Development of the Steel Sheet Battery Housing Concept (1st Report)
-Study of the Load Transfer Structure using Undercover-

Sadao Miyazawa･Shuki Nakamura･Artur Rekets･Kenichi Watanabe (Kobe Steel)

This paper reports a steel sheet battery pack structure with an uneven bottom surface of the tray.
This structure has a load transmitting path and cooling system using an undercover in the uneven tray space to reduce a battery pack height.

Development of the Steel Sheet Battery Housing Concept (2nd Report)
-Forming of the Cross Member with Complex Shapes using Hydraulic Presses-

Shuki Nakamura･Sadao Miyazawa･Rekets Artur･Kenichi Watanabe (Kobe Steel)

In this study, a forming method for the cross member used for the steel sheet battery housing was studied. The cross member has complex shapes with a continuous flange at the end, in addition to the shape given to the sidewalls to avoid the uneven bottom surface of the housing. The cross member was formed by hydraulic forming.

Development of Delayed Fracture Prevention Technology for 1470 MPa Class High-Strength Steel Sheet Parts

Kentaro Kobari･Kazuki Ishiguro (Suzuki Motor)･Yosuke Honda･Ryuji Shibue (BELLSONICA)･Shinnosuke Nishijima･Takayuki Nozaki (NIPPON STEEL)

In the development of steel plate press parts, the prevention of delayed fracture caused by the electrodeposition coating process and the corrosive environment in the market becomes an issue as the strength of materials increases. In the development of 1470MPa ultra high strength steel parts for new models, we report our efforts to prevent delayed fracture using CAE analysis.

Evaluation Method for Delayed Fracture of Steel Sheet by Four-point Bending Specimen
-Influence of Baking Treatment on Delayed Fracture Resistance in Ultra-high Strength Steel Sheets-

Junya Tobata･Hideyuki Kimura･Yuichi Matsuki･Toyohisa Shinmiya･Kouhei Ikeda･Kazuki Matsubara･Masanari Tomozawa (JFE Steel)

It is known that the delayed fracture resistance of cold-rolled steel sheets for automotive body structural parts is improved by Bake-hardening (BH) treatment. In this study, we investigated the changes in the microstructure of the steel sheets during BH treatment and the changes in the amount of hydrogen within the steel sheets after immersion testing by BH treatment. We also discussed the mechanism of improved delayed fracture resistance of the steel sheets due to BH treatment.

Prediction Method for the Edge Fracture of Steel Sheet Parts in the Automotive Crash

Yuki Taguchi･Kazuyuki Hamada･Mie Tachibana･Shota Chinzei (Kobe Steel)

The formability decreases as the strength of the material increases, which increases the risk of damage at the edge of the parts on the car crash. This paper reports the results of determining the fracture limit of the edge at various strain gradients in the basic test, and verifying the fracture prediction accuracy considering fracture limit of the edge in crash simulation.

Evaluation of Heat Exchanging Performances through Aluminum or Stainless Steel Plates for Thermal Management Parts

Atsutaka Hayashi･Jun-ichi Hamada (Nippon Steel Stainless Steel)･Tsuyoshi Tamogami･Akira Onishi (Nippon Steel Technology)

Heat exchange performances through aluminum or stainless steel plates were evaluated for thermal management parts. 0.5 to 2 mm thick those plates were used. Heat was input to one side of the plate, conducted through the plate, and transferred to running water on the other side of the plate. When the thickness was thick, heat exchange performance of aluminum plate was higher. However, when the thickness was thin, that of stainless steel was almost same as that of aluminum and it was considered that it depended mainly on heat transfer due to water flow.