316L steel: What are its specificities?
Looking for a steel watch? Charlie Paris offers you French watches with steel bracelets and for all of our watch cases we use 316L steel, a steel that resists corrosion. But what is 316L steel? What are its characteristics ? In this article, Team Charlie Paris will present 316L steel to you and its characteristics.
316L Steel, Stainless Steel, Steel, what are the differences?
Steel is a metal alloy consisting mainly of iron but also of carbon. Carbon added between 0.02% and 2% transforms iron into steel and makes it even stronger but also gives it a certain “flexibility”, which is why steel is widely used for construction. At this stage steel (and 316L steel) is not a stainless alloy. Above 3% carbon, iron becomes cast iron but this large quantity of carbon makes this metal very hard but also brittle.
- Steel, an oxidizable alloy: Raw steel is an oxidizable alloy. It will naturally bind with oxygen molecules present in the air or water through redox reactions. This reaction is more commonly called “corrosion”. These reactions result in the appearance of iron oxide and hydroxide, also called rust, this famous orange-red substance found on certain iron structures. Rust is a destructive agent that gradually consumes steel until it completely decomposes.
- From steel to stainless steel: Strauss and Maurer, two German chemists filed a patent in 1912 to exploit the first stainless steel, a clever mixture of steel and chromium (the discovery of which dating from 1797 is attributed to the French Nicolas Louis Vauquelin) and nickel (discovered in 1751 by Axel Frederik Cronstedt), which makes the steel very resistant to corrosion and prevents it from rusting. Chromium content of stainless steel is at least 10.5%, its Carbon content must be less than 1.2% and its Nickel content around 8%. There are 3 categories of stainless steel: ferritic, martensitic and austenitic stainless steels.
- 316 steel and 316L steel: 316L steel is a type of austenitic stainless steel whose carbon content does not exceed 0.02%, the amount of chromium is around 17% and the nickel content reaches 10 at 12.5%. To this alloy is added 2 to 2.5% Molybdenum. The L in the abbreviation 316L means that it is a “Low carbon” steel. Indeed, as mentioned previously, this steel contains only 0.02% carbon compared to 0.05% for “classic” 316 steel. When welding at very high temperatures, a substance called "chromium carbide precipitation" is created and therefore the steel, although stainless, becomes more subject to corrosion. Having a minimum of carbon in the structure of this alloy prevents the creation of this precipitation and therefore 316L steel is not subject to corrosion. Molybdenum, discovered in 1778 by Carl Wilhelm Scheele, is added to stainless steel to form 316L steel. On the one hand, Molybdenum hardens the alloy but above all makes it much more resistant to corrosion, even in extreme environments (chlorinated, salty, and acidic environments). This is why 316 L steel is also used for exterior uses such as railings and handrails.