Laser cladding technology to small diameter pipes

A laser cladding method which produces a highly corrosion-resistant materia l coating layers (cladding) on the austenitic stainless steel (Type 304 SS) pipe inner surface was developed to prevent SCC (stress corrosion cracking ) occurrence. This technology is applicable to a narrow and long distance a rea from operators, because of the good accessibility of the YAG (Yttrium-A luminum-Garnet) laser beam that can be transmitted through an optical fiber . In this method a mixed paste metallic powder and heating-resistive organi c solvent are firstly placed on the inner surface of a small pipe, and then a YAG laser beam transmitted through an optical fiber irradiates to the pa sted area. A mixed paste will be melted and form a cladding layer subsequen tly. A cladding layer shows as excellent corrosion resistance property. Thi s laser cladding (LC) method had already applied to several domestic nuclea r power plants and had obtained a good reputation. This report introduces t he outline of laser cladding technology, the developed equipment for practi cal application in the field, and the circumstance in-actual plant applicat ion. (C) 2000 Published by Elsevier Science S.A. All rights reserved.