Gouging—an obstacle to the development of hypersonic rocket sled test techniques—was mechanistically investigated through experimental and theoretical analyses. Typical gouges were analyzed using macroscopic and microscopic experiments to investigate the evolution of gouging. Quasistatic compression and Hopkinson bar experiments were performed to systematically study the thermoviscoplastic properties of U71Mn rail steel under wide ranges of the strain rate and temperature. The critical condition for gouging was derived based on a thermoviscoplastic constitutive model supplemented by a three-variable criterion for an adiabatic shear instability. The results showed the following. (1) Adiabatic shear bands (ASBs) form when stress reduction under the combined action of frictional heating and high-speed deformation exceeds the strain-hardening effect of the rail material. (2) The nonuniform deformation of the edges of ASBs leads to the generation of cracks that split the rail surface. As the ASBs expand, the cracks grow and coalesce, eventually causing the material to peel off, forming gouges. (3) The relationships among the temperature, strain rate, and strain at the onset of gouging can be determined based on the critical condition for the formation of ASBs in rail steel.

Little is known about the changes in physical and chemical properties of U71Mn steel during supersonic operation. In this paper, the impact adiabatic relationship of U71Mn steel in the range of 0.5~1km/s impact velocity was studied by flyer impact experiment. The data shows that with the increase of the impact velocity, the Hugoniot pressure of U71Mn steel increases significantly, but the increment of the Hugoniot temperature is relatively small. U71Mn steel does not undergo phase transformation under the impact of 0~23.5GPa pressure range.

As an ultra-high strength steel, 30CrMnSiNi2A steel has good plasticity, toughness and fatigue resistance, and it has been widely used in components that withstand explosion and dynamic shock loads. Therefore, the mechanical behavior of 30CrMnSiNi2A steel under strong impact load is the focus of attention. In this paper, the flyer impact experiment of 30CrMnSiNi2A steel is carried out in the pressure range of 0~20 GPa by a one-stage light air gun, and the impact adiabatic relationship of 30CrMnSiNi2A steel is studied. The Hugoniot pressure and Hugoniot temperature of 30CrMnSiNi2A steel were obtained by fitting the valid experimental data. The research results provide a reference for the application of 30CrMnSiNi2A steel in the field of explosion and impact.