Isaac wrote about wire: >I come back with this post that you may not have noticed. It is a >prcocess to produce some sort of annealing on new strings well no, not annealing which is done by heating the wire. The process being used here is a mechanical manipulation. >if you want the strings to sound more brillant, may be they may be >aged (other strings as well) Sounds like cheese or wine-making, not wire-making... I don't like the method for music wire as described. Presumably, the procedure is being applied to raise strings past their elastic limit but below the ultimate tensile strength (uts). This would tend to enhance stability, but only if the working stress on the wire is too close to uts to begin with, either because of bad scaling or bad wire. And the result is a second-rate tonally-poor wire in my view. Isaac, methinks you had a song and dance from your wire-maker friend about this, or at least whoever told the original story is playing fast and loose with the metallurgical facts with a dash of salemanship thrown in. There is some basis in reality but not a good one in my view. The tensile properties of high quality music wire should be: (1) high uts consistent with desired working stress, (2) yield point as close to uts as possible, and (3) sharply defined transition to plastic deformation. It's quite difficult the make wire with all of these properties - modern patented high carbon steel music wire is a marvellous product that is too often taken for granted. If you look at something like Roslau wire you get a yield point of about 2200MPa with UTS of 2400MPa [these values are typical]....yield may begin a bit lower, but the sharp dive is around these typical values. There is no room in that tensile curve for the sort of "conditioning" described, so whoever is doing it is using bad wire to begin with. It is undesirable anyway to stress wire beyond its yield point - this does raise the yield point to some new value closer to UTS, and in fact the deformation is actually almost instantaneous, so there is no need for the hours of sitting of original yield point, if you did want to do this. Why undesirable? Well, in my view, the sort of "brilliance" you could achieve this way is metallic, almost unpleasant - plastically stretched wire is metallurgically quite different from drawn wire. I can see why it might be resorted to in some cases, for instance if the wire product being used is not properly drawn as music wire, and yield point is too low in relation to UTS [but the result will always be second-rate]....this is the problem with all Rose wire for instance. Or I can see it being resorted to because of a bad scale with working stress too close to yield point, but not really a good solution. Better to use better scaling more appropriate to the wire product being used. I can also see it being used as a bandaid solution to fix wire which has a shallow transition to plastic zone from elastic, instead of the desirable sharp transition, as I expect is the case with many subsitute "low tension" wires [although I haven't tested many of these wire types yet]. In all cases it is better to fix the problems at either the design level or the wire product level, rather than tinkering with the mechanical properties of the wire by stretching it. >comments welcome. Hmm. Not sure I said what you were hoping to hear Isaac.... Stephen -- Stephen Birkett Fortepianos Authentic Reproductions of 18th and 19th Century Pianos 464 Winchester Drive Waterloo, Ontario Canada N2T 1K5 tel: 519-885-2228 mailto: sbirkett[at]real.uwaterloo.ca http://real.uwaterloo.ca/~sbirkett
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