Material Selection and Design for Centrifugal Fans

Centrifugal fans operating under special conditions such as high temperatures and corrosion resistance benefit from extensive design and manufacturing expertise. Examples include high-temperature resistant centrifugal fans, corrosion-resistant centrifugal fans, explosion-proof fans, and wear-resistant fans. The materials used in these centrifugal fans must be selected based on their specific application requirements. The following outlines key considerations for material selection and design in centrifugal fans.

For centrifugal fans transporting high-temperature gases, the primary consideration is material creep at elevated temperatures, precluding the use of standard materials. When temperatures exceed 300°C, the mechanical properties of ordinary carbon steel deteriorate rapidly. Therefore, heat-resistant materials should be employed when the medium temperature surpasses 300°C. For temperatures exceeding 700°C, high-temperature alloy steels—specifically nickel and chromium steels—must be selected.

To prevent accidents, when conveying low concentrations of flammable or explosive gases, the fan casing may be constructed from steel plate while the impeller uses aluminum material. This configuration prevents sparks from igniting hazards during collisions or friction involving the aluminum impeller. However, when transporting relatively high levels of flammable or explosive gases, both the impeller and casing should be fabricated from aluminum.

If the centrifugal fan conveys media containing dust, sand particles, or particulate matter—such as coal dust, sand-ash mixtures, or similar materials—a dust collector must be installed before the fan inlet to reduce dust concentration below 150g/m³. Should dust removal prove inadequate or system design necessitate direct dust passage through the fan, a wear-resistant fan should be considered. Wear-resistant centrifugal fans primarily address blade wear issues.

To enhance blade durability, surface treatments such as carburizing, aluminum oxide spraying, or tungsten carbide welding can be applied to extend impeller lifespan. Corrosion-resistant centrifugal fans primarily handle corrosive substances like acids, alkalis, salts, and other corrosive chemical gases. The key consideration for these fans is material corrosion resistance. Common choices include ferrosilicon alloys, aluminum alloys, and ductile iron, with coating technologies also available.