316L stainless steel is very robust and therefore a popular material for watch cases. The advantages have also convinced us, which is why we use this stainless steel for the casing of all our Circula watches, which is also known as surgical steel. In this article we will take a closer look at 316L stainless steel and its use in watches.

What is 316L stainless steel?

316L stainless steel is a corrosion-resistant, iron-based alloy. In addition to iron, surgical steel essentially contains:

  • 16,5 to 18,5 % chromium,
  • 10 to 13 % nickel and
  • 2 to 2,5 % molybdenum.

Circula SuperSport with 316L stainless steel case

316L stainless steel also contains small amounts of other elements, e.g. phosphorus (0.045%), sulfur (0.015%) and nitrogen (0.11%). The chromium makes the steel particularly corrosion-resistant (“Stainless Steel”), nickel increases the resistance to acids and the small amount of the alloy element molybdenum increases the strength, corrosion and heat resistance even further.

316L stainless steel: perfect for watches!

The special chemical composition of the 316L stainless steel alloy makes the material robust and corrosion-resistant. Especially for watches that are worn a lot and can e.g. come into contact with salt or chlorine water, this is an advantage. 316L stainless steel survives the contact undamaged and, with the appropriate water-resistance, watches with a surgical steel case like the Circula AquaSport II or SuperSport can also be worn when swimming and diving in the swimming pool or the sea.

Other advantages of 316L stainless steel for watches:

  • Bare, glossy surface (titanium, for example, looks significantly greyier and matt in comparison)
  • 316L stainless steel is colorfast. If the stainless steel looks discolored, it is dirt that can be removed with a dry cloth.
  • 316L stainless steel is easy to coat so that the watch case does not always have to be silver-colored. We have coated some of our Circula watches with rose gold using the PVD process.

Circula AquaSport II Automatic with 316L stainless steel case and bracelet

316L stainless steel and nickel

In contrast to other stainless steels, surgical steel is anti-allergenic and therefore also suitable for allergy sufferers. In addition to the robustness, this is another reason why we use 316L stainless steel for the cases and steel bracelets of our Circula watches. Surgical steel contains a small amount of nickel, but according to the directive 2014/84/EU https://eur-lex.europa.eu/legal-content/DE/TXT/?uri=OJ:JOL_2014_192_R_0009 regarding nickel, when stainless steel is used close to the body, only a negligible amount of nickel can be released to the skin per week. Special nickel tests from the pharmacy can be used to test whether this amount is being observed.

We also subjected our watches to this test and of course all models passed it.


⌀ 40 mm