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Heat-harden Brass?
tantoinette -
Friday, November 21, 2008 - 7:24pm
brass | harden | heat treating I am wondering if brass can be heat-hardened. I've made a brass cuff that is a bit too flimsy, and would like to harden it without changing the surface. I've already tried tumbling with steel shot for about 5 hours, but it did not seem to harden it at all. Any suggestions/ideas? I've searched the web and ganoksin, and the answer seems to elude me.  If you heat brass to
marilyn -
Saturday, November 22, 2008 - 10:27am
If you heat brass to soldering or annealing temperature and quench it, it is hardened. To keep it malleable, it needs to air cool. marilyn  I hate to disagree with you
jbin -
Saturday, November 22, 2008 - 4:28pm
I hate to disagree with you Marilyn but unless she is working with Muntz metal(60Cu/40Zn) heat treatment is limited to annealing. Cold work is the only way to harden it, any heating will only soften it. Jim  Sorry, there is no way to
Rich Waugh -
Saturday, November 22, 2008 - 6:18pm
Sorry, there is no way to harden brass by heating it. Any heating above a low red heat will only anneal it. The faster you cool it down from hot, the more completely it anneals. To harden brass it must be work-hardened. Your thought of shot-peening it was a good one, but unfortunately inadequate. To achieve work-hardening, the metal must be deformed more than just at the surface, and the tumbilng with shot will not do that. It's going to take a hammer, or some other method that compresses the metal to harden it. The greater the compression, the greater the hardness; right up to the point where it breaks because the elastic limit has been exceeded. Since you don't want to change the surface, all I can suggeest is that perhaps you could line the inside with a layer of brass that has been work hardened. Perhaps use countersunk rivets to connect the two layers so you don't lose the hardness to soldering heat. Hi Rich, "The faster you
jbin -
Saturday, November 22, 2008 - 8:39pm
Hi Rich, "The faster you cool it down from hot, the more completely it anneals." This is only true for alloys that have a tendency to precipitation harden (like sterling silver) or form intermetallic phases (red gold, some white golds). With yellow brass it will make no difference how fast you cool it. Air cool or water quench it will be the same hardness as long as the cold working and annealing process was the same. The degree of annealing is dependent on how much cold work was done before annealing , how hot the annealing temperature was and how long it was held at temperature. Jim  Hi,
visitor -
Thursday, June 11, 2009 - 4:53am
I am a high school student doing ' Engineering studies'. one of our assignments were to heat brass to red heat and then quickly quench it in water. The metal was a lot softer than i started off with. the change was very clearly noticable. as i was easly able to bend the brass after the hardening treatment. In one sentence heating to red heat and the quenching brass only makes it softer. We also had to work harden the sample after hardening. we used a hammer and struck the brass continuously for about 10 mins. the brass was a lot harder. id be careful though one of my mates ended up snapping his piece doing this. Thank you!
visitor -
Thursday, April 14, 2011 - 7:40am
Its great to hear that High School students learn this stuff and that at least one is willing to pass on what they have learned. Im proud of you for doing that! Great work! |
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ArtMetal
Most brass will not heat
Most brass will not heat harden. There are some exceptions (Muntz Metal is one) but they are specialty alloys that are not typically available to the casual purchaser and are certainly not the brass that is supplied by most small quantity suppliers which is Yellow Brass.
JB