Flow and Densification Behaviors of Sintered P/F-10C50 Steel under Hot Compression

2016 ◽  
Vol 849 ◽  
pp. 811-818
Author(s):  
Biao Guo ◽  
Chang Chun Ge ◽  
Yi Xu ◽  
Qiu Yan Lu ◽  
Sui Cai Zhang
Keyword(s):  
Constitutive Equation ◽  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Temperature ◽  
Hot Compression ◽  
Compression Tests ◽  
Sintered Steel ◽  
Absolute Relative Error ◽  
Average Absolute Relative Error ◽  
Deformation Behaviors

The hot deformation and densification behaviors of sintered P/F-10C50 steel were investigated by hot compression tests on Gleeble-1500 thermal mechanical simulator at the temperature ranging from 900 °C to 1000 °C and the strain rate ranging from 0.1 s-1 to 10 s-1. The flow and densification characteristics of the tested specimens at different deformation temperatures and strain rates were studied. The flow stress of the sintered steel persistently increases until the end of the test as the result of matrix and geometric work hardening. The higher deformation temperature and strain rate are conductive to the healing of the pores and promote the densification of the sintered steel, while the higher deformation temperature and lower strain rate impede the densification. The constitutive equation of the sintered steel is established by the means of stepwise regression. The flow stresses predicted by the established constitutive equation are in good agreement with the experimental values, and the correlation coefficient (R) and the average absolute relative error (AARE) are 0.9931 and 3.52%, respectively. These results demonstrate the hot deformation behaviors of the sintered P/F-10C50 steel are excellently predicted by the established constitutive equation.

Hot Deformation Behaviors of SiCp/Al Composites

2014 ◽  
Vol 1058 ◽  
pp. 165-169 ◽  
Author(s):  
Shi Ming Hao ◽  
Jing Pei Xie
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Hot Deformation ◽  
True Strain ◽  
Constant Strain Rate ◽  
Hot Compression ◽  
Compression Tests ◽  
Sensitive Material ◽  
2024 Aluminum Alloy ◽  
Deformation Behaviors

The hot deformation behaviors of 30%SiCp/2024 aluminum alloy composites was studied by hot compression tests using Gleeble-1500 thermomechanical simulator at temperatures ranging from 350-500°C under strain rates of 0.01-10 s-1. The true stress-true strain curves were obtained in the tests. Constitutive equation and processing map were established. The results show that the flow stress decreases with the increase of deformation temperature at a constant strain rate, and increases with the increase of strain rate at constant temperature, indicating that composite is a positive strain rate sensitive material. The flow stress behavior of composite during hot compression deformation can be represented by a Zener-Hollomon parameter in the hyperbolic sine form. Its activation energy for hot deformation Q is 183.251 kJ/mol. The optimum hot working conditions for this material are suggested.

Prediction of High Temperature Flow Stress for AISI 4120 Steel during Hot Compression

2012 ◽  
Vol 233 ◽  
pp. 339-342 ◽  
Author(s):  
Ming Ping Zou ◽  
Wu Jiao Xu ◽  
Peng Cheng Wang
Keyword(s):  
High Temperature ◽  
Flow Stress ◽  
Constitutive Equation ◽  
Constitutive Equations ◽  
Good Prediction ◽  
Compression Tests ◽  
Absolute Relative Error ◽  
Constitutive Analysis ◽  
Average Absolute Relative Error ◽  
Deformation Behaviors

To investigate the hot deformation behaviors of AISI 4120 steel, isothermal compression tests were conducted using Gleeble-1500 thermal-mechanical simulator in the temperature range of 1073-1373K with the strain rate of 0.01-10s-1. The hyperbolic sine law in Arrhenius type is used in the constitutive modeling for AISI 4120. The influence of strain is incorporated in constitutive analysis by considering the effect of strain on material constants α, n, Q and ln A. The flow stress values predicted by the developed constitutive equations show a good agreement with experimental results, which reveals that the developed constitutive equations could give an accurate and precise prediction for the high temperature flow behaviors of AISI 4120 steel. The predictability of developed constitutive equation was further quantified in terms of correlation coefficient (R) and average absolute relative error (AARE). The R and AARE were found to be 0.9847 and 8.0372% respectively, which reflects the good prediction capabilities of the developed constitutive equation.

Hot Deformation Behaviors of SiCp/2024 Aluminum Composites

2013 ◽  
Vol 833 ◽  
pp. 271-275
Author(s):  
Shi Ming Hao ◽  
Jing Pei Xie
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Hot Deformation ◽  
True Strain ◽  
Constant Strain Rate ◽  
Hot Compression ◽  
Compression Tests ◽  
Sensitive Material ◽  
2024 Aluminum Alloy ◽  
Deformation Behaviors

The hot deformation behaviors of 30%SiCp/2024 aluminum alloy composites was studied by hot compression tests using Gleeble-1500 thermomechanical simulator at temperatures ranging from 350-500 °C under strain rates of 0.01-10 s-1. The true stress-true strain curves were obtained in the tests. Constitutive equation and processing map were established. The results show that the flow stress decreases with the increase of deformation temperature at a constant strain rate, and increases with the increase of strain rate at constant temperature, indicating that composite is a positive strain rate sensitive material. The flow stress behavior of composite during hot compression deformation can be represented by a Zener-Hollomon parameter in the hyperbolic sine form. Its activation energy for hot deformation Q is 153.251 kJ/mol. The optimum hot working conditions for this material are suggested.

scholarly journals A Strain-Compensated Constitutive Model for Describing the Hot Compressive Deformation Behaviors of an Aged Inconel 718 Superalloy

2019 ◽  
Vol 38 (2019) ◽  
pp. 436-443 ◽  
Author(s):  
Ying Zhou ◽  
Xiao-Min Chen ◽  
Shengfeng Qin
Keyword(s):  
Constitutive Equation ◽  
Strain Rate ◽  
Hot Deformation ◽  
Inconel 718 ◽  
Deformation Temperature ◽  
True Stress ◽  
Compressive Deformation ◽  
Deformation Behaviors ◽  
Inconel 718 Superalloy ◽  
True Stresses

AbstractThe hot deformation behaviors of an aged Inconel 718 superalloy are investigated by isothermal compression experiments at four strain rates and five deformation temperatures on a Gleeble-3500 thermo-mechanical simulator. The experimental results show that the true stresses are obviously affected by strain rate and deformation temperature. The true stress increases rapidly at the beginning of hot compressive deformation, which ascribes to the intense work hardening. The true stresses at high deformation temperatures are lower than those at lower deformation temperatures. The dynamic softening induced by DRX is weak at a relatively low deformation temperature. A strain-compensated Arrhenius-type constitutive equation linked with true stress, strain rate and deformation temperature is developed for the studied superalloy. The material constants (\alpha , n, Q and A) in the developed model are expressed as the functions of true strain. The flow stresses calculated by the developed constitutive equation are nicely consistent with the experimental ones, which confirms that the developed constitutive equation can accurately describe the hot deformation behaviors of the studied superalloy.

Constitutive Modeling for Flow Behavior of As-Cast 1026 Carbon Steel Under Hot Compression Experiments

2015 ◽  
Author(s):  
Li Ju ◽  
Yongtang Li ◽  
Jianhua Fu ◽  
Bufang Lei ◽  
Huiping Qi
Keyword(s):  
Flow Stress ◽  
Carbon Steel ◽  
Constitutive Equation ◽  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Temperature ◽  
Flow Behavior ◽  
Hot Compression ◽  
Stress Index ◽  
Heating Process

Nowadays, modern casting theories and technologies have got marked progress in reducing steel casting’s defects, such as shrinkages, cracks, porosities, and segregations, which make it possible to manufacture industrial parts with casting instead of forging billet. Compared with the traditional technology, the new method will have many obvious advantages in reducing heating times and discharge, saving materials and energy, and improving productivity. In order to produce parts with sound mechanical properties by employing the new technology, it is important to probe the flow behavior of as-cast carbon steel under hot deformation for premium controlling processing parameters, reasonable planning procedures and a reliable constitutive equation for precise simulation. In this paper, high temperature flow behavior of as-cast 1026 carbon steel is investigated by conducting hot compression experiments on Gleeble-3500 simulator in the temperature range from 1 173 K to 1 473 K at an interval of 100 K and the stain rate range from 0.1 s−1 to 2.0 s−1. The relationships of deformation parameters (temperature, strain rate) with material’s flow behavior are found. The deformation activation energy and the stress index are worked out and the mathematical model of the flow stress under hot deformation is established by means of the liner regression analysis of true stress-strain data. Meanwhile, the effect of initial grain sizes on flow behavior of as-cast 1026 steel is also studied by compressing samples cooled to 1 173 K from 1 273 K, 1 373 K and 1 473 K respectively. The experimental results reveal that strain hardening and flow softening mainly characterize the flow behavior. It is also found that with the increase of deformation, the flow stress first increases rapidly, then reaches the peak slowly, after that it begins to decrease and finally comes to a steady value. At the temperature of 1 173 K, material’s softening is not apparent even if the strain rate is increased, while at the strain rate of 2 s−1, it is also not apparent even when the deformation temperature is raised to 1 473 K, so the final forging temperature is supposed to be about 1 173 K and the maximum stain rates should be below 2 s−1. In addition, at the same deformation temperature and strain rate, the more refined initial grain, the easier material dynamically recrystallizes and the lower the steady stress is. Therefore, the heating process of material is expected to be tightly controlled. The maximum error of flow stress between the model predictions and actual results is only 5.90%. The good agreement signifies the applicability of this method as a general constitutive equation in hot deformation studies.

Constitutive Equation and Dynamic Softening Behavior of 7A55 Aluminum Alloy during Compression at Elevated Temperatures

2017 ◽  
Vol 898 ◽  
pp. 291-299
Author(s):  
Di Feng ◽  
Xin Ming Zhang ◽  
Sheng Dan Liu
Keyword(s):  
Aluminum Alloy ◽  
Constitutive Equation ◽  
Strain Rate ◽  
Hot Deformation ◽  
Elevated Temperatures ◽  
Boundary Migration ◽  
Compression Tests ◽  
Softening Mechanism ◽  
Softening Behavior ◽  
Deformation Behaviors

The hot deformation behaviors of 7A55 aluminum alloy were investigated by compression tests at temperatures ranging from 270°C to 450°C and strain rate ranging from 0.1s−1 to 25s−1. Tha rResults show that the flow stress increased with increasing strain rate and decreasing temperature. A two-stage constitutive equation was established and the hot deformation activation energy was 140 kJ/mol. EBSD observations show that the fine and equiaxed grains with the misorientation angle above 15° nucleated at the initial grain boundaries under high temperature and low strain rate conditions. It is concluded that the softening mechanism of 7A55 aluminum alloy is dynamic recovery (DRV), together with a partial dynamic recrystallization (DRX). The nucleation mechanism of DRX could be explained by the strain induced grain boundary migration (SIBM). The DRX softening model was established based on the dislocation density theory finally.

Hot Compression Deformation Behavior of Spray-Formed AlSn20Cu Alloy

2021 ◽  
Vol 1035 ◽  
pp. 189-197
Author(s):  
Bao Ying Li ◽  
Bao Hong Zhu
Keyword(s):  
Constitutive Equation ◽  
Strain Rate ◽  
Deformation Behavior ◽  
Deformation Temperature ◽  
Phase Distribution ◽  
True Stress ◽  
Hot Compression ◽  
Test Machine ◽  
Hot Compression Deformation ◽  
Compression Deformation

The hot deformation behavior of spray-formed AlSn20Cu alloy during hot compression deformation was studied, and the constitutive equation of AlSn20Cu alloy was established. The samples of spray-formed AlSn20Cu alloy were compressed on Gleeble-3500 thermal simulation test machine. The error of the true stress caused by adiabatic heating effect in the experiment was corrected. The constitutive equation of spray-formed AlSn20Cu alloy could be represented by Zener-Hollomon parameter in a hyperbolic sine function. The results showed that the deformation temperatures and strain rates had a notable effect on the true stress of the alloy. At the identical deformation temperature, the true stress increased with the increase of strain rate. When the strain rate was constant, the stress decreased with the increase of deformation temperature. After hot compression deformation, the tin phase was elongated along the direction perpendicular to the compression axis with short strips and blocks. With the increase of deformation temperature and the decrease of strain rate, Sn phase distribution became more homogeneous.

Effect of Hot Deformation Parameters on Flow Behavior and Microstructure of Ti-6Al-4V-0.2O Alloy

2017 ◽  
Vol 898 ◽  
pp. 137-143
Author(s):  
Lin Xiang ◽  
Bin Tang ◽  
Hong Chao Kou ◽  
Jie Shao ◽  
Jin Shan Li
Keyword(s):  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Temperature ◽  
Dynamic Recovery ◽  
Volume Fraction ◽  
Flow Behavior ◽  
Strain Rates ◽  
Compression Tests ◽  
Height Reduction ◽  
Deformation Parameters

Isothermal compression tests were conducted to investigate the effect of hot deformation parameters on flow behavior and microstructure of Ti-6Al-4V-0.2O alloy. The experimental results show that the strain rate and height reduction have little effect on the volume fraction of primary α at a deformation temperature of 860 ̊C. At a deformation temperature of 940 ̊C, the volume fraction of primary α at a high strain rate (10s-1) is about 10% less than that at low strain rates (0.01s-1~1s-1). It may be one of the reasons for the significantly discontinuous yielding phenomenon. Another reason is that the dislocation density decreased suddenly due to the dynamic recovery. With the increasing strain rate and the decreasing deformation temperature, the volume fraction of irregular secondary α increases and lamellar secondary α decreases. And with height reduction increasing, the irregular secondary α increases firstly and then tends to be steady because of dynamic recovery and recrystallization.

A Modified Double Multiple Nonlinear Regression Constitutive Equation for Modeling and Prediction of High Temperature Flow Behavior of BFe10-1-2 Alloy

2018 ◽  
Vol 37 (1) ◽  
pp. 75-87
Author(s):  
Jun Cai ◽  
Kuaishe Wang ◽  
Jiamin Shi ◽  
Wen Wang ◽  
Yingying Liu
Keyword(s):  
Flow Stress ◽  
Constitutive Equation ◽  
Strain Rate ◽  
Nonlinear Regression ◽  
Flow Behavior ◽  
Strain Rate Range ◽  
Compression Tests ◽  
Constitutive Analysis ◽  
Average Absolute Relative Error ◽  
Wide Range

AbstractConstitutive analysis for hot working of BFe10-1-2 alloy was carried out by using experimental stress–strain data from isothermal hot compression tests, in a wide range of temperature of 1,023~1,273 K, and strain rate range of 0.001~10 s–1. A constitutive equation based on modified double multiple nonlinear regression was proposed considering the independent effects of strain, strain rate, temperature and their interrelation. The predicted flow stress data calculated from the developed equation was compared with the experimental data. Correlation coefficient (R), average absolute relative error (AARE) and relative errors were introduced to verify the validity of the developed constitutive equation. Subsequently, a comparative study was made on the capability of strain-compensated Arrhenius-type constitutive model. The results showed that the developed constitutive equation based on modified double multiple nonlinear regression could predict flow stress of BFe10-1-2 alloy with good correlation and generalization.

scholarly journals Constitutive Equation and Hot Processing Map of a Nitrogen-Bearing Martensitic Stainless Steel

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1502
Author(s):  
Xiao Li ◽  
Lifeng Hou ◽  
Yinghui Wei ◽  
Zhengyan Wei
Keyword(s):  
Stainless Steel ◽  
Constitutive Equation ◽  
Strain Rate ◽  
Hot Deformation ◽  
Processing Map ◽  
Martensitic Stainless Steel ◽  
True Strain ◽  
True Stress ◽  
Hot Working ◽  
Compression Tests

The hot deformation behavior of a nitrogen-bearing martensitic stainless steel was researched by the isothermal compression test in the temperature range of 950–1150 °C and strain rate range of 0.01–10 s−1 with a Gleeble-3800 thermal-mechanical simulating tester. A strain compensated sine-hyperbolic Arrhenius-type constitutive equation was developed to describe the relationship between true stress and deformation parameters such as temperature, strain rate and true strain. The hot deformation activation energy is calculated to be from 407 to 487 KJ mol−1. It is validated by the standard statistical parameters that the established constitutive equation can accurately predict the true stress. The processing maps at different true strains were constructed based on the dynamic material model (DMM) and the true stress data obtained from the hot compression tests. Two unstable regions which should be avoided during hot working were observed from the processing map. In addition, the optimum hot working parameters are located in the domain of 1000–1150 °C/0.1–1 s−1 with the peak power dissipation efficiency of 39.9%, in which complete dynamic recrystallization (DRX) occurs.

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