Mathematical Model of Hot Deformation Resistance of X120 Pipeline Steel

2012 ◽  
Vol 538-541 ◽  
pp. 1724-1731
Author(s):  
Hong Wei Zheng ◽  
Di Tang ◽  
Hui Bin Wu ◽  
Liu Yang
Keyword(s):  
Mathematical Model ◽  
Deformation Rate ◽  
Deformation Temperature ◽  
Pipeline Steel ◽  
Deformation Resistance ◽  
Effect Of Temperature ◽  
Temperature Deformation ◽  
Test Machine ◽  
Deformation Degree ◽  
The Mathematical Model

The high-temperature deformation resistance of X120 pipeline steel was studied under different deformation temperature and different deformation rate through the hot compression test on the Gleeble-3500 thermal/mechanics simulation test machine. The influence of deformation degree, deformation temperature and deformation rate on deformation resistance was thoroughly investigated. The deformation resistance of X120 pipeline steel increased slowly when deformation degree was higher than 0.2. With the increase of deformation temperature, the work-hardening effect was weakened, so the deformation resistance decreased. And the deformation rate had dual influences on the deformation resistance, including the effect of temperature and time. Based on the experiment data, the parameters in the mathematical model were regressed by using SPSS (Statistic Package for Social Science), and the mathematical model of the deformation resistance of X120 pipeline steel was established finally. Through the regression analysis, the model had been proved to have great matching precision.

The Mathematic Model of Deformation Resistance of S50C Medium Carbon Steel in Hot Rolling Process

2013 ◽  
Vol 652-654 ◽  
pp. 2043-2047
Author(s):  
Jing Long Liang ◽  
Yun Li Feng ◽  
Jin Zhi Yin ◽  
Da Qiang Cang ◽  
Hui Li
Keyword(s):  
Carbon Steel ◽  
Hot Rolling ◽  
Deformation Rate ◽  
Deformation Temperature ◽  
Rolling Process ◽  
Medium Carbon Steel ◽  
Deformation Resistance ◽  
Deformation Degree ◽  
Medium Carbon ◽  
Hot Rolling Process

A test study of deformation resistance of S50C medium carbon steel in hot rolling process was conducted by using Gleeble 3500 Thermal-mechanical testing machine. The relationship of deformation resistance with different deformation temperature and deformation rate and deformation degree was analyzed through the stress-strain curve of S50C medium carbon steel which measured in the test. The results show that the deformation resistance increase with decrease of deformation temperature and increase of deformation rate and deformation degree. The math model of plastic deformation for metal of tested steel is established by using 1stopt software with multi-component non-regression. The model is proved has good curve fitting characteristics though a regression analysis of the model, it can be used provide theory basis for the formulation of rolling process and calculation of the mechanical parameters.

The Mathematical Model of the Relation among the Resistance, the Distortion Temperature and the Rate of the Steel in the Plastic Deformation

2012 ◽  
Vol 502 ◽  
pp. 184-188
Author(s):  
Hong Li ◽  
Xiao Lin You
Keyword(s):  
Mathematical Model ◽  
Plastic Deformation ◽  
Tensile Strength ◽  
Basic Theory ◽  
Deformation Resistance ◽  
Deformation Degree ◽  
Plastic Processing ◽  
Hardening Curve ◽  
Fundamental Equations ◽  
The Mathematical Model

the hardening curve of the steel in the plastic deformation only considers the influence of the deformation degree on the resistance. This paper, according to the basic theory of plastic processing, proposes out the respective relation between the deformation resistance and the deformation degree, the temperature, as well as the rate. This paper gets the curves of these relations by experiments, summarizes the fundamental equations by simulation and finally deduces the plastic conditional equations relating to the material performance----the tensile strength.

scholarly journals On using the rotor acceleration mode to increase the accuracy of a two-stage gyrocompass

2020 ◽  
pp. 5-13
Author(s):  
Volodymyr Fedorov ◽  
Vladislav Kikot ◽  
Nataliya Shtefan
Keyword(s):  
Mathematical Model ◽  
Initial Position ◽  
Effect Of Temperature ◽  
Two Stage ◽  
Best Estimate ◽  
Torsion Suspension ◽  
Measured Angle ◽  
State Position ◽  
Acceleration Mode ◽  
The Mathematical Model

The article considers a two-stage gyrocompass with a rigid torsion suspension of the moving part. The principle of its action is based on balancing the elastic moment of the torsion bars with the gyroscopic moment. When this condition is met, the azimuth of the steady-state position of the rotor axis is calculated from the known kinetic moment , latitude and angular rigidity of the torsion bars, and the measured angle of rotation of the moving part of the gyroscope relative to its initial position. The “aging of the material” of the torsion bars, the effect of temperature on them, etc., leads to an uncontrolled change in the angular stiffness of the torsion bars, which, in turn, leads to an error in determining the position of the meridian. A method is proposed for determining the position of the meridian under conditions when the angular stiffness of the torsion is unknown. The method involves observing the motion of the gyroscope in a mode where the kinetic momentum changes linearly (the rotor accelerates). This movement is associated with the movement of the mathematical model of a two-stage gyrocompass in the same mode in the form of a differential equation of motion or in the form of its solution. As a result of minimizing the discrepancy between the real movement of the gyrocompass and the movement of its mathematical model, the “best estimate” of the parameter characterizing the position of the meridian and the “best estimate” of the angular stiffness of the torsion bars in this dimension are found. The results of modeling the corresponding information processing algorithms are considered. The advantages of the proposed method compared with traditional methods are indicated .

scholarly journals Comparative Study on Constitutive Models for 21-4N Heat Resistant Steel during High Temperature Deformation

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1893 ◽  
Author(s):  
Yiming Li ◽  
Hongchao Ji ◽  
Zhongman Cai ◽  
Xuefeng Tang ◽  
Yaogang Li ◽  
...  
Keyword(s):  
Prediction Accuracy ◽  
Coupling Effect ◽  
Equivalent Stress ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Deformation Condition ◽  
Test Machine ◽  
Isothermal Compression ◽  
Ann Model ◽  
Deformation Degree

The Gleeble-1500D thermal simulation test machine was used to conduct the isothermal compression test on 21-4N at the strain rate ( ε ˙ ) of 0.01–10 s−1, the deformation temperature (T) of 1273–1453 K and the maximum deformation is 0.916. The data of the stress-strain (σ-ε) were obtained. Based on the σ-ε data, the Johnson-Cook (J-C), modified J-C, Arrhenius and Back-Propagation Artificial Neural Network (BP-ANN) models were established. The accuracy of four models were verified, analyzed and compared. The results show that J-C model has a higher accuracy only under reference deformation conditions. When the deformation condition changes greatly, the accuracy of J-C model is significantly reduced. The coupling effect of T and ε ˙ of modified J-C model is considered, and the prediction accuracy is greatly improved The Arrhenius model introduces Zener-Hollomon (Z) to represent the coupling effect of T and ε ˙ , it has a fairly high prediction accuracy. And it can predict flow stress (σ) accurately at different conditions. The accuracy of BP-ANN model is the highest, but its learning rate is low, the learning and memory are unstable. It has no memory for the weights and thresholds of the completed training. So, there are certain limitations of it in use. Finally, a Finite Element Method (FEM) of the isothermal compression experiment for four models were established, and the distribution of the equivalent stress field, equivalent strain field and temperature field with the deformation degree of 60% were obtained.

Establishment of Flow Stress Model of EW75 Alloy

2013 ◽  
Vol 423-426 ◽  
pp. 241-246
Author(s):  
Ming Long Ma ◽  
Kui Zhang
Keyword(s):  
Mathematical Model ◽  
Flow Stress ◽  
Magnesium Alloy ◽  
Strain Rate ◽  
Strain Rate Range ◽  
Strain Rates ◽  
Stress Strain ◽  
Deformation Degree ◽  
Maximum Deformation ◽  
The Mathematical Model

The behavior evolvement of Mg-7.22Gd-4.84Y-1.26Nd-0.58Zr (EW75) magnesium alloy during the hot deformation process was discussed. The flow stress behavior of magnesium alloy over the strain rate range 0.002s-1to 2s-1and the temperature range 623K to 773K had been researched on Gleeble-1500D hot simulator under the maximum deformation degree 60%. A mathematical model was established to predict the stress-strain curves of this alloy during deformation. The experimental results showed that the stress-strain curves were obviously affected by the strain rates and deformation temperatures. The mathematical model could predict the stress-strain curves when the strain rates were under 0.2-1, but there was significant error in some of stress-strain curves when the strain-rate was 2-1by the reason of deformation temperature rising.

The Effects of Rolling Process on Microstructures and Properties of High Nb X80 Grade Pipeline Steel

2013 ◽  
Vol 641-642 ◽  
pp. 538-542
Author(s):  
Xiao Yu Ye ◽  
Kai Hua Zhang ◽  
Jun Zuo
Keyword(s):  
Pipeline Steel ◽  
Rolling Process ◽  
Controlled Rolling ◽  
Thermal Simulation ◽  
Temperature Deformation ◽  
Test Scheme ◽  
Test Machine ◽  
Coiling Temperature ◽  
Controlled Cooling ◽  
Low Temperature Impact Toughness

In Gleele-3500 Thermal Simulation Test Machine，conduct Thermal Simulation Experiment for High Niobium X80 Grade Pipeline Steel at Different Deformation Temperature, Deformation Extent and Coiling Temperature. Analysis the Microstructure Was Influenced by Different Rolling Process. According to the Thermal Simulation Experiments, Designed Test Scheme of Controlled Rolling and Controlled Cooling and Completed the Trial. the Results Showed that: for High Niobium X80 Grade Pipeline Steel, the Microstructures Are Acicular Ferrite and Have Good Mechanical Properties. the Low Temperature Impact Toughness Are More than 300J in -20°C and -40°C.

The Effects of Rolling Process on Microstructures of High Nb X70 Grade Pipeline Steel

2011 ◽  
Vol 396-398 ◽  
pp. 177-181
Author(s):  
Xiao Yu Ye ◽  
Kai Hua Zhang ◽  
Jun Zuo
Keyword(s):  
Cooling Rate ◽  
Heating Temperature ◽  
Pipeline Steel ◽  
Rolling Process ◽  
Thermal Simulation ◽  
Temperature Deformation ◽  
Test Machine ◽  
Coiling Temperature ◽  
Simulation Test ◽  
Thermal Simulation Experiment

In Gleele-3500 thermal simulation test machine, conduct thermal simulation experiment for high niobium X70 grade pipeline steel at different heating temperature, deformation temperature, deformation extent, cooling rate and coiling temperature. Analysis that the microstructure was influenced by different heating temperature and rolling process. The results showed that, For high niobium X70 grade pipeline steel, controlled heating temperature was1200±20°C, using HTP process, in large cooling rate range all can get the uniform acicular ferrite microstructures.

scholarly journals Comparative Study on Constitutive Models for 21-4N Heat Resistant Steel During High Temperature Deformation

2019 ◽  
Author(s):  
Yiming Li ◽  
Hongchao Ji ◽  
Zhongman Cai ◽  
Xuefeng Tang ◽  
Yaogang Li ◽  
...  
Keyword(s):  
Prediction Accuracy ◽  
Coupling Effect ◽  
Equivalent Stress ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Deformation Condition ◽  
Test Machine ◽  
Isothermal Compression ◽  
Ann Model ◽  
Deformation Degree

The Gleeble-1500D thermal simulation test machine was used to conduct the isothermal compression test on 21-4N at the strain rate ( ) of 0.01-10s-1, the deformation temperature (T) of 1273-1453K and the maximum deformation is 0.916. The data of the stress-strain ( - )were obtained. Based on the - data, the Johnson-Cook (J-C), modified J-C, Arrhenius and Back-Propagation Artificial Neural Network (BP-ANN) models were established. The accuracy of four models were verified, analyzed and compared. The results show that J-C model has a higher accuracy only under reference deformation conditions. When the deformation condition changes greatly, the accuracy of J-C model is significantly reduced. The coupling effect of T and of modified J-C model is considered, and the prediction accuracy is greatly improved The Arrhenius model introduces Zener-Hollomon (Z) to represent the coupling effect of T and , it has a fairly high prediction accuracy. And it can predict flow stress ( ) accurately at different conditions. The accuracy of BP-ANN model is the highest, but its learning rate is low, the learning and memory are unstable. It has no memory for the weights and thresholds of the completed training. So, there are certain limitations of it in use. Finally, a FEM of the isothermal compression experiment for four models were established, and the distribution of the equivalent stress field, equivalent strain field and temperature field with the deformation degree of 60% were obtained.

scholarly journals Plasticity and deformation resistance of the alloyed rail steels in rolling temperature interval

2019 ◽  
Vol 62 (6) ◽  
pp. 452-460 ◽  
Author(s):  
A. A. Umanskii ◽  
A. V. Golovatenko ◽  
A. S. Simachev ◽  
V. V. Dorofeev ◽  
T. N. Oskolkova
Keyword(s):  
Deformation Rate ◽  
Deformation Temperature ◽  
Rail Steel ◽  
Central Zone ◽  
Deformation Resistance ◽  
Coarse Grained ◽  
Regression Equations ◽  
Surface Layers ◽  
Metallic Inclusions ◽  
Continuously Cast

On the basis of conducted experimental studies, regularities of the influence of temperature-speed rolling conditions on the plasticity and deformation resistance in the zones of continuously cast billets of alloy rail steels of E76KhF, E76KhSF grades are determined and scientifically substantiated. The results indicate the complex nature of dependence of rail steel E76KhF plasticity on deformation temperature. In particular, for near-surface layers of continuously cast billets, a noticeable decrease in plasticity in the temperature range of 1025 – 1075 °Cwas recorded, which is absent for the layers located in central zone of that billets. Generalization of the results of plasticity studies of various layers of continuously cast rail E76KhF steel billets has shown that absolute values of the plasticity criterion are significantly reduced with the distance from the surface to the central zone. This fact can be explained by a coarse-grained structure and increased concentration of non-metallic inclusions in the central zone of continuously cast billets relative to their surface layers; it was confirmed by the results of metallographic studies. In particular, it was found that the average grains diameter in the surface layer of deformed continuously cast billets is in 1.3 – 2.1 times less compared to the central zone. There was confirmed the presence of significant concentrations of non-deformable inclusions of the silicate type (Al2O3· SiO2 ; FeO·SiO2 ; MnO·SiO2 ), which have most negative influence on steel plasticity while in the surface area such inclusions are absent. On the basis of conducted researches it was established that with increase in deformation temperature of rail steel E76KhSF there is a decrease in resistance to plastic deformation according to the exponential law. In this case, absolute values of the steel deformation resistance are reduced with the distance from the surface to the central zone of continuously cast billets, which is associated with the above illustrated increase in grain size and localization of non-metallic inclusions. The revealed tendency to reduce the deformation resistance from the surface layers to the center of continuously cast billets is maintained regardless to deformation rate, while the absolute values of the deformation resistance increase significantly with the growth of deformation rate from 1 to 10 s–1. Mathematical processing of the obtained experimental data allowed to obtain regression equations that help to predict plastic and deformation properties of alloyed rail steels of E76KhF and E76KhSF grades with a sufficient degree of reliability under the specified rolling conditions and are complex theoretical basis for the development and improvement of new heating modes of billets for rolling and rail rolling schemes. Adequacy of the obtained experimental dependences is confirmed by results of pilot industrial testing of the new mode of railway rails production on the universal rail mill of “EVRAZ ZSMK”.

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