DOUBLE LAYER COATING METHOD OF STAINESS STEEL PIPE

摘要

The present invention relates to a double coating method for stainless water pipe and a double coated stainless water pipe, which is capable of protecting the stainless water pipe from various types of corrosion which occurs when the stainless water pipe is laid underground with a polyurethane coating layer for doubly coating the outer surface of a mostly small-diameter stainless water pipe to obtain corrosion resistance capable of significantly extending the life of the stainless water pipe, and of forming the polyurethane coating layer on a predetermined length of stainless water pipe with a continuous working process. In other words, the double coating method for stainless water pipe of the present invention comprises: a water pipe connecting step for connecting small-diameter stainless water pipes in a longitudinal direction and identifying the coating portions of connection portions; a pre-processing step for removing foreign substances on the surface of the water pipe and forming scratches thereon while transferring the water pipe; a heating step for instantaneously heating the water pipe while the water pipe passes through a high frequency heating furnace; a double coating step for performing polyethylene coating by which the outer surface of the water pipe is coated with adhesive by a first coating unit and with a polyethylene coating solution by a second coating unit; a cooling step for primarily cooling the water pipe by spraying air at a room temperature and secondarily cooling the water pipe by spraying fine water particles; a connecting member separating step for separating connecting members at both ends of the water pipe; and a finishing step for removing coating portions at both ends of the water pipe. [Reference numerals] (S1) Water pipe connecting step; (S2) Water pipe preprocessing step; (S3) Water pipe heating step; (S4) water pipe outer surface dual-coating step; (S5) Water pipe cooling step; (S6) Water pipe connection member separating step; (S7) Water pipe finishing step