Steel Tensile Testing Calculation Sheet

Steel Tensile Testing Calculation Sheet UTK Governor’s School June 2013

The following calculations need to be performed on annealed and cold-rolled 1045 carbon steel tensile data:

. Calculate engineering stress, s, and engineering strain, e, for each data point of load,

P, and extension, x. is the initial gage length and is the initial cross-sectional area of the specimen.

. Identify the ultimate tensile strength (UTS) and failure strain from a plot of engineering strain versus engineering stress. Using the failure strain, compare the ductility of both steels.

. Calculate true stress, and true strain, for each data point of engineering stress and engineering strain up to the point of necking (i.e. the maximum load).

For the cold rolled steel tensile data: . Calculate the elastic modulus, E, from a linear fit to the data prior to the onset of plasticity.

. Calculate the 0.2% offset yield strength, . is the load that corresponds to the 0.2% offset. In other words, is the load necessary to plastically deform the specimen so that L is 0.2% longer than .

. Finally, calculate the work hardening exponent, n, from a power law fit to the data from the 0.2% offset yield strength to the point of necking (i.e. the maximum load). K is the strength coefficient. For the annealed steel tensile data:

. Calculate the elastic modulus, E, from a linear fit to the data prior to the onset of plasticity.

. Identify the yield strength as the point at which the stress drops.

. Calculate the work hardening exponent from a power law fit to the data from the point at which stress begins to increase after the yield drop to the point where necking begins (i.e., the maximum load).