Evaluation of joint strength and uniformity of clad layer thickness of bimetallic wire rod

The results of experimental studies of the shear resistance of layers of a cylindrical bimetallic conversion blank along the plane of contact between the base (45 steel core) and cladding (12Kh18N10T steel shell, 22 % volume fraction) layers are presented. Combined hot rolling (packet rolling) was carried out using a diamond-square pass system. The effect of the unsteady rolling process on the bond strength of layers in bimetal cross-sections at distances of 150, 300, and 450 mm from the front and rear ends of a 50x50 mm rolled blank was studied. This made it possible to determine the required length of the removed sections of the rolled blank. Statistical analysis of the experimental data showed that removing 300 mm of the front and rear ends of the rolled blank, while achieving an average shear stress of τcp = 300-330 MPa, guarantees the subsequent production of bimetallic wire rod with the required bond strength for successful wire production. Uneven distribution of the cladding around the core in 14.2 mm diameter bimetallic wire rod obtained by hot rolling a composite cylindrical billet of 45 + 12Kh18N10T steel using the oval-square pass system was established. Computer simulation of the rolling process was employed using the SIMULIA/Abaqus software package. The simulation demonstrated the optimal rolling sequence using the round-round, round-oval, and then oval-square pass systems with elongation values of 1.136, 1.263, and 1.282, respectively. This improves the uniformity of the cladding distribution around the core and improves metal finishing during the initial and final rolling using the prefinishing oval-round-round system with elongation values of 1.2, 1.148, and 1.14, respectively.