Views: 0 Author: Site Editor Publish Time: 2025-08-03 Origin: Site
Property | Brass | Stainless Steel | PPO Plastic |
Density(g/cm³) | 8.4 | 7.9 | 1.06 |
Tensile Strength(MPa) | 250-400 | 520-800 (316L) | 65-85 (120 w/ glass fiber) |
Max Temp(℃) | 200 | 400 (316L) | 110 (peak 130) |
Corrosion Res | Weak in S/NH₃ media | Excellent (PREN≥35) | Resists all acids |
Cost | ★★★☆☆ (≈$21/kg) | ★★★★☆ (≈$6.3/kg) | ★★☆☆☆ (≈$11/kg) |
Max Velocity(m/s) | 45 | 65 | 28 |
Cavitation Res | Poor (NPSHr≥3m) | Good (NPSHr≥2m) | Excellent (NPSHr≤1m) |
Applications | Domestic water, ship FW | Chemical pumps, seawater | Electrolyte transfer, pure water |
Technical Insights
1. Brass Impeller
Pros:
Antibacterial (99% Legionella kill rate)
High thermal conductivity (109W/m·K)
Cons:
Dezincification: When Cl⁻>100ppm & flow<1.5m/s
Stress corrosion: Fails in NH₃-N (>50ppm)
2. Stainless Steel Impeller
Key Tech:
Laser welding: G2.5 balance grade
Surface treatment:
Electropolishing (Ra≤0.2μm)
Low-temp nitriding (HV≥1000)
Material Selection:
304 SS: Cl⁻<200ppm
316L SS: Cl⁻<10000ppm
Duplex 2205: High strength + corrosion resistance
3. PPO Impeller
Advantages:
Zero metal contamination (ultra-pure water)
Cavitation energy absorption
70% weight reduction → 40% lower start current
Enhancements:
20% glass fiber: Flexural strength→120MPa
Conductive carbon fiber: Anti-static (10⁶Ω)
Limitations:
Max temp 110℃
Dissolves in benzene/halogen solvents
