Investigation On The Explosive Welding Technology And Its Microstructure And Property Of Titanium-steel Composite Plate

Titanium-steel composite plate combines the corrosion resistance of titanium and high strength of alloy steel, and it also has good thermal conductivity, etc, namely it has excellent comprehensive performance. Titanium-steel composite plate becomes an indispensable structural material for modern chemical industry and pressure vessel. Due to being firmly bonded instantaneously between the similar or dissimilar metals with large area, explosive welding is widely used in the preparation of metal composite plates. In this paper, the TA10-Q345 R and TA10-Q245 R composite plate with wide application prospect in chemical industry and pressure vessel are produced by explosive welding technology. The mechanical properties and microstructure of composite plates are systematically analyzed, and the explosive technology parameters are optimized under the experimental condition, so as to provide technological guidance for the practical application of composite plates.The results of mechanical properties tests show that the tensile strength of the two kinds of composite plates reaches 563.03 MPa and 467.37 MPa respectively, which is higher than that of composite plate through theoretical calculation. The shear strength of two composite plates reaches 266.1MPa and 217.7MPa respectively, which is higher than that of 196 MPa according to relative standard. The bending property of two composite plates is well, and no separation occurred in interface during inner or outer bending to 180 degree. Because the degree of plastic deformation is different in different regions of composite plates during explosive welding, the hardness of interface is the maxium, and the hardness in both sides of base metals gradually decrease with the increase of distance from interface.Microstructure observation indicates that the interface of composite plate is bonded with the pattern of wave, and with the characteristics of wave front swirl. The degree of plastic deformation is different generated in metals near both sides of interface. The adiabatic shear line appears in the side of titanium of TA10-Q345 R composite plate, and the interface wavelength and vortex size is larger than that of TA10-245 R composite plate. The elements Ti and Fe diffuse each other in interface of two composite plates, and the formation of diffusion layer can improve the interface bonding strength. The result of XRD shows that there are little amounts of intermetallic compound phase in interface of TA10-Q345 R composite plate. Tensile fracture scanning observation demonstrates that composite plate obviously presents the characteristics of ductile fracture. The TEM analysis shows that, the deformation mechanism near interface is mainly twin deformation, and nanocrystals are formed by the grains refinement, while a little far away from interface, the mechanism is mainly sliding deformation.Heat treatment is carried out to the two composite plates. The results show that adiabatic shear line in the side of titanium can be eliminated by heat treatment, and the tensile strength and shear strength decrease with the elevation of temperature. If the annealing temperature is too high, it will cause interfacial decarburization and the generation of compounds, even cause coarse grain. Consequently, under the experimental condition in this paper, the heat treatment process of TA10-Q345 R composite plate is determined as 600?×1.5h, and the TA10-Q245 R composite plate is 550?×1.5h.The chemical immersion experiment and electrochemical corrosion test are used respectively to evaluate the corrosion resistance of two conposite plates. The results show that, the rank of mass loss corrosion rate is as follows: TA10 < TA10-Q345 R < Q345 R < TA10-Q245 R < Q245 R. According to the dynamic potential polarization curves, the result shows that, the corrossion resistance of TA10 is the best, and TA10-Q345 R is the second, TA10-Q245 R is relatively low. It is corresponding to the test result of electrochemical impedance spectroscopy. Compared to the corrosion resistance of TA10, although the corrosion resistance of two composite plates slightly decreases, they still have better corrosion resistance under the experimental condition.