Carbon steel tube 1)OD:4mm-50mm; WT: 0.5mm-5mm 2)good quality and competitive price 3)for construction and steel structual -product ... , industrial dilivery(gas,water,oil)60-630×1.53-40 Rectangular TubeQ195,Q235,Q345,20#GB/T6278-2002 Structure, decoration, construction20 ... ,Q235,Q345,20#GB/T6278-2002 Structure, decoration, construction20*20- steel tube for construction