Study on the Friction and Wear Behavior of a High-Speed Steel Tap in Tapping of Nickel-Based High-Te Article Abstract
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Published: February 28, 2005
A series of standard taps and modified-tooth taps with a cutting cone angle of 7°30~′ were prepared from high-speed steel W9 and used to tap nickel-based high-temperature alloy GH4169. The surface profiles of the tap tool flanks were observed using a scanning electron microscope, and the hardness of the workpiece bottom hole was measured using a microhardness meter. It was found that the friction torque was about 45% of the total torque as tapping with the standard taps. In this case many deep grooves appeared along the cutting speed direction and a large amount of adhered substance existed on the back face of the tooth tap, which were attributed to the abrasive action of the hard particles of GH4169 and the severe work-hardening. Different form the cases for the standard taps, the friction torque for the modified-tooth tap was reduced by 65% and the wear of the tap was significantly decreased as well, which was attributed to the unique epigenesis forming mode of the modified-tooth tap. Namely, the epigenesis forming mode of the modified-tooth tap contributed to greatly decrease the contact area between the tap teeth and the flank of the screw thread to be tapped and the possibility for the tap tooth to be clutched by the screw thread to be tapped owing to severe elastic deformation.