Papers by Keyword: Hardened Steel

Abstract: To clarify the effect of using high-pressure coolant supply in combination with the intermittent cutting of hardened steel ASTM D2, intermittent cutting of hardened steel was performed with various sintered cubic boron nitride compact (cBN) tools. The result revealed that it was effective to use a high-pressure coolant supply method in combination for intermittent cutting of hardened steel. An effective tool material had a bonding phase of WC-Co-Al and a high content of cBN particles. Furthermore, the more suitable cutting edge shape was "a negative-land width of 0.13mm, a negative-land angle of 45°, and R honing of 0.04 mm".

Abstract: To study the face milling of hardened steel, the paper considers the chemical composition of the processed material, as well as metal-cutting, measuring equipment and tools. A full factorial experiment of face milling was carried out by the method of mathematical planning and matrices of levels of variation and planning of independent variables were compiled. The flatness of the samples was measured and the causes of plastic deformation were determined. To find an adequate mathematical model of flatness, a regression analysis was performed, and the correlation analysis revealed the closeness of the relationship between the variables under one-and two-factor influence on the response function. The hypersurfaces and lines of the function levels are projected, which made it possible to determine the optimal and effective cutting conditions graphically and analytically.

Abstract: Polycrystalline cubic boron nitride (cBN), a super-hard material used for hard turning, has good compatibility with steel. However, because chipping occurs from already existing defects and worn out cutting edges, a cBN insert must be exchanged within a short cycle time. By reducing chipping and flank wear, one can reduce the tool costs related to cutting processes and reduce the number of times the insert has to be exchanged, leading to improved productivity. In this study, the authors hypothesize that chipping and flank wear during cutting reduced by polishing a tool edge finely, uniformly, and smoothly before cutting. An apparatus capable of polishing and smoothing a cutting tool edge uniformly is developed. In the free-abrasive control method, application of an AC electric field during polishing is applied to suppress the scattering of abrasives from the tool cutting edge. Results show that scratches created by grinding are nonexistent. Moreover, a smooth cutting edge is obtained after polishing treatment. The wear width of the polished cBN tool under a cutting speed of 50 m/min is half of that of the non-polished treatment tool. Furthermore, no chipping occurs with the polished cBN tool under any conditions. Additionally, results show that the same effect is obtained even when Silicon carbide (SiC) abrasives are used. The n value calculated using the Taylor tool life equation is almost identical in cases of both diamond and SiC abrasives.

Abstract: Components miniaturization in industry leads to intensive research and development of efficient micro-technologies through research of different production processes, machines and tools. This paper presents experimental research on machinability of inclined surfaces on hardened steel workpieces with long-neck micro-end-ball mills. Workpiece is hardened AISI D2 tool steel (X155CrVMo-5). Micro-parts of this material is usually produced by non-conventional technologies such as electro-discharge machining (EDM) and laser beam machining (LBM), that allows machining of 2D or simple 3D structures. The effects of geometrical and cutting parameters on output machinability parameters in ball micro-milling were evaluated. Analysis of tool deflection, surface roughness and tool wedge wear was performed, in order to obtain the recommended cutting parameters for more precise, accurate and quality of micro-parts.

Abstract: Currently, many industries are seeking to lower the use of lubricating fluids in machining processes without losing the quality of the workpieces, as an affordable alternative arises the possibility to applicate the minimal quantity of fluid technique (MQF). This study is focused on interpretation and evaluation of hardened SAE 4340 steel milling process using the MQF at different flow rates compared to conventional lubrication. With the implementation of a data acquisition system to measure the milling dynamic, it was possible to know all the present variations on the power rating during the process. After the tests, an appropriate statistical analysis of results was applied in order to better understand the effects of the MQF and correlate the output variables. Moreover, this project allows us to have an applicable vision of cutting process costs and study an important industrial material. As a result, the measurement and validation of the use of MQF in tangential and frontal milling process of hardened steels show good correlation with the dimension of carbide cutters wears and influence on the level of power rating, as it is detailed in this paper.

Abstract: Drilling process has many applications including making molds and dies, all requires different quality of the drilled hole. The aim of this study is to establish models and optimization of cutting parameter to get the best hole quality, including enlargement diameter, circularity error and surface roughness in drilling hardened steel. Drilling experiments have been performed using different cutting parameters (i.e. cutting speed and feed rate) and employ and uncoated carbide drill under flooded cooling. The experimental results show that both of the cutting speed and feed rate significantly affect all responses. Models for responses have been developed for investigation in this study, and their optimizations have been obtained, showing better quality of the drilled hole produced at higher cutting speed and lower feed rate. Desirability for the optimum criteria is 0.944 at the highest cutting speed (60 m/min) and lowest feed rate (0.05 mm/rev).

Abstract: Abstract: Corner radius as a non-main cutting parameters, study of corner radius about cutting vibration is relatively small.Turning experiments use PCBN tool in CAK4085 CNC lathe,cutting hardened steel HRC50-52 Cr12MoV and hardened steel HRC62-64 GCr15, eddy current sensor measure the tool vibration amplitude of each group parameters, analysis influence of the corner radius for tool vibration amplitude. With corner radius increases, tool vibration amplitude increases. Research will contribute to the development of high-speed machining of hardened steel.

Abstract: Due to the transition region with different hardness, the milling process of assembled hardened steel die is prone to generate flutter, which is hard to ensure surface integrity of workpiece. By establishing the finite element model, the milling process of assembled hardened steel die was calculated by the finite element method. Effects of cutting parameters on milling force and milling temperature were achieved by the above finite element analysis. The laws of the stress and the thermal field distribution in the assembled transition region are analyzed and discovered. The analysis results demonstrate that milling force and milling temperature of the transition region changes in step leaping way. There is a close relationship between processing stability and cutting parameters. The stress and the thermal distribution of the transition region have a significant difference due to the changes in material hardness.

Abstract: Based on the cutting performance parameter of hardened steel 7CrSiMnMoV and the application of fuzzy synthetic evaluation principle, the essay establishes a two-level fuzzy synthetic evaluation model of the machinability of 7CrSiMnMoV. Choosing cutting force, cutting temperature and surface roughness of the workpiece produced during machining process as the evaluation index, data are measured through experiment and a synthetic evaluation of the machinability of hardened steel 7CrSiMnMoV is conducted. The result shows that it is reasonable to use cutting force, cutting temperature and surface roughness of the workpiece as evaluation index to evaluate the material machinability. And it also provides guidance to the selection of tools and the technological parameters during the process of cutting 7CrSiMnMoV.

Abstract: The cutting vibration has a great influence on the processing quality of Hardened steel. The research conducted in this paper is about how the cutting parameters influence the cutting vibration amplitude when the hardened steel is cut. The experiments were performed on CNC lathe CAK4085 with PCBN tool, where the cutting speed, feed rate, cutting depth and corner radius had been orthogonally combined. The cutting materials were hardened steel Cr12MoV and GCr15 whose hardness is HRC50-52 and HRC62-64. The cutting vibration amplitude under different group parameters was collected by electric eddy current sensors. An analysis about the influence rule of cutting parameters on cutting vibration amplitude had been made. With the increase of cutting speed, vibration amplitude will increase first, and then decrease. With the appropriate increase of feed rate, vibration amplitude will be reduced. With the increase of cutting depth and corner radius, vibration amplitude will both increase. This research can provide reference for improving cutting quality.