Effect of hot rolling with a corrugated roller and warm rolling with a flat roller on the surface cracking and interfacial microstructure of the titanium side of titanium/steel clad plates

Considering the issues of periodic cracks on the metal surfaces of difficult-to-deform sides and large residual stresses after rolling during the preparation of metal composite plates with poor plasticity via the wave-flat continuous rolling process, this study proposed the preparation of corrugated roll, hot-rolling-flat roll warm rolling (hot-warm rolling) to prepare TC4/304SS composite plates. The first pass involved corrugated hot rolling, where the rolling temperature was 900°C, and the reduction rate was 30 %. The sheet after the first pass was maintained at 550°C, 600°C, 650°C, and 700°C for 30 min, and then the second pass after flat roll rolling with a total reduction rate of about 40 % was carried out. Experimental results indicated that interfacial cracks persisted at a warm rolling temperature of 550 °C, while intermetallic compounds formed at the interface when the temperature was increased to 650 °C and 700 °C, significantly degrading the bonding performance.The TC4/304SS composite plate with excellent flatness, surface quality, and shear strength (maximum shear strength of 397.7 MPa) was obtained when the warm rolling temperature was 600°C. EBSD(Electron Backscatter Diffraction) microscopic analysis revealed that the TC4/304SS composite plate rolled by hot- warm rolling experienced partial recrystallization and lower dislocation density than that rolled by traditional continuous rolling, which proved that the process played a positive role in improving the plasticity of the composite plate. This effectively addressed the TC4/304SS composite plate TC4 surface crack problem, improved the flatness of the shape after rolling, reduced the residual stress, and provided a reference for the preparation of high-performance difficult-to-deform metal composite plates.