THE OUTER DIAMETER AND WITHIN THE DOUBLE COATING, STEEL HAVING AN EPOXY RESIN COATING LAYER THAT COATS THE OUTER DIAMETER AT THE SAME TIME

摘要

The present invention relates to a double coating of an outer diameter and a steel pipe with an epoxy resin coating layer coating inner and outer diameters at the same time. The present invention is made of an epoxy coating layer, an adhesive resin layer, and a poly ethylene coating layer on a metal layer external surface of a steel pipe heated by a heating gear in a heating chamber and turned by a turning gear and an inner diameter epoxy coating layer on an inner surface of the metal layer.