Condenser is mainly made of carbon steel, stainless steel and copper. When carbon steel tube plate is used as cooler, corrosion leakage often occurs in the weld between tube plate and tube, and leakage into cooling water system will cause environmental pollution and waste of materials.
In the production of condenser, manual arc welding is generally used for the welding of tubeplate and tube row. There are different degrees of defects in the shape of weld, such as depression, porosity, slag inclusion, etc., and the distribution of weld stress is not uniform. In use, tubesheet part is in contact with industrial cooling water, and impurities, salts, gases and microorganisms in industrial cooling water will constitute corrosion of tubesheet and weld. Studies show that industrial water, whether fresh or seawater, will have a variety of ions and dissolved oxygen, among which the change of chloride ion and oxygen concentration plays an important role in the corrosion shape of metal. In addition, the complexity of metal structure also affects the corrosion morphology. Therefore, the corrosion of tube plate and tube weld is mainly pitting and crevice corrosion. From the outside, there will be a lot of corrosion products and sediment on the surface of the tube plate, and there are different sizes of bubbles. With seawater as the medium, galvanic corrosion can also occur. Bimetal corrosion is also a common phenomenon of tubesheet corrosion.
In view of the condenser anticorrosion problem, western countries mostly adopt the method of polymer composite materials for protection, among which various technical products are more widely used. It has excellent adhesion ability, temperature resistance and chemical corrosion resistance. It can be used safely in a closed environment without shrinkage. In particular, it has good isolation of bimetal corrosion and scouring resistance, which fundamentally reduces the corrosion leakage of the repair part and provides a long-term protective coating for the condenser.