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Anti-magnetic (non-magnetic) watches are those that are able to run with minimal deviation when exposed to a certain level of magnetic field. The International Organization for Standardization issued a standard for magnetic-resistant watches, which many countries have adopted.
The international standard ISO 764 Horology—Magnetic resistant watches defines the resistance of watches to magnetic fields. According to ISO 764 or its equivalent DIN 8309 (Deutsches Institut für Normung - German Institute for Standardization) a watch must resist exposure to a direct current magnetic field of 4800 A/m. The watch must keep its accuracy to ±30 seconds/day as measured before the test in order to be acknowledged as a magnetic-resistant watch. Annex A of ISO 764 deals with watches designated as magnetic resistant with an additional indication of intensity of a magnetic field exceeding 4800 A/m.[ citation needed ]
There are two ways of building an anti-magnetic watch:
The first recorded experiments in anti-magnetic watch-making are in 1846. Watchmakers from Vacheron Constantin were among the first to experiment with anti-magnetic features of a watch. However, they succeeded in assembling the first antimagnetic watch only several decades later. That watch was able to withstand magnetic fields because some of its parts were made of non-magnetic metals: the palladium-made balance wheel, balance spring and the lever shaft.
In 1896 Charles Édouard Guillaume discovered the nickel based alloy Invar. Afterwards, in 1920, when he received the Nobel Prize in Physics, he developed another alloy - Elinvar. These alloys assisted in the assembly of anti-magnetic watches. Invar and Elinvar are able to resist magnetic fields, allowing the watch to continue to keep accurate time.
The first anti-magnetic pocket watch was assembled by Vacheron Constantin in 1915.
In 1930, Tissot produced the first ever non-magnetic wristwatch. [2]
Since their appearance, anti-magnetic watches have been favored by people who deal with high magnetic fields. They are widespread among electronic engineers and in other professions where strong magnetic fields are present.
Today, even divers' watches (according to ISO 6425) must be anti-magnetic as well as being water resistant, sufficiently luminous, shock resistant and have solid straps.
After discovering the alloys for assembling anti-magnetic watches, many watch-making brands utilize such materials in production in order to improve the performance of such timepieces.
In 1989 IWC first manufactured the Ingenieur Reference 3508, [3] which was able to withstand huge magnetic fields of up to 500000 A/m.
The Omega Anti-Magnetic Seamaster was announced 17 January 2013 (e.g. Seamaster Aqua Terra > 15,000 Gauss). According to the press release, the OMEGA movement does not rely on a protective container inside the watchcase but on the use of selected non-ferrous materials in the movement itself. The OMEGA prototype was subjected to 1.5 Tesla (15,000 Gauss) and continued to perform. Testing showed that the watch was as accurate after its magnetic exposure as it had been before.
The Rolex Milgauss series of antimagnetic certified chronometers was first manufactured in 1954 with the model 6541 for those working in nuclear, aircraft, and medical settings associated with strong magnetic fields. The watch has an advertised magnetic flux density resistance of 1,000 Gauss within magnetic fields of 80,000 A/m. In 2007, after being out of production for nearly two decades a new Milgauss was introduced as the model number 116400.
Certain diving watches produced by Sinn as mission timers (in German: "Einsatzzeitmesser") for professional users are also protected against magnetic fields up to 1,000 Gauss / 80,000 A/m, using a protective sheath consisting of a closed, magnetically soft inner case that includes the dial, the movement holding ring and the case back. [1]
The Swiss Federal Institute of Metrology (METAS) has METAS N001 requirements for movements and mechanical watches resistant to magnetic fields of 1.5 Tesla (15,000 Gauss). The METAS N001 certification demands a series of tests were amongst other relevant requirements the watches are subjected to strong magnetic field exposures without resulting in the movement stopping or a 0 to ≤5 seconds daily rate deviation. [4]
Beryllium copper (BeCu), also known as copper beryllium (CuBe), beryllium bronze, and spring copper, is a copper alloy with 0.5–3% beryllium. Copper beryllium alloys are often used because of their high strength and good conductivity of both heat and electricity. It is used for its ductility, weldability in metalworking, and machining properties. It has many specialized applications in tools for hazardous environments, musical instruments, precision measurement devices, bullets, and some uses in the field of aerospace. Beryllium copper and other beryllium alloys are harmful carcinogens that present a toxic inhalation hazard during manufacturing.
Invar, also known generically as FeNi36, is a nickel–iron alloy notable for its uniquely low coefficient of thermal expansion. The name Invar comes from the word invariable, referring to its relative lack of expansion or contraction with temperature changes, and is a registered trademark of ArcelorMittal.
Charles Édouard Guillaume was a Swiss physicist who received the Nobel Prize in Physics in 1920 in recognition of the service he had rendered to precision measurements in physics by his discovery of anomalies in nickel steel alloys. In 1919, he gave the fifth Guthrie Lecture at the Institute of Physics in London with the title "The Anomaly of the Nickel-Steels".
Omega SA is a Swiss luxury watchmaker based in Biel/Bienne, Switzerland. Founded by Louis Brandt in La Chaux-de-Fonds in 1903, the company formerly operated as La Generale Watch Co. until incorporating the name Omega in 1903, becoming Louis Brandt et Frère-Omega Watch & Co. In 1984, the company officially changed its name to Omega SA and opened its museum in Biel/Bienne to the public. Omega is a subsidiary of The Swatch Group.
The Contrôle officiel suisse des Chronomètres (COSC), the Official Swiss Chronometer Testing Institute, is the institute responsible for certifying the accuracy and precision of Swiss watches.
Vacheron Constantin SA is a Swiss luxury watch and clock manufacturer founded in 1755. Since 1996, it has been a subsidiary of the Swiss Richemont Group. Vacheron Constantin is the second oldest Swiss manufacturer and one of the oldest watch manufacturers in the world with an uninterrupted watchmaking history since its foundation in 1755. It employs around 1,200 people worldwide as of 2018, most of whom are based in the company's manufacturing plants in the Canton of Geneva and Vallée de Joux in Switzerland.
Swatch is a Swiss watchmaker founded in 1983 by Ernst Thomke, Elmar Mock, and Jacques Müller. It is a subsidiary of The Swatch Group. The Swatch product line was developed as a response to the "quartz crisis" of the 1970s and 1980s, in which inexpensive, battery-powered, quartz-regulated watches were competing against more established European watchmakers, focused on artisanal craftsmanship producing mostly mechanical watches.
ETA SA Manufacture Horlogère Suisse designs and manufactures quartz watches and both hand-wound and automatic-winding mechanical ébauches and movements. Commonly referred to as ETA, the company is headquartered in Grenchen, Switzerland, and is a wholly owned subsidiary of The Swatch Group.
A balance wheel, or balance, is the timekeeping device used in mechanical watches and small clocks, analogous to the pendulum in a pendulum clock. It is a weighted wheel that rotates back and forth, being returned toward its center position by a spiral torsion spring, known as the balance spring or hairspring. It is driven by the escapement, which transforms the rotating motion of the watch gear train into impulses delivered to the balance wheel. Each swing of the wheel allows the gear train to advance a set amount, moving the hands forward. The balance wheel and hairspring together form a harmonic oscillator, which due to resonance oscillates preferentially at a certain rate, its resonant frequency or "beat", and resists oscillating at other rates. The combination of the mass of the balance wheel and the elasticity of the spring keep the time between each oscillation or "tick" very constant, accounting for its nearly universal use as the timekeeper in mechanical watches to the present. From its invention in the 14th century until tuning fork and quartz movements became available in the 1960s, virtually every portable timekeeping device used some form of balance wheel.
Elinvar is a nickel–iron–chromium alloy notable for having a modulus of elasticity which does not change much with temperature changes.
Nivarox, also known as Nivarox - FAR SA is a Swiss company formed by a merger in 1984 between Nivarox SA and Fabriques d'Assortiments Réunis (FAR). It is currently owned by the Swatch Group. Nivarox is also the trade name of the metallic alloy from which its products are fabricated. Its notable property is that its coefficient of elasticity is remarkably constant with temperature. Nivarox is most famous for producing hairsprings that are attached to the balance wheel inside a mechanical watch movement, as well as mainsprings which provide the motive power for the watch.
Glucydur is the trade name of a metal alloy with a low coefficient of thermal expansion, used for making balance wheels and other parts of mechanical watches.
A helium release valve, helium escape valve or gas escape valve is a feature found on some diving watches intended for saturation diving using helium based breathing gas.
A diving watch, also commonly referred to as a diver's or dive watch, is a watch designed for underwater diving that features, as a minimum, a water resistance greater than 1.1 MPa (11 atm), the equivalent of 100 m (330 ft). The typical diver's watch will have a water resistance of around 200 to 300 m, though modern technology allows the creation of diving watches that can go much deeper. A true contemporary diver's watch is in accordance with the ISO 6425 standard, which defines test standards and features for watches suitable for diving with underwater breathing apparatus in depths of 100 m (330 ft) or more. Watches conforming to ISO 6425 are marked with the word DIVER'S to distinguish ISO 6425 conformant diving watches from watches that might not be suitable for actual scuba diving.
The Rolex Oyster Perpetual Milgauss is a wristwatch model introduced by Rolex in 1956 with model number 6541. The Milgauss was advertised as “designed to meet the demands of the scientific community working around electromagnetic fields”. The first of its kind, it is capable of withstanding magnetic fields of up to 1,000 gauss and became known for being worn by scientists at the European Organization for Nuclear Research (CERN) in Geneva. Its resistance to magnetic interference stems from a shield inside the case made of ferromagnetic alloys, which protects the movement. This shield consists of two components, one screwed to the movement and the other to the case. In addition, its Caliber 3131 movement includes paramagnetic materials.
The Omega Seamaster 200 Omegamatic is a midsize automatic quartz watch that Omega produced from 1997 until 2000. It has stainless steel case and bracelet, screw-in crown and caseback, engraved with the Omega Hippocamp logo, 200 meters water resistant, unidirectional bezel, silver or black dial with orange accents, sapphire crystal (anti-reflective) with magnifying (cyclops) date window, case diameter 36mm, 2.4V capacitor, rotor charging micro generator, quartz controlled stepper motor and quickset date function.
The Omega Seamaster is a line of automatic winding mechanical diving watches from Omega with a history that can be traced back to the original water-resistant dress watch released in 1948. The Seamaster collection is perhaps best known today for the Seamaster Diver Professional 300m model that has been worn in the James Bond movie franchise since 1995. Originally conceived as a dressy, water-resistant timepiece, the Omega Seamaster has evolved to a robust sports watch line typically with a stainless steel case, robust water resistance, and an official certified chronometer certified movement within. The Diver Professional 300m is most famous for its "train track" five link steel bracelet, its helium release valve at the 10:00 position, the wave pattern dial on certain model generations, and the skeletonized handset.
904L is an austenitic stainless steel. It is not harder than 316L, but its molybdenum addition gives it superior resistance to localized attack by chlorides and greater resistance reducing acids and in particular its copper addition gives it useful corrosion resistance to all concentrations of sulphuric acid. There is no difference between 316L and 904L steel in strength and hardness. Both of them have similar Rockwell hardness (HRB) which is less than 95 and their tensile strength are both about 490MPa. Its high alloying content also gives it greater resistance to chloride stress corrosion cracking, but it is still susceptible. Its low carbon content makes it resistant to sensitization by welding and which prevents intergranular corrosion.
Havar, or UNS R30004, is an alloy of cobalt, possessing a very high mechanical strength. It can be heat-treated. It is highly resistant to corrosion and is non-magnetic. It is biocompatible. It has high fatigue resistance. It is a precipitation hardening superalloy.
