... coat,bitumen layer 4.Pull strength: >420MPa Ductile iron pipe Material:Ductile iron Rizhao Zhufu Industry Co., Ltd. is manufacturer which ... produce water-cooled centrifugal ductile cast iron pipes according to ISO2531/EN545/EN598 in China. (1) ... for easy connection.(7) High strength,lighter than gray iron,good corrosion resistance,small flow resistance,easy fixing,long life ...