Steel WC6
GB WC6 · ASTM A217 Grade WC6
WC6 is a 1.25Cr-0.5Mo cast steel in the ASTM A217 family, supplied normalized and tempered, quenched and tempered, or annealed, and it is the most commonly stocked Cr-Mo casting grade for valve bodies and fittings.
Reference datasheet — WC6 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
WC6 tempers and conditions
WC6 is supplied in 3 conditions, soft to hard. N+T is the default FabDigit quotes; the values on this page are for it.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Non-code intermediate condition used by foundries to soften castings for rough machining or repair welding before final N+T/Q+T. | 275 | 470 | 28 | 145 HB | 8 % IACS |
N+TDefault Normalized and tempered | Standard supply condition for A217 WC6 valve bodies and fittings; best balance of strength, toughness and creep behaviour. | 340 | 530 | 26 | 170 HB | — |
Quenched and tempered | Choose for heavy-section castings or when higher yield strength and low-temperature toughness are required. | 400 | 585 | 24 | 190 HB | — |
What is WC6?
WC6 is a 1.25Cr-0.5Mo cast steel in the ASTM A217 family, supplied normalized and tempered, quenched and tempered, or annealed, and it is the most commonly stocked Cr-Mo casting grade for valve bodies and fittings. It is used in power and petrochemical service up to about 470 °C, with 340 MPa yield, 530 MPa tensile, 26 % elongation and about 170 HB in the default condition. Machinability rates about 55 and weldability about 65, so preheat and high-temperature PWHT are mandatory. It has no corrosion resistance; move to WC9 (2.25Cr-1Mo) when service temperature exceeds its range. WC6 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F). WC6 has a yield strength of 340 MPa (49.3 ksi) and a tensile strength of 530 MPa (76.9 ksi) — weaker than 76% of steel grades. Elongation at break is 26% and the elastic modulus is 207 GPa (30 Msi).
What is WC6 used for?
- Steam valve bodies
- Pump casings
- High-temperature piping fittings
Advantages
- Tough — resists crack growth — 130 MPa·√m (118.3 ksi·√in), better than 89% of steel grades
- High service temperature — 470°C (878 °F), better than 87% of steel grades
- Ductile — tolerates forming and impact — 26%, better than 82% of steel grades
Limitations
- Limited formability — 20/100, worse than 80% of steel grades
- Low strength — 340 MPa (49.3 ksi), worse than 76% of steel grades
WC6 properties
Typical room-temperature values for WC6-N+T; bars are the position among steel grades.
Physical3
WC6 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
WC6 has a yield strength of 340 MPa (49.3 ksi) and a tensile strength of 530 MPa (76.9 ksi) — weaker than 76% of steel grades. Elongation at break is 26% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
WC6 is rated for continuous service to 470°C (878 °F). It conducts heat at 42 W/m·K (24.3 BTU/hr·ft·°F), worse than 56% of steel grades. Thermal expansion is 12.2 µm/m·K (6.78 µin/in·°F).
Electrical2
WC6 has an electrical resistivity of 2.2×10⁻⁷ Ω·m.
Chemical & Environmental3
Corrosion resistance is poor (16/100), better than 79% of steel grades.
Sustainability4
Producing a kilogram of WC6 takes about 27 MJ of energy and emits 2.2 kg of CO₂ — less than 59% of steel grades. Typical recycled content is 80%.
Manufacturability7
WC6's machinability is good (55/100, better than 62% of steel grades); weldability good (65/100); 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. WC6 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with WC6
Is WC6 easy to machine?
Machines like normalized 4130-class steel; carbide tooling at moderate speed, watch for hard spots and sand inclusions on as-cast surfaces.
Can WC6 be welded?
P-No.4 material: preheat 150–200 °C, use E8018-B2/ER80S-B2 filler, PWHT 675–730 °C to restore toughness and meet code.
Can WC6 be formed, bent or molded?
Supplied as sand castings; give generous fillets and directional solidification with risers/chills to avoid shrinkage in heavy valve sections.
WC6 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 | 0.05 – 0.2 | 0.15 |
| Mn | 0.5 – 0.8 | 0.65 |
| Si | ≤ 0.6 | 0.4 |
| Pimpurity | ≤ 0.04 | 0.02 |
| Simpurity | ≤ 0.05 | 0.02 |
| Cr | 1 – 1.5 | 1.25 |
| Mo | 0.45 – 0.65 | 0.55 |
| Niresidual | ≤ 0.5 | 0.15 |
| Curesidual | ≤ 0.5 | 0.15 |
| Wresidual | ≤ 0.1 | 0.02 |
| Vresidual | ≤ 0.03 | 0.01 |
| Fetotal residuals Cu+Ni+W+V ≤ 1.00% | balance |
What surface finishes work on WC6?
Shot blast then epoxy/zinc-rich paint or ENP for corrosion protection; no anodizing, chrome or hardfacing overlays common on seat areas.
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 WC6 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- A217 Grade WC6
How much does WC6 cost?
WC6 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.
WC6 — frequently asked
What is WC6 used for?
WC6 is typically used for steam valve bodies, pump casings and high-temperature piping fittings. In short: baseline 1.25Cr-0.5Mo casting; common steam valve grade; codes-ready Cr-Mo casting.
What is the yield strength of WC6?
WC6 has a typical yield strength of 340 MPa (49.3 ksi) and a tensile strength of 530 MPa (76.9 ksi) — weaker than 76% of steel grades. Strength varies by condition: see the 3 listed tempers.
Is WC6 easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machines like normalized 4130-class steel; carbide tooling at moderate speed, watch for hard spots and sand inclusions on as-cast surfaces.
Can WC6 be welded?
Yes — weldability is rated good (65/100). P-No.4 material: preheat 150–200 °C, use E8018-B2/ER80S-B2 filler, PWHT 675–730 °C to restore toughness and meet code.
What surface finishes work on WC6?
Shot blast then epoxy/zinc-rich paint or ENP for corrosion protection; no anodizing, chrome or hardfacing overlays common on seat areas.
Can WC6 be formed, bent or molded?
Supplied as sand castings; give generous fillets and directional solidification with risers/chills to avoid shrinkage in heavy valve sections.
What is the maximum service temperature of WC6?
WC6 is rated for continuous use to about 470°C (878 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between WC6 N+T and WC6-ANN?
N+T is the default condition — standard supply condition for A217 WC6 valve bodies and fittings; best balance of strength, toughness and creep behaviour. ANN: non-code intermediate condition used by foundries to soften castings for rough machining or repair welding before final N+T/Q+T. Yield strength is 340 MPa in N+T versus 275 MPa in ANN.
How much does WC6 cost?
WC6 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 — 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 (SA-217 WC6) — ASME (2023)
- ASME B16.34 — Valves, Flanged, Threaded and Welding End — ASME (2020)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- GB/T 16253 (ZG15Cr1Mo ) (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.