Submersible slurry pumps are designed for harsh environments and are used to handle abrasive and corrosive fluids. Choosing the right materials of construction is critical to their performance, durability and longevity as these pumps are required to withstand the rigors of mining, construction and wastewater treatment.

High-Chrome Alloy

High chromium alloy is a key material for submersible slurry pumps and is known for its excellent wear resistance. This alloy, sometimes referred to as high-chromium white iron or high-chromium iron, is particularly suitable for processing media containing abrasive solid particles, such as sand, ore and cinder. High chromium content (usually between 12% and 28%) can form a protective chromium oxide layer on its surface to enhance its wear resistance and corrosion resistance.

High-chromium alloys maintain excellent performance at high temperatures, a property that makes them popular in wear-resistant applications, not just slurry pumps. In the industrial field, high chromium alloys are widely used in various high-wear parts, such as crusher drums, silo linings and coal grinding roller sleeves. In submersible slurry pumps, high chromium alloys are mainly used for the wetted parts of the pump, such as impellers, casings and wear plates.

The flexibility of high-chromium alloys is that their properties can be tailored to meet the needs of specific applications by adjusting the carbon and chromium content. For example, increasing the chromium content can improve corrosion resistance, while adjusting the carbon content can affect the material's hardness and wear resistance. This flexibility allows manufacturers to optimize pump performance under varying industrial and mining conditions.

High chromium alloys used in submersible slurry pumps usually have the following typical compositions:

①27% chromium, 2.8% carbon: extremely wear-resistant.

②23% Chromium, 2.5% Carbon: Balanced wear resistance and impact resistance.

③15% chromium, 3.3% carbon: high hardness, medium corrosion resistance.

The microstructure of high-chromium alloys consists of hard carbides dispersed in a martensitic matrix. This structure gives them excellent resistance to wear and erosion, making them ideal for slurry applications.

Stainless Steel

Stainless steel is another important material commonly used in submersible slurry pump manufacturing, especially for components that require a balance of corrosion resistance and mechanical strength. Stainless steel forms a passivating chromium oxide layer that provides excellent corrosion resistance in a variety of environments.

The corrosion resistance of stainless steel allows submersible slurry pumps to operate reliably in a variety of environments, including those with high chloride content, acidic or alkaline pH, and high temperatures. This versatility makes stainless steel an ideal choice for pump components that come into contact with corrosive slurries or operate in corrosive environments.

Commonly used stainless steel grades used in submersible slurry pumps include:

1.Austenitic stainless steel (such as 304, 316): has good corrosion resistance and is often used in pump casings, shafts and other structural components. 316 stainless steel contains higher molybdenum and has enhanced resistance to pitting and crevice corrosion, making it suitable for harsher environments.

2.Duplex stainless steels (e.g. 2205, 2507): combine high strength with excellent corrosion resistance and are particularly suitable for components requiring mechanical strength and chemical resistance, such as pump shafts and impellers in demanding applications.

3.Super duplex stainless steel (such as 2507): has higher corrosion resistance and strength, suitable for the harshest mud environments.

When selecting a grade of stainless steel, factors such as the pH of the slurry, chloride content, temperature and the presence of other corrosive agents need to be considered. For example, in highly acidic mine drainage applications, high-alloy austenitic stainless steels or superduplex stainless steels may be selected for excellent corrosion resistance.

Stainless steel components in submersible slurry pumps often include:

①Pump shafts

②Fasteners and hardware

③Motor casing

④Sealing components

⑤Discharge connections

Stainless steel does have excellent corrosion resistance, however, in highly abrasive slurry environments, its wear resistance may be slightly inferior to that of high-chromium alloys. For this reason, pump designers often adopt a composite strategy: they tend to choose stainless steel for parts that are mainly subjected to corrosion, and prefer high-chromium alloys for parts that are prone to wear.

The application range of stainless steel in submersible slurry pumps is not limited to its corrosion resistance. In particular, the non-magnetic nature of austenitic stainless steel is a major advantage in certain specific applications, where magnetic fields may interfere with the operation of the pump or interact undesirably with surrounding equipment. In addition, the surface properties of stainless steel make it easy to clean and maintain, which plays a positive role in ensuring the overall hygiene of the pump system and extending its service life.

China Submersible Slurry Pump

Tianjin Kairun is a well-known company in the Chinese market, specializing in submersible slurry pumps made of high-chromium alloys and stainless steel, making full use of the unique advantages of each material.

For the wetted parts of the pumps, Tianjin Kairun chose high-chromium alloys to ensure excellent wear resistance when dealing with abrasive slurries. This material is particularly suitable in applications such as mining and dredging, where the pumped media often contains high concentrations of hard and abrasive particles. Tianjin Kairun can also optimize the performance of its pumps by adjusting the chromium and carbon content according to specific operating conditions, ensuring the service life of the pump is maximized.

For components that require high corrosion resistance, Tianjin Kairun uses a variety of grades of stainless steel. This material selection allows its pumps to operate stably in corrosive environments, such as in applications such as chemical processing or wastewater treatment. In addition, the use of stainless steel improves the overall durability of the pump and facilitates maintenance.

By combining high-chromium alloys and stainless steel in its submersible slurry pump design, Tianjin Kairun offers a product that resists both wear and corrosion. This dual-material approach gives the pumps the versatility to handle a variety of slurry types and operating conditions.

If you are selecting a submersible slurry pump manufacturer and would like to learn more about how material selection affects pump performance in a specific application, Tianjin Kairun welcomes your inquiry at catherine@kairunpump.com.

References:

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3. Toro, A., Sinatora, A., Tanaka, D. K., & Tschiptschin, A. P. (2001). Corrosion-erosion of nitrogen bearing martensitic stainless steels in seawater-quartz slurry. Wear, 251(1-12), 1257-1264.

4. Wilson, K. C., Addie, G. R., Sellgren, A., & Clift, R. (2006). Slurry Transport Using Centrifugal Pumps (3rd ed.). Springer.

5. Slurry Pumping Handbook (5th ed.). (2009). Warman International Ltd.