Investigation into microstructural and wear characteristics of Fe-based coating layers produced with gas tungsten arc method

In this study, different Cr based FeCrC, B4C and Ti powders were coated on the surface of AISI 304 austenitic stainless steel with Gas Tungsten Arc (GTA) method and the effects of carbide and other phases on the hardness and abrasive wear behaviours were investigated. The microstructures of coatings were examined by using optical microscopy, scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) respectively. Macrohardness and microhardness of the surface of coating layers were measured, the wear tests were performed in loads of 5, 10 and 20 N, by pin-on-disc test apparatus and the weight loss values were calculated. Besides, penetration proportions of coated layers were calculated.For GTA coatings, 66 % Cr based FeCrC powders and a welding current of 135 A was determined to be the most suitable. The different proportions of FeCrC powder were added in B4C and Ti powder, and formed the coating. It was observed for examining the microstructure that M2C, M3C, M7C3, M23C6, FeB, Fe2B, TiFe, TiFe2, Ti2Ni, TiNi3 and TiNi carbides were formed. This circumstance caused a decreasing the mass losses. Likewise, the macrohardness and microhardness of B4C coatings were very high, the results of abrasive wear tests, should the wear losses were the lowest for this coating.