Mixed-flow Pump Body: Materials, Characteristics, and Applications

1. Common Materials for Mixed-flow Pump Bodies

Mixed-flow pumps combine features of centrifugal and axial-flow pumps, suitable for medium flow rates and heads. Pump body materials are selected based on medium properties, corrosion resistance, and wear resistance.

2. Key Factors Influencing Material Selection

(1) Medium Characteristics

Corrosion: For seawater or acidic solutions, stainless steel (316L) or nickel-based alloys are preferred.

Abrasion: High-chromium alloys or rubber linings suit media with high solid content (e.g., river silt, mineral particles).

Temperature & Pressure: High-temperature applications (e.g., thermal power plants) require heat-resistant alloys like Inconel.

(2) Operational Conditions

Flow Rate & Head: Higher flow rates may increase erosion, necessitating wear-resistant materials.

Cavitation Risk: Pump bodies in cavitation-prone areas (e.g., impeller inlets) benefit from materials with high impact resistance (e.g., Hastelloy C).

(3) Cost & Maintenance

Cast iron is cost-effective for low-corrosion, low-wear scenarios, while high-chromium alloys or plastics are pricier but reduce downtime in harsh conditions.

3. Structural Design for Wear & Corrosion Resistance

Wear-Resistant Linings: Replaceable liners (e.g., high-chromium cast iron or rubber) in pump bodies extend service life.

Flow Channel Optimization: Smooth, streamlined designs minimize turbulence and erosion (e.g., spiral volute structures).

Surface Treatment: Coatings like ceramic or Stellite welds enhance surface hardness and corrosion resistance.

4. Application Cases

Irrigation & Drainage:

Pump bodies in agricultural water systems often use cast iron or ductile iron for cost efficiency.

Mining & Dredging:

High-chromium alloy pump bodies resist abrasion from sand and ore particles in slurry transport.

Chemical Industry:

Stainless steel (316L) or PTFE-lined pump bodies handle corrosive chemicals like sulfuric acid or chlorides.

Marine Engineering:

Nickel-based alloys or duplex stainless steel (e.g., 2205) withstand seawater corrosion in shipboard systems.

5. Performance Impacts of Material Selection

Efficiency: Smooth surfaces (e.g., polished stainless steel) reduce fluid resistance, improving hydraulic efficiency.

Reliability: Wear-resistant materials maintain flow channel dimensions, preventing performance degradation (e.g., head loss due to erosion).

Service Life: Corrosion-resistant materials like Hastelloy C can extend pump life by 3–5 times compared to cast iron in harsh environments.