The Hot Deformation Behavior and Hot Processing Map of CL60 Rail Wheel Steel

2012 ◽  
Vol 602-604 ◽  
pp. 2006-2010
Author(s):  
Fei Zhao ◽  
Yan Yan ◽  
Yong Hai Ren

The hot deformation behavior of CL60 rail wheel steel has been studied by employing both processing maps and microstructural observations. Tests are performed at temperatures of 800—1100°C and strain rates of 0.1s-1—5s-1 and the flow stress data obtained from the tests are used to develop processing maps. The microstructural evolution of deformed samples is also examined on the basis of optical microscopic observations. The result indicates that under experimental conditions this alloy shows dynamic recrystallization(RDX) characteristics during hot compression deformation. Both deformation temperatures and strain rates have obvious influence on flow stress and its corresponding peak strain, which increase gradually with decreasing temperature and increasing strain rate. RDX occurred at higher temperature and lower strain rate.

2016 ◽  
Vol 684 ◽  
pp. 35-41 ◽  
Author(s):  
S.V. Rushchits ◽  
E.V. Aryshensky ◽  
S.M. Sosedkov ◽  
A.M. Akhmed'yanov

The deformation behavior of 1565ch alloy under the plane-strain conditions in the temperature range of 350–490 оС and strain rates range of 0,1–10 s-1 is studied. The expression for steady flow stress as the functions of temperature of deformation and strain rate is obtained. It is established that 1565ch alloy with zirconium addition shows higher strain resistance and less tendency to dynamic and static recrystallization than AMg6.


2018 ◽  
Vol 37 (9-10) ◽  
pp. 873-888 ◽  
Author(s):  
Nitin Kotkunde ◽  
Hansoge Nitin Krishnamurthy ◽  
Swadesh Kumar Singh ◽  
Gangadhar Jella

AbstractA thorough understanding of hot deformation behavior plays a vital role in determining process parameters of hot working processes. Firstly, uniaxial tensile tests have been performed in the temperature ranges of 150 °C–600 °C and strain rate ranges of 0.0001–0.01s−1 for analyzing the deformation behavior of ASS 304 and ASS 316. The phenomenological-based constitutive models namely modified Fields–Backofen (m-FB) and Khan–Huang–Liang (KHL) have been developed. The prediction capability of these models has been verified with experimental data using various statistical measures. Analysis of statistical measures revealed KHL model has good agreement with experimental flow stress data. Through the flow stresses behavior, the processing maps are established and analyzed according to the dynamic materials model (DMM). In the processing map, the variation of the efficiency of the power dissipation is plotted as a function of temperature and strain rate. The processing maps results have been validated with experimental data.


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.


2013 ◽  
Vol 709 ◽  
pp. 143-147 ◽  
Author(s):  
Tao Wang ◽  
Zhao Li ◽  
Shu Hong Fu ◽  
Yong Zhang ◽  
Yu Xin Zhao ◽  
...  

The hot deformation behavior of U720Li was investigated by isothermal compression tests at temperature ranging from 1060-1180°C and strain rate from 0.001s-1 to 20s-1. The flow stress-strain curves and microstructures were investigated and a constitutive equation was established. It is found that flow stress is sensitive to stain rate and deformation temperature greatly. The higher stain rate resultes in a larger fluctuation in flow stress. The hot deformation activation energy is determined to be 552.8kJ/mol. Grain size increases with increasing temperature and decreases firstly and then increases with increasing strain rate. U720Li alloy should be deformed below the solve temperature of γ primary phase with lower strain rate in order to obtain the even and fine grain size.


2013 ◽  
Vol 17 (5) ◽  
pp. 1523-1528
Author(s):  
Bao-Hua Jia ◽  
Wei-Dong Song ◽  
Hui-Ping Tang ◽  
Jian-Guo Ning

Isothermal compression tests of TC18 titanium alloy at the deformation temperatures ranging from 25?C to 800?C and strain rate ranging from 10-4 to 10-2 s-1 were conducted by using a WDW-300 electronic universal testing machine. The hot deformation behavior of TC18 was characterized based on an analysis of the true stress-true strain curves of TC18 titanium alloy. The curves show that the flow stress increases with increasing the strain rate and decreases with increasing the temperature, and the strain rate play an important role in the flow stress when increasing the temperatures. By taking the effect of strain into account, an improved constitutive relationship was proposed based on the Arrhenius equation. By comparison with the experimental results, the model prediction agreed well with the experimental data, which demonstrated the established constitutive relationship was reliable and can be used to predict the hot deformation behavior of TC18 titanium alloy.


2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Ming-wei Guo ◽  
Zhen-hua Wang ◽  
Ze-an Zhou ◽  
Shu-hua Sun ◽  
Wan-tang Fu

316LN stainless steel with 0.08%N (08N) and 0.17%N (17N) was compressed at 1073–1473 K and 0.001–10 s−1. The hot deformation behavior was investigated using stress-strain curve analysis, processing maps, and so forth. The microstructure was analyzed through electron backscatter diffraction analysis. Under most conditions, the deformation resistance of 17N was higher than that of 08N. This difference became more pronounced at lower temperatures. The strain rate sensitivity increased with increasing temperature for types of steel. In addition, the higher the N content, the higher the strain rate sensitivity. Hot deformation activation energy increased from 487 kJ/mol to 549 kJ/mol as N concentration was increased from 0.08% to 0.17%. The critical strain for initiation of dynamic recrystallization was lowered with increasing N content. In the processing maps, both power dissipation ratio and unstable region increased with increasing N concentration. In terms of microstructure evolution, N promoted dynamic recrystallization kinetic and decreased dynamic recrystallization grain size. The grain growth rate was lower in 17N than in 08N during heat treatment. Finally, it was found that N favored twin boundary formation.


Author(s):  
Mei-ling Li ◽  
Wen-jin Gao ◽  
Ying-hao Zhou

Abstract The 60NiTi (Ni60wt%–Ti40wt%) intermetallic is a hard-to-process material. Understanding of hot deformation behavior is crucial for the hot working of 60NiTi. This work studied hot deformation behavior and corresponding microstructure of the hot isostatic pressed 60NiTi in the temperature range of 900 °C–1050 °C and at strain rates of 0.1, 0.01, and 0.001 s-1 through a hot compression test. The flow stress and microstructure were susceptible to the hot deformation parameters. The flow stress decreased with the increase in deformation temperature and decrease in strain rate. Work hardening occurred at a small strain, then followed by softening; finally, near-dynamic equilibrium was achieved between work hardening and softening. A constitutive equation was developed to describe the effects of strain rate and temperature on flow stress. Simulation of hot deformation via the finite element method revealed the workpiece’s inhomogeneous deformation. The deformation occurred mainly in the center area of the cylindrical sample, resulting in high stress and strain concentrations in this region and causing the equiaxial grains to be compressed into prolate grains. This work can provide guidance for the hot working, such as forging and hot rolling, of 60NiTi.


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.


2017 ◽  
Vol 36 (5) ◽  
pp. 467-475
Author(s):  
Rui Luo ◽  
Qi Zheng ◽  
Zhending Tang ◽  
Yongquan Yao ◽  
Guifang Xu ◽  
...  

AbstractHigh-temperature single-pass compression experiments were conducted on alloy 800H using a Gleeble 3500 thermal-mechanical simulation testing machine, and hot deformation behaviors at temperatures of 1,000–1,150 °C and strain rates of 0.01–1 s–1 were investigated. The results revealed that dynamic recrystallization (DRX) behavior occurred more easily under deformation conditions with relatively low strain rates and high deformation temperatures. By taking the influence of strain on the hot deformation behavior into consideration, a strain-dependent hyperbolic sine constitutive model was constructed. Based on this revised constitutive model, flow stress during deformation was predicted. The linear relation between the predicted value and the experimental result was as high as 0.99648, and the absolute average relative error was 2.019 %. Thus, it was demonstrated that the strain-dependent analysis provided a constitutive model that was able to precisely predict flow stress under experimental conditions.


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