SURFACE RESPONSE STUDIES OF COBALT BASED CLAD DEVELOPED THROUGH MICROWAVE ENERGY ON MARTENSITIC STAINLESS STEEL

Slurry erosion is always a major problem in the turbine of hydroelectric power plant. It mainly occurs due to the presence of sand particles in the water which flows through the hydraulic turbine leads to erosion of the blade surface. In order to overcome this problem some corrective measure need to be taken. It is very much essential to manufacture the turbine with steels which resist slurry erosion to a greater extent. Stainless steels (AISI-420) are serving as an excellent purpose in this concept and proved to be one of the most significant materials in this case. The surface characteristics of engineering components have a major effect on the life and serviceability of a component, thus it cannot be ignored in design. Surface engineering can assist to deal with these conditions to pick up the service life and also to improve the overall performance of the components. Therefore, the development of surface quality and its characterization plays a major role in surface engineering. However, cladding on the stainless steel material proves the most effective surface modification method in enhancing the slurry erosion resistance. The cobalt based clad exhibits excellent wear resistance. Accordingly, in the present work cobalt based clads were developed on martensitic stainless steel (AISI-420) respectively through microwave irradiation. A domestic microwave oven was used to develop cobalt based clad on the substrate (AISI-420). Wear behavior of developed clad surface was evaluated as per Taguchi orthogonal array. It is also observed from the regression model that the interactions between the variables had a very least effect on the erosive wear rate of the developed clad surface. As observed from the response of surface methodology, maximum erosion was observed at lower impact angle and higher rotational speed, where the minimum wear rate took place at higher impact angle with lesser speed.