Abstract
Global warming and decreasing energy supply are serious issues we face today. Automobile industries aim to solve these problems by improving fuel efficiency and reducing CO2 emission. Therefore, there are strict demands for light-wright, fuel efficient cars. One way to reduce car body weight is by replacing steel with aluminum alloy.
Under such a background, an effective steel-aluminum alloy joining technique is required. However, removal of aluminum alloy surface oxide and the control of interface intermetallic compound are difficult tasks to overcome. Furthermore, galvanic corrosion is also a problem when dissimilar materail joint is applied to automobile outer panels.
To solve these problems, we aimed to reduce the welding process temperature by focusing on low temperature eutectic reaction between aluminum and zinc at 382°C.
As a result, we achieved to remove aluminum alloy surface oxide at low temperature, controlled intermetallic compound formation by heat input reduction, and finally achieved higher tensile strength. In this study, we developed dissimilar materials joining technique using Resistance Spot Weling. In addition to static tensile properties, we have already achieved all the other perofrmance requirements for vehicle application, including fatigue properties, high-speed tensile properties, low-and high-temperature tensile properties and anticorrosion performance.
