When did Rolex Change to 904L Steel? Complete Guide
The most common type of stainless steel that most watch companies use is 316L stainless steel.
316L stainless steel is an alloy of iron that is known as high-grade steel or marine grade stainless steel. 316L steel consists of iron, chromium (between 16–18%), nickel (10–12%), and molybdenum(2–3%) and has small (<1%) quantities of silicon, phosphorus & sulfur. By adding molybdenum, the steel gets greater corrosion resistance. There is also 316-grade steel but the “L” in 316L denotes that it is the low carbon version.
Whilst 316L steel is the most commonly used steel in the watch industry, Rolex does not use this steel anymore. So when did Rolex change to 904L steel and why?
In Rolex’s early history, the company used – like most others – 316L stainless steel. This steel is very qualitative steel that has great anti-tarnishing and anti-corrosion properties. It was praised for its resistance to saltwater and acidic liquids thanks to its low carbon content. But whilst it has anti-corrosive properties, it is not corrosion-proof.
Over time, Rolex noticed that some of its watches made in 316L stainless steel would develop tarnish and pitting in some places. This primarily happened on the case behind the bracelet and underneath the case behind the case back. This is particularly true for watches worn in humid climates and frequently to corrosive liquids like saltwater.
Since rusting and pitting is not something you want in a watch, Rolex started thinking about how it could prevent this in the future. Their answer was a different type of alloy, namely 904L stainless steel.
When did Rolex change to 904L stainless steel?
The information about when Rolex completely exchanged 904L for 316L steel varies. But Rolex themselves states that “Rolex’s steel watches are manufactured from Rolex’s own 904L alloy, known as “Oystersteel” from 2018.”. So according to Rolex, they shifted all of its steel watches to 904L in 2018. But this is not the whole truth. In 2018 at Baselworld, Rolex started to use the term “Oystersteel” to refer to the 904L steel. The steel didn’t change, but the terminology did. From then, Rolex stopped using the term “904L”.
The shift to 904L for all of its watches happened long before this. In 2003, Rolex shifted all of its steel watches to 904L.
The process of moving to 904L steel was not immediate and Rolex started to introduce the new stainless steel for some of its watches at a time.
According to Rolex, they became the first watch manufacturer to use 904L grade steel in their watches in 1985. This statement has, however, been challenged by a number of sources claiming that Omega was actually the first to use 904L in the Ploprof diver, approximately in 1972. Rolex themselves has stated, “In 1985, Rolex became the first watchmaking brand to use this steel from the 904L family for its cases.”. But if Omega was in fact the first, then it is obviously a lot of smoke and mirrors from Rolex, as with many watch companies in their marketing and communication.
After doing some research, we can say that Omega experimented with 904L for the PloProf dive watches in around 1971-1972. Omega got the idea from the French diving company COMEX, which used 904L steel in its diving bells because of its superior corrosion resistance in salt water.
To create the impression of the steel being proprietary (like so many other elements of Rolex watches), Rolex named it Oystersteel. But whilst the use of 904L was an important step, Rolex did not invent 904L steel as Rolex wants us to believe. In Rolex’s marketing when the company talks about the 904L steel, they formulate the sentences in a way that the public should believe that Rolex invented the alloy.
“…a steel alloy specific to the brand. Oystersteel belongs to the 904L steel family, which is particularly resistant to corrosion and acquires an exceptional sheen when polished.”
“Rolex’s steel watches are manufactured from Rolex’s own 904L alloy, known as “Oystersteel” from 2018.”
Naturally, Rolex has its own composition alloy, likely within the percentages above, but it’s still 904L steel. At the same time, we can be certain that Rolex has done a lot of experimenting and testing to find the perfect composition with the best properties.
The first Rolex watch to use 904L stainless steel was the Sea-Dweller in 1985. This makes sense because the primary reason that Rolex switched to 904L was its improved anti-corrosive properties. In other words, to prevent rust and corrosion. And steel that is subject to corrosive liquids like saltwater tends to corrode faster than those that are not subject to it. And considering the fact that the Sea-Dweller is a professional diver, you can expect that they will be subject to a lot of it, and on a regular basis.
Rolex chose 904L stainless steel for its greater corrosion resistance but also because it takes a higher polish than other grades of steel. 904L steel is commonly used in high-tech industries like aerospace and chemical industries. Rolex compares the steel with precious metals for their anti-corrosion properties and the fact that they get an “exceptional sheen once polished.”.
What we can say is that Rolex handles the entire manufacturing process for its steel watch components in-house. Whilst they don’t make the steel themselves, they craft every single part in-house. According to Rolex, they had to invest heavily in developing new machines that would allow them to craft the 904L steel instead of the 316L steel as the latter does not machine as well.
In the company’s own words
“…a steel so incredibly difficult to machine, that special equipment had to be built. Only one watchmaker would consider using it: Rolex.”
The bottom line is that 904L solved the issue that some older Rolex watches developed, namely pitting and corrosion on the case. This is thanks to the fact that 904L steel has molybdenum that gives it superior resistance to localized attacks of pitting and crevice corrosion. Furthermore, its copper addition also gives it corrosion resistance to all concentrations of sulphuric acid.
The composition of 904L stainless steel is as follows:
- Nickel, 23–28%
- Chromium, 19–23%
- Carbon, 0.02% maximum
- Copper, 1–2%
- Molybdenum, 4–5%
- Manganese, 2% maximum
- Silicon, 1.0% maximum
- Iron, (balance)
Since Rolex is a company that is very secretive about its production process, Rolex has never publicly said the exact recipe for the 904L steel that it uses.