... in many ways 4 GB,JIS,ISO,ASTM,BS,DIN the black carbon steel pipe is widely use in conveyor belt transmission ... ,road construction,fence manufacturing,gate manufacturing,workhop manufacturing etc. the roller pipe is widely use in conveyor belt transmission,machine ... ,Q235 Q460 Q345 and so on Surfacelightly oil , include black, bright and pre-galvanized End cleanThickness toleranceto your standard or ...