We elucidate here the determining role of Nb interlayer on mechanical properties of Ti/steel clad plate fabricated by vacuum rolling cladding (VRC) as a function of different heating temperatures. A critical analysis on the clad interface via electron probe micro-analyzer, X-ray diffractometer and shear testing were conducted to investigate the influence of TiC, Fe-Nb and TiFe compounds and Nb-Ti solid solution on microstructural evolution and shear properties of Ti/steel clad plate. The inter-diffusion between Ti, C and Fe was effectively restrained by adding the Nb interlayer at heating temperature of 800 °C, and average shear strength of 279 MPa was achieved. With increase of heating temperature, Nb-Ti solid solution was formed at the Ti/Nb interface, which reduced mechanical properties of clad plate at 900 °C. At 1000 °C, TiC and Nb-Fe compounds and Nb-Ti solid solution were formed at the interface, and minimum average shear strength of 152 MPa was achieved. The detailed analysis on the clad interface suggested that ideal shear strength can be obtained through the addition of Nb interlayer and selecting appropriate heating temperature.

The titanium–steel clad plates were prepared by vacuum roll cladding. Ti–Fe compounds and TiC were observed at different cooling rates after rolling. Optical microscopy, electron microprobe analyser, X-ray diffraction and shear test studies were carried out to study the effect of Ti–Fe compounds and TiC on the ultimate microstructure and mechanical properties of titanium–steel clad plates. At a cooling rate of 6.2°C/min, TiC and Ti–Fe compounds seriously impacted the mechanical properties of the clad plate. At a cooling rate of 1.8°C/min, the thickness of the TiC layer was optimal much that the maximum shear strength of 296 MPa was obtained. At a cooling rate of 0.6°C/min, the thickness of the TiC layer was relatively thick, which affected the mechanical properties of clad plates.

In this study, a 304/20MnSi stainless-steel clad rebar was prepared by single-pass compression process using the MMS-200 Thermal Mechanical Simulator. The impact of different degrees of deformation and deformation temperature on microstructure evolution and the mechanical properties of stainless steel clad rebars were investigated. The study indicated that with the increase of the degree of deformation, the content of pearlite in a carbon steel matrix was increased, and the grains refined. The metallurgical bonding of the bonded interface was formed under high temperature and high extrusion force. With the increase of the deformation temperature, more bainite was obtained on the side of carbon steel, and the grain size increased. The obvious diffusion of Fe, Cr and Ni elements near the bonding interface resulted in higher microhardness of the stainless steel side and smaller microhardness of the carbon steel side. Moreover, the engineering stress-strain curves obtained by the tensile test showed that the plastic deformation of stainless steel and carbon steel was more coordinated. With the increase of deformation temperature and the degree of deformation, the tensile strength of the stainless steel clad rebar was as high as 690 MPa and the elongation was 26%, which was superior to the properties of the clad rebar prepared by other process parameters.