Strength Prediction Model for Friction Stir Spot Welding of Aluminum Alloys – Part I

Toshiaki Fukuhara (Mazda)

We focus on friction stir spot welding (FSSW) as a critical technique for joining aluminum alloys and aim to establish a methodology for predicting joint strength. The strength of FSSW joints is closely correlated with the cross-sectional geometry of the joint, which varies according to welding conditions; however, quantifying this relationship has traditionally been challenging. In this study, we developed a strength prediction model by sequentially integrating flow analysis based on a particle method with a machine learning approach.

Development of BEV Battery Pack Concept and Key Technologies Utilizing Advanced Steel Sheets (First Report)
-Development of the key technologies to achieve high performance, process reduction, and space savings-

Naoki Kimoto･Yumi Saito･Yuuki Kitahara･Junichiro Suzuki･Atsuo Koga･Kunihiko Tohshin･Fumio Shibao･Taiga Taniguchi･Masahiro Kubo (Nippon Steel Corporation)

To address various challenges such as performance, weight reduction, high capacity efficiency, environmental compatibility, and cost-effectiveness required for BEV battery packs, a steel-based battery pack concept utilizing advanced steel sheets and related application technologies. The key technologies include eliminating electrodeposition coating and improving space efficiency, and performance evaluation methods to enable further advancements is also evaluated.

Development of BEV Battery Pack Concept and Key Technologies Utilizing Advanced Steel Sheets (Second Report)
-Development of Lower Case Solutions for Eliminating Electrodeposition Coating-

Taiga Taniguchi･Naoki Kimoto･Atsuo Koga･Kunihiko Tohshin･Hiroshi Yoshida (Nippon Steel Corporation)

To achieve cost reduction and CO₂ emission cuts, we developed a battery box using high-corrosion-resistant coated steel without electrodeposition coating. Spot welding achieved an appropriate current range but led to corrosion degradation and liquid metal embrittlement due to excessive surface heating. To address these issues, we attempted to control current density at the steel surface.

Development of Solution Technologies Contributing to Higher Functionality in Automotive Chassis

Ryo Urushibata･Yuki Kitahara･Yoshinari Ishida･Ryo Tabata･Masahiro Matsuba･Kenichiro Ohtsuka･Tasuku Zeniya (NIPPON STEEL)

Solution technologies contributing to higher functionality in automobile chassis parts are introduced. The synergistic effect of advantaged steel sheets and solution technology gives part weight, cost, and LCA an advantage. As an example, a development case in front lower arm is presented.