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Material damage caused by the attack of particles entrained in a fluid system impacting on a surface at a high speed is called 'erosive abrasive wear'. Carbon steels are the most common ones used in the fabrication and construction of boilers and furnaces. Typical erosive abrasive wear situations encountered in boilers are caused by the impact of hard particles such as ash and clinker entrained in flue gases. These situations can lead to serious damage. Engineering components encountering erosive abrasive wear conditions during operation can be improved by hardfacing with a wear resistant material. In this paper an attempt has been made to analyse in detail the effects of different experimental parameters such as specimen temperature, standoff distance, orifice diameter, air pressure and abrasive particle size on the erosive abrasive wear behaviour of cobalt based alloy (stellite) surface produced by plasma transferred arc hardfacing process. It is found that air pressure caused a predominant effect on the wear rate of a hardfaced surface, compared to other variables. Both experimental and statistical investigations show that the wear resistance of the cobalt based alloy (stellite) surface is four times better than that of the substrate (carbon steel).

Abrasive slurry wear is generally defined as a mechanical interaction in which the material becomes lost in a surface that is in contact with moving particles, such as laden liquid. Slurry wear abrasion occurs in extruders, slurry pumps, and pipes that carry the slurry of minerals and ores in mineral processing industries. The life of the components used under slurry abrasion conditions is governed by the process parameters, the properties of the abrasive particles in the slurry, and the material properties. This paper analyses in detail the effects of operating variables, such as abrasive particle size, slurry concentration, speed of rotation, and slurry bath temperature, on the abrasive slurry wear behavior of a iron based alloy (stainless steel), cobalt based alloy (stellite), and nickel based alloy (colmonoy) surfaces produced by a Plasma Transferred Arc (PTA) hardfacing process. Of the four variables considered in this investigation, it was found that the slurry concentration had a predominant effect on the wear rate of hardfaced surfaces compared to the other variables. Microstructural analyses of the worned surfaces were carried out using SEM. Both the experimental and mathematical investigations showed that the wear resistance of an iron based alloy was 4 times better than the base metal. Similarly, the cobalt based alloy exhibited a 3 times higher wear resistance while the nickel based alloy showed a 2 times higher wear resistance compared to the base metal (carbon steel).

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