... square hollow section: Material: Q195, Q215, Q235, Q345B, X42, Gr. B supplying square hollow section:hollow section, good quallity and attractive price 1.Item: hollow section2. ... -400*400mm, WT: 0.6mm-12mm 1. Commodity specificationsSquare hollow section2. Process methodCold drown, high frequency welded3. MaterialQ195---Q2354. ... within 30 days after the order signed supplying square hollow section