Hot stamping of ultra-thin stainless steel for microchannels

Hot stamping of ultra-thin stainless steel for microchannels

GUO Nan, ZHANG Xianglu, HOU Zeran, YANG Daijun, MING Pingwen, MIN Junying

Abstract. Bipolar plate is one of the core components of a proton exchange membrane fuel cell (PEMFC), in which microchannels with regular distribution separate and distribute the fuel gas at the anode and oxygen/air at the cathode, and remove the reaction products from the cell. Dimensional deviations of microchannels affect assembly accuracy, thereby influencing the efficiency and performance of PEMFC. Ultra-thin stainless steel sheet is the most commonly used material for bipolar plate and stamping is an efficient way to form stainless steel microchannels. However, a challenge faced by the stamping process is how to improve the dimensional accuracy of stainless steel microchannels. Hereby we propose a hot stamping process of ultra-thin stainless steel sheet, which is of high potential to improve the dimensional accuracy of micro-channels. Uniaxial tensile tests are performed at room temperature (RT), 300, 600, and 900°C for an ultra-thin stainless steel 316L (SS316L). Results show that the strength of SS316L at 900 °C decreases significantly compared with that at RT, while the elongation is approximately 44%. Hot stamping process for stainless steel microchannels is developed, in which the ultra-thin sheet is heated by resistance heating. Stainless steel microchannels are hot stamped at 900°C, and the 3D profile and cross-sectional thickness distribution of which are measured. The measurement results show that the dimensional deviations of hot-stamped microchannels are lower than that of cold stamping, in terms of channel depth, rib width, and wall angle. Furthermore, the cross-sectional thickness distribution of the hot-stamped micro-channels has a similar trend as that of the cold stamping, and the thickness at the fillet is not significantly different (avg. + 1 μm) from that of the cold stamping.

Keywords
Stainless Steel, Hot Stamping, Microchannel, Dimensional Accuracy

Published online 4/19/2023, 6 pages
Copyright © 2023 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA

Citation: GUO Nan, ZHANG Xianglu, HOU Zeran, YANG Daijun, MING Pingwen, MIN Junying, Hot stamping of ultra-thin stainless steel for microchannels, Materials Research Proceedings, Vol. 28, pp 937-942, 2023

DOI: https://doi.org/10.21741/9781644902479-102

The article was published as article 102 of the book Material Forming

Content from this work may be used under the terms of the Creative Commons Attribution 3.0 license. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

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