Recent products, targeting the limit design design limit, must satisfy a strict specification at every stage of the production process. The joining areas between the structural members of these products are characterized by the ease of which trouble occurs there as a result of discontinuity in form and residual stress. At Hitachi Research Laboratory, over a long time, we have been contributing to technical development for making highly reliable joined parts.
As main joining technologies, arc welding, laser welding, and friction-stir welding (FSW; upper photo) are being developed. To develop more advanced joining technology, we are, for example, clarifying phenomena by using special observation systems and performing computer simulations. The left figure is an example of the melting area section during laser welding. What's more, aiming to prevent cracks being generated during welding, we are using equipment for limiting welding cracks and researching into new materials.
