SU59113A1 - Pa lnik - Google Patents

Description

The process of paing metal products, as is well known, consists in the fact that a low-melting solder enters into chemical interaction with the surface layers of the metals being welded, as a result of which a very strong adherence to the metal is obtained.

In the case of aluminum fusion, the surface film of aluminum oxide interferes with soldering to metal, with which none of the known metal alloys interacts.

A series of chemical and mechanical methods have been proposed to remove this film. Chemical methods are based on the fact that the alumina film dissolves when heated in some fluorine-containing compounds. Other methods are based on the mechanical removal of an alumina film by rubbing with an abrasive powder on the surface of an aluminum product coated with molten solder. In practice, mainly the latter methods are used. However, due to the fact that the proportion of solders is greater than the proportion of abrasive, the powder of the latter floats on the surface of the solder; As a result, the process of stripping the film with powdered abrasive is carried out with considerable difficulty and requires great experience of the worker.

Abrasive powder can be replaced with an abrasive rod. This facilitates the work, but it has the disadvantage that, along with the PA, the abrasive rod must also be heated. Inserting a piece of an abrasive rod into a blade does not reach the goal, since, due to the poor thermal conductivity of the abrasive product, its temperature during normal heating of the blade is insufficient to melt the aluminum solder.

The heat capacity and thermal conductivity of an abrasive rod can be significantly improved if an abrasive powder (carborundum, corundum, etc.) is introduced into the mass of copper. To this end, according to the invention, small rods are made from a mixture of abrasive powder and copper sawdust using a metal-ceramic method, which are then inserted into the body of the saw blade.

In FIG. 1, 2 and 3 show a cross-sectional view, a plan view and a general view of an ordinary pair with such a metal-ceramic insert; FIG. 4, 5 and 6 are the same for the electric flax.

Here, the numeral I denotes the copper body of the blade, the numeral 2 - a metal-ceramic insert made of copper with an abrasive filler.

Such an abrasive insert is heated to the same extent as the body of the blade. Under the action of heat, the solder melts, and when the insert is rubbing against the surface of the aluminum product, the alumina film is stripped, the metal is exposed, and a low-melting alloy interacts with aluminum.

The solder during the destruction of the aluminum oxide film is not cooled.

In most cases, the alloy used as a solder is not solder, but only serves for half the surface of the aluminum. The usual solder-and-tin solder easily adheres to such a tinned surface, during the work with which it is used as usual.

Prev invented.

Passenger, characterized in that, in order to use it when brazing aluminum to destroy the oxide film under a layer of molten solder and, moreover, without cooling the solder, it is provided with a metal-ceramic insert 2 of copper with an abrasive filler.

fig 1