Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C1/00—Making non-ferrous alloys
  • C22C1/04—Making non-ferrous alloys by powder metallurgy
  • C22C1/05—Mixtures of metal powder with non-metallic powder
  • C22C1/051—Making hard metals based on borides, carbides, nitrides, oxides or silicides; Preparation of the powder mixture used as the starting material therefor
  • C22C1/053—Making hard metals based on borides, carbides, nitrides, oxides or silicides; Preparation of the powder mixture used as the starting material therefor with in situ formation of hard compounds

Definitions

• This invention relates to improvements in the manufacture of tools and other objects subjected to abrasion, from sintered hard metal carbides or like material.
• additional metals are partly to facilitate the sintering of the pulverous hard material to a dense body of a considerable hardness, partly to increase the toughness of the material.
• other metals as for instance W, Mo, Ti or V may be added.
• a solidifying binder such as dextrine or shellac
• the tool has been given the shape desired by means of mechanical treatment after solidification of the binder.
• this method has proved not to be suitable in practice, partly as it is very hard to obtain a homogeneous distribution of the binder in the form piece, partly as the product is easily made impure by the percentage of ash of the binder.
• the said form pieces are subjected to a heating up to a temperature of 700-ll C., at which temperature the added auxiliary metal (Fe, Co, or Ni) acquires a binding effect.
• the form pieces may be worked by ordinary tools,
• the present invention relates to a process of making tools and the like from a pulverous mixture, which consists of a hard metal carbide, boride, silicide, or nitride, and one or more softer added auxiliary metals, ,such as iron, cobalt, or nickel, possibly together with one or more hard metals, such as tungsten, molybdenum, titanium, or vanadium, the final shape by mechanical working being given after the said mixture has been pressed to a form piece, after which working the final sintering is efiected.
• a pulverous mixture which consists of a hard metal carbide, boride, silicide, or nitride, and one or more softer added auxiliary metals, , such as iron, cobalt, or nickel, possibly together with one or more hard metals, such as tungsten, molybdenum, titanium, or vanadium, the final shape by mechanical working being given after the said mixture has been pressed to a form piece, after
• the mixture is subjected, before, after, or during the pressing, to the influence of such substances as with a chlorinating action attack the surfaces of the powder of the auxiliary metal, for example by addition of or treatment by chlorides, so that a coherent form piece is obtained, which is worked and then, possibly after the portion of the chlorinating substances which is still present has been expelled and the compounds formed have been decomposed for instance by reduction, and possibly after a subsequent pressing, is subjected to the final sintering.
• the converting of the metal surfaces into chlorides may for instance be effected by mixing the pulverous mixture with dry powdered ammonium chloride; the powdered ammonium chloride may also be mixed during the grinding together of the hard particles with the softer auxiliary metal. of course, the pulverous mixture may also be moistened by means of a solution of ammonium chloride either in water or in suitable organic solvents, such as methyl alcohol or the like.
• the form pieces become sufficiently well bound together to enable them to be worked to the desired shape.
• it has proved to be suitableto employ heat treatment after the pressing but before the mechanical working to desired shapes, possibly in combination with the expelling of parts of the chlorinating substances which are still present or decomposition of the compounds formed, for instance by reduction.
• the said treatment may be carried out with the effect desired at a very low temperature, in any case below 600 0., preferably at 400-500 C.
• the product obtained may in this way be given an extraordinary suitable consistency for the working intended, and the wear and tear of the tool used becomes extremely small.
• the method may be varied in dlfierent ways: The procedures mentioned must be regarded only as examples. It should be noticed that it is suitable to remove from the product the reaction products obtained in the form of gas and without it being necessary to raise the temperature too high, since a removal of heavy salts at high temperatures will easily cause the formation of blow holes in the material.
• the first pressing is carried out at a relatively low pressure, for example 1000 kgs/cm
• the second pressing operation after the heat treatment taking place at a considerably higher pressure for example 10,000 kgs/cm.
• step of chlorinating may take place prior to, during. or subsequent to, the step of pressing.
• the process of making solid bodies from a pulverous mixture which comprises mixing a comminuted compound of a hard metal, such as tungsten, tantalum, or titanium, and a metalloid, such as carbon, boron, or nitrogen, and at least one softer additional metal, such as iron, cobalt, or nickel, chlorinating the softer additional metal with ammonium chloride, and pressing the mixture into form pieces which are worked to the desired shape.
• a hard metal such as tungsten, tantalum, or titanium
• a metalloid such as carbon, boron, or nitrogen
• at least one softer additional metal such as iron, cobalt, or nickel
• the pulverous mixture contains, in addition, a hard metal, such as tungsten, tantalum, or titanium in metallic form.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Powder Metallurgy (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=20424263

Family Applications (1)

Country Status (4)

Cited By (11)

Families Citing this family (1)

• 0
  • FR FR745076D patent/FR745076A/fr not_active Expired
  • NL NL34502D patent/NL34502C/xx active
• 1932
  • 1932-11-01 GB GB30781/32A patent/GB408716A/en not_active Expired
  • 1932-11-03 US US641117A patent/US1996220A/en not_active Expired - Lifetime

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