Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
  • B22F3/12—Both compacting and sintering
  • B22F3/14—Both compacting and sintering simultaneously
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
  • B22F3/24—After-treatment of workpieces or articles
  • B22F3/26—Impregnating

Definitions

• the invention relates to a method for producing molded parts from metal particles by compression molding and subsequent sintering.
• the invention also relates to a sealing element which is produced from a sintered part.
• the production of sintered parts in powder metallurgy from metal particles, in general metal powder, has long been known.
• the metal particles used for this purpose are pressed in the cold or warm state and then sintered. Sintering takes place in a reducing atmosphere at temperatures in the amount of 2/3 to 4/5 of the melting point of the metal particles are carried out. In this process, the metal surfaces bake together and the metal particles solidify.
• Such a sintered part is more fine-grained and uniform than other metal particles and has higher strength properties. It is also relatively porous and has little elongation.
• Sintered parts are used in technology in many areas, e.g. as storage materials and as metal filters for cleaning liquid metals.
• the present invention is therefore based on the object of creating a method for producing a sintered part and a sintered part itself which has high sliding properties and high temperature resistance at the same time.
• this object is achieved in that powdered layered silicate is also pressed into the pores of the sintered part.
• the lubricity of the sintered part is increased even more by the lubricating effect of the graphite. Due to its insulating effect, the layered silicate takes on a protective function for graphite against excessive temperatures. The layered silicate practically envelops the graphite in the pores. The higher the desired temperature, the more mica will be used.
• Such a sintered part can thus be used as a high-temperature-resistant sealing element, because the pores are now closed by the layered silicate or the mixture.
• Such a use is completely surprising and runs counter to the previous knowledge and applications of sintered parts, where their porosity has just been set.
• Layered silicates belong to a large mineral group, which also includes mica and all clay minerals. Allen is an infinitely extended, polar out as a component directed layer of SiO4 tetrahedra together, which in turn form hexagonal rings. From this group, mica in particular has proven to be the most suitable. Of course, however, other layered silicates are also possible for the purpose mentioned, if necessary.
• the mixture is pressed into the pores under vacuum, for which purpose the sintered part is placed accordingly in a vacuum container.
• the introduction of the mixture is facilitated and achieved in an optimal manner if the mixture is pressed into the pores via a liquid carrier medium.
• Oil or water can serve as possible carrier media.
• carrier media are also possible if required.
• the mixing ratio between graphite and layered silicate depends on the application, whereby, as mentioned, only layered silicate may be used alone.
• a mixing ratio of 50:50 is possible, as are deviations of 10, 20, 30 or 40% down and up.
• small metal wire pieces or metal chips are pressed as metal particles instead of metal powder and sintered after molding.
• sintered parts which are produced with the metal wire pieces according to the invention have a significantly higher elasticity and better damping behavior.
• This method can also be used to produce parts with very low density and high material strength are put, with which a high amount of the mixture according to the invention can be introduced into the sintered part.
• the length and diameter of the metal wire pieces depends on the application. In general, pieces of metal wire or metal shavings will be used, which have a diameter or a width of 0.1 to 2 mm and a length of approximately 0.5 to 10 mm, with deviations downwards and upwards being possible within the scope of the invention .
• a sintered part produced according to the invention will be used as the sealing element, which can be exposed to a high temperature load.
• the sintered part When using powder, the sintered part is compression-molded in a mold in a customary manner in a hydraulic or eccentric press and then sintered in a customary manner.
• Graphite powder and mica powder are mixed into a solution of a calibration oil or other oily medium.
• the sintered part is then placed in a vacuum container and then the mixture of graphite powder and mica powder is used under vacuum using the Calibration oil is pressed into the pores of the sintered part as a carrier medium.
• the oil is then pressed out again, for example by heating.
• the proportion of the graphite / mica powder mixture can be up to 10 or more% by weight of the sintered part. The lower the density of the sintered part and the larger the pores, the more graphite and mica powder can be introduced. This applies in particular to a sintered part which is pressed and sintered from pieces of metal wire.

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• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Mechanical Engineering (AREA)
• Powder Metallurgy (AREA)

Applications Claiming Priority (2)

Publications (2)

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ID=6350459

Family Applications (1)

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Cited By (2)

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• 1988
  • 1988-03-23 DE DE3809737A patent/DE3809737A1/de not_active Ceased
• 1989
  • 1989-03-16 EP EP89104732A patent/EP0334212A3/fr not_active Withdrawn
  • 1989-03-20 JP JP1069151A patent/JPH01298102A/ja active Pending

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