scholarly journals Johnson Cook Material and Failure Model Parameters Estimation of AISI-1045 Medium Carbon Steel for Metal Forming Applications

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 609 ◽  
Author(s):  
Mohanraj Murugesan ◽  
Dong Jung
Keyword(s):  
Flow Stress ◽  
Metal Forming ◽  
Flow Behavior ◽  
Medium Carbon Steel ◽  
Material Behavior ◽  
Model Parameters ◽  
Stress Model ◽  
Medium Carbon ◽  
Aisi 1045 ◽  
Flow Stress Model

Consistent and reasonable characterization of the material behavior under the coupled effects of strain, strain rate and temperature on the material flow stress is remarkably crucial in order to design as well as optimize the process parameters in the metal forming industrial practice. The objective of this work was to formulate an appropriate flow stress model to characterize the flow behavior of AISI-1045 medium carbon steel over a practical range of deformation temperatures (650–950 ∘ C) and strain rates (0.05–1.0 s − 1 ). Subsequently, the Johnson-Cook flow stress model was adopted for modeling and predicting the material flow behavior at elevated temperatures. Furthermore, surrogate models were developed based on the constitutive relations, and the model constants were estimated using the experimental results. As a result, the constitutive flow stress model was formed and the constructed model was examined systematically against experimental data by both numerical and graphical validations. In addition, to predict the material damage behavior, the failure model proposed by Johnson and Cook was used, and to determine the model parameters, seven different specimens, including flat, smooth round bars and pre-notched specimens, were tested at room temperature under quasi strain rate conditions. From the results, it can be seen that the developed model over predicts the material behavior at a low temperature for all strain rates. However, overall, the developed model can produce a fairly accurate and precise estimation of flow behavior with good correlation to the experimental data under high temperature conditions. Furthermore, the damage model parameters estimated in this research can be used to model the metal forming simulations, and valuable prediction results for the work material can be achieved.

Study on High Temperature Flow Stress Model of As-cast SA508-3 Low Alloy Steel

2020 ◽  
Vol 831 ◽  
pp. 25-31
Author(s):  
Pan Fei Fan ◽  
Jian Sheng Liu ◽  
Hong Ping An ◽  
Li Li Liu
Keyword(s):  
High Temperature ◽  
Flow Stress ◽  
Strain Rate ◽  
Alloy Steel ◽  
Flow Behavior ◽  
Peak Stress ◽  
Stress Model ◽  
Low Alloy Steel ◽  
Two Stage ◽  
Flow Stress Model

In order to obtain the high temperature flow behavior of as-cast SA508-3 low alloy steel, the stress-strain curves of steel are obtained by Gleeble thermal simulation compression test at deformation temperature 800°C-1200°C and strain rate 0.001s-1-1s-1. Based on Laasraoui two-stage flow stress model, a high temperature flow stress model is established by multiple linear regression method. The results show that the peak stress characteristics are not obvious at low temperature and high strain rate, which is a typical dynamic recovery characteristic. Meanwhile, the peak stress characteristics are obvious at high temperature and low strain rate, which is a typical dynamic recrystallization characteristic. By means of the comparisons between experiments and calculations, the Laasraoui two-stage flow stress model can truly reflect flow behavior of steel at high temperature, which provides theoretical guidance for the hot deformation of the steel.

scholarly journals Flow-Stress Model of 300M Steel for Multi-Pass Compression

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 438
Author(s):  
Rongchuang Chen ◽  
Jiao Zeng ◽  
Guichuan Yao ◽  
Fei Feng
Keyword(s):  
Flow Stress ◽  
Dislocation Density ◽  
Optimization Technique ◽  
Model Parameters ◽  
Stress Model ◽  
Average Dislocation Density ◽  
300M Steel ◽  
Cumulative Strain ◽  
Softening Fraction ◽  
Flow Stress Model

In this work, multi-pass compressions were performed at various strain rates (0.01 s−1, 0.1 s−1, 1 s−1, 10 s−1), temperatures (950 °C, 1050 °C, 1150 °C), inter-pass holding time (1 s, 10 s, 30 s, 120 s, 600 s), interrupt strains (0.3, 0.4, 0.5, 0.6), and total pass numbers (1, 2, 3, 4). The intriguing finding was that the recrystallized fraction, average dislocation density, and plastic cumulative strain were partly eliminated during inter-pass holding, resulting in the early occurrence of recrystallization in subsequent compression. Therefore, a parameter (Θ) to evaluate the overall softening fraction due to recrystallization was proposed, and it was then used to iteratively rectify the average dislocation density and plastic cumulative strain in flow-stress modeling. The flow-stress model parameters of 300M steel for multi-pass compression were identified using an optimization technique based on non-derivative method integrated in MATLAB software. The average deviation of calculated and experimental flow-stress was 0.88 MPa (1.35%), showing good accuracy of the flow-stress model. The microstructure evolution of 300M steel was analyzed by the change of softening fraction during multi-pass compression, which provided a useful reference for the research of stress–microstructure relationships of high-strength steels.

A New Microstructure-Sensitive Flow Stress Model for the High-Speed Machining of Titanium Alloy Ti–6Al–4V

2016 ◽  
Vol 139 (5) ◽  
Author(s):  
X. P. Zhang ◽  
R. Shivpuri ◽  
A. K. Srivastava
Keyword(s):  
Flow Stress ◽  
Titanium Alloys ◽  
High Speed ◽  
Flow Behavior ◽  
Stress Sensitivity ◽  
Machining Process ◽  
High Speed Machining ◽  
Stress Model ◽  
Mechanical State ◽  
Flow Stress Model

The flow stress in the high-speed machining of titanium alloys depends strongly on the microstructural state of the material which is defined by the composition of the material, its starting microstructure, and the thermomechanical loads imposed during the machining process. In the past, researchers have determined the flow stress empirically as a function of mechanical state parameters, such as strain, strain rate, and temperature while ignoring the changes in the microstructural state such as phase transformations. This paper presents a microstructure-sensitive flow stress model based on the self-consistent method (SCM) that includes the effects of chemical composition, α phase and β phase, as well mechanical state imposed. This flow stress is developed to model the flow behavior of titanium alloys in machining at speed of higher than 5 m/s, characterized by extremely high strains (2–10 or higher), high strain rates (104–106 s−1 or higher), and high temperatures (600–1300 °C). The flow stress sensitivity to mechanical and material parameters is analyzed. A new SCM-based Johnson–Cook (JC) flow stress model is proposed whose constants and ranges are determined using experimental data from literature and the physical basis for SCM approach. This new flow stress is successfully implemented in the finite-element (FE) framework to simulate machining. The predicted results confirm that the new model is much more effective and reliable than the original JC model in predicting chip segmentation in the high-speed machining of titanium Ti–6Al–4V alloy.

Modification of Flow Stress Model Based on Internal Variables

2011 ◽  
Vol 117-119 ◽  
pp. 582-587 ◽  
Author(s):  
Jaroslaw Nowak ◽  
Dmytro S. Svyetlichnyy ◽  
Łukasz Łach
Keyword(s):  
Flow Stress ◽  
Grain Growth ◽  
Parameters Identification ◽  
Internal Variables ◽  
Model Parameters ◽  
Stress Model ◽  
Dislocation Theory ◽  
Classic Model ◽  
Model Based ◽  
Flow Stress Model

In the paper a flow stress model based on the dislocation theory in consideration of the recrystallization is shortly presented. The model contains two parts: a classic model of dislocation evolution and recrystallization model. The latter considers different kinds of recrystallization as the same process rooted in nucleation and grain growth. The results of the model parameters identification and the simulation are presented in this paper. Then disadvantages of the model are considered and new proposal for improvement the model are presented. Results of preliminary simulation are presented as well

scholarly journals A Flow Stress Model of 300M Steel for Isothermal Tension

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 252
Author(s):  
Rongchuang Chen ◽  
Shiyang Zhang ◽  
Xianlong Liu ◽  
Fei Feng
Keyword(s):  
Flow Stress ◽  
Constitutive Model ◽  
Tensile Deformation ◽  
Flow Behavior ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Model Parameters ◽  
Average Deviation ◽  
Cross Sectional ◽  
300M Steel

To investigate the effect of hot working parameters on the flow behavior of 300M steel under tension, hot uniaxial tensile tests were implemented under different temperatures (950 °C, 1000 °C, 1050 °C, 1100 °C, 1150 °C) and strain rates (0.01 s−1, 0.1 s−1, 1 s−1, 10 s−1). Compared with uniaxial compression, the tensile flow stress was 29.1% higher because dynamic recrystallization softening was less sufficient in the tensile stress state. The ultimate elongation of 300M steel increased with the decrease of temperature and the increase of strain rate. To eliminate the influence of sample necking on stress-strain relationship, both the stress and the strain were calibrated using the cross-sectional area of the neck zone. A constitutive model for tensile deformation was established based on the modified Arrhenius model, in which the model parameters (n, α, Q, ln(A)) were described as a function of strain. The average deviation was 6.81 MPa (6.23%), showing good accuracy of the constitutive model.

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