Steel Erosion Produced by Double Base, Triple Base, and RDX Composite Propellants of Various Flame Temperatures

Experimental studies of steel erosion were performed using three propellant types (i.e., double base, triple base, and RDX composite). Propellants of each type were formulated to have isochoric flame temperatures of approximately 2700, 3000, and 3300K. The experiments (performed in a combustor that used conventional perforated grains) produced mass loss data over a range of pressure-versus-time (P-T) programs. The propellant charge weights were selected to produce rather severe melt-and-wipe-off type of erosion. The combined effects of varying the propellant type and the P-T program produce interactions which greatly complicate the interpretation of the erosion- producing processes. In an effort to relate the results to gun barrel erosion, the various propellant grains and duty cycles were compared on the basis of equivalent muzzle velocity. Hence, the erosion data were correlated in terms of the integral of P-T. For equivalent P-T integrals and flame temperatures, RDX composite propellant grains were clearly the most erosive, whereas the erosivity was less for the double and triple base propellant grains (which has similar erosivity). Within a propellant type, the hottest propellants (3300K) generally produced mass losses twice as great as the nominal propellants (3000K). Prepared in cooperation with Princeton Univ., NJ.