Working bronze

[Chuck Hancock]

I want to fabricate some support brackets out of silicon bronze. I have some solid rod, and my idea is to cut pieces to length and heat and flatten each end using a torch/anvil/hammer, then drill a hole through the flatten portion which will have been bent at a desired angle to allow for mounting w/ lag screws. My question is, does this essential forging process deteriorate the strength of silicon bronze? Is there a proper cooling/quenching routine that should be observed?

[NormMessinger]

Heating the bronze will take the temper out. Bronze is tempered by work hardening, shot peening, hammering, tumbling, etc, so quenching will not restore it. However, it may still be strong enough after you shape it if you use a thick enough piece, eh.

[RonW]

Ferrous metals (steel) are tempered by heating and quenching in oil-water,etc.Non ferrous metals,bronze,brass,copper,silver are just the opposite and are tempered by heating and slowing cooling like covering with sand.Hammering will work hardening a non ferrous metal like bronze.If you just heat it and beat it without quenching it, it will end up harder then when you started, just don,t quench it.

[Big Red]

If you heat the bronze to near cherry, and allow it to cool (fast or slow) it will be softer than before. Since you have bar stock, it was probably formed by rolling/drawing, yes? This will harden the metal.

Copper is hardened by working it, such activities as already mentioned, most notably bending, (obviously its alloys have different properties, bonzes and brasses are harder for a start).

To soften the copper we heat the crap outa it at work. This is called annealing.

So I think if you hot forge your brackets they will probably be softer than the bar was. But its all relative anyway. I would anneal them, after forging, to equalise any stresses. Are you after tensile strength (pulling lengthwise) or compressive strength (load bearing)?

None of this probably helps huh :D Just go ahead and make'em and let us know ;)

A pic or two if you really need some more specific advice. Alternatively, cast them ;)

[ 09-14-2003, 12:45 AM: Message edited by: Big Red ]