... : 8mm-3000mm, thickness: 0.4-60.0mm2) Square tube: 10 x 10mm-1000 x 1000mm, thickness: 0.6-60.0mm3) Rectangle tube: 15 ... x 10mm-800 x 500mm, thickness: 0.6-60.0mmB: Surface finish: black, blank ... C: Length of each pipe: 500mm-16,000mmD: Steel grade: 10#, 20#, A106B, A53B, Q195 Q235, Q345, ST37-2, ST52, S235 ...