Experimental investigation of the effects of hot turning parameters on the cutting tool wear and surface roughness of AISI630 hardened stainless steel

AISI630 is a stainless steel that is strengthened by precipitation-hardening mechanism. This steel has high hardness and low thermal conductivity, has made it one of the difficult-to-cut materials. These two factors have its machining is associated with high tool wear and poor workpiece surface quality. In this study, the conventional and hot turning of AISI630 hardened stainless steel have been investigated. To determine the effect of machining parameters on tool wear, a hot turning process up to a preheating temperature of 400°C was performed. Turning was conducted at three feed rates and three levels of cutting speed using PVD-(Ti,Al)N/(Al,Cr)2O3 coated carbide tools. Tool flank wear and wear mechanisms have been studied in different cutting conditions as well as different preheating temperatures using SEM microscope. Experimental results showed that the lowest wear on the free surface of the tool was obtained by hot turning at 300 °C. Hot turning at this temperature reduced the flank wear by 33%. Observation of the worn surface of the tools showed that the tool wear mechanism in hot turning and conventional turning is of the type of abrasive wear and adhesive wear.Moreover, at each cutting speed and feed, with increasing the workpiece initial temperature up to 400°C, the surface roughness decreases. The optimal values of temperature, cutting speed and feed rate were obtained using Minitab software with the aim of reducing tool wear and surface roughness.