Views: 0 Author: Site Editor Publish Time: 2025-08-20 Origin: Site
Property | Cast Iron | Brass | Stainless Steel |
Cost | Lowest (≈$2/kg) | Medium (≈$6/kg) | Highest (≈$3.5/kg, 304 SS) |
Corrosion Resistance | Poor(requires epoxy coating) | Moderate(fresh water/weak acid) | Excellent(seawater/strong acids) |
Media Compatibility | Water, oil (pH 6-8) | Potable water, mild liquids | Chemicals,seawater,chlorinated solutions |
Pressure Rating | ≤1.6MPa | ≤2.5MPa | ≥10MPa |
Temp. Range | -20℃~120℃ | -50℃~200℃ | -196℃~400℃ (316L) |
Hygienic Class | Low (rough surface) | Food-grade (antibacterial) | Medical-grade (Ra≤0.8μm) |
Applications | Agricultural pumps, HVAC | Domestic boosters,ship freshwater | Pharma, desalination, nuclear |
Key Technical Insights
1. Cast Iron
Pro: 1/3 cost of stainless, vibration damping (noise -15dB)
Con: Electrochemical corrosion in seawater (>0.5mm/year loss)
Upgrade: Ductile iron QT500-7 (500MPa strength) for fire pumps
2. Brass
Core Value: Natural antibacterial (kills 99.9% E. coli)
Limit: Dezincification in hard water (>180mg/L CaCO₃)
Premium: Naval brass (+0.5% Sn) triples seawater resistance
3. Stainless Steel
Tech Highlights:
304 SS: Resists 10% nitric acid
316L SS: Molybdenum-added, PREN≥35
Duplex 2205: 550MPa yield strength
Surface: Electropolished to Ra≤0.4μm (FDA compliant)
