Stainless Steel 1.4474-ST (Solution annealed)
Heat-treated state · default condition
EN 1.4474
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.
Values for the ST 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 |
|---|---|---|---|---|---|---|
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 |
STDefaultThis page 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-ST?
1.4474-ST is 1.4474 heat treated to ST — 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. 1.4474-ST has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 730 MPa (106 ksi) — stronger than 79% of stainless steel grades. Elongation at break is 22% and the elastic modulus is 200 GPa (29 Msi). 1.4474-ST 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 — 520 MPa (75.4 ksi), better than 79% of stainless steel grades
Limitations
- Limited service temperature — 280°C (536 °F), worse than 96% of stainless steel grades
- Limited formability — 15/100, worse than 91% of stainless steel grades
- Limited ductility — 22%, worse than 75% of stainless steel grades
1.4474-ST properties
Typical room-temperature values for 1.4474-ST; 11 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-ST 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-ST has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 730 MPa (106 ksi) — stronger than 79% of stainless steel grades. Elongation at break is 22% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
1.4474-ST is rated for continuous service to 280°C (536 °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-ST conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is very good (70/100), better than 68% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.4474-ST 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-ST's machinability is poor (30/100, worse than 70% of stainless steel grades); weldability good (55/100); formability poor (15/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.4474-ST
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-ST — frequently asked
What is 1.4474-ST used for?
1.4474-ST 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-ST?
1.4474-ST has a typical yield strength of 520 MPa (75.4 ksi) and a tensile strength of 730 MPa (106 ksi) — stronger than 79% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is 1.4474-ST easy to machine?
Not especially — machinability is rated poor (30/100, worse than 70% 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-ST be welded?
Yes — weldability is rated good (55/100). 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-ST?
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-ST 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-ST?
1.4474-ST is rated for continuous use to about 280°C (536 °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.