Pump Body Materials

Common materials for pumps include: cast iron, cast steel, stainless steel, carbon structural steel, alloy steel, and non-metallic materials.

I. Cast Iron

Gray Cast Iron

The most commonly used cast iron, with a GB code of HT. Typically used for pump bodies, impellers, covers, and suspensions in clean water pumps. Common grades: HT150, HT200, HT250.

HT150 for non-critical parts (bases, pads); HT200 for pump bodies, covers, and suspensions; HT250 for impellers, wearing rings, and shaft sleeves.

International designations: FC (Japan), GG (Germany), Class (US).

Ductile Iron

A high-performance cast iron (GB code QT) with mechanical properties close to steel and better casting/machining performance than steel, often used as a substitute for cast steel.

Common grades: QT450-10, QT500-7, QT600-3. Widely used for pump impellers (especially cut-type open impellers) due to cost-effectiveness.

International designations: GGG (DIN), Ductile iron (US).

Other types: Corrosion-resistant cast iron (high-silicon iron), wear-resistant cast iron (white iron), and malleable iron (high-toughness). Their use in pumps is limited due to machining challenges.

II. Cast Steel

Used for pressure parts when system pressure > 1.6 MPa due to its high strength. GB code: ZG, with the most common grade being ZG230-450.

International designations: CS (Japan/US).

III. Stainless Steel

Austenitic Stainless Steel

The most widely used in pumps, e.g., 0Cr18Ni9, 1Cr18Ni9Ti, 0Cr18Ni12Mo2Ti. Excellent corrosion resistance (except for hydrochloric acid, dilute sulfuric acid, etc.), making it ideal for chemical pumps.

International designations: SS304, SS316, SS316L (Japan/US).

Martensitic Stainless Steel

e.g., 2Cr13, 3Cr13, with better mechanical properties than austenitic grades. Commonly used for pump shafts and sleeves.

International designation: SS420 (Japan/US).

Other options: High-alloy stainless steel (Alloy 20) and duplex stainless steel for severe corrosion environments.

IV. Carbon Structural Steel

Plain Carbon Structural Steel: Represented by Q235, used for steel plates and sections.

High-Quality Carbon Steel: Represented by 45# steel, widely used for pump shafts in non-corrosive applications.

V. Alloy Steel

Represented by 40Cr, used for high-strength pump shafts.

VI. Non-Metallic Materials

Primarily used for sealing components:

Polytetrafluoroethylene (PTFE): Ideal for chemical pump gaskets and mechanical seal static seals due to excellent corrosion/heat resistance (up to 250°C). Drawbacks: high hardness and difficult assembly.

Fluororubber: Good heat/corrosion resistance (up to 160°C), recommended for chemical pump seals unless specified otherwise.

Nitrile Butadiene Rubber (NBR): Used for oil-resistant or clean water static seals.

Note: Material selection should align with medium properties, operating pressure, temperature, and corrosion requirements to ensure optimal pump performance and longevity.