Strictly speaking, 304 stainless steel pipe and carbon steel pipe can not be piled together, because the raw materials of carbon steel pipe and stainless steel pipe are not the same, in a humid environment, if the carbon steel pipe and stainless steel pipe are piled together, it is simple to chemical reaction, and then damage the protective layer of stainless steel pipe, resulting in rust of stainless steel pipe.
Different steels piled together in contact with each other will have a potential difference, and then lead to electrochemical corrosion, especially when there is water, the electrochemical corrosion speed between stainless steel pipes and carbon steel pipes will accelerate.
Just like the battery principle, the direct conversion of chemical energy into electrical energy in a chemical battery is due to the oxidation recovery reaction that takes place inside the battery. In order to prevent electrochemical corrosion and carburizing of stainless steel pipes, it is best not to pile up between the two. However, at room temperature, when carbon steel and stainless steel contact carburizing will not immediately occur, and the colorful rust on the stainless steel pipe will appear for a certain period.