... 1 high tention and good quality 2 black carbon steel pipe manufacture 3 widely use in many ways ... 4 GB,JIS,ISO,ASTM,BS,DIN the black carbon steel pipe is widely use in conveyor belt transmission,machine ... you know the rectangular steel pipe is world wide use in construction,goods shelf,steel sheds,truck manufactruing,road ... sightProductivity20000 ton per monthMOQ10 ton per size black carbon steel pipe