n-Value

The strain hardening exponent n is a measure of the response of metallic materials after cold working. After metals have reached their elastic limit and plastically deform they experience strain hardening, which can increase the strength within the final products application. The strain hardening exponent is the slope of the plastic portion of the test after yield and before its ultimate tensile strength. Metals with a high-strain hardening exponent will achieve increasing strength with a small amount of axial strain, whereas a material with a low-strain hardening exponent will experience high axial strain with little increase in strength. To determine n-value automatically, the axial strain needs to be accurately measured using an extensometer.