Things to note when welding two different metal pipes together

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Example: A thin-walled stainless steel pipe is used to transport highly corrosive solutions. Since the pipe needs to be heated, a carbon steel jacket is placed around it, and it is welded to the stainless steel pipe using stainless steel welding rods of the same material. After short use, leakage occurred at the weld between the carbon steel jacket and the stainless steel pipe. Comment: During welding, stainless steel and carbon steel merge together, and the stainless steel is diluted by the carbon steel. In the stainless steel pipes at the welded areas, the contents of the alloying elements chromium and nickel decrease, resulting in a level that is insufficient to maintain the corrosion resistance required in the operating environment. This leads to an **increased corrosion rate, which causes perforation and leakage. Therefore, when welding stainless steel thin-walled pipes to carbon steel pipes, a stainless steel gasket plate should be used as a transition to prevent the stainless steel pipe from being diluted.