Accession Number:

ADA231429

Title:

Failure Analysis of the LAU-7/A Launcher Retention Band Assembly

Descriptive Note:

Final rept

Corporate Author:

ARMY LAB COMMAND WATERTOWN MA MATERIAL TECHNOLOGY LAB

Report Date:

1990-11-01

Pagination or Media Count:

36.0

Abstract:

The U.S. Army Materials Technology Laboratory MTL conducted a comprehensive metallurgical examination of the launcher retention band assembly to determine the probable cause of failure. The assembly secures the aft end of a nitrogen receiver which is part of the LAU-7A Guided Missile Launcher located on the FA-18 Navy Jet. The retention band failed near the weld joint during service. Visual inspection of the assembly revealed areas conducive to crevice corrosion. Deep depressions produced by the spot welding procedure were found on the surface of the base. Wear and galling marks that were caused by fasteners that had bottomed out on surface of the band were observed. Light optical microscopy of the fracture surfaces verified the existence of beach marks. It was determined by metallographic examination that the microstructure of the type 17-4 precipitation hardened PH stainless steel retention base was predominately tempered martensite with islands of ferrite while the type 301 stainless steel band showed signs of prior cold working.

Subject Categories:

  • Elastomers and Rubber

Distribution Statement:

APPROVED FOR PUBLIC RELEASE