Metallurgical Examination of Bore Surface Damage in a 5 Inch Gun.
WATERVLIET ARSENAL N Y
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Three metals, Armco iron, 1018, and gun steel, were tested in a 5-inch, 54 caliber instrumented gun. Four propelling charges, Naco, Pyro, M-26 plus talc, and M-26 plus silicone oil, were used during the experiments. The test plugs were positioned 2.6, 14.6, and 20.6 inches ahead of the origin of rifling. After firing, the specimens were sectioned, polished, and examined metallographically. Hardness readings were taken in the thermally altered material and surface residues were examined spectroscopically. The position closest to the origin of rifling had the maximum thermally altered material. Naco caused the least amount of transformed material of any of the propellants. For the experimental conditions used in this study, one round produced the same kinds of layers on the test plugs that are observed on field fired tubes. Author