Cast Steel Gate & Globe Valves
BS 1873 cast steel globe valves are used on steam, condensate and process lines in petrochemical and power plants for both tight shutoff and flow regulation. The bolted bonnet design is preferred in mid classes, the pressure seal design at high pressure and temperature.
Overview
All designs include a backseat: with the valve fully open, the stem seats against the bonnet and isolates the packing from pressure. Carbon steel valves use a renewable backseat ring; stainless steel valves use an integrally machined backseat surface. The disc is flat for isolation, or plug or parabolic for flow regulation. For steam and high differential pressure, seat and disc faces are hard-faced with Stellite.
Technical specifications
| Size | ½”–16″ (DN15–DN400) within the scope of BS 1873; larger sizes based on ASME B16.34, on a project basis |
|---|---|
| Pressure class | ASME Class 150–2500 |
| Bonnet | Bolted (Class 150–900), pressure seal (Class 900–2500) |
| Disc | Flat, plug, parabolic |
| Materials | WCB, WC6, WC9, LCC, CF8M |
| End connections | RF / RTJ flanged, butt-weld |
| Testing | API 598 |
Key features
- Backseat protects the packing
- Plug or parabolic disc for flow regulation
- Stellite hard-faced seat and disc
- Cr-Mo body for high temperature
Face-to-face dimensions (mm)
Flanged face-to-face dimensions of BS 1873 / ASME B16.34 cast steel globe valves (ASME B16.10):
| NPS | DN | Class 150 | Class 300 | Class 600 |
|---|---|---|---|---|
| 2 | 50 | 203 | 267 | 292 |
| 2½ | 65 | 216 | 292 | 330 |
| 3 | 80 | 241 | 318 | 356 |
| 4 | 100 | 292 | 356 | 432 |
| 6 | 150 | 406 | 444 | 559 |
| 8 | 200 | 495 | 559 | 660 |
| 10 | 250 | 622 | 622 | 787 |
| 12 | 300 | 698 | 711 | 838 |
Values are for raised-face (RF) flanged ends and conform to ASME B16.10. Ring-type joint (RTJ) ends are slightly longer; butt-weld (BW) end-to-end dimensions are listed separately in the standard. Exact dimensions are shown on the general arrangement (GA) drawing supplied with the quotation.
Typical part materials
| Part | Carbon steel | Low temperature | Stainless steel | Alloy steel (high temperature) |
|---|---|---|---|---|
| Body, bonnet, disc | A216 WCB | A352 LCB / LCC | A351 CF8, CF8M, CF3, CF3M | A217 WC6, WC9, C5 |
| Seat ring | A105N (hardfaced) | A350 LF2 | Same stainless grade as body | A182 F11, F22, F5 |
| Stem | A182 F6a (13Cr) | A182 F304 | A182 F304, F316, F304L, F316L | A182 F6a |
| Stud bolts / nuts | A193 B7 / A194 2H | A320 L7 / A194 7 | A193 B8, B8M / A194 8, 8M | A193 B16 / A194 4 |
| Gland bushing, backseat | A182 F6a | A182 F304 | Same stainless grade as body | A182 F6a |
In all material groups, the standard gasket is spiral-wound SS304/SS316 with graphite filler and the standard packing is flexible graphite (PTFE on request). The stem nut is austenitic ductile iron (A439 D2) or copper alloy, and the handwheel is malleable iron. For sour (H₂S) service, materials and hardness are selected to NACE MR0175 / ISO 15156.
Globe valve trims are designated with the same numbering as gate valves; for steam and throttling service, a hardfaced disc and seat (trim 5, 8 or 12) are recommended.
Documentation and testing
On industrial projects the documentation package matters as much as the valve. We confirm the certificate and test scope for every line item at quotation stage:
- EN 10204 3.1 material certificates for pressure-retaining and wetted parts, traceable by heat number
- EN 10204 3.2 with third-party inspection, on request
- Pressure test reports to API 598 or EN 12266-1: shell, seat and, where specified, gas tests
- Fire-test certificates (API 607 / ISO 10497) for fire-safe type-tested designs
- PMI reports for alloy and stainless materials
- Dimensional, visual and coating inspection records
- PED 2014/68/EU CE declaration for equipment within its scope
- NACE MR0175 / ISO 15156 compliance statement for sour (H₂S) service
Technical datasheet
Frequently Asked Questions
Can a BS 1873 globe valve be used instead of API 623?
BS 1873 and API 623 share similar design principles, but wall thickness, stem diameter and test requirements are not identical. We quote to the standard named in the specification and state any difference clearly in our quotation.
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View detailsRequest a quote: BS 1873 Cast Steel Globe Valve
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