Accession Number : ADA954179

Title :   Metallurgical Examination of Two Disston 1-1/2 Inches Rolled Homogeneous Armor Plates,


Personal Author(s) : Reed,E. L. ; Matthews,N. A.

Report Date : 13 JAN 1942

Pagination or Media Count : 29

Abstract : The object was to determine the metallurgical characteristics of good and poor quality Disston 1-1/2 rolled homogeneous armor plates, including chemical analyses, macroscopic and microscopic examination, physical tests, and hardness surveys. The conclusions were: (1) The defective plate from Heat 1843 (D3) was heat treated to a too high hardness (311 Brinell); (2) The macrostructure of the poor heat 1843 (D3) as revealed by the Oberhoffer reagent indicated that the dendritic structure was improperly refined during the hot rolling operation; (3) The satisfactory plate from Heat 1830 (D4) which was correctly heat treated to a hardness of 293 Brinell showed the presence of some center line banding of a relative high carbon content although it was not associated with a marked aggregation of nonmetallic inclusions. This condition, noted previously in other samples of armor, is not related to spalling when the plate is heat treated to the correct hardness; (4) Heats 1830 (D4) and 1843 (D3) are free from pronounced segregated nonmetallic inclusions; and (5) For the purpose of revealing grain boundary carbides it has been determined that a 10% chromic acid electrolytic etch has been found superior to the Murakami's reagent or the alkaline sodium picrate.


Subject Categories : Metallurgy and Metallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE