DE1293528B - Plumb stick for brazing metallic materials - Google Patents

Description

When brazing materials with different thermal expansion coefficients arise after the solder has solidified in the course of further cooling of the soldered joint high tensions due to the mutual locking of the two soldered workpieces. In order to achieve good soldered connections, the surfaces to be connected must be separated from the liquid Solder are well wetted and those remaining in the soldered joints after cooling Tensions are kept as low as possible.

While now the solder on the one hand for the achievement of low voltages a low solidification temperature and thus the smallest possible temperature range for cooling after solidification is supposed to have, on the other hand for a light Flow of the solder and good wetting of the soldering surfaces in addition to using an appropriate one Flux mainly has a certain degree of fluidity and a correspondingly high temperature the workpieces to be connected may be necessary.

The use of a temperature above the melting point of the solder However, temperature is only possible if leakage from the soldering gap can be avoided and if the temperature can also be measured.

However, these prerequisites are: in practice mostly not applicable and are particularly important in slot soldering, as they are, for. B. with carbide-tipped Tools appear difficult to implement.

For these reasons, a range pole would be desirable, which on the one hand has a high melting point, but on the other hand the deposited solder solidified only at relatively low temperatures.

The present invention is based on the consideration to Creation of such a range pole two different metallic materials in this way to use that the material with a higher melting point the material with relative lower melting point tightly encloses on all sides and the two materials in to choose such proportions that the solder formed from them is eutectic.

A precipitation of primary crystals as a result of inevitable smaller ones In practice, fluctuations in concentration cannot be completely suppressed be, but this is hardly an impairment, since the overwhelming majority the remaining residual melt has the low solidification point of the eutectic. A range pole is already known, its core made of silver and its jacket consists of copper, but it is not known to use the core metal in portions To arrange coat and to enclose tightly on all sides with this and the proportion of to measure the two metals so that the deposited solder is eutectic.

There is also a pole made of a eutectic copper-phosphorus alloy known whose core is as thin as possible in order to improve the drawability Copper tube is enclosed, with the phosphorus content of the core as high is that it covers the missing phosphorus content of the coat.

Apart from the fact that such a copper-phosphorus eutectic is a metallic one and contains a non-metallic component and therefore for the purpose of our invention does not come into consideration, this pole also lacks the feature of portion-wise Subdivision of the core. It is true that plumbing rods have already become known, in their core the flux arranged in portions .. and enclosed on all sides by the jacket is to prevent it from flowing out as a lower melting component, however this measure would make little sense in the case of the above-mentioned plumbing rods, since with these it is not necessary to avoid differences in the concentration of the plumb bob is still being sought and its intended use depends on the intended use of the application according to the application Range is different.

With the range pole according to the invention is both the achievement of the Soldering necessary temperature due to the high melting point of the jacket material without Temperature measuring device secured as well as the requirement realized that when cooling the soldered connection is only blocked when the temperature is as low as possible should, because such a temperature only occurs after the eutectic solidification temperature has been fallen below can occur.

When melting down such solder rods, which are useful in rod or Are produced in strip form, experience has shown that an oxide skin of the jacket material remains stand briefly, which is then dissolved by the flux. This skin makes it difficult now z. B. with slot soldering the running out of the thin mixed solder during the first cooling period.

The invention now relates to a plumbing rod for brazing metallic Materials with different coefficients of thermal expansion, consisting of made of two different metals, the one melting at a lower temperature Metal, optionally together with flux, forms the core, while the higher temperature melting metal envelops the core, and the invention exists in that the core metal is arranged in portions in the jacket and on all sides this is tightly enclosed and that the two metals are present in such proportions are that the plumb bob is eutectic.

For example, such a range pole consists of the one at around 1080 ° C melting copper and from the silver melting at around 960 ° C, that in portions is tightly enclosed on all sides by the copper and that together with the copper Forms eutectic, which solidifies at around 780 ° C.

The manufacture of solder rods according to the invention can be carried out like this is shown in the drawing in principle form. From a hollow cylinder 1 the metallic material used with a higher melting point with the help of profiled rollers 2 contiguous, sealed against each other Formed pockets, a pocket in this one before each closing appropriately cut, z. B. rod or strip-shaped piece 4 with accordingly dimensioned cross-section made of the metallic material with a low melting point is introduced.

With the aid of a cutting device 3, the filling material can continuously corresponding lengths 4 are cut off in those time segments in which the pockets to be formed from the hollow cylinder 1 by the profiled rollers 2 continuously are closed from bottom to top, the so divided into portions Filling material for filling the pockets in a row from top to bottom into the Hollow cylinder is introduced.

The filler material 4 can be used immediately after separation by the cutting device 3 in portions for filling the pockets in the hollow cylinder 1 fall into it.

When using the solder rods according to the invention, the pocket-shaped Divisions separated in the required length at a pinch point. One frequent subdivision into pockets is necessary in order to obtain locally widely different concentrations to avoid the problem of larger solder joints by merging the one that melts first Filler material could occur.

It is of course possible to compare the filler material from the lower melting metallic material with a suitable, known per se To provide flux, for example by dipping in a suitable solution, slurry or in a suitable melt and by subsequent drying.

Finally, if so desired, it is also possible to use those according to the invention Roll out solder rods into strips or foils.

Claims (6)

Claims: 1. Solder stick for brazing metallic materials with different thermal expansion coefficients consisting of two different Metals, the metal melting at low temperature, optionally together with fluxes, it forms the core, while the one which melts at a higher temperature Metal envelops the core, thereby showing that the core metal is arranged in portions in the jacket and is tightly enclosed on all sides by this and that the two metals are present in such proportions that the deposited Lot is eutectic. 2. Range pole according to claim 1, characterized in that the at a lower temperature melting metallic material silver and the at The higher temperature melting metallic material is copper. 3. A method for producing a range pole according to claims 1 and 2, characterized in that from a hollow cylinder (1) from the coming to use metallic material with a higher melting point with the help of profiled rollers (2) cohesive, mutually sealed pockets are formed and that before the respective closure of a bag in this a correspondingly cut to length, z. B. rod-shaped or strip-shaped piece (4) made of the metallic material with a lower melting point is introduced. 4. The method according to claim 3, characterized in that a cutting device (3) from the z. B. in rod or strip form filler material continuously cuts corresponding lengths (4) in those time segments in which the pockets to be formed from the hollow cylinder (1) by the profiled rollers (2) are continuously closed from bottom to top and that in such a way Filling material divided into portions for filling the pockets is introduced into the hollow cylinder (1) one after the other from top to bottom. 5. Method of manufacture a range pole according to one of the preceding claims, characterized in that that the filler material is provided with a flux, for example by dipping the comparatively lower melting point metallic material into a suitable one Solution, slurry or in a suitable melt and then drying. 6. A method for producing a range pole according to one of the preceding claims, characterized in that from the hollow cylinder (1) with the help of the profiled rollers (2) coherent, mutually separated pockets are formed and each filled with filler material (4) before they are closed and that the plumb rod obtained in this way is then rolled out into strips or foils.