Stainless Steel 1.4474-AC (Spheroidize annealed)
Heat-treated state
EN 1.4474
Limit as-cast material to non-pressure, non-corrosive blanks or parts to be re-heat-treated; sigma phase and nitrides leave only 8 % elongation and unacceptable corrosion resistance in service.
Values for the AC condition
Other 1.4474 tempers and conditions
1.4474 is listed in 4 conditions; see the grade overview at 1.4474.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ACThis page Spheroidize annealed | Limit as-cast material to non-pressure, non-corrosive blanks or parts to be re-heat-treated; sigma phase and nitrides leave only 8 % elongation and unacceptable corrosion resistance in service. | 470 | 640 | 8 | 25 HRC | 2.1 % IACS |
Weld repaired and re-solution annealed + quenched | Apply after weld repair of casting defects: full re-solution annealing and quenching restores properties close to the solution-treated state at 515 MPa yield, and is the acceptance condition for repaired parts. | 515 | 720 | 20 | 23 HRC | 2.2 % IACS |
STDefault Solution annealed | Use the standard delivery state, solution annealed at 1040–1120 °C and water quenched, as the only treatment that guarantees the duplex phase balance, 520 MPa yield and corrosion resistance. | 520 | 730 | 22 | 22 HRC | — |
Hot isostatically pressed then solution annealed + quenched | Choose hot isostatic pressing followed by solution annealing and quenching for thin-wall or high-pressure sealing castings needing 100 % NDT acceptance; closing micro-porosity raises toughness and fatigue life. | 540 | 760 | 26 | 22 HRC | 2.2 % IACS |
What is 1.4474-AC?
1.4474-AC is 1.4474 heat treated to AC — limit as-cast material to non-pressure, non-corrosive blanks or parts to be re-heat-treated; sigma phase and nitrides leave only 8 % elongation and unacceptable corrosion resistance in service. 1.4474-AC has a yield strength of 470 MPa (68.2 ksi) and a tensile strength of 640 MPa (92.8 ksi) — stronger than 74% of stainless steel grades. Elongation at break is 8% and the elastic modulus is 200 GPa (29 Msi). 1.4474-AC 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). ST is the default condition FabDigit quotes; AC is available on request or by drawing note.
Limitations
- Limited service temperature — 200°C (392 °F), worse than 100% of stainless steel grades
- Limited ductility — 8%, worse than 99% of stainless steel grades
- Limited formability — 8/100, worse than 97% of stainless steel grades
- Low fracture toughness — 45 MPa·√m (41 ksi·√in), worse than 95% of stainless steel grades
- Difficult to machine — 25/100, worse than 88% of stainless steel grades
1.4474-AC properties
Typical room-temperature values for 1.4474-AC; 23 are specific to this condition. Other listed values are 1.4474 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
1.4474-AC 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
1.4474-AC has a yield strength of 470 MPa (68.2 ksi) and a tensile strength of 640 MPa (92.8 ksi) — stronger than 74% of stainless steel grades. Elongation at break is 8% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
1.4474-AC is rated for continuous service to 200°C (392 °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 µm/m·K (6.67 µin/in·°F).
Electrical3
1.4474-AC conducts electricity at 2.1 % IACS, worse than 73% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (50/100), worse than 78% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.4474-AC takes about 55 MJ of energy and emits 4.5 kg of CO₂ — more than 50% of stainless steel grades. Typical recycled content is 75%.
Manufacturability8
1.4474-AC's machinability is poor (25/100, worse than 88% of stainless steel grades); weldability fair (35/100); formability not recommended (8/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.4474-AC
Is 1.4474 easy to machine?
The duplex structure work-hardens quickly and conducts heat poorly: use rigid clamping, positive-rake carbide or coated carbide, low speed with heavy feed, and a depth of cut greater than the hardened layer. Cool generously and avoid recutting the same surface.
Can 1.4474 be welded?
GTAW and SMAW are usable with over-alloyed 25Cr duplex consumables (E2209 / ER2594 types), interpass temperature 150 °C or lower and moderate heat input to hold about 50% ferrite. Do not use nitrogen-free pure argon shielding; re-solution anneal and quench the whole part after repair welds on critical castings.
Can 1.4474 be formed, bent or molded?
Produced by sand or investment casting at a pouring temperature of about 1520-1560 °C with good feeding and nitrogen recovery control. Solution treat at 1040-1120 °C and water quench rapidly after casting to avoid sigma phase; not suitable for cold forming.
What surface finishes work on 1.4474?
Pickle (HNO₃/HF) and passivate, or electropolish, to build a complete passive film, and remove residual iron contamination from blasting or machining. Mirror polishing is possible but the two phases polish at different rates; anodizing does not apply.
1.4474 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 grade; low carbon suppresses carbide formation | ≤ 0.06 | 0.04 |
| Si | ≤ 1 | 0.7 |
| Mn | ≤ 1 | 0.7 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.03 | 0.01 |
| Cr | 25 – 27 | 26 |
| Ni | 4.5 – 6.5 | 5.5 |
| Mo | 1.5 – 2.5 | 2 |
| Nstabilizes austenite and improves pitting resistance | 0.12 – 0.22 | 0.17 |
| Cucopper-free grade; Cu residual (CD4MCu is 2.75-3.25%) | ≤ 0.3 | 0.1 |
| Fe | balance | — |
1.4474-AC — frequently asked
What is 1.4474-AC used for?
1.4474-AC is typically used for pump casings, valve bodies and chemical process equipment. In short: copper-free CD4MCu alternative; 26Cr cast duplex; lower ductility than 4A.
What is the yield strength of 1.4474-AC?
1.4474-AC has a typical yield strength of 470 MPa (68.2 ksi) and a tensile strength of 640 MPa (92.8 ksi) — stronger than 74% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is 1.4474-AC easy to machine?
Not especially — machinability is rated poor (25/100, worse than 88% of stainless steel grades). The duplex structure work-hardens quickly and conducts heat poorly: use rigid clamping, positive-rake carbide or coated carbide, low speed with heavy feed, and a depth of cut greater than the hardened layer. Cool generously and avoid recutting the same surface.
Can 1.4474-AC be welded?
With care — weldability is rated fair (35/100). GTAW and SMAW are usable with over-alloyed 25Cr duplex consumables (E2209 / ER2594 types), interpass temperature 150 °C or lower and moderate heat input to hold about 50% ferrite. Do not use nitrogen-free pure argon shielding; re-solution anneal and quench the whole part after repair welds on critical castings.
What surface finishes work on 1.4474-AC?
Pickle (HNO₃/HF) and passivate, or electropolish, to build a complete passive film, and remove residual iron contamination from blasting or machining. Mirror polishing is possible but the two phases polish at different rates; anodizing does not apply.
Can 1.4474-AC be formed, bent or molded?
Produced by sand or investment casting at a pouring temperature of about 1520-1560 °C with good feeding and nitrogen recovery control. Solution treat at 1040-1120 °C and water quench rapidly after casting to avoid sigma phase; not suitable for cold forming.
What is the maximum service temperature of 1.4474-AC?
1.4474-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 1.4474-ST and 1.4474-AC?
ST is the default condition — use the standard delivery state, solution annealed at 1040–1120 °C and water quenched, as the only treatment that guarantees the duplex phase balance, 520 MPa yield and corrosion resistance. AC: limit as-cast material to non-pressure, non-corrosive blanks or parts to be re-heat-treated; sigma phase and nitrides leave only 8 % elongation and unacceptable corrosion resistance in service. Yield strength is 520 MPa in ST versus 470 MPa in AC.
Sources
- EN 10283 — Corrosion resistant steel castings — CEN (2010)
- ASTM A890/A890M — Castings, Iron-Chromium-Nickel-Molybdenum Corrosion-Resistant, Duplex (Grade 1A / CD4MCu) — ASTM International (2018)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (cast corrosion-resistant alloys) — ASM International (1990)
- Practical Guidelines for the Fabrication of Duplex Stainless Steels (IMOA) — International Molybdenum Association (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.