Investigation into the effect of carbide content on wear resistance of austenitic stainless steel powder coated low and medium carbon steels by TIG method

In this study, low and medium carbon steel surfaces were alloyed with different powders by using tungsten inert gas (TIG) process. The microstructures and wear properties of the alloyed zones were investigated. In the experimental study, low and medium carbon steel surfaces were coated with stainless steel powder alloyed with cobalt, molybdenum and titanium, respectively. Following the surface alloying, conventional characterization techniques, such as optical microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction were employed for studying the microstructure of the alloyed zone. Hardness measurements were performed across the alloyed zone and wear properties of the surfaces were evaluated by pin-on-disc abrasive wear and block-on-disc adhesive wear testing method.As a result of surface alloying applications using GTA process; adhesion between substrate materials and composite powders was obtained successfully at both low (50 A) and high (100 A) energy inputs. However, it was observed that the elements of cobalt and molybdenum did not melt completely at low energy input. It was observed that M23C6 carbides are formed in microstructure and these carbides are present along the grain boundaries in the Mo- reinforced coating, in the austenitic phase in the Ti- reinforced coating and both in the austenitic phase and along the grain boundaries in the Co- reinforced coating. By increasing energy input M23C6 carbides dissolve in microstructure in higher amounts and these carbides are more homogeneously distributed.It was observed that the highest hardness and wear resistance in both abrasive and adhesive condition among the specimens was obtained from austenitic stainless steel specimens coated with Ti and it was followed by specimens coated with Mo and Co, respectively.Keyword; Surface alloy, GTA, Adhesive wear, Abrasive wear, Austenitic stainless steels powder.