Steel A217
ASTM A217
ASTM A217 covers martensitic and ferritic Cr-Mo alloy steel castings — grades WC1, WC4, WC5, WC6, WC9, WC11, C5, C12 and C12A — intended for valves, flanges and fittings in high-temperature, high-pressure steam and petrochemical service.
Reference datasheet — A217 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 WC6 condition
A217 tempers and conditions
A217 is supplied in 9 conditions, soft to hard. WC6 is the default FabDigit quotes; the values on this page are for it.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
C-0.5Mo cast steel, normalized and tempered | Cheapest A217 grade for moderate-temperature steam service up to about 450–470 °C where graphitization is not a concern. | 285 | 495 | 28 | 150 HB | 44 W/m·K |
Ni-Cr-Mo cast steel, normalized and tempered | Nickel-bearing grade offering better hardenability and toughness in heavier valve-body sections than WC1. | 330 | 545 | 24 | 180 HB | 42 W/m·K |
Ni-Cr-Mo (1Mo) cast steel, normalized and tempered | Like WC4 but with ~1 % Mo for slightly better elevated-temperature creep strength in thick castings. | 335 | 550 | 24 | 185 HB | 41 W/m·K |
WC6Default 1.25Cr-0.5Mo cast steel, normalized and tempered | The default stocked A217 grade: 1.25Cr-0.5Mo valve and flange castings for steam and hydrocarbon service up to ~540 °C. | 345 | 550 | 24 | 170 HB | 40 W/m·K |
2.25Cr-1Mo cast steel, normalized and tempered | Standard grade for hot hydrogen and high-temperature steam service (Nelson-curve applications) up to about 580 °C. | 350 | 560 | 24 | 180 HB | 36 W/m·K |
1.25Cr-0.5Mo (higher C/Si) cast steel, quenched or normalized and… | Higher-strength version of the 1.25Cr-0.5Mo chemistry when 345 MPa minimum yield is required in the casting. | 415 | 620 | 22 | 17 HRC | 42 W/m·K |
5Cr-0.5Mo cast steel, normalized/quenched and tempered | Choose for refinery high-temperature sulfidation and hot-oil service where 5 % Cr scale resistance is needed. | 470 | 690 | 21 | 16 HRC | 34 W/m·K |
9Cr-1Mo cast steel, normalized and tempered | 9 % Cr martensitic casting for the hottest conventional steam and refinery service where oxidation resistance outranks toughness. | 470 | 690 | 21 | 16 HRC | 27 W/m·K |
9Cr-1Mo-V (cast P91/CA6NM-class Grade 91), normalized and tempered | Cast Grade 91: V/Nb/N-microalloyed 9Cr with the highest creep strength in A217, used for supercritical steam valves and headers. | 470 | 660 | 21 | 21 HRC | 27 W/m·K |
What is A217?
ASTM A217 covers martensitic and ferritic Cr-Mo alloy steel castings — grades WC1, WC4, WC5, WC6, WC9, WC11, C5, C12 and C12A — intended for valves, flanges and fittings in high-temperature, high-pressure steam and petrochemical service. Castings are normalized and tempered to roughly 170 HB, with typical values of 345 MPa yield, 550 MPa tensile, 24 % elongation, 205 GPa modulus, 40 W/m·K conductivity, density 7.84 g/cm³ and service to 540 °C. Welding is routine but preheat and PWHT are mandatory, and corrosion resistance is low — the 5Cr and 9Cr grades resist oxidation and sulfidation better than WC6/WC9, but none are stainless. A217 has a density of 7.84 g/cm³ (0.283 lb/in³), lighter than 78% of steel grades. It melts at 1,435°C (2,615 °F). A217 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 205 GPa (29.7 Msi).
What is A217 used for?
- valve bodies
- pressure vessel fittings
- steam piping components
- petrochemical process equipment
Advantages
- High service temperature — 540°C (1,004 °F), better than 93% of steel grades
- Tough — resists crack growth — 115 MPa·√m (104.7 ksi·√in), better than 77% of steel grades
Limitations
- Limited formability — 18/100, worse than 84% of steel grades
- Low strength — 345 MPa (50 ksi), worse than 75% of steel grades
A217 properties
Typical room-temperature values for A217-WC6; bars are the position among steel grades.
Physical3
A217 has a density of 7.84 g/cm³ (0.283 lb/in³), lighter than 78% of steel grades. It melts at 1,435°C (2,615 °F).
Mechanical16
A217 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 205 GPa (29.7 Msi).
Thermal6
A217 is rated for continuous service to 540°C (1,004 °F). It conducts heat at 40 W/m·K (23.1 BTU/hr·ft·°F), worse than 64% of steel grades. Thermal expansion is 12.2 µm/m·K (6.78 µin/in·°F).
Electrical3
A217 conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (16/100), better than 79% of steel grades.
Sustainability4
Producing a kilogram of A217 takes about 29 MJ of energy and emits 2.1 kg of CO₂ — less than 53% of steel grades. Typical recycled content is 70%.
Manufacturability8
A217's machinability is good (55/100, better than 62% of steel grades); weldability good (65/100); formability poor (18/100).
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. A217 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with A217
Is A217 easy to machine?
Machine after normalize-and-temper at 150–215 HB; carbide tooling, rigid setups, and allowance for casting skin/sand inclusions; 9Cr grades (C12/C12A) cut noticeably harder and work-harden edges.
Can A217 be welded?
Weldable with matched low-alloy or 9Cr filler (E8018-B2, E9018-B3, E9015-B9) but requires preheat 150–250 °C (C12A ≥ 200 °C), controlled interpass, and mandatory PWHT — 700–760 °C for WC6/WC9, 730–775 °C for C12A.
Can A217 be formed, bent or molded?
Sand or investment cast only; needs good feeding/risering for heavy valve sections, and full re-austenitize + temper after any major weld repair to restore properties.
A217 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 WC6 (default); WC1 0.25 max, C12A 0.08–0.12 | 0.05 – 0.2 | 0.13 |
| MnWC6 | 0.5 – 0.8 | 0.65 |
| SiWC6 max | ≤ 0.6 | 0.4 |
| CrWC6; WC9 2.00–2.75, C5 4.00–6.50, C12 8.0–10.0, C12A 8.0–9.5 | 1 – 1.5 | 1.25 |
| MoWC6; WC9/C12 0.90–1.20, C12A 0.85–1.05 | 0.45 – 0.65 | 0.55 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.05 | 0.02 |
| Niresidual for WC6; WC4 0.70–1.10, WC5 0.60–1.00 | ≤ 0.5 | 0.2 |
| Vresidual for WC6; C12A 0.18–0.25 intentional | ≤ 0.03 | 0.01 |
| NbC12A only, 0.06–0.10 (Cb) | ≈ 0.08 | 0.08 |
| NC12A only, 0.030–0.070 | ≈ 0.05 | 0.05 |
| Fe | balance | — |
What surface finishes work on A217?
Not anodizable; typically shot-blasted then painted, aluminized, or left bare inside insulated high-temperature piping — protect machined faces against atmospheric rusting.
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 A217 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does A217 cost?
A217 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.
A217 — frequently asked
What is A217 used for?
A217 is typically used for valve bodies, pressure vessel fittings, steam piping components and petrochemical process equipment. In short: high-temperature Cr-Mo castings; standard for steam valves; covers WC1 through C12A.
What is the yield strength of A217?
A217 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 9 listed tempers.
Is A217 easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machine after normalize-and-temper at 150–215 HB; carbide tooling, rigid setups, and allowance for casting skin/sand inclusions; 9Cr grades (C12/C12A) cut noticeably harder and work-harden edges.
Can A217 be welded?
Yes — weldability is rated good (65/100). Weldable with matched low-alloy or 9Cr filler (E8018-B2, E9018-B3, E9015-B9) but requires preheat 150–250 °C (C12A ≥ 200 °C), controlled interpass, and mandatory PWHT — 700–760 °C for WC6/WC9, 730–775 °C for C12A.
What surface finishes work on A217?
Not anodizable; typically shot-blasted then painted, aluminized, or left bare inside insulated high-temperature piping — protect machined faces against atmospheric rusting.
Can A217 be formed, bent or molded?
Sand or investment cast only; needs good feeding/risering for heavy valve sections, and full re-austenitize + temper after any major weld repair to restore properties.
What is the maximum service temperature of A217?
A217 is rated for continuous use to about 540°C (1,004 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between A217-WC6 and A217-C5?
WC6 is the default condition — the default stocked A217 grade: 1.25Cr-0.5Mo valve and flange castings for steam and hydrocarbon service up to ~540 °C. C5: choose for refinery high-temperature sulfidation and hot-oil service where 5 % Cr scale resistance is needed. Yield strength is 345 MPa in WC6 versus 470 MPa in C5.
How much does A217 cost?
A217 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 A217/A217M Standard Specification for Steel Castings, Martensitic Stainless and Alloy, for Pressure-Containing Parts, Suitable for High-Temperature Service — ASTM International (2021)
- ASME BPVC Section II Part D — Materials Properties — ASME (2023)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Steel Castings Handbook — Steel Founders' Society of America (1995)
- API RP 941 — Steels for Hydrogen Service at Elevated Temperatures — API (2016)
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.