The corrosion of automotive mufflers collected in North America was in
vestigated. Aluminum (Al)-plated steels corroded severely in the subst
rate under the Al plating. Type 409 (UNS S40900) stainless steels sust
ained a large number of pits. The effects of ions in the condensate an
d activated carbon on the corrosion resistance of muffler materials we
re studied with a newly developed condensate corrosion test.