Manufacturing and Improvement of Polyurethane Sprayed Cast Iron Pipe Fittings
Ductile cast iron pipe fittings made of polyurethane spray.Transport through the sea climate after a certain time,low probability bubbles and delamination occurred on the surface of the polyurethane coating during the early delivery of products to the des-tination.The manufacturer analyzed the causes and made improvements.The following improvement measures were as follows:l)Focu-sing on the supervision of water removal using high temperature before spraying of blank parts to ensure that water was removed after each fitting water pressure test;2)The padding transporting to blank parts was wrapped with film sleepers to prevent or reduce the chance of oil contact;3)Minimizing the use of manual repair materials in the blank processing unless it was inconvenient to repair local small defects after welding repair and grinding;4)After the blank parts were scraped with manual material,the spraying should be com-pleted within 12 hours.If the surface was unqualified after the completion of a one-time spraying,it needed to be re-sprayed after treat-ment on the production line.It is forbidden to spray twice after a one-time spraying solution;5)Draining the solvent before spraying to ensure that the spray A+B material was mixed evenly and the discharging solvent could not be splashed on the substrate to be sprayed;6)When spraying on one surface,the other surface was protected effectively to prevent the spray flying to form dots or local solidifica-tion;7)High temperature verification.Baking object:fittings after spraying.Process parameters:Baking temperature 80 ℃～100 ℃,baking time 120 mis;8)Special quality personnel supervised the process and confirmed one by one step with signature as improving the process.Finally,there were no bubbles and delamination of products on the destination.
polyurethane A+B two-componenttechnological processbubbles and delaminationanalysis and improvement
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