MEDIA GUIDE
Steam Service Valves
A materials-and-temperature duty before anything else.
Steam is a materials-and-temperature duty before anything else: metal seats, graphite packing and thermal-expansion behaviour govern. Above 250 °C avoid wedge gates on isolation (thermal binding — parallel-slide or globe is the documented practice); above 425 °C alloy-steel bodies (WC6/WC9) replace WCB. Drain and warm-up provisions belong in the RFQ.
Service flags: steam duty.
Materials at a glance
| Material | Rating | Up to |
|---|---|---|
| Carbon steel (ASTM A216 WCB) | Excellent | 425 °C |
| 1.25Cr-0.5Mo alloy steel (ASTM A217 WC6) | Excellent | 593 °C |
| 2.25Cr-1Mo alloy steel (ASTM A217 WC9) | Excellent | 593 °C |
| Stainless steel 304 (ASTM A351 CF8) | Excellent | 538 °C |
| Stainless steel 316 (ASTM A351 CF8M) | Excellent | 538 °C |
Ratings: Excellent / Good / Conditional / Not recommended, from this site's boundary-and-medium data set. The manufacturer's data sheet for the specific product governs.
What drives the choice
- Metal seats, graphite packing and thermal-expansion behaviour govern
- Above 250 °C avoid wedge gates on isolation — thermal binding; parallel-slide or globe is the documented practice
- Above 425 °C alloy-steel bodies (WC6/WC9) replace WCB
- Drain and warm-up provisions belong in the RFQ
Where the boundaries sit
- Superheated-steam duties sit close to the handover lines — the report states which one binds
Related reading
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