Influence of Tensile Specimen Width on Yield Strength Ratio Testing Results of X65 Pipeline Steel

Through comparing the tensile testing results of 10 groups of specimens of X65 pipeline steel with different width, the influence and reason of specimen width on the yield strength ratio were analyzed. The results show that the yield strength ratios of the wider specimens were generally higher than those of the narrower specimens, and the root cause lied in the interior microstructure nonuniformity of the material. Therefore, when testing the tensile properties of pipeline steel, a unified specimen width should be obeyed strictly according to the product specification, to insure the tensile testing results in different laboratories have comparability.