carbon steel square tube size:15*15mm-1000*1000mm thickness:0.5-30mm ... JISG3466,ASTM-A53.BS1387,JIS-G3444,GB/T3091-2001 Material 20#,Q195,Q235,Q345,St 52,St 37,St 44,S355 ... 2.0-30mm. Our products range includes cold formed square pipe, hot rolled square pipe, cold –formed special section pipe, opening- ... high accuracy and variety types of our products. carbon steel square tube / carbon steel square tube