On the tensile strength and hardness relation for metals

A method for predicting the ultimate tensile strength (Su) of a material from Brinell-type hardness tests is described for several metals including steel, aluminum, and copper alloys. The prediction of Su is based on a consistent relationship between Su and a material’s hardness coefficient, Kd. A simple experimental procedure for determining Kd from indentation-hardness test data is presented. The relationship between Su and Kd is found to be 1/3 for all cubic metals. Comparisons between predicted and experimentally determined values of Su are made for each of the materials studied, and sources of error between the two Su values are discussed.