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Purpose This paper aims to perform the solid particle erosion studies in simulated coal-fired boiler conditions with a view to compare the erosion behavior of two different types of detonation gun (D-Gun) sprayed cermet coating powders, that is, WC-12%Co and Cr3C2-25%NiCr on ASTM A36 steel and bare (uncoated) ASTM A36 steel. Design/methodology/approach Erosion studies were performed using an air jet erosion test rig at impingement angles of 45°, 60° and 90°. During the erosion studies weight loss, erosion rates in terms of volume loss (mm3/g) and measurement of erosion profiles were determined using optical profilometer. Findings Both cermet coatings had successfully protected the ASTM A36 steel from erosion at impingement angles of 45°, 60° and 90°. In the case of bare ASTM A36 steel, the erosion rates were maximal at an impingement angle of 45° and minimal at an impingement angle of 90°, thus depicting the peculiar erosion behavior of ductile materials. WC-12%Co coated specimens exhibited erosion behavior that is closer to the behavior of ductile materials. Cr3C2-25%NiCr coated specimens exhibited the maximum erosion rate at an impingement angle of 90° and minimum at an impingement angle of 45°, hence depicting the typical behavior of brittle materials. Practical implications It is expected that these results will contribute to the improvement of erosion resistance of induced draft fans, by the application of D-Gun sprayed WC-12%Co and Cr3C2-25%NiCr cermet coatings. Originality/value This paper evaluates the solid particle erosion behavior of bare and cermet-coated ASTM A36 steel which will be helpful in choosing the suitable cermet coating for induced draft fan applications.

Thermal spray coatings can be applied economically on machine parts to enhance their requisite surface properties like wear, corrosion, erosion resistance, and so forth. Detonation gun (D-Gun) thermal spray coatings can be applied on the surface of carbon steels to improve their wear resistance. In the present study, alloy powder cermet coatings WC-12% Co and Cr3C2-25% NiCr have been deposited on ASTM A36 steel with D-Gun thermal spray technique. Sliding wear behavior of uncoated ASTM A36 steel and D-Gun sprayed WC-12% Co and Cr3C2-25% NiCr coatings on base material is observed on a Pin-On-Disc Wear Tester. Sliding wear performance of WC-12% Co coating is found to be better than the Cr3C2-25% NiCr coating. Wear performance of both these cermet coatings is found to be better than uncoated ASTM A36 steel. Thermally sprayed WC-12% Co and Cr3C2-25% NiCr cermet coatings using D-Gun thermal spray technique is found to be very useful in improving the sliding wear resistance of ASTM A36 steel.

Abstract-Hardfacing is a surface alteration method mostly utilized for the deposition of superior and hard materials on the surface of a substrate with the help of some suitable welding process. This technique is generally used for improving the desirable surface characteristics, for example, erosion resistance, corrosion resistance, etc. of several engineering parts. In the present investigation three dissimilar Fe-C-Cr based hardfacing electrodes were deposited on the surface of ASTM A36 steel by using manual metal arc welding process for improving its wear resistance. Sliding wear behavior of bare ASTM A36 steel specimens and hardfaced ASTM A36 steel samples was studied on a pin-on-disc wear tester. It was observed that the sliding wear behavior and performance of all the hardfaced specimens was observed to be superior to that of bare ASTM A36 steel samples. The effect of the different hardfacings on the wear characteristics, behavior, performance and the extent of wear on ASTM A36 steel were thoroughly examined. The impact of the diverse hardfacing alloys on the wear characteristics, behavior, performance and the degree of wear on ASTM A36 steel were thoroughly examined.The effect of varying the percentage composition of chromium from 23% to 33% and carbon from 3.5% to 4.5% in the diverse Fe-C-Cr based hardfacing electrodes on the resultant microstructure and also the wear behavior of the deposited layers was studied. The comparison of cumulative wear rate (in Bowden) of all the hardfaced specimens with that of the bare ASTM A36 samples exhibited a considerable advancement in the wear resistance imparted by Fe-C-Cr based hardfacings over the ASTM A36 steel. Keyword -Cumulative Wear Rate (CWR), Hardfacing, Manual Metal Arc Welding (MMAW), Pin-on-Disc Wear Tester. I.INTRODUCTION The economic condition of individuals and industry is significantly affected by losses due to wear, hence they tend to focus on the causes of wear and methods that can improve wear resistance. All types of industries such as manufacturing, assembly, construction, automobiles, etc. face the problem of wear on components in service. Due to wear the components need frequent repair and replacement, which costs money and causes downtime of the equipment. Degradation of materials due to wear ultimately results in very high losses that affects the economic situation of all the countries as well as defames their reputation [1]. Erosive wear has been a persistent problem faced by boiler components such as boiler tubes, super-heater tubes and blades of induced draft fans, etc. especially in coal fired power plants.Commonly used surface alteration method is hardfacing in which hard and superior materials is meld onthe surface of the inferior base material by welding for improving its wear resistance [2]. Wear is the degradation of material from either of two surfaces in contact due to relative motion between them [3].Wear is generally a very slow process, but it goes on very steadily and continuously [4].Although due consideration has been paid b...

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