In industry, hardened steels are used in manufacturing of the products such as machine parts and components. In this context, surface quality and vibration play a significant role for control of cutting parameters and cutting conditions in turning process of hardened steel materials. In this study, it was aimed to investigate the effect of machinability on surface quality (Ra and Rz) and vibration in hard turning of conventional heat treated (CHT) and tempered (T) AISI 4140 (42CrMo4) steel samples using ceramic cutting tools under dry environment. They were selected as cutting parameters; four different cutting speeds (120, 160, 200, and 240 m/min), three different feed rates (0.05, 0.10, and 0.15 mm/rev), and depth of cut (0.2 mm). To make the turning process more efficient and to measure the occurring vibrations, the data were obtained online from the ceramic cutting tool by accelerometers in three axes (x-Ch1, y-Ch2, and z-Ch3 directions). In addition, test results of hardness, tensile, microstructure images, Ra - Rz values, and chip thickness values of the experiment samples were analyzed and compared. With the microstructure obtained after the tempering process applied to the T sample, it was seen that it is more machinable and affects the surface quality - vibration positively. The results showed that the most important cutting parameter affecting vibration and surface quality was found to be the feed rate. The lowest Ra value was found as 0.144 μm at 200 m/min of cutting speed and 0.05 mm/rev of feed rate in the T sample. The lowest vibration amplitude value (Ch3) was measured as 0.0023 gRMS (Root Mean Square) at 120 m/min of cutting speed and 0.05 mm/rev of feed rate. According to the Ra and Rz values found in the literature studies, better surface qualities were obtained in the present study.

在工业中，硬化钢用于制造机械零件等产品。在这种情况下，表面质量和振动对于控制淬硬钢材车削过程中的切削参数和切削条件起着重要作用。在这项研究中，本研究旨在研究可切削性对传统热处理（CHT）和回火（T）AISI 4140（42CrMo4）钢样品硬质车削时表面质量（Ra和Rz）和振动的影响，使用陶瓷切割工具在干燥的环境。选择它们作为切削参数；四种不同的切割速度（120、160、200和240 m / min），三种不同的进给速度（0.05、0.10和0.15毫米/转）和切割深度（0.2毫米）。为了提高车削过程的效率并测量发生的振动，这些数据是通过三个方向（x-Ch1，y-Ch2和z-Ch3方向）上的加速度计从陶瓷切削刀具在线获得的。另外，分析并比较了测试样品的硬度，拉伸，显微组织图像，Ra-Rz值和切屑厚度值的测试结果。将回火过程后获得的显微组织应用于T样品，可以看出它具有更高的机械加工性，并会积极影响表面质量-振动。结果表明，影响振动和表面质量的最重要切削参数是进给速度。在T样品中，在200 m / min的切削速度和0.05 mm / rev的进给速度下，最低Ra值为0.144μm。在120 m / min的切割速度和0的条件下测得的最低振动振幅值（Ch3）为0.0023 gRMS（均方根）。进给速度为05毫米/转。根据文献研究中发现的Ra和Rz值，在本研究中获得了更好的表面质量。