co extruded polymer layer 80 is applied to the sheet metal 11 at an elevated temperature of approximately 425 u00b0 to 630 u00b0 f and is pressed tightly thereupon by way of a conventional roller 316 subsequently the sheet metal 11 having the co extruded polymer layer 80 applied thereto is cooled 84 and subsequently recoiled 85 for later use in the pipe fabrication process in the preferred embodiment it is contemplated that the pre treatment process is facilitated on both the upper and lower surfaces of the sheet metal 11 with the lower surface treatment providing additional corrosion protection for the soil side of the resultant pipe however the lower side may alternatively be coated with conventional thermoplastic films such as vinyls or acrylics referring now to fig4 and 5 and 11 through 13 the additional process steps of actually forming the metal pipe 10 and applying the integrally formed liner 16 of the present invention are illustrated as shown the pre treated sheet metal 11 previously disposed in a coil 30 is mounted upon a conventional uncoiler 20 the uncoiler 20 facilitates the uncoiling of the pre treated sheet metal 11 having the polymer adhesive layer 80 disposed upon the upper surface thereof the pre treated sheet metal 11 passes.