Effect of Temperature and Strain Rate of The Hot Deformation of V Microalloyed Steel on Flow Stress

Author(s):  
Md Israr Equbal ◽  
Azhar Equbal ◽  
Md. Asif Equbal ◽  
R. K. Ohdar

Medium carbon micro-alloyed forging steels are employed in various automotive components. The impetus for the use of micro alloyed (MA) steels is cost reduction due to elimination of post-forging heat treatment. Compared to conventional quenched and tempered steels micro-alloyed steels can achieve similar or more superior properties simply by properly controlling the process parameters. Forging temperature, strain, strain rate and cooling rate are some of the important process parameters that influence the flow stress and final forging product quality. In the present study, hot compression test on a micro-alloyed steel grade 38MnSiVS5 were conducted on thermo-mechanical simulator (Gleeble-3500) to study the effect of temperature and strain rate on flow stress. The results indicate that the flow stress of 38MnSiVS5 steel is greatly affected by both deformation temperature and strain rate. Obtained true stress-true strain curves showed that the flow stress of the alloy increased by increasing the strain rate and decreasing the temperature, which can be represented in terms of an exponent type Zener-Hollomon equation. Finally, the constitutive equations for the flow behavior of 38MnSiVS5 microalloyed steel were determined.

2014 ◽  
Vol 651-653 ◽  
pp. 38-41
Author(s):  
Ling Zhan Zhou ◽  
Li Ming Yang ◽  
Yin Jiang Peng ◽  
Xiu Rong Zhu

Fe-Cr-Ni preform reinforcing aluminum composite was produced by squeeze casting. And then, T6 heat treatment was conducted to enhance the composite’s performance. After which, isothermal compression tests in temperature range of 298 - 473 K at an strain rate range from 0.001 to 10 s-1 were carried out on Gleeble 3500 thermo-mechanical simulation machine. It is found that, for a specific strain rate, the flow stress decreases markedly with temperature increases. And for a fixed temperature, the flow stress generally increases as the strain rate increases. Based on the experimental true stress-true strain data, the Arrhenius type model was established.


2013 ◽  
Vol 592-593 ◽  
pp. 724-727
Author(s):  
Andrzej Nowotnik ◽  
Paweł Rokicki ◽  
Paweł Pędrak ◽  
Slawomir Kotowski ◽  
Jan Sieniawski ◽  
...  

Variations of a true stress vs. true strain illustrate behaviour of materials during plastic deformation. Stress-strain relationship is generally evaluated by a torsion, compression and tensile tests. Results of these tests provide crucial information pertaining to the stress values which are necessary to run deformation process at specified temperature and cooling rate. Uniaxial compression tests at temperatures below the γ solvus were conducted on nickel based superalloy CMSX-4, to study the effect of temperature and strain rate on its flow stress. On the basis of received flow stress values activation energy of a high-temperature deformation process was estimated. Mathematical dependences (σpl -T i σpl - ἐ) and compression data were used to determine material constants. These constants allow to derive a formula that describes the relationship between strain rate, deformation temperature and true stress.


2014 ◽  
Vol 633-634 ◽  
pp. 431-435 ◽  
Author(s):  
Ling Zhan Zhou ◽  
Li Ming Yang ◽  
Yin Jiang Peng ◽  
Xiu Rong Zhu

In this paper, squeeze casting process was adopted to produce the Fe-Cr-Ni preform reinforced Al-Si-Cu-Ni-Mg aluminum composite. And then, T6 heat treatment was conducted to enhance the composite’s performance. After which, isothermal compression tests in temperature range of 473-773 K at an interval of 150 K and strain rate range from 0.001 to 10 s-1 were carried out on Gleeble 3500 thermo-mechanical simulation machine. It is found that, for a specific strain rate, the flow stress decreases markedly with temperature increases. And for a fixed temperature, the flow stress generally increases as the strain rate increases. Based on the experimental true stress-true strain data, the Arrhenius type model was established.


2013 ◽  
Vol 747-748 ◽  
pp. 703-708 ◽  
Author(s):  
Tao Wang ◽  
Shu Hong Fu ◽  
Zhao Li ◽  
Yong Zhang ◽  
Yu Xin Zhao ◽  
...  

Hot compressive deformation of Udimet720Li alloy was carried out on Gleeble-3500 thermal mechanical simulator. The flow stress behavior of Udimet720Li alloy during hot compression was studied in the temperature range of 1100-1160 and at a strain rate of 0.001-1s -1. The results showed that the flow stress was controlled by both strain rate and deforming temperature. The flow stress decreased with the increase of deforming temperature, while increased with the increase of strain rate. The change of flow stress with deformation thermal parameters was revealed from true stress-true strain curves, and constitutive relationship of Udimet720Li alloy was obtained on the base of Arrhenius equations and the deformation activation energy was calculated.


2018 ◽  
Vol 207 ◽  
pp. 03016
Author(s):  
JinLong Chen ◽  
Hengcheng Liao ◽  
Heting Xu

Flow behavior of Al-2.0wt.%Cu-1.0wt.%Mn aluminum alloy was investigated by hot compressive test using a Gleebe-3800 thermal simulator. The test parameters about temperature and strain rate range from 573K to 773 K and from 0.01s-1 to 5s-1, respectively, and the true strain is up to 0.6. It can be seen that the peak flow stress increases with increasing the strain rate and decreases by deformation temperature. And the deformation activation energy of Al-2.0wt.%Cu-1.0wt.%Mn alloy is 183.02KJ/mol. A constitutive equation has been constructed to predict the hot deformation behavior, and correlate the peak flow stress predicted with strain rate and deformation temperature.


Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 782 ◽  
Author(s):  
Qiang Liang ◽  
Xin Liu ◽  
Ping Li ◽  
Xianming Zhang

The flow behavior of a new kind of high-strength nickel brass used as automobile synchronizer rings was investigated by hot compression tests with a Gleeble-3500 isothermal simulator at strain rates ranging from 0.01 to 10 s−1 and a wide deformation temperature range of 873–1073K at intervals of 50 K. The experimental results show that flow stress increases with increasing strain rate and decreasing deformation temperature, and discontinuous yielding appeared in the flow stress curves at higher strain rates. A modified Arrhenius constitutive model considering the compensation of strain was established to describe the flow behavior of this alloy. A processing map was also constructed with strain of 0.3, 0.6, and 0.9 based on the obtained experimental flow stress–strain data. In addition, the optical microstructure evolution and its connection with the processing map of compressed specimens are discussed. The predominant deformation mechanism of Cu-Ni-Al brass is dynamic recovery when the deformation temperature is lower than 973 K and dynamic recrystallization when the deformation temperature is higher than 973 K according to optical observation. The processing map provides the optimal hot working temperature and strain rate, which is beneficial in choosing technical parameters for this high-strength alloy.


Author(s):  
Shibo Wen ◽  
Chaoyu Han ◽  
Bao Zhang ◽  
Yongfeng Liang ◽  
Feng Ye ◽  
...  

The flow behavior of Fe-6.5wt.%Si alloys during hot compression was investigated at temperatures 650–950 °C and strain rates 0.01–10 s-1. The results showed that the flow stress depended distinctly on the deformation temperatures and strain rates. The flow stress and work hardening rate increased with the decrease of temperature and the increase of strain rate. The activation energy under all the deformation conditions was calculated to be 410 kJ/mol. The constitutive equation with hyperbolic sine function and Zener–Hollomon parameter was developed. The peak stress, critical stress, and steady-state stress could be represented as σ=A+Bln(Z/A). Dynamic recrystallization occurred under the deformation conditions where the values of Z were lower than 1020. Processing maps were established to optimize the processing parameters. The power dissipation efficiency decreased in the high temperature and low strain rate region, increased in the high temperature and high strain rate region, and remained unchanged in other regions with the increase of true strain. Furthermore, the unstable area expanded. The true strain of 0.7 was the optimum reduction according to the processing map. Based on the analysis of surface quality, microstructures, and ordered structures, the optimized processing parameters for the Fe-6.5wt.%Si alloys were the temperature and strain rate of higher than 900 °C and 0.01–10 s-1, respectively, or 800–900 °C and lower than 0.4 s-1, respectively.


2017 ◽  
Vol 898 ◽  
pp. 1134-1139
Author(s):  
Xue Fei Li ◽  
Ai Xue Sha ◽  
Xu Huang ◽  
Li Jun Huang

The hot deformation behavior of TC27 titanium alloy at the temperatures of 900-1150 °C and the strain rate of 0.01-10 s-1, the height reduction of 70%, was investigated in the isothermal compression test to identify the optimal extrusion parameters. The processing-map of TC27 titanium alloy was constructed based on dynamic materials model (DMM) and principle of Prasad*s instability. The conclusion shows that temperature and strain rate of deformation had a great influence on flow stress. At the beginning of deformation, the flow stress increased quickly with the augment of true strain and decreased slowly after flow stress reaching to the maximum value. Finally, flow stress tended to relatively stable condition. The flow stress decreased with the increase of temperature and increased with the increase of strain rate. The TC27 titanium alloy was sensitive to temperature and strain rate. Processing-map exhibited two peak efficiencies of power dissipation; one peak was 49% at 900°C/0.01 s-1, which dynamic recovery occured. The other peak was also 49% at 1050 °C /0.01s-1, which dynamic recrystallization occured in the domain. Besides, there were two instability areas in the processing-map which should be avoided during the extrusion. Therefore, in order to obtain the satisfactory properties, the parameters that 1050 °C and 0.01 s-1 were selected in the extrusion.


2020 ◽  
Vol 831 ◽  
pp. 25-31
Author(s):  
Pan Fei Fan ◽  
Jian Sheng Liu ◽  
Hong Ping An ◽  
Li Li Liu

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.


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