Static and dynamic mechanical behavior of high-strength 22SiMn2TiB armor steel and welded structure

High-strength advanced steel and welded structure are key for service safety and life. Static and dynamic compressive mechanical behavior of high-strength 22SiMn2TiB armor steel and welded structure is investigated, which are carried out by using universal testing machine and split Hopkinson pressure bar. The studied materials are obtained from high-strength steel matrix, welded seam and mix of them with interface, respectively. The strain rate in experiments covers the range of 0.001/s to 6000/s. The mechanical data involve stress-strain relations and strain rate dependencies of mechanical properties. The cracking behavior as well as the corresponding microstructures are characterized at different length scales from millimeter to micron scale by optical microscope and scanning electron microscope. The results show that static (0.001/s) and dynamic (5000/s) yield strengths are 1600 MPa and 2400 MPa for high-strength steel matrix, 400 MPa and 1200 MPa for welded seam, 950 MPa and 1600 MPa for mix of them with interface, respectively. Under dynamic loading, shearing occurs and results in the fracture. Along the interface of steel matrix and welded seam, cracks are firstly initiated and propagated. The relations of mechanical properties and fracture features are analyzed, where strain rate effect is mentioned. This work will guide the design and application for engineering structure.