Stainless watches gain market share

Despite the popularity of electronic watches and the prediction that they would completely replace traditional mechanical watches, the latter have survived and are making a strong comeback, especially in the high-quality, luxury market.

Until about 10 or 15 years ago, the cases and bracelets of the most expensive, luxurious wristwatches were made of precious metals, mostly gold in all of its many different colours. Nickel-containing stainless steels were preferred only by adventurous types such as pilots, divers, astronauts, explorers, scientists and military officers. But recent years have seen a shift toward nickel stainless steel for even the most exclusive watches.

A generation ago, one bought a gold watch and kept it for life. Today, it is not uncommon for one to have several watches made of nickel stainless steel — a different one for each social occasion. A similar trend is true for jewelry. This is not surprising given that today’s high-priced watches often resemble jewelry. Time-keeping is now just one of many functions performed by wristwatches; resisting water pressure and corrosion is another.

The market breakthrough came with the ability to mount precious stones on stainless steel. Compared with precious metals, stainless is extremely hard, making it difficult to work; it was therefore a challenge to cut it with precision, make the necessary holes, and integrate the prongs that are required to hold the stones.

The first nickel stainless steel wristwatches appeared in 1930, since which time their use has steadily increased. In 1999, the value of nickel stainless steel watches produced in Switzerland reached 40% of the value of all watches made with precious metals.

The nickel stainless alloys used for watch cases and bracelets are highly resistant to corrosion, in particular to seawater and sweat. Typical examples of the high-quality nickel stainless steel alloys used for watches and bracelets are EN 1.4404 and EN 1.4435 (both S31603) and EN 1.4539 (UNS N08904). Although they contain nickel, these alloys will not pose a problem for people with nickel allergy. That’s because nickel allergy occurs when the corrosion products of certain insufficiently corrosion-resistant alloys come into direct and prolonged contact with the skin. If an alloy is of sufficient quality that no corrosion products are produced, there will be no allergy.

Watch manufacturers, particularly in Switzerland, demand strict adherence to chemical compositions and various special properties, all of which are found in nickel stainless steels. These include specific surface finishes, low residual magnetism, a pleasing colour and high mechanical strength for resisting deformation under water pressures at depths of 500 metres or more. High-purity alloys are important as well because different surface finishes on watch cases and bracelets are often situated close to each other. For example, a mirror polish can be combined with a brushed, satin or microshot blasted finish. Nickel stainless steel watch cases and other parts are also produced by metal powder injection-molding, allowing, through the selection of pure powders, made-to-measure chemical compositions.

For nearly 70 years, nickel stainless steels have allowed the Swiss watch-making industry to take advantage of the material’s outstanding properties. At the same time, the industry has gained extensive knowledge in transforming these alloys into cases, bracelets and other parts of outstanding beauty and quality. In this sense, they are truly “noble” alloys.

— The preceding is an excerpt from Nickel, a publication of the Toronto-based Nickel Development Institute.