Study on Microstructure Evolution in GH4169 Alloy Blade during Finish Forging

2012 ◽  
Vol 217-219 ◽  
pp. 1671-1675 ◽  
Author(s):  
Guang Xia Qi ◽  
Rui Bin Mei ◽  
Na Cao
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Grain Size ◽  
Dynamic Recrystallization ◽  
Microstructure Evolution ◽  
Prediction Error ◽  
Compression Tests ◽  
Deform 3D ◽  
Gh4169 Alloy ◽  
Good Agreement

Constitutive equations and dynamic recrystallization (DRX) model of GH4169 alloy were investigated using compression tests with temperature 940(°C)-1060(°C) and strain rate 0.001(s-1)-0.1(s-1). A coupled numerical simulation between thermal-mechanical and microstructure evolution was realized through embedding the developed user subroutines into the FEM software DEFORM-3D system. The simulated results show that higher speed of upper die is useful to the DRX but much higher and lower speed of upper die go against improving the finer and uniform of grain size in the blade. Furthermore, the grains are finer and uniform in the blade body compared with those of blade rabbet and damper platform. The experimental results of microstructure under the same forging condition were studied and the average grain degrees in the blade are over 9. The calculated results of microstructure have a good agreement with the measured value from experimental data and the prediction error is less than 7.0%. Therefore, the DRX model and developed program is reliable to optimize and improve the parameters in the blade finish forging.

A Numerical Simulation of Microstructure Evolution of GH4169 Alloy Blade during Finish Forging

2011 ◽  
Vol 704-705 ◽  
pp. 113-118
Author(s):  
G. X. Qi ◽  
Rui Bin Mei ◽  
F Wang ◽  
L Bao
Keyword(s):  
Numerical Simulation ◽  
Grain Size ◽  
Microstructure Evolution ◽  
Equivalent Strain ◽  
Average Grain Size ◽  
Back Edge ◽  
3D Software ◽  
Deform 3D ◽  
Gh4169 Alloy ◽  
Good Agreement

In order to predict the microstructure evolution and grain size of GH4169 alloy blade in finish forging process and optimize the parameters, a coupled simulation between thermal mechanical and microstructure evolution was realized through embedding the developed user subroutines into the DEFORM-3D software. The temperature, equivalent strain, dynamic recrystallization fraction, average grain size and grain size distribution were predicted and discussed. The experimental results of microstructure under the same forging condition were investigated. The average grain degree in the blade rabbet and body are 8 and 10 respectively. The calculated results of microstructure have a good agreement with the measured value from experimental data and the prediction error of average grain size is less than 6.7%. The developed program is reliable and the accuracy is satisfying. The distribution of grain size along the blade body is decreased from the middle to the leading and back edge. The shape and microstructure after finish forging under the condition of technology parameters meet the user’s requirement. Keywords: Blade, GH4169 alloy, Numerical simulation, Microstructure, Forging

Numerical Simulation for Microstructure Evolution in In718 Alloy During Cylindrical Cup Backward Extrusion

2013 ◽  
Vol 650 ◽  
pp. 92-97 ◽  
Author(s):  
X. Hu ◽  
R. B. Mei ◽  
F. Zhu ◽  
Y. Fan ◽  
Y. B. Liang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Grain Size ◽  
Dynamic Recrystallization ◽  
Microstructure Evolution ◽  
Cylinder Wall ◽  
Backward Extrusion ◽  
Average Grain Size ◽  
Higher Temperature ◽  
Cylindrical Cup ◽  
Deform 3D

A coupled numerical simulation between thermal-mechanical and microstructure evolution was realized through embedding the developed user subroutines into the FEM software DEFORM-3D system. Then the dynamic recrystallization fraction and average grain size of In718 alloy in cylindrical cup backward extrusion with different parameters was solved and analyzed. The complete dynamic recrystallization occurs in the middle of cylinder wall and the grain size is the finest. However, the grain size of top of cylinder wall changes less because of the less plastic deformation. Furthermore, higher speed of punch is useful to the DRX but it is not enough time to occur dynamic recrystallization completely with much higher speed of punch. In spite of more recrystallization occurring in the bottom, the grains grow in the cylinder wall so that much higher temperature goes against improving finer and uniform of grain size. Therefore, it is better for obtaining finer and uniform grain size with 1000(°C)-1050(°C) and 5(mm/s) in In718 alloy cylindrical cup backward extrusion according to the research.

Research on Temperature Change and Microstructure Evolution of Bore in Steel Target Penetrated by Copper Jets

2010 ◽  
Vol 667-669 ◽  
pp. 641-646
Author(s):  
Hao Chen ◽  
Gang Tao
Keyword(s):  
Numerical Simulation ◽  
Grain Size ◽  
Dynamic Recrystallization ◽  
Temperature Change ◽  
Microstructure Evolution ◽  
Channel Wall ◽  
Cooling Time ◽  
Steel Target

Copper fragments are found to adhere on penetration channel wall after copper jets penetrate steel target, and the research on it is helpful to know microstructure evolution of jets in the process of penetration and cooling time. This paper is based on the observation of bore in steel target penetrated by copper jets, and uses numerical simulation to study the process of copper jets penetration, then the change of temperature and grain size of jets adhered on penetration channel wall can be gotten, and the results agree with the observation of penetration channel wall taken by SEM. From the observations of copper and steel, we can get the conclusion that copper jets are not melted but have dynamic recrystallization in the process of penetration, then copper grain size increases obviously in cooling time, and twins are formed at the same time.

Microstructure Evolution in Undercooled Ni-Si Melt

2013 ◽  
Vol 749 ◽  
pp. 349-355
Author(s):  
Kai Fan ◽  
Feng Liu ◽  
Bao Quan Fu ◽  
Wen Zhong Luo ◽  
Yao He Zhou
Keyword(s):  
Experimental Data ◽  
Grain Size ◽  
Grain Refinement ◽  
Microstructure Evolution ◽  
Solid Solubility ◽  
Molten Glass ◽  
Dendrite Fragmentation ◽  
Equilibrium Solidification ◽  
Good Agreement ◽  
Non Equilibrium

Upon non-equilibrium solidification, the intrinsic parameters, such as moving velocity, temperature, solute partition coefficient, and liquid and solid concentrations at the interface, deviate from their equilibrium characteristics, and the morphology of the as-solidified structure and the grain size are influenced by the non-equilibrium liqulid/solid transformation, which further influences the subquent solidstate transformation. Adopting molten glass purification technology combined with cycle superheating method, the microstructure evolution of Ni-11at.%Si alloy in different undercooling was investigated. It was found that, with the increase of the initial undercooling, grain refinement occurred in microstructures of undercooled Ni-11at.%Si alloy. Meanwhile, the NL model was used to discuss the two different dendrite morphologies. According to Karmas model for dendrite fragmentation, the grain refinement of undercooled Ni-11at.%Si alloy was in good agreement with the experimental data, and the grain size was reduced with the increasing ΔT. The energy-dispersive spectroscopy (EDS) measurement was applied to analyze the solid solubility of Si atom in α-Ni matrix. It was found that the solid solubility of Si atom in α-Ni matrix increased with undercooling. At the undercooling of T>220K , a complete solute trapping occurred.

New Model for Characterization of Dynamic Recrystallization and Prediction of Grain Size Applied to Two Wrought Magnesium Alloys

2008 ◽  
Vol 604-605 ◽  
pp. 87-96 ◽  
Author(s):  
Ignacio Rieiro ◽  
Jesus Castellanos ◽  
Manuel Carsí ◽  
Julio Muñoz ◽  
Oscar A. Ruano
Keyword(s):  
Experimental Data ◽  
Grain Size ◽  
Dynamic Recrystallization ◽  
Magnesium Alloys ◽  
Linear Optimization ◽  
Optimization Methods ◽  
Size Refinement ◽  
Strain Dependent ◽  
Good Agreement

A model for describing the plastic flow has been developed. The model is based on a strain dependent Garofalo equation and predicts the variation with strain of grain size refinement by dynamic recrystallization using non-linear optimization methods. The predictions have been applied to two wrought magnesium alloys, AZ31 and AZ61 and are in good agreement with experimental data.

Study on Dynamic Recrystallization Behavior in Deformed Austenite of 52100 Steel by Using JMAK-Model

2013 ◽  
Vol 275-277 ◽  
pp. 1833-1837
Author(s):  
Ke Lu Wang ◽  
Shi Qiang Lu ◽  
Xin Li ◽  
Xian Juan Dong
Keyword(s):  
Grain Size ◽  
Dynamic Recrystallization ◽  
Hot Deformation ◽  
Volume Fraction ◽  
True Strain ◽  
Strain And Strain Rate ◽  
Average Grain Size ◽  
Dynamic Recrystallization Behavior ◽  
Simulation And Experiment ◽  
Good Agreement

A Johnson-Mehl-Avrami-Kolmogorov (JMAK)-model was established for dynamic recrystallization in hot deformation process of 52100 steel. The effects of hot deformation temperature, true strain and strain rate on the microstructural evolution of the steel were physically studied by using Gleeble-1500 thermo-mechanical simulator and the experimental results were used for validation of the JMAK-model. Through simulation and experiment, it is found that the predicted results of DRX volume fraction, DRX grain size and average grain size are in good agreement with the experimental ones.

scholarly journals An Investigation into the Dynamic Recrystallization (DRX) Behavior and Processing Map of 33Cr23Ni8Mn3N Based on an Artificial Neural Network (ANN)

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1282 ◽  
Author(s):  
Zhongman Cai ◽  
Hongchao Ji ◽  
Weichi Pei ◽  
Xuefeng Tang ◽  
Long Xin ◽  
...  
Keyword(s):  
Neural Network ◽  
Experimental Data ◽  
Artificial Neural Network ◽  
Dynamic Recrystallization ◽  
Microstructure Evolution ◽  
Processing Map ◽  
Resistant Steel ◽  
Ann Model ◽  
Heat Resistant Steel ◽  
Artificial Neural Network Ann

Based on an 33Cr23Ni8Mn3N thermal simulation experiment, the application of an artificial neural network (ANN) in thermomechanical processing was studied. Based on the experimental data, a microstructure evolution model and constitutive equation of 33Cr23Ni8Mn3N heat-resistant steel were established. Stress, dynamic recrystallization (DRX) fraction, and DRX grain size were predicted. These models were evaluated by a variety of statistical indicators to determine that these models would work well if applied in predicting microstructure evolution and that they have high precision. Then, based on the weight of the ANN model, the sensitivity of the input parameters was analyzed to achieve an optimized ANN model. Based on the most widely used sensitivity analysis (SA) method (the Garson method), the input parameters were analyzed. The results show that the most important factor for the microstructure of 33Cr23Ni8Mn3N is the strain rate ( ε ˙ ). For the control of the microstructure, the control of the ε ˙ is preferred. ANN was applied to the development of processing map. The feasibility of the ANN processing map on austenitic heat-resistant steel was verified by experiments. The results show that the ANN processing map is basically consistent with processing map based on experimental data. The trained ANN model was implanted into finite element simulation software and tested. The test results show that the ANN model can accurately expand the data volume to achieve high precision simulation results.

Numerical Simulation and Experimental Verification of Microstructure Evolution during the Seamless Tube Extrusion of Semi-Continuous Casting AZ31 Magnesium Alloy

2017 ◽  
Vol 898 ◽  
pp. 79-85
Author(s):  
Tao Lin ◽  
Ji Xue Zhou ◽  
Bai Chang Ma ◽  
Yun Teng Liu ◽  
Di Zhang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Magnesium Alloy ◽  
Continuous Casting ◽  
Dynamic Recrystallization ◽  
Volume Fraction ◽  
Seamless Tube ◽  
Compression Tests ◽  
Extrusion Speed ◽  
Tube Extrusion ◽  
Az31 Mg Alloy

Based on the stress-strain curves at the temperature of 300-450 °C with strain rate of 0.01-1 s−1 by hot compression tests, the empirical dynamic recrystallization models for the semi-continuous AZ31magnesium alloy were developed. The dynamic recrystallization evolution during the seamless tube extrusion of the AZ31 Mg alloy was simulated by numerical method with the derived models and validated by experiment measurements. The results show that at certain extrusion speed the influence of the extruding temperature on the dynamic recrystallization fraction was significant. With the increase of the extruding temperature the volume fraction of dynamic recrystallization increase obviously. The predicted dynamic recrystallization fraction was in an excellent agreement with the experimental results.

scholarly journals Study of Static Recrystallization Kinetics and the Evolution of Austenite Grain Size by Dynamic Recrystallization Refinement of an Eutectoid Steel

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1289
Author(s):  
Cesar Facusseh ◽  
Armando Salinas ◽  
Alfredo Flores ◽  
Gerardo Altamirano
Keyword(s):  
Grain Size ◽  
Dynamic Recrystallization ◽  
Static Recrystallization ◽  
Controlled Rolling ◽  
Strain Rates ◽  
Peak Strain ◽  
Compression Tests ◽  
Eutectoid Steel ◽  
Austenite Grain Size ◽  
Austenite Grain

Interrupted and continuous hot compression tests were performed for eutectoid steel over the temperature range of 850 to 1050 °C and while using strain rates of 0.001, 0.01, 0.1, and 1 s−1. The interrupted tests were carried out to characterize the kinetics of static recrystallization(SRX) and determinate the interpass time conditions that are required for initiation and propagation of dynamic recrystallization (DRX), while considering that the material does not contain microalloying elements additions for the recrystallization delay. Continuous testing was used to investigate the evolution of the austenite grain size that results from DRX. The results indicate that carbon content accelerates the SRX rate. This effect was observed when the retardation of recrystallization due to a decrease in deformation temperature from 1050 to 850 °C was only about one order of magnitude. The expected decelerate effect on the SRX rate when the initial grain size increases from 86 to 387 µm was not significant for this material. Although the strain parameter has a strong influence on SRX rate, in contrast to a lesser degree of strain rate, both of the effects are nearly independent of the chemical composition. The calculated maximum interpass times that are compatible with DRCR (Dynamic Recrystallization Controlled Rolling), for relatively low strain rates, suggest that the onset and maintaining of the DRX is possible. However, while using the empirical equations that were developed in the present work to estimate the maximum times for high strain rates, such as those observed in the wire and rod mills, indicate that the DRX start is feasible, but maintaining this mechanism for 5% softening in each pass after peak strain is not possible.

scholarly journals Numerical Simulation of Rotor in Hover and Forward Flight

2018 ◽  
Vol 179 ◽  
pp. 03011
Author(s):  
Qinghe Zhao
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Flow Field ◽  
Moving Grid ◽  
Steady State Flow ◽  
Forward Flight ◽  
Numerical Simulation Result ◽  
Structured Grid ◽  
Pressure Distributions ◽  
Good Agreement

The flow around rotor is numerical simulated in hover and forward flight based on multi-structured grid. In hover the flow field can be transformed into a steady-state flow field in the rotating coordinate system. The experimental data of Caradonna and Tung rotor is used to verify the numerical simulation result. The numerical results compare well with the experimental data for both non-lifting and lifting cases. Non-lifting forward flight is simulated and the prediction capabilities have been validated through the ONERA two-blade rotor. The pressure distributions of different positions under different azimuth angles are compared, which is in good agreement with the experimental data. There is unsteady shock wave when forward flight. Dual-time method is used to obtain unsteady flow field with rigid moving grid in the inertial system.

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