Micro-Texturing onto Amorphous Carbon Materials as a Mold-Die for Micro-Forming

2013 ◽  
Vol 289 ◽  
pp. 23-37 ◽  
Author(s):  
Tatsuhiko Aizawa
Keyword(s):  
Amorphous Carbon ◽  
Glassy Carbon ◽  
Carbon Materials ◽  
Hot Stamping ◽  
High Strength ◽  
Solid Material ◽  
Carbon Substrate ◽  
Micro Forming ◽  
Dlc Coating ◽  
Polymer Sheets

Among various kinds of carbon materials, two types of amorphous carbon were employed as a mold-die material for micro-forming. Diamond like carbon (DLC) has sufficient strength and toughness as a protective coating onto the steel and WC (Co) substrates. Glassy carbon is a solid material which also has high strength even at the elevated temperature under inert gas atmosphere. These two materials are selected to fabricate the micro-textured mold-die as a mother tool to duplicate this micro-textured pattern onto the metallic and polymer sheets via table-top CNC micro-forming systems. High density oxygen-plasma etching and pico-second laser machining were developed to make micro-texturing onto the above two mold-die materials. In the former, micro-groove and micro-grid patterns were formed on the DLC coating; table-top CNC stamping system with CNC-feeder and cropper was used to duplicate these patterns onto the aluminum sheets in dry and at the room temperature. In the latter, micro-wedge patterns were imprinted onto the glassy carbon substrate; table-top CNC mold-stamping system with heating equipment was utilized for duplication of these patterns onto thermoplastic polymer sheets above the glass transition temperature. Formation of micro-textures onto these amorphous carbon materials provides us a new tool to fabricate the micro-patterned parts and devices in mass production via cold and hot stamping processes.

Electron-diffraction studies of amorphous carbon thin films

1993 ◽  
Vol 51 ◽  
pp. 1100-1101
Author(s):  
David A. Muller
Keyword(s):  
Thin Films ◽  
Electron Diffraction ◽  
Amorphous Carbon ◽  
Glassy Carbon ◽  
Spherical Structure ◽  
Local Ordering ◽  
Carbon Arc ◽  
Similar Appearance ◽  
Carbon Thin Films ◽  
Large Spherical

The sp2 rich amorphous carbons have a wide variety of microstructures ranging from flat sheetlike structures such as glassy carbon to highly curved materials having similar local ordering to the fullerenes. These differences are most apparent in the region of the graphite (0002) reflection of the energy filtered diffracted intensity obtained from these materials (Fig. 1). All these materials consist mainly of threefold coordinated atoms. This accounts for their similar appearance above 0.8 Å-1. The fullerene curves (b,c) show a string of peaks at distance scales corresponding to the packing of the large spherical and oblate molecules. The beam damaged C60 (c) shows an evolution to the sp2 amorphous carbons as the spherical structure is destroyed although the (220) reflection in fee fcc at 0.2 Å-1 does not disappear completely. This 0.2 Å-1 peak is present in the 1960 data of Kakinoki et. al. who grew films in a carbon arc under conditions similar to those needed to form fullerene rich soots.

N and S Co-doped Ordered Mesoporous Carbon: An Efficient Electrocatalyst for Oxygen Reduction Reaction in Microbial Fuel Cells

2020 ◽  
Vol 16 (4) ◽  
pp. 625-638
Author(s):  
Leila Samiee ◽  
Sedigheh Sadegh Hassani
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Microbial Fuel Cells ◽  
Carbon Materials ◽  
Reduction Reaction ◽  
Carbon Substrate ◽  
Promising Candidate ◽  
X Ray ◽  
Carbon Framework ◽  
Co Doped

Background: Porous carbon materials are promising candidate supports for various applications. In a number of these applications, doping of the carbon framework with heteroatoms provides a facile route to readily tune the carbon properties. The oxygen reduction reaction (ORR), where the reaction can be catalyzed without precious metals is one of the common applications for the heteroatom-doped carbons. Therefore, heteroatom doped catalysts might have a promising potential as a cathode in Microbial fuel cells (MFCs). MFCs have a good potential to produce electricity from biological oxidization of wastes at the anode and chemical reduction at the cathode. To the best of our knowledge, no studies have been yet reported on utilizing Sulfur trioxide pyridine (STP) and CMK-3 for the preparation of (N and S) doped ordered porous carbon materials. The presence of highly ordered mesostructured and the synergistic effect of N and S atoms with specific structures enhance the oxygen adsorption due to improving the electrocatalytic activity. So the optimal catalyst, with significant stability and excellent tolerance of methanol crossover can be a promising candidate for even other storage and conversion devices. Methods: The physico-chemical properties of the prepared samples were determined by Small Angle X-ray Diffraction (SAXRD), N2 sorption-desorption, Transmission Electron Microscopy (TEM), Field Emission Scanning Electron Microscopy (FESEM) and X-ray Photoelectron Spectroscopy (XPS). The prepared samples were further applied for oxygen reduction reaction (ORR) and the optimal cathode was tested with the Microbial Fuel Cell (MFC) system. Furthermore, according to structural analysis, The HRTEM, and SAXRD results confirmed the formation of well-ordered hexagonal (p6mm) arrays of mesopores in the direction of (100). The EDS and XPS approved that N and S were successfully doped into the CMK-3 carbon framework. Results: Among all the studied CMK-3 based catalysts, the catalyst prepared by STP precursor and pyrolysis at 900°C exhibited the highest ORR activity with the onset potential of 1.02 V vs. RHE and 4 electron transfer number per oxygen molecule in 0.1 M KOH. The high catalyst durability and fuel-crossover tolerance led to stable performance of the optimal cathode after 5000 s operation, while the Pt/C cathode-based was considerably degraded. Finally, the MFC system with the optimal cathode displayed 43.9 mW·m-2 peak power density showing even reasonable performance in comparison to a Pt/C 20 wt.%.cathode. Conclusions: The results revealed that the synergistic effect of nitrogen and sulfur co-doped on the carbon substrate structure leads to improvement in catalytic activity. Also, it was clearly observed that the porous structure and order level of the carbon substrate could considerably change the ORR performance.

Quenchability improvement and control simplification by ice mandrel in hot stamping of ultra-high strength steel hollow parts

2021 ◽  
Vol 64 ◽  
pp. 916-926
Author(s):  
Ali Talebi-Anaraki ◽  
Tomoyoshi Maeno ◽  
Ryohei Ikeda ◽  
Kazui Morishita ◽  
Ken-ichiro Mori
Keyword(s):  
High Strength Steel ◽  
Hot Stamping ◽  
High Strength ◽  
Ultra High Strength Steel ◽  
And Control

scholarly journals Forming a Flanged Hole When Quenching Press-Hardened Steel for Mechanical Fastening

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 721
Author(s):  
Yongjun Jeon ◽  
Hyunseok Choi ◽  
Dongearn Kim
Keyword(s):  
Hot Stamping ◽  
High Strength Steels ◽  
High Strength ◽  
Expansion Ratio ◽  
Hardened Steel ◽  
Continuous Increase ◽  
Pilot Hole ◽  
Experimental Apparatus ◽  
Mechanical Fastening ◽  
Hole Flanging

The recent stringent regulations on vehicle safety and reducing CO2 emissions have led to a continuous increase in the application of press-hardened steel (PHS) in automobiles. Similar to other high-strength steels, assembling PHS components using the common welding techniques employed in automotive production lines is significantly difficult because of the surface coating layers and the additives within. This difficulty in post-processing, attributed to its high strength, also limits the mechanical fastening of PHS components. Therefore, this study aims to develop a process for forming a structure enabling mechanical fastening by sequentially applying piercing and hole-flanging operations during the hot stamping process. Our experimental apparatus was designed to perform the hole-flanging operation after the piercing operation within a single stroke at a specific temperature during the quenching process of PHS. At high temperatures of 440 °C or higher, the hole-flanging process was conducted in a direction opposite to that of the piercing operation for creating the pilot hole. An extruded collar with a height of 8.0 mm and a diameter of 17.5 mm was achieved, which is hole expansion ratio(HER) of 82.5%.

Hot Stamping Processing Experiments of Quenchable Boron Steel

2008 ◽  
Vol 575-578 ◽  
pp. 299-304 ◽  
Author(s):  
Jun Bao ◽  
Zhong Wen Xing ◽  
Yu Ying Yang
Keyword(s):  
Heating Temperature ◽  
Hot Stamping ◽  
Cooling Water ◽  
High Strength ◽  
Processing Parameters ◽  
Boron Steel ◽  
Complicated Shape ◽  
Water Flow Velocity ◽  
Ultra High Strength Steel ◽  
Automotive Parts

The quenchable boron steel is a novel type of ultra high strength steel used for automotive parts so as to reduce the weight of the whole automobile. The hot stamping processing experiments for bending parts were studied. The influence of the hot stamping processing parameters, such as the heating temperature, the heat holding time and the cooling water flow velocity, on the mechanics properties and microstructure of the hot stamping parts is obtained. And then the optimal ranges of these parameters are determined, which provides a basis for the control of the hot stamping process applied in complicated shape parts’ production.

scholarly journals Tribological Behavior of Laser Textured Hot Stamping Dies

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Andre Shihomatsu ◽  
Sergio Tonini Button ◽  
Iris Bento da Silva
Keyword(s):  
Surface Topography ◽  
High Pressures ◽  
Hot Stamping ◽  
High Strength Steels ◽  
High Strength ◽  
Experimental Tests ◽  
Textured Surface ◽  
Laser Texturing ◽  
Stamping Dies ◽  
Before And After

Hot stamping of high strength steels has been continuously developed in the automotive industry to improve mechanical properties and surface quality of stamped components. One of the main challenges faced by researchers and technicians is to improve stamping dies lifetime by reducing the wear caused by high pressures and temperatures present during the process. This paper analyzes the laser texturing of hot stamping dies and discusses how different surfaces textures influence the lubrication and wear mechanisms. To this purpose, experimental tests and numerical simulation were carried out to define the die region to be texturized and to characterize the textured surface topography before and after hot stamping tests with a 3D surface profilometer and scanning electron microscopy. Results showed that laser texturing influences the lubrication at the interface die-hot sheet and improves die lifetime. In this work, the best texture presented dimples with the highest diameter, depth, and spacing, with the surface topography and dimples morphology practically preserved after the hot stamping tests.

Erzeugung duktiler Bereiche beim Formhärten*/Production of ductile areas in hot stamping – Creating areas with reduced strength using a tempering station

2019 ◽  
Vol 109 (10) ◽  
pp. 750-754
Author(s):  
B. Behrens ◽  
S. Hübner ◽  
S. Yarcu ◽  
K. Wölki ◽  
H. Maier ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Hot Stamping ◽  
High Strength ◽  
Car Body

Formgehärtete Bauteile sind aufgrund ihres Leichtbaupotenzials im Karosseriebau etabliert. Jedoch ist die mechanische und thermische Fügbarkeit aufgrund der hohen Festigkeit stark eingeschränkt. Ein Ansatz zur Verbesserung der Fügeeigenschaften ist die Erzeugung von weichen Fügezonen. Zur gezielten Einstellung von lokal angepassten mechanischen Eigenschaften beim Formhärten wurde daher eine dem Platinenerwärmungsprozess nachgeschaltete Temperierungsstation entwickelt, um Platinen vor dem eigentlichen Formhärten im Hinblick auf eine lokale Entfestigung zu temperieren.   Due to their lightweight, hot-stamped components are established in car body manufacturing. However, high strength limits the application of mechanical and thermal joining operations. One approach to improving the joining properties is the production of ductile joining areas. To achieve locally varying mechanical properties, a tempering station has been developed that is suited to locally adapt the blank temperatures right after the oven process and thus prior to the hot stamping, resulting in tailored mechanical properties after the hot stamping operation.

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