Stainless Steel 1.4710-AC (Spheroidize annealed)
Heat-treated state
EN 1.4710
Cheapest route for exhaust/turbo parts where strength matters more than machining and ductility; structure is partly air-hardened.
Values for the AC condition
Other 1.4710 tempers and conditions
1.4710 is listed in 3 conditions; see the grade overview at 1.4710.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ADefault Solution annealed | Standard supply condition: softens the air-hardened matrix for machining and gives the mechanical values quoted in EN 10295. | 290 | 520 | 6 | 205 HB | — |
Stress relieved | Used on complex thin-wall manifolds/turbine housings to remove casting and welding stresses without fully softening the part. | 330 | 570 | 4 | 20 HRC | 2.4 % IACS |
ACThis page Spheroidize annealed | Cheapest route for exhaust/turbo parts where strength matters more than machining and ductility; structure is partly air-hardened. | 400 | 640 | 2 | 26 HRC | 2.4 % IACS |
What is 1.4710-AC?
1.4710-AC is 1.4710 heat treated to AC — cheapest route for exhaust/turbo parts where strength matters more than machining and ductility; structure is partly air-hardened. 1.4710-AC has a yield strength of 400 MPa (58 ksi) and a tensile strength of 640 MPa (92.8 ksi) — stronger than 57% of stainless steel grades. Elongation at break is 2% and the elastic modulus is 205 GPa (29.7 Msi). 1.4710-AC has a density of 7.65 g/cm³ (0.276 lb/in³), lighter than 96% of stainless steel grades. It melts at 1,400°C (2,552 °F). A is the default condition FabDigit quotes; AC is available on request or by drawing note.
Advantages
- Low embodied carbon — 2.6 kg CO₂/kg, better than 100% of stainless steel grades
- Conducts heat well — 26 W/m·K (15 BTU/hr·ft·°F), better than 96% of stainless steel grades
- High service temperature — 850°C (1,562 °F), better than 80% of stainless steel grades
Limitations
- Limited ductility — 2%, worse than 100% of stainless steel grades
- Needs corrosion protection — 28/100, worse than 100% of stainless steel grades
- Limited formability — 3/100, worse than 100% of stainless steel grades
- Hard to polish — 40/100, worse than 99% of stainless steel grades
- Difficult to weld — 22/100, worse than 94% of stainless steel grades
1.4710-AC properties
Typical room-temperature values for 1.4710-AC; 22 are specific to this condition. Other listed values are 1.4710 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
1.4710-AC has a density of 7.65 g/cm³ (0.276 lb/in³), lighter than 96% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical14
1.4710-AC has a yield strength of 400 MPa (58 ksi) and a tensile strength of 640 MPa (92.8 ksi) — stronger than 57% of stainless steel grades. Elongation at break is 2% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
1.4710-AC is rated for continuous service to 850°C (1,562 °F). It conducts heat at 26 W/m·K (15 BTU/hr·ft·°F), better than 96% of stainless steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical2
1.4710-AC has an electrical resistivity of 7.2×10⁻⁷ Ω·m.
Chemical & Environmental2
Corrosion resistance is poor (28/100), worse than 100% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.4710-AC takes about 34 MJ of energy and emits 2.6 kg of CO₂ — less than 100% of stainless steel grades. Typical recycled content is 80%.
Manufacturability8
1.4710-AC's machinability is poor (25/100, worse than 88% of stainless steel grades); weldability poor (22/100); formability not recommended (3/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.4710-AC
Is 1.4710 easy to machine?
Machine in the annealed condition with rigid setups, carbide inserts and moderate speeds; Cr carbides and cast skin are abrasive and work-harden the surface.
Can 1.4710 be welded?
Weldable for repair with matching Cr-Si or austenitic (309/312) filler; preheat 200–300 °C, hold interpass temperature and stress relieve/anneal after welding to avoid hard-zone cracking.
Can 1.4710 be formed, bent or molded?
Supplied only as sand or shell castings — good fluidity from the high silicon allows thin-wall manifolds; no cold forming, keep sections uniform to limit hot tearing.
What surface finishes work on 1.4710?
Shot blast the oxide skin; protect wet-service faces with high-temperature aluminium/silicone paint, aluminising or ceramic coating since the 7% Cr level will not prevent rusting.
1.4710 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 |
|---|---|---|
| C | 0.2 – 0.35 | 0.3 |
| Sikey for scaling resistance | 1 – 2.5 | 1.7 |
| Mn | ≤ 1 | 0.6 |
| P | ≤ 0.04 | — |
| S | ≤ 0.03 | — |
| Cr | 6 – 8 | 7 |
| Niresidual | ≤ 0.5 | — |
| Fe | balance | — |
1.4710-AC — frequently asked
What is 1.4710-AC used for?
1.4710-AC is typically used for exhaust manifolds, turbocharger housings and moderate-temperature exhaust components. In short: low-cost exhaust casting grade; 850 °C scaling limit; thin-wall casting fluidity.
What is the yield strength of 1.4710-AC?
1.4710-AC has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 640 MPa (92.8 ksi) — stronger than 57% of stainless steel grades. Strength varies by condition: see the 3 listed tempers.
Is 1.4710-AC easy to machine?
Not especially — machinability is rated poor (25/100, worse than 88% of stainless steel grades). Machine in the annealed condition with rigid setups, carbide inserts and moderate speeds; Cr carbides and cast skin are abrasive and work-harden the surface.
Can 1.4710-AC be welded?
Not readily — weldability is rated poor (22/100). Weldable for repair with matching Cr-Si or austenitic (309/312) filler; preheat 200–300 °C, hold interpass temperature and stress relieve/anneal after welding to avoid hard-zone cracking.
What surface finishes work on 1.4710-AC?
Shot blast the oxide skin; protect wet-service faces with high-temperature aluminium/silicone paint, aluminising or ceramic coating since the 7% Cr level will not prevent rusting.
Can 1.4710-AC be formed, bent or molded?
Supplied only as sand or shell castings — good fluidity from the high silicon allows thin-wall manifolds; no cold forming, keep sections uniform to limit hot tearing.
What is the maximum service temperature of 1.4710-AC?
1.4710-AC is rated for continuous use to about 850°C (1,562 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 1.4710-A and 1.4710-AC?
A is the default condition — standard supply condition: softens the air-hardened matrix for machining and gives the mechanical values quoted in EN 10295. AC: cheapest route for exhaust/turbo parts where strength matters more than machining and ductility; structure is partly air-hardened. Yield strength is 290 MPa in A versus 400 MPa in AC.
Sources
- EN 10295 — Heat resistant steel castings — CEN (2002)
- DIN 17465 (withdrawn) — Heat resisting steel castings — DIN (1990)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- Heat-resistant cast steel grade datasheets (exhaust manifold / turbocharger housing alloys) — European and Chinese 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.