Influence of Soaking Periods in Cryogenic Treatment of Tungsten Carbide

Abstract

Improvement in wear resistance and hardness of cutting tool material is one of the most important challenges in machining operation. This issue can be overcome by improving the wear resistance and hardness by cryogenic treatment of tungsten carbide. In this work it is tried to study the effect of different soaking periods in cryogenic treatment of tungsten carbide. The experiments were conducted at temperature of 88K at different soaking periods of 8hrs, 16hrs, 24hrs and 30hrs on commercially used tungsten carbide. Further efforts were made to quantify and confirm the effect of different soaking period along with the mechanism responsible for change in the hardness and wear resistance by measuring Rockwell hardness and weight loss during wear test. In addition to this OM, SEM, EDX and XRD tests were also conducted to support the results.The obtained result shows that there is a significant decrease in weight loss of 8hr soaked sample out of different soaking periods but, there was no change in bulk hardness. In addition to this the formation of carbide and change in particles size was observed in SEM and XRD after cryogenic treatment. The weight loss during sliding wear test indicates the cryogenically treated tungsten carbide is more wear resistance due to increase in population density of carbides. Microstructure analysis of worn surface reflects the mechanism behind the improvement of mechanical properties.