Effect of Heat Treatment Temperature on the Microstructure and Properties of Titanium-Clad Steel Plate Prepared by Vacuum Hot Rolling

Abstract

Titanium-clad steel plates are widely used in chemical equipment and nuclear power equipment due to their excellent corrosion resistance and high strength. However, the Ti-C and Fe-Ti compounds generated easily at the titanium/steel interface deteriorate the bonding strength of titanium and steel, especially in high-temperature service environments. In this study, pure Fe DT4 was chosen as an intermediate layer to control the formation of interfacial compounds. The plates of titanium/DT4/steel were manufactured by hot rolling technology with a small hole vacuuming. Then, titanium-clad steel plates were annealed at temperatures of 450 °C, 550 °C, and 650 °C to modify microstructure and properties. The interfacial microstructure composition, mechanical properties of titanium-clad steel plates, and the corrosion resistance property of titanium plates were studied in the as-rolled state and under different annealing temperatures. The results showed that compounds of TiC, FeTi, and Fe2Ti were generated at the interface of titanium-clad steel plates in the as-rolled state. After the annealing treatment, the types and quantities of the interfacial compounds were reduced, and these compounds were mainly TiC and FeTi at an annealing temperature of 450 °C. The interfacial compound was only TiC at an annealing temperature of 550 °C. However, the compounds of TiC and FeTi appeared at the interface at an annealing temperature of 650 °C. The variation of interfacial compounds determined the hardness and the shear strength of the titanium-clad steel plates. The more the interfacial compounds, the higher the hardness and the lower the shear strength. Therefore, when the annealing temperature was 550 °C, the interfacial hardness was lowest and the shear strength was highest. Meanwhile, the corrosion resistance of the titanium-clad plates showed significant improvement, indicating that this temperature provides favorable conditions for enhancing the corrosion performance of the plate.