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.

Peripheral milling-induced residual stress and its effect on tensile–tensile fatigue life of aeronautic titanium alloy Ti–6Al–4V

2019 ◽  
Vol 123 (1260) ◽  
pp. 212-229 ◽  
Author(s):  
Dong Yang ◽  
Xiao Xiao ◽  
Yulei Liu ◽  
Jing Sun
Keyword(s):  
Residual Stress ◽  
Titanium Alloy ◽  
Fatigue Life ◽  
Surface Energy ◽  
Compressive Residual Stress ◽  
Cutting Speed ◽  
Depth Of Cut ◽  
Stress Profile ◽  
Peripheral Milling ◽  
Residual Stress Profile

ABSTRACTThe special application environment puts forward the higher requirement of reliability of parts made from titanium alloy Ti–6Al–4V, which is closely related to the machining-induced residual stress. For the fact of the non-linear distribution of residual stress beneath the machined surface, distribution of peripheral milling-induced residual stress and its effect on fatigue performance of titanium alloy Ti–6Al–4V are still confusing. In the present study, residual stress profile induced by peripheral milling of Ti–6Al–4V is first studied. And then, energy criteria are proposed to characterise the whole state of the residual stress field. Finally, the effects of residual stress profile and surface energy on tensile–tensile fatigue performance of titanium alloy Ti–6Al–4V are discussed. The conclusions were drawn that the variation trend of surface residual stress (σr,Sur), maximum compressive residual stress (σC,ax), location (hr0) and response depth (hry) of residual stress profile with cutting parameters showed a similar pattern for both measure directions those parallel (σ1) and perpendicular (σ3) to the cutting direction. Cutting speed and feed rate have a main effect on surface residual stress, and the depth of cut has little effect on all the four key factors of residual stress profile. With the increase of cutting speed and feed rate, machining-induced surface energy tends to become larger. But increasing the depth of cut caused the strain energy stored in unit time to decrease. Furthermore, the effect of depth of cut on surface energy was weakened when the value of cutting depth becomes larger. Both the surface compressive residual stress and the maximum compressive residual stress are beneficial for prolonging the fatigue life, while large value of machining-induced surface energy leads to a decrease of fatigue life. Analysis of variance result shows that maximum residual compressive stress has a greater impact on fatigue life than other residual stress factors.

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 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.

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.

scholarly journals High cycle fatigue analysis in the presence of autofrettage compressive residual stress

2018 ◽  
Vol 41 (11) ◽  
pp. 2305-2320
Author(s):  
V. Okorokov ◽  
D. MacKenzie ◽  
Y. Gorash ◽  
M. Morgantini ◽  
R. van Rijswick ◽  
...  
Keyword(s):  
Residual Stress ◽  
Compressive Residual Stress ◽  
High Cycle Fatigue ◽  
Fatigue Analysis ◽  
Cycle Fatigue

The Effects of Process-Induced Residual Stress on Rolling Contact Stress of Hard Machined Components

Manufacturing ◽  
2003 ◽  
Author(s):  
Y. B. Guo ◽  
Mark E. Barkey ◽  
David W. Yen
Keyword(s):  
Residual Stress ◽  
Fatigue Damage ◽  
Compressive Residual Stress ◽  
Hard Turning ◽  
Stress Pattern ◽  
Rolling Contact ◽  
Small Scale ◽  
Stress Profile ◽  
Residual Stress Profile ◽  
Significant Difference

Compared with grinding, hard turning is a competitive manufacturing process that in many cases has substantial benefits. The most significant difference between hard turning and grinding is that hard turning may induce a relatively deep compressive residual stress. However, the interactions among the residual stress profile, applied load, and surface material, and their effects on component life in rolling contact are poorly understood. Further, contact stresses and strains are difficult to measure using the current experimental techniques due to the small-scale of the phenomena. A new simulation model of rolling contact has been developed to account for a process-induced residual stress profile. It has shown that distinct residual stress patterns hardly affect neither the magnitudes nor the locations of peak stresses and strains below the surface. However, they have a significant influence on surface deformations. The slope and depth of a compressive residual stress profile are key factors for rolling contact fatigue damage, which was substantiated by the available experimental data. Equivalent plastic strain could be a parameter to characterize the relative fatigue damage. The magnitudes of process-induced residual stress are reduced in rolling contact. The predicted residual stress pattern and magnitude agree with the test data in general. In addition, rolling contact is more sensitive to normal load and residual stress pattern than tangential load.

Hook Shaped Residual Stress: The Effect of Tool Ploughing, and the Analysis of the Mechanical and Thermal Effects

2012 ◽  
Author(s):  
Xueping Zhang ◽  
Shenfeng Wu ◽  
C. Richard Liu
Keyword(s):  
Residual Stress ◽  
Formation Process ◽  
Chip Formation ◽  
Thermal Effects ◽  
Thermal Load ◽  
Compressive Residual Stress ◽  
Mechanical Load ◽  
Stress Profile ◽  
Fe Model ◽  
Residual Stress Profile

To investigate the unique hook-shaped residual stress profile generated from hard turning process, an improved orthogonal (2-D) Finite Element (FE) model is established to include the ploughing effect of cutting edge. The model is further decomposed into two FE sub-models (sub-model 1 and sub-model 2) to determine the thermal and mechanical effects on the residual stress profiles by saw-tooth chip formation process and honed-edge ploughing process respectively. The two FE sub-models are sequentially adopted to evaluate the compression effect induced by chip formation process and ploughing effect resulted from honed-edge cutting tool on residual stress profile. Their separated and integrated effects on residual stress hook-shape profile are addressed by comparing the predicted residual stresses by sub-model 1, sub-model 2, the two sub-models’ superposition, and the whole improved FE model. The results show that chip formation effect on residual stress profile happens earlier than the ploughing effect. Chip formation effect provides a foundation for the finalized residual stress profile by determining the maximum depth and magnitude of the compressive residual stress. Ploughing process generates much more thermal load to produce the tensile residual stress in hard turned surface and sequentially drives the final resultant residual stress into an obvious hook-shaped by modifying the previous compressive residual stress profile. The location with the maximum compressive residual stress is identified as the critical position to separate the mechanical load and thermal load generated from ploughing effect. The decomposition methodology on mechanical and thermal effects is proposed and thoroughly discussed in the paper.

Neutron Determination of Residual Stress in a Nitrided Notched Part

2005 ◽  
Vol 490-491 ◽  
pp. 251-256 ◽  
Author(s):  
Agnès Fabre ◽  
Laurent Barrallier
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Thermomechanical Treatment ◽  
Gear Tooth ◽  
Stress Profile ◽  
Residual Stress Profile ◽  
Improve Fatigue

Nitriding is an hardening thermomechanical treatment generally used to improve fatigue life of steel parts, like gear for example. Another effect of this treatment is generating superficial stress, influenced by nitriding conditions, composition of steel and geometry of the part. This work deals with the effect of shape on the residual stress profile obtain after nitriding on a gear tooth. The residual stress profile was determined using neutrons diffraction technique.

High-Cycle Fatigue Strength and Residual Stress in Welded Joints of Structural Steels

2004 ◽  
Author(s):  
Masahito Mochizuki ◽  
Masao Toyoda
Keyword(s):  
Residual Stress ◽  
Phase Transformation ◽  
Fatigue Strength ◽  
Low Temperature ◽  
Weld Metal ◽  
Welded Joints ◽  
Compressive Residual Stress ◽  
High Cycle Fatigue ◽  
Temperature Phase ◽  
Cycle Fatigue

Improvement of high-cycle fatigue strength by reducing residual stress in welded joints is studied in this paper. 10% Nickel and 10% Chromium are involved in the developed welding material for producing the property of thermal shrinkage by martensitic phase transformation at a low temperature and for generating compressive residual stress during cooling process. A cruciform fillet-welded joint is used for the numerical simulation of the thermal elastic-plastic finite-element analysis with coupling phase transformation effect. Distribution of the computed residual stress agrees with the measuring values by strain gauge. Compressive residual stress mostly distributes in the weld metal for both longitudinal and transverse directions with weld line. Fatigue test is also performed in order to clarify the effect of the developed weld material on fatigue strength. Developed weld metal has much higher characteristics for high-cycle fatigue strength than a conventional one. Increase effect of fatigue strength is shown by the modified Goodman diagram when residual stress is treated as mean stress. Weld metal with the property of low-temperature phase transformation is effective to reduce residual stress and to improve fatigue strength.

Effects of Laser Peening Treatment on High Cycle Fatigue and Crack Propagation Behaviors in Austenitic Stainless Steel

2009 ◽  
Author(s):  
Yasuo Ochi ◽  
Kiyotaka Masaki ◽  
Takashi Matsumura ◽  
Takaaki Ikarashi ◽  
Yuji Sano
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Surface Layer ◽  
Fatigue Crack ◽  
Fatigue Strength ◽  
Crack Propagation ◽  
Compressive Residual Stress ◽  
High Cycle Fatigue ◽  
Laser Peening ◽  
Cycle Fatigue

Laser peening without protective coating (LPwC) treatment is one of surface enhancement techniques using impact wave of high pressure plasma induced by laser pulse irradiation. One of the effects of the LPwC treatment is expected to reduce the tensile residual stress and to induce the compressive residual stress in the surface layer of metallic materials. As a laser has no reaction force due to irradiation and also it has easy characteristics for remote control, the LPwC treatment is practically used as a technique for preventing the stress corrosion cracking (SCC) and for improving the fatigue strength of some structural materials. In this study, high cycle fatigue tests with four-points rotating bending loading were carried out on the non-peened and the LPwC treated low-carbon type austenitic stainless steel 316L in order to investigate the effects of the LPwC treatment on the high cycle fatigue strength and the surface fatigue crack propagation behavior. Two types of specimens were prepared; one was a smooth specimen, the other was a specimen with a pre-crack by the fatigue loading from a small artificial hole. As the results of the LPwC treatment, the high compressive residual stress was induced in the surface layer on the specimens, and the region of the compressive residual stress was about 1mm depth from the surface. The fatigue strength of the LPwC treated SUS316L was remarkably improved during the whole regime of the fatigue life up to the 108 cycles compared with the non-peened materials. Through the fracture mechanics investigation of the pre-cracked materials after the LPwC treatment, it became clear that the fatigue crack propagation was restrained by the LPwC treatment on the pre-cracked region, when the stress intensity factor range ΔK on the crack tip was under the value of 7.6 MPa√m.

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