FLYGT Impeller – Material Selection & Quality Assurance
About Dongguan HydroBlue Co., Ltd.
Dongguan HydroBlue Co., Ltd. supplies replacement impellers engineered for FLYGT submersible sewage pumps, covering the full range of impeller types including open, semi-open, closed, and vortex designs. Our team of eight engineers specialises in pump hydraulics, casting metallurgy, and precision machining, with research collaborations at Jiangsu University, Chinese Academy of Sciences, and Guangdong University of Technology. Beyond impellers, we supply complete pump spares, mechanical seal assemblies, motor control enclosures, and offer overseas field engineering support including 3D scanning of worn parts.
Send us your pump model and impeller specifications for a material recommendation and quotation.
Impeller Types for FLYGT Pumps
Selecting the correct impeller type is the first step in ensuring pump performance and service life. FLYGT submersible pumps use several impeller designs depending on the application:
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Impeller Type
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Solids Handling
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Efficiency
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Typical FLYGT Application
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Closed (shrouded)
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Small solids only (< 50 mm)
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Highest
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Clean water, drainage, high-head pumping
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Semi-open
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Moderate solids (50–75 mm)
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Medium
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Municipal sewage, fibrous media
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Open (non-clog)
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Large solids (> 75 mm)
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Medium
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Raw sewage, sludge, heavy debris
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Channel / vortex
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Very large or stringy solids
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Lower
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Wet-well solids handling, food processing waste
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Material Guide
The material choice directly affects impeller life in your specific media. We offer the following standard grades:
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Material
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Hardness
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Wear Resistance
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Corrosion Resistance
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Best For
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HT250 cast iron
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150–210 HB
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Standard
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Low
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General sewage, clean water, budget-friendly
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Hi-chrome (Cr ≥ 25%)
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500–650 HB
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Excellent
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Moderate
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Abrasive slurry, sand-laden water
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SS304 / SS316
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130–180 HB
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Low
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Good
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Corrosive effluent, food processing
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Duplex 2205
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230–290 HB
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Good
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Excellent
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Seawater, brine, high-chloride wastewater
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Quality Control & Testing
Every impeller we supply is produced under a documented quality plan covering the following stages:
- Material verification — Chemical composition analysis and mechanical property testing on each cast batch
- Dimensional inspection — CMM or gauge inspection of bore diameter, keyway, vane profile, and overall diameter. All measured against the approved CAD model
- Static balancing — Performed on all impellers; dynamic balancing available for high-speed or critical-service pumps
- Hardness testing — Brinell or Rockwell check on casting surface and core
- NDT — Dye penetrant (PT) on vane surfaces and hub area. Radiography (RT) or ultrasonic testing (UT) available on request for high-alloy castings
- Surface treatment — Rust-preventive oil coating, painting as specified, or custom coating for chemical-resistant applications
When to Replace the Impeller
Impeller wear is progressive and does not always cause immediate pump failure, but it reduces efficiency and increases energy consumption over time. The following indicators suggest replacement is needed:
- Pump head (discharge pressure) has dropped by more than 10% from the original performance curve at the same flow rate
- Vane edges are visibly rounded, pitted, or eroded, especially at the vane inlet and outlet edges
- Bearing or seal failures are occurring at shorter intervals, possibly due to impeller imbalance from uneven wear
- The impeller bore or keyway show signs of fretting or deformation, indicating the fit on the shaft has loosened
- Measured impeller diameter has reduced by more than 5% from the original due to wear on the vane OD
How to Order
- Identify your FLYGT pump model and impeller part number from the nameplate or maintenance records
- If the part number is unavailable, measure the impeller outer diameter, bore diameter, and keyway width, or send us the worn impeller for reverse-engineering
- Select the material grade based on the media type (abrasive, corrosive, or standard sewage)
- Specify any additional requirements: dynamic balancing, custom surface coating, NDT reports, or sample approval before batch production
- Submit your enquiry — standard impellers ship within 30 days; special materials or custom patterns 45–60 days
Frequently Asked Questions
Q1: What material do you recommend for standard municipal sewage?
HT250 cast iron is the most cost-effective choice for general sewage. For pumps handling abrasive sand or grit, upgrade to hi-chrome iron (500+ HB) which delivers 3–5 times longer wear life.
Q2: Can you match an existing impeller without drawings?
Yes. We reverse-engineer from a worn sample or high-quality photographs using FARO 3D laser scanning, and produce a CAD model for your approval before manufacturing.
Q3: Do you supply balanced impellers as standard?
Static balancing is standard on all impellers. Dynamic balancing (ISO 1940-1 G6.3 or G2.5) is available on request for high-speed pumps or critical installations.
Q4: What is the lead time for a duplex stainless steel impeller?
Duplex 2205 impellers require dedicated casting and heat treatment. Typical lead time is 45–60 days from deposit. Express service available with priority scheduling.
Q5: What warranty applies?
12 months from commissioning or 18 months from shipment. Covers material defects, dimensional non-conformance, and casting quality. Wear from abrasive media is application-dependent.
