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Pump Material Selection Comparison: 304 Stainless Steel vs 316 Stainless Steel vs Cast Iron
Published Time:
2026-07-31
The material of pump wetted parts directly determines the service life and operational reliability of the equipment. Below is a performance comparison and application recommendation of three mainstream pump materials for systematic selection reference.
The material of pump wetted parts directly determines the service life and operational reliability of the equipment. Below is a performance comparison and application recommendation of three mainstream pump materials for systematic selection reference.
1. Cast Iron (HT200 / HT250)
As the most traditional and widely used pump material, cast iron features excellent compressive strength, good vibration damping performance, low cost and mature processing technology. However, it has poor corrosion resistance and is prone to rust and erosion caused by dissolved oxygen and chloride ions in water. It is suitable for neutral or weakly corrosive clean water with a pH value of 6~8. Typical applications include normal-temperature non-corrosive working conditions such as clean water delivery, circulating water systems, fire water supply and air-conditioning cooling water.
2. 304 Stainless Steel (06Cr19Ni10)
304 is a classic austenitic stainless steel containing approximately 18% chromium and 8% nickel. It delivers superior atmospheric and fresh water corrosion resistance and better oxidation resistance than cast iron, with excellent tolerance to nitric acid, alkaline solutions and most organic acids. It is not applicable for media with high chloride ion concentration such as seawater and saline groundwater. Pitting and crevice corrosion risks occur when the chloride ion concentration exceeds 200mg/L. It is ideal for drinking water, food processing, pharmaceutical sanitation and weakly corrosive chemical media.
3. 316 Stainless Steel (06Cr17Ni12Mo2)
Based on 304 stainless steel, 316 stainless steel is added with 2%~3% molybdenum (Mo), which greatly enhances its resistance to chloride pitting corrosion, with the critical pitting temperature about 20℃ higher than that of 304. It exhibits outstanding corrosion resistance against sulfuric acid, hydrochloric acid, acetic acid and seawater, making it the preferred material for harsh working conditions with salt, chloride and strong acid-base substances. It is widely used in seawater lifting, chemical processes, pharmaceutical production, marine engineering and high-temperature corrosive environments.
4. Corrosive Working Condition Selection Guide
Medium Type | Recommended Material | Typical Application |
|---|---|---|
Clean water, tap water, river & lake water | Cast Iron / 304 Stainless Steel | Agricultural irrigation, domestic water supply |
Weak acid & alkaline water, low-chloride industrial water | 304 Stainless Steel | Food & beverage industry, pharmaceutical pure water system |
Seawater, saline groundwater, high-chloride media | 316 Stainless Steel | Seawater desalination, coastal engineering |
Strong acid & alkaline, high-temperature corrosive media | 316L / Engineering Plastic | Chemical industry, smelting, electroplating |
Material selection requires comprehensive consideration of medium composition, temperature, concentration and actual operating conditions. Reasonable selection avoids over-specification cost waste and premature equipment failure caused by improper material matching.
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