The Fundamentals of Metalworking (PDF)
The Fundamentals of Metalworking (PDF)
The Fundamentals of Metalworking (PDF)
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Determination <strong>of</strong> flow curve<br />
Stress-strain curve<br />
σ<br />
σ ο<br />
ε 2<br />
A<br />
ε 1<br />
Ture stress-strain curve <strong>of</strong> a ductile<br />
metal under uniaxial tensile loading.<br />
ε<br />
σ = Kε n<br />
• Hook’s law is followed up to the yield point, σσσσ o .<br />
σσσσ is ture stress<br />
εεεε is true strain<br />
K is constant<br />
n is work hardening exponent<br />
(this is valid from the beginning <strong>of</strong> plastic<br />
flow to the maximum load at which the<br />
specimen begins to neck down.)<br />
• Beyond σσσσ o , metal deforms plastically (strain hardening).<br />
• Unloading from A immediately decreases the strain from<br />
εεεε 1 to εεεε 2 = σσσσ/E the strain decrease εεεε 1 -εεεε 2 is the recoverable<br />
elastic strain.<br />
Suranaree University <strong>of</strong> Technology Tapany Udomphol<br />
Jan-Mar 2007
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