Difference in bronze and iron cannons

[Stephen_D]

At what point did the makers have to switch to iron when making cannons? Did bronze cannons have a maximum bore, or projectile size? There are some rather large bronze cannons on display in town squares.

 

[1950DAVE]

Don't know about iron v bronze, but I have been reading " The Arms of Krupp" and there was still a lot of contention among military hierarchy about which was better bronze or steel into about the 1870's. Krupp won out eventually . The Firm developed steel that was far more resistant to the wear that was inherent in bronze and less likely to explode with heavy loads as happens with cast and wrought iron. I don't remember all the details but a four incher in bronze was considered too heavy as a field piece and bronze , being softer, could not stand up to the higher muzzle velocities attainable with steel. A long but interesting read. Suggested for those quarantined.
Dave

 

[zimmerstutzen]

The man who "poured" my bronze cannon barrel, told me bronze would stretch and swell if and when it failed, iron would crack and steel explode. He was an old timer with a back yard foundry and I do not know how much of what he said was gospel and how much was BS. I remember how amazed I was when I read that civil war cannons had an expected life span of a limited number of discharges. (Maybe due to work hardening?) It seemed so strange to me that a cannon might only be expected to be good for 1,000 discharges and then removed from service.

 

[Treestalker]

Bronze(brass) was traditional for Naval service being resistant to corrosion at sea, and was expected to 'rip' a hole rather than explode into pieces. Iron was more resistant to wear, but had to be made heavier to withstand the pressure of firing. A 12pdr sea cannon was maybe 1800lbs compared to a bronze 12 pdr at 1200. Look at pictures of Iron guns in theCivil War era Union Navy; they're big old hosses. Steel guns replaced Iron and brass into the modern age, but the tradeoff in power is wear. To this day even field guns have to have thier barrels re-lined fairly often, there just isn't a free lunch, hence the advancement of missile technology. Please understand I'm no expert, perhaps others will chime in to correct or add to my post, Geo.

 

[zimmerstutzen]

Bronze(brass) was traditional for Naval service being resistant to corrosion at sea, and was expected to 'rip' a hole rather than explode into pieces. Iron was more resistant to wear, but had to be made heavier to withstand the pressure of firing. A 12pdr sea cannon was maybe 1800lbs compared to a bronze 12 pdr at 1200. Look at pictures of Iron guns in theCivil War era Union Navy; they're big old hosses. Steel guns replaced Iron and brass into the modern age, but the tradeoff in power is wear. To this day even field guns have to have thier barrels re-lined fairly often, there just isn't a free lunch, hence the advancement of missile technology. Please understand I'm no expert, perhaps others will chime in to correct or add to my post, Geo.

Difference between brass and bronze: Brass is an alloy of copper and zinc, while bronze is an alloy of copper and tin. Bronze and Brass have different properties. A brass gun can blow apart more readily than bronze. IIRC brass will work harden more readily as well.

 

[tenngun]

First iron guns were made of staves of iron laid around each other. Red hot rings were placed over the slats and they would cool and shrink and bind the staves together making the barrel. The reason we call it a barrel is because it was an iron version of a wood barrel
In the late Middle Ages bell makers got real good at casting bronze bells, and that tech crossed over for gun making. By the eighteenth century they had leaned to cast iron barrels, and by the 1750s few large guns were bronze. Although it never went out of style. It seems to me in my mind eye Napoleon cannons of the WBTS were brass, designed for Napoleon 3, but his uncle had light bronze field guns.
early steel guns seemed to have had a tendency to turn in to Steel shrapnel. I’m thinking Dahlgren was killed by one of his guns exploding but it’s been many years since I read the story and easily could have the names misremembered

 

[Mulebrain]

I located the formula for cannon bronze, and had my brother pour some.
I forget the toughness scale, but it's way up there.

 

[Commodore Swab]

Bronze was more expensive than iron. Bronze would bulge whereas iron would explode. Both were used on naval ship, just look at the wrecks.

 

[zimmerstutzen]

Just an informational thing, since bronze bells were mentioned. above. There is a special alloy of bronze for bells with a much higher percentage of tin, which make a more rigid alloy and conducts sound vibrations better. This alloy is also used for cymbals and frequently used in large bronze plumbing valves. The problem in just melting down old plumbing fittings is that many are brass and some are bronze. I wanted to have a few thunder mugs poured but was leery when the foundry pointed to a pile of junk plumbing for a metal source. Their price was a bit more than I expected too.

 

[Essayons!]

Cost was really a consideration and the availability thereof (copper)...