The aim of this work is to investigate the effect of titanium nitride coating for various treatment times (0.5-4 h) by cathodic cage plasma deposition (CCPD) on surface properties of AISI D6 tool ...steel. The obtained results depict micrometric-sized TiN film deposition under all processing condition with improved surface hardness and corrosion resistance. Raman and EDS analysis are used to calculate N/Ti ratios for stoichiometric calculations of samples. This study depicts that the surface properties of tool steel can be effectively improved by TiN film deposition using CCPD, with low processing time, low processing temperature and better uniformity, as compared to conventional techniques. Additionally, the problems associated with the conventional TiN films such as pores and voids are eliminated. This technique is compatible with industrial-scale applications, and thus results from this study are expected to be beneficial for the surface engineering industry.
Machining is a widely used manufacturing process that involves removing material from a workpiece. During this process, more than 95 % of the mechanical energy from the machine tool's electrical ...motor is converted into heat. This can cause the cutting tool's temperature to soar to extremely high levels, reaching up to 1200 °C or even higher, especially when working with hardened steels. To cool down the machining region, cutting fluids are commonly employed in industries. However, these fluids are not considered sustainable because they pose environmental pollution risks, are costly, challenging to dispose of properly, and can also be hazardous to operators' health. Moreover, in some applications, cutting fluids are not recommended. Considering these issues, this research aims to propose and test a more sustainable approach. The method involves using a closed-circuit system where a mixture of water and ethylene glycol circulates internally in polycrystalline cubic boron nitride (PCBN) tools. These tools are employed in the turning operation of AISI D6 hardened steel and are compared with conventional dry machining. The study utilizes a design of experiment (DOE) and analysis of variance (ANOVA) to plan and analyze the results with statistical reliability. Key output variables considered include cutting temperature, tool life, cutting forces, and surface roughness. The implementation of the internally cooled tool (ICT) system has shown significant benefits. It notably reduces the temperature of the tool's rake face, as measured using a thermographic camera. Despite not being the main variable affecting the maximum temperature, the cooling system plays a crucial role in achieving these improvements. The ICT system also substantially increases the tool life in comparison to conventional dry machining across all tested cutting conditions. While the feed rate remains the most influential factor affecting cutting forces due to increased cutting area, the cooling system also plays a significant role. The ICT system, with reduced temperatures, performs better in this regard. As for surface roughness, the condition of the tool edge emerges as the sole significant factor. Surprisingly, the worn tool provides better surface finishing due to the presence of crater wear. With conventional dry machining, higher cutting temperatures lead to increased tool wear, primarily caused by abrasion and attrition.
•Internally cooled tool (ICT) was used in turning AISI D6 hardened steel with PCBN tools;•An internal cooling system for the sustainable tool has been developed, eliminating the use of cutting fluids;•The tool temperature was reduced, and the machining force increased when using ICT as compared to conventional dry machining;•ICT increased the tool life in all cutting conditions tested;•The ICT system reduced crater wear via lower temperature, with abrasion and attrition as dominant wear mechanisms.
Abstract AISI D6 tool steel and AISI 304 stainless steel are among the most widely used material in the industry. However, this application field can still be expanded through the coatings ...deposition. In this regard, the objective of this work was to evaluate the impact of coatings application by cathodic cage technique using Hastelloy’s cathodic cage, on corrosion resistance of these steels. Two treatment temperatures were compared. The samples were characterized by Optical Microscopy, Scanning Electron Microscopy, Energy Dispersive Spectroscopy, X-Ray Diffraction with the application of the Rietveld routine and corrosion test. The results showed the formation of multiphase layers that contributed to corrosion potentials reduction for treatments at 400 °C, being more effective when applied on AISI D6. It was observed that the corrosion resistance is influenced by the temperature, which was attributed to the precipitation of chromium nitride and iron oxide at 450 ºC.
Abstract AISI D6 tool steel and AISI 304 stainless steel are among the most widely used material in the industry. However, this application field can still be expanded through the coatings ...deposition. In this regard, the objective of this work was to evaluate the impact of coatings application by cathodic cage technique using Hastelloy’s cathodic cage, on corrosion resistance of these steels. Two treatment temperatures were compared. The samples were characterized by Optical Microscopy, Scanning Electron Microscopy, Energy Dispersive Spectroscopy, X-Ray Diffraction with the application of the Rietveld routine and corrosion test. The results showed the formation of multiphase layers that contributed to corrosion potentials reduction for treatments at 400 °C, being more effective when applied on AISI D6. It was observed that the corrosion resistance is influenced by the temperature, which was attributed to the precipitation of chromium nitride and iron oxide at 450 ºC.
Die and mould makers frequently employ AISI-D6 steel. First, 32 trials of electrical discharge machining (EDM) are carried out on the aforementioned material. A variety of EDM procedure performance ...measures, including tool wear ratio (TWR), material removal rate (MRR), and surface roughness (Ra), are taken into account, as well as the pulse time (Ton), pulse current (I), and pulse voltage (V). Operators are guided by process. Increasing MRR and Ra concentrations and decreasing TWR concentrations were found to increase pulse on-time values. As a result of increasing the pulse current, physical removal rate, tool wear ratio and surface unevenness increased. As a result of the increased voltage, the MRR, TWR, and Ra values were all reduced. The outcomes are predicted using ensemble machine learning models. The experimental data used to create estimation models for MRR, TWR, and Ra. In addition, an unknown set of experiments has validated the model-based predictions.
The main objective of this work is to evaluate the tool life and the workpiece surface roughness when applying a vegetable-based cutting fluid by minimum quantity of lubricant (MQL) at three ...different directions (main tool flank face, secondary tool flank face, and overhead) in turning AISI D6 hardened steel with polycrystalline cubic boron nitride (PCBN) tools with Al
2
O
3
ceramic binder and TiN coating. Dry cutting was also tested for comparisons. Tool wear analyses were performed on the tools at the end of their lives within a scanning electron microscope (SEM). The application of the cutting fluid by MQL technique in the direction between the main tool flank face and the workpiece showed better results than the dry condition. The application of MQL through other directions (overhead and between the secondary tool flank face and the workpiece) also showed competitive results. Abrasion and adhesion were the prevailing mechanisms for the wear of the tools.
Sustainability is a concept which is widely considered nowadays, including in factories where machining operations are present. The search for methods able to improve the performance of industrial ...processes without damaging the environment or the worker's health has been the main goal of several investigations. In this context, cryogenic machining is a technique that has been studied as an alternative to the use of mineral oil-based cutting fluids, mainly in the machining of titanium and nickel alloys. Investigations on the cryogenic machining of hard tool steels are still scarce in the literature. This article presents results from a series of turning trials under dry and cryogenic conditions using a hardened AISI D6 tool steel bar (57 HRC) as the workpiece. For the cryogenic machining tests, liquid nitrogen was delivered to the flank face, rake face and on both faces of PCBN inserts. The main cutting parameters (cutting speed, feed rate, and depth of cut) were kept constant during the trials. Tool wear and chip morphology were the output variables studied. The results show that the liquid nitrogen was able to reduce the cutting tool wear, providing a tool lifetime around 50% longer compared with the dry process. Moreover, the frequency of chip segmentation was diminished under cryogenic conditions in comparison with the dry process.
Today, the AISI D6 tool steel has been employed in the manufacture of dies and molds that require high mechanical properties. Such hard material is not trivial to machining. Milling free-form ...geometries of D6 is a challenge usually faced at die and mold industries. Therefore, the current paper presents an investigation of free-form milling of hard material AISI D6 tool steel using a ball-end cemented carbide cutting tool. The influence of the toolpath direction (descendant and ascendant) and tool-workpiece surface contact were examined, and the machining forces, surface roughness, tool wear, and tool life were evaluated. The experiments were performed in two kinds of workpieces: in the first one, the milled surface was a cylindrical and in the second, the surface was inclined planes (with three different inclinations). The results indicate that the most influential factor for tool life was tool vibration. The higher the vibration, the shorter the tool life. Further, unlike milling of ordinary materials for molds and dies, the engagement of the center of the tool tip during cutting is advantageous for the machining process of hard materials because it improves cutting stability, thus reducing surface roughness and increasing tool life.
•Models were developed for predicting MRR and TWR during EDM of AISI D6 tool steel.•Analysis of variance was used to validate the developed models.•Effect of EDM parameters on MRR and TWR was ...explored.•The optimum condition for EDM process of the AISI D6 tool steel was suggested.
In this investigation, response surface method was used to predict and optimize the material removal rate and tool wear ratio during electrical discharge machining of AISI D6 tool steel. Pulse on time, pulse current, and voltage were considered as input process parameters. Furthermore, the analysis of variance was employed for checking the developed model results. The results revealed that higher values of pulse on time resulted in higher values of material removal rate and lower amounts of tool wear ratio. In addition, increasing the pulse current caused to higher amounts of both material removal rate and tool wear ratio. Moreover, the higher the input voltage, the lower the both material removal rate and tool wear ratio. The optimal condition to obtain a maximum of material removal rate and a minimum of tool wear rate was 40μs, 14A and 150V, respectively for the pulse on time, pulse current and input voltage.
Wear model in turning of hardened steel with PCBN tool Camargo, José C.; Dominguez, Dany Sanchez; Ezugwu, Emmanuel O. ...
International journal of refractory metals & hard materials,
11/2014, Letnik:
47
Journal Article
Recenzirano
In this study a mathematical–computational model of tool wear of PCBN (polycrystalline cubic boron nitride) was developed in turning of quenched and tempered AISI D6 steel (57 HRC) using experimental ...planning and statistic techniques. On the experimental trials many parameters are important such as: surface roughness, cutting force and tool wear. These parameters were evaluated according to their statistical significance using Statistica® and Matlab® softwares. Through a multiple-regression analysis, it was possible to establish a mathematical model for estimating tool wear as a function of the cutting parameters. This model enhanced estimation of the ideal cutting conditions for turning hardened steel, i.e., those that generate minimum damage on the PCBN tool without compromising productivity.
•Turning of quenched and tempered AISI D6 steel (57 HRC) using experimental planning and statistic techniques was studied.•PCBN cutting tool was used under dry condition.•Through a multiple-regression analysis, it was possible to establish a mathematical model for estimating tool wear.•This model enhanced estimation of the ideal cutting conditions for turning hardened steel.•Tool wear mechanisms were analyzed within SEM.
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