Accession Number:

ADA954293

Title:

Metallurgical Examination of Punchings from Cast Turret of British A-12 Infantry Tank

Descriptive Note:

Corporate Author:

WATERTOWN ARSENAL MA

Personal Author(s):

Report Date:

1941-10-29

Pagination or Media Count:

28.0

Abstract:

The purpose of this investigation was to determine the metallurgic characteristics of these punchings blown from the case turret of the British A- 12 Infantry Tank by 75 mm, M61 A.P. shell. The carbon content 0.44 is considered too high for the thickness of armor employed in the construction of this turret namely, 3-316 in thick. There was no evidence of homogenization as indicated by the presence of segregations of massive carbides in the intermediate fillings. The turret was heat treated to a realtively high hardness 302-340 Brinell. The cast armor is considered inferior quality material showing evidence of poor deoxidation practice and occasional hairline cracks in the metal. The microstructure of the samples revealed ia fairly unifrom acicular structure with an occasional segregation of massive carbides and nonmetallics in the dendritic fillings. Unsoundness, lack of homogenizing treatment, and relatively high hardness are the probable causes of failure.

Subject Categories:

  • Properties of Metals and Alloys
  • Armor

Distribution Statement:

APPROVED FOR PUBLIC RELEASE