Application to Body Parts of High-Strength Steel Sheet Containing Large Volume Fraction of Retained Austenite

1998 ◽  
Author(s):  
Yoshifumi Ojima ◽  
Yukiyasu Shiroi ◽  
Yoichi Taniguchi ◽  
Kazuhiko Kato
Keyword(s):  
Large Volume ◽  
High Strength Steel ◽  
Retained Austenite ◽  
Steel Sheet ◽  
Volume Fraction ◽  
High Strength ◽  
Body Parts ◽  
Large Volume Fraction

Optimization of the Product of Strength and Plasticity of Hot-Stamped WHT1300HF High Strength Steel

2013 ◽  
Vol 798-799 ◽  
pp. 280-285
Author(s):  
Kai Liu ◽  
Bo Chi ◽  
Zeng Min Shi ◽  
Ji Bin Liu ◽  
Li Jian
Keyword(s):  
Tensile Strength ◽  
High Strength Steel ◽  
Retained Austenite ◽  
Room Temperature ◽  
Volume Fraction ◽  
High Strength ◽  
Carbide Precipitation ◽  
Maximum Value ◽  
Untransformed Austenite ◽  
Strength And Plasticity

The quenching and partitioning (Q&P) process was performed on high strength steel WHT1300HF at 250-350 °C for 30 to 90 s, respectively, for the improvement of its product of strength and plasticity (PSP). ε-carbide precipitation was observed in all the specimens partitioned at each temperature for different periods of time due to inadequate amount of Si in the composition of WHT1300HF steel. The volume fraction of retained austenite at room temperature in the partitioned specimens is extremely low due to the lack of carbon enrichment in untransformed austenite at the partitioning temperature as a result of the carbide precipitation. The decrease of tensile strength and increase of elongation are caused by the partitioning treatment, a maximum value of the PSP (17.6 GPa%) is achieved by partitioning at 300 °C for 60 s.

Retained austenite-induced fire-resistance of a 690 MPa high strength steel

2021 ◽  
Vol 291 ◽  
pp. 129448
Author(s):  
L.J. Wei ◽  
X.M. Ji ◽  
Y.S. Yu ◽  
R.D.K. Misra ◽  
P.C. Liu ◽  
...  
Keyword(s):  
Fire Resistance ◽  
High Strength Steel ◽  
Retained Austenite ◽  
High Strength

scholarly journals Carbon Redistribution and Microstructural Evolution Study during Two-Stage Quenching and Partitioning Process of High-Strength Steels by Modeling

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2302 ◽  
Author(s):  
Yilin Wang ◽  
Huicheng Geng ◽  
Bin Zhu ◽  
Zijian Wang ◽  
Yisheng Zhang
Keyword(s):  
Retained Austenite ◽  
Volume Fraction ◽  
High Strength Steels ◽  
High Strength ◽  
Simulation Method ◽  
Low Carbon ◽  
Two Stage ◽  
Quenching And Partitioning ◽  
Carbon Redistribution ◽  
Carbon Martensite

The application of the quenching and partitioning (Q-P) process on advanced high-strength steels improves part ductility significantly with little decrease in strength. Moreover, the mechanical properties of high-strength steels can be further enhanced by the stepping-quenching-partitioning (S-Q-P) process. In this study, a two-stage quenching and partitioning (two-stage Q-P) process originating from the S-Q-P process of an advanced high-strength steel 30CrMnSi2Nb was analyzed by the simulation method, which consisted of two quenching processes and two partitioning processes. The carbon redistribution, interface migration, and phase transition during the two-stage Q-P process were investigated with different temperatures and partitioning times. The final microstructure of the material formed after the two-stage Q-P process was studied, as well as the volume fraction of the retained austenite. The simulation results indicate that a special microstructure can be obtained by appropriate parameters of the two-stage Q-P process. A mixed microstructure, characterized by alternating distribution of low carbon martensite laths, small-sized low-carbon martensite plates, retained austenite and high-carbon martensite plates, can be obtained. In addition, a peak value of the volume fraction of the stable retained austenite after the final quenching is obtained with proper partitioning time.

Modeling of Anisotropic Plastic Behavior of Advanced High Strength Steel Sheet TRIP 780

2011 ◽  
Vol 410 ◽  
pp. 232-235 ◽  
Author(s):  
Sansot Panich ◽  
Vitoon Uthaisangsuk ◽  
Surasak Suranuntchai ◽  
Suwat Jirathearanat
Keyword(s):  
High Strength Steel ◽  
Steel Sheet ◽  
Plastic Anisotropy ◽  
High Strength ◽  
Uniaxial Tensile ◽  
Plastic Behavior ◽  
Biaxial Test ◽  
Advanced High Strength Steel ◽  
Yield Criteria ◽  
Anisotropic Plastic

Anisotropic plastic behavior of advanced high strength steel sheet of grade TRIP780 (Transformation Induced Plasticity) was investigated using three different yield functions, namely, the von Mises’s isotropic, Hill’s anisotropic (Hill’48), and Barlat’s anisotropic (Yld2000-2d) criterion. Uniaxial tensile and balanced biaxial test were conducted for the examined steel in order to characterize flow behavior and plastic anisotropy for different stress states. Especially, disk compression test was performed for obtaining balanced r-value. All these data were used to determine the anisotropic coefficients. As a result, yield stresses and r-values for different directions were calculated according to these yield criteria. The results were compared with experimental data. To verify the modelling accuracy, tensile tests of various notched samples were carried out and stress-strain distributions in the critical area were characterized. By this manner, the effect of stress triaxiality due to different notched shapes on the strain localization calculated by the investigated yield criteria could be studied.

Flipping Carbon Nanotubes to Continuously Produce Strong, Transparent, Multifunctional Sheets

2005 ◽  
Author(s):  
Mei Zhang ◽  
Shaoli Fang ◽  
Anvar A. Zakhidov ◽  
Sergey B. Lee ◽  
Ali E. Aliev ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
High Strength Steel ◽  
Steel Sheet ◽  
High Strength ◽  
Nanotube Arrays

We demonstrate carbon nanotube assembly by cooperatively rotating carbon nanotubes in vertically-oriented nanotube arrays (forests) and make 5-centimeter-wide, meter-long transparent sheets. These self-supporting nanotube sheets are initially formed as a highly anisotropic electronically conducting aerogel that can be densified into strong sheets that are as thin as 50 nanometers. The measured gravimetric strength of orthogonally oriented sheet arrays exceeds that of high strength steel sheet.

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