Thick steel plates are widely used in high-rise buildings and large-span steel structures.However,the increase of steel plate thickness will induce variations of mechanical properties of steel plates,especially the thickness properties.The mechanical properties of structural steel Q345B with plate thickness from 60 to 150 mm were tested at low temperature through round bar tensile specimens which included two types,i.e.transverse specimen that is perpendicular to the rolling direction and Z-direction(or thr...