Analytical and Numerical Predictions of Machining-Induced Residual Stress in Milling of Inconel 718 Considering Dynamic Recrystallization

2018 ◽  
Author(s):  
Yixuan Feng ◽  
Zhipeng Pan ◽  
Xiaohong Lu ◽  
Steven Y. Liang
Keyword(s):  
Residual Stress ◽  
Grain Size ◽  
Flow Stress ◽  
Dynamic Recrystallization ◽  
Analytical Model ◽  
Inconel 718 ◽  
Milling Process ◽  
Stress Profile ◽  
Recrystallization Process ◽  
Numerical Predictions

A new analytical model is proposed to predict the residual stress in the milling process of Inconel 718 based upon the mechanics analysis of microstructural evolutions. The model proposes to quantify the effects of dynamic recrystallization process on the material flow stress under combined thermal-mechanical loadings in machining. Physics-based mechanistic model is applied to predict the percentage of dynamic recrystallization and the grain size as functions of the milling process parameters and materials constative attributes. The variation of grain size is expected to alter the yield stress, and such dependency relationship is applied to predict the flow stress, which is also dependent on strain, strain rate, and temperature. The time-varying trajectory of residual stress is then predicted at each milling rotation angle through the transformation from milling to equivalent orthogonal cutting, the calculation of stress distribution in loading process, and the stress change during relaxation. The results of analytical model are validated through numerical prediction. The residual stress profile predicted by proposed analytical model matches better with results from numerical model comparing with model without consideration of dynamic recrystallization, especially within subsurface area, with improved accuracy of peak compressive residual stress prediction.

Turning Force Prediction of AISI 4130 Considering Dynamic Recrystallization

2017 ◽  
Author(s):  
Zhipeng Pan ◽  
Yixuan Feng ◽  
Xia Ji ◽  
Steven Y. Liang
Keyword(s):  
Grain Size ◽  
Flow Stress ◽  
Dynamic Recrystallization ◽  
Analytical Model ◽  
Cutting Forces ◽  
Material Flow ◽  
Explicit Calculation ◽  
Material Microstructure ◽  
Machining Forces ◽  
Aisi 4130

Thermal mechanical loadings in machining process would promote material microstructure changes. The material microstructure evolution, such as grain size evolution and phase transformation could significantly influence the material flow stress behavior, which will directly affect the machining forces. An analytical model is proposed to predict cutting forces during the turning of AISI 4130 steel. The material dynamic recrystallization is considered through Johnson-Mehl-Avrami-Kolmogorov (JMAK) model. The explicit calculation of average grain size is provided in an analytical model. The grain size effect on the material flow stress is considered by introducing the Hall-Petch relation into a modified Johnson-Cook model. The cutting forces prediction are based on Oxley’s contact mechanics with consideration of mechanical and thermal loads. The model is validated by comparing the predicted machining forces with experimental measurements.

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.

Flow Stress Behavior of Nanometric Al2O3 Particulate Reinforced Al Alloy Composites Manufactured by Casting

2012 ◽  
Vol 430-432 ◽  
pp. 1294-1297
Author(s):  
Zhi Min Zhang ◽  
Yong Biao Yang ◽  
Xing Zhang
Keyword(s):  
Grain Size ◽  
Flow Stress ◽  
Dynamic Recrystallization ◽  
Al Alloy ◽  
Strain Rates ◽  
Stress Behavior ◽  
Flow Stress Behavior ◽  
Increasing Temperature ◽  
Particulate Reinforced ◽  
Temperature Dynamic

The flow stress behavior of nanometric Al2O3 particulate reinforced Al alloy composites were investigated using thermal simulation machine Gleeble-1500. Microsturctural analysis were carried out on optical microscopy. The results showed that the flow stress increased with increasing strain rate and decreased with decreasing temperature. Dynamic recovery and dynamic recrystallization occurred during hot compression of the Al composites. The grain size increased with increasing temperature (590k-710k) and decreased at 750k due to dynamic recrystallization. The grain size decreased with increasing strain rates at 750k.

Residual Stress Regenerated on Low Plasticity Burnished Inconel 718 Surface After Initial Turning Process

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Yang Hua ◽  
Zhanqiang Liu ◽  
Bing Wang ◽  
Jiaming Jiang
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Analytical Model ◽  
Inconel 718 ◽  
Plastic Behavior ◽  
Residual Stress Field ◽  
Workpiece Material ◽  
Elastic Plastic ◽  
Initial Residual Stress ◽  
Low Plasticity Burnishing

Abstract Low plasticity burnishing (LPB) has been extensively employed in aero-industry to enhance fatigue performance of machined components by introducing compressive residual stress. Effects of various parameters on the residual stress field induced by low plasticity burnishing have been investigated by many researchers. However, initial residual stresses induced by machining are one of the important factors which affect the residual stress regenerated by the LPB process. The present work aims to develop an analytical model which takes into account the initial residual stress and burnishing parameters to predict residual stress field of workpiece material Inconel 718 based on Hertz contact theory and elastic–plastic theory. Initial residual stress fields were produced by turning of Inconel 718 and were measured by using X-ray diffraction technique. Two types of material constitutive models such as the linear hardening model and isotropic–kinematic model were employed to describe the elastic–plastic behavior of workpiece material Inconel 718. An analytical study was performed to analyze the effect of the initial residual stress field and burnishing parameters on residual stress induced by low plastic burnishing. The results of analytical model were verified by conducting the LPB experiments on initial turned Inconel 718. The results showed that the shape and magnitude of the residual stress field obtained with considering the effect of initial residual stress field was in good accordance with experimental measurements.

Prediction of Surface Hardness in Laser-Assisted Milling

2019 ◽  
Author(s):  
Yixuan Feng ◽  
Tsung-Pin Hung ◽  
Yu-Ting Lu ◽  
Yu-Fu Lin ◽  
Fu-Chuan Hsu ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Grain Size ◽  
Predictive Model ◽  
Work Hardening ◽  
Surface Hardness ◽  
Size Variation ◽  
Milling Process ◽  
Depth Of Cut ◽  
Recrystallization Process ◽  
Hardness Change

Abstract The control of work hardening in laser-assisted milling process while keeping a desirable cutting efficiency is quite challenging. Surface hardness is a good indicator of the work hardening. Therefore, it is valuable to predict surface hardness in laser-assisted milling such that the effects of process parameters can be better quantified to facilitate process planning. In the current study, a general surface hardness predictive model based on theories of metal machining and microstructure evolution in laser-assisted milling process is proposed to describe the grain size variation-induced hardness change. The laser preheating temperature field is first calculated by treating the laser beam as a moving heat source. Then, the oblique milling process is transferred to equivalent orthogonal cutting process at each rotation angle to predict the grain size dependent on dynamic recrystallization process. The inverse relationship between the grain diameter and surface hardness is applied to decide grain size variation-induced hardness change. The model is validated through laser-assisted milling experiments on Ti-6Al-4V and Ti-6Al-4V ELI. The proposed predictive model is able to match the experimental measurements in all cases with an average error of 3% for Ti-6Al-4V and 3.3% for Ti-6Al-4V ELI. In addition, a sensitivity analysis is conducted on Ti-6Al-4V to study the influences of cutting speed, depth of cut, laser power, and laser-tool distance on hardness. The proposed analytical model is valuable for providing a fast, credible, and physics-based method for the prediction of surface hardness in laser-assisted milling of various materials. Through sensitivity analysis, the model is able to guide the selection of cutting and laser parameters when the control of surface hardness is the main target.

scholarly journals The Influence of Crystallographic Texture on Dynamic Recrystallization

1999 ◽  
Vol 32 (1-4) ◽  
pp. 47-63 ◽  
Author(s):  
R. Kaibyshev ◽  
B. Sokolov ◽  
A. Galiyev
Keyword(s):  
Grain Size ◽  
Dynamic Recrystallization ◽  
Crystallographic Texture ◽  
Strong Dependence ◽  
Dislocation Slip ◽  
Recrystallization Process ◽  
Compression Axis ◽  
Initial Texture ◽  
Recrystallized Grain Size ◽  
Kinetics Of

The influence of a crystallographic texture (CT) on Dynamic Recrystallization (DRX) was investigated at T= 300℃ and 2.8 x 10-3 s-1 in Mg–5.8% Zn–0.65% Zr in detail. It was shown that mechanics and kinetics of DRX are in strong dependence on location of basal planes. Initial texture effects recrystallized grain size too. Extensive recrystallization process was observed in cases when basal planes locate parallelly or at right angles to a compression axis. Almost full recrystallization structure was formed after moderate strains. If basal planes locate at 45° to the compression axis DRX occurs slowly and the formed grain size is less as compared to the other two cases. Microstructure evolution was considered in context of relationship between DRX and mechanisms of plastic deformation. It was established that the effect of initial texture on DRX is promoted by its influence on the character of dislocation slip. The reasons for the influence of the character of dislocation slip on DRX are discussed.

Compressing Deformation and Microstructure of AZ61 Magnesium Alloy

2014 ◽  
Vol 1015 ◽  
pp. 203-206
Author(s):  
Quan Li ◽  
Jin Yang ◽  
Wen Jun Liu ◽  
Su Qin Luo ◽  
Ren Ju Cheng ◽  
...  
Keyword(s):  
Grain Size ◽  
Flow Stress ◽  
Magnesium Alloy ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Deformation Temperature ◽  
Hot Compression ◽  
Compression Tests ◽  
Az61 Magnesium Alloy

Hot compression tests of AZ61 magnesium alloy were performed on gleeble1500D at strain rate ranged in 0.01~1s-1 and deformation temperature 350~400°C.The results show that the flow stress and microstructures strongly depend on the deformation temperature and the strain rate. When the temperature was reduced and the strain rate was enhanced, the area after dynamic recrystallization was enhanced, and the average dynamically recrystallied grain size reduce. But the dynamically recrystallied grain size was not well-proportioned. In this paper the 350°C×1s-1 was suggested.

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