Cross wedge roll bonding process for laminated shafts forming: Interface microstructure, bonding mechanism, and parameter influence

Because of the common knowledge that the inner material of shafts is "dead weight" and plays a minor role in transmitting torque, a novel cross wedge roll bonding (CWRB) process is proposed to combine the advantage of efficient manufacturing and high performance for drive shafts. In this study, the principle of CWRB process was expounded in detail, in which a bimetallic billet can be directly rolled into a laminated shaft. Because the bonding behavior of CWRB shaft is driven by a complex three-dimensional deformation caused by uneven alternating stresses, the FE models, rolling trials, and performance characterizations were performed to sys-tematically study the interface quality, bonding mechanism, and parameter influence. Eighteen groups of physical experiments were performed to directly investigate the bonding quality of 42CrMo/Q235 laminated shafts. The corresponding FE models were constructed to reveal the bonding mechanism of CWRB interface by analyzing the stress and strain. The results reveal that the rolled 42CrMo/Q235 interface can be metallurgically combined under the action of a large radial compressive stress, and its microstructure undergoes interface bending, grain nucleation, and metallurgical integration. Although some rolled shafts have the defects such as interface debonding and central cracking, the rolled bimetal shafts were well combined under the reasonable parameters. The new CWRB process can be estimated to have industrial applications in high-end equipment in a low-cost manner. In addition, the bonding mechanism of CWRB process will be beneficial for fundamental research on bonding behavior of plastic deformation.