Sufficient data should be collected to permit the effects of these treatments to be evaluated. Issues that should be considered include:

The uniformity of the initial hardness across the sample, and the uniformity of hardness changes produced by heat treatment.

The effect of the time spent at high temperature on the results of quenching or slow cooling experiments.

The cause of differences produced by quenching in water, oil, or by cooling in air from the same initial conditions.

The effects of reheating quenched or air cooled samples to temperatures lower than the eutectoid temperature, and the dependence of the final properties on the temperature history of the reheating process and the final cooling to room temperature.