Vol. 9 No 5 October 2001
Case Technology for Tank Gun Ammunition
This technology is based on felting (moulding) process. During felting, fibres from the dilute slurry deposit on the felt. They are then dried and treated with solvent for gelatinisation, compacted at high pressure and thereafter dried to achieve high strength and trimmed to the required dimensions.
High performance guns suffer fast erosion of gun barrel due to high temperature and high velocity of burning gases of the propellant. This erosion brings down the performance and accuracy and shortens the barrel life drastically leading to condemnation of costly gun barrel too early in its ballistic life. The erosion phenomenon has been ascribed to a combination of three factors, namely thermal, chemical, and mechanical.
DRDO has successfully solved the problem of barrel erosion by developing titanium dioxide-wax and talc-wax additive liners. The additive liners provide relief from the thermal factors by providing a cool boundary layer in barrel. This layer acts as a buffer between the hot combustion gases and the inner surface of the barrel. In addition, use of refractory metal oxides in the composition succeeds in providing a coating of fine powder on the inner surface of the barrel which reduces the turbulence of combustion of gases near the surface and prevents the passage of heat raDIATion .
The talc-wax additive liner has effectively increased the barrel life to more than 1000 rounds, whereas the Titanium dioxide-wax additive liner has increased the barrel life to around 500 rounds as against 250 rounds when no additive liner was used. These liners have been inducted into the Services and bulk production of both types of liners has commenced.