API 600 Flanged Cast Steel Gate Valve — Class 600, A216 WCB, RF/RTJ/BW (NPS 2"–42")

The API 600 flanged cast steel gate valve on this page is the Class 600 (600LB) rising stem (OS&Y) bolted bonnet design, with flexible wedge and backseat. The standard body is ASTM A216 WCB; ASTM A351 CF8 (304) and CF8M (316) bodies are available for corrosive service. End connections include raised face (RF) and ring type joint (RTJ) to ASME B16.5, butt-weld to ASME B16.25, and socket-weld to ASME B16.11. Sizes run from NPS 2" to NPS 42". The 6" (DN150) Class 600 RF configuration is the most frequently specified size for oil and gas gathering and process lines.

Application

Class 600 cast steel gate valves are commonly specified in oil and gas production and gathering, refinery and petrochemical process lines, water treatment and high-pressure utility service. For sour service the valve can be supplied to NACE MR0175 / ISO 15156 on request; RTJ ends are frequently combined with NACE compliance at this pressure class.

Standards

Design and Manufacture: Cast steel gate valve to API 600 or API 6D.
Inspection and Test: API 598, API 600 or API 6D.
End flange dimension: ASME B16.5 (for NPS ≤ 24); API 605 or ASME B16.47 series A / MSS SP-44 (for NPS > 24).
BW end dimension: ASME B16.25.
Socket-weld dimension: ASME B16.11.
Face to face and end to end: ASME B16.10.
Pressure-temperature ratings: ASME B16.34.

Quick Details

1. Valve Type & Model: Gate Valves, Z40H
2. Bonnet Type: OS&Y, Bolted Bonnet, B.B.
3. Wedge Type: Flexible Wedge
4. Valve Size: 6" (DN150); other sizes NPS 2–42 available
5. Pressure Ratings: ASME Class 600 / 600LB / CL600
6. Materials Available in: A216 WCB, A351 CF8, A351 CF8M
7. Various trim materials are available to suit different service conditions
8. Actuator: Manual, Handwheel, Gear Operated
9. Special Requirement: NACE MR0175 on request

Selection Notes: Trim, RTJ vs RF and Sour Service

At Class 600 the choice of end connection carries more weight than at Class 150. RF (raised face) is the standard ASME B16.5 flanged connection and remains the default for non-sour process lines. RTJ (ring type joint) uses a metal ring gasket seated in a machined groove, giving a metal-to-metal seal that is preferred for high-pressure, high-temperature and sour service. Both facings are available on this valve, and the Class 600 dimension table below lists separate face-to-face lengths for RF, RTJ and BW.

Trim 1 (13Cr seat and 13Cr wedge) is the standard selection for general service. Trim 5 (Stellite on seat and wedge sealing surfaces) is preferred where erosion and wear resistance is required, such as throttling duty or high-velocity lines. Trim 8 (13Cr wedge with STL seat) is a middle-ground specification frequently requested in refinery and petrochemical line schedules. For corrosive media, the body, bonnet and trim can be supplied in ASTM A351 CF8 (304) or CF8M (316), with A182 F304/F316 stems, A193 B8/B8M bolting and A194 8/8M nuts.

For sour service, NACE MR0175 / ISO 15156 compliance is available on request; the H₂S partial pressure, operating temperature, CO₂ content and chloride concentration from your line conditions are needed to confirm the correct material and hardness specification before production.

Features

1. Bonnet Gasket Style
Stainless steel + flexible graphite wound gasket is used for Class 600 gate valve.

2. Packing Seal
As usual, flexible graphite is used for packing material. PTFE or combined packing material can also be used if requested by the customer.

3. Body and Bonnet Connection
Class 600LB gate valves are usually connected with bolted bonnet design.

4. Disc Design
NPS ≥ 2 gate valves are flexible wedge gate.

5. Seat
For carbon steel gate valve, the seat is usually forged steel. The seat sealing surface is overlay welded with hard alloy specified by the customer. For stainless steel gate valve, the seat is integral with body, or it can be machined directly after hard alloy welding.

6. Backseat Design
All gate valves have backseat design. In most cases, the carbon steel gate valve is fitted with a renewable back seat. For stainless steel gate valve, the back seat is machined directly in the bonnet or machined after welding.

7. Stem Design
The stem is integral forged design. The minimum diameter of the stem shall be as per the standard requirement.

8. Stem Nut
Usually, the stem nut is made of ASTM A439 D2. It can also be made of copper alloy or other materials if requested by the customer.

9. Operation
Hand wheel or bevel gear box is usually used for gate valve operation.

Cast Steel Gate Valve Parts and Material List (Class 600LB)

Parts No. 17 Stem Nut: original source lists "A439 02" in the CF8 column — corrected to A439 D2 (same material as the other columns). Confirm against the material certificate before publication.

Main Connection Dimensions — Class 600LB (mm)

Dimensions in mm. L = face-to-face (RF / RTJ) or end-to-end (BW) per ASME B16.10. RF and RTJ flange dimensions per ASME B16.5 for NPS ≤ 24; ASME B16.47 series A for NPS > 24. NPS 38 and 40 are not listed in the original Class 600 dimension series. RTJ groove dimensions for NPS 42 (Y, P, E, F) are to be confirmed with our engineering team before ordering.

Frequently Asked Questions