| 摘要 |
965,889. Practice projectiles. MANNESMANN A.G. July 17, 1963 [July 26, 1962], No. 28326/63. Heading F3A. [Also in Division B5] A practice projectile has a core of compressed metal powder, the core after formation being treated to reduce the cohesion between the powder particles without affecting the shape of the core. The core may be formed under pressure in a mould and the cohesion reduced by mechanical action, e.g. hammering or static pressure, while the core is in the mould or after the core has been inserted in a sleeve. Ultrasonic vibration or alternating magnetic fields may be used to reduce the cohesion. The green strength of the core may also be reduced by immersion in an acid, especially when the core contains chemical compounds, e.g. sodium carbonate, which react with the acid, e.g. hydrochloric. To form the core iron powder may be mixed with zinc stearate. Magnesium oxide may be included in the mixture. The projectile shown has a core formed in three parts 2, 3, 4, which are inserted in a plastics sleeve 1. A tablet 5 of calcium chloride is inserted to prevent corrosion during storage. |
