About 316 "Marine Grade" Stainless Steel

If a job requires greater corrosion resistance than grade 304 can provide, grade 316 is the 'next step up'. Grade 316 has virtually the same mechanical, physical and fabrication characteristics as 304 with better corrosion resistance, particularly to pitting corrosion in chemical environments. Grade 316 (UNS S31600) is the second most popular grade in the stainless steel family. It accounts for about 20% of all stainless steel produced.

Like 304, it is an austenitic grade, with the addition of 2–3% molybdenum which further improves corrosion resistance. It is often referred to as a marine grade stainless steel because of its effective resistance to chloride corrosion in comparison to other stainless steel grades.

Grade 316L, the low carbon version of 316, is highly resistant to sensitisation (grain boundary carbide precipitation) and so is extensively used in heavy gauge welded components (about 5 mm and over). Grade 316H, with its higher carbon content has some application at elevated temperatures, as does stabilised grade 316Ti. Nitrogen-strengthened versions also exist as 316N and 316LN.

Characteristics

316 grade steels are known for their excellent welding and forming properties. Less electrically and thermally conductive than carbon steel and is essentially non-magnetic. Grade 316 will require post-weld annealing to promote maximum corrosion resistance, though this is not necessary if Type 316L is used.

Applications

Food and pharmaceutical processing equipment, marine exterior trim, surgical implants, and industrial equipment that handles the corrosive process chemicals used to produce inks, rayons, photographic chemicals, paper, textiles, bleaches, and rubber.

Technical Specifications

The general minimum mechanical properties of 316 Stainless Steel are tabulated below.