| 摘要 |
The projectile, adapted to be fired from an automatic cannon, comprises a frangible porous brittle generally cylindrical casing made of a molded sintered powder material preferably consisting predominantly of 60 to 100% type 316 stainless steel powder mixed with pure iron powder ranging from 40% by weight to zero. The powder material initially includes graphite powder ranging from about 0.2% to 2% by weight. The powder material is compressed into a casing mold to a molded density ranging from about 0.21 to about 0.24, perferably 0.23 of a pound per cubic inch. The molded powder is sintered in an inert atmosphere at a temperature ranging from about 1500 to about 1700, preferably 1600 DEG F. for a time sufficient to unite the molded powder into a brittle porous frangible casing. During sintering, the graphite powder vaporizes and escapes whereby porosity and frangibility are imparted to the casing. In molding the casing, a previously formed rotator band is inserted into the mold so that a portion of the casing is molded within the band whereby the casing and the band are securely united. The band has inwardly projecting teeth which interlock with the casing. The band is adapted to engage rifling within the barrel of the cannon. Upon the impact of the projectile with a target, the frangible casing disintegrates into granular fragments which are thrown outwardly with great energy.
|
