A Study of the Effect of Cryogenic Treatment on the Performance of High Speed Steel Tools and Carbide Inserts

Cryogenic treatment has been acknowledged by some as means of extending tool life of many cutting tool materials, thus improving productivity significantly. However real mechanisms which guarantee better tool performance are still dubious. This implies the need of further investigations in order to control the technique more significantly. Studies on cryogenically treated HSS tools show microstructural changes in material that can influence tool lives. However little research has been done on other cutting tool materials. Cryogenic treatment of carbides has yet to be extensively studied. This work aims to study the effect of cryogenic treatment on M2 and S400 as well as Carbide inserts of SNMS120408 and SNMG120412MP grades. The tools were cryo-treated for 24 hours. The flank wear tests, sliding wear tests and hardness tests were conducted. In the process of ascertaining these findings, it was shown in this study that in flank wear tests cryogenically treated tool showed an increase in tool life. However in sliding wear test, weight loss in case of cryogenically treated tools was found to be more indicating the fact that the tool becomes more brittle after cryogenic treatment due to transformation of retained austenite to martensite as well as due to carbide refinement. Microstructural analysis and SEM analysis were done to support the results obtained. Performance of cryogenically treated tools largely depends upon the cutting conditions. Hence design of experiment (DOE) was employed to study the effect of cutting parameters on tool wear and tool life equations were developed illustrating the significant factors that affect performance of cryogenically treated tools.