scholarly journals Strain Modified Constitutive Equation and Processing Maps of High Quality 20MnCr5(SH) Gear Steel

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 536
Author(s):  
Jingcheng Yang ◽  
Lizhong Wang ◽  
Yingjun Zheng ◽  
Zhiping Zhong
Keyword(s):  
High Temperature ◽  
Constitutive Equation ◽  
Strain Rate ◽  
Strain Curve ◽  
Strain Rate Range ◽  
Instability Criterion ◽  
Processing Maps ◽  
High Quality ◽  
Prediction Ability ◽  
Gear Steel

In order to develop the high-temperature forging process of high-quality 20MnCr5(SH) gear steel, according to the physical characteristics of high-temperature hot deformation of 20MnCr5(SH), the single pass hot pressing test was carried out in the temperature range of 930–123 °C and the strain rate range of 0.002–2s−1 by using a Gleeble-1500D thermal simulator. The stress-strain curve of 20MnCr5(SH) was analyzed and confirmed by microstructure analysis. The dynamic recrystallization occurred, and the constitutive equation of 20MnCr5(SH) high temperature flow stress was established. Considering that the traditional Arrhenius constitutive equation does not consider the effect of strain on the constitutive equation, a strain modified Arrhenius constitutive equation is proposed. The results show that the correlation is 0.9895 and the average relative error is 8.048%, which verifies the stress prediction ability of the strain modified constitutive equation. According to the dynamic material theory and instability criterion, the processing maps of 20MnCr5(SH) are obtained. It is therefore considered that 20MnCr5(SH) is most suitable for thermoplastic processing at strain rate of 0.05–1s−1 and temperature of 1030–1100 °C.

Study on High Temperature Deformation Characteristics of BTi-62421S

2011 ◽  
Vol 704-705 ◽  
pp. 141-146
Author(s):  
Hui Fang Zhang ◽  
Zhi Min Zhang ◽  
Xing Zhang ◽  
Bao Cheng Li ◽  
Hong Hai Ma
Keyword(s):  
High Temperature ◽  
Constitutive Equation ◽  
Strain Rate ◽  
Hot Deformation ◽  
Strain Curve ◽  
Strain Rate Range ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Softening Mechanism ◽  
Β Phase

In the paper, the high-temperature compression test of BTi-62421S alloy was carried out in the temperature range from 850°C to 1050°C, strain rate range from 0.01 s-1to 30 s-1, and the deformation of 70%. The results show that the flow stress of BTi-62421S alloy significantly increased with the decreasing of the temperature and the increasing of the strain rate. By calculating the activation energy of deformation and analyzing the stress-strain curve, it can be seen that the softening mechanism of hot deformation of BTi-62421S alloy is different near the （α+β）/β phase transforming temperature. The softening mechanism of hot deformation is mainly dynamic recrystallization in （α+β） area and it is mainly dynamic recovery above β phase transforming temperature. According to hyperbolic sine model, the alloy’s constitutive equation is established. Key word: BTi-62421S alloy; high temperature figuration; constitutive equation

Influences of Strain Rate and Deformation Temperature on Flow Stress and Dynamic Recrystalliazation of Heat Resistant Steel P91

2011 ◽  
Vol 217-218 ◽  
pp. 958-963
Author(s):  
Xue Qin Jin ◽  
Da Sen Bi ◽  
Jian Zhang ◽  
Xiao Lan Wang ◽  
Jian Hua Song ◽  
...  
Keyword(s):  
High Temperature ◽  
Flow Stress ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Strain Curve ◽  
Strain Rate Range ◽  
Thick Wall ◽  
Resistant Steel ◽  
Heat Resistant Steel ◽  
Heat Resistant

In power station big caliber thick wall seamless tube typical steel P91for example, The hot deformation behavior and heat flow stress-strain curve of the heat resistant steel P91was investigated with a compression test on Gleeble3500 simulator at a temperature range of 1050°C～1200°C and strain rate range of 10-4～5s-1. The test curve shows that P91 materials have the dynamic recrystallization and recovery behavior in high temperature and deformation. With the rise of temperature and strain rate of decreased, flow stress is lower and the dynamic recrystallization phenomenon is easier to occur. By metalloscope observed, in the high temperature and low strain rate conditions, the dynamic recrystallization area and new nucleation grain size are larger, and microstructure is more uniformly distributed.

scholarly journals Determination of Constitutive Equation and Thermo–Mechanical Processing Map for Pure Iridium

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1087
Author(s):  
Mi Zhou ◽  
Rui Hu ◽  
Jieren Yang ◽  
Chuanjun Wang ◽  
Ming Wen
Keyword(s):  
Constitutive Equation ◽  
Strain Rate ◽  
Processing Map ◽  
Frictional Coefficient ◽  
Strain Curve ◽  
Strain Rate Range ◽  
Forming Process ◽  
Thermal Compression ◽  
Rate Range ◽  
Temperature Range

Deformation behavior of pure iridium has been studied during thermal compression testing with the help of Gleeble-1500D in the temperature range of 1200 °C~1500 °C and strain rate range of 10−1 s−1~10−2 s−1. Resistance to deformation, microstructural evolution and hot workability of pure iridium have been used to analyze in detail. Frictional coefficient has been used to modify the experimental stress–strain curve of thermal compression test, and it has been found effective in reducing the influence of friction during thermo–mechanical testing. The hyperbolic sine constitutive equation of pure iridium has been established to give a material processing model for numerical simulation. A very high value of activation energy for iridium, 573 KJ/mol, clearly indicates that it is very hard to deform this material. The deformation mechanism of pure iridium is dependent upon temperature as well as strain rate. At low temperature and strain rate (temperature range of 1200 °C~1300 °C and strain rate range of 10−1 s−1~10−2 s−1), dynamic recovery is active while dynamic recrystallization becomes operative as temperature and stain rate are increased. On further increase in temperature and decrease in strain rate (temperature range of 1400 °C~1500 °C and strain rates of 10−2 s−1~10−3 s−1), abnormal grain growth takes place. On the basis of a constitutive model and processing map, suitable forming process parameters (temperature range of 1400 °C~1500 °C and strain rate range of 0.1 s−1~0.05 s−1) for pure iridium have been worked out.

Hot Deformation Behavior and Processing Map of a New High-Temperature Titanium Alloy

2017 ◽  
Vol 898 ◽  
pp. 566-573
Author(s):  
Shao Hui Shi ◽  
Li Hua Chai ◽  
Tao Li ◽  
Yong Shuang Cui ◽  
Guo Dong Shi ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
High Temperature ◽  
Strain Rate ◽  
Deformation Behavior ◽  
Constant Strain Rate ◽  
Strain Rate Range ◽  
Instability Criterion ◽  
Engineering Strain ◽  
Rate Range ◽  
Temperature Range

Isothermal constant strain rate compression testing of a new as-cast high-temperature titanium alloy Ti-6.5Al-11.5(Sn,Zr)-2.5(Mo,W,Nb)-0.25Si-0.1Er was carried out at the deformation temperatures range from 900°C to 1100°C, strain rate range from 0.001 to 1 s-1 and 60% of engineering strain. The deformation behavior of this high-temperature titanium alloy was analyzed based on the stress-strain result, and the constitutive equation based on the hyperbolic sine model and the parameters of Zener–Hollomon was established, showing a close accordance with the experimental value. The hot processing maps based on the dynamic material model and the Prasad’s instability criterion were constructed at strains of 0.3 and 0.6. The maps exhibit two stable deformation domains in the temperature range of 940~960°C and strain rate range of 0.001~0.002s-1, and in the temperature range of 1030~1070°C and strain rate range of 0.02~0.06s-1 with the power dissipation efficiency of 58.5% and 54.5%, respectively.

A Comparative Study on Modeling of High Temperature Rheological Behavior of AZ80 Magnesium Alloy Using Artificial Neural Network and Inverse Method

2012 ◽  
Vol 522 ◽  
pp. 136-141
Author(s):  
Yan Lou ◽  
Luo Xing Li
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
High Temperature ◽  
Strain Rate ◽  
Rheological Behavior ◽  
Inverse Method ◽  
Strain Rate Range ◽  
Compression Tests ◽  
Prediction Ability ◽  
Artificial Neural

Artificial neural network (ANN) and inverse method were employed in modeling the rheological behavior of the AZ80 magnesium. The hot deformation behavior of extruded AZ80 magnesium was investigated by compression tests in the temperature 350-450 and strain rate range 0.01-50 s-1. Investigation of flow stress curves and microstructure of the compression specimen illustrate occurrence of dynamic recrystallization. The inverse method of non-liner regression was used to determine the parameters of the suggested constitutive equation. The maximum relative errors at different temperatures and different strain rates between experimental and predicted flow stresses by ANN and inverse method were compared. The results show the ANN derives statistical models have better similar prediction ability to those of inverse method, especially at high strain rate. This indicates that ANN can be used as an alternative modeling tool for high temperature rheological behavior studies.

Flow Behavior and Workability of a Zn-8Cu-0.2Cr Alloy during Hot Deformation

2012 ◽  
Vol 538-541 ◽  
pp. 1257-1261
Author(s):  
Sheng Li Guo ◽  
Peng Du ◽  
Xiao Ping Wu ◽  
De Fu Li
Keyword(s):  
Constitutive Equation ◽  
Strain Rate ◽  
Hot Deformation ◽  
Flow Instability ◽  
Flow Behavior ◽  
Strain Rate Range ◽  
Processing Maps ◽  
Compression Tests ◽  
Rate Range ◽  
Temperature Range

The hot deformation behavior of Zn91.8-Cu8-Cr0.2 (in wt.%) was investigated by means of hot compression tests in the temperature range of 230-380 °C and strain rate range of 0.01 - 10 s-1. The constitutive equation and processing maps were developed. The influence of strain on the flow stress was studied by considering the effect of the strain on material constants. The stress-strain curves obtained by the constitutive equation are in good agreement with experimental results. The proposed constitutive equations can be used for the analysis problem of hot forming processes. The processing maps have exhibited a domain, which is optimum processing window for hot working, in the temperature range of 310 - 380 °C and strain rate range of 0.01-1 s-1 corresponding to the higher efficiency of power dissipation. The large regime of flow instability is observed at high strain rate. The instability regime should be avoided during hot deformation processing.

Characterization of High Temperature Deformation Behavior of BFe10-1-2 Cupronickel Alloy Using Orthogonal Analysis

2017 ◽  
Vol 36 (7) ◽  
pp. 701-710
Author(s):  
Jun Cai ◽  
Kuaishe Wang ◽  
Xiaolu Zhang ◽  
Wen Wang
Keyword(s):  
High Temperature ◽  
Flow Stress ◽  
Constitutive Equation ◽  
Strain Rate ◽  
Deformation Behavior ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Compression Tests ◽  
Statistical Parameters ◽  
Orthogonal Analysis

AbstractHigh temperature deformation behavior of BFe10-1-2 cupronickel alloy was investigated by means of isothermal compression tests in the temperature range of 1,023~1,273 K and strain rate range of 0.001~10 s–1. Based on orthogonal experiment and variance analysis, the significance of the effects of strain, strain rate and deformation temperature on the flow stress was evaluated. Thereafter, a constitutive equation was developed on the basis of the orthogonal analysis conclusions. Subsequently, standard statistical parameters were introduced to verify the validity of developed constitutive equation. The results indicated that the predicted flow stress values from the constitutive equation could track the experimental data of BFe10-1-2 cupronickel alloy under most deformation conditions.

scholarly journals A Modified Fractional Maxwell Numerical Model for Constitutive Equation of Mn-Cu Damping Alloy

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2020
Author(s):  
Baoquan Mao ◽  
Rui Zhu ◽  
Zhiqian Wang ◽  
Yuying Yang ◽  
Xiaoping Han ◽  
...  
Keyword(s):  
Constitutive Equation ◽  
Strain Rate ◽  
Constitutive Relation ◽  
Constant Strain Rate ◽  
Strain Curve ◽  
Maxwell Model ◽  
Nonlinear Viscoelastic ◽  
Fractional Maxwell Model ◽  
Hysteretic Characteristics ◽  
Nonlinear Elastic

To better describe its constitutive relation, we need a new constitutive equation for an important nonlinear elastic material, Mn-Cu damping alloy. In this work, we studied the nonlinear and hysteretic characteristics of the stress-strain curve of the M2052 alloy with the uniaxial cyclic tensile test with constant strain rate. The strain rate and amplitude correlations of M2052 resembled those of nonlinear viscoelastic material. Therefore, we created a new constitutive equation for the M2052 damping alloy by modifying the fractional Maxwell model, and we used the genetic algorithm to carry out numerical fitting with MATLAB. By comparing with the experimental data, we confirmed that the new constitutive equation could accurately depict the nonlinear constitutive relation and hysteretic property of the damping alloy. Taken together, this new constitutive equation for Mn-Cu damping alloy based on the fractional Maxwell model can serve as an effective tool for further studies of the constitutive relation of the Mn-Cu damping alloys.

scholarly journals Hot Deformation Behaviors of the Mg-3Sn-2Al-1Zn Alloy: Investigation on its Constitutive Equation, Processing Map, and Microstructure

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 312 ◽  
Author(s):  
Yuhang Guo ◽  
Yaodong Xuanyuan ◽  
Xuannam Ly ◽  
Sen Yang
Keyword(s):  
Constitutive Equation ◽  
Strain Rate ◽  
Processing Map ◽  
True Strain ◽  
Strain Rate Range ◽  
Hot Working ◽  
Microstructure Observation ◽  
Stability And Instability ◽  
Deformation Behaviors ◽  
Working Parameters

In this work, the Mg-3Sn-2Al-1Zn (TAZ321, wt. %) alloy with excellent high temperature resistance was compressed using a Gleeble-3500 thermo-mechanical simulator at a wide temperature and the strain rate range. The kinetics analyses showed that the dominant deformation mechanism was likely caused by the cross slipping of dislocations. A constitutive equation which expressed the relationship between the flow stress, deformation temperature, and strain rate was established, and the average activation energy Q was calculated to be 172.1 kJ/mol. In order to delineate the stability and instability working domains, as well as obtain the optimum hot working parameters of the alloy, the hot processing maps in accordance with Prassad’s criterion are constructed at the true strain of 0.2, 0.4, 0.6, and 0.8, respectively. Based on the hot processing map and microstructure observation, the optimum hot working parameter was determined to be 350 °C/1 s−1. The continuous fine dynamic recrystallization (CDRX) grains occurred in the optimum deformation zone. The predicted instability domains was identified as T = 200–300 °C, ε ˙ = 10−2–1 s−1, which corresponded to the microstructure of deformation twinning and micro cracks at the intersection of grain boundaries.

Mechanical Behavior and Constitutive Equation of Concrete under High-Temperature Dynamical Conditions

2011 ◽  
Vol 228-229 ◽  
pp. 303-308
Author(s):  
Bin Jia ◽  
Zheng Liang Li ◽  
Jun Lin Tao ◽  
Chun Tao Zhang
Keyword(s):  
High Temperature ◽  
Constitutive Equation ◽  
Strain Rate ◽  
Mechanical Behavior ◽  
Test Data ◽  
Dynamical Behavior ◽  
Hardening Effect ◽  
Failure Evolution ◽  
Different Temperatures ◽  
Strain Rate Hardening

SPHB tests of concrete under different temperatures and various loading conditions are completed, and high-temperature dynamical behavior of concrete is obtained. Dynamical mechanical behavior of concrete with high temperature is affected by not only the strain rate effect, but also the high temperature weakening effect, and the strain rate hardening effect is coupled with high temperature weakening effect, but the latter has greater influence. Concrete failure evolution is described on basis of the damage factor, the intercoupling strain rate hardening effect and temperature weakening effect are simply set as mutually independent factors, each parameter is respectively fitted with test data, finally, concrete constitutive equation under high-temperature dynamical conditions is established, and comparative analysis with test data are conducted, indicating good coincidence with test results.

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