316 contains a minimum 2.0% molybdenum which makes it much more corrosion resistant than 304 however, as it is a more expensive element, generally makes 316 a more expensive grade of metal.

The mechanical properties are identical, both are austenitic, so no issues of concern there. Welding is simple, either 308L or 316L filler metal could be used. However, using 304L components in a 316L piping system is a different story, especially if 304L has a significantly higher corrosion rate than the 316L.