Effect of Crystallographic Texture, Retained Austenite, and Austenite Grain Size on the Mechanical and Ballistic Properties of Steel Armor Plates
Final technical rept. 1 Jul 1975-30 Jun 1976
UNITED STATES STEEL CORP MONROEVILLE PA RESEARCH LAB
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The ballistic performance of a medium-carbon 5Ni-Si-Cu-Mo-V steel processed to plates with various degrees of textures, various amounts of retained austenite, and various austenite grain sizes has been studied. Results show that, with 0.50 caliber projectiles and 0 degree obliquity, the V50 ballistic limit of nearly random-textured plates is around 2030 to 2100 fps 666 to 689 mps, at a hardness of about 53.5 to 54.5 RC. For approximately the same hardness and in-plane mechanical properties, the ballistic limit of strongly 112 111 textured plates increased with increasing texture intensity. A ballistic limit of about 2360 fps 774 mps was observed for the strongest texture produced in plates rolled 80 to 90 percent at 1500 F 815 C before quenching. With this increased ballistic limit, the tendency for spalling also increased. At a constant strain rate, the spalling resistance appears to correlate qualitatively with the through-thickness notched tensile strength. Tempering quenched plates with a random texture at various high temperatures 1100 to 1300 F or 593 to 704 C to vary the retained-austenite contents greatly reduced the ballistic limit, primarily because of the lowered hardness. For this range of low hardness and low ballistic limit, the latter increased with increasing retained-austenite contents, but with decreasing hardness.
- Metallurgy and Metallography