Steel A356 Grade 5
ASTM A356 Grade 5 · UNS J12540
ASTM A356 Grade 5 (UNS J12540) is a 1-1/4Cr-1/2Mo low-alloy steel casting used for pressure-containing parts in high-temperature steam service.
Reference datasheet — A356 Grade 5 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the N+T condition
A356 Grade 5 tempers and conditions
A356 Grade 5 is supplied in 4 conditions, soft to hard. N+T is the default FabDigit quotes; the values on this page are for it.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Softest condition, used for rough machining or repair welding before final normalize-and-temper. | 290 | 490 | 28 | 145 HB | 8 % IACS |
N+T + simulated post-weld heat treatment | Test condition for castings that will see long or repeated PWHT cycles at 690–730 °C; strength drops slightly, toughness recovers. | 320 | 520 | 26 | 160 HB | 7.8 % IACS |
N+TDefault Normalized and tempered | Standard supply condition for heavy-walled turbine casings; best balance of creep strength, toughness and dimensional stability. | 345 | 550 | 24 | 10 HRC | 7.8 % IACS |
Quenched and tempered | Choose when higher yield strength and uniform through-thickness properties are needed in thick sections. | 450 | 620 | 21 | 15 HRC | — |
What is A356 Grade 5?
ASTM A356 Grade 5 (UNS J12540) is a 1-1/4Cr-1/2Mo low-alloy steel casting used for pressure-containing parts in high-temperature steam service. It provides creep resistance and elevated-temperature strength to 550 °C, with 345 MPa yield, 550 MPa tensile, 24 % elongation and about 170 HB in the default condition, and is supplied as sand castings in N+T, Q&T, annealed or N+T+SPWHT condition. Welding requires 200–300 °C preheat and 690–730 °C post-weld heat treatment, and the alloy has no inherent corrosion resistance. Grade 6 (2-1/4Cr-1Mo) is the usual step up when higher creep strength is required. A356 Grade 5 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,450°C (2,642 °F). A356 Grade 5 has a yield strength of 345 MPa (50 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 75% of steel grades. Elongation at break is 24% and the elastic modulus is 207 GPa (30 Msi).
What is A356 Grade 5 used for?
- steam turbine casings
- high-temperature valve bodies
- power plant fittings
Advantages
- High service temperature — 550°C (1,022 °F), better than 95% of steel grades
- Tough — resists crack growth — 120 MPa·√m (109.2 ksi·√in), better than 81% of steel grades
Limitations
- Limited formability — 20/100, worse than 80% of steel grades
- Low strength — 345 MPa (50 ksi), worse than 75% of steel grades
A356 Grade 5 properties
Typical room-temperature values for A356 Grade 5-N+T; bars are the position among steel grades.
Physical3
A356 Grade 5 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,450°C (2,642 °F).
Mechanical17
A356 Grade 5 has a yield strength of 345 MPa (50 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 75% of steel grades. Elongation at break is 24% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
A356 Grade 5 is rated for continuous service to 550°C (1,022 °F). It conducts heat at 40 W/m·K (23.1 BTU/hr·ft·°F), worse than 64% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
A356 Grade 5 conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (20/100), better than 87% of steel grades.
Sustainability4
Producing a kilogram of A356 Grade 5 takes about 27 MJ of energy and emits 2.1 kg of CO₂ — less than 59% of steel grades. Typical recycled content is 75%.
Manufacturability8
A356 Grade 5's machinability is fair (52/100, better than 52% of steel grades); weldability good (55/100); formability poor (20/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. A356 Grade 5 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with A356 Grade 5
Is A356 Grade 5 easy to machine?
Machines like a 170 HB alloy steel — use rigid setups, carbide tooling at 80–140 m/min, and expect abrasive cast skin and possible sand inclusions on the first cut.
Can A356 Grade 5 be welded?
Weldable with matched 1.25Cr-0.5Mo (E8018-B2 / ER80S-B2) consumables; 200–300 °C preheat/interpass and 690–730 °C PWHT are mandatory to avoid hydrogen cracking.
Can A356 Grade 5 be formed, bent or molded?
Supplied only as sand castings; heavy sections need generous risering, chills and controlled solidification, followed by full re-austenitizing heat treatment.
A356 Grade 5 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 |
|---|---|---|
| Ccarbon kept low for weldability of heavy sections | ≤ 0.2 | 0.15 |
| Mn | 0.5 – 0.8 | 0.65 |
| Si | ≤ 0.6 | 0.4 |
| Pkept low to limit temper embrittlement | ≤ 0.03 | 0.02 |
| S | ≤ 0.03 | 0.01 |
| Cr | 1 – 1.5 | 1.25 |
| Mo | 0.45 – 0.65 | 0.55 |
| Niresidual | ≤ 0.5 | — |
| Curesidual | ≤ 0.35 | — |
| Fe | balance | — |
What surface finishes work on A356 Grade 5?
Not anodizable; protect with high-temperature aluminum/silicone paint, metallizing or aluminizing, and radiograph/MT-inspect surfaces before coating.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel A356 Grade 5 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- J12540
How much does A356 Grade 5 cost?
A356 Grade 5 is a standard-cost steel ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
A356 Grade 5 — frequently asked
What is A356 Grade 5 used for?
A356 Grade 5 is typically used for steam turbine casings, high-temperature valve bodies and power plant fittings. In short: classic 1.25Cr-0.5Mo casting; creep service to 550 °C; mandatory PWHT after welding.
What is the yield strength of A356 Grade 5?
A356 Grade 5 has a typical yield strength of 345 MPa (50 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 75% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is A356 Grade 5 easy to machine?
Reasonably — machinability is rated fair (52/100, better than 52% of steel grades). Machines like a 170 HB alloy steel — use rigid setups, carbide tooling at 80–140 m/min, and expect abrasive cast skin and possible sand inclusions on the first cut.
Can A356 Grade 5 be welded?
Yes — weldability is rated good (55/100). Weldable with matched 1.25Cr-0.5Mo (E8018-B2 / ER80S-B2) consumables; 200–300 °C preheat/interpass and 690–730 °C PWHT are mandatory to avoid hydrogen cracking.
What surface finishes work on A356 Grade 5?
Not anodizable; protect with high-temperature aluminum/silicone paint, metallizing or aluminizing, and radiograph/MT-inspect surfaces before coating.
Can A356 Grade 5 be formed, bent or molded?
Supplied only as sand castings; heavy sections need generous risering, chills and controlled solidification, followed by full re-austenitizing heat treatment.
What is the maximum service temperature of A356 Grade 5?
A356 Grade 5 is rated for continuous use to about 550°C (1,022 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between A356 Grade 5 N+T and A356 Grade 5-ANN?
N+T is the default condition — standard supply condition for heavy-walled turbine casings; best balance of creep strength, toughness and dimensional stability. ANN: softest condition, used for rough machining or repair welding before final normalize-and-temper. Yield strength is 345 MPa in N+T versus 290 MPa in ANN.
How much does A356 Grade 5 cost?
A356 Grade 5 is a standard-cost steel ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM A356/A356M — Steel Castings, Carbon, Low Alloy, and Stainless Steel, Heavy-Walled for Steam Turbines — ASTM International (2021)
- ASME BPVC Section II Part D — Material Properties (1-1/4Cr-1/2Mo) — ASME (2023)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol. 13A — Corrosion: Fundamentals, Testing, and Protection — ASM International (2003)
- GB/T 16253 / ZG15Cr1Mo — SAC (2019)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.