DE289066C - - Google Patents

Description

IMPERIAL / k

PATENTA

For many purposes, e.g. B. for drawing dies, drilling, cutting, turning and engraving tools, As well as for everyday objects of all kinds, the diamond is widely used in technology. It is well known that, besides the high price, the use of the diamond has many other uses has other problems, and many attempts have been made to eliminate the same by one different, better and cheaper. Material too

ίο replace.

Some materials have also become known that are almost as hard as diamond are and seemed called to replace this in technology, z. B. silicon carbide, molyb Danish carbide, tungsten carbide and the carbides of other metals.

The carbides mentioned crystallize more or less loosely during their production crystals sticking together and

»O only sit against mechanical influences low resistance.

All attempts that have been made to bring such carbides into mechanically strong and thus usable forms have resulted

»5 to date with no result.

So was z. B. the production of mechanically strong bodies from silicon carbide by molding the powdered carbide, which is one more or less volatile binder has been added, and by subsequent heating suggested. ;

Furthermore, the production of mechanically strong bodies made of silicon, silicon carbide or boron carbide should be used and boric acid or sodium-free feldspar possible for electrical resistance bodies be.

All of these processes work with binders, which are eliminated from the mass by the firing process or, after some other process, in the ferti remain in the body.

It is now known that the addition of any binders to the originally very hard bodies can increase their mechanical strength, but the hardness of the same reduces, since this also makes the less hard and very brittle binders effective.

For example, electrical resistance bodies made of silicon carbide could probably be made using the methods mentioned but the use of these bodies was very limited, since the heating of the same could never go further than evaporation or up to the melting point of the binding agent. • The production of useful tools from silicon carbide was not successful, and for this reason the use of silicon carbide remained for grinding purposes only j limited. .

In the American patent specification 1023299 has already been suggested, small ball

made of tungsten carbide for storage purposes in measuring instruments etc. that tungstic anhydride or oxide in a carbon crucible by means of an electric arc or electric Resistance heating was melted.

With this method, too, no mechanically so strong pieces were obtained that the Use of tungsten carbide for drawing dies, turning tools, etc. has become possible

ίο, since the tungsten carbide melts, loosely attached to each other in m'fthr or less * straight crystals arise.

V The tungsten or molybdenum carbide obtained in this way shows a rough fracture and is

} 5 -of such low mechanical strength that

', the same could not count as a substitute for the diamond. ■

■ According to the present procedure, it is possible to Body - mainly made of tungsten -

ao or molybdenum carbide, but also from the carbides of other metals of great mechanical strength To produce strength of any size, so that the use of these carbides for drawing dies, tools, bearings and utility

»5 objects of all kinds have now become possible is.

It is characterized by the fact that tungstic anhydride or oxide in the carbon crucible in a furnace of suitable construction is brought to melt, the metals be converted into carbides in a known manner.

According to the present process, the metal carbide thus obtained in a known manner is extremely finely powdered, and the pulverized carbide is pressed into carbon molds without any additives by means of hydraulic presses or other suitable tools.

The carbide is then placed in a furnace of suitable construction until it is close to the melting temperature heated, whereby it is only necessary to ensure that the mass does not melt for the second time and not again into individual parts loosely attached crystals disintegrate.

If the "heating is carried out for a long enough time," begins inside the carbide a new crystallization process which gradually permeates the whole mass.

This creates metal carbide bodies of very high mechanical strength and density, which more or less retain the shape that the powdered mass obtained from pressing in the forms of carbon.

Claims (1)

Patent claim: Process for the production of any size pieces of any shape from tungsten or molybdenum carbide or from a mixture of these carbides for tools and utensils of all kinds, characterized in that the carbides obtained in a known manner are finely powdered in a known manner, whereupon they are pressed into Molds are made from carbon moldings and these are heated in an oven of any construction to close to the melting point of the carbides until a new crystallization process occurs. ;