Valve Body Investment Casting and CNC Finishing Guide
Valve Body Materials
Valve body manufacturing selects materials for fluid compatibility. CF8M (316 cast) for corrosive, WCB (carbon steel) for general service, CF8 (304) for moderate corrosion. Pressure classes 150-2,500#.
Temperature range: -29°C to 425°C for carbon steel, -196°C to 800°C for stainless grades.
| Grade | Material | Service | Process |
|---|---|---|---|
| WCB | Cast carbon steel | General | Sand/Investment |
| CF8 | Cast 304 | Corrosion moderate | Investment |
| CF8M | Cast 316 | Chemical | Investment |
| WC6 | Alloy steel | High temp | Investment |
Investment Casting
Wax injection to ±0.5mm. Ceramic shell 5-8 layers. Pour temperature 1,550-1,650°C for steel. Cast surface Ra 3.2-6.3. Wall thickness ±1mm. X-ray inspection for internal soundness.
Investment casting produces complex flow passages and integral flanges, reducing weld requirements and improving reliability.
| Step | Process | Result |
|---|---|---|
| Wax Pattern | Injection | ±0.5mm detail |
| Shell | Ceramic layers | Strength |
| Pour | Metal casting | Near net shape |
| NDT | X-ray/FPI | Soundness |
CNC Finishing
CNC of flange faces, seat bores and gasket surfaces. Seat tolerance ±0.05mm for bubble-tight shutoff. Shell test at 1.5x rated. Seat test at 1.1x rated (Class VI leakage). Torque test for stem connection.
Face-to-face dimension per ASME B16.10. Coating per customer specification. Full documentation package.
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