Stainless Steel 1.4451 SA+Q
Heat-treated state · default condition
EN 1.4451
SA+Q = solution annealed ~1080–1120 °C, water quenched
Standard delivery condition for all pressure- and corrosion-service castings; balances ferrite/austenite and dissolves σ-phase and Cr-nitrides.
Values for the SA+Q condition
Other 1.4451 tempers and conditions
1.4451 is listed in 4 conditions; see the grade overview at 1.4451.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Only for non-critical, non-corrosive or rough-machining-stock parts — intermetallics and nitrides in the as-cast structure cut toughness and corrosion resistance sharply. | 480 | 660 | 10 | 26 HRC | 2.1 % IACS |
SA+QDefaultThis page Solution annealed ~1080–1120 °C, water quenched | Standard delivery condition for all pressure- and corrosion-service castings; balances ferrite/austenite and dissolves σ-phase and Cr-nitrides. | 510 | 700 | 22 | 23 HRC | 2.2 % IACS |
Hot isostatically pressed, then solution annealed and quenched | Choose for thick-wall pumps/valves needing closed micro-shrinkage, better ductility and toughness and radiographic soundness. | 530 | 730 | 27 | 24 HRC | 2.2 % IACS |
Centrifugally cast tube/ring, solution annealed and quenched | Pick for cylinder liners, seal rings and pipe spools where the denser, finer centrifugal structure raises strength and soundness. | 540 | 740 | 24 | 24 HRC | 2.2 % IACS |
What is 1.4451 SA+Q?
1.4451 SA+Q is 1.4451 heat treated to SA+Q — standard delivery condition for all pressure- and corrosion-service castings; balances ferrite/austenite and dissolves σ-phase and Cr-nitrides. 1.4451 SA+Q has a yield strength of 510 MPa (74 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 78% of stainless steel grades. Elongation at break is 22% and the elastic modulus is 200 GPa (29 Msi). 1.4451 SA+Q has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Advantages
- Good corrosion resistance — 82/100, better than 90% of stainless steel grades
- High strength — 510 MPa (74 ksi), better than 78% of stainless steel grades
Limitations
- Limited service temperature — 280°C (536 °F), worse than 96% of stainless steel grades
- Low fracture toughness — 80 MPa·√m (72.8 ksi·√in), worse than 79% of stainless steel grades
- Limited formability — 25/100, worse than 78% of stainless steel grades
- Limited ductility — 22%, worse than 75% of stainless steel grades
1.4451 SA+Q properties
Typical room-temperature values for 1.4451 SA+Q; 24 are specific to this condition. Other listed values are 1.4451 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
1.4451 SA+Q has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical17
1.4451 SA+Q has a yield strength of 510 MPa (74 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 78% of stainless steel grades. Elongation at break is 22% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
1.4451 SA+Q 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 12.5 µm/m·K (6.94 µin/in·°F).
Electrical3
1.4451 SA+Q conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is very good (82/100), better than 90% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.4451 SA+Q takes about 55 MJ of energy and emits 4.6 kg of CO₂ — more than 50% of stainless steel grades. Typical recycled content is 75%.
Manufacturability7
1.4451 SA+Q's machinability is poor (30/100, worse than 70% 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 1.4451 SA+Q
Is 1.4451 easy to machine?
Work-hardens and runs hot: use rigid setups, sharp coated carbide, low speed / high positive feed, generous flood coolant and avoid dwelling.
Can 1.4451 be welded?
Weldable with matching 25Cr super-duplex or 25-9-4 filler; keep interpass below ~150 °C, control heat input for a balanced ferrite/austenite weld, and re-solution-anneal heavily repaired castings.
Can 1.4451 be formed, bent or molded?
Supplied as sand or centrifugal castings — design generous fillets and directional feeding for the wide freezing range; cold forming is not applicable.
What surface finishes work on 1.4451?
Pickle and passivate after grinding or welding to restore the passive film; takes a good mechanical polish but no anodizing.
1.4451 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 grade | ≤ 0.03 | 0.02 |
| Si | ≤ 1 | 0.6 |
| Mn | ≤ 1.5 | 0.8 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.03 | 0.01 |
| Cr | 25 – 27 | 26 |
| Ni | 4.5 – 6 | 5.2 |
| Mo | 2.5 – 3.5 | 3 |
| Cuimproves resistance in sulfuric acid | 2.5 – 3.5 | 3 |
| Naustenite stabiliser, raises PREN | 0.12 – 0.25 | 0.18 |
| Fe | balance | — |
1.4451 SA+Q — frequently asked
What is 1.4451 SA+Q used for?
1.4451 SA+Q is typically used for seawater valve bodies, flue-gas desulfurization castings and chemical pumps. In short: highest-strength cast stainless here; chloride and sulfuric acid service; duplex-leaning cast structure.
What is the yield strength of 1.4451 SA+Q?
1.4451 SA+Q has a typical yield strength of 510 MPa (74 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 78% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is 1.4451 SA+Q easy to machine?
Not especially — machinability is rated poor (30/100, worse than 70% of stainless steel grades). Work-hardens and runs hot: use rigid setups, sharp coated carbide, low speed / high positive feed, generous flood coolant and avoid dwelling.
Can 1.4451 SA+Q be welded?
Yes — weldability is rated good (55/100). Weldable with matching 25Cr super-duplex or 25-9-4 filler; keep interpass below ~150 °C, control heat input for a balanced ferrite/austenite weld, and re-solution-anneal heavily repaired castings.
What surface finishes work on 1.4451 SA+Q?
Pickle and passivate after grinding or welding to restore the passive film; takes a good mechanical polish but no anodizing.
Can 1.4451 SA+Q be formed, bent or molded?
Supplied as sand or centrifugal castings — design generous fillets and directional feeding for the wide freezing range; cold forming is not applicable.
What is the maximum service temperature of 1.4451 SA+Q?
1.4451 SA+Q 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 1.4451 SA+Q and 1.4451-AC?
SA+Q is the default condition — standard delivery condition for all pressure- and corrosion-service castings; balances ferrite/austenite and dissolves σ-phase and Cr-nitrides. AC: only for non-critical, non-corrosive or rough-machining-stock parts — intermetallics and nitrides in the as-cast structure cut toughness and corrosion resistance sharply. Yield strength is 510 MPa in SA+Q versus 480 MPa in AC.
Sources
- EN 10283 — Corrosion resistant steel castings — CEN (2010)
- ASTM A890/A890M — Castings, Iron-Chromium-Nickel-Molybdenum Corrosion-Resistant, Duplex (Grade 1B / CD4MCuN) — ASTM (2018)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Steel Castings Handbook — Steel Founders' Society of America / ASM (1995)
- Cast super duplex (CD4MCuN / 1.4517 class) pump and valve casting datasheets — various foundries (2023)
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.