Metallurgical Examination of Punchings from Cast Turret of British A-12 Infantry Tank
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, 3-3/16 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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 29, 1941
- Accession Number
- ADA954293