I'm curious about what the typical composition is of brass used in cartidge cases and how much pressure is required to extrude it at room temperature.
Thanks,
Wes S
- posted
17 years ago
extruding brass
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- posted
17 years ago
It's not extruded, it's drawn ... over horn dies, in multiple passes. Multiple annealings are often necessary for that kind of drawing.
LLoyd
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- posted
17 years ago
"Brass" is a pretty meaningless term- there are a good 20 different alloys commonly called brass. But "Cartridge Brass" is usually C 260, which is 70% Copper and 30 % Zinc.
Not all really big shell casings were necessarily made from this alloy, though- Brass is kinda like Chocolate Chip Cookies- everybody had their favorite recipe.
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- posted
17 years ago
Not always, look up "impact extruding". Lots of military brass is made this way. Basically one shot and it's done. You end up with a fairly soft case, but machine guns work well with softer cases and the case is discarded after one use anyway. Aluminum toothpaste tubes were made this way, too, complete with threads.
I don't have it right handy here, but I picked up a library discard called "Extrusion of Metals" that has a whole lot of details on the hows and whys of all sorts of manufacturing, not just cartridge cases. Very nice little book.
Stan