scholarly journals Characterization of Hot Deformation Behavior in a 13% Chromium Steel

2018 ◽  
Vol 941 ◽  
pp. 458-467
Author(s):  
Nima Safara Nosar ◽  
Fredrik Sandberg ◽  
Göran Engberg

The behavior of a 13% chromium steel subjected to hot deformation has been studied by performing hot compression tests in the temperature range of 850 to 12000C and at strain rates from 0.01 to 10 s-1. The uniaxial hot compression tests were performed on a Gleeble thermo-mechanical simulator. The best function that fits the peak stress for the material and its relation to the Zener-Hollomon parameter (Z) is derived. The average activation energy of this alloy in the entire test domain was found to be about 557 [kJmol-1] and the dynamic recrystallization (DRX) kinetics was studied to find the fraction DRX during deformation.

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1940 ◽  
Author(s):  
Jianmei Kang ◽  
Yuhui Wang ◽  
Zhimeng Wang ◽  
Yiming Zhao ◽  
Yan Peng ◽  
...  

Hot deformation behavior of Fe-30Mn-0.11C steel was investigated. Hot compression tests were carried out at various temperatures ranging from 800 °C to 1200 °C and at different strain rates of 0.01 s−1 to 10 s−1. The constitutive equation based on peak stress was established. Hot processing maps at different strains and recrystallization diagrams were also established and analyzed. The results show that dynamic recrystallization easily occur at high deformation temperatures and low strain rates. Safe and unstable zones are determined at the true strain of 0.6 and 0.7, and the hot deformation process parameters of partial dynamic recrystallization of the tested steel are also obtained.


2010 ◽  
Vol 139-141 ◽  
pp. 545-548 ◽  
Author(s):  
Shu Li Sun ◽  
Min Gang Zhang ◽  
Wen Wu He ◽  
Jun Qi Zhou ◽  
Gang Sun

The hot deformation behavior of as-cast AZ31 magnesium alloys have been investigated at 200~400°C and strain rates 0.001~1s-1 by means of hot compression tests on a Gleeble-1500D thermal-mechanical simulator. We have analyzed the flow stress-strain curve and presented the constitutive equation by calculating stress exponent, activation energy and Zemer-Hollomon parameter. Then, the processing map of AZ31 alloys has been developed based on the dynamic material model theories and Prasad instability criterion. The flow instability domain is observed at lower temperature and the larger power dissipation rate is emerging at 300~400°C. We have analyzed the corresponding deformation microstructures and it is characteristic of dynamic recrystallization. These results have shown that AZ31 alloy has good workability at 300~400°C and lower strain rate.


2016 ◽  
Vol 35 (6) ◽  
pp. 599-605 ◽  
Author(s):  
Fuqiang Zhen ◽  
Jianlin Sun ◽  
Jian Li

AbstractThe flow behavior of 3104 aluminum alloy was investigated at temperatures ranging from 250°C to 500°C, and strain rates from 0.01 to 10 s−1 by isothermal compression tests. The true stress–strain curves were obtained from the measured load–stroke data and then modified by friction and temperature correction. The effects of temperature and strain rate on hot deformation behavior were represented by Zener–Hollomon parameter including Arrhenius term. Additionally, the influence of strain was incorporated considering the effect of strain on material constants. The derived constitution equation was applied to the finite element analysis of hot compression. The results show that the simulated force is consistent with the measured one. Consequently, the developed constitution equation is valid and feasible for numerical simulation in hot deformation process of 3104 alloy.


Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 22
Author(s):  
Weiqi Kang ◽  
Yi Yang ◽  
Sheng Cao ◽  
Lei Li ◽  
Shewei Xin ◽  
...  

The hot deformation behavior of a new Al–Mn–Sc alloy was investigated by hot compression conducted at temperatures from 330 to 490 °C and strain rates from 0.01 to 10 s−1. The hot deformation behavior and microstructure of the alloy were significantly affected by the deformation temperatures and strain rates. The peak flow stress decreased with increasing deformation temperatures and decreasing strain rates. According to the hot deformation behavior, the constitutive equation was established to describe the steady flow stress, and a hot processing map at 0.4 strain was obtained based on the dynamic material model and the Prasad instability standard, which can be used to evaluate the hot workability of the alloy. The developed hot processing diagram showed that the instability was more likely to occur in the higher Zener–Hollomon parameter region, and the optimal processing range was determined as 420–475 °C and 0.01–0.022 s−1, in which a stable flow and a higher power dissipation were achieved.


2014 ◽  
Vol 511-512 ◽  
pp. 63-69
Author(s):  
Rui Jia ◽  
Fu Zhong Wang

Deformation behavior of steel 33Μn2v for oil well tube was studied by hot compression tests conducted at various temperatures and strain rates.The Kumar model was developed to predict the hot deformation behavior of steel 33Mn2V for oil well tube.In this regard,the hot compression tests were carried out at the temperatures from 750°C to 1200°C and at the strain rates of 0.02s1 to 0.16 s1.The experimental data were then used to determine the constants of developed constitutive equations. The Kumar model can be represented by ZenerHollomon parameter in a hyperbolic sinusoidal equation form.The apparent activation energy of deformation is calculated to be 342.1481kJ/Mol.Dynamic recrystallization of steel 33Mn2V occur and the completion of the critical deformation is small,termination error and the initial deformation is smaller.Therefore,its easy for the steel 33Mn2V to the occurrence and completion of dynamic recrystallization.


Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1020 ◽  
Author(s):  
Kristina Kittner ◽  
Madlen Ullmann ◽  
Thorsten Henseler ◽  
Rudolf Kawalla ◽  
Ulrich Prahl

In the present work, the microstructure, texture, mechanical properties as well as hot deformation behavior of a Mg-2Zn-1Al-0.3Ca sheet manufactured by twin roll casting were investigated. The twin roll cast state reveals a dendritic microstructure with intermetallic compounds predominantly located in the interdendritic areas. The twin roll cast samples were annealed at 420 °C for 2 h followed by plane strain compression tests in order to study the hardening and softening behavior. Annealing treatment leads to the formation of a grain structure, consisting of equiaxed grains with an average diameter of approximately 19 µm. The twin roll cast state reveals a typical basal texture and the annealed state shows a weakened texture, by spreading basal poles along the transverse direction. The twin roll cast Mg-2Zn-1Al-0.3Ca alloy offers a good ultimate tensile strength of 240 MPa. The course of the flow curves indicate that dynamic recrystallization occurs during hot deformation. For the validity range from 250 °C to 450 °C as well as equivalent logarithmic strain rates from 0.01 s−1 to 10 s−1 calculated model coefficients are shown. The average activation energy for plastic flow of the twin roll cast and annealed Mg-2Zn-1Al-0.3Ca alloy amounts to 180.5 kJ/mol. The processing map reveals one domain with flow instability at temperatures above 370 °C and strain rates ranging from 3 s−1 to 10 s−1. Under these forming conditions, intergranular cracks arose and grew along the grain boundaries.


2011 ◽  
Vol 314-316 ◽  
pp. 1159-1162
Author(s):  
Hai Yan Zhang ◽  
Shi Hong Zhang ◽  
Ming Cheng

The effect of δ phase content on the hot deformation behavior of alloy IN718 has been investigated using isothermal compression tests. The results indicated that the δ phase has a significant effect on the deformation behavior of alloy IN718 during hot working. After the peak stress, the decreasing speed of the stress raises as the increase in the δ phase content. The deformation activation energy for alloy IN718 increases with the raise of the δ phase content. And the peak strain for the alloy decreases with the increase of the δ phase content, which indicates that the δ phase can stimulate the occurrence of dynamic recrystallization during hot working.


Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 846 ◽  
Author(s):  
Changmin Li ◽  
Yuan Liu ◽  
Yuanbiao Tan ◽  
Fei Zhao

The H13-mod steel optimized by composition and heat treatment has reached the performance index of the shield machine hob. The hot deformation behavior of the H13-mod steel was investigated by compression tests in the temperature range from 900 to 1150 °C and the strain rate range from 0.01 to 10 s−1. The true stress-strain curve showed that the rising stress at the beginning of deformation was mainly caused by work hardening. After the peak stress was attained, the curve drop and the flow softening phenomenon became more obvious at low strain rates. The flow behavior of the H13-mod steel was predicted by a strain-compensated Arrhenius-type constitutive equation. The relationship between the material constant in the Arrhenius-type constitutive equation and the true strain was established by a sixth-order polynomial. The correlation coefficient between the experimental value and the predicted value reached 0.987, which indicated that the constitutive equation can accurately estimate the flow stress during the deformation process. A good linear correlation was achieved between the peak stress (strain), critical stress (strain) and the Zener‒Hollomon parameters. The processing maps of the H13-mod steel under different strains were established. The instability region was mainly concentrated in the high-strain-rate region; however, the microstructure did not show any evidence of instability at high temperatures and high strain rates. Combined with the microstructure and electron backscattered diffraction (EBSD) test results under different deformations, the optimum hot working parameters were concluded to be 998–1026 °C and 0.01–0.02 s−1 and 1140–1150 °C and 0.01–0.057 s−1.


2013 ◽  
Vol 721 ◽  
pp. 82-85
Author(s):  
Jian Bin Zhang ◽  
Dong Mei Yu ◽  
Shao Rui Niu ◽  
Gen Shun Ji

The hot deformation behavior and microstructure evolution of 430 ferritic stainless steel (430 FSS) were investigated within the temperature range of 950°C~1150°C at the strain rate of 0.01 s-1, 0.1 s-1, and 1.0 s-1using a thermo-mechanical simulator. The effects of temperature and strain rate on the flow behavior and microstructures of 430 ferritic stainless steel at reduction ratio 50 % were analyzed. Results indicated that the apparent stress exponent and the apparent activation energy of the steel were about 1.08 and 344 kJ/mol, respectively. The hot deformation equation of 430 was considered as. There was a relationship between the softening mechanism and Zener-Hollomon parameter (abbreviated Z). With the Z value increasing from 4.30×1010to 5.00×1014, the hot deformation peak stress correspondingly increased from 10.74 MPa to 76.02MPa.


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