Answer:
Initial radius of cylindrical specimen
ri = 15.46mm
Step-by-step explanation:
Cw = [(A1 - A2)/A1] * 100% ...equation 1
Where CW = cold worked percentage gain for( 27% EL) ductile
A2 = final area of cylindrical specimen = pai * r²
Where r = final radius of cylindrical specimen
So therefore expanding equation 1 will give
A1 * Cw = (100 * A1) - (100 * A2)
Cw = 18% from attached graph
A2 = area of cylindrical specimen after cold work = pai * 14² = 615.75mm²
So therefore
18A1 = 100A1 - (100 * 615.75)
-82A1 = -61575.22
A1 = 750.92mm²
So solving for initial radius from initial area of specimen
r1 = (A1/pai)^½
r1 = (750.92/pai)^½
r1= 15.46mm