Stainless steel composite panels, composite pipes
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Stainless steel will corrode when in contact with carbon steel; so how do stainless steel composite sheets and composite pipes prevent such contact corrosion?
When stainless steel comes into contact with carbon steel, it results in galvanic corrosion, that is, corrosion between different metals. In natural conditions, the potential of stainless steel is more positive than that of carbon steel; as a result, carbon steel acts as the anode and gets corroded, functioning like a sacrificial anode. If the carbon steel area is larger than that of stainless steel, it is a large anode, and there is no major problem. Moreover, the stainless steel itself has not corroded; the carbon steel does not come into contact with the medium, so there is no need for a carbon steel sacrificial anode
Corrosion requires conditions. It’s not the case that corrosion occurs whenever stainless steel comes into contact with carbon steel.
I have doubts about the use of stainless steel composite panels. In some structures, the composite layer is removed during welding, leaving only the base layer. My understanding is that when exposed to conductive media, the carbon steel surface adjacent to the stainless steel composite layer will suffer severe corrosion; grooves may even form quickly, which reduces costs but increases risks.