... -5mm 4) quality:Q195, Q235,Q345 Black pipe processing cycle: Hot Dipped Galvanized Pipe Proceed FlowBlack Pipe Examination→Acid Washing→Water Washing→Solvent Coating ... ,precision machines,petro-chemical ,ship,structure pipe,automobile,shock absorber,building,geology,fluid tubes,line pipe etc4.High quality:ISO9001 API5L API5CT ...