Repair Welded Cast Armor: Metallurgical Examination of Samples from Four Ballistically Tested 2-Inch Thick Plates
WATERTOWN ARSENAL LABS MA WATERTOWN ARSENAL United States
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The objective of this experiment was to carry out metallurgical examination of subject plates. Metallurgical examination including chemical analyses, macro-examination, hardness surveys, tensile and Charpy V notch impact tests, micro-examination, and Jominy hardenability tests, was carried out on the subject plates. Hardness surveys through the 2-inch thick weld metal repairs showed average hardnesses of 16.5 Rockwell C on one plate and 12.0 - 8.5 on the other three plates. Ballistic limits showed a decrease in penetration resistance with hardnesses. At the low hardness level of the weld metal developed by the quench and draw treatment, satisfactory V notch Charpy impact values were obtained for testing temperatures as low as -40 F. Hardenability determinations and micro-examination indicated that the weld metal has insufficient hardenability to develop a homogeneous martensitic microstructure on water quenching of 2-inch thick sections.