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

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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.

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


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

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