Steel WC6 N+T
Heat-treated state · default condition
GB WC6 · ASTM A217 Grade WC6
N+T = normalized and tempered
Standard supply condition for A217 WC6 valve bodies and fittings; best balance of strength, toughness and creep behaviour.
Values for the N+T condition
Other WC6 tempers and conditions
WC6 is listed in 3 conditions; see the grade overview at WC6.
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+TDefaultThis page 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 N+T?
WC6 N+T is WC6 heat treated to N+T — standard supply condition for A217 WC6 valve bodies and fittings; best balance of strength, toughness and creep behaviour. WC6 N+T 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). WC6 N+T 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).
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 N+T properties
Typical room-temperature values for WC6 N+T; 11 are specific to this condition. Other listed values are WC6 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
WC6 N+T 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 N+T 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 N+T 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 N+T 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 N+T 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 N+T'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. Confirm any required mill or lot documentation when quoting.
Working with WC6 N+T
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.
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.
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 | — |
WC6 N+T — frequently asked
What is WC6 N+T used for?
WC6 N+T 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 N+T?
WC6 N+T 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 N+T 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 N+T 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 N+T?
Shot blast then epoxy/zinc-rich paint or ENP for corrosion protection; no anodizing, chrome or hardfacing overlays common on seat areas.
Can WC6 N+T 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 N+T?
WC6 N+T 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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.