Static Recrystallization Behavior of Non-Quenched and Tempered Steel 38MnSiVS

2020 ◽  
Vol 993 ◽  
pp. 482-491
Author(s):  
Yun Fei Cao ◽  
Wei Yu ◽  
Huan Yang ◽  
Wen Gao Chang ◽  
Zeng Qiang Man
Keyword(s):  
Strain Rate ◽  
Deformation Temperature ◽  
Static Recrystallization ◽  
Volume Fraction ◽  
Test Machine ◽  
Recrystallization Behavior ◽  
Interval Time ◽  
Static Softening ◽  
Quenched And Tempered Steel ◽  
Tempered Steel

Refinement and uniform austenite grains are essential to obtain excellent and homogenous properties for non-quenched and tempered steel, which is mainly affected by static recrystallization of the rolling process. Using the Gleeble-3500 thermal simulation test machine, 20% compression test was carried out for two passes at 850~1050 °C (interval of 50 °C) and different pass interval time conditions to study the static softening and recrystallization behavior of 38MnSiVS non-quenched and tempered steel during deformation process. The effects of strain rate, deformation temperature and interval time on static softening rate and austenite recrystallization fraction were analyzed. The results showed that the increase of deformation temperature and the increase of pass interval time had more significant impact on the static recrystallization volume fraction of 38MnSiVS steel, while the influence of strain rate was relatively smaller. When the deformation temperature was 950 °C or higher, the non-conditioning steel 38MnSiVS could undergo complete recrystallization, and partial recrystallization occurred in the temperature range of 850-950 °C. A static recrystallization volume fraction model of non-regulatory steel 38MnSiVS was established. The static recrystallization activation energy was 296.7 kJ·mol-1, and the static recrystallization volume fraction model had a relative error of 2%.

scholarly journals Modeling and Simulation of the Static Recrystallization of 5754 Aluminium Alloy by Cellular Automaton

Metals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 585 ◽  
Author(s):  
Changqing Huang ◽  
Xiaodong Jia ◽  
Zhiwu Zhang
Keyword(s):  
Grain Size ◽  
Strain Rate ◽  
Aluminium Alloy ◽  
Delay Time ◽  
Deformation Temperature ◽  
Static Recrystallization ◽  
Double Pass ◽  
Deformation Parameters ◽  
Static Softening ◽  
The Mean

To study the factors that affect the mechanical properties of materials, double-pass hot compression tests were performed under different deformation parameters using a Gleeble-3500 thermo-simulation machine. The static softening behavior of 5754 aluminium alloy during testing was analyzed by the 0.2% offset-stress method. The results show that the static softening fraction was greatly influenced by deformation parameters and rapidly increased with increasing delay time, strain rate and deformation temperature. In addition, a mesoscopic cellular automaton (CA) model was employed to simulate the microstructural evolution of the static recrystallization (SRX) during the double-pass hot compression test of the 5754 aluminium alloy. The results show that the SRX nuclei first formed along the grain boundaries, where the energy was sufficient, and deformation parameters had a significant influence on the SRX of the 5754 aluminium alloy. The recrystallized volume fraction increased with increasing temperature, strain rate, and delay time among deformation stages. The mean recrystallized grain size increased with increasing deformation temperature and delay time. However, the mean grain size was slightly reduced with an increase in the strain rate from 0.1 s−1 to 1 s−1 at constant temperature and delay time.

Hot Compression Deformation Behavior of Spray-Formed AlSn20Cu Alloy

2021 ◽  
Vol 1035 ◽  
pp. 189-197
Author(s):  
Bao Ying Li ◽  
Bao Hong Zhu
Keyword(s):  
Constitutive Equation ◽  
Strain Rate ◽  
Deformation Behavior ◽  
Deformation Temperature ◽  
Phase Distribution ◽  
True Stress ◽  
Hot Compression ◽  
Test Machine ◽  
Hot Compression Deformation ◽  
Compression Deformation

The hot deformation behavior of spray-formed AlSn20Cu alloy during hot compression deformation was studied, and the constitutive equation of AlSn20Cu alloy was established. The samples of spray-formed AlSn20Cu alloy were compressed on Gleeble-3500 thermal simulation test machine. The error of the true stress caused by adiabatic heating effect in the experiment was corrected. The constitutive equation of spray-formed AlSn20Cu alloy could be represented by Zener-Hollomon parameter in a hyperbolic sine function. The results showed that the deformation temperatures and strain rates had a notable effect on the true stress of the alloy. At the identical deformation temperature, the true stress increased with the increase of strain rate. When the strain rate was constant, the stress decreased with the increase of deformation temperature. After hot compression deformation, the tin phase was elongated along the direction perpendicular to the compression axis with short strips and blocks. With the increase of deformation temperature and the decrease of strain rate, Sn phase distribution became more homogeneous.

The Superplastic Properties and Microstructures Evolution of High Nb Ti3Al Based Alloy

2016 ◽  
Vol 838-839 ◽  
pp. 568-573 ◽  
Author(s):  
Xiu Quan Han ◽  
Ming Jie Fu
Keyword(s):  
Strain Rate ◽  
Work Hardening ◽  
Deformation Temperature ◽  
Volume Fraction ◽  
Alloy Sheet ◽  
Deformation Condition ◽  
Maximum Elongation ◽  
Β Phase ◽  
Superplastic Properties ◽  
Softening Stage

The superplasticity of high Nb Ti3Al based alloy - Ti-23Al-17Nb (at.%) alloy sheet under the conditions of 940~1000°C and 5.5×10-5s-1~1.7×10-3s-1are studied. The results show the elongation changes as a parabola with the deformation temperature increasing, and the maximum elongation obtained at 960°C and 5.5x10-5s-1 is 1447.5%. Work hardening stage increases much more than softening stage when strain rate is decreased due to the increasing of element Nb. Compared with primary microstructure, the lath-like α2 grains gradually disappeared, the α2 grains became more equiaxed, and the content and size of α2 grains are decreasing with increasing of deformation temperature. The volume fraction ratio of α2 and β phase at the optimum deformation condition is 50:50%. The cavities mechanism at the fracture tip was discussed; it can be defined that the cavities could be avoided when deformation temperature is higher than 940°C.

Static Softening Behavior of Low Carbon High Niobium Microalloyed Steel

2020 ◽  
Vol 990 ◽  
pp. 36-43
Author(s):  
Dian Xiu Xia ◽  
Heng Ke Du ◽  
Xin En Zhang ◽  
Xiu Cheng Li ◽  
Ying Chao Pei
Keyword(s):  
Deformation Temperature ◽  
Static Recrystallization ◽  
Microalloyed Steel ◽  
Testing Machine ◽  
Low Carbon ◽  
High Deformation ◽  
Softening Behavior ◽  
Test Steel ◽  
Static Softening ◽  
Niobium Microalloyed Steel

The MMS-200 thermal simulation testing machine was used to study the static softening behavior of low carbon high niobium microalloyed steel. The effect of niobium to the static recrystallization softening behavior of the microalloy steel had been analyzed by establishing the kinetics model of static recrystallization and the micro-morphology of precipitates. The results indicated that: the static softening behavior of the tested steel significantly influenced by the deformation temperature and the interval pass time of the rolling processing. At relatively high deformation temperature and long interval pass time, the ratio of static softening was increased. Then the deformation temperature was lower to 950°C, and the static softening behavior of the test steel was ceased. But when the deformation temperature was higher than 1000°C, the static softening behavior of the test steel completely occurred. The activation energy of the test steel was 325·mol-1 by the established model calculated.

Effect of Hot Deformation Parameters on Flow Behavior and Microstructure of Ti-6Al-4V-0.2O Alloy

2017 ◽  
Vol 898 ◽  
pp. 137-143
Author(s):  
Lin Xiang ◽  
Bin Tang ◽  
Hong Chao Kou ◽  
Jie Shao ◽  
Jin Shan Li
Keyword(s):  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Temperature ◽  
Dynamic Recovery ◽  
Volume Fraction ◽  
Flow Behavior ◽  
Strain Rates ◽  
Compression Tests ◽  
Height Reduction ◽  
Deformation Parameters

Isothermal compression tests were conducted to investigate the effect of hot deformation parameters on flow behavior and microstructure of Ti-6Al-4V-0.2O alloy. The experimental results show that the strain rate and height reduction have little effect on the volume fraction of primary α at a deformation temperature of 860 ̊C. At a deformation temperature of 940 ̊C, the volume fraction of primary α at a high strain rate (10s-1) is about 10% less than that at low strain rates (0.01s-1~1s-1). It may be one of the reasons for the significantly discontinuous yielding phenomenon. Another reason is that the dislocation density decreased suddenly due to the dynamic recovery. With the increasing strain rate and the decreasing deformation temperature, the volume fraction of irregular secondary α increases and lamellar secondary α decreases. And with height reduction increasing, the irregular secondary α increases firstly and then tends to be steady because of dynamic recovery and recrystallization.

Dynamic Recrystallization Behavior of Mg-Gd-Y-Zr Alloy during Hot Compression

2016 ◽  
Vol 849 ◽  
pp. 181-185 ◽  
Author(s):  
Shi Lun Yu ◽  
Yong Hao Gao ◽  
Chu Ming Liu ◽  
Hong Chao Xiao
Keyword(s):  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Volume Fraction ◽  
Peak Stress ◽  
Critical Conditions ◽  
Recrystallization Behavior ◽  
Compression Tests ◽  
Dynamic Recrystallization Behavior ◽  
Increasing Temperature ◽  
The Cost

Dynamic recrystallization behavior of Mg-8.0Gd-3.0Y-0.5Zr (wt.%) alloy and the critical conditions corresponding to the onset of dynamic recrystallization were investigated using uniaxial compression tests conducted at temperatures ranging from 350 °C to 500 °C and strain rates ranging from 0.001 s-1 to 1 s-1. Results show that increasing temperature and/or decreasing strain rate can enhance the process of dynamic recrystallization of Mg-8.0Gd-3.0Y-0.5Zr alloy and lower the peak stress and corresponding strain. However, decreasing temperature and/or increasing strain rate can promote the occurrence of twin dynamic recrystallization (TDRX) within the original grains at the cost of reducing the total volume fraction of dynamically recrystallized grains in the microstructure. Besides, the critical stress and strain corresponding to the onset of dynamic recrystallization of Mg-8.0Gd-3.0Y-0.5Zr at 400 °C and 0.1 s-1 are 173MPa and 0.13, respectively.

Prediction Model for Microstructure and Properties of Medium Carbon Non-Quenched and Tempered Steel Bar

2020 ◽  
Vol 993 ◽  
pp. 526-533
Author(s):  
Shi Kang Lu ◽  
Yu Lai Chen ◽  
Wei Yu
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Prediction Model ◽  
Prediction Models ◽  
Volume Fraction ◽  
Second Phase ◽  
Medium Carbon ◽  
Steel Bar ◽  
Quenched And Tempered Steel ◽  
Tempered Steel

In this study, the 38MnSiVS medium carbon non-quenched and tempered steel bar was investigated by optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM) and quantitative metallography. The microstructures were mainly composed of ferrite and pearlite. The phase transition-microstructure prediction models were established to calculate ferrite volume fraction fα, ferrite grain size dα and pearlite interlamellar spacing So. The volume fraction of the second phase V (C, N) was calculated by thermodynamics. The morphology of the second phase V (C, N) was observed by TEM, and the distribution of particle size of the second phase was determined. And the mechanical properties were measured. Considering the microstructural parameters (fα,dα and So), the modified coefficient of solid solution elements, and the effect of precipitates, combining with some reference models, prediction model of mechanical properties including yield strength, tensile strength and impact toughness were finally established.

Experimental investigation on static recrystallization behavior of a low carbon Nb–V–Ti microalloyed steel

2021 ◽  
Vol 118 (2) ◽  
pp. 202
Author(s):  
Fei Li ◽  
Liwen Zhang ◽  
Chi Zhang ◽  
Qing Yang ◽  
Chaoqun Li ◽  
...  
Keyword(s):  
Grain Size ◽  
Strain Rate ◽  
Deformation Temperature ◽  
Static Recrystallization ◽  
Microalloyed Steel ◽  
Pipeline Steel ◽  
Low Carbon ◽  
Compression Tests ◽  
X70 Pipeline Steel ◽  
Deformation Parameters

The static recrystallization (SRX) behavior of a low carbon Nb–V–Ti microalloyed steel X70 was investigated by two-pass hot compression tests. The compression tests were carried out at deformation temperatures of 1000–1150 °C, strain rates of 0.01–5 s−1, pre-strains of 0.1–0.2 and interval times of 1–50 s. The effects of deformation parameters on SRX behavior were analyzed. The experimental results showed that deformation temperature, pre-strain and strain rate had significant influence on SRX fraction, while initial grain size had a smaller impact. The effects of deformation parameters on SRX microstructure were discussed, and the microstructure evolution process was analyzed. Higher deformation temperature, strain rate and pre-strain lead to larger SRX fraction. The kinetics and recrystallized grain size models for SRX of X70 pipeline steel were developed. Comparison between the predicted results and the experimental ones indicated that the established equations could give a reasonable description for SRX behavior of X70 pipeline steel.

scholarly journals The Microstructure Evolution of Thermal Deformation of Continuous Extrusion Copper Bus Bar

2018 ◽  
Vol 228 ◽  
pp. 04006
Author(s):  
Jing Lu ◽  
Gaosheng Fu ◽  
Zhimeng Ren ◽  
Jie Liu ◽  
Huan Hao
Keyword(s):  
Grain Size ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Deformation Temperature ◽  
Thermal Deformation ◽  
Raw Material ◽  
Test Machine ◽  
Deformation Microstructure ◽  
Average Grain Size ◽  
Continuous Extrusion

The thermal deformation microstructure of continuous extrusion copper bus bar was observed and analyzed in the temperature range from 200°C to 700°C and at strain rate from 0.01s-1 to 10.0s-1 and at deformation amount from30% to 90% on Gleeble1500 test machine. The experiment results show that the higher the temperature, the lower the strain rate, the more dynamic recrystallization occurred. At the same strain rate, the copper bus bar changes from raw material of as-cast organization to recrystallization grain gradually as the deformation temperature and deformation degree increase, and the recrystallization grain size grows older with the rise of temperature. At the same deformation temperature, the temperature of recrystallization nucleation decreases while the strain rate increases. At low strain rate (0.01~1.0s-1), the dynamic recrystallization occurred at 500°C. While at high strain rate (10.0s-1), the recrystallization nucleation is advanced and it is already completed at 500°C. The Z parameters can be used to express the effect of deformation temperature and strain rate on the average grain size D, and the prediction model of the thermal deformation microstructure is obtained as follows: lnD=4.822-0.018lnZ

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