A study on the multi-phase transformation kinetics of ultra-high-strength steel and application in thermal-mechanical-phase coupling simulation of hot stamping process

2016 ◽  
Vol 673 ◽  
pp. 24-38 ◽  
Author(s):  
Guo-zheng Quan ◽  
Zong-yang Zhan ◽  
Le Zhang ◽  
Dong-sen Wu ◽  
Gui-chang Luo ◽  
...  
Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1119 ◽  
Author(s):  
Pengyun Zhang ◽  
Le Zhu ◽  
Chenyang Xi ◽  
Junting Luo

Based on the Kirkaldy-Venugopalan model, a theoretical model for the phase transformation of USIBOR® 1500 high strength steel was established, and a graph of the phase transformation kinetics of ferrite, pearlite, and bainite were plotted using the software MATLAB. Meanwhile, with the use of the software DYNAFORM, the thermal stamping process of an automobile collision avoidance beam was simulated. The phase transformation law of USIBOR® 1500 high-strength steel during hot stamping was studied through a simulation of the phase transformation during the pressure holding quenching process. In combination with the continuous cooling transformation (CCT) curve, the cooling rate of quenching must be greater than 27 °C/s to ensure maximum martensite content in the final parts, and the final martensite content increases as the initial temperature of the sheet rises.


Author(s):  
Jong-Kyu Park ◽  
Yang-Su Kim ◽  
Chang Hee Suh ◽  
Young-Suk Kim

Recently, tubular-type coupled torsion beam axle, which is a component of the automotive rear suspension systems, has been developed by using ultra-high strength steel. It is manufactured by hot stamping process to enhance the strength and reduce springback. The hot stamping process is classified as a direct method and an indirect method according to forming sequence and quenching method, so-called die quenching or water quenching. Each of these methods has limitations in the aspect of dimensional accuracy and strength. Hybrid quenching is a new quenching method which sprays water to the tube directly in addition to die quenching. In this study, direct hot stamping with hybrid quenching was applied to produce an automotive tubular coupled torsion beam axle of ultra-high strength steel. This study proposes a simulation method of hybrid quenching for tubular beam and the hybrid quenching method was evaluated experimentally. Finally, the proposed hybrid quenching method has been found very effective in reducing the cooling time and thermal deformation.


Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 833 ◽  
Author(s):  
Tang ◽  
Gu ◽  
Jia ◽  
Li ◽  
Zhu ◽  
...  

Aiming at the need for lightweight requirements of the electric bus components, combined with the performance advantages of the hot stamping ultra-high strength steel, a new type of seat bracket structure is proposed. The new structure was analyzed by finite element method and the variable density topology optimization results. Subsequently, the new seat bracket was manufactured by the indirect hot stamping process. The results showed that the new type of seat bracket can reduce the weight by 17.04% after topology optimization, which achieved the goal of lightweight design of the structure. After indirect hot stamping, the bottom of the seat bracket microstructures were mainly martensite and the ultimate tensile strength was about 1560 MPa, the microhardness was equally distributed at about 513.5 HV. Finally, according to the stiffness check test, the seat bracket satisfied the user requirements.


2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Wenhua Wu ◽  
Ping Hu ◽  
Guozhe Shen

The thermomechanical-phase transformation coupled relationship of high-strength steel has important significance in forming the mechanism and numerical simulation of hot stamping. In this study a new numerical simulation module of hot stamping is proposed, which considers thermomechanical-transformation multifield coupled nonlinear and large deformation analysis. In terms of the general shell finite element and 3D tetrahedral finite element analysis methods related to temperature, a coupled heat transmission model for contact interfaces between blank and tools is proposed. Meanwhile, during the hot stamping process, the phase transformation latent heat is introduced into the analysis of temperature field. Next the thermomechanical-transformation coupled constitutive models of the hot stamping are considered. Static explicit finite element formulae are adopted and implemented to perform the full numerical simulations of the hot stamping process. The hot stamping process of typical U-shaped and B-pillar steel is simulated using the KMAS software, and a strong agreement comparison between temperature, equivalent stress, and fraction of martensite simulation and experimental results indicates the validity and efficiency of the hot stamping multifield coupled constitutive models and numerical simulation software KMAS. The temperature simulated results also provide the basic guide for the optimization designs of cooling channels in tools.


2021 ◽  
Vol 64 ◽  
pp. 916-926
Author(s):  
Ali Talebi-Anaraki ◽  
Tomoyoshi Maeno ◽  
Ryohei Ikeda ◽  
Kazui Morishita ◽  
Ken-ichiro Mori

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