Valves
Gate valves: cast, forged and through-conduit
Gate valves are the standard isolation valve on refinery, process and utility piping, and on pipelines where a full, unobstructed bore is required. CRS PLUS sources cast steel wedge gate valves, forged small-bore gate valves and through-conduit slab and expanding gate valves, quoted by size, pressure class, end connection, body and trim material and operator.
Gate valves we quote
Sourced through the qualified supplier base. Sizes, ratings and grades are shown as ranges; send your bill of materials and every line is quoted against its exact specification.
| Product | Standard | Sizes | Rating / class | Materials |
|---|---|---|---|---|
| Cast steel wedge gate valve, bolted bonnet | API 600 / ISO 10434 / ASME B16.34 | NPS 2 to 42 | Class 150 to 2500 | A216 WCB, A352 LCC, A217 WC6 / WC9, A351 CF8M |
| Pressure-seal bonnet gate valve | API 600 / ASME B16.34 | NPS 2 to 24 | Class 600 to 2500 | A216 WCB, A217 WC9 / C12A |
| Forged steel gate valve, small bore | API 602 / ISO 15761 | NPS ½ to 2 | Class 800 to 2500 | A105N, A350 LF2, A182 F11 / F22 / F316 |
| Through-conduit slab gate valve | API 6D / ISO 14313 | NPS 2 to 36 | Class 150 to 2500 | A216 WCB, A105N, A352 LCC |
| Expanding gate valve | API 6D | NPS 2 to 36 | Class 150 to 1500 | A216 WCB, A105N |
| Wellhead and Christmas-tree gate valve | API 6A | 1 13/16 to 7 1/16 in | 2,000 to 15,000 psi | AISI 4130, 410 SS trims; material class AA to HH |
| Stainless and corrosion-resistant gate valve | API 603 / ASME B16.34 | NPS ½ to 24 | Class 150 to 600 | A351 CF8M / CF3M, duplex 4A / 5A |
| Gear-operated and actuated gate valve | API 600 / API 6D + operator | NPS 6 to 48 | Class 150 to 2500 | As valve body; gearbox or electric actuator to specification |
How a gate valve is specified
A gate valve line states size, pressure class, end connection, body material, trim, bonnet type and operator — for example "6 in class 300 gate valve, API 600, RF flanged, A216 WCB body, trim 8, bolted bonnet, handwheel". The trim number, defined in API 600 and API 602, fixes the materials of the stem, wedge and seat faces; trim 8 (13Cr with hard-faced seats) is the common general-purpose choice for carbon steel valves, with trim 12 or 16 for stainless service.
Above roughly NPS 8 in class 150, or smaller sizes at higher classes, a bevel gear operator is normally specified to keep the handwheel force manageable. Actuated valves are quoted with actuator type, supply and fail position stated.
Gate, ball or globe valve
A gate valve is an on-off isolation valve: fully open it offers a straight-through bore with very low pressure drop, but it should not be used to throttle flow, which erodes the wedge and seats. A ball valve isolates with a quarter turn and is quicker to operate; a gate valve is often preferred for high-temperature service, larger sizes at lower cost, and lines that stay open for long periods. A globe valve is the choice where flow must be regulated.
Documentation and supply terms
- Mill test certificate
- EN 10204 3.1 certificate for every line, traceable to the heat number marked on the item. EN 10204 3.2 with third-party witness on request.
- Marking
- Material grade, size, rating and heat number marked on each item to the governing standard (MSS SP-25 for valves, flanges and fittings).
- Inspection
- Positive material identification, dimensional checks and third-party inspection arranged where the project specifies them.
- Sour and low-temperature service
- NACE MR0175 / ISO 15156 hardness limits and impact testing applied where the piping class calls for them, and stated on the certificate.
- Quotation
- Each line states the standard, grade, origin, lead time and certification before you commit. Listing does not indicate stock held by CRS PLUS.
Questions
Frequently asked questions
What is the difference between API 600 and API 602 gate valves?
API 600 covers bolted-bonnet steel gate valves, typically cast, from NPS 1 upwards for refinery and process service. API 602 covers compact forged steel gate, globe and check valves in NPS 4 and smaller, typically used on small-bore lines in classes 800 and 1500.
What is a through-conduit gate valve?
A through-conduit (slab or expanding) gate valve has a gate with a port bored through it; when open, the port lines up with the pipe to give a smooth, continuous bore. It is used on pipelines to API 6D because it allows pigging and seals in both directions.
Can a gate valve be used to control flow?
No. A gate valve is designed to be fully open or fully closed. Partly open, the flow erodes the wedge and seats and can cause vibration. A globe valve or a control valve is used where flow must be regulated.
What does "rising stem" mean?
On a rising-stem (OS&Y, outside screw and yoke) gate valve, the stem rises as the valve opens, so its position shows at a glance whether the valve is open or closed, and the stem threads stay out of the process fluid. It is the standard design for API 600 valves. Non-rising-stem valves are used where headroom is limited.
What is a pressure-seal bonnet?
In a pressure-seal valve, line pressure pushes the bonnet seal ring harder against the body as pressure rises, giving a tight seal without heavy bonnet bolting. It is used in high-pressure and high-temperature service, typically class 600 and above, including steam lines.
What documentation comes with a gate valve?
Each valve is shell and seat tested to API 598 or API 6D and supplied with the test certificate and EN 10204 3.1 material certificates for pressure-containing parts. Fugitive-emission testing, NACE MR0175 compliance and third-party inspection are added where specified.
Related pages
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Manufacturer and brand names, where mentioned, are used for identification only. CRS PLUS sources these products through its qualified supplier base and holds no distributor, reseller or agency appointment from any manufacturer.