High Manganese Advanced High Strength TWIP Steel for Automotive Applications

2011 ◽  
Vol 1296 ◽  
Author(s):  
Bruno C. De Cooman
Keyword(s):  
Texture Evolution ◽  
High Strength ◽  
Ferromagnetic Transition ◽  
Automotive Applications ◽  
Present Contribution ◽  
Delayed Fracture ◽  
Passenger Safety ◽  
Fundamental Understanding ◽  
Twip Steels ◽  
State Of The Science

ABSTRACTHigh Mn TWinning-Induced Plasticity (TWIP) steels have mechanical properties which make them suitable for effective vehicle mass containment and an enhanced passenger safety in automotive applications. High Mn TWIP steels with additions of C and Al are fully austenitic at room temperature and have a stacking fault energy (SFE) within the narrow range of 20-30 mJ/m2 required for mechanical twin formation. The present contribution reviews the state-of-the-science on TWIP steels, and highlights those areas where there is still a lack of fundamental understanding of their properties, such as the effect of the anti-ferromagnetic transition, the influence of interstitial C, the twinning mechanism, the effect of slip and twinning on the crystallographic texture evolution and the delayed fracture phenomenon.

scholarly journals Influence of Nb Microaddition on Microstructure and Texture Evolution in a Fe-21Mn-1.3Al-1.5Si-0.5C TWIP Steel under Uniaxial Hot-Tensile Conditions

MRS Advances ◽  
2017 ◽  
Vol 2 (61) ◽  
pp. 3797-3803
Author(s):  
A.E. Salas-Reyes ◽  
I. Mejía ◽  
J.M. Cabrera
Keyword(s):  
Crystallographic Orientation ◽  
Twip Steel ◽  
Electron Backscatter Diffraction ◽  
Texture Evolution ◽  
Constant Strain Rate ◽  
High Strength Steels ◽  
High Strength ◽  
Orientation Distribution ◽  
Deformation State ◽  
Twip Steels

ABSTRACTAdvanced high-strength steels as Twinning Induced Plasticity (TWIP) steels have been developed using microalloying elements and subsequent thermo-mechanical processing techniques. Moreover, under hot-working conditions, these steels undergo significant microstructural changes as a result of preferred crystallographic orientation (texture) of grains. In order to evaluate this behavior, one non-microalloyed and other single Nb-microalloyed TWIP steels were melted in an induction furnace and cast into metal and sand molds. Samples with austenitic grain sizes between 400 and 2000 µm were deformed at 800 °C and strained at a constant strain rate of 10-3 s-1, and deformation state was examined by means of electron backscatter diffraction (EBSD) technique near to the fracture tip. It was found that non-microalloyed TWIP steel solidified in both metal and sand mold exhibits dynamically recrystallized grains. On the other hand, Nb microaddition has a strong influence in TWIP steel retarding the onset of recrystallization kinetics, showing low angle sub-structured grains. Furthermore, it was possible identifying the crystallographic orientation of grains using the inverse pole figures (IPF) and the orientation distribution function (ODF). Weak cube {001}<100> recrystallization and E{111}<110> γ-fiber deformation textures components were detected.

State-of-the-Science of High Manganese TWIP Steels for Automotive Applications

2009 ◽  
pp. 165-183 ◽  
Author(s):  
B. C. De Cooman ◽  
L. Chen ◽  
Han Soo Kim ◽  
Y. Estrin ◽  
S. K. Kim ◽  
...  
Keyword(s):  
Automotive Applications ◽  
High Manganese ◽  
Twip Steels ◽  
State Of The Science

Selection and use of coated advanced high-strength steels for automotive applications

2004 ◽  
Vol 101 (7-8) ◽  
pp. 551-558 ◽  
Author(s):  
R. Bode ◽  
M. Meurer ◽  
T. W. Schaumann ◽  
W. Warnecke
Keyword(s):  
High Strength Steels ◽  
High Strength ◽  
Automotive Applications ◽  
Advanced High Strength Steels

Constant-load delayed fracture test of atmospherically corroded high strength steels

2011 ◽  
Vol 257 (19) ◽  
pp. 8275-8281 ◽  
Author(s):  
Eiji Akiyama ◽  
Katsuhiro Matsukado ◽  
Songjie Li ◽  
Kaneaki Tsuzaki
Keyword(s):  
High Strength Steels ◽  
High Strength ◽  
Constant Load ◽  
Fracture Test ◽  
Delayed Fracture

scholarly journals Modeling of Forming Limit Bands for Strain-Based Failure-Analysis of Ultra-High-Strength Steels

Metals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 631 ◽  
Author(s):  
Hamid Bayat ◽  
Sayantan Sarkar ◽  
Bharath Anantharamaiah ◽  
Francesco Italiano ◽  
Aleksandar Bach ◽  
...  
Keyword(s):  
Material Properties ◽  
Driving Forces ◽  
Weight Ratio ◽  
High Strength Steels ◽  
High Strength ◽  
Forming Limit ◽  
Boron Steel ◽  
Passenger Safety ◽  
Ultra High Strength Steels ◽  
Increased Strength

Increased passenger safety and emission control are two of the main driving forces in the automotive industry for the development of light weight constructions. For increased strength to weight ratio, ultra-high-strength steels (UHSSs) are used in car body structures. Prediction of failure in such sheet metals is of high significance in the simulation of car crashes to avoid additional costs and fatalities. However, a disadvantage of this class of metals is a pronounced scatter in their material properties due to e.g., the manufacturing processes. In this work, a robust numerical model is developed in order to take the scatter into account in the prediction of the failure in manganese boron steel (22MnB5). To this end, the underlying material properties which determine the shapes of forming limit curves (FLCs) are obtained from experiments. A modified Marciniak–Kuczynski model is applied to determine the failure limits. By using a statistical approach, the material scatter is quantified in terms of two limiting hardening relations. Finally, the numerical solution obtained from simulations is verified experimentally. By generation of the so called forming limit bands (FLBs), the dispersion of limit strains is captured within the bounds of forming limits instead of a single FLC. In this way, the FLBs separate the whole region into safe, necking and failed zones.

Relationship between Microstructure and Mechanical Properties in Q&P-Steels

2016 ◽  
Vol 879 ◽  
pp. 1933-1938 ◽  
Author(s):  
Richard G. Thiessen ◽  
Georg Paul ◽  
Roland Sebald
Keyword(s):  
Mechanical Properties ◽  
Dual Phase Steel ◽  
High Strength Steels ◽  
High Strength ◽  
The Body ◽  
Advanced High Strength Steels ◽  
Passenger Safety ◽  
Back Scattering ◽  
Body In White ◽  
Expected Increase

Third-Generation advanced high strength steels are being developed with the goal of reducing the body-in-white weight while simultaneously increasing passenger safety. This requires not only the expected increase in strength and elongation, but also improved local formability. Optimizing elongation and formability were often contradictory goals in dual-phase steel developments. Recent results have shown that so-called "quench and partitioning" (Q&P) concepts can satisfy both requirements [1]. Many Q&P-concepts have been studied at thyssenkrupp Steel Europe. Thorough investigation of the microstructure has revealed relationships between features such as the amount, morphology and chemical stability of the retained austenite and the obtained mechanical properties. An evaluation of the lattice strain by means of electron-back-scattering-diffraction has also yielded a correlation to the obtained formability. The aim of this work is to present the interconnection between these microstructural features and propose hypotheses for the explanation of how these features influence the macroscopically observed properties.

scholarly journals Effect of Supra-Transus Deformation Conditions on Recrystallization of Beta Ti Alloy

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1278
Author(s):  
Chao Voon Samuel Lim ◽  
Yang Liu ◽  
Chen Ding ◽  
Aijun Huang
Keyword(s):  
Hot Deformation ◽  
Static Recrystallization ◽  
Dynamic Recovery ◽  
Texture Evolution ◽  
High Strength ◽  
Ex Situ ◽  
Mechanical Processing ◽  
Ti Alloy ◽  
Electron Backscattered Diffraction ◽  
Beta Ti Alloy

There is increasing usage of high strength Beta Ti alloy in aerospace components. However, one of the major challenges is to obtain homogeneous refined microstructures via the thermo-mechanical processing. To overcome this issue, an understanding of the hot deformation conditions effect on the microstructure, prior to and after annealing, is needed. In this work, the effect of strain levels, which is more precise than percentage of reduction, and strain rate under supra-transus deformation temperature on beta annealing are studied using a double cone sample. The Electron Backscattered Diffraction (EBSD) is used to determine the deformed microstructure and texture evolution, as well as the static recrystallized grains evolution using the ex situ annealing approach. This work provides evidence that the mechanisms of dynamic recovery and recrystallization, along with texture evolution, are affected by the deformation conditions, which in turn affected the subsequent static recrystallization during annealing. It will also be shown that high levels of strain do not necessarily lead to an increase in the rate of recrystallization. Finally, the results obtained provided several examples of guidance in designing the TMP processes for obtaining not only a refine microstructure, but a more homogeneous beta microstructure during the beta processing of Beta Ti alloy.

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