Steel A732 15A
Heat-treated state
ASTM A732
15A = grade 15A
Annealed alloy chemistry supplied soft for extensive machining and subsequent customer heat treatment.
Values for the 15A condition
Other A732 tempers and conditions
A732 is listed in 17 conditions; see the grade overview at A732.
Compare all 17 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Grade 1A | Softest, most weldable grade — general non-critical structural investment castings. | 250 | 460 | 24 | 130 HB | — |
Grade 2A | Medium-carbon annealed casting where machining ease outweighs strength. | 275 | 500 | 22 | 145 HB | — |
Grade 4A | Highest-strength annealed grade; used where parts are machined then case-hardened. | 330 | 600 | 16 | 174 HB | — |
Grade 5N | Normalized alloy grade with uniform structure in thicker sections and good toughness. | 430 | 610 | 18 | 179 HB | — |
15AThis page Grade 15A | Annealed alloy chemistry supplied soft for extensive machining and subsequent customer heat treatment. | 430 | 640 | 18 | 187 HB | — |
Grade 2Q | Entry-level Q&T carbon casting for moderately loaded parts. | 460 | 640 | 18 | 190 HB | — |
Grade 6N | Normalized alloy grade when Q&T distortion is unacceptable but ~650 MPa is needed. | 470 | 680 | 15 | 14 HRC | — |
Grade 3Q | Q&T medium-carbon casting balancing strength and cost. | 510 | 710 | 16 | 16 HRC | — |
Grade 7Q | First of the alloy Q&T ladder; ~690 MPa class with good ductility. | 540 | 715 | 15 | 17 HRC | — |
Grade 4Q | Q&T grade for shafts, levers and linkage castings needing ~720 MPa class strength. | 580 | 750 | 14 | 20 HRC | — |
8QDefault Grade 8Q | Most commonly ordered general-purpose Q&T alloy investment casting (~725 MPa class). | 605 | 745 | 14 | 18 HRC | — |
Grade 9Q | ~790 MPa class Q&T casting for loaded brackets, yokes and hydraulic bodies. | 675 | 815 | 12 | 23 HRC | — |
Grade 10Q | ~860 MPa class; used where higher hardness and wear life are required. | 745 | 885 | 11 | 26 HRC | — |
Grade 11Q | ~930 MPa class high-strength casting for compact, highly loaded components. | 815 | 955 | 10 | 30 HRC | — |
Grade 12Q | ~1000 MPa class; select when strength-to-weight matters more than toughness. | 890 | 1,035 | 9 | 33 HRC | — |
Grade 13Q | ~1070 MPa class near the practical toughness limit of cast low-alloy steel. | 960 | 1,105 | 8 | 36 HRC | — |
Grade 14Q | Top of the A732 strength ladder (~1200 MPa) for small, highly stressed precision castings. | 1,035 | 1,240 | 7 | 39 HRC | — |
What is A732 15A?
A732 15A is A732 heat treated to 15A — annealed alloy chemistry supplied soft for extensive machining and subsequent customer heat treatment. A732 15A has a yield strength of 430 MPa (62.4 ksi) and a tensile strength of 640 MPa (92.8 ksi) — weaker than 51% of steel grades. Elongation at break is 18% and the elastic modulus is 205 GPa (29.7 Msi). A732 15A has a density of 7.83 g/cm³ (0.283 lb/in³), lighter than 80% of steel grades. It melts at 1,425°C (2,597 °F). 8Q is the default condition FabDigit quotes; 15A is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 68/100, better than 83% of steel grades
Limitations
- Limited formability — 10/100, worse than 95% of steel grades
A732 15A properties
Typical room-temperature values for A732 15A; 12 are specific to this condition. Other listed values are A732 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
A732 15A has a density of 7.83 g/cm³ (0.283 lb/in³), lighter than 80% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
A732 15A has a yield strength of 430 MPa (62.4 ksi) and a tensile strength of 640 MPa (92.8 ksi) — weaker than 51% of steel grades. Elongation at break is 18% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
A732 15A is rated for continuous service to 425°C (797 °F). It conducts heat at 42 W/m·K (24.3 BTU/hr·ft·°F), worse than 56% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
A732 15A conducts electricity at 8.6 % IACS, better than 66% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of A732 15A takes about 26 MJ of energy and emits 2 kg of CO₂ — less than 64% of steel grades. Typical recycled content is 75%.
Manufacturability7
A732 15A's machinability is good (57/100, better than 71% of steel grades); weldability good (60/100); formability not recommended (10/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with A732 15A
Is A732 easy to machine?
Machines like wrought 1040/8630 at the same hardness; keep Q&T grades below ~300 HB for economical milling and use rigid setups on thin cast sections.
Can A732 be welded?
Carbon and normalized grades weld readily with low-hydrogen consumables; Q&T grades above ~9Q need 150–250 °C preheat and post-weld tempering below the original tempering temperature.
Can A732 be formed, bent or molded?
Lost-wax shell process gives ±0.13 mm per 25 mm tolerance and Ra ~3.2 µm; design 1.5–2 mm minimum wall, generous fillets and uniform sections to avoid hot tears and shrinkage porosity.
What surface finishes work on A732?
As-cast surfaces accept shot blast, phosphate, paint, zinc or electroless nickel; polishing to a mirror finish requires grinding out shell texture first — no anodizing (ferrous).
A732 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 |
|---|---|---|
| Cgrade-dependent; low for 1A/2A, high for 4A/13Q/14Q | 0.1 – 0.55 | 0.3 |
| Mngrade-dependent | 0.3 – 1.5 | 0.8 |
| Siinvestment casting silica pickup typical | 0.2 – 1 | 0.5 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.05 | 0.02 |
| Cralloy grades (7Q–15A) only | 0 – 1.5 | 0.55 |
| Nialloy grades only | 0 – 2.5 | 0.6 |
| Moalloy grades only | 0 – 0.6 | 0.22 |
| Curesidual max | ≤ 0.5 | 0.15 |
| Voptional/residual | ≤ 0.1 | — |
| Fe | balance | — |
A732 15A — frequently asked
What is A732 15A used for?
A732 15A is typically used for aerospace fittings, valve components, small precision structural parts and firearm components. In short: precision investment cast steel; tightest as-cast tolerances; small-part alternative to A148.
What is the yield strength of A732 15A?
A732 15A has a typical yield strength of 430 MPa (62.4 ksi) and a tensile strength of 640 MPa (92.8 ksi) — weaker than 51% of steel grades. Strength varies by condition: see the 17 listed tempers.
Is A732 15A easy to machine?
Reasonably — machinability is rated good (57/100, better than 71% of steel grades). Machines like wrought 1040/8630 at the same hardness; keep Q&T grades below ~300 HB for economical milling and use rigid setups on thin cast sections.
Can A732 15A be welded?
Yes — weldability is rated good (60/100). Carbon and normalized grades weld readily with low-hydrogen consumables; Q&T grades above ~9Q need 150–250 °C preheat and post-weld tempering below the original tempering temperature.
What surface finishes work on A732 15A?
As-cast surfaces accept shot blast, phosphate, paint, zinc or electroless nickel; polishing to a mirror finish requires grinding out shell texture first — no anodizing (ferrous).
Can A732 15A be formed, bent or molded?
Lost-wax shell process gives ±0.13 mm per 25 mm tolerance and Ra ~3.2 µm; design 1.5–2 mm minimum wall, generous fillets and uniform sections to avoid hot tears and shrinkage porosity.
What is the maximum service temperature of A732 15A?
A732 15A is rated for continuous use to about 425°C (797 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between A732 8Q and A732 14Q?
8Q is the default condition — most commonly ordered general-purpose Q&T alloy investment casting (~725 MPa class). 14Q: top of the A732 strength ladder (~1200 MPa) for small, highly stressed precision castings. Yield strength is 605 MPa in 8Q versus 1,035 MPa in 14Q.
Sources
- ASTM A732/A732M — Castings, Investment, Carbon and Low Alloy Steel for General Application, and Cobalt Alloy for High Strength at Elevated Temperatures — ASTM International (2019)
- Steel Castings Handbook, 6th ed. — Steel Founders' Society of America / ASM (1995)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.15 — Casting — ASM International (2008)
- Cast low-alloy steel property tables (typical mechanical/physical data) — MatWeb / SFSA data compilations (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.