High-speed impact of low-carbon alloy steel plates by ultra-high strength blunt projectiles

To investigate the ballistic resistance and failure mode of three different low-carbon alloy steel plates subjected to ultra-high strength low alloy steel projectiles, we used the typical bulletproof special steels SS and AS and the commonly used Q235A steel for our study in the present research, obtained their static tensile and compression performance and the dynamic mechanical behavior at the strain rate of 1 000 to 6 000 s^-1 by static tension, compression and split Hopkinson pressure bar tests respectively, and analyzed the relationship between material composition and mechanical performance. We also obtained the ballistic limits of these plates (14.5~15.9 mm thick) subjected to two ultra-high strength low alloy steel projectiles by ballistic gun experiments. Furthermore, we compared the specific energy absorption and failure mode of the steel plates under various conditions and analyzed the relationship between the mechanical performance and the failure mode. The results showed a positive correlation between the ballistic resistance and the yield strength, but the differences between the ballistic resistances of the three steel plates are less than that between the yield strength. Finally, the failure mechanism of different steel plates is correlated with different mechanical parameters: for the AS steel plates with a high content of Si and Mn, the main determinant of fracture failure is its shear strength, as is characterized by great hardness and brittleness, while for SS and Q235A steel plate with a low content of Si and Mn the main determinant is its compressive and shear strength, as is characterized by good plasticity.