Residual Stress Evaluation in Machined Surfaces of Copper by Molecular Dynamic Simulation

2012 ◽  
Author(s):  
Yachao Wang ◽  
Chunhui Ji ◽  
Jing Shi ◽  
Zhanqiang Liu
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Stress Component ◽  
Cutting Speed ◽  
Rake Angle ◽  
Tangential Direction ◽  
Machining Process ◽  
Depth Of Cut ◽  
Machined Surface ◽  
Machined Surfaces

Residual stresses in machined surfaces are often regarded as a determining factor of component service life. However, little work has been conducted to investigate the distribution of residual stresses in machined surfaces at nano-scale. In this paper, an MD simulation study is performed to study the residual stresses in machined surfaces of single crystal copper by diamond tools. We adopt a fixed cutting speed of 400m/s, vary depth of cut from 0.5nm to 1.5 nm, and change the tool rake angle from −30° to +30°. The results are then compared and discussed in the following aspects. First, it is found that both tool rake angle and depth of cut affect the morphologies of the formed chips, and as well as the cutting force evolution during machining process. Second, the normal residual stress in the tangential direction is more significant and has a clearer pattern than those in other directions for all the simulation cases. As such, the focus of the study is on this particular stress component. Third, with the increase of depth of cut, the maximum tensile residual stress decreases, and the residual stress becomes compressive at a shorter distance into the machined surface. Also, the use of negative rake angle makes the residual stress overall more tensile when closer to surface, and more compressive as the depth into surface further increases. It is actually consistent with traditional metal machining theory. The use of negative tool rake angle requires a larger thrust force, and this in turn overall makes the residual stress more compressive.

Residual Stresses in Prestressed Turning of Nickel-Based Superalloy

2012 ◽  
Vol 271-272 ◽  
pp. 242-246 ◽  
Author(s):  
Rui Tao Peng ◽  
Fang Lu ◽  
Xin Zi Tang ◽  
Yuan Qiang Tan
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Compressive Stress ◽  
Feed Rate ◽  
Cutting Speed ◽  
Residual Compressive Stress ◽  
Machining Process ◽  
Depth Of Cut ◽  
Machined Surface ◽  
Nickel Based Superalloy

Aiming to get appropriate residual compressive stress distribution on machined surface just in the machining process, the technique of prestressed cutting is applied for nickel-based superalloy shafts. This article studies theoretically and experimentally the effect of prestress on the residual stress in the machined surface layer. Prestressed turning tests under the conditions of different prestress, cutting speed, depth of cut and feed rate were carried out, residual stresses were determined via an X-ray diffraction technique. Theoretical result demonstrates that higher prestress leads to more prominent residual compressive stress and validated by experiments, meanwhile measured residual stress profiles indicate that lower cutting speed and lower feed rate lead to more remarkable compressive stress state, contrarily depth of cut shows relatively indistinctive effect.

scholarly journals The prediction of the turned machining induced residual stresses in Ti6Al4V: A Critical Surface Integrity Descriptor

2021 ◽  
Vol 347 ◽  
pp. 00037
Author(s):  
Gary Styger ◽  
Rudolph F Laubscher
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Surface Integrity ◽  
Cutting Speed ◽  
Element Model ◽  
Rake Angle ◽  
Critical Surface ◽  
Machining Parameters ◽  
Machined Surface ◽  
Wide Range

The surface integrity of a turned machined surface is an essential indicator of the fatigue and corrosion performance of a component. A critical descriptor of this property is the residual stress, both on the surface and subsurface of a part. However, experimental determination of vital surface integrity parameters such as surface roughness, hardness, affected microstructure, and residual stresses is costly, time consuming, and involves the destruction of the part. Therefore, prediction of these parameters, such as residual stress versus depth, would be of great value and could aid in the correct machining parameters (cutting speed, feed rate, edge tool radius, rake angle, coolant) for the desired part performance. A study was initiated to determine the influence of a worn tool and multiple cuts on a wide range of cutting speeds on residual stresses induced by machining an outside-turned bar of Ti6Al4V titanium alloy. Thus, a project was initiated to develop a non-linear finite element model to predict the residual stresses thus developed due to the machining manufacturing process.

Experimental and FEM Analysis of Cutting Sequence on Residual Stresses in Machined Layers of AISI 316L Steel

2006 ◽  
Vol 524-525 ◽  
pp. 179-184 ◽  
Author(s):  
J.C. Outeiro ◽  
Domenico Umbrello ◽  
Rachid M'Saoubi
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Residual Stresses ◽  
Cutting Speed ◽  
Residual Stress Distribution ◽  
Depth Of Cut ◽  
Aisi 316L ◽  
Machined Surface ◽  
316L Steel ◽  
Cutting Sequence

The reliability of a mechanical component depends to a large extent on the physical state of its surface layers. This state includes the distribution of residual stresses induced by machining. Residual stresses in the machined surface and subsurface are affected by the cutting tool, work material, contact conditions on the interfaces, cutting regime parameters (cutting speed, feed and depth of cut), but also depends on the cutting procedure. In this paper, the effects of cutting sequence on the residual stress distribution in the machined surface of AISI 316L steel are experimentally and numerically investigated. In the former case, the X-ray diffraction technique is applied, while in the latter an elastic-viscoplastic FEM formulation is implemented. The results show that sequential cut tends to increase superficial residual stresses. A greater variation in residual stresses is observed between the first and the second cut. Moreover, an increase in the thickness of the tensile layer is also observed with the number of cuts, this difference also being greater between the first and the second cut. Based on these results, the residual stress distribution on the affected machined layers can be controlled by optimizing the cutting sequence.

Performance assessment of energy efficient and eco-friendly turning of Nimonic C-263: A comparative study on MQL and cryogenic machining

2021 ◽  
pp. 095440542110619
Author(s):  
Prashant S Jadhav ◽  
Chinmaya P Mohanty
Keyword(s):  
Work Environment ◽  
Manufacturing Industry ◽  
Cutting Speed ◽  
Machining Process ◽  
Depth Of Cut ◽  
Work Piece ◽  
Cryogenic Machining ◽  
Machined Surface ◽  
Machining Strategies ◽  
The Impact

Nimonic C-263 is predominantly used in the manufacturing of heat susceptible intricate components in the gas turbine, aircraft, and automotive industries. Owing to its high strength, poor thermal conductivity, the superalloy is difficult to machine and causes rapid tool wear during conventional machining mode. Moreover, the unpleasant machining noise produced during machining severely disrupts the tool engineer’s concentration, thereby denying a precise and environment friendly machining operation. Hence, close dimensional accuracy, superior machined surface quality along with production economy, and pleasant work environment for the tool engineers is the need of an hour of the current manufacturing industry. To counter such issues, the present work attempts to compare and explore the machinability of two of the most popular machining strategies like minimum quantity lubrication (MQL) and cryogenic machining process during turning of Nimonic C-263 work piece in order to achieve an ideal machining environment. The machining characteristics are compared in terms of surface roughness (SR), power consumption (P), machining noise (S), nose wear (NW), and cutting forces (CF) to evaluate the impact of machining variables like cutting speed (Vc), feed (f), and depth of cut (ap) with a detailed parametric study and technical justification. Yet again, an investigation is conducted to compare both the machining strategies in terms of qualitative responses like chip morphology, total machining cost, and carbon emissions. The study revealed that cryogenic machining strategy is adequately proficient over MQL machining to deliver energy proficient and gratifying work environment for the tool engineers by reducing the cost of machining and improving their work efficiency.

A Numerical Study on the Redistribution of Residual Stress After Machining

2017 ◽  
Author(s):  
Kunyang Lin ◽  
Wenhu Wang ◽  
Ruisong Jiang ◽  
Yifeng Xiong
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Residual Stresses ◽  
Numerical Study ◽  
Cutting Speed ◽  
Machining Process ◽  
Stress Profile ◽  
Residual Stress Field ◽  
Machining Processes ◽  
Residual Stress Profile

Machining induced residual stresses have an important effect on the surface integrity. Effects of various factors on the distribution of residual stress profiles induced by different machining processes have been investigated by many researchers. However, the initial residual, as one of the important factor that affect the residual stress profile, is always been ignored. In this paper, the residual stress field induced by the quenching process is simulated by the FEM software as the initial condition. Then the initial residual stress field is used to study the residual stress redistribution after the machining process. The influence of initial stress on the stress formation is carried out illustrating with the mechanical and thermal loads during machining processes. The effects of cutting speed on the distribution of residual stress profile are also discussed. These results are helpful to understand how initial residual stresses are redistributed during machining better. Furthermore, the results in the numerical study can be used to explain the machining distortion problem caused by residual stress in the further work.

Local Residual Stress Distribution at the Tooth Root Surface of a Broached Steel Component

2012 ◽  
Vol 706-709 ◽  
pp. 1731-1736 ◽  
Author(s):  
Tobias Strauss ◽  
Harald Meier ◽  
Jens Gibmeier ◽  
Volker Schulze ◽  
Alexander Wanner
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Cutting Forces ◽  
Cutting Speed ◽  
Surface Hardness ◽  
Case Hardening ◽  
Dry Cutting ◽  
Machined Surface ◽  
Near Surface ◽  
Case Hardening Steel

Broaching is an important technique for creating tooth structures in mechanical components. In the present work, the effects of the broaching process on the material state in the near surface region at the root of the tooth was analyzed. The studies were carried out on broached plates made from case hardening steel SAE 5120. The cutting speed and machining condition (cooling lubricant, dry machining) were varied. During broaching with a TiAlN coated tool the cutting forces were monitored. Subsequently, the local residual stresses at the root of the tooth were determined using X-ray diffraction. Further, surface roughness and micro hardness measurements as well as microstructure analysis complement the results. The results indicate that cutting forces have a high influence on the development of the residual stress state at the machined surface whereas no significant effect on changes in surface hardness and microstructure could be observed. Dry cutting with relatively high cutting speeds (≥ 30m/min) result in low cutting forces and hence in high tensile residual stresses in broaching direction.

scholarly journals Effect of Cutting Conditions on the Residual Stresses Induced by Milling of AISI 1045 Steel

2019 ◽  
Vol 8 (2) ◽  
pp. 1462-1465 ◽  
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Diffraction Method ◽  
Cutting Conditions ◽  
Depth Of Cut ◽  
Machining Processes ◽  
Machined Surface ◽  
Aisi 1045 Steel ◽  
Aisi 1045 ◽  
1045 Steel

The nature of residual stresses caused by machining processes has been relevant to the study of component performance for decades. The concept that cutting parameters affect the magnitude and nature of residual stress is well known. In order to reduce the residual stresses on a machined surface, it is important to identify the extent of the effect of cutting conditions. This paper presents the effect of depth of cut and tool speed on milling induced residual stresses. Speed and depth of cut were varied when milling several AISI 1045 Steel specimens. Stresses were measured with the X-ray diffraction method and corroborated with mathematical modelling on an FEA software. A relationship between tool speed and residual stress, and depth of cut and residual stress was thus obtained.

Minimized Wear and Debris Generation Through Optimized Machining of Co-Cr-Mo Alloys for Use in Metal-on-Metal Hip Implants

2012 ◽  
Author(s):  
Ashish Deshpande ◽  
Shu Yang ◽  
Dave Puleo ◽  
David Pienkowski ◽  
Oscar Dillon ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Wear Debris ◽  
Wear Behavior ◽  
Cutting Speed ◽  
Machining Process ◽  
Depth Of Cut ◽  
Machining Parameters ◽  
Machining Conditions ◽  
Metal On Metal ◽  
Tool Edge

More than 380,000 hips are replaced with total joint prostheses each year in the U.S. Wear debris generated by metal-on-metal implant designs is of concern due to potential adverse biological effects arising from chronic exposure of human tissue to the wear debris. This paper presents a new methodology for optimizing the wear performance of prosthesis made of Co-Cr-Mo alloys by varying tool edge geometry and machining conditions to alter the wear behavior of this alloy, while also controlling the residual stresses induced during the machining process. The machining process causes inhomogeneous inelastic deformations near the surface layer of machined parts which create residual stresses in the surface of machined components. Residual stresses in the machined surface and the subsurface are affected by cutting tool material, tool geometry, workpiece, tool-work interface conditions, and the cutting parameters such as feed rate, depth of cut and cutting speed. In the current work, residual stresses were measured using X-ray diffraction technique (XRD). The surface residual stresses in two directions (radial and hoop) were measured on the machined pins after machining with different machining conditions, but prior to the wear test. Wear behavior of Co-Cr-Mo alloy pin specimens, produced from machining with varying tool edge geometry and machining conditions, was studied using a custom-made biaxial motion pin-on-disc tribological testing system in which the pin specimen is immersed in a simulated bio-fluid environment. Wear-induced weight loss (± 10 μg) and changes in surface roughness (± 0.001 μm) were obtained at 100,000 cycle intervals upto 500,000 cycles. Metallographic analysis was performed on the machined pin specimens to analyze the microstructure and microhardness before and after testing. The rate of wear for the specimens was lowest for those pins where the change of the subsurface microhardness was small due to prevention of additional steady state wear after the initial run-in wear in the wear tester. A combination or response surface methodology and genetic algorithm (GA) was used in to optimize the various machining parameters for minimized wear generation. The optimal combination of the four machining parameters (feed 0.18mm/rev, nose radius 0.6 mm, cutting speed 27.6 m/min and depth of cut 0.38) produced the largest compressive residual stresses on the surface and subsurface of the implants thereby reducing the wear/debris generation by about fifty percent.

Surface Intergrity of Inconel 718 under MQL Condition

2010 ◽  
Vol 150-151 ◽  
pp. 1667-1672 ◽  
Author(s):  
Che Hassan Che Haron ◽  
Jaharah Abd Ghani ◽  
Mohd Shahir Kasim ◽  
T.K. Soon ◽  
Gusri Akhyar Ibrahim ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Feed Rate ◽  
Inconel 718 ◽  
Cutting Speed ◽  
Machining Process ◽  
Graphical Form ◽  
Depth Of Cut ◽  
Optimum Process ◽  
Machined Surface ◽  
Coated Carbide

The purpose of this study is to investigate the effect of turning parameters on the surface integrity of Inconel 718. The turning parameters studied were cutting speed of 90, 120, 150 m/min, feed rate of 0.15, 0.25, 0.25mm/rev and depth of cut of 0.3, 0.4, 0.5 mm under minimum quantity lubricant (MQL) using coated carbide tool. surface response methodology (RSM) design of experiment using Box-Behnken approach has been employed consisting of various combination of turning parameters Surface roughness, surface topography, microstructure and the micro hardness of the machined surface were studied after the machining process. Feed rate was found to be the most significant parameter affecting the surface roughness. The optimum parameter was obtained with Ra equal to 0.243 µm at cutting speed of 150 m/min, feed rate of 0.25 mm/rev and depth of cut of 0.3mm. A mathematical model for surface roughness was developed using Response Surface Methodology. The effect of turning parameters and factor interactions on surface roughness is presented in 3D graphical form, which helps in selecting the optimum process parameters to achieve the desired surface quality.

Surface Integrity of Die Material in High Speed Hard Machining, Part 2: Microhardness Variations and Residual Stresses

1999 ◽  
Vol 122 (4) ◽  
pp. 632-641 ◽  
Author(s):  
T. I. El-Wardany ◽  
H. A. Kishawy ◽  
M. A. Elbestawi
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Residual Stresses ◽  
High Speed ◽  
Residual Stress Distribution ◽  
Depth Of Cut ◽  
Hard Machining ◽  
Machined Surface ◽  
Workpiece Surface

The main objective of this paper is to investigate the quality and integrity of the surface produced during high speed hard machining (HSHM) of D2 tool steel in its hardened state (60–62 HRc). Polycrystalline Cubic Boron Nitride (PCBN) tools are used in this study. The results obtained from the micro-graphical analysis of the surface produced are presented in Part 1 of this paper. In Part 2 micro-hardness and residual stress analyses are presented. Microhardness measurements are conducted beneath the machined surface. X-ray diffraction analysis is performed to obtain the residual stress distribution beneath the surface. Analytically, a 3-D thermo-elasto-plastic finite element model is developed to predict the residual stresses induced in the workpiece surface. In the model the cutting zone is specified based on the tool condition (i.e., sharp or worn). The finite element analysis demonstrates the significant effect of the heat generated during cutting on the residual stress distribution. The results illustrate the possibility of minimizing the high tensile residual stresses produced in the workpiece surface, by selecting the appropriate depth of cut. A good correlation between the analytical and predicted residual stress is obtained. [S1087-1357(00)00804-2]

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