ksi) — stronger than 75% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is 1.4470-AC easy to machine?
Not especially — machinability is rated poor (28/100, worse than 79% of stainless steel grades). Machine like 2205 wrought duplex: rigid setup, sharp coated carbide, moderate speed (~60–90 m/min) with heavy positive feed to cut under the work-hardened skin, plus copious coolant.
Can 1.4470-AC be welded?
With care — weldability is rated fair (50/100). Readily weldable with 2209/25-9-4 filler or matching cast electrodes; keep heat input 0.5–2.5 kJ/mm, interpass <150 °C, and re-solution-anneal + water quench after major repair welds to restore phase balance.
What surface finishes work on 1.4470-AC?
Pickle and passivate (HNO3–HF) after heat treatment to remove scale; polishes and electropolishes reasonably well, though the two phases can etch at slightly different rates.
Can 1.4470-AC be formed, bent or molded?
Sand, investment or centrifugal casting with good fluidity but ~2.2 % solidification shrinkage — needs generous risering and controlled pouring 1520–1560 °C; always follow with 1100–1150 °C solution treatment and rapid water quench.
What is the maximum service temperature of 1.4470-AC?
1.4470-AC is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 1.4470-SA and 1.4470 CF-SA?
SA is the default condition — standard and essentially the only certified supply condition for pressure-retaining duplex castings; gives balanced 50/50 microstructure and full corrosion resistance. CF-SA: for duplex pipe, sleeves and rings — directional solidification gives denser, slightly stronger and more uniform structure than static castings. Yield strength is 500 MPa in SA versus 530 MPa in CF-SA.
Sources
- EN 10283 — Corrosion resistant steel castings — CEN (2010)
- ASTM A995/A995M — Castings, Austenitic-Ferritic (Duplex) Stainless Steel for Pressure-Containing Parts — ASTM (2020)
- ASTM A890/A890M — Castings, Iron-Chromium-Nickel-Molybdenum Corrosion-Resistant, Duplex — ASTM (2018)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Practical Guidelines for the Fabrication of Duplex Stainless Steels — IMOA (2014)
- GB/T 2100 / GB/T 12230 — SAC (2017)
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.