Um, well, thats how a goldsmith would work with it is by heating it.
I didnt realize its melting temp was quite that high, i was pretty sure you could melt it on a stove top - maybe im thinking 24kt gold, and 18kt has enough stuff added that its not as much of a problem.
You can't reduce hardness, its a property of the material. Nor do i think scratching it is what you are concerned about. I dont think you'll effect the strength of the material, especially at relatively small fractions of the melting temp.
The number I reported was for pure gold. "18kt yellow gold melts typically at 895-930C" according to one site, which is similar to that of pure gold.
I expect that 18K gold metal has various different metal phases. Heating and (super)cooling the metal can change which phase it is in, and it's commensurate properties. I could be wrong about the different phases, though.
The Au-Sn phase diagram shows several different states. The solid colors are pure states, and the lines are combination of states. The Au-Ag diagram unfortunately doesn't go low enough to be of interest.
My guess from those by extrapolation is that heating on the order we're talking about isnt likely to change anything. I mean, most of the variation is due to differing percentages of the two metals in many of the cases, or on really high temperatures. I doubt any temperature Mary would be willing to work with it at would be a problem.
no subject
Date: 2005-01-13 08:55 am (UTC)I didnt realize its melting temp was quite that high, i was pretty sure you could melt it on a stove top - maybe im thinking 24kt gold, and 18kt has enough stuff added that its not as much of a problem.
You can't reduce hardness, its a property of the material. Nor do i think scratching it is what you are concerned about. I dont think you'll effect the strength of the material, especially at relatively small fractions of the melting temp.
no subject
Date: 2005-01-13 11:59 am (UTC)I expect that 18K gold metal has various different metal phases. Heating and (super)cooling the metal can change which phase it is in, and it's commensurate properties. I could be wrong about the different phases, though.
no subject
Date: 2005-01-13 12:05 pm (UTC)http://pruffle.mit.edu/3.00/Lecture_36_web/node1.html
The Au-Sn phase diagram shows several different states. The solid colors are pure states, and the lines are combination of states. The Au-Ag diagram unfortunately doesn't go low enough to be of interest.
no subject
Date: 2005-01-13 07:04 pm (UTC)