... 4 GB,JIS,ISO,ASTM,BS,DIN the black carbon steel pipe is widely use in conveyor belt transmission,machine ... is world wide use in construction,goods shelf,steel sheds,truck manufactruing,road construction,fence manufacturing,gate manufacturing,workhop ... is world wide use in construction,goods shelf,steel sheds,truck manufactruing,road construction,fence manufacturing,gate manufacturing,workhop ...