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STAINLESS STEEL · MATERIALS

What Is Marine Grade Stainless Steel?

Marine grade stainless steel usually means grade 316 or 316L: austenitic stainless steel with 2 to 3% molybdenum, which resists pitting from salt water and sea spray far better than 304. It is a trade description rather than a formal standard, so always check the actual grade on the specification.

01

The Short Answer

“Marine grade” is shorthand for stainless steel that copes with a salty environment. In practice that means 316 or its low-carbon version 316L, and for fasteners the equivalent A4 grade. The molybdenum it contains strengthens the passive layer that stops chlorides from pitting the surface.

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    Grades 316 and 316L; A4 for bolts and screws.
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    Key addition 2 to 3% molybdenum.
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    Resists Salt spray, sea air, brine and chlorinated water.
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    Limits It can still tea-stain in crevices and needs rinsing; for warm seawater immersion, duplex grades are often used instead.
02

Marine Grade in Industrial Computing

Computers and displays on deck or near the coast use 316 stainless or sealed aluminium housings with IP66 or better sealing. Our guide to 304 vs 316 stainless steel explains the difference, and our marine panel PCs and marine monitors are designed for shipboard use.