Estimating Ultimate Shear Strength from Ultimate Tensile Strength of Aluminum and its Alloys for Blanking or Piercing

Abstract

In pressworking, large forces cut or deform a material, and specific shearing processes include blanking and piercing of metals, including aluminum. The force requirement is directly proportional to the ultimate shear strength, USS, of the sheared material. Nevertheless, shear strengths are not readily found in engineering references, especially for the multitude of aluminum grades and tempers. Thus, USS is often estimated from some percentage of the ultimate tensile strength. However, analyses for these estimates are lacking, and it is not clear how accurately the USS is predicted. In this review of 197 aluminum alloy data, it is shown that 60% of the ultimate tensile strength provides a satisfactory estimation for USS as the predicted shear strength is, on average, within 5.5% of the actual value. USS of weaker grades, as well as for all annealed material, tends to be underestimated while the strongest grades are overestimated. The availability of reliable aluminum shear strength data makes for more efficient pressworking.