... ×1.53-40 Rectangular TubeQ195,Q235,Q345,20#GB/T6278-2002 Structure, decoration, construction20*20-500*500 ductile iron pipe-ironGB/T13295 ... , boilers, drinking water, machinery, military industryDN80-1500-square pipeQ195,Q235,Q345,20#GB/T6278-2002 Structure, decoration, construction20*20- seamless steel pipe for construction