square steel pipe can be used in construction structure ,machinery ,container ,hall structure ,airport structure ,shipbuilding Product:square steel pipeMaterial:Q235,Q345,20 ... thickness between :2-25mmsquare steel pipe can be used in construction structure ,machinery ,container ,hall structure ,airport structure ,shipbuilding500mm*500mm*8mm~25mm ... *160mm*5mm~16mm150mm*150mm*5mm~14mm square steel pipe