COATING METHOD FOR PIPE HAVING WELD BEAD

摘要

Method of coating pipe having a raised weld bead. Curable resin polymer is applied to the pipe and allowed to bond to form a cured or partially cured polymer layer on the pipe. Powder form adhesive composition is applied on the polymer layer while hot, with fusion into a film bonding to the polymer. Powder form polyolefin is applied on the adhesive while hot with fusion into a film bonding to the adhesive to form a powder-based coating. Following forming of the powder-based coating, the pipe is cooled from the inside. An outer polyolefin covering is bonded to the powder-based coating and the pipe cooled to ambient temperature. This procedure can avoid voids, cavities or pinholes forming in the coating adjacent the weld bead.