Failure Analysis of a M7X1 High-Speed Steel Tap.

This case study describes the failure of a M7x1 high-speed steel tap that experienced a torsional brittle fracture, while a crescent wrench was applied by hand to create threads in a steel brake caliper of a motorcycle. During this process, the tap was fractured into two pieces forming a 45° angle with respect to the long axis of the tap. The crack origin was in one of the flutes of the tap. The hardness of the original tap was well below the recommended per ASTM A600. The root cause of the failure and crack origin was determined through scanning electron microscopy (SEM), and a finite element analysis (FEA) was used to analyze the performance of the part under normal loading conditions. [ABSTRACT FROM AUTHOR]