... We are HuZhou ARO METAL CO.,LTD,we produce annealed square steel tube.If anything we can help you,pls contact me ... directly and feel free. square steel pipe/tube(Hot finished) Size: 80x80mm-500x500mm Thickness: 4mm-20mm ... depends on size Standard: EN10219,EN10210,ASTMA500 Steel grade: S235JR-S355J2H ,Q235,Q345 Use: construction structure, machinery, ...