scholarly journals Impact of grinding wheel specification on surface integrity and residual stress when grinding Inconel 718

2020 ◽  
pp. 095440542096120
Author(s):  
David Curtis ◽  
Holger Krain ◽  
Andrew Winder ◽  
Donka Novovic
Keyword(s):  
Residual Stress ◽  
Inconel 718 ◽  
Cubic Boron Nitride ◽  
Grinding Wheel ◽  
Stress Profile ◽  
Standard Equipment ◽  
Residual Stress Profile ◽  
Grinding Parameters ◽  
Stress Formation

The grinding process is often maligned by grinding burn; which refers to many unwanted effects, including residual stress formation. This paper presents an overview of the role of grinding wheel technologies in the surface response and residual stress formation of thin section Inconel 718. Using production standard equipment, conventional abrasive vitrified, and super abrasive electroplated wheel technologies were evaluated in initial comparative trials. Results revealed the dominant residual stress profiles, which manifested as measurable distortion and the thermo-mechanical impact of grinding, such as softening. Following this, a parametric study was carried out using cubic boron nitride super abrasive electroplated wheels to investigate the interaction of grinding parameters on the generated output. It was shown that at increased grinding aggressions, tensile stress regimes increased resulting in increased distortion magnitudes. The study highlights the importance of assessing residual stress formation when manipulating both wheel technologies and grinding parameters. It is envisaged that with additional assessment, a route to an engineered residual stress profile might be achieved.

Effects of process combinations of milling, grinding, and polishing on the surface integrity and fatigue life of GH4169 components

2019 ◽  
Vol 234 (3) ◽  
pp. 538-548
Author(s):  
Fang Quan ◽  
Zhitong Chen ◽  
Qiantong Li ◽  
Shimin Gao
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Boron Nitride ◽  
Compressive Residual Stress ◽  
High Cycle Fatigue ◽  
Cubic Boron Nitride ◽  
Stress Profile ◽  
Cycle Fatigue ◽  
Squeezing Effect ◽  
Residual Stress Profile

The nickel-based superalloy GH4169 is widely applied in the aviation industry due to its outstanding mechanical properties. However, many blades of GH4169 are still produced by milling and manual polishing, which is costly and unreliable. In this article, GH4169 superalloy components manufactured with combination processes of milling, grinding, and polishing were comparatively studied involving surface integrity and fatigue performance. Test results indicate that the final polishing is the most dominant process that influences the high-cycle fatigue life of GH4169 components. Samples produced via cubic boron nitride grinding and numerical control polishing with a diamond-rubber wheel exhibit fatigue limits of 150 MPa higher than the milled and manually polished samples. Cubic boron nitride grinding induces a considerable compressive residual stress profile with a magnitude of -930 MPa and a depth of 200 μm. Milling induces a typical “hook” residual stress profile with 318 MPa at the surface. Polishing affects the machined surface by two ways, the removal effect and the squeezing effect. The squeezing effect induces a shallow compressive residual stress with approximately −1000 MPa, therefore improves the surface condition. However, inevitable omissions, scratches, texture disorders, and knock marks in hand-polishing are the main causes of the unstable high-cycle fatigue life of hand-polished components.

scholarly journals Influence of residual stress profile and surface microstructure on fatigue life of a 15-5PH

2018 ◽  
Vol 213 ◽  
pp. 623-629 ◽  
Author(s):  
F. Valiorgue ◽  
V. Zmelty ◽  
M. Dumas ◽  
V. Chomienne ◽  
C. Verdu ◽  
...  
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Surface Microstructure ◽  
Stress Profile ◽  
Residual Stress Profile

scholarly journals Cross-Sectional Mapping of Residual Stresses by Measuring the Surface Contour After a Cut

2000 ◽  
Vol 123 (2) ◽  
pp. 162-168 ◽  
Author(s):  
M. B. Prime
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Stress Measurement ◽  
Superposition Principle ◽  
New Method ◽  
Contour Method ◽  
Stress Profile ◽  
Relaxation Methods ◽  
Cross Sectional ◽  
Residual Stress Profile

A powerful new method for residual stress measurement is presented. A part is cut in two, and the contour, or profile, of the resulting new surface is measured to determine the displacements caused by release of the residual stresses. Analytically, for example using a finite element model, the opposite of the measured contour is applied to the surface as a displacement boundary condition. By Bueckner’s superposition principle, this calculation gives the original residual stresses normal to the plane of the cut. This “contour method” is more powerful than other relaxation methods because it can determine an arbitrary cross-sectional area map of residual stress, yet more simple because the stresses can be determined directly from the data without a tedious inversion technique. The new method is verified with a numerical simulation, then experimentally validated on a steel beam with a known residual stress profile.

Study of Effect of Repetition Rate on Laser Shock Peening Using Finite Element Modeling

2020 ◽  
Author(s):  
Sai Kosaraju ◽  
Xin Zhao
Keyword(s):  
Shock Wave ◽  
Residual Stress ◽  
Finite Element ◽  
Shock Waves ◽  
Repetition Rate ◽  
High Repetition Rate ◽  
Stress Profile ◽  
Surface Residual Stress ◽  
Residual Stress Profile ◽  
High Repetition

Abstract A two-dimensional finite element model is developed to simulate the interaction between metal samples and laser-induced shock waves. Multiple laser impacts are applied at each location to increase plastically affected depth and compressive stress. The in-depth and surface residual stress profiles are analyzed at various repetition rates and spot sizes. It is found that the residual stress is not sensitive to repetition rate until it reaches a very high level. At extremely high repetition rate (100 MHz), the delay between two shock waves is even shorter than their duration, and there will be shock wave superposition. It is revealed that the interaction of metal with shock wave is significantly different, leading to a different residual stress profile. Stronger residual stress with deeper distribution will be obtained comparing with lower repetition rate cases. The effect of repetition rate at different spot sizes is also studied. It is found that with larger laser spot, the peak compressive residual stress decreases but the distribution is deeper at extremely high repetition rates.

scholarly journals Role of Steel Plate Thickness on the Residual Stress Formation and Cracking Behavior During Flame Cutting

2019 ◽  
Vol 50 (9) ◽  
pp. 4178-4192 ◽  
Author(s):  
Tuomas Jokiaho ◽  
Suvi Santa-aho ◽  
Pasi Peura ◽  
Minnamari Vippola
Keyword(s):  
Residual Stress ◽  
Steel Plate ◽  
Plate Thickness ◽  
Cracking Behavior ◽  
Stress Formation

scholarly journals Parametric Study of Fixtured Vibropeening

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 910 ◽  
Author(s):  
Chan ◽  
Ahluwalia ◽  
Gopinath
Keyword(s):  
Residual Stress ◽  
Process Parameters ◽  
Continuous Treatment ◽  
Optimal Time ◽  
Process Time ◽  
Time Range ◽  
Work Piece ◽  
Stress Profile ◽  
Process Step ◽  
Residual Stress Profile

Vibropeening is a surface treatment process, which combines the peening effect of introducing residual stress with the polishing effect of reducing surface roughness in one single process step. Vibropeening equipment induces vibrations into the media to impart residual compressive stresses in sub-surface layers, as well as polishing on the surface of the work piece. In addition to process parameters, such as vibration frequency, amplitude, and media mass, which are well known in literature, this paper will focus on the study of two additional parameters: immersion depth and process time. It was found that the lower-middle section of the vibratory trough produced the highest Almen deflection. Different continuous treatment times were also studied to explore the maximum introducible residual compressive stress state, and it was concluded that an optimal time range is required to achieve the best residual stress profile. The study demonstrates that different process parameters can influence the effectiveness of the vibropeening process, and that these can be potentially optimized for higher treatment capability.

Influence of customized cutting edge geometries on the workpiece residual stress in hard turning

2017 ◽  
Vol 232 (12) ◽  
pp. 2132-2139 ◽  
Author(s):  
Carlos EH Ventura ◽  
Bernd Breidenstein ◽  
Berend Denkena
Keyword(s):  
Residual Stress ◽  
Compressive Residual Stress ◽  
Hard Turning ◽  
Influence Factors ◽  
Contact Length ◽  
Cutting Edge ◽  
Stress Profile ◽  
Workpiece Surface ◽  
Residual Stress Profile ◽  
Initiation And Propagation

Depending on the intensity of mechanical and thermal loads during hard turning, compressive and/or tensile residual stress can be obtained. However, only compressive residual stress contributes to avoid crack initiation and propagation and increase fatigue life. In order to induce compressive residual stress in the workpiece surface and subsurface, cutting edge geometry is one of the most important influence factors. Taking this into account, the influence of new customized cutting edge geometries on the parameters of a hook-shaped residual stress profile (typical of a hard turning process) is investigated and possible causes for the encountered phenomena are explained. It was found that edge geometries, which provide an increase in contact length between tool and workpiece, lead to higher compressive residual stress in the subsurface and deeper affected zones.

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