Abstract: A culvert having a corrosion resistant composite coating and a method of producing the corrosion resistant composite coating. The coating method is for use in a coventional hot dip coating line of the type wherein a steel strip, having been appropriately pretreated so as to be at or above the coating temperature and have its surface free of oxides, is caused to pass through a bath of molten coating metal. A fibrous aramid paper is bonded to the surface of the steel strip by pressing the fibers into the molten coating layer immediately after the steel strip exits the coating bath. The steel strip may be fabricated into construction products such as culvert which may be further protected with bituminous type coatings.

Abstract: A culvert having a corrosion resistant composite coating and a method of producing the corrosion resistant composite coating. The coating method is for use in a conventional hot dip coating line of the type wherein a steel strip, having been appropriately pretreated so as to be at or above the coating temperature and have its surface free of oxides, is caused to pass through a bath of molten coating metal. A fibrous aramid paper is bonded to the surface of the steel strip by pressing the fibers into the molten coating layer immediately after the steel strip exits the coating bath. The steel strip may be fabricted into construction products such as culvert which may be further protected with bituminous type coatings.

Abstract: The method of coating an elongated metallic member with a thermosetting plastic powder coating or with a thermosetting plastic powder undercoating and a thermoplastic powder outer coating, is significantly improved by passing the coated elongated metallic member through at least one induction coil to heat the metal and thereby the coating to the curing temperature of the thermosetting plastic powder and holding the temperature for the curing time. Curing temperatures, which depend upon the thermosetting plastic powder coating being cured, are sufficient to fully cure the material within seconds.

Abstract: A power grid for a fluidized bed for electrostatically depositing a powdered plastic coating material from the bed onto an elongated metal substrate moving in a path of travel above the upper surface of the bed on a substantially horizontal pass line. The power grid includes two co-planar wire mesh elements positioned beneath the surface of the bed, the elements having opposed edges in parallel spaced relationship and defining a gap therebetween beneath the pass line. The edges are upturned to form a plurality of electrode segments, the tips of the electrode segments being substantially coincident with the upper surface of the bed when energized. In operation the electrode segments form a row of localized corona discharges to either side of the passing substrate to effect electrostatic deposition of a thin uniform film coating of the powdered material thereon.