Q: I’m trying to figure out if Duplex stainless steel bolts will gall with 304 stainless?
A: The more dissimilar the materials are the less likely they are to gall and bind together. In the case of 304 SS and Duplex stainless steel, the hardness of 304 is typically around a Brinell of 175. While the Brinell hardness of Duplex 2205 bolts are around 290. The different hardnesses between the materials will help to minimize the chances of galling.