Slurry and dry particle erosion wear properties of WC-10Co4Cr and Cr3C2-25NiCr hardmetal coatings deposited by HVOF and HVAF spray processes

Thermally sprayed hardmetal coatings were produced to provide improved erosion wear compared to conventional cast GX4CrNi13-4 martensitic steel (CA6NM) used in hydro turbine components. Sprayed coatings and reference materials were tested with high-speed slurry pot tester using either fine or coarse quartz as the erosive media. Additional erosion tests were carried out with centrifugal dry erosion tester. Tungsten carbide based coatings provided the highest wear resistance due to the high hardness and even distribution of the fine carbide particles. The cast 13-4 steel samples experienced up to 180 times higher wear rates in fine quartz slurry and up to 36 times higher wear rates in coarse slurry compared to the sprayed coatings.

The Corrosion Erossion of Ship Propeller Al 7075 Produced by Gravity Sand Casting

Propeller is one of the important components of ships and boats that function as motor or boat propulsion. The mechanical properties required in propeller material are high toughness, easy to cast, and good engine capability, as well as good resistance to corrosion and erosion. One of the aluminum alloys that have been widely used in major vessels in propeller systems is the Nickel-aluminum-bronze (NAB) alloy because it has an excellent combination of mechanical properties and corrosion-erosion resistance. Another type of aluminum alloy that is widely used as a machining component is the Al 7075 T651 because it has the highest strength among other aluminum alloys. The mechanical properties of the Al 7075 T651 are directly proportional to the erosion resistance of the propeller which agrees with the pot tester porridge. The higher the value of the erosion propeller failure that occurs also increases with increasing testing rotational speed. For corrosion, a propeller with air testing media at a speed of 1000 rpm which results in significant corrosion products. Keywords: Al 7075 T651, Slurry Pot Tester, Corrosion Erosion

Study on role of particle shape in erosion wear of austenitic steel using image processing analysis technique

Properties of flowing media (e.g. such as fly ash, bottom ash, coal, mineral tailings, sand slurries, etc.) play a crucial role in the service life of centrifugal slurry pump components. Generally, these solid particles vary in shape and size. In literature, a limited number of studies have been carried out to investigate the influence of particle size and shape on erosion wear. Stainless steel (SS 316L) is the most commonly used material for the fabrication of slurry pump components namely, casing, impeller, shafts, and sealing columns. In the present study, the influence of particle type and circularity factor on erosion wear of austenitic steel has been studied. A slurry pot tester (Ducom TR-41) was used to perform the experiments that established the erosion wear of slurry pump austenitic steel under the influence of the parameters noted above. Abrasives used in the current study are fly ash, bottom ash, and sand. Surface smoothness, circularity factor, coefficient of variance, sphericity, and solidity of solid particles were also analyzed prior to performing the experiments. The circularity factor value and erosion wear rate hold a power law relationship. Three-dimensional surface plots were plotted to explain the underlying mechanism of erosion wear.

Cavitation and Slurry Erosion of Aluminum in the Slurry Pot Tester

In harnessing clean and renewable energy sources water turbines represent a significant portion of the power generation worldwide. Because of erosion, repair and maintenance of hydraulic turbines is a difficult problem. Material removal in hydraulic turbine components may occur either by particle erosion or cavitation erosion or by their combined action. Many ASTM standard and non standard test rigs are aimed at specific tests, like solid particle erosion, cavitation erosion. To simulate the real conditions in a laboratory setup, a novel method is employed to combine the effect of cavitation erosion and slurry erosion in the slurry pot tester. Triangular prismatic cavitation inducers are used in the conventional slurry pot tester. The aluminum test specimens are investigated in the slurry pot tester. A wide variation in material loss was noted under different exposure conditions. The maximum material loss is ascribed to combined effects of solid particle erosion and cavitation erosion.

Erosive Wear Performance and Mechanism of Engineering Ceramic Materials

A slurry pot tester was used to evaluate the erosion behavior of alumina (Al2O3), zirconia toughened alumina (ZTA), and silicon nitride ceramics. The eroded surface of sample was studied by scanning electronic microscope and the primary erosion wear mechanisms for ceramic materials were analyzed. On the same experimental condition, erosion wear resistance of materials follows this rule: Si3N4>ZTA>Al2O3. The key factor affecting erosive wear performance of ceramics is their microstructure. The primary erosive wear mechanisms for Al2O3, ZTA and Si3N4 ceramics are lateral crack propagation, whole grains pulled out and plastic deformation. The erosive wear performance of Si3N4 ceramic is the best in this experiment, due to their microstructure morphology with elongated grains.

Study on Erosive Wear and Novel Wear-Resistant Materials for Centrifugal Slurry Pumps

The erosive wear of the impellers and liner of centrifugal slurry pumps was investigated. The eroded material surfaces of different parts in impellers and liner have been studied by using scanning electron microscopic (SEM). The examination shows that the eroded surface pattern and eroded degree of different parts in slurry pump are different. The microstructure SEM analysis provides insights into the erosive wear mechanisms in pumps. The material removal processes include chipping out of lateral cracks caused by impact of the erodent particles, grain boundary cracking and grain pull out, as well as plastic deformation caused by the repeated sliding and impact of the particles. A new kind of anti-erosive wear material- Al2O3 engineering ceramic has been made. Engineering ceramics have a high application potential for wear-protection of different working parts used for slurry pumps and mineral industries. Measurements of the erosive wear of various materials used in centrifugal slurry pumps have been studied in a simple slurry pot tester in aqueous slurry of silicon carbide grits. Effects of varying the size distribution and volume content of erodent particle are investigated.