Role of preheating and specific energy input on the evolution of microstructure and wear properties of laser clad Fe-Cr-C-W alloys

Synthesis of Fe-Cr-C-W alloy (10 : 4 : 1 : 1, wt(%)) was carried out on AISI 1016 steel substrate using laser cladding technique which lead to the development of a suitable alternate for cobalt bearing wear resistant alloys. This study involved understanding of process variables like preheating temperature and specific energy input on the evolution of microstructures and their effect on wear resistance properties. The microstructure was examined with a scanning electron microscope and various types of complex carbides were identified using both energy dispersive x-ray and auger spectroscopy facilities. A combination of MC, M7C3 and M6C types of carbides of certain proportions (formed at a preheating temperature of 484 degrees C with specific energy input of 9.447 KJ/cm(2)) has been found to be most attractive for achieving an optimum combination of microhardness and steady state friction coefficient values. A similar advantage may be derived at a lower level of specific energy input of 8.995 KJ/cm(2) but with a higher preheating temperature of 694 degrees C. However, increasing the specific energy input to 12.376 KJ/cm(2) can significantly soften the matrix. (C) 2000 Kluwer Academic Publishers.