When the heat exchange tube material is S316, why is S316 cladded on the fixed tube sheet?
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There is a fixed-tube-sheet heat exchanger, with a shell-side pressure of 2.6 Mpa and a tube-side pressure of 16 Mpa. The material of the fixed tube sheet is 16MnⅣ forged steel, while the material of the heat exchange tubes is S31603. I would like to ask now: when the fixed tube sheet faces the tube side, that is, on the side where the weld joints between the heat exchange tubes and the fixed tube sheet are located, what is the main purpose of cladding a certain thickness of S31603 on 16MnⅣ?
Cladding S31603 on 16MnⅣ fixed tube sheets is primarily intended to improve the corrosion resistance of the welding area between the tube sheet and the heat exchange tubes, ensure compatibility between the materials of the tube sheet and the tubes, reduce electrochemical corrosion caused by material differences, and extend the service life of the heat exchanger. .
1. Need for corrosion resistance 2. Avoiding welding of different steel types
To improve corrosion resistance, using solid stainless steel forgings is costly; cladding is employed to reduce costs
1. The need for corrosion resistance on the tube sheet side. 2. Avoiding welding of different types of steel (tube sheet and heat exchange tubes). 3. Using this composite structure to reduce costs (stainless steel is expensive and has low strength).
Firstly, all materials in contact with the process medium must be stainless steel. Secondly, if welding is not used, a solid stainless steel tube sheet must be employed, which results in extremely high costs
1. The need for corrosion resistance on the tube sheet side. 2. Avoiding welding of different types of steel (tube sheet and heat exchange tubes). 3. Using this composite structure to reduce costs (stainless steel is expensive and has low strength).
Generally speaking, it is for the purpose of preventing corrosion in the pipeline. Secondly, using carbon steel for the shell side helps save costs
The pipe lining needs to be stainless steel for corrosion resistance.