I've used SS nuts on carbon steel studs over the past 4-1/2 decades of car exhaust wrenching, and have yet to encounter a single example of one seizing to the other.
As I said earlier ... Don't overthink this.
DM
__________________
2000 Ocean Blue Boxster S
1980 Ferrari 308 GTSi
2019 Alfa Romeo Giulia Ti Sport AWD
|