Overall, this section covers scotch yoke actuator housing casting. It also covers investment cast actuator housing WCB CF8M. It also covers quarter turn actuator housing manufacturer.
Specifications
| Parameter | Detail |
|---|---|
| Material | ASTM A216 WCB carbon steel, ASTM A351 CF8M and CF8 stainless steel, ASTM A995 4A / 2205 duplex; 17-4PH H900 or AISI 420 for yoke, pins and wear plates |
| Process | Water glass lost wax for large housings and thick spring-cartridge sections, silica sol lost wax for smaller and medium-size housings where CT4 to CT6 is required |
| Dimensional tolerance | ISO 8062 CT4 to CT6 (silica sol) or CT6 to CT7 (water glass); cylinder bore, guide slot and mounting faces finish machined to drawing |
| Surface finish | As-cast Ra 3.2 to 6.3 micrometres (silica sol) or Ra 6.3 to 12.5 micrometres (water glass); machined bore and sealing faces Ra 1.6 to 3.2 micrometres |
| Machining | Machining covers CNC boring of the cylinder bore and milling of the yoke guide slot and spring-cartridge seat. It also takes in the ISO 5211 valve mounting flange, end flanges, indicator boss and tapped ports. |
| Pressure class | Housings for pneumatic and hydraulic scotch yoke actuators, designed for air supply up to 12 bar and hydraulic supply to 210 bar, mounted on ASME class 150 to 600 valves |
| Inspection & certificates | Documentation covers the EN 10204 3.1 material certificate (type 3.2 on request) and heat-lot traceability. It also covers MT or PT on load-bearing sections and UT or RT on weld-free pressure sections as specified. A hydrostatic proof test of the housing pressure chamber, dimensional FAIR and PPAP come on request. |
Key features
- One-piece cast housing with integral cylinder, yoke slot and mounting feet removes several welds from a high-cycle load path.
- We model cast wall sections against the actuator torque and spring force from your calculation. The housing then does not distort under peak output.
- Moreover, we CNC bore and mill the cylinder bore and yoke guide slot in house. This keeps the piston travel parallel with the valve stem axis.
- ISO 5211 mounting flange and drive coupling are machined on the same setup, so the actuator bolts to the valve without an adapter plate.
- WCB gives a stiff, economical housing for standard plant air service; CF8M and 2205 duplex are used offshore and in corrosive atmospheres.
- Yoke, pins and wear plates are available in 17-4PH H900 or AISI 420 to resist wear at the sliding contact.
Applications
- Pneumatic scotch yoke actuators on ball, butterfly and plug valves for oil and gas pipelines.
- Hydraulic scotch yoke actuators for high-torque subsea and offshore valve actuation.
- Emergency shutdown valve actuators on chemical and petrochemical plants.
- Cryogenic LNG loading arms and tank farm valve automation using low-temperature CF8M.
- Water treatment and district heating valve automation on large diameter butterfly valves.
- HVAC and power plant isolation and control duty with spring-return fail-safe actuators.
Quality & compliance
Ningbo Ruican operates an IATF 16949 and ISO 9001 certified quality system. We trace each actuator housing to its casting heat, heat treatment batch and machining record. We supply material to ASTM A216 WCB, ASTM A351 CF8M or ASTM A995 4A, with solution annealing or normalising as applicable. Coupons from the same heat verify the mechanical properties. Magnetic particle and liquid penetrant inspection of load-bearing sections,
plus ultrasonic or radiographic examination where the drawing requires it, are available. The pressure chamber
can be hydrostatically proof tested with recorded results. Additionally, Ningbo Ruican does not hold PED or API monogram certification in its own name. We can still test and document to those standards per project, and we can arrange third-party witness inspection. EN 10204 3.1 certificates are standard, EN 10204 3.2 is available
on request, and PPAP or FAIR documentation can be provided for repeat production releases.
FAQs
Can you cast the housing with the cylinder and yoke slot in one piece?
Yes. That is the main reason customers use investment casting for this part. Additionally, we produce the cylinder, yoke guide slot, spring cartridge seat and mounting feet in a single casting. In general, that removes the welds that normally limit fatigue life in fabricated housings.
What actuator sizes can you produce?
We produce housings for scotch yoke actuators from small double-acting units for DN50 valves up to large
spring-return units for DN600 and above. Send the torque requirement and output rotation and we will confirm the
casting route and tooling approach.
Do you machine the ISO 5211 mounting interface?
Yes. The valve mounting flange, pilot diameter, bolt circle and drive coupling are machined to your drawing, along
with end flange faces, port threads and the position indicator boss.
How do you verify the housing will hold pressure?
The pressure chamber is hydrostatically proof tested at the pressure stated on the drawing, with holding time and
results recorded on the test report. Non-destructive examination and third-party witness can be added where the
project specification requires it.
Which material is best for offshore use?
CF8M is the standard choice for offshore atmospheres, and 2205 duplex is used where higher strength and chloride
pitting resistance are needed. WCB with a suitable coating system is common for onshore plant air actuators.
Can you supply the complete actuator housing kit?
Yes. We can supply the housing with a matched kit of yoke, guide pins, wear plates, spring cartridge seat and end covers. Every item in the kit is machined and heat treated, so your assembly line can build straight from the box.
