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Tools for metal forming need to be re-conditioned or replaced when their profile accuracy is no longer satisfactory due to wear,or when certain surface damage emerges due to wear and fatigue.A way to improve the wear and fatigue resistance of such metal tools is to increase the surface hardness and toughness of the tool materials and to introduce compressive surface residual stresses.Previous studies have found that by using grinding heating as a thermal source,a hardened layer of significantly superior mechanical properties can be generated.However,the research to date has been limited to surface grinding which is on a straight,flat grinding path.This paper aims to explore the applicability of the grinding-hardening technique to a cylindrical workpiece.It was found that cylindrical grinding introduces significant differences in heat conduction and convection,caused by the overlapping of heating/cooling zones.In traverse grinding,the consecutive tempering by the overlapping of the heating/cooling cycle leads to a non-uniform hardened layer,and produces varied microstructures and uneven hardness across a ground surface.Wheel wear changes the heat source intensity significantly,which in turn brings about dissimilar hardened layer structures and residual stresses.Plunge grinding,on the other hand,can make a relatively uniform hardened layer and residual stress distribution.The result shows that a higher total feed in plunge grinding produces a thicker hardened layer and a greater compressive residual stress.An investigation into the effect of wheel conditions and operation parameters concluded that it is possible to produce a relatively uniform hardening layer on a cylindrical workpiece if an in-situ wheel dressing can be applied and optimized.