30 
ME. J. EEGINALD ASHAVOETH: 
JMagram Vill. 
Relation of Young’s modulus (Y) and its temperature coefiicient (y) to drawing in piano steel wires. 
areas as abscissae and Young’s modulus as ordinates ; on the same diagram the curve 
of the temperature coefficient of the modulus is plotted, but this will be referred to 
afterwards. 
A feature of this curve is that annealing, hard drawing, and tempering all produce 
an upward effect, which is continued until the last stages are reached, and then a 
decided drop occurs ; thus, again, the initial effects of drawing are reversed by extreme 
traction. The increase of the modulus is very conspicuous when the wire has been 
tempered, the rise at this stage being nearly one half of the whole change, which, 
from least to greatest, is about 21 per cent. On the other hand, drawing between 
the 2nd and 3rd stages has only a small effect on the modulus, and the influence 
of successive cold drawing after tempering for at least two stages is comparatively 
unimportant ; then, after a sharp rise at the 8th and 10th stages, with some 
irregularity at the 9th, there is the rapid fall to the 11th and 12th points. The 
irregularity in the final stages is here apparent, as in some of the other curves, and 
confiims the suspicion that there has probably been some departure from the 
even course of drawing after the 8th stage, as mentioned when the process of 
manufacture was described.'^ It seems not unlikely that it recpiires very skilhd 
manipulation of the material in order to obtain maximum elasticity, and about stages 
(8) to (10) the wire possibly develops a critical condition. 
