Stainless Steel 1.4729-AC (Spheroidize annealed)
Heat-treated state
EN 1.4729
Cheapest condition for non-critical furnace and exhaust hardware where hardness and low ductility are acceptable.
Values for the AC condition
Other 1.4729 tempers and conditions
1.4729 is listed in 4 conditions; see the grade overview at 1.4729.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ADefault Solution annealed | Standard delivery condition per EN 10295: lowest hardness (≤300 HB) for machining before service at high temperature. | 420 | 680 | 10 | 21 HRC | — |
Stress relieved | Use after welding or heavy machining of complex castings to limit distortion and residual stress without full softening. | 440 | 700 | 8 | 23 HRC | 2.5 % IACS |
ACThis page Spheroidize annealed | Cheapest condition for non-critical furnace and exhaust hardware where hardness and low ductility are acceptable. | 460 | 720 | 5 | 27 HRC | 2.5 % IACS |
Quenched and tempered | Choose when wear resistance and strength are needed at moderate temperature, e.g. valve seats and guides; toughness stays low. | 750 | 1,000 | 4 | 38 HRC | — |
What is 1.4729-AC?
1.4729-AC is 1.4729 heat treated to AC — cheapest condition for non-critical furnace and exhaust hardware where hardness and low ductility are acceptable. 1.4729-AC has a yield strength of 460 MPa (66.7 ksi) and a tensile strength of 720 MPa (104 ksi) — stronger than 73% of stainless steel grades. Elongation at break is 5% and the elastic modulus is 215 GPa (31.2 Msi). 1.4729-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). A is the default condition FabDigit quotes; AC is available on request or by drawing note.
Advantages
- Low embodied carbon — 3.4 kg CO₂/kg, better than 91% of stainless steel grades
- Conducts heat well — 24 W/m·K (13.9 BTU/hr·ft·°F), better than 81% of stainless steel grades
- High service temperature — 850°C (1,562 °F), better than 80% of stainless steel grades
Limitations
- Limited ductility — 5%, worse than 100% of stainless steel grades
- Low fracture toughness — 25 MPa·√m (22.8 ksi·√in), worse than 99% of stainless steel grades
- Limited formability — 5/100, worse than 99% of stainless steel grades
- Difficult to weld — 18/100, worse than 97% of stainless steel grades
- Needs corrosion protection — 42/100, worse than 90% of stainless steel grades
1.4729-AC properties
Typical room-temperature values for 1.4729-AC; 22 are specific to this condition. Other listed values are 1.4729 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
1.4729-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
1.4729-AC has a yield strength of 460 MPa (66.7 ksi) and a tensile strength of 720 MPa (104 ksi) — stronger than 73% of stainless steel grades. Elongation at break is 5% and the elastic modulus is 215 GPa (31.2 Msi).
Thermal6
1.4729-AC is rated for continuous service to 850°C (1,562 °F). It conducts heat at 24 W/m·K (13.9 BTU/hr·ft·°F), better than 81% of stainless steel grades. Thermal expansion is 10.5 µm/m·K (5.83 µin/in·°F).
Electrical3
1.4729-AC conducts electricity at 2.5 % IACS, better than 75% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (42/100), worse than 90% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.4729-AC takes about 45 MJ of energy and emits 3.4 kg of CO₂ — less than 91% of stainless steel grades. Typical recycled content is 70%.
Manufacturability8
1.4729-AC's machinability is poor (28/100, worse than 79% of stainless steel grades); weldability poor (18/100); formability not recommended (5/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.4729-AC
Is 1.4729 easy to machine?
Machine in the soft annealed state with sharp carbide tooling, rigid setups, low speeds and generous coolant; abrasive Cr carbides and high Si cause rapid flank wear.
Can 1.4729 be welded?
Air-hardening 0.4 %C 13Cr — preheat 250–350 °C, use matching or 309/Ni-base filler, keep interpass temperature and follow immediately with 700–750 °C tempering to avoid cracking.
Can 1.4729 be formed, bent or molded?
Supplied as sand or investment castings; not cold formable — control section thickness and feeding to avoid shrinkage porosity and hot tearing.
What surface finishes work on 1.4729?
Shot blast and pickle/passivate scale after heat treatment; can be ground and lightly polished, but for long-term >850 °C service consider aluminide or ceramic coatings rather than plating.
1.4729 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 | 0.3 – 0.5 | 0.4 |
| Sihigh Si for oxidation resistance | 1 – 2.5 | 1.8 |
| Mn | ≤ 1 | 0.6 |
| Cr | 12 – 14 | 13 |
| Niresidual | ≤ 1 | 0.3 |
| Pimpurity | ≤ 0.04 | — |
| Simpurity | ≤ 0.03 | — |
| Fe | balance | — |
1.4729-AC — frequently asked
What is 1.4729-AC used for?
1.4729-AC is typically used for exhaust valve seats, turbocharger parts, heat-resistant fittings and furnace components. In short: harder 13Cr-Si casting grade; heat treatable to 21 HRC; 850 °C oxidation resistance.
What is the yield strength of 1.4729-AC?
1.4729-AC has a typical yield strength of 460 MPa (66.7 ksi) and a tensile strength of 720 MPa (104 ksi) — stronger than 73% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is 1.4729-AC easy to machine?
Not especially — machinability is rated poor (28/100, worse than 79% of stainless steel grades). Machine in the soft annealed state with sharp carbide tooling, rigid setups, low speeds and generous coolant; abrasive Cr carbides and high Si cause rapid flank wear.
Can 1.4729-AC be welded?
Not readily — weldability is rated poor (18/100). Air-hardening 0.4 %C 13Cr — preheat 250–350 °C, use matching or 309/Ni-base filler, keep interpass temperature and follow immediately with 700–750 °C tempering to avoid cracking.
What surface finishes work on 1.4729-AC?
Shot blast and pickle/passivate scale after heat treatment; can be ground and lightly polished, but for long-term >850 °C service consider aluminide or ceramic coatings rather than plating.
Can 1.4729-AC be formed, bent or molded?
Supplied as sand or investment castings; not cold formable — control section thickness and feeding to avoid shrinkage porosity and hot tearing.
What is the maximum service temperature of 1.4729-AC?
1.4729-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 1.4729-A and 1.4729-QT?
A is the default condition — standard delivery condition per EN 10295: lowest hardness (≤300 HB) for machining before service at high temperature. QT: choose when wear resistance and strength are needed at moderate temperature, e.g. valve seats and guides; toughness stays low. Yield strength is 420 MPa in A versus 750 MPa in QT.
Sources
- EN 10295 — Heat resistant steel castings — CEN (2002)
- EN 10027-2 — Material number 1.4729 designation system — CEN (2015)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.15 — Casting — ASM International (2008)
- Heat-resistant cast stainless steel grade datasheets (GX40CrSi13) — European steel 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.