scholarly journals Effects of Tool Wear on Machined Surface Integrity During Milling of Inconel 718

2021 ◽  
Author(s):  
Liang Tan ◽  
Changfeng Yao ◽  
Dinghua Zhang ◽  
Minchao Cui ◽  
Xuehong Shen
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Tool Wear ◽  
Surface Integrity ◽  
Inconel 718 ◽  
Flank Wear ◽  
Cutting Temperature ◽  
Machined Surface ◽  
Tool Flank Wear ◽  
Machined Surface Integrity

Abstract This paper investigates the effects of tool wear on the machined surface integrity characteristics, including the surface roughness, surface topography, residual stress, microhardness and microstructure, during ball-end milling of Inconel 718. Tool wear, tool lifetime, and cutting force are measured. In addition, a two-dimensional finite element-based model is developed to investigate the cutting temperature distribution in the chip–tool–workpiece contact area. Results show that the ball nose end mill achieves tool lifetime of approximately 350 min. The cutting forces increase sharply with a greater tool flank wear width, while the highest cutting temperature has a decreasing tend at a flank wear width of 0.3 mm. Higher tool flank wear width produces larger surface roughness and deteriorative surface topography. A high-amplitude (approximately −700 MPa) and deep layer (approximately 120 mm) of compressive residual stress are induced by a worn tool with 0.3 mm flank wear width. The surface microhardness induced by new tool is larger than that induced by worn tool. Plastic deformation and strain streamlines are observed within 10 mm depth beneath the surface. The results in this paper provide an optimal tool wear criterion which integrates the surface integrity requirements and the tool lifetime for ball-end finish milling of Inconel 718.

scholarly journals Effects of Machined Surface Integrity on High-Temperature Low-Cycle Fatigue Life and Process Parameters Optimization of Turning Superalloy Inconel 718

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2428
Author(s):  
Xiaoping Ren ◽  
Zhanqiang Liu ◽  
Xiaoliang Liang ◽  
Pengcheng Cui
Keyword(s):  
Residual Stress ◽  
High Temperature ◽  
Fatigue Life ◽  
Process Parameters ◽  
Surface Integrity ◽  
Inconel 718 ◽  
Low Cycle Fatigue ◽  
Cycle Fatigue ◽  
Machined Surface ◽  
Machined Surface Integrity

Machined surface integrity characteristics, including surface stresses, physical-mechanical properties and metallographic structures, play important roles in the fatigue performance of machined components. This work aimed at investigating the effects of machined surface integrity on high-temperature low-cycle fatigue life. The process parameters were optimized to obtain required surface integrity and fatigue life of the turning superalloy Inconel 718. The relationships between low-cycle fatigue life and machined surface integrity characterization parameters were established based on the low-cycle fatigue tests at a high temperature (650 °C). The sensitivities of turning process parameters to high-temperature low-cycle fatigue life were analyzed, and the optimization parameters were proposed with the goal of antifatigue manufacturing. Experimental results indicated that the impact order of the characterization parameters of machined surface integrity on the high-temperature low-cycle fatigue life were the degree of work hardening RHV, the residual stress in the cutting speed direction S22, the fatigue stress concentration factor Kf, the degree of grain refinement RD and the residual stress in the feed direction S33. In the range of turning parameters of the experiments in this research, the cutting speeds could be 80~110 m/min, and the feed rate could be 0.10~0.12 mm/rev to achieve a longer high-temperature low-cycle fatigue life. The results can be used for guiding the fatigue-resistant manufacturing research of aeroengine superalloy turbine disks.

Influence of Tool Flank Wear on Surface Integrity in Orthogonal Milling of Powder Metallurgy Superalloy

2012 ◽  
Vol 723 ◽  
pp. 182-187
Author(s):  
Jin Du ◽  
Zhan Qiang Liu
Keyword(s):  
Surface Roughness ◽  
Surface Integrity ◽  
Flank Wear ◽  
White Layer ◽  
Micro Hardness ◽  
Machined Surface ◽  
Tool Flank Wear ◽  
White Layer Thickness ◽  
Cemented Carbide Tools ◽  
Coated Cemented Carbide

Tool flank wear has the significant effects on machined surface integrity. The influences of tool flank wear on the cutting forces, surface roughness, microhardness and white layer thickness are investigated in this paper through orthogonal milling experiments. FGH95 powder metallurgy (PM) superalloys are machined with coated cemented carbide tools in the milling experiments. The experiment results show that with the increasing of tool flank wear, cutting force, surface roughness and white layer thickness increase. However, the machined surfaces micro-hardness aggravates with the increase of tool flank wear. It is found that, the machined surface roughness, micro-hardness and white layer increase dramatically especially when the tool flank wear exceeds 0.3mm. A conclusion is then be drawn that, the maximum acceptable tool flank wear land is 0.3mm from the view point of surface integrity when FGH95 PM superalloy is machined with coated cemented carbide tools.

Effect of Cutting Speed on Surface Integrity in High Speed Machining Nickel-Based Superalloy Inconel 718

2011 ◽  
Vol 697-698 ◽  
pp. 208-212
Author(s):  
Zhan Qiang Liu ◽  
Cheng Ming Cao ◽  
J. Du ◽  
Zhen Yu Shi
Keyword(s):  
Surface Roughness ◽  
Surface Integrity ◽  
Inconel 718 ◽  
High Speed ◽  
Cutting Speed ◽  
Cnc Machining ◽  
Machined Surface ◽  
Surface Residual Stresses ◽  
Machined Surface Integrity ◽  
Cutting Speeds

Surface integrity is becoming important to satisfy the increasing requirements service life of machined parts. The purpose of this study is to investigate the effects of cutting speeds on surface integrity of Inconel 718. Experiments are conducted on a CNC machining center under various cutting speeds. The machined surface integrity is evaluated in terms of surface roughness, microhardness and residual stress. Experimental results show that machined surface integrity of Inconel 718 is sensitivity to the variations of cutting speeds. The surface roughness firstly increases with the cutting speeds increasing at the range from 50 m/min to 200 m/min, then decreases with the further increasing of the cutting speeds. For microhardness, it can be seen that work-hardening for the machined surface is serious. The surface residual stresses are tensile ones at the range of the selected cutting speeds from 50 m/min to 3,000 m/min in this research.

scholarly journals Influence of turning tool wear on the surface integrity and anti-fatigue behavior of Ti1023

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110112
Author(s):  
Li Xun ◽  
Wang Ziming ◽  
Yang Shenliang ◽  
Guo Zhiyuan ◽  
Zhou Yongxin ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Plastic Deformation ◽  
Titanium Alloy ◽  
Fatigue Life ◽  
Tool Wear ◽  
Surface Integrity ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Machined Surface ◽  
Deformation Layer

Titanium alloy Ti1023 is a typical difficult-to-cut material. Tool wear is easy to occur in machining Ti1023, which has a significant negative effect on surface integrity. Turning is one of the common methods to machine Ti1023 parts and machined surface integrity has a direct influence on the fatigue life of parts. To control surface integrity and improve anti-fatigue behavior of Ti1023 parts, it has an important significance to study the influence of tool wear on the surface integrity and fatigue life of Ti1023 in turning. Therefore, the effect of tool wear on the surface roughness, microhardness, residual stress, and plastic deformation layer of Ti1023 workpieces by turning and low-cycle fatigue tests were studied. Meanwhile, the influence mechanism of surface integrity on anti-fatigue behavior also was analyzed. The experimental results show that the change of surface roughness caused by worn tools has the most influence on anti-fatigue behavior when the tool wear VB is from 0.05 to 0.25 mm. On the other hand, the plastic deformation layer on the machined surface could properly improve the anti-fatigue behavior of specimens that were proved in the experiments. However, the higher surface roughness and significant surface defects on surface machined utilizing the worn tool with VB = 0.30 mm, which leads the anti-fatigue behavior of specimens to decrease sharply. Therefore, to ensure the anti-fatigue behavior of parts, the value of turning tool wear VB must be rigorously controlled under 0.30 mm during finishing machining of titanium alloy Ti1023.

Experimental studies on graphite powder-mixed electro-discharge machining of Inconel 718 super alloys: Comparison with conventional electro-discharge machining

2018 ◽  
Vol 233 (2) ◽  
pp. 384-402 ◽  
Author(s):  
Santosh Kumar Sahu ◽  
Saurav Datta
Keyword(s):  
Thermal Conductivity ◽  
Residual Stress ◽  
Wear Rate ◽  
Tool Wear ◽  
Inconel 718 ◽  
Material Removal ◽  
Graphite Powder ◽  
Tool Wear Rate ◽  
Machined Surface ◽  
Electro Discharge Machining

Inconel 718 is a nickel-based super alloy widely applied in aerospace, automotive, and defense industries. Low thermal conductivity, extreme high temperature strength, strong work-hardening tendency make the alloy difficult-to-cut. In contrast to traditional machining, nonconventional route like electro-discharge machining is relatively more advantageous to machine this alloy. However, low thermal conductivity of Inconel 718 restricts electro-discharge machining from performing well. In order to improve the electro-discharge machining performance of Inconel 718, powder-mixed electro-discharge machining was reported in this paper. It was carried out by adding graphite powder to the dielectric media in consideration with varied peak discharge current. The morphology and topographical features of the machined surface including surface roughness, crack density, white layer thickness, metallurgical aspects (phase transformation, crystallite size, microstrain, and dislocation density), material migration, residual stress, microindentation hardness, etc. were studied and compared with that of the conventional electro-discharge machining. Additionally, effects of peak discharge current were discussed on influencing different performance measures of powder-mixed electro-discharge machining. Material removal efficiency and tool wear rate were also examined. Use of graphite powder-mixed electro-discharge machining was found to be better in performance for improved material removal rate, superior surface finish, reduced tool wear rate, and reduced intensity as well as severity of surface cracking. Lesser extent of carbon migration onto the machined surface as observed in powder-mixed electro-discharge machining in turn reduced the formation of hard carbide layers. As compared to the conventional electro-discharge machining, graphite powder-mixed electro-discharge machining exhibited relatively less microhardness and residual stress at the machined surface.

Study on Surface Integrity in Hard Milling of Hardened Die Steel

2006 ◽  
Vol 532-533 ◽  
pp. 540-543 ◽  
Author(s):  
Lu Lu Jing ◽  
Gang Liu ◽  
Ming Chen
Keyword(s):  
Residual Stress ◽  
Tool Wear ◽  
Surface Integrity ◽  
Cutting Tools ◽  
Longitudinal Direction ◽  
Negative Influence ◽  
Practical Significance ◽  
Hard Milling ◽  
Machined Surface ◽  
Die Steel

In die and mold industry, there is a tendency to use milling in the finishing machining of dies and molds as an alternative to the traditional EDM process, consequently the surface integrity in milling is considered as one of the most important indices. In this study, surface roughness, micrograph of machined surface, surface microhardness, residual stress, and metallurgical texture of the surface layer were considered. The influence of geometrical characteristics of cutting tools and tool wear on surface integrity was studied. The results showed that hard milling of hardened die steel could yield a quite satisfied surface integrity by proper process; compressive residual stress was induced on machined surface, and the compressive stress induced in transversal direction was almost 3 times of that in longitudinal direction; tool wear had a significant negative influence on surface finish and caused the machined surface soften. These conclusions revealed the effects of tool conditions on surface integrity and would play a practical significance in the machining of hardened die steel.

scholarly journals Effect of Machined Surface Integrity on Fatigue Performance of Metal Workpiece: A Review

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Guoliang Liu ◽  
Chuanzhen Huang ◽  
Bin Zhao ◽  
Wei Wang ◽  
Shufeng Sun
Keyword(s):  
Residual Stress ◽  
Surface Topography ◽  
Surface Integrity ◽  
Work Hardening ◽  
Fatigue Cracks ◽  
Fatigue Performance ◽  
Effective Control ◽  
Published Data ◽  
Machined Surface ◽  
Machined Surface Integrity

AbstractFatigue performance is a serious concern for mechanical components subject to cyclical stresses, particularly where safety is paramount. The fatigue performance of components relies closely on their surface integrity because the fatigue cracks generally initiate from free surfaces. This paper reviewed the published data, which addressed the effects of machined surface integrity on the fatigue performance of metal workpieces. Limitations in existing studies and the future directions in anti-fatigue manufacturing field were proposed. The remarkable surface topography (e.g., low roughness and few local defects and inclusions) and large compressive residual stress are beneficial to fatigue performance. However, the indicators that describe the effects of surface topography and residual stress accurately need further study and exploration. The effect of residual stress relaxation under cycle loadings needs to be precisely modeled precisely. The effect of work hardening on fatigue performance had two aspects. Work hardening could increase the material yield strength, thereby delaying crack nucleation. However, increased brittleness could accelerate crack propagation. Thus, finding the effective control mechanism and method of work hardening is urgently needed to enhance the fatigue performance of machined components. The machining-induced metallurgical structure changes, such as white layer, grain refinement, dislocation, and martensitic transformation affect the fatigue performance of a workpiece significantly. However, the unified and exact conclusion needs to be investigated deeply. Finally, different surface integrity factors had complicated reciprocal effects on fatigue performance. As such, studying the comprehensive influence of surface integrity further and establishing the reliable prediction model of workpiece fatigue performance are meaningful for improving reliability of components and reducing test cost.

Machinability of the EBM Ti6Al4V in Cryogenic Turning

2015 ◽  
Vol 651-653 ◽  
pp. 1183-1188 ◽  
Author(s):  
Stefano Sartori ◽  
Alberto Bordin ◽  
Stefania Bruschi ◽  
Andrea Ghiotti
Keyword(s):  
Tool Wear ◽  
Liquid Nitrogen ◽  
Surface Integrity ◽  
Cutting Temperature ◽  
Chip Morphology ◽  
Cutting Fluid ◽  
Cobalt Chromium ◽  
Machined Surface ◽  
Surgical Implants ◽  
Cutting Zone

In machining operations, the adoption of a cutting fluid is necessary to mitigate the effects of the high temperatures generated on the cutting zone, and, therefore, to avoid severe detrimental effects on the tool wear and surface integrity. In the biomedical field, the traditional processes to manufacture surgical implants made of Titanium and Cobalt Chromium Molybdenum alloys involve turning and milling operations. To cool the cutting tool with standard oil emulsions leaves contaminants on the machined surfaces, which require further cleaning steps that are expensive in terms of time and costs. Currently, this limitation is marginally overcome by machining without the coolant; however, as a consequence, severe tool wear and poor surface integrity take place. In the last years, many studies have been conducted on the application of Liquid Nitrogen as a coolant in machining difficult-to-cut materials such as Ti6Al4V. Thanks to its properties to evaporate immediately when getting in contact with the cutting zone, thus living the workpiece and chips dry and clean other than its ability to lower the cutting temperature. The adoption of Liquid Nitrogen as a cooling mean in machining surgical implants may represent an optimum solution enhancing the benefits of dry machining. This work is aimed at evaluating the performances of the Liquid Nitrogen as a coolant in semi-finishing turning of Ti6Al4V produced by Electron Beam Melting, a comparison with dry turning is presented. The alloy machinability in such conditions is evaluated in terms of tool wear, machined surface integrity and chip morphology.

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