Failure Investigation of HSS Counter Punch Tool

The manufacturing processes such as shaping, forming, cutting, heat treatment and joining processes are being adopted in engineering applications, and various types of tools are necessarily being deployed during these operations to produce components. In this context, the failure of HSS counter punch tool used in cold forging is reported from an industry, as cold forging is a part of forming processes. The problem has been entrusted to investigate the cause of failure taking into account the selection of input parameters considered during cold forging and also the steps involved in the tool making. The material M35 HSS tool had developed a long crack along the periphery passing through the central axis of the counter punch tool. The mechanical and metallurgical investigations were done involving hardness, microstructure, retained austenite measurement, fractography as well as the non-destructive tests, viz., visual inspection, dye penetrant test and ultrasonic detection as a part of this study. The investigation revealed fatigue-induced damage due to the application of one-time load during forging caused by the microstructural changes observed during the post processes. The root cause of failure of the tool is established based on the analysis and interpretation of the experimental data. Further, the reason of failure is communicated to the industry along with the possible solutions from the point of avoiding failure occurrence in future.