Comparative study of the tensile properties of a 1.25Cr-0.5Mo steel characterized by the miniature specimen and the standard specimen

Both of the miniature specimen and the standard round bar specimen were used to measure tensile properties of a 1.25Cr-0.5Mo steel. The elastic modulus, the yield strength and the ultimate tensile strength measured by the above two kinds of specimens were compared with each other. The potential factors which may have influence on the testing results of miniature specimen were discussed. It is found that the strength measured by the miniature specimen is consistent with that measured by the standard specimen. While the elastic modulus obtained by the miniature specimen is significantly lower than that obtained by the standard specimen. The machine compliance should be precisely considered when the elastic strain of miniature specimens is to be measured from the crosshead displacement. The geometry size plays a critical role during the post-necking elongation.