Accession Number : ADA953864

Title :   Radial Expansion of Cannon,

Corporate Author : WATERTOWN ARSENAL LABS MA

Personal Author(s) : Mesick,B. S. , Jr

Report Date : 1933

Pagination or Media Count : 43

Abstract : The radial expansion methods of the Navy differ from those of the Ordnance Department, U.S. Army, both in theory and in practice. Based on the principle of stressing the outer layers of the cannon just to the elastic limit in tension by the application of a pre-determined interior radial pressure calculated from the minimum specified elastic limit of the metal of which the cannon has been formed, the Navy method fails to take into account the effect of elastic limits higher than the minimum specified. The Army method overcomes this fault by using the elastic limit of the actual metal being cold worked, as determined by the average of tangential tensile tests taken as a part of routine acceptance tests, in all pressure computations. The resulting permanent deformation of the bore by the Navy method will vary from 0 to 4 percent, while Watertown Arsenal has been able to produce consistent results of 6 percent with variations of less than + or - 0.5 percent for all calibers. In making their strength calculations for the finished gun, the Navy considers only the increase in strength due to self-hooping or initial compression at the bore, while the Army considers the change in physical properties of the metal itself as well as the initial compression produced by the cold working pressure. Some of the mechanical features of the apparatus used by the Navy in their method of cold working are superior to the Army equipment and are recommended for incorporation by the Army in their new designs.

Descriptors :   *Expansion, *Radial stress, *Elastic properties, *Limitations, Metals, Cold working, Ordnance, Guns, Acceptance tests, Tangents, Tensile testers, Physical properties

Subject Categories : Guns
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE