Czapek’s secret stainless steel

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Czapek’s secret stainless steel - Czapek & Cie
From the oil rig to the wrist.

To understand how special the stainless steel used in Czapek watches is, you first need a primer in the different types of stainless steel used in watches in general. First of all, let’s consider just what stainless steel is exactly. The term refers to a group of iron alloys that contain 10.5% chrome or more and 1.2% carbon or less. These alloys have a self-replenishing surface layer that gives a high level of protection against corrosion. They are divided into three main subgroups: ferritic, martensitic and austenitic. Since the two former types are both magnetic, it is the austenitic grades of stainless steel that are primarily used for wristwatch cases.

Stainless steel grades can be described by the more specific EN standards or the more general SAE/AISI grades, which are the ones commonly used in watchmaking. One of the most versatile forms of stainless steel, which is also used in lower-priced watches, is SAE grade 304 (EN 1.4301), which comprises 18% chromium and 8% nickel. The most common grade used in luxury watches, however, is 316 or 316L, which in addition contains up to 2.5% molybdenum, giving it greater resistance to corrosion. As a notable exception, Rolex uses 904L stainless steel for its cases. This particular alloy also contains copper and has been favoured by Rolex since the 1980s because it takes a higher polish, even though it is more difficult to machine.

Czapek’s secret stainless steel



Czapek & Cie., however, insist that the stainless steel they use for their watch cases does not belong to the austenitic family at all. The company worked with Swiss steel producer Montanstahl in Stabio, Switzerland to use a type of steel never before used in watchmaking. Czapek has baptized its special style with the mysterious “XO” name. A bit of research reveals that there is type of steel called duplex stainless steel that is used in construction and offers greater strength and higher corrosion resistance. Duplex steel has been used in the construction of pedestrian bridges and as handrails in high-corrosive environments such as the Canary Islands, but also in the extreme acidic and seawater conditions that Czapek claims its XO steel is normally used in. But there are also super duplex and hyper duplex steels, as well as lean duplex steels for less demanding environments, which would surely include watchmaking. During the SIHH week earlier this year, Czapek’s CEO Xavier de Roquemaurel, confirmed that the stainless steel used by the company is indeed a duplex steel and that they may soon reveal which one exactly. Hopefully the mystery will soon be solved…

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