scholarly journals Investigation of the effect of residual stresses in the subsurface on process forces for consecutive orthogonal cuts

2021 ◽  
Author(s):  
F. Wöste ◽  
J. Kimm ◽  
J. A. Bergmann ◽  
W. Theisen ◽  
P. Wiederkehr
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Electron Backscatter Diffraction ◽  
Orthogonal Cutting ◽  
Empirical Modeling ◽  
Process Forces ◽  
Machined Parts ◽  
Related Stress ◽  
Machining Operations ◽  
Backscatter Diffraction

AbstractThe quality and surface integrity of machined parts is influenced by residual stresses in the subsurface resulting from cutting operations. These stress characteristics can not only affect functional properties such as fatigue life, but also the process forces during machining. Especially for orthogonal cutting as an appropriate experimental analogy setup for machining operations like milling, different undeformed chip thicknesses cause specific residual stress formations in the subsurface area. In this work, the process-related depth profile of the residual stress in AISI 4140 was investigated and correlated to the resulting cutting forces. Furthermore, an analysis of the microstructure of the cut material was performed, using additional characterization techniques such as electron backscatter diffraction and nanoindentation to account for subsurface alterations. On this basis, the influence of process-related stress profiles on the process forces for consecutive orthogonal cutting strategies is evaluated and compared to the results of a numerical model. The insights obtained provide a basis for future investigations on, e. g., empirical modeling of process forces including the influence of process-specific characteristics such as residual stress.

Instability Parameter for Machined Parts

1983 ◽  
Vol 105 (3) ◽  
pp. 133-136 ◽  
Author(s):  
A. Israeli ◽  
J. Benedek
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Single Point ◽  
Machining Parameters ◽  
Machining Processes ◽  
Etching Technique ◽  
Parametric Relationship ◽  
Machined Parts ◽  
Instability Parameter ◽  
Stress Profiles

The production of precision parts requires manufacturing processes which produce low residual stresses. This study was designed to investigate the parametric relationship between machining processes and residual stress distribution. Sets of steel specimens were single point turned at different feeds. The residual stress profiles of these specimens were monitored, using a continuous etching technique. A “Specific Instability Potential” parameter, derived from the strain energy of the residual stresses, was found to relate directly to the machining parameters. It is suggested that the Specific Instability Potential can be used as a parameter for specifying processing operations.

scholarly journals Diffracting-grain identification from electron backscatter diffraction maps during residual stress measurements: a comparison between the sin2ψ and cosα methods

2019 ◽  
Vol 52 (4) ◽  
pp. 828-843 ◽  
Author(s):  
Dorian Delbergue ◽  
Damien Texier ◽  
Martin Lévesque ◽  
Philippe Bocher
Keyword(s):  
Residual Stress ◽  
Grain Size ◽  
Tilt Angle ◽  
Measurement Errors ◽  
Electron Backscatter Diffraction ◽  
Measurement Techniques ◽  
Single Exposure ◽  
X Ray ◽  
Electron Backscatter ◽  
Backscatter Diffraction

X-ray diffraction (XRD) is a widely used technique to evaluate residual stresses in crystalline materials. Several XRD measurement methods are available. (i) The sin2ψ method, a multiple-exposure technique, uses linear detectors to capture intercepts of the Debye–Scherrer rings, losing the major portion of the diffracting signal. (ii) The cosα method, thanks to the development of compact 2D detectors allowing the entire Debye–Scherrer ring to be captured in a single exposure, is an alternative method for residual stress measurement. The present article compares the two calculation methods in a new manner, by looking at the possible measurement errors related to each method. To this end, sets of grains in diffraction condition were first identified from electron backscatter diffraction (EBSD) mapping of Inconel 718 samples for each XRD calculation method and its associated detector, as each method provides different sets owing to the detector geometry or to the method specificities (such as tilt-angle number or Debye–Scherrer ring division). The X-ray elastic constant (XEC) ½S 2, calculated from EBSD maps for the {311} lattice planes, was determined and compared for the different sets of diffracting grains. It was observed that the 2D detector captures 1.5 times more grains in a single exposure (one tilt angle) than the linear detectors for nine tilt angles. Different XEC mean values were found for the sets of grains from the two XRD techniques/detectors. Grain-size effects were simulated, as well as detector oscillations to overcome them. A bimodal grain-size distribution effect and `artificial' textures introduced by XRD measurement techniques are also discussed.

FEM Simulation of the Residual Stress in the Machined Surface Layer for High-Speed Machining

2006 ◽  
Vol 315-316 ◽  
pp. 140-144 ◽  
Author(s):  
Su Yu Wang ◽  
Xing Ai ◽  
Jun Zhao ◽  
Z.J. Lv
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Surface Layer ◽  
Residual Stresses ◽  
High Speed ◽  
Metal Cutting ◽  
Orthogonal Cutting ◽  
High Speed Machining ◽  
Machined Surface ◽  
Cutting Model

An orthogonal cutting model was presented to simulate high-speed machining (HSM) process based on metal cutting theory and finite element method (FEM). The residual stresses in the machined surface layer were obtained with various cutting speeds using finite element simulation. The variations of residual stresses in the cutting direction and beneath the workpiece surface were studied. It is shown that the thermal load produced at higher cutting speed is the primary factor affecting the residual stress in the machined surface layer.

scholarly journals Residual Stress and Microstructure of a Ti-6Al-4V Wire Arc Additive Manufacturing Hybrid Demonstrator

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 701
Author(s):  
Tatiana Mishurova ◽  
Benjamin Sydow ◽  
Tobias Thiede ◽  
Irina Sizova ◽  
Alexander Ulbricht ◽  
...  
Keyword(s):  
Residual Stress ◽  
Additive Manufacturing ◽  
Residual Stresses ◽  
Structural Integrity ◽  
Hybrid Approach ◽  
Aerospace Applications ◽  
Machined Parts ◽  
Functional Features ◽  
Tool Set ◽  
Wire Arc Additive Manufacturing

Wire Arc Additive Manufacturing (WAAM) features high deposition rates and, thus, allows production of large components that are relevant for aerospace applications. However, a lot of aerospace parts are currently produced by forging or machining alone to ensure fast production and to obtain good mechanical properties; the use of these conventional process routes causes high tooling and material costs. A hybrid approach (a combination of forging and WAAM) allows making production more efficient. In this fashion, further structural or functional features can be built in any direction without using additional tools for every part. By using a combination of forging basic geometries with one tool set and adding the functional features by means of WAAM, the tool costs and material waste can be reduced compared to either completely forged or machined parts. One of the factors influencing the structural integrity of additively manufactured parts are (high) residual stresses, generated during the build process. In this study, the triaxial residual stress profiles in a hybrid WAAM part are reported, as determined by neutron diffraction. The analysis is complemented by microstructural investigations, showing a gradient of microstructure (shape and size of grains) along the part height. The highest residual stresses were found in the transition zone (between WAAM and forged part). The total stress range showed to be lower than expected for WAAM components. This could be explained by the thermal history of the component.

scholarly journals Effect of Cryogenic Treatment on Internal Residual Stresses of Hydrogen-Resistant Steel

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1179
Author(s):  
Fengxiang Shang ◽  
Jinxing Kong ◽  
Dongxing Du ◽  
Zheng Zhang ◽  
Yunhua Li
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Residual Stresses ◽  
Electron Backscatter Diffraction ◽  
Cryogenic Treatment ◽  
Temperature Treatment ◽  
Residual Stress Distribution ◽  
Contour Method ◽  
High Temperature Treatment ◽  
Resistant Steel

To reduce the influence of internal residual stress on the processing deformation of thin-walled hydrogen-resistant steel components, combined aging cryogenic and high-temperature treatment was used to eliminate the residual stress, and the effect of cryogenic process parameters on the initial residual stress of the specimens was compared and analyzed based on the contour method. X-ray diffraction, electron backscatter diffraction, and transmission electron microscopy were used to research the mechanism of the effect of cryogenic treatment on the internal residual stress of the specimen. After forging, the internal residual stress distribution of the hydrogen-resistant steel specimens without aging was characterized by tensile stress on the core and compressive stress on both sides, with a stress amplitude of −350–270 MPa. After compound treatment of -130 °C for 10 h and 350 °C for 2 h, the internal residual stress distribution remained unchanged, and the stresses decreased to −150–100 MPa. The internal residual stresses were reduced by 57%–63% compared with the untreated specimens. The cryogenic treatment did not cause phase transformation and carbide precipitation of the hydrogen-resistant steel material. Instead, grain refinement and dislocation density depletion were the main reasons for the reduction in internal residual stresses in the specimens.

Analytical Model for Prediction of Residual Stress in Dynamic Orthogonal Cutting Process

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Xin-Da Huang ◽  
Xiao-Ming Zhang ◽  
Jürgen Leopold ◽  
Han Ding
Keyword(s):  
Residual Stress ◽  
Mechanistic Model ◽  
Orthogonal Cutting ◽  
Numerical Control ◽  
Cutting Process ◽  
Plastic Strains ◽  
Machined Parts ◽  
Engagement Process ◽  
Cutting Experiment ◽  
Dimension Stability

Residual stress, characteristic of surface integrity, is a great issue in cutting process for its significant effects on fatigue life and dimension stability of the machined parts. From a practical viewpoint, residual stress is generated in a dynamic tool-part engagement process, instead of a process with nominal cutting loads. This is the challenge that we have to handle, so as to achieve better predictive methods than the previously recorded approaches in literatures which ignore the dynamic effects on residual stress. This paper presents an analytical method for the prediction of residual stress in dynamic orthogonal cutting. A mechanistic model of the dynamic orthogonal cutting is provided, considering the indentation effect of the cutting edge during the wave-on-wave cutting process. Following the calculation of plastic strains by incremental analysis in mechanical loading, analytical solution of the residual stress due to distributed plastic strains in half-plane is obtained based on inclusion theory. Without relaxation procedures, the two-dimensional (2D) distribution of residual stress in dynamic cutting process is predicted for the first time. A delicately designed dynamic orthogonal cutting experiment is realized through numerical control (NC) lathe. The periodic residual stress distribution is predicted using the proposed approach, which is then validated against the X-ray diffraction measurements.

Prediction of Residual Stress in Multi-Step Orthogonal Cutting

2015 ◽  
Author(s):  
Yamin Shao ◽  
Omar Fergani ◽  
Torgeir Welo ◽  
Steven Liang
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Fatigue Behavior ◽  
Orthogonal Cutting ◽  
Hardening Behavior ◽  
Model Predictions ◽  
Analytical Algorithm ◽  
Precision Part

The effect of residual stresses on the fatigue behavior as well as the dimensional stability of high precision part is very important. Machining operation consists generally multi-step operations from roughing to finishing. It is therefore critical to predict residual stresses under such configuration. In this paper, an analytical algorithm is proposed to predict the final residual stresses induced by a multi-step machining operation capturing the change of stress state of the workpiece as well as material hardening behavior during the multi-step orthogonal cutting. The model predictions were compared to other work’s finite element method (FEM) predictions.

scholarly journals Effect of Tensile Deformation on Residual Stress of GH4169 Alloy

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1773
Author(s):  
Wenxiang Zhu ◽  
Fei Zhao ◽  
Sheng Yin ◽  
Yuan Liu ◽  
Ronggui Yang
Keyword(s):  
Residual Stress ◽  
Tensile Deformation ◽  
Electron Backscatter Diffraction ◽  
Reduction Rate ◽  
Stress Relief ◽  
X Ray ◽  
Dislocation Movement ◽  
Dislocation Group ◽  
Backscatter Diffraction ◽  
Gh4169 Alloy

In order to reduce the residual stress of the GH4169 alloy, the effect and micro-mechanism of the tensile deformation were studied. The residual stress, dislocation density, and distribution of the GH4169 alloy were analyzed by X-ray residual stress tester, X-ray diffractometer (XRD), and electron backscatter diffraction (EBSD). The results show that: with the increase of tensile deformation, the residual stress relief first increases and then decreases. When the tensile deformation is 3%, the reduction rate of residual stress reaches the maximum, which is 90%. The mechanism of residual stress relief by the tensile treatment is that the dislocation group in the alloy is activated by tensile treatment, and the dislocation distribution in the alloy is more uniform by dislocation movement, multiplication, and annihilation so that the residual stress can be eliminated.

Multiscale measurements of residual strains in a stabilized zirconia layer

2012 ◽  
Vol 45 (5) ◽  
pp. 926-935 ◽  
Author(s):  
Julie Villanova ◽  
Claire Maurice ◽  
Jean-Sébastien Micha ◽  
Pierre Bleuet ◽  
Olivier Sicardy ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Electron Backscatter Diffraction ◽  
Polycrystalline Material ◽  
Biaxial Compression ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
X Ray ◽  
Resolution Electron ◽  
Residual Strains ◽  
Backscatter Diffraction

Residual stresses in a polycrystalline material have been determined experimentally at different length scales using three different techniques, with the aim of obtaining quantitative values. The polycrystalline material used is the electrolyte of solid oxide fuel cells, made of yttria-stabilized zirconia and submitted to a high biaxial compression stress state. Macroscopic measurements were performed using traditional X-ray diffraction with the sin2ψ method. Residual stresses within the grains were determined by the X-ray microdiffraction technique using synchrotron radiation. The variation in the strain within each grain was analysed by high-resolution electron backscatter diffraction. The results are self-consistent and give further information on the relation between strain/stress values and grain orientation, and on intragranular strain variations. These results are very important for the validation of mechanical microscopic constitutive equations.

Sign in / Sign up

Export Citation Format

Share Document