What type of bronze...

[Musketeer]

for cannon barrels? Just curious. Historically "bronze" was just copper and tin, but today we have gajillions of alloys: phosphor bronze (closest seeming to the old stuff), aluminum bronze, manganese bronze, silicon bronze. Sheesh! What would be used today in a cannon barrel? Also, if one were to use phosphor bronze, what ratios between copper and tin would be good (C51000 @ 95/5, C54200 @ 90/10, etc.)? :hmm:

 

[sc45-70]

The machinery's handbook lists Leaded Gun Metal casting #63 as
86-89% copper
9-11% tin
1-2.5% lead
max. .25% phosphorus
max. .5% zinc and impurities

Don't know if this helps?

SC45-70

 

[Musketeer]

Thanks. That does help. :hatsoff: Now I at least have some basic numbers to go by. Back to the bronze spec sheets now to find something fairly similar. :hmm: :thumbsup:

 

[TheDoubleD]

The current bronze for cannon casting is Everdur http://www.anchorbronze.com/c65500.htm

The old bronze cannon using gunmetal bronze had a life of 1500 shoots before being condemned.

 

[Musketeer]

Thanks, DD. Interesting to see the high copper content of that alloy. That's why I asked about ratios. Pure copper is pretty tough but very soft. When you add alloying elements to it it becomes harder but also more brittle (in general). In studying Bronze Age weapons, I've read that high copper alloys made for weapons that were quite tough and break resistant but requiring more frequent attention to the edges and not producing the best edges in the first place, while lower copper alloys were harder and had better edges but tended to break rather than bend. I've recently taken a greater interest in cannons and was wondering how the tradeoff between toughness and hardness was dealt with in this particular application. It seems toughness would be more important, and the numbers for Everdur seem to support that. High copper content and silicon (which is also used to make steel tougher) as the primary alloying agent. Thanks again. :hatsoff: