The roll bonding process of the sandwich sheet is a preferable production method to manufacture multilayer sheets and it needs clear investigation because some industrial parts cannot fulfill all of the requirements by single-layer material. In this study, a theoretical model of roll bonding has been reviewed and hot sandwich rolling processes with different plate thickness and flow stress were numerically investigated. The contact pressure-dependent bonding properties in the deformation zone were defined. Then, the liner thickness and reduction ratio are important parameters to determine the total deformation zone. When the thickness of the liner becomes large, unbonded length of deformation can be a serious problem and at the same time, the good bonding strength can be found at a higher reduction ratio of the thinner liner.

High strength aluminium alloys have drawn a lot of attention because of the expanding demand for lightweight vehicle design in the automotive sector. Due to poor formability at room temperature warm and hot forming have been advised. However, warm and hot forming methods need more steps in the production process and an advanced tooling system. In contrast, since ordinary tools can be used, forming sheets at room temperature in the W-temper condition is advantageous. However, a significant problem that must be resolved during the use of this technique is the springback of supersaturated sheets and their thinning. In this study, the high strength aluminium alloy was solution heat treated, and a U-shaped bending test was carried out at different time periods between W-temper heat treatment and forming operation. As a result, it is noted that the springback is highly dependent on the time between W-temper heat treatment and forming operations, and the change in shape increases with increasing time. The change in shape after forming was also evaluated using numerical simulation aiming to validate the experimental result. To determine the material parameters of the kinematic hardening model for numerical simulation, uniaxial tension-unload tests were performed under different ageing conditions.