Seamless steel pipes used in steel construction. 1) Dimentions: 30*30mm-800*800mm, Thickness: 3-40mm Length ... , shipbuilding, automobile axle pipe and so on.4) Use: construction structure, machinery making, container, hall structure, sun seeker, offshore ... Material: Q235, Q345, 20#, ST37, ST44, ST52, ASTM A53, ASTM A106,STKR4907) Plain or beveled ends Seamless Square Steel Pipe used in construction