Metallurgical Evaluation of Inner Wall Softening in a Tow Flight Missile Case

Failure occurred in two TOW flight missile cases in unrelated launchings. After an extensive investigation, it was concluded that stress corrosion was the most likely cause of failure. Subsequent to this conclusion, inner wall softening was observed in an unfired TOW flight missile case. Questions arose as to how the softening occurred and whether or not it had contributed to the failures. This report contains the results of a study which resolved that inner wall softening could not have been present in the failed missile cases.