Honda develops new tech to weld together steel and aluminium, achieves both weight reduction and increased rigidity in front sub-frame

September 21, 2012: Honda Motor Co has earlier this month announced that it has developed a technology for the continuous welding of the dissimilar metals of steel and aluminium. It has applied it for the first time in the world to the sub-frame of a mass-production vehicle, a key component of a vehicle body frame. Honda will adopt this technology first to the North American version of the all-new 2013 Accord, which has gone on sale in the United States on September 19 and will expand application sequentially to other models.

Striving to reduce vehicle weight in order to increase fuel economy, Honda focused on Friction Stir Welding (FSW) and developed a new technology for the continuous welding of steel and aluminium. This technology generates a new and stable metallic bonding between steel and aluminium by moving a rotating tool on the top of the aluminium which is lapped over the steel with high pressure. As a result, the welding strength becomes equal to or above conventional Metal Inert Gas (MIG) welding.

This new technology contributes to an improvement in fuel economy by reducing body weight by 25 percent compared to a conventional steel sub-frame. In addition, electricity consumption during the welding process is reduced by approximately 50 percent. It also enabled a change in the structure of the sub-frame and the mounting point of suspension, which increased the rigidity of the mounting point by 20 percent and also contributed to the vehicle's dynamic performance.

Furthermore, Honda established a new method to apply this technology to mass-production vehicles. Conventionally, FSW required use of large equipment, but the carmaker has developed an FSW continuous welding system applied to a highly versatile industrial robot. This system also can be used for aluminium-to-aluminium welding and thus, the welding system with the same specifications can be used for production of a full-aluminium sub-frame.

Honda also developed a non-destructive inspection system using a highly-sensitive infrared camera and laser beam, which enables an in-line inspection of the bonding location for every unit.