Classifications

• • G—PHYSICS
  • G04—HOROLOGY
  • G04D—APPARATUS OR TOOLS SPECIALLY DESIGNED FOR MAKING OR MAINTAINING CLOCKS OR WATCHES
  • G04D3/00—Watchmakers' or watch-repairers' machines or tools for working materials
  • G04D3/0074—Watchmakers' or watch-repairers' machines or tools for working materials for treatment of the material, e.g. surface treatment
  • G04D3/0097—Watchmakers' or watch-repairers' machines or tools for working materials for treatment of the material, e.g. surface treatment for components of the means protecting the mechanism against external influences, e.g. cases
• • G—PHYSICS
  • G04—HOROLOGY
  • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
  • G04B37/00—Cases
  • G04B37/22—Materials or processes of manufacturing pocket watch or wrist watch cases
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/26—Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/26—Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
  • Y10T428/263—Coating layer not in excess of 5 mils thick or equivalent
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/26—Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
  • Y10T428/263—Coating layer not in excess of 5 mils thick or equivalent
  • Y10T428/264—Up to 3 mils
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/26—Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
  • Y10T428/263—Coating layer not in excess of 5 mils thick or equivalent
  • Y10T428/264—Up to 3 mils
  • Y10T428/265—1 mil or less

Definitions

• ABSTRACT [30] Foreign Application Priority Data Method of making a watch case element by forming J 13 1971 S it 1 d 446/71 same of molybdenum and hardenmg by carbunzatlon w zer an producing a surface layer of molybdenum carbide, said carburization being carried out during the final [52] Cl 0 3 manufacturing stage.
• a further treatment of the car- Int Cl 5 5 c23c /6 burized element with hydrogen sulphide results in the Field of Search" U 148/203 6 formation of a dark coloured pol1shab1e surface wh1ch has fine brilliance.
• Watch cases resulting from sintering are strictly limited in their forms and moreover, are very fragile.
• a watch case in stainless steel hardened by nitriding requires, in order to obtain a sufficient corrosion resistance, to be further protected by stainless steel hardened through a layer of chrome such processes imply numerous difficulties.
• the present invention proceeds from the idea of machining a watch case from a material capable of being hardened as a last operation. It is understood that this material must be non magnetic, corrosion resistant, particularly in respect of sea water, easily machinable and capable of either hot or cold forming.
• the method according to the invention is characterized by the fact that one fashions the element of watch case of molybdenum and that one hardens it during the finishing stage by a carburizing treatment, thereby producing on the surface thereof a layer of molybdenum carbide.
• the element of the watch case so obtained is characterized by the fact that it comprises molybdenum having a surface covering of molybdenum carbide.
• Molybdenum has shown itself to respond to the requirements mentioned hereinbefore. It is to be noted that the hardening of the watch case element obtained during final stages of manufacture does not comprise a cementation in the usual sense of this term, i.e. comprising a very hard surface zone united to the interior by a transitional zone. Instead a carburization occurs producing molybdenum carbide at the surface.
• the hardening operation by carburization, is effected by burying the otherwise finished items in a cement of the classic type, by welding shut the container in order to assure a complete sealing thereof, and by bringing this cement to and holding it at a temperature from 1 100 to 1300C for a duration of to hours or still longer should one wish to obtain a very deep carburization.
• the cooling must be effected in the oven and very slowly in order to prevent the carbide zone from becoming fragile. Once the element has reached the room temperature, one can reheat it at a temperature of about 1000C during about two hours, letting it then to cool again very slowly. This improves the diffusion of the hardening layer and reduces the fragility of the element.
• the hardness thus obtained is of the order of 1500 to 1700 Vickers measured by micro-hardness at a load of 500 g.
• the depth of carburization is in the order of 10 to 300 microns according to the temperature and the time. There will be no deformation since molybdenum at 1000C has the same resistance as iron at 20C. A simple polishing will give the desired brilliance.
• the hardening by carburization also can be carried out in a vessel made of a ceramic, the cement of which is constituted by 60 percent of active carbon, 30 percent of graphite and 10 percent of charcoal.
• the duration of the operation will be of about 20 hours, at a temperature of about 1300C, for obtaining a hard layer of a thickness of microns.
• the hardness of such layer is of the order of 1500 to 1600 Vickers at a load of 500 g.
• the hardening also can be carried out under a controlled atmosphere containing 98 percent of hydrogenous and 2 percent of methanol.
• a dark coloured surface having a very fine brilliance and capable of being polished without difficulty may be obtained by treating the carburized items in an atmosphere of hydrogen sulphide at a temperature of about 850C during about 20 minutes, thereby forming a compound molbydenum-sulphide on the surface.
• molybdenum has the property of being easily oxydizable above 500C, various colours such as blue and organge may be obtained through modifying the chemical composition of the surrounding atmosphere or by means of a galvanic oxydation in baths hardly acid or alkaline, even caustic, i.e. other than neutral.
• Method according to claim 1 characterized by the fact that the hardening is carried out in a cement at a temperature of 1100' to l300C, for a duration of 10 to 15 hours.
• Method according to claim 1 characterized by the fact that the hardening is carried out in a cement constituted by 60 percent of active carbon, 30 percent of graphite and 10 percent of powder of charcoal.
• Method according to claim 1 characterized by the fact that the hardening is carried out during about 20 hours, at a temperature of about 1300C.
• Method according to claim 1 characterized by the fact that once the hardening is effected, the element is reheated at a temperature of about l000C, for a duration of about two hours, and then cooled very slowly.
• Method according to claim 1 characterized by the fact that the element is coloured either by changing the composition of the surrounding atmosphere, or by a galvanic treatment in a bath other than neutral.
• a watch case element formed of molybdenum and having a surface layer of molybdenum carbide formed by hardening during the final manufacturing stage by carburization.
• a watch case element as claimed in claim in which said molybdenum carbide surface layer has an outer layer formed of a compound of molybdenumsulfide.
• a watch case element as claimed in claim 10 in which said molybdenum carbide surface layer has a hardness in the range of the order of 1500 to 1700 Vickers measured by micro-hardness at a load of 500 grams.
• a watch case element as claimed in claim 10 in which said molybdenum carbide surface layer has a thickness of the order of from 10 to 300 microns.
• a watch case element as claimed in claim 10 in which said molybdenum carbide surface layer has a hardness in the range of the order of 1500 to 1700 Vickers measured by micro-hardness at a load of 500 grams and a thickness of the order of from l0 to 300 microns.
• a watch case element as claimed in claim 10 in which said surface layer has a colour which is the result of changing the chemical composition of the surrounding atmosphere in the course of heat-treating same.
• Method according to claim 3 characterized by the fact that the hardening is carried out for a duration of about 20 hours, at a temperature of about l300C.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
• Carbon And Carbon Compounds (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=4187208

Family Applications (1)

Country Status (7)

Cited By (4)

Citations (3)

Family Cites Families (2)

• 1972
  • 1972-01-04 FR FR7201481A patent/FR2121884B1/fr not_active Expired
  • 1972-01-05 GB GB53472A patent/GB1344582A/en not_active Expired
  • 1972-01-05 IT IT47567/72A patent/IT948106B/it active
  • 1972-01-07 DE DE19722201349 patent/DE2201349A1/de active Pending
  • 1972-01-07 US US00216275A patent/US3772096A/en not_active Expired - Lifetime
  • 1972-01-13 JP JP610872A patent/JPS5431975B1/ja active Pending
• 1976
  • 1976-10-07 HK HK623/76*UA patent/HK62376A/xx unknown

Patent Citations (3)

Also Published As

Similar Documents