We are a leading Manufacturer, Supplier and Exporter of the finest Water Cooled Piercing Plug. We use a CrNi low alloy steel as a plug material of the tool for piercing or rolling. In order to obtain heat insulating effects and lubricating effects in the piercing before using the plug, a heat treatment is performed to the plug in an oxidizing atmosphere to form an oxide film on a surface of the plug. The thickness of the oxide film is mainly composed of iron oxide. Elements such as W, Mo, Nb, Ti, and Nb are added to the CrNi low alloy steel in order to form the oxide film which has excellent adhesion to the base metal.