scholarly journals Hysteresis Properties of Corroded High Strength Steel

2021 ◽  
Vol 248 ◽  
pp. 01024
Author(s):  
Hong Wang
Keyword(s):  
Constitutive Model ◽  
High Strength Steel ◽  
Peak Stress ◽  
High Strength ◽  
Corrosion Damage ◽  
Cyclic Hardening ◽  
Hysteresis Curve ◽  
Skeleton Curve ◽  
Cyclic Loading Tests ◽  
Hysteresis Properties

In order to study the effects of corrosion damage on the hysteresis properties of high strength steel (HSS), dry-wet cycle corrosion tests were conducted on Q690D steel to obtain 6 batches of corroded specimens, and cyclic loading tests were performed on them to analyse the degradation law of hysteresis curve, skeleton curve and hysteretic energy, and then establish the hysteresis constitutive model of corroded HSS steel. Results indicated that although the hysteresis curves of corroded specimens are still smooth and full, corrosion damage would result in the continuous decrease of peak stress, and lead to the linear reduction of hysteresis energy. Besides, the cyclic hardening coefficient K’ and cyclic hardening index n’ of HSS would also decrease linearly with corrosion degree. Based on these experimental results, a new hysteresis constitutive model for corroded HSS steel was proposed, and its validity was verified.

scholarly journals On the Development of Material Constitutive Model for 45CrNiMoVA Ultra-High-Strength Steel

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 374 ◽  
Author(s):  
Xin Hu ◽  
Lijing Xie ◽  
Feinong Gao ◽  
Junfeng Xiang
Keyword(s):  
Constitutive Model ◽  
Strain Rate ◽  
High Strength Steel ◽  
Split Hopkinson Pressure Bar ◽  
High Strength ◽  
Model Parameters ◽  
Hopkinson Pressure Bar ◽  
Simulation Accuracy ◽  
Ultra High Strength Steel ◽  
Split Hopkinson

For the implementation of simulations for large plastic deformation processes such as cutting and impact, the development of the constitutive models for describing accurately the dynamic plasticity and damage behaviors of materials plays a crucial role in the improvement of simulation accuracy. This paper focuses on the dynamic behaviors of 45CrNiMoVA ultra-high-strength torsion bar steel. According to investigation of the Split-Hopkinson pressure bar (SHPB) and Split-Hopkinson tensile bar (SHTB) tests at different strain rate and different temperatures, 45CrNiMoVA ultra-high-strength steel is characterized by strain hardening, strain-rate hardening and thermal softening effects. Based on the analysis on the mechanism of the experimental results and the limitation of classic Johnson-Cook (J-C) constitutive model, a modified J-C model by considering the phase transition at high temperature is established. The multi-objective optimization fitting method was used for fitting model parameters. Compared with the classic J-C constitutive model, the fitting accuracy of the modified J-C model significantly improved. In addition, finite element simulations for SHPB and SHTB based on the modified J-C model are conducted. The SHPB stress-strain curves and the fracture morphology of SHTB samples from simulations are in good agreement with those from tests.

scholarly journals Constitutive Model and Flow Behavior of B1500HS High-Strength Steel During the Hot Deformation Process

Metals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 64 ◽  
Author(s):  
Li ◽  
Duan ◽  
Yao ◽  
Guan ◽  
Yang
Keyword(s):  
Flow Stress ◽  
Constitutive Model ◽  
Hot Deformation ◽  
High Strength Steel ◽  
Deformation Behavior ◽  
Flow Behavior ◽  
Constitutive Models ◽  
High Strength ◽  
Stress Strain ◽  
Comparison Results

Hot compression tests were carried out on a Gleeble-3800 thermal mechanical simulator in the temperature range from 700 to 900 °C and strain rate range from 0.005 to 10 s−1 to investigate the hot deformation behavior of B1500HS high-strength steel. Softening mechanisms of B1500HS high-strength steel under different deformation conditions were analyzed according to the characteristics of flow stress–strain curves. By analyzing and processing the experimental data, the values of steady flow stress, saturated stress, dynamic recovery (DRV) softening coefficient, and other factors were solved and these parameters were expressed as functions of Zener–Hollomon factors. Based on the dislocation density theory and the kinetic model of dynamic recrystallization (DRX), constitutive models corresponding to different softening mechanisms were established. The flow stress–strain curves of B1500HS predicted by a constitutive model are in good agreement with the experimental results and the correlation coefficient is . The comparison results indicate that the constitutive models can accurately reflect the deformation behavior of B1500HS high-strength steel under different conditions.

Study on the Dynamic Mechanical Property of High Strength Steel 18NiC250

2014 ◽  
Vol 644-650 ◽  
pp. 4763-4765
Author(s):  
Xiao Jun Shao ◽  
Peng Ke Liu ◽  
Zhi Yin Zeng ◽  
Wei Guo Guo
Keyword(s):  
Mechanical Property ◽  
Constitutive Model ◽  
Strain Rate ◽  
High Strength Steel ◽  
High Strength ◽  
Dynamic Mechanical Property ◽  
Hopkinson Pressure Bar ◽  
Dynamic Mechanical ◽  
Pressure Bar

In this paper, dynamic mechanical property tests under different tempreture and strain rate of high strength steel 18NiC250 are conducted by means of Hopkinson pressure bar technique. The results of tests show 18NiC250 steel is not only very sensitive on strain rate, but also sensitive to temperature. The rate relative constitutive model of this steel is obtained and well predicts dynamic mechanical property after yielded.

FEM on Constitutive Equation of High Strength Stress Steel GCr15

2012 ◽  
Vol 500 ◽  
pp. 569-573
Author(s):  
Xian Li Liu ◽  
Cai Xu Yue ◽  
Ming Ming Yu ◽  
Jia Yi Zhang ◽  
Ming Yang Wu
Keyword(s):  
Constitutive Equation ◽  
Constitutive Model ◽  
High Strength Steel ◽  
High Speed ◽  
Physical Property ◽  
High Strength ◽  
Model Parameters ◽  
Workpiece Material ◽  
High Speed Cutting ◽  
Influence Of Temperature On

Accuracy of cutting simulation model mostly depends on whether its material constitutive equation describes workpiece physical property under cutting state. It is necessary to research on the constitutive properties of cutting material in the high strain state of temperature. In this paper high strength steel GCr15 is used as a research object under the high speed cutting state. By FEM Johnson-cook constitutive model in Hopkinson Experiment is simulated, and the sensitivity of constant on constitutive model is also analyzed. Also influence of temperature on workpiece material stress and strain is revealed. The result provides reference for Johnson-cook model parameters of high strength steel GCr15, and it provides theory basis of material properties analysis in cutting state as well.

Research on Flow Behavior of Advanced High Strength Steel at Elevated Temperature

2013 ◽  
Vol 749 ◽  
pp. 498-503
Author(s):  
Cheng Xi Lei ◽  
Jun Jia Cui ◽  
Zhong Wen Xing ◽  
Hao Zhao
Keyword(s):  
Strain Rate ◽  
Linear Equation ◽  
High Strength Steel ◽  
Elevated Temperatures ◽  
Flow Behavior ◽  
Peak Stress ◽  
High Strength ◽  
Test Machine ◽  
Advanced High Strength Steel ◽  
Stress Strain

Tensile experiments were carried out on advanced high strength steel (AHSS) by the test machine Gleeble3500, under the temperature ranging from 650 to 850 and the strain rate of 0.1/s~5/s, and the corresponding stress-strain curves were obtained. The peak stress level decreases with the increasing of deformation temperature or the decreasing of strain rate, which can be represented by a ZenerHollomon parameter in a linear equation. A revised model describing the relationships between the peak stress, strain rate and temperature of advanced high strength steel at elevated temperatures was proposed by compensation of strain and strain rate. The comparison of the predicted and experimental results of stressstrain curve can prove the good predictive power of the model, the Adj. R-Square between the peak stress and the linear equation was reached to 0.97.

scholarly journals Effect of Selected Cooling and Deformation Parameters on the Structure and Properties of AISI 4340 Steel

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5585
Author(s):  
Maros Eckert ◽  
Michal Krbata ◽  
Igor Barenyi ◽  
Jozef Majerik ◽  
Andrej Dubec ◽  
...  
Keyword(s):  
High Strength Steel ◽  
True Strain ◽  
Peak Stress ◽  
High Strength ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Cooling Rates ◽  
Aisi 4340 Steel ◽  
4340 Steel ◽  
Aisi 4340

The paper is focused on investigation of the high-strength AISI 4340 steel at various temperature and deformation conditions. The article is divided into two specific analyses. The first is to examine the dilatation behavior of the steel at eight different cooling rates, namely, 100, 10, 5, 1, 0.5, 0.1, 0.05 and 0.01 °C·s−1. The mapping of the phase transformations due to varying cooling rates from the austenitizing temperature of 850 °C allows the construction of the CCT diagram for a given high-strength steel. These dilatation curves were also compared with the metallography of the selected samples for the proper construction of the CCT diagram. A further analysis of the high temperature deformation of high strength steel AISI 4340 was performed in the range of temperature 900–1200 °C, and the strain rate was in the range from 0.001 to 10 s−1 with maximum value of the true strain 0.9. Changes in the microstructure were observed using light optical microscopy (LOM). The effect of hot deformation temperature on true stress, peak stress and true strain was investigated. The hardness of all deformed samples, depending on the temperature, the deformation rate and the peak stress σp overall together related with hardness, has also been evaluated.

scholarly journals Experimental Research on Hysteretic Characteristics of Steel Plates Artificially Corroded by Neutral Salt Spray

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Shan-hua Xu ◽  
Guang-chong Qin ◽  
Zong-xing Zhang
Keyword(s):  
Constitutive Model ◽  
Salt Spray ◽  
Seismic Energy ◽  
Cyclic Hardening ◽  
Steel Plates ◽  
Neutral Salt ◽  
Loading Test ◽  
Skeleton Curve ◽  
Hysteretic Characteristics ◽  
First Time

This paper aims to study the hysteretic characteristics of the steel plates artificially corroded by neutral salt spray. Salt spray was applied to accelerate the corrosion on the steel plates; specimens of varying degrees of corrosion were obtained in this manner. And each specimen was subject to cyclic loading test to get the hysteretic curve. Then the experimental results were extensively discussed, focusing on strength and ductility, hysteretic energy, the skeleton curve, and unloading and loading curve. After that, the hysteretic constitutive model of corroded steel was established based on the first time loading criterion, unloading criterion, cycle skeleton criterion, and reloading curve criterion. The result of the experiment showed that, with the increase of the degree of corrosion, the mechanical properties and seismic energy dissipation performance of seismic energy of the steel decreased; the deterioration of ductility got aggravated. On the other hand, the skeleton curve and the Ramberg-Osgood model were well matched, and the coefficient of circular enhancement showed a decreasing trend; the variation of cyclic hardening exponent did not have an obvious pattern. Meanwhile, the hysteretic constitutive model of corroded steel and the results of the experiment were well matched.

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