## 3 Results and Discussion  
Figure 2 shows cutting tool flank wear values at different workpiece preheating temperature and feed values. It can be seen that by preheating the workpiece at 200 \({}^{\circ}\)C, tool flank wear is reduced compared to conventional turning (at ambient temperature) at all cutting speeds. Although, increasing preheating temperature to 300 \({}^{\circ}\)C decreases tool flank wear continuously, by rising the primary temperature of workpiece to 400 \({}^{\circ}\)C, the flank wear values not only do not decrease but also increase compared to turning at 300 \({}^{\circ}\)C at cutting speeds of 96 m/min and 123 m/min. As it is indicated in Figure 2, these phenomena have been observed for both cutting tool feeds of 0.102 mm/rev and 0.175 mm/rev. Figure 3 presents scanning electron microscope (SEM) images that illustrate the differences in cutting tool flank wear and crater wear under various workpiece preheating temperatures and turning conditions. The comparison is striking, as it demonstrates a significant reduction in the severity of wear on the cutting tool's rake face when employing the preheating turning technique at 400 \({}^{\circ}\)C in contrast to traditional turning operation at room temperature. Figure 3a reveals that the tool flank wear width measures 119 \(\upmu\)m in conventional turning. However, in the case of hot turning at 200 \({}^{\circ}\)C and 300 \({}^{\circ}\)C, the tool flank wear width is reduced to approximately 108 \(\upmu\)m and 100 \(\upmu\)m, respectively (as shown in Figure 3b,c). Additionally, at a preheated temperature of 400 \({}^{\circ}\)C, the cutting tool flank wear width measures 107 \(\upmu\)m. This transition from a workpiece preheating temperature of 200 \({}^{\circ}\)C to 400 \({}^{\circ}\)C results in an increased number of fine particles from the workpiece material adhering to the tool flank face (as indicated in Figure 3). Consequently, in this scenario, the optimal workpiece preheating temperature to minimize tool flank wear is considered to be 300 \({}^{\circ}\)C.  
Figure 2: Effects of workpiece initial temperature and cutting speed on tool flank wear for f = 0.102 mm/rev and f = 0.175 mm/rev. Figure 3: _Cont._  
Figure 4a shows a magnified illustration of the white box distinguished in Figure 3a. In this figure, different areas on the worn tool have been identified using Energy Dispersive X-ray (EDS) maps. Therefore, to completely and precisely investigate the wear mechanism, different areas on the rake face and flank face of all cutting tools used, in this study, under different turning conditions have been identified by applying EDS maps. Figure 4 indicates that the tool wear mechanism in conventional turning is abrasive and adhesive types. On the rake face of the cutting tool, the area in which the workpiece material (chip) adheres on the tool surface has been marked with the phrase \"Fe\". This area is completely covered by iron (Fe-rich) and is therefore easily recognizable in EDS maps (Figure 4b). Table 1 shows the chemical composition of this figure which is the result of the analysis of point EDS spot 1. This chemical composition is exactly similar to that of workpiece material, so it can be concluded that this material is adhered/welded on the tool surface as Built-up Layer (BUL) [18]. To put it differently, there are instances where adhesion has been combined with abrasion, resulting in the specimen's material strongly adhering or welding to the tool's top coating (AlCr\({}_{2}\)O\({}_{3}\)). As the cutting process continues, this material is gradually removed from the tool's surface. Consequently, this process reveals the cutting tool's base coating layer (TiAlN), leading to areas where the top layer (Al,Cr)\({}_{2}\)O\({}_{3}\) has been removed, and chromium is no longer present. In these chromium-free areas, the first layer of coating has been stripped away (as shown in Figure 4c), and you can observe the (Ti,Al)N coating on the tool. For instance, the region marked within the oval in both Figure 4a,c is devoid of chromium.