Overview
A top-entry ball valve body is the pressure-containing shell that houses the ball, seats and stem of a floating or trunnion-mounted ball valve, assembled through a single bonnet opening from above. Because the geometry combines a spherical seat pocket, integral flange faces, a stuffing-box neck and often a trunnion boss, casting is the only economical route to near-net shape. CNC machining then brings the bore, seat pockets, flange bolt circles and gasket faces into tolerance. Ningbo Ruican produces these bodies by silica-sol investment casting in stainless and duplex grades, or by resin sand casting for larger carbon and low-temperature steel sizes, followed by heat treatment, full NDT and hydrostatic proof testing to the customer’s specified class.
Specification
| Parameter | Capability |
|---|---|
| Materials | CF8M / AISI 316, CF8 / 304, CF3M / 316L, duplex 2205, WCB carbon steel, LCB/LCC low-temperature carbon steel, ductile iron QT450-10 |
| Process | Silica-sol investment casting or water-glass investment casting; resin sand casting + CNC for large-bore carbon and low-temperature steel bodies |
| Dimensional tolerance | ISO 8062 CT5–CT7 (CT4–CT5 on machined features) |
| Size range | DN15–DN300 investment cast; DN300–DN600 resin sand cast |
| Pressure rating | Supplied to customer specification for ASME Class 150 / 300 / 600 / 900 and PN10–PN100 designs |
| NDT | RT and UT per ASTM E94 / E164 / A609; MT per ASTM E709; PT per ASTM E165 |
| Testing | Hydrostatic shell and seat-leakage testing, helium or air seat test on request, EN 12266-1 leakage rates as specified |
| Heat treatment | Solution annealing (stainless and duplex), normalising, or quench & temper (WCB/LCB/LCC) |
| Surface finish | Shot blast, pickling and passivation; Ra 3.2–6.3 µm as cast, Ra 1.6 µm or better on machined seats and gasket faces |
| Documentation | EN 10204 3.1 or 3.2, FAI and PPAP Level 3, PMI report, heat-to-part traceability |
Key features
- One-piece cast pressure boundary eliminates the body-to-bonnet weld seam and reduces leak paths.
- Near-net-shape spherical seat pocket and trunnion boss cut machining cycle time and tool wear.
- Integral RF, RTJ or FF flange faces machined complete with bolt circle, spot faces and serrated finish.
- Solution-annealed and pickled stainless gives consistent intergranular corrosion resistance across the section.
- Wall thickness verified by 100% UT survey on the pressure boundary, with records keyed to heat number.
- Machined on 4-axis and horizontal boring centres so bore, stem axis and flange faces stay coaxial within 0.05 mm.
Applications
- Oil and gas gathering, transmission and storage manifolds
- Moreover, Chemical and petrochemical process isolation duties
- Cryogenic and low-temperature LNG service in LCB/LCC grades
- Water treatment, desalination and slurry lines in duplex 2205
- Hygienic and general industrial utility skids
Quality & compliance
We produce every top-entry ball valve body under an IATF 16949-certified quality management system with controlled foundry practice, calibrated NDT and documented process validation. Material is released with EN 10204 3.1 certification, or EN 10204 3.2 when third-party witness is specified by the purchaser. Positive material identification (PMI) is performed on 100% of stainless and duplex heats and on a sampling plan agreed for carbon steel. Each body receives hydrostatic shell and seat-leakage testing, with charts and serialised reports retained. First article inspection (FAI) and PPAP Level 3 documentation packages are issued for new part numbers. Components are supplied to customer specification with full traceability from melt to finished part; we do not hold or claim an API monogram licence or a PED notified-body licence.
FAQ
What is the difference between a top-entry and a side-entry ball valve body?
A top-entry body is a single casting with one large bonnet opening on the vertical axis, so the ball and seats can be removed for maintenance without taking the valve out of the line. Moreover, a side-entry (split) body is made in two or three pieces bolted together. Top-entry bodies need a larger, more complex casting but give better structural integrity and fewer potential leak paths.
Which casting process do you use for a given size?
Silica-sol investment casting is used up to roughly DN300 where surface finish and CT5–CT6 accuracy matter most. Above that, resin sand casting plus full CNC machining is more economical for carbon steel WCB and low-temperature LCB/LCC bodies, and it avoids the pattern-cost burden of very large investment tooling.
Do you machine the seat pockets and stem bore, or supply rough castings?
Both are available. We regularly deliver fully machined bodies ready for assembly, including the spherical seat pocket, stem bore, stuffing-box face, flange bolt circles and RTJ grooves. Semi-finished bodies with machining allowance left on critical faces are also supplied for customers who prefer final fitting in-house.
Can you supply material to NACE MR0175 / ISO 15156?
Yes for the metallurgical condition. We cast and heat treat to the hardness and chemistry limits specified by the purchaser, and provide the test evidence. Also, formal compliance is declared by the valve manufacturer or end user; we supply to customer specification with full traceability.
Inspection and documentation
What lead time should we plan for?
Tooling and sample approval for a new investment-cast body typically runs 4–6 weeks, with production release after FAI and PPAP sign-off. Additionally, repeat orders are scheduled against agreed blanket releases. Contact Wendy She for a firm date against your drawing.
What file formats do you need for a quotation?
A 3D model (STEP or Parasolid) plus a 2D drawing with material, heat treatment, NDT extent, pressure class, testing requirements and surface specification. If you are re-sourcing an existing part, a sample or a reverse-engineered scan is enough to start.
