SU941039A1 - Soldering method - Google Patents

Description

(54) METHOD OF PIKA

The invention relates to the field of soldering, namely, to induction capillary soldering of a telescopic connection with simultaneous action on the connected elements by mechanical vibrations, primarily ultrasonic frequency, and can be used in the manufacture of electronic vacuum tube assemblies.

A known method of soldering a telescopic joint, including assembling the male and female elements, induction heating to the solder melting temperature with the effect of ultrasonic vibrations on one of them, exposure and cooling 1.

The application of this method for induction brazing of telescopically connected elements of complex and irregular shape, such as EVP nodes, especially with their longitudinal dimensions, smaller / 2 waves of excited oscillations, becomes difficult because of the difficulty of achieving intensive excitation of oscillations in the soldering zone.

The irregular oscillations arising under the method of excitation under consideration are not chaotic. At the same time, the effect of ultrasonic vibrations on the solder does not allow one to fully realize the possibilities of their influence on the melt,

That is, grinding the columnar structure, reducing porosity, improving the conditions for capillary flow, etc.

The constructive implementation of the method is also difficult due to the difficulty of matching the waveguide-emitting system with the paired element due to the irregularity of the excited oscillations.

In addition, this method does not provide uniform heating of the joined elements during high-temperature soldering. For example, when induction brazing of the EV units, P with solder with a melting point of 1000 ° C, the temperature difference between the 15 connected surfaces reaches 1000 ° C or more (Fig. 1) due to the shielding effect of the surrounding element, which leads to the need for overheating of the outer surface in order to provide a capillary flow of solder, as well as the cost of time and quality of soldering.

The aim of the invention is to improve the performance and quality of soldering.

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To achieve this goal, in the method of soldering the telescopic joint, including the assembly of the male and female. elements, induction heating to the melting point of the solder with the effect of ultrasonic vibrations on one

of these, exposure and cooling, a static axial force is applied to the connected elements after assembly, ultrasonic torsional oscillations in the male element are excited, and when the solder melting temperature is reached, the intensity of oscillations is reduced by 3-10 times with subsequent removal of the axial force at the time of alignment temperatures of heated surfaces.

The uniformity of heating during induction brazing is an important aspect of the technological regime and affects the quality of the weld. The intensity of the ultrasonic vibrations in the first stage of the process provides for the preliminary heating of the male element and is chosen from the condition of equalizing the temperatures of the elements being connected.

Heating the solder before melting is performed by an inductor, which simultaneously heats both elements of the spa, but to varying degrees.

FIG. Figure 1 shows a combined graph of the heating of connected parts according to the proposed method, where pressure P (kg), temperature p (T ° C), current / (a) is indicated on the ordinate axis, time t (s) is on the abscissa axis. Curve / - pressure application graph; curve II is a graph of changes in the intensity of the ultrasound being excited; curve P1 - temperature dependence of the inner surface; kri.va IV - respectively, the outer surface; curve V is a graph of current variation in the inductor.

FIG. 2 shows a diagram of the implementation of the proposed method; in fig. 3 is a section A-A in FIG. 2

At the beginning of the process (/ o) force P (curve I) is applied, then intense torsional oscillations (curve II) are excited in the inner element of the parts to be joined, and internal heating (curve III) and external (curve IV) starts. details (section a). At time f2, a current is excited in the inductor (curve V) providing further heating (region c). At the same time, by the time point z, close to the melting point of the solder, the temperature of the surfaces being joined is equalized and the intensity of the ultrasonic effect is reduced. After the temperature has been equalized (time / 4), the pressing force is released and the shutter speed () is provided for the complete flow of solder over the entire cross section of the capillary. In this case, the current in the inductor and the intensity of ultrasonic vibrations provide isothermal holding and capillary solder flow.

The solder 1 (Fig. 2) is placed in the form of a ring on one of the connected elements 2 and 3. The heating of the connected elements is carried out using an inductor 4. Torsional ultrasonic frequency oscillations are excited in a detachable yoke 5 by two acoustic waveguides 6 excited by a magnetostrictive transducer mi 7, fed in antiphase. The compressive force P is created, for example, by a spring pressure material 8.

When soldering a batch in an amount of 10 brushes of 36NHTV stainless steel pipes with 10 steel bushings with a capillary gap of 0.08 mm using the proposed method with PMA solder having a melting point of 1083 ° C, the parameters are as follows: kg; Tue; Nz 1 w; where P is the static pressure, is the initial power of the ultrasonic oscillations; Ls - reduced power of ultrasonic vibrations; 30 s; 4-2-180 s; / 4- / s 10 s; t -, - - / 4-30 s; with.

When checking for vacuum density on the PTI-7A leak binder, all joints were vacuum-tight with a good filling of the capillary.

The use of compressive forces and torsional oscillations of varying intensity in the covered element during high-temperature induction brazing of extra-shells and EEC nodes provides the following advantages. Intensive excitation of regular oscillations in the melt of the solder when soldering the telescope | Ichesk and their connections is easily achieved. The destruction of the oxide film on the joining surfaces is greatly intensified, since the destruction occurs not only due to cavitation effects in the solder, but also due to the strength of the mechanical interaction that occurs during friction of parts oscillating with the frequency of regular torsional vibrations. The uniformity of the heating of the telescopic joint during induction brazing in connection with the additional heating of the male element due to pressing force and intense ultrasonic heating.

Formula kzobreten and)

The method of soldering the telescopic joint, including the assembly of the male and female elements, induction heating to those (solder melting points with the effect of ultrasonic vibrations on one of them, exposure and cooling, characterized in that, in order to improve the performance and quality of the soldering, to the elements being joined after assembly, a static axial force is applied, the ultrasonic vibrations of the torsional form SB are excited by the male element, and upon reaching the melting point of the solder, they reduce intensively vibrations be 3-10 times, followed by deprotection of the axial force at the time of alignment of Temperatures heated .vaemy 5 x surfaces

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tr The source of information taken into account in the examination: 1. From Nasa to you. The idea exchange - “Welding Engineer, 1967, No. II, p. 58-69 (prototype).

Claims (1)

Claim ) The method of soldering a telescopic connection ⁵⁵ , including assembling the male and female elements, induction heating to the melting temperature of the solder with the influence of ultrasonic vibrations on one of them, holding and 60 cooling, characterized in that, in order to increase the productivity and quality of soldering, to the connected elements After assembly, a static axial force is applied, ultrasonic torsional vibrations of the torsional shape of the covered element are excited, and upon reaching the melting temperature of the solder they reduce the intensity awn of vibrations 3-10 times with subsequent removal of axial force at the moment of equalization of temperatures of the heated surfaces. Source of information taken into account during the examination: 1. From Nasa to you, The idea exchan- 5 g _e - "Welding Engineer", 1967, No. II, p. 58-5g (prototype). FIG. 2 L-L fig.Z