Din black and phosphated hydraulic tube Synopsis of process routing: din highly accurate, cold drawn and bright seamless steel tube is used as the tube to be phosphated. The phosphated is realized with the imported chemical fluid to form a black film. The antirust oil is absorbed by means of the micropore on the film to prevent from the rust. The caps are covered at two ends of tube to prevent from the dust. Main features: color of steel tube: bright black. Color is homogeneously distributed on the tube surface. The tube has good property of antirust. Main application: used in hydraulic system. This tube is our main product for export business.