This paper describes the calculation of the parietal temperatures and thermo-mechanical stresses in a 120-mm chromium-coated gun barrel with Armour Piercing Fin Stabilize Discarding Sabot (APFS-DS) with wear-reducing additives. We consider in this study that the wear-reducing film material is attached on the surface of the bore. First we present software that computes pyrolysis processes in film material when hot internal ballistics propellant gases heat it. A numerical parametric study is then conducted, to determine the sensitivity of the barrel heating and cooling to the protective film thickness and to the Arrhenius's correlation parameters. The comparison between computation and parietal temperature measurements shows a good agreement: with 10 μm thickness of TiO2 as wear-reducing additives located on the chromium inner wall, the maximal value of the steel/chromium interface temperature is reduced (more than 100°C near the forcing cone). Thermo-mechanical computations for APFS-DS with TiO2, compared to APFS-DS, show that the compressive tangential stresses decrease (gradient and amplitude) within the chromium coating thickness and that the fast traction-compression cycle of the interface tangential stresses gets slower with time. So APFS-DS ammunition with TiO2 as wear-reducing additives will reduce and delay the gun barrel thermal erosion significantly.
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