... Square steel pipeSpecification: 30-800mm thickness: 3-40mm material: Q235, Q345, 20#, ST44,ST52, STKR490, ASTM A500 Standards:GB,DIN,JIS1 ... *30mm-800*800mm, Thickness: 3-40mm Length: <13m2) Material: Q235, Q345, 20#, ST37, ST44, ST52, ASTM A53, ASTM A106,STKR4903) Standards ...