carbon steel outfitted with stainless steel bolts what will the react 2

[plantoperator]

i have steel gaurds on screw pumps. if i add stainless will it  rust faster.

 

[Surin]

If there is no insulator between the structure and the bolt, you have a classical case of galvanic corrosion. You have carbon steel as anode, stainless steel as cathode, you have electrical path between the two and you&nbsp;&nbsp;have atmosphere with moisture or your environment as electrolyte. This satisfies the 4 conditions&nbsp;&nbsp;for galvanic corrosion. Stainless steel will be cathode, you carbon steel will&nbsp;&nbsp;be anode and will be corroded away. How fast the corrosion rate will depend on the environment.&nbsp;&nbsp;This case is not as bad as the case where you have stainless steel structure and carbon steel bolt. In this case your carbon steel bolt will corrode away in no time due to the fact that you have a large area of cathode and small area of anode. The rule of thumb is that the larger the cathode area as compared to to anode area,&nbsp;&nbsp;the faster the corrosion rate.<br><br>Surin