The cast iron plate heat exchanger is not easily damaged by corrosion because the cast iron itself has good resistance to oxidation and corrosion, not because of the wall thickness. In recent years, some small domestic manufacturers have tried to solve the corrosion protection problem of steel heat exchangers by increasing the wall thickness, which is completely wrong. Because the corrosion of steel heat exchangers is local corrosion of small holes, rather than uniform corrosion. In recent years, due to the continuous improvement of the heat exchanger manufacturing process, the industry requirements are getting higher and higher. The cast iron heat exchanger will gradually be overcome due to its incompressible disadvantages such as low pressure, heavy volume, rough shape and high energy consumption. The market is eliminated.