Laser welding for hot-stamped tailor-welded blanks with high-strength steel/high-energy absorption steel

2014 ◽  
Vol 26 (3) ◽  
pp. 032007 ◽  
Author(s):  
Minjung Kang ◽  
Cheolhee Kim
Keyword(s):  
Laser Welding ◽  
Energy Absorption ◽  
High Strength Steel ◽  
High Strength ◽  
High Energy ◽  
Tailor Welded Blanks ◽  
High Energy Absorption

scholarly journals Twist and lock: nutshell structures for high strength and energy absorption

2021 ◽  
Vol 8 (8) ◽  
pp. 210399
Author(s):  
Nannan Xiao ◽  
Martin Felhofer ◽  
Sebastian J. Antreich ◽  
Jessica C. Huss ◽  
Konrad Mayer ◽  
...  
Keyword(s):  
Energy Absorption ◽  
Imaging Techniques ◽  
High Strength ◽  
High Energy ◽  
Raw Material ◽  
Pistachio Shell ◽  
Composition And Structure ◽  
Depth Study ◽  
High Energy Absorption

Nutshells achieve remarkable properties by optimizing structure and chemistry at different hierarchical levels. Probing nutshells from the cellular down to the nano- and molecular level by microchemical and nanomechanical imaging techniques reveals insights into nature's packing concepts. In walnut and pistachio shells, carbohydrate and lignin polymers assemble to form thick-walled puzzle cells, which interlock three-dimensionally and show high tissue strength. Pistachio additionally achieves high-energy absorption by numerous lobes interconnected via ball-joint-like structures. By contrast, the three times more lignified walnut shells show brittle LEGO-brick failure, often along the numerous pit channels. In both species, cell walls (CWs) show distinct lamellar structures. These lamellae involve a helicoidal arrangement of cellulose macrofibrils as a recurring motif. Between the two nutshell species, these lamellae show differences in thickness and pitch angle, which can explain the different mechanical properties on the nanolevel. Our in-depth study of the two nutshell tissues highlights the role of cell form and their interlocking as well as plant CW composition and structure for mechanical protection. Understanding these plant shell concepts might inspire biomimetic material developments as well as using walnut and pistachio shell waste as sustainable raw material in future applications.

High-Strength Steel Hot Forming Mechanics Performance and Characteristic Experimental Study

2016 ◽  
Vol 693 ◽  
pp. 800-806
Author(s):  
You Dan Guo
Keyword(s):  
Yield Strength ◽  
High Strength Steel ◽  
High Strength ◽  
High Energy ◽  
Absorption Capacity ◽  
Hot Forming ◽  
Gas Content ◽  
Strength Increase ◽  
Gradual Change ◽  
Forming Process

In high-strength steel hot forming, under the heating and quenching interaction, the material is oxidized and de-carbonized in the surface layer, forming a gradual change microstructure composed of ferrite, ferrite and martensite mixture and full martensite layers from surface to interior. The experiment enunciation: Form the table to ferrite, ferrite and martensite hybrid organization, completely martensite gradual change microstructure,and make the strength and rigidity of material one by one in order lower from inside to surface, ductility one by one in order increment in 22MnB5 for hot forming;Changes depends on the hot forming process temperature and the control of reheating furnace gas content protection, when oxygen levels of 5% protective gas, can better prevent oxidation and decarburization;Boron segregation in the grain boundary, solid solution strengthening, is a major cause of strength increase in ;The gradual change microstructure in outer big elongation properties, make the structure of the peak force is relatively flat, to reduce the peak impact force of structure, keep the structure of high energy absorption capacity;With lower temperature, the material yield strength rise rapidly,when the temperature is 650 °C, the yield strength at 950 °C was more than 3 times as much.

An Experimental Evaluation of Energy Absorption of TRIP Steel by Small Punch Test

2016 ◽  
Vol 725 ◽  
pp. 60-65
Author(s):  
Asuka Hayashi ◽  
Takeshi Iwamoto
Keyword(s):  
Energy Absorption ◽  
Trip Steel ◽  
Dynamic Condition ◽  
High Strength ◽  
High Energy ◽  
Bending Test ◽  
Absorption Characteristic ◽  
Small Punch ◽  
Three Point Bending ◽  
Punch Test

TRIP steel possesses high strength and excellent ductility. In addition, it is possible that TRIP steel indicates high energy absorption so that TRIP steel is expected to apply to automotive members. To design the members made of TRIP steel, it is important to clarify its energy absorption characteristic at various deformation rates. In the previous study, the energy absorption characteristic of TRIP steel is evaluated by J-integral under quasi-static to dynamic condition by using a thick specimen based on ASTM standard. However, by using such thick specimens, it is difficult to conduct the three-point bending test under impact condition because of high ductility in TRIP steel. A small punch (SP) test is the experimental method which can evaluate fracture parameters such as J-integral. By using a conventional use of small specimen in the SP test, it is possible to evaluate J-integral of TRIP steel under impact deformation. In this study, energy absorption characteristic of TRIP steel is investigated by SP test under different deflection rates. Then, the relationship between the values of J-integral obtained by previously conducted three-point bending test and the SP test of TRIP steel is discussed.

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