Stainless Steel 1.4405-AC (Spheroidize annealed)
Heat-treated state
EN 1.4405
Raw casting with untempered martensite; only an intermediate state for shipping to heat treatment, never for service.
Values for the AC condition
Other 1.4405 tempers and conditions
1.4405 is listed in 6 conditions; see the grade overview at 1.4405.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Choose when the casting must be rough-machined or heavily welded before final quench-and-temper. | 480 | 720 | 20 | 21 HRC | 2.2 % IACS |
+QT760 double tempered | Pick for sub-zero / offshore duty or thick sections where retained-austenite conditioning and full temper of fresh martensite are required. | 600 | 820 | 20 | 27 HRC | 2.2 % IACS |
QT760Default austenitized ~1000–1050 °C, quenched, tempered ~580–620 °C | Standard EN 10283 delivery condition; the balanced strength/toughness state for pumps, valves and hydraulic turbine parts. | 620 | 850 | 18 | 29 HRC | — |
HIP + quenched and tempered | Specify for thick-wall pressure-containing or fatigue-critical castings where internal porosity must be closed. | 640 | 880 | 20 | 29 HRC | 2.2 % IACS |
ACThis page Spheroidize annealed | Raw casting with untempered martensite; only an intermediate state for shipping to heat treatment, never for service. | 750 | 1,000 | 6 | 40 HRC | 2.1 % IACS |
lower tempering temperature (~520–560 °C) for higher strength | Order when higher yield/wear capability is needed and impact requirements are moderate (runner hubs, high-head hydraulic parts). | 800 | 980 | 12 | 34 HRC | 2.2 % IACS |
What is 1.4405-AC?
1.4405-AC is 1.4405 heat treated to AC — raw casting with untempered martensite; only an intermediate state for shipping to heat treatment, never for service. 1.4405-AC has a yield strength of 750 MPa (109 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 93% of stainless steel grades. Elongation at break is 6% and the elastic modulus is 200 GPa (29 Msi). 1.4405-AC 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). QT760 is the default condition FabDigit quotes; AC is available on request or by drawing note.
Advantages
- High strength — 750 MPa (109 ksi), better than 93% of stainless steel grades
- Low embodied carbon — 3.6 kg CO₂/kg, better than 83% of stainless steel grades
- Conducts heat well — 23 W/m·K (13.3 BTU/hr·ft·°F), better than 78% of stainless steel grades
Limitations
- Limited formability — 3/100, worse than 100% of stainless steel grades
- Limited ductility — 6%, worse than 99% of stainless steel grades
- Limited service temperature — 250°C (482 °F), worse than 99% of stainless steel grades
- Difficult to machine — 20/100, worse than 98% of stainless steel grades
- Low fracture toughness — 50 MPa·√m (45.5 ksi·√in), worse than 92% of stainless steel grades
1.4405-AC properties
Typical room-temperature values for 1.4405-AC; 22 are specific to this condition. Other listed values are 1.4405 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
1.4405-AC 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).
Mechanical16
1.4405-AC has a yield strength of 750 MPa (109 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 93% of stainless steel grades. Elongation at break is 6% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
1.4405-AC is rated for continuous service to 250°C (482 °F). It conducts heat at 23 W/m·K (13.3 BTU/hr·ft·°F), better than 78% of stainless steel grades. Thermal expansion is 10.5 µm/m·K (5.83 µin/in·°F).
Electrical3
1.4405-AC conducts electricity at 2.1 % IACS, worse than 73% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (45/100), worse than 85% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.4405-AC takes about 53 MJ of energy and emits 3.6 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 70%.
Manufacturability8
1.4405-AC's machinability is poor (20/100, worse than 98% of stainless steel grades); weldability fair (35/100); formability not recommended (3/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.4405-AC
Is 1.4405 easy to machine?
Machine in the tempered condition with rigid setups, sharp coated carbide, low speed / high feed and generous coolant; work-hardening skin and cast surface scale demand a heavy first cut.
Can 1.4405 be welded?
Readily weldable with matching 16-5-1 or 410NiMo filler; preheat 100–150 °C, keep interpass below ~180 °C and re-temper at 580–600 °C after major repairs.
Can 1.4405 be formed, bent or molded?
Sand or investment cast with generous feeding and chills; solidification shrinkage ~4–5 %, so risering and directional solidification control soundness.
What surface finishes work on 1.4405?
Passivate or pickle after machining/welding to restore the chromium oxide film; electropolishing improves cleanability, no anodizing — paint or thermal spray only where erosion is severe.
1.4405 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 for soft martensite and weldability | ≤ 0.06 | 0.04 |
| Si | ≤ 0.8 | 0.5 |
| Mn | ≤ 1 | 0.7 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.03 | 0.01 |
| Cr | 15 – 17 | 16 |
| Ni | 4 – 6 | 5 |
| Mopitting/cavitation resistance | 0.7 – 1.5 | 1 |
| Fe | balance | — |
1.4405-AC — frequently asked
What is 1.4405-AC used for?
1.4405-AC is typically used for high-head hydraulic turbine components, marine and offshore castings and pump casings in aggressive media. In short: corrosion-upgraded soft martensitic; hardest in family, 285 HB; marine and hydraulic castings.
What is the yield strength of 1.4405-AC?
1.4405-AC has a typical yield strength of 750 MPa (109 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 93% of stainless steel grades. Strength varies by condition: see the 6 listed tempers.
Is 1.4405-AC easy to machine?
Not especially — machinability is rated poor (20/100, worse than 98% of stainless steel grades). Machine in the tempered condition with rigid setups, sharp coated carbide, low speed / high feed and generous coolant; work-hardening skin and cast surface scale demand a heavy first cut.
Can 1.4405-AC be welded?
With care — weldability is rated fair (35/100). Readily weldable with matching 16-5-1 or 410NiMo filler; preheat 100–150 °C, keep interpass below ~180 °C and re-temper at 580–600 °C after major repairs.
What surface finishes work on 1.4405-AC?
Passivate or pickle after machining/welding to restore the chromium oxide film; electropolishing improves cleanability, no anodizing — paint or thermal spray only where erosion is severe.
Can 1.4405-AC be formed, bent or molded?
Sand or investment cast with generous feeding and chills; solidification shrinkage ~4–5 %, so risering and directional solidification control soundness.
What is the maximum service temperature of 1.4405-AC?
1.4405-AC is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 1.4405-QT760 and 1.4405-QT900?
QT760 is the default condition — standard EN 10283 delivery condition; the balanced strength/toughness state for pumps, valves and hydraulic turbine parts. QT900: order when higher yield/wear capability is needed and impact requirements are moderate (runner hubs, high-head hydraulic parts). Yield strength is 620 MPa in QT760 versus 800 MPa in QT900.
Sources
- EN 10283 — Corrosion resistant steel castings — CEN (2010)
- ASTM A743/A487 (CA6NM-type soft martensitic cast stainless) — ASTM (2019)
- 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)
- Soft martensitic cast stainless (GX4CrNi13-4 / GX4CrNiMo16-5-1) foundry datasheets — European stainless foundries (2022)
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.