What Is 316L Stainless Steel? Why Watch Brands Use It
If you've shopped for a quality watch, you've seen the designation 316L stainless steel in the specifications. Most brands list it. Few explain what it actually means, or why it matters for the person wearing the watch. Here's the full picture.
What Does 316L Mean?
316L is a specific grade of austenitic stainless steel. The "316" refers to its alloy composition, which includes iron, chromium (16–18%), nickel (10–14%), and a small percentage of molybdenum. The "L" stands for low carbon keeping carbon content below 0.03%, which improves corrosion resistance and makes the steel easier to weld without losing its protective properties.
It's also commonly called "marine grade" stainless steel because it performs well in saltwater environments where standard stainless steel would corrode. The same grade is used in surgical implants, food processing equipment, and pharmaceutical manufacturing industries where material integrity is critical.
Why Is It Used in Watches?
Four reasons:
Corrosion resistance: 316L resists rust, tarnishing, and oxidation significantly better than standard steel grades. A watch case made from 316L holds its surface and colour through years of sweat, rain, and occasional water exposure without degrading.
Hypoallergenic properties: The nickel in standard steel grades can trigger reactions in people with nickel sensitivity. The specific composition of 316L, combined with its dense surface structure, significantly reduces nickel migration making it safe for sensitive skin and extended daily wear.
Durability: 316L maintains its structural integrity under the mechanical stresses involved in watch manufacturing case pressing, case back threading, lug drilling without cracking or deforming. It also resists surface wear better than softer metals.
Finish quality: 316L takes polishing, brushing, and frosted surface treatments extremely well. It holds fine surface detail without the treatment degrading quickly under wear which is why luxury watchmakers at all price points specify it.
316L vs Other Metals in Watchmaking
Standard stainless steel (304): Less corrosion-resistant, more prone to tarnishing in marine environments. Common in budget watches. Noticeably inferior for long-term wear.
Titanium: Lighter than steel, highly corrosion-resistant, and biocompatible. More expensive to machine. Used in higher-end sports watches where weight reduction is a priority.
Gold plating over steel: A base of steel (often lower grade) with a surface layer of gold. The plating wears off over time with daily use, revealing the base metal underneath. Cosmetically gold but not structurally.
Solid gold: Soft, heavy, expensive, and far beyond the price range of most everyday watches.
What to Look for When Brands Claim Stainless Steel
Not all stainless steel is 316L. Some manufacturers use 304 or lower grades and list them simply as "stainless steel" without the grade specification. If a brand is using 316L, they will name it specifically because it's a genuine differentiator worth communicating.
At Tomell London, 316L stainless steel is the standard across our watch collection the same alloy used in medical implants and marine applications, chosen because a watch you wear every day deserves the same material standards.