ASTM A217 Grade WC6
1¼Cr–½Mo alloy steel casting. Used above the graphitization limit of carbon steel, in high-temperature steam and hot oil lines.
- Rp0.2 · MPa
- ≥ 275
- Rm · MPa
- ≥ 485
- TEMPERATURE
- −29 … +593 °C
- COST

Chemical composition
%. ASTM A217. Residual elements (Cu, W) and their total are limited separately in the standard.
Mechanical properties
| STANDARD · CONDITION | Rp0.2 MPa | Rp1.0 MPa | Rm MPa | A % | KV J |
|---|---|---|---|---|---|
| ASTM A217 · WC6 | 275 | — | ≥ 485 | 20 | — |
| EN 10213 · G17CrMo5-5 (+QT) | 315 | — | 490–690 | 20 | — |
Room temperature, normalized + tempered. Hardness ≤ 215 HB. Z ≥ 35%.
ASME B16.34 pressure-temperature ratings
| CLASS · bar | −29 … 38 °C | 100 °C | 200 °C | 300 °C | 400 °C | 500 °C |
|---|---|---|---|---|---|---|
| Class 150 | 19.8 | 17.7 | 13.8 | 10.2 | 6.5 | 2.8 |
| Class 300 | 51.7 | 51.5 | 48.0 | 42.9 | 36.5 | 25.7 |
| Class 600 | 103.4 | 103.0 | 95.9 | 85.7 | 73.3 | 51.5 |
| Class 900 | 155.1 | 154.4 | 143.9 | 128.6 | 109.8 | 77.2 |
| Class 1500 | 258.6 | 257.4 | 239.8 | 214.4 | 183.1 | 128.6 |
| Class 2500 | 430.9 | 429.0 | 399.6 | 357.1 | 304.9 | 214.4 |
Standard class, bar. Material group: WC6. Greyed values are outside the material's service range (−29 … +593 °C). Flanged-end ratings end at 538 °C.
Service temperature
This is the limit of the material itself. A valve's service temperature is usually set by the seal and seat materials; product pages give it for each seal option.
Physical properties and heat treatment
- HEAT TREATMENT
- Normalizing + tempering (≥ 595 °C).
Media suitability GENERAL TREND
Emsal assessment. The final choice is made from corrosion tables, taking concentration, temperature, chloride content and flow velocity into account.
Strengths and weaknesses
Strengths
- Creep strength at high temperature
- Resistant to graphitization
- Proven in steam service
Weaknesses
- Requires preheating and post-weld heat treatment
- Limited corrosion resistance
Manufacturing and use
- ECONOMY
- Low to medium.
- MANUFACTURING METHODS
- Sand casting + normalizing and tempering
- TYPICAL VALVE PARTS
- Body · Bonnet
Surface protection
- Wet paintIndustrial wet paint systemExternal surface; silicone-based heat-resistant paint is needed at high temperature
Source: ASTM A217. Values compiled and verified by Emsal Vana; for binding values, refer to the current edition of the standard and the material certificate.