Yes, 430 is stainless, but at much lower levels of nickel and chrome. To the point where it becomes magnetic. 430 will rust when exposed to salt and moisture but at slower rates than mild steel. Several years ago, when SS exhausts first started appearing as OEM systems, automotive marketing started advertising the "big deal" with having SS exhausts as standard. And very slowly they would start to rust....... But they were made out of stainless. The better systems are made from 304 stainless (more nickel and chrome) and you can easily tell because a magnet won't stick.
