DE897793C - Process for the production of hard metal supports on metal bodies - Google Patents

Description

Process for the production of hard metal supports on metal bodies For producing surfaces of particular hardness on tools or other metal objects it is known that the objects made of softer metal with a support plate made of very hard metal.

The invention relates to the production of hard metal supports on the surface of metallic bodies and is aimed at agglomerates in the form of bars in the form of solder bars or as plates or disks, those under heating, e.g. B. by means of a soldering tube or electric arc, are meltable and are thus melted onto tools or other metal bodies can.

To carry out the method according to the invention, a metal or metalloid carbides, silicides and / or other hard metals with cobalt as Used agglomerate made of binding agent, to which further additives are added that either volatilize or through when the agglomerate melts chemical reaction in the heat taken up by one of the constituents of the agglomerate can be. Such additives can either be made from one with sufficient heating vaporizing metal, such as zinc, magnesium, lead, cadmium or the like., exist or from alloys with a low melting and volatilization point or from sufficient solid organic materials, especially synthetic resins, which are very little used when glowing Tend to form ashes, or from salts with low melting and evaporation temperatures, like silicates or borates, or finally from acids like boric acid, which are in the Heat to be excreted. The method of the invention is described in more detail using the following exemplary embodiments: Example i Made of finely powdered Metal or metalloid carbides, such as. B. tungsten, titanium, tantalum, vanadium, boron or other carbides, a homogeneous mixture is first produced. This mixture is mixed with cobalt as a binding agent and is also given a very small one Addition of a second organic binder, preferably synthetic resin or others organic substances that harden when exposed to heat and are subject to polymerization. The mixture is dried, shaped into rods or plates and then fired, whereby the organic component disappears except for very small traces, during the Cobalt used as a binder gives the agglomerate a certain strength.

In order to produce the hard metal coating, the one to be provided with it is heated Metal body to a very high temperature and then touches it with the agglomerate rod, which softens quickly due to its low melting point and is at the desired level Melting point of the metal body. The heating is now continued vigorously until to glow in order to cause the binder to precipitate by volatilization. The applied metal solidifies and can even in this state be forged. After cooling, the workpiece is finished. One can In this way, layers of hard metal can be applied to precisely defined areas. Examples A homogeneous mixture is first prepared as for example i finely powdered metal or metalloid carbides. Besides cobalt one uses as further binders metals, e.g. B. Magnesium, zinc, lead, cadmium etc., or salts, such as silicates or borates, or acids that evaporate easily when exposed to heat, e.g. B. boric acid, which secures the binding of the components. The mixture thus prepared becomes when appropriate Temperature and sufficiently high pressure brought into the desired shape while hot.

To apply the hard metal, one touches the one to be provided with it Workpiece with the rod heated to a temperature close to its melting point. With further heating, this melts on the workpiece and adds to it the hard metal lining.

The rods or the like produced from the agglomerate can be different Have profiles: The application of the supports on the workpieces can be carried out by electrical build-up welding. Here the rod is attached to one pole, the workpiece to be occupied is connected to the other pole of an electrical line. You rub and then rotate the rod on the workpiece, being at the point of contact a spark or arc is created that heats the contact points and the rod melts. The hard metal agglomerate flows onto the surface to be covered Workpiece and connects to it. In order to achieve a loss of hard metal through To prevent spray-off, glowing particles, the workpiece and the rod expediently wetted at the point of contact by a jet of liquid.

The application of the hard metal to the workpiece by means of electrical Electricity can of course also be generated by a process similar to spot welding, wherein the electrode can consist of a rod made from the agglomerate.

Claims (4)

PATENT CLAIMS: i. Method for applying a hard metal coating on metal surfaces, characterized in that one of metal or metalloid carbides, silicides and / or other hard metals, a metallic binder, preferably Cobalt, and other additives produced agglomerate with heating, e.g. B. by means of a soldering tube or electric arc on the object to be covered is applied. 2. The method according to claim i, characterized in; that this Agglomerate made from a homogeneous mixture of finely powdered metal and metalloid carbides with cobalt as a binder and an addition of synthetic resin or other organic, manufactured with heat-hardening substances that do not melt under high pressure, Shaped into rods or plates and fired, then on the object to be covered first brought to melt with heating and then for the purpose of precipitating the organic constituents are heated further until they glow and solidify. 3. Method according to claim? ", Characterized in that instead of the addition of Synthetic resin or other organic substances an addition of metals such as magnesium, Zinc, lead, cadmium or the like. Or from! Salts, such as silicates or borates, or acids that evaporate easily when exposed to heat, e.g. B. boric acid, or of alloys, all with a low melt bait liquefaction point is used. 4. Procedure according to claim i, characterized in that the application of the hard metal coating by way of electric arc deposition welding with constant turning of the to be applied agglomerate and keeping the contact point moist.