Metallurgical Examination of Six 1 Inch Rolled Homogeneous Armor Plates Manufactured by Great Lakes Steel Corporation

An investigation has been completed on six 6 samples of 1-in rolled homogeneous armor manufactured by the Great Lakes Steel Corporation, The plates from which these samples were selected were reported to have exhibited exceptionally good shock resistance when tested with the 75 mm. T 21 proof projectile. The ballistic tests were conducted under the program correlating the effect of hardness on the ballistic properties of armor. The metallurgical tests fracture test and microscopic examination indicate that the steel was properly heat treated and would exhibit impact properties commensurate with its hardness. The steel quality was sufficiently poor in four 4 of the six 6 plates examined to be rejectable although it may not have influenced the results of the test applied, since in cross rolled steel laminations do not influence the cracking tendency appreciably unless the test is exceptionally severe or the quality is extremely poor.