How to determine the cause of damage to a centrifugal slurry pump based on the wear pattern?

The slurry pump of the beneficiation plant will wear out due to erosion, abrasion, and corrosion. This will cause material loss on the surface of the components. Ultimately, the pump will be unable to operate due to perforation of the pump casing or severe decrease in pump head. The removed worn parts can provide a wealth of information about the pump's operating condition.

1. Operating point

The contour of the impeller blades can provide an indication of the average flow rate relative to the optimal efficiency flow rate. Uniform wear across the leading edge of the blades usually means that the pump is operating close to the optimal efficiency point. Running far below the optimal efficiency point will cause recirculation inside the impeller inlet. This can be proven by the vortex, which discharges the slurry from the front of the blade. These situations sometimes completely wear through the front cover plate of the impeller. Operating beyond the optimal efficiency point will result in higher inlet velocity and increased impact energy when solid particles collide with the impeller surface. However, large particles also have high energy due to their high quality. Therefore, the impact wear of the impeller rear cover plate may be caused by operating beyond the optimal efficiency point or by coarse particles.

2. Particle size

The two main mechanisms of wear on white iron components are impact wear and sliding wear. The definition of a sliding bed is a smooth, polished surface. Sometimes this surface forms a unique shape, like a sand dune; Some people believe that the wavelength of these sand dunes is related to the particle size of the slurry. As the particle size increases, coarse particles pass through this sliding bed and cause damage due to impact. This is a more destructive mechanism, where impact wear leads to faster material loss. The surface is no longer as smooth and may have a frosted appearance.

3. Corrosion

The material loss of components exposed to corrosive liquids and abrasive particles in slurry pumps is extremely high. The most obvious feature of severely corroded worn areas is their color. After oxidation, the martensitic matrix turns reddish brown, which weakens the matrix that supports hard carbides and is easily penetrated by abrasive particles, causing rapid wear.

Fortunately, by adding more alloying elements such as chromium or molybdenum to alter the chemical composition of the melt, the wear life of these components can usually be improved.

We believe that every detail is important, and the worn parts removed from the pump can provide a wealth of information about the pump's operating condition. With a little experience, one can determine the factors that cause the malfunction. If you want to try new materials or structures, it will be very helpful to you. The key is to maintain good records and discuss your concerns with the original equipment manufacturer of the pumping equipment.