Technical report ARCCB-TR-
03016. US Army ARDEC. Benêt Laboratories. Watervliet Arsenal, NY, 2003, - 23 p.The objective of the study was to gain further insights into the origin of chromium loss in tank guns. The present report summarizes the results of a study surveying chromium loss at various critical locations along a 120-mm M256 tank gun tube. Tube no. 6824 was selected because it had fired relatively few rounds (119), while still exhibiting initiation of all the typical chromium damage features in the chamber and bore of a 120-mm tube. Coating stresses were also computed with a finite element model to aid in the analyses. The data reveal a broad range of metallurgical effects related to erosion damage at the bore surface during firing. Establishing the cause of chromium loss in any specific case can be difficult because of the numerous contributing factors. Nevertheless, the present data show that high temperature oxidation at the chromium/steel interface is a common feature in both the chamber and the gun bore, indicating that steel oxidation is an essential factor in chromium loss. The interface oxidation occurs by gas penetration through chromium cracks that extend from the coating surface to the interface. This oxidation undermines the chromium coating and promotes chromium spallation, which then leads to pitting in the chamber and erosion in the bore.Contents:
Introduction.
Experimental Methods.
Results.
Discussion.
Summary.
References.
