What does 18-8/304 stainless steel mean? 18-8 refers to a common stainless steel composition associated with 304 stainless steel. The material provides good corrosion resistance for many construction, fabrication, coastal, and marine applications. By Marsh Fasteners|2026-09-13T05:08:06-04:00September 13, 2026|Stainless Steel Fine Pitch Threaded Rod|