HEAT EXCHANGER

PURPOSE:To prevent the corrosion of the joint between a tubular plate and a cooling tube by a method in which a beveled groove is provided around the fitting hole of the cooling tube on the cooling water side of the tubular plate, the end of the cooling tube is projected from the surface of the tubular plate, and a paint is coated on the galvanic corrosion area of the tubular plate around the cooling tube. CONSTITUTION:A beveling M of 1C or more is applied to the fitting hole of a cooling tube 2 on the cooling water side of a tubular plate 1, and the tube 2 is fixed to an expanded tube. A tar-epoxy paint 5 is coated on the galvanic corrosion area of the periphery of the tube 2. The coating area is present inside from 2mm. or more from the outer surface of the tube 2, preferably ranging 0.3% or less of the water contact portion of the tubular plate. To avoid the blocking of the inlet of the tube 2 by corrosion products and also to prevent the intrusion of the corrosion products into the tube 2, the tip of the tube 2 is projected by several mm. or more (preferably 3-10mm. in l) from the plate 1.