Hybrid machining versus hard turning-investigation on process induced residual stresses (original) (raw)
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Key Engineering Materials, 2014
Residual stress is one of the most important surface integrity parameter that can significantly affect the service performance of a mechanical component, such as: contact fatigue, corrosion resistance and part distortion. For this reason the mechanical state of both the machined surface and subsurface needs to be investigated. Residual stress induced by dry and cryogenic machining of hardened AISI 52100 steel was determined by using the X-ray diffraction technique. The objective was to evaluate the influence of the tool cutting edge geometry, workpiece hardness, cutting speed, microstructural changes and cooling conditions on the distribution of the residual stresses in the machined surface layers. The results are analysed in function of the thermal and mechanical phenomena generated during machining and their consequences on the white layer formation.
Study and analysis of Cryogenic Machining of Hard Components and investigation of tool wear
international journal of engineering trends and technology, 2016
In Nuclear Engineering industries and aerospace industries, surface finish and less tool wear properties are very important, which requires “Difficult to machine” materials like hast alloy, wasp alloy, tool steels and carbides. Nuclear engineering industries, aerospace industries, food processing industries find wide applications of such materials. In such situations, we cannot compromise quality with cost and to achieve such a high quality surface finish, finishing or super finishing processes are required due to which it's cost goes up. The present work explores the effect of cryogenic coolant in the machining of hard materials like Inconel 625 from an industrial perspective with emphasis on higher productivity and greater tool life as well as reliable performance characteristics. This work is an attempt to analyze the tool wear by controlling the variable parameters such as speed, feed and depth of cut. The combined effects of these parameters on tool wear are to be establish...
International Journal of Machine Tools and Manufacture, 2015
The researchers have worked on many facets of machining of hardened steel using different tool materials and came up with their own recommendations. Researchers have tried to investigate the effects of cutting parameters, tool materials, different coatings and tool geometry on different machinability aspects like, the tool life, surface roughness, cutting forces, chip morphology, residual stresses and the tool-chip interface temperature under dry and/or semi-dry and/or flood cooling environment during machining of hardened steels while many of them have ventured to characterize the wear phenomenon. Good amount of research has been performed on an analytical and/or numerical and/or empirical modeling of the cutting forces, tool-chip interface temperature, and tool wear under orthogonal/oblique cutting conditions during machining of hardened steels. This paper presents a comprehensive literature review on machining of hardened steels using coated tools, studies related to hard turning, different cooling methods and attempts made so far to model machining performance(s) so as to give proper attention to the various researcher works.
CIRP Annals - Manufacturing Technology, 2012
This paper presents the results of an experimental investigation to determine the effects of cryogenic coolant on surface integrity in orthogonal machining of hardened AISI 52100 bearing steel. Experiments were performed under dry and cryogenic conditions using chamfered CBN tool inserts. Several experimental techniques were used in the analyzing of the machined surface and subsurface: optical and scanning electron microscopes (SEM) were utilized for the surface topography characterization; chemical characterization (phase study) was carried out by means of Energydispersive spectroscopy (EDS) techniques; and X-ray diffraction (XRD) technique was used to determine residual stresses and phase changes induced by dry and cryogenic machining. The results show the benefits and the future potential of cryogenic cooling for surface integrity enhancement to achieve improved product's functional performance in hard machining.
In now days machining without the use of any coolant is become more popular due to safety of the environment. Because of this demands for increasing tool life without use of coolants are more. So according to this problem some of new machining techniques are considered like dry machining and cryogenic machining. Metal cutting is important in metal manufacturing process to achieve required shape and size. Many of the metal cutting industries invented different ways of improve the life of single point cutting tool in to increase the rate of the production and to reduce the cost of product, which is the major need of today's the manufacturing Industry. The goal of this paper to improve the tool life by various coatings on tungsten based cemented carbide cutting tool with cryogenic machining process. The coatings like Titanium nitride, aluminum oxide, and Titanium nitride/ aluminum oxide respectively are in use. This paper is about, the machining performance of coated tungsten based...
Tribology International, 2018
A new cooling technique is proposed to improve effectiveness of the minimum quantity lubrication (MQL) and cryogenic carbon dioxide (CO2) cooling in high performance machining of hard-to-cut materials. The combination of minimum quantity carbon dioxide and oil (CMQL) supplied from the rake face are compared with CO2 and MQL supplied from rake and flank faces, respectively, as well as only CO2 supplied from rake face, in turning of Ti6Al4V and Inconel 718. Tool wear, surface roughness and temperature measurements were performed to quantify the cooling impact of the various methods. Based on the systematical test results, CMQL was identified as the most favorable cooling method considering environmental impact, tool wear, surface finish, chip formation and cutting forces.
Journal of Materials Research and Technology, 2019
This study examined the hard turning of AISI D2 cold work tool steel subjected to deep cryogenic processing and tempering and investigated the effects on surface roughness and tool wear. In addition, the effects of the deep cryogenic processes on mechanical properties (macro and micro hardness) and microstructure were investigated. Three groups of test samples were evaluated: conventional heat treatment (CHT), deep cryogenic treatment (DCT-36) and deep cryogenic treatment with tempering (DCTT-36). The samples in the first group were subjected to only CHT to 62 HRc hardness. The second group (DCT-36) underwent processing for 36 h at −145 • C after conventional heat treatment. The latter group (DCTT-36) had been subjected to both conventional heat treatment and deep cryogenic treatment followed by 2 h of tempering at 200 • C. In the experiments, Al 2 O 3 + TiC matrix-based untreated mixed alumina ceramic (AB30) and Al 2 O 3 + TiC matrix-based TiN-coated ceramic (AB2010) cutting tools were used. The artificial intelligence method known as artificial neural networks (ANNs) was used to estimate the surface roughness based on cutting speed, cutting tool, workpiece, depth of cut and feed rate. For the artificial neural network modeling, the standard back-propagation algorithm was found to be the optimum choice for training the model. Three different cutting speeds (50, 100 and 150 m/min), three different feed rates (0.08, 0.16 and 0.24 mm/rev) and three different cutting depths (0.25, 0.50 and 0.75 mm) were selected. Tool wear experiments were carried out at a cutting speed of 150 m/min, a feed rate of 0.08 mm/rev and a cutting depth of 0.6 mm. As a result of the experiments, the best results for both surface roughness and tool wear were obtained with the DCTT-36 sample. When cutting tools were compared, the best results for surface roughness and tool wear were obtained with the coated ceramic tool (AB2010). The macroscopic and micro hardness values were highest for the DCT-36. From the microstructural point of view, the DCTT-36 sample showed the best results with homogeneous and thinner secondary carbide formations.
Dry and Cryogenic Machining: Comparison from the Sustainability Perspective
Sustainable Manufacturing, 2012
Modern manufacturing processes continue to demand high quality products and processes at reduced costs and with greater environmental compliance. This has led to a critical consideration of the use of conventional cutting fluids used in most machining processes. Continued use of cutting fluids poses major problems as they they are hazardous for the operating personnel on the shop floor. They are also carcinogenic, harmful to the environment and cause high costs. The major focus of the proposed paper is the analysis of experimental work on machining under dry and cryogenic conditions in turning of Al 7075-T651 alloy to achieve environmental and economic benefits and improved surface integrity and fatigue life of the machined product, thus aiming at a more sustainable product. In particular, a preliminary evaluation of the fatigue life of the component is presented based on a microstructure-based model, which varies with the used manufacturing process. The overall results show that cryogenic cooling has the potential to improve the product and process through its superior performance in terms of the machined surface and sub-surface characteristics and the related environmental and economic performance.
REVIEW OF THE CRYOGENIC MACHINING IN TURNING AND MILLING PROCESS
Cryogenic Coolents are used in conventional machining in material removing process can increase tool life, better surface finish, dimensional accuracy, and reduce the cutting temp. Main objectives of this paper is to understand the cryogenic machining operations. Various research scholar has done the experimental investigation on the cryogenic coolants in different materials in turning and milling Process,. At the end of the review obsrved that cryogenic coolant is most favourable methods for material cutting operations in various aspects for future research is proposed.
The Effects of Cryogenic Treatment on Cutting Tools
IOP Conference Series: Materials Science and Engineering, 2017
Enhancing the cutting tool life is important and economic factor to reduce the tooling as well as manufacturing cost. The tool life is improved considerably by 92 % after cryogenic treatment. The cryogenic treatment is a one-time permanent, sub-zero heat treatment that entirely changes cross-section of cutting tool. The cryogenic treatment is carried out with deep freezing of cutting tool materials to enhance physical and mechanical properties. The cryogenic treatment improves mechanical such as hardness, toughness and tribological properties such as wear resistance, coefficient of friction, surface finish, dimensional stability and stress relief. The deep cryogenic treatment is the most beneficial treatment applied on cutting tools. The cryogenic treatment is the most advanced heat treatment and popular to improve performance of the cutting tool. The optimization of cryogenic treatment variables is necessary to improve tool life. This study reviews the effects of cryogenic treatment on microstructure, tribological properties of tool steels and machining applications of cutting tool by investigating the surface and performing the surface characterization test like SEM. The economy of cutting tool can be achieved by deep cryogenic treatment.