On Tuesday 02 August 2016 16:35:58 Peter Blodow wrote: > Heat treating means applying heat to whatever material on earth. > Hardening is one aspect of it, annealing another, softening or making > malleable yet another. It is not to be expected hat all materials > behave the same. > Everyone knows that brass and other copper alloys harden by mechanical > stress and soften by heating. Just try to straighten a copper wire by > bending. Ferrous metals act different because of their crystal > structure, changing from martensic to austenic (that right in > English?) and back, which copper alloys don't have. > > Peter > I forget which is which, but I believe the point at which the ferrous alloy becomes austenitic, eg non magnetic, is the "curie" temperature for that alloy. One might want to google & check that.
Weller, back in the '50's brought out a soldering iron whose temperature was regulated by a magnet on the end of a wire that set so when cold, it was attracted to the button of steel on the back of the irons interchangeable tip, but when it got to the curie poiint of that button, the magnet let go and opened the switch. And you could buy the tips in 50F increments from 400F to 900F. I have one of the original ones, still works fine with at least 100k running hours on the heater. Steel in the austenitic state can be quenched quickly enough to remain in the austenitic state. FOMOCO did that to their exhaust valves for a couple decades starting with the first OHV V8 in the 54 or maybe 53 model year. Might still be doing it but I haven't tried to stick a magnet on one in 40 years. Technically, when in that state, its a supercooled liquid, and has dimensional instability to match, which is why, since GM had the patents on hydraulic tappets yet from their work on the caddy V12 and V16's in the middle 30's, the exhaust valves warm clearance was 26 to 28 thou. > Am 02.08.2016 20:00, schrieb Mark: > > On 08/02/2016 01:40 PM, Stephen Dubovsky wrote: > >> On Tue, Aug 2, 2016 at 10:46 AM, Mark <[email protected]> wrote: > >>> You can't "heat treat" brass/bronze/copper etc (non-ferrous) to > >>> harden. You can only anneal those metals. They do, however, work > >>> harden, which annealing takes away. > >>> > >>> Mark > >> > >> FWIW, There are copper alloys that can be heat treated. Beryllium > >> copper is one example. > > > > That is kind of atypical though for most non-ferrous metals and > > alloys. I always treated heat treating and annealing as two separate > > processes, the former typically hardening the metal, and the latter > > making it softer. That's how I learned it way back when, but > > perhaps the definition should be expanded. > > > > Mark > > > > -------------------------------------------------------------------- > >---------- _______________________________________________ > > Emc-users mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users > > --- > Diese E-Mail wurde von Avast Antivirus-Software auf Viren geprüft. > https://www.avast.com/antivirus > > > ---------------------------------------------------------------------- >-------- _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
