Metallurgical Examination of Twelve 2 1/2 Inch Thick Rolled Homogeneous and Sixteen 2 1/2 Inch Thick Face Hardened Armor Plates Manufactured by Carnegie-Illinois Steel Corporation
Final memorandum rept.
WATERTOWN ARSENAL LABS MA
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A metallurgical examination was conducted on twelve 12 2 12 in thick rolled homogeneous and sixteen 16 2 12 in thick rolled face hardened armor plates manufactured by Carnegie-Illinois Steel Corporation on OCO-D project 1558. The results of this investigation that, in general, the steel soundness of the face hardened plates was inferior to that of the homogeneous plates. In this connection, the face hardened plates had more pronounced directional properties than the homogeneous plates. The average Brinell hardness of the homogeneous plates was 247-262. The average Brinell hardness of the face hardened series was found to be face, 465-690, and core 208-243. The depth of the effective case at Rockwell C 50 varied from .26 in- 40-in. from the plate 10 plates tested while in two face hardened plates the case depth was .09-in - .16-in from face of plate. In general, the homogeneous and face hardened plates were properly heat treated resulting in fibrous fractures, good V-notch impact properties and a satisfactory microstructure.