FLOWSERVE Cast Iron Volute Casing – Casting Process, Inspection & Testing Guide
About Dongguan HydroBlue Co., Ltd.
DONGGUAN HydroBlue CO.,LTD. is a client-focused technical enterprise offering end-to-end solutions in fluid machinery, fluid engineering, industrial automation, and frequency conversion technologies. Our 8-person technical team covers fluid engineering, electrical engineering, and electronic engineering disciplines, enabling us to translate R&D capabilities into reliable commercial products. Alliances with Jiangsu University, Chinese Academy of Sciences, and Guangdong University of Technology strengthen our expertise in hydraulic systems, specialized coatings, and industrial control technologies.

Send us your pump model and volute casing requirements — our team will review and provide a competitive quotation within 24 hours.
OUR BRANDS & SERVICES
Our self-developed brand was founded to serve the fluid machinery and engineering sector with comprehensive technical solutions. Our ecosystem of proprietary technologies and product brands offers clients high-caliber technical consultation, sales support, and comprehensive product solutions — including pumps, frequency converters, servo drives, PLC-HMI, control cabinets, motors, mechanical seals and assemblies, couplings, gearboxes, and full-scope engineering services (overseas on-site 3D scanning reverse molding of pump replacement parts and equipment debugging by our engineers deployed internationally).
Casting Process
The volute casing casting process is selected based on geometry complexity, material requirements, and order quantity:
Investment Casting (Precision Casting)
Used for complex thin-walled geometries, stainless steel, and high-precision applications:
- Pattern Making — Wax patterns produced to exact casing geometry; runner and gating system designed for complete fill
- Cluster Assembly — Individual wax patterns attached to sprue to form a cluster; improves production efficiency
- Shell Building — Ceramic slurry dipped and sanded repeatedly to build a refractory shell around the wax cluster
- Dewaxing — Autoclave steam dewaxing removes wax; shell remains as the ceramic mould
- Mould Firing — Shell fired at high temperature for strength and dimensional stability
- Casting — Molten metal poured into the heated ceramic shell; precision solidifies against smooth ceramic face
- Post-Cleaning — Shell broken away; casting divested of runner, gate, and sprue
- Heat Treatment — Normalizing, annealing, or QT as required for the specified material and mechanical properties
- Inspection — Dimensional check, NDT, and material verification before release to machining
Sand Casting (Resin Sand)
Used for larger casings, cast iron, and cost-effective medium-volume production:
- Pattern Preparation — Wooden or metal pattern produced to casing geometry with allowance for shrinkage
- Mould Assembly — Cope and drag mould halves rammed with resin sand; core prints and venting prepared
- Coring — Sand cores placed to form internal cavities, volute passages, and bearing housing bores
- Casting — Mould assembled and metal poured; risers and feeders ensure complete fill
- Fettling — Mould material removed; risers, gates, and feeders cut off; sandblast cleaning
- Heat Treatment — Stress relief or normalizing for cast iron; QT for alloy steels
- Inspection — Full NDT and dimensional inspection before machining
Reverse Engineering Process
No original drawings? We reconstruct a dimensionally equivalent replacement:
- Submit worn sample or photographs with key dimensions marked
- FARO 3D laser scanning captures full internal and external geometry to ±0.05mm
- CAD model reconstruction from point cloud data; volute profile rebuilt to as-designed geometry
- CFD simulation validates hydraulic performance of the reconstructed volute passage
- Mould production and casting to the verified geometry
- CNC machining and full QC inspection before shipment
Surface Treatment
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Treatment
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Application
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Blacking
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Interior hydraulic passages — reduces surface roughness, minimizes friction losses
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Polishing
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Internal volute surfaces — smooth finish for clean water and low-solids applications
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Epoxy Coating
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Seawater and brackish water — barrier coating on interior surfaces
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Rubber Lining
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Abrasive slurry — vulcanized rubber bonded to interior; protects against particle erosion
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Chrome / Zinc / Nickel Plating
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Corrosion protection on exterior surfaces and flange faces
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Anodizing
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Aluminum casings — enhanced surface hardness and corrosion resistance
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Quality Testing & Inspection
Every volute casing undergoes comprehensive quality verification:
- Material Certificate — Mill certificate with chemical composition against ASTM, DIN, EN, ISO, TOCT
- Hydrostatic Pressure Test — 1.5× rated working pressure held for 30 minutes; no leakage or permanent deformation
- 3D CMM Dimensional Inspection — Full coordinate measurement of bearing housings, flange faces, and critical hydraulic geometry
- Non-Destructive Testing — RT and UT for internal casting soundness; MT and PT for surface and near-surface defects
- Hardness Testing — Verifies heat treatment condition and material grade compliance
- Surface Roughness Measurement — Interior volute surface roughness measured per ISO 1302
- Visual Inspection — Final check for surface defects, handling damage, and coating quality
Certifications: ISO9001:2015, ISO14001:2004, API Specification Q1.