Investigation of cutting performance of high chromium white cast irons by wire erosion

It is known that high chromium white cast irons (YKBDD) have good wear resistance and toughness. Because of these features, they have a wide usage area. Due to the chromium carbide in its structure, its mechanical strength and wear resistance are superior to other cast iron and low-chrome white cast irons. It can be said that these features turn into a disadvantage for machinability with machining. Machinability is very difficult due to the presence of chromium carbide in the machining processes. In the thesis study, specially molded YKBDD samples were subjected to softening, casting (not heat treated) and hardened heat treatment processes, respectively. The obtained samples were cut by wire electrical discharge machining (WEDM). As a result of the processes, the hardness, microstructure, SEM and surface roughness of the samples were determined. As a result of machining with wire erosion, the change of workpiece machining speed (IIH), current (I) and surface roughness (Ra) according to the process parameters were performed for three different samples. As a result of the evaluation, the processing speed was determined as the highest raw sample among the raw, soft and hard samples. In the voltage-current ratio, the hard samples were calculated as the samples with the highest resistivity. According to the surface roughness results, it is recommended to evaluate the relationship between hardness and resistivity together. When the result of the ANOVA analysis was evaluated, it was determined that the most important processing parameters were the material (hard, soft and raw) and the impact time. It has been observed that the contribution of wire speed, water pressure and percussion dwell time is very small.