Overall, this section covers swing check valve disc arm casting. It also covers investment cast valve trim CF8M 316L. It also covers check valve hinge arm manufacturer.
Specifications
| Parameter | Detail |
|---|---|
| Material | ASTM A351 CF8M (316L equivalent) and CF8 (304 equivalent), ASTM A216 WCB carbon steel, ASTM A995 4A / 2205 duplex; 17-4PH H900 or H1025 for hinge pins and disc studs |
| Process | Silica sol lost wax investment casting, the standard route for small-to-medium pressure-boundary trim |
| Dimensional tolerance | ISO 8062 CT4 to CT6 as cast, with hinge bore, disc face and stop lug machined to drawing tolerances |
| Surface finish | As-cast Ra 3.2 to 6.3 micrometres; machined hinge bore and sealing face Ra 1.6 to 3.2 micrometres, electropolishing available |
| Machining | CNC milling and turning of the hinge lug bore, disc seat face, hinge pin holes and stop faces; boring and reaming of the pivot bore for the hinge pin |
| Pressure class | Designed for ASME class 150 to class 600 swing check valves per ASME B16.34 |
| 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 cast surfaces and RT on critical sections. Dimensional FAIR and seat leakage testing of the assembled valve to API 598 or ISO 5208 come on request. |
Key features
- Lost wax casting produces the arm profile, hinge lugs and rib sections in one piece, so there is no weld between the arm and the hinge boss to fail in service.
- Hinge bore and pin holes are machined in-house, keeping the pivot axis square to the disc face so the disc seats evenly instead of cocking.
- CF8M and 2205 duplex grades give pitting and crevice corrosion resistance in seawater, brine and chemical service; WCB is used for steam and clean water.
- Optional 17-4PH H900 hinge pins and disc studs deliver high strength and galling resistance at the pivot, the highest wearing point of the assembly.
- Moreover, Balanced arm geometry is developed from your drawing or from a reverse engineered sample, with weight and centre of gravity held consistent across the batch.
- Near-net shape with 1 to 2 mm of machining stock reduces material removal, cycle time and total cost per piece compared with a fabricated assembly.
Applications
- Water and wastewater pump discharge lines where a non-slam swing check disc protects the pump.
- Steam condensate return headers and boiler feed lines in power and heating plants.
- Oil and gas production manifolds, export lines and pipeline check service (CF8M or 2205 duplex).
- Generally, Chemical process lines carrying corrosive liquids, solvents and acids.
- Slurry and mining tailings lines where a hardfaced disc face and a heavy section arm resist abrasion.
- Cryogenic LNG and industrial gas service with impact-tested CF8M material and low-temperature seat design.
Quality & compliance
Ningbo Ruican runs an IATF 16949 and ISO 9001 certified quality system, and every disc arm is traceable to its
casting heat number, melt record and heat treatment batch. Additionally, we supply material to ASTM A351 CF8M, ASTM A351 CF8, ASTM A216 WCB or ASTM A995 4A. Solution annealing or normalising runs in house. In general, mechanical properties are verified on test coupons that accompany each lot. Also, surface and volumetric NDT covers magnetic particle, liquid penetrant, ultrasonic and radiographic examination. In addition, we hydrostatically test assembled valves, with seat leakage acceptance to API 598 or ISO 5208.
Ningbo Ruican does not claim PED or API monogram
certification in its own name; testing and documentation to those standards is available per project and
third-party witness inspection can be arranged. EN 10204 3.1 certificates are issued as standard, EN 10204 3.2 on
request, and PPAP or FAIR documentation packages can be supplied for serial production programmes.
FAQs
What is the difference between the disc arm and the disc?
Moreover, the disc is the sealing element that closes against the seat. The disc arm, sometimes called the hinge arm or
clapper arm, carries the disc and pivots on the hinge pin. We cast and machine both, plus the hinge pin in 17-4PH,
so the whole swing assembly can be supplied as a matched set.
Can you match the arm geometry of an existing valve design?
Yes. Send the drawing, or send a sample part and we will 3D scan it and rebuild a manufacturing model. Existing
hinge pin diameter, disc bolt circle and stop face position are held so the arm drops into your current valve
without redesign.
Which grade is best for seawater duty?
ASTM A995 4A (2205 duplex) is the preferred choice for seawater and high-chloride service because of its pitting
resistance and higher mechanical strength. CF8M is the common alternative where the chloride content and
temperature are moderate.
How do you control the hinge bore alignment?
The hinge lug bore and the disc mounting face are machined in a single fixtured setup on a CNC machining centre,
using datums taken from the casting as agreed at the tooling stage. Bore perpendicularity and position are checked
on the first article and on a sampling plan during production.
Do you supply hinge pins and fasteners as well?
Yes. Hinge pins, disc studs and nuts are usually produced in 17-4PH to H900 or H1025 condition, or in 316L for
corrosive service. Generally, we can supply them machined, heat treated and passivated as part of the same order.
What is the typical lead time for a new part?
Tooling for a silica sol lost wax disc arm is normally completed in three to five weeks, followed by first-article
castings and machining for approval. Repeat production runs follow after first-article acceptance, with scheduling
agreed per release quantity.
