Chip Formation and Coefficient of Friction in Turning S45C Medium Carbon Steel (original) (raw)
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Chip formation in turning S45C medium carbon steel in cryogenic conditions
2017
This paper presents the tribology issue regarding the chip formation in machining medium carbon steel (S45C) using a coated and uncoated carbide tools. The machining parameters under investigation were cutting speed, feed rate, and depth of cut under dry and cryogenic cutting condition using coated and uncoated carbide tools. The chip shape was largely depended on the combination of machining parameters, especially at high depth of cut and feed rate; the favorable chip was produced. Larger value of shear angle results in smaller shear plane area that provides benefits of lower cutting force needed to shear off the chips and lower cutting temperature being generated during the machining process.
1. INTRODUCTION Chip morphology refers to the characteristics of the chips produced in a manufacturing process, which aids in analyzing the performance of the machine tool, process parameters and product quality. If one masters in chip reading, it is easy to control throughput, turning costs, tool life and surface finish, leading to better process economics and increased process security. These issues are particularly timely today, because many companies are operating multiple shifts to meet growing market demand and running unattended turning operations. By interpreting chip size, shape, color, and direction, one will know how effectively the tools and machines are performing. It is possible to have peace of mind regarding unattended operation, because chip disposal is controlled, smooth and reliable. Whether unattended or attended, chip formation can wreak havoc on machine uptime. If unattended turning operations are run, concerns about chip control, throughput, surface finish, edge security and tool wear can be minimized to an extant. It is recommended that when first cuts are run, one should not limit oneself to checking workpiece, but also read your chips. The chip characteristics will tell immediately what machining data or tooling need fixing, so that we can adjust them. In addition, if anyone can become a chip expert who reads the chips properly, will be among a minority that understands that there is more to a chip than just a piece of metal. Chip formation processes in metal cutting, particularly in turning and drilling, have been studied extensively [1-10]. Elbestawi et al. [11], Ng et al., [12], and Becze et al. [13] have investigated chip formation and tool wear in high speed end milling of hardened steels. Ning et al. [14] have classified the chips observed from ball end milling of H13 hardened steel into four types: complete, unstable, critical, and severe chips. Kobayahsi [15] have discussed the mechanics and chip ABSTRACT The growing demand for high productivity machining and grinding particularly high strength and heat resistance materials need use of high cutting velocity and feed. Such machining and grinding inherently generate very large amount of heat and high cutting temperature, which not only reduces tool life but also impairs the product quality. Chip morphology (chip shape, colors and chip reduction coefficient) is a considerable instrument to predict optimum cutting parameters. It is very helpful in determining favorable machining environments. High production machining at high cutting velocity and feed rate generates large heat and high cutting temperature, which shortens the tool life and deteriorates the job quality. This problem becomes more severe during difficult to machine materials and under dynamic loading conditions. The conventional cutting fluids are not that effective in such high production machining particularly in continuous cutting of materials like steels. Machining of soft, sticky and ductile materials yields long continuous chips and rapid tool wear due to inefficient action of the cutting fluids. High-pressure coolant machining is starting to establish itself as a method for substantial increase of economical production in the metal cutting industry. Cutting with an excess amount of cutting fluids is still very common, even if a trend towards dry cutting is starting to grow fast. Research made in the past has shown the high potential with high-pressure coolant assisted machining compared to conventional cooling. The present work deals with experimental investigation in the role of high-pressure coolant jet on chip formation like chip shape, color and chip reduction coefficient in plain turning of medium carbon steel rod at different cutting velocities and feed rates by two types of carbide inserts (SNMM and SNMG) of different geometry. Chip morphology is used to differentiate, compare and choose the best among these three environments-dry, wet and high-pressure coolant systems. Compared to the other machining (dry and wet), high pressure coolant machining performed much superior mainly due to substantial reduction in cutting zone temperature enabling favorable chip formation and chip-tool interaction.
Tribological behaviour of coated carbide tools during turning of steels with improved machinability
Export Date: 27 October 2013, Source: Scopus, CODEN: STJVA, doi: 10.5545/sv-jme.2012.561, Language of Original Document: English, Correspondence Address: Sebhi, A.; Optics and Precision Mechanics Institute, University of Ferhat Abbes, Setif 19000, Algeria; email: sebhiamar@yahoo.fr, References: Jasppers, S.P.F.C., Dautzenbergb, J.H., Material behaviour in conditions similar to metal cutting: Flowstress in the primary shear zone (2002) Process and Technology, 122 (2-3), pp. 322-330. , DOI:10.1016/S0924-0136(01)01228-6;
Materials, 2022
The paper deals with the issue of cutting zone and chip compression. The aim was to analyse the microstructure transverse section of the cutting zone on a metallographic cut, due to determined values of chip compression and plastic deformation, which affect the cutting process efficiency. The tested cutting tool material was coated with cemented carbide. The selected workpiece materials were C45 medium carbon steel of ISO grade and 62SiMnCr4 tool steel of ISO (W.Nr. 1.2101) grade. In the experiments, a DMG CTX alpha 500 turning centre was used. The cutting speed and feed were varied, and the depth of the cut was kept constant during the turning. The plastic deformation and chip compression determine the efficiency of the cutting process. The higher compression requires more work to perform the process and, therefore, it requires more energy for doing so. With the increase of the cutting speed, the deformation for C45 steel is decreased. The rapid deformation reduction was observed w...
Journal of Manufacturing Processes, 2020
One of the important phenomena of orthogonal cutting process is the occurrence of the minimum uncut chip thickness, as its highly affects the process of cutting initiation and surface roughness. But nowadays non orthogonal i.e., oblique cutting process using special tools with continued cutting edge and high value of cutting angle λ s make new possibilities in the field of research. Hence, this paper presents the results of such analyzes and investigations of oblique cutting impact using tool with λ s € < angle < 0°, 60°> on the minimum uncut chip thickness during free-radial turning of C45 steel using sintered carbide edges S3OS with r n = 18, 28, 90 μm, respectively. The results show that the experimentally determined minimum uncut chip thickness decreases with the increase of the value of the λ s angle and in accordance with the derived theoretical Equations concerning the direction of the chip flow. Moreover, it establishes the possibility of significantly lowering the h min value with the increase of the absolute value of the angle λ s and it opens a new directions of tool edges for oblique cutting to finish machining and sheds new light on abrasive wear issues, during which micro-cutting may occur.
In turning many key factors like, type of tool bit and its setting angle, machining conditions, type of material to be machined, spindle speed, cutting speed and feed rate etc., plays an important role. Out of all tool bit and cutting speed plays vital role. In this study, on lathe Machine Turning operation has been carried out for different Steel materials such as Mild Steel, EN-8, EN-31 and OHNS by maintaining constant depth of cut and feed by using DNMG 110404 carbide insert tool bit and then with High speed steel (HSS) tool bit at various cutting speeds 400, 800, 1200, 1600 rpm respectively. The surface roughness values have been compared for both the tool bits and the cutting force values have been analyzed for carbide insert tool bit. From the study the effectiveness of carbide insert tool bit has been noticed for steel materials at various cutting speeds in turning operation.
International Journal of Engineering Research and Technology (IJERT), 2015
https://www.ijert.org/modeling-and-analysis-of-effect-of-cutting-parameters-on-product-quality-in-dry-turning-operation-of-mild-steel-using-carbide-high-speed-steel-tool https://www.ijert.org/research/modeling-and-analysis-of-effect-of-cutting-parameters-on-product-quality-in-dry-turning-operation-of-mild-steel-using-carbide-high-speed-steel-tool-IJERTV4IS080368.pdf Material removal plays an important role in finishing part/components. Information about cutting forces during machining can be considered as an index to evaluate the machinability of a material while considering the amount of heat in the cutting area, tool wear, quality of machined surface and accuracy of the part. In the present study, an attempt has been made to investigate the effect of cutting parameters (cutting speed, feed rate and depth of cut) on cutting forces (feed force, thrust force) and surface roughness for turning of mild steel using high speed steel (HSS) and carbide tool. Experiments were conducted on a precision lathe (HMT) and the influence of cutting parameters was studied using analysis of variance (ANOVA) based on adjusted approach. The results showed that with increasing the depth of cut and feed for a given RPM, cutting force increases. With the same cutting speed and depth of cut, the force variation is significant in both high speed steel (HSS) and carbide tool. The minimum cutting force requirement for machining the component (theoretically) is almost same with that of experimental value obtained by dynamometer.
Performance Evaluation of Carbide Tool on Turning of Alloy Steel
2017
The main objective of today's manufacturing industries is to produce low cost, high quality products in short time. The selection of optimal cutting parameters is a very important issue for every machining process in order to enhance the quality of machining products and reduce the machining costs. This paper investigates the machining of alloy steel to find optimal parameters for CNC turning process. The Taguchi method is used to formulate the experimental layout, to analysis the effect of each parameter on the machining characteristics and to predict the optimal choice for each turning parameters such as Speed, Feed and Depth of cut. It is found that these parameters have a significant influence on machining characteristics such as Material removal rate (MRR) and Surface roughness (SR). The Analysis of Variance (ANOVA) is used to study the performance characteristics in turning operation.
Effect of Rake Angle and Feed Rate on Chip Segmentation in Machining Carbon Steel 1050
IOP Conference Series: Materials Science and Engineering, 2019
A chip breaker plays an essential role for chip breaking as well as to enhance productivity and quality during the turning process. However, chip break as a tool is not able to break the chip and formulate continuous chip, that in turn, causes the tool to wear and the generate excessive heat. These affect the quality of the machined surface. Chip formation is influenced by cutting conditions and tool geometries such as spindle speed, feed rate, depth of cut and rake angle. In this study, experiments were carried out on carbon steel 1050 with chip breaker at a constant cutting speed of 275 m/mm with a depth of cut 0.9 mm. The effect of different feed rate and rake angle towards chip length formation were also investigated in the present investigation. The results obtained from the study indicates that segmented chips could be obtained at a feed rate of 0.4 mm/rev and a rake angle of -9°. Therefore, it could be concluded that the feed rate and rake angle can play a significant role in...
Surface and Coatings Technology, 2006
Four complementary methods are used to qualify the performance of the tribological system ''workmaterial-coated carbide cutting toolchip'', with the purpose of reaching a better global understanding of the capability of coatings: chip formation mechanisms, cutting forces, interface temperature are deduced from experiments and correlated with previous heat flux measurements already published. The experiments have been applied on the characterization of the frictional behaviour of a reference coating such as TiN, and of more advanced coatings such as TiAlN and TiAlN + MoS 2 , deposited on a WC-Co carbide substrate during the machining of steels. Results show that the TiN and (Ti,Al)N + MoS 2 coatings exhibit to the best tribological improvements compared to uncoated tools: important decrease of the tool -chip contact area, decrease of the thickness of the secondary shear zone and of the temperature at this interface, which lead to a decrease of the heat flux transmitted to the cutting tool substrate. The (Ti,Al)N coating exhibits an intermediate behaviour. Indeed, even if it improves somewhat some parameters such as the tool -chip contact length and the thickness of the secondary shear zone, the (Ti,Al)N coating does not enable a reduction of the interface temperature and has a limited influence on the heat flux transmitted to the substrate. D