The volute casing body is what turns impeller velocity into usable pressure, so its internal profile, surface finish and wall integrity decide pump efficiency, suction behaviour and service life. Ningbo Ruican investment casts the casing in stainless or duplex steel and finish-machines the suction flange, discharge, wear-ring seats and seal faces to your print, giving a smooth, dimensionally repeatable waterway that passes hydrostatic and performance testing without hand fettling.
Specifications
| Item | Specification |
|---|---|
| Casting process | Silica sol lost-wax investment casting with ceramic-cored internal waterway |
| Material options | Stainless 304 / CF8, 316 / CF8M, duplex 2205, super duplex 2507, nickel aluminium bronze |
| Dimensional tolerance (ISO 8062-3 CT grade) | CT5-CT6 as-cast, CT4 on machined flanges, wear-ring seats and seal bores |
| Machining | Horizontal boring and 4-axis VMC; suction and discharge flanges, wear-ring seats, seal chamber and foot machined |
| Surface finish (Ra) | Ra 3.2 um as-cast waterway, Ra 1.6 um on flanges, Ra 0.8 um on seal and wear-ring bores |
| Weight range | 6.0 kg – 28.0 kg per casing |
| Typical lead time | Tooling 30-40 days, samples 18 days after tooling, production 35-45 days |
Key features
- Ceramic-cored volute waterway cast near net shape, holding the hydraulic profile and wall thickness consistently.
- Smooth as-cast internal surface reduces friction loss and helps the pump hit its rated duty point.
- Wear-ring seats and seal chamber machined concentric to the shaft axis within 0.05 mm TIR.
- Flange faces and bolt circles machined to ISO or ANSI drilling patterns for drop-in pump assembly.
- Solution annealed and passivated, with 100% dye penetrant inspection and hydrostatic pressure testing.
- Optional pressure test to 1.5 times design pressure with certified test reports per serial number.
Applications
- Municipal and industrial fire engine centrifugal pumps
- Airport rescue and firefighting vehicle pump modules
- Wildland and brush-fire skid units on light 4×4 chassis
- Rescue and emergency support vehicles with auxiliary water pumps
- Marine fire-fighting and dockside monitor pump sets
- Stationary foam proportioning and booster pump skids
Quality & compliance
Ningbo Ruican produces fire pump volute casing bodies under IATF 16949 discipline with APQP from feasibility to PPAP level 3 or 4. Documentation includes EN 10204 3.1 material certification with heat and solution-anneal records, ferrite and intergranular corrosion checks on stainless grades, 100% dye penetrant inspection, radiographic testing of critical sections where specified, and full dimensional reports with capability data on wear-ring seats and seal bores. Hydrostatic proof testing, salt-spray exposure to ISO 9227 and pump performance validation against your duty curve are available on request before production release.
FAQ
Which stainless grade should I choose for a fire pump casing?
CF8M (316) is the standard choice for municipal and airport pumps because it handles foam concentrate and brackish water well. For seawater dockside or marine service we recommend duplex 2205 or super duplex 2507 for much better pitting and chloride stress-corrosion resistance, and nickel aluminium bronze where cavitation resistance matters most.
Can you cast the internal volute passage without a core assembly?
Yes. We use ceramic cores to form the internal waterway in one piece, which avoids the core-shift and finning that appears with sand-cored volutes. The result is a smooth, dimensionally repeatable passage that needs minimal grinding and helps your pump meet its rated flow and head without rework.
What pressure testing do you perform?
We hydrostatically test each casing to 1.5 times design pressure, hold for the duration your specification requires, and record the result against the casting serial number. Certified test reports ship with the batch, and we can witness third-party inspection or run performance testing against your duty curve on request.
How do you control corrosion in stainless castings?
Every stainless casing is solution annealed, quenched and passivated, then verified by ferrite measurement and intergranular corrosion testing on sample coupons from the heat lot. We hold the anneal chart and passivation record in the PPAP package so your end customer has full metallurgical traceability.
Do you machine the casing complete for assembly?
We deliver the casing fully machined: suction and discharge flanges, wear-ring seats, seal chamber bore, drain and gauge ports, and mounting feet. If you prefer, we can leave the wear-ring seats with finish allowance so you can line-bore the casing to match your impeller after assembly.
CTA
Send your fire pump volute casing drawing, material grade, duty point and test specification to Ningbo Ruican for a build-to-print quotation and tooling proposal. Contact Wendy She — sales@cnsandcasting.com — WhatsApp +86-13777124360 for RFQ support, sample status or APQP documentation.
