Modeling of the Dynamic Recrystallization of Ti Microalloyed High‐Strength Steel

2021 ◽  
pp. 2100461
Author(s):  
Xiaoguang Zhou ◽  
Xixiang Wang ◽  
Xin Li ◽  
Zhenyu Liu
Keyword(s):  
Dynamic Recrystallization ◽  
High Strength Steel ◽  
High Strength

scholarly journals Interactions Between Dynamic Softening and Strengthening Mechanisms During Hot Forging of a High-Strength Steel

2021 ◽  
Vol 7 ◽  
Author(s):  
Makarim Khan ◽  
Davood Shahriari ◽  
Mohammad Jahazi ◽  
Jean-Benoit Morin
Keyword(s):  
Electron Microscopy ◽  
Dynamic Recrystallization ◽  
High Strength Steel ◽  
True Strain ◽  
Hot Forging ◽  
High Strength ◽  
Actual Process ◽  
Dynamic Precipitation ◽  
Die Forging ◽  
Open Die Forging

Open-die forging is a critical step in the manufacture of large numbers of components used in the transportation and energy industries. Dynamic recrystallization, dynamic transformation, and dynamic precipitation take place during the hot deformation process and significantly affect microstructure conditioning, which ultimately influences the service properties of the component. In the present work, using a Gleeble 3800 thermomechanical simulator, the open-die forging of a large-size ingot made of a modified AISI 6140 medium carbon high-strength steel is investigated. Deformation temperatures ranging from 950°C to 1,250°C and strain rates ranging from 0.01 to 1 s−1, representative of the actual process, are considered in the analysis. The generated true stress–true strain curves are used as a basis for the development of a constitutive model predicting the occurrence of softening and strengthening phenomena as a function of thermomechanical conditions. The corresponding activation energy is determined to be about 374 kJ mol−1 and is compared against the values reported in the literature for other high-strength steels. Dynamic recrystallization kinetics is studied using the t50 model, and the influence of temperature and strain rate is quantified and discussed. The interaction between dynamic precipitation and dynamic recrystallization is discussed, and the deformation conditions under which such interactions occur are determined. The thermomechanical results are validated by microstructure examination, including laser confocal microscopy, field emission scanning electron microscopy, transmission electron microscopy, and energy-dispersive spectroscopy. The present study focuses on reproducing the deformation cycle applied during the open-die forging process of a vanadium-containing high-strength steel used in the industry with special attention to the interaction between dynamic recrystallization and precipitation processes.

scholarly journals Softening Characterization of 300M High-Strength Steel during Post-Dynamic Recrystallization

Metals ◽  
2018 ◽  
Vol 8 (5) ◽  
pp. 340 ◽  
Author(s):  
Rong Zeng ◽  
Liang Huang ◽  
Hongliang Su ◽  
Huijuan Ma ◽  
Yangfei Ma ◽  
...  
Keyword(s):  
Dynamic Recrystallization ◽  
High Strength Steel ◽  
High Strength

scholarly journals Dynamic Behaviors and Microstructure Evolution of Iron–Nickel Based Ultra-High Strength Steel by SHPB Testing

Metals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 62 ◽  
Author(s):  
Hongge Fu ◽  
Xibin Wang ◽  
Lijing Xie ◽  
Xin Hu ◽  
Usama Umer ◽  
...  
Keyword(s):  
Dynamic Recrystallization ◽  
Strain Rate ◽  
High Strength Steel ◽  
High Strain ◽  
High Strength ◽  
Compression Tests ◽  
Static Compression ◽  
Dynamic Behaviors ◽  
Ultra High Strength Steel ◽  
Iron Nickel

Iron–nickel based ultra-high strength steel (wt. 18~20% Ni) is characterized by its high strength and low thermal conductivity, and is normally used to make key components by forming and machining processes. The optimization of these processes is based on a deep understanding of the mechanical and dynamic behaviors under high strain, high strain rate, and high temperature. In this paper, the relationship of stress to strain, strain rate, and temperature is systematically investigated by the dynamic compression tests combined with quasi-static compression tests, and the hardening and softening is associated with the transformation in microstructures. According to the analysis, dynamic recrystallization around 600 °C is assumed to be one important influencing factor, hence hot deformation equations are established and the critical strain for dynamic recrystallization and the volume fraction of the dynamic recrystallized grains are defined.

scholarly journals CONSTITUTIVE MODELING OF DYNAMIC RECRYSTALLIZATION AND PRECIPITATION BEHAVIOR OF Nb AND Ti OF Q1030 HIGH STRENGTH STEEL

2020 ◽  
Vol 1 (1) ◽  
pp. 01-05
Author(s):  
J.J. Wang ◽  
Y.L. Kang ◽  
Y.L. Liu ◽  
H Yu
Keyword(s):  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Hot Deformation ◽  
High Strength Steel ◽  
Critical Strain ◽  
High Strength ◽  
Second Phase ◽  
Peak Strain ◽  
Precipitation Behavior ◽  
Deformation Equation

The thermal deformation and precipitation behavior at 900-1100℃ and strain rate of 0.1-5s-1 were studied by Gleeble-3800 thermal simulator of Q1030 high strength steel. The activation energy of hot deformation in austenite region was determined by regression method, and the hot deformation equation of the Q1030 high strength steel was established. The critical strain and peak strain of dynamic recrystallization were predicted accurately by fitting the inflection point with cubic polynomial of curve of Q1030 high strength steel, and relationship between critical strain and Z parameter was established. Finally, the precipitation behavior of Nb and Ti particles during low strain rate deformation was studied, the results show that the precipitated phases in steel are rectangular TiN, quadratic (Nb, Ti) (C, N) carbonitride, elliptical (Nb, Ti) C carbide and NbC. Thermodynamic calculation shows that the order of precipitation of the second phase in steel is TiN, TiC, NbC and NbN.

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