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How Medium Composition, Concentration, and Temperature Affect Pump Material Selection

Release time：2026-03-09

When selecting a corrosion-resistant pump, simply knowing that the medium is “corrosive” is far from sufficient.

Key Medium Properties Affecting Pump Selection

When chemical pumps handle process fluids, factors such as medium composition, temperature, concentration, toxicity, solid content, and viscosity are critical for material selection.

Impact of Composition, Concentration and Temperature

Among these, composition, concentration, and temperature not only directly affect the corrosion resistance of materials, but also indirectly influence corrosion rate and mechanisms by changing the medium’s physical properties (such as viscosity, electrical conductivity, and chemical reactivity). These factors ultimately determine both the economic efficiency and operational safety of the selected materials.

Even for the same corrosive medium, differences in composition, concentration, or operating temperature can lead to completely different requirements for corrosion-resistant materials.

Example

Material Selection for H₂SO₄ at Different Concentrations and Temperatures:

Sulfuric Acid Concentration	Temperature Range	Recommended Materials
Dilute Sulfuric Acid (<20%)	Ambient – 50 °C	High-silicon cast iron, Alloy 20, Hastelloy, Fluoroplastic linin
Dilute Sulfuric Acid (<20%)	50 °C – 80 °C	High-silicon cast iron, Hastelloy,Fluoroplastic lining
Medium Concentration (20%–70%)	50 °C – 80 °C	High-silicon cast iron, 904L stainless steel, Alloy 20, Monel, Austenitic steel 2205, Fluoroplastic lining
Medium Concentration (20%–70%)	>80 °C	High-silicon cast iron, Alloy 20, Hastelloy
High Concentration (70%–98%)	Ambient – 80 °C	High-silicon cast iron, Carbon steel / Stainless steel (passivation film unstable), 904L stainless steel, 05 steel, Fluoroplastic lining
High Concentration (70%–98%)	>80 °C	High-silicon cast iron, Hastelloy, Alloy 20
Fuming Sulfuric Acid (Oleum)	Ambient – 50 °C	Fluoroplastic lining, Hastelloy, Alloy 20

Material Selection for NaOH at Different Concentrations and Temperatures:

Sodium Hydroxide Concentration	Temperature Range	Recommended Materials
Dilute Alkali (<20%)	Ambient – 50 °C	Carbon steel, 304L stainless steel
Dilute Alkali (<20%)	50 °C – Boiling point	304L stainless steel, 316L stainless steel
Medium Concentration (20%–50%)	Ambient – 90 °C	304L stainless steel, 316L stainless steel
High Concentration (>50%) and Molten Alkali	<90 °C	High-silicon cast iron, Alloy 20, Hastelloy
High Concentration (>50%) and Molten Alkali	High temperature (>90 °C)	High-silicon cast iron, Carbon steel / Stainless steel (passivation film unstable), 904L stainless steel, 05 steel, Fluoroplastic lining