Hollow Section 1.Grade:Q235 Q345 A36 A53 16Mn ST37 20#, etc 2.Sized:10*5-90*60mm 3.Wall Thickness:0.8-7mm 4.Length:5.8-12m Basic Information:Rectangular hollow section is a kind of hollow rectangular thin wall steel pipe. The steel strip welded round pipe and then rolled into the rectangular pipe. StandedAISI, ASTM, BS, DIN, GB, JIS, etcGradeQ235, Q345, 20#, 45#, 16Mn, ST37, ST44,ST52, A53, A106, ...