JPS6120675A - Manufacture of two-point welded coupling section, particularly, manufacture of current pull-in section of bar,foil and bar mold, which is pressure-sealed in hard glass orsilica glass and has high melting point - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for making joints, and in particular to said method applied in the production of current leads in the form of bars, foils, or rods sealed in hard glass or quartz glass and having a high melting point.

The current draw, which is generally made of molybdenum or tungsten and has a high melting point, is mounted using a molybdenum foil bordered in a flat part of hard glass or quartz glass, according to widely known technical methods; That is, the rod-shaped current lead-in is connected to the end of the molybdenum foil, in particular by resistance spot welding, in such a way that the electrical power is guaranteed. This method must ensure an airtight construction.

The above-mentioned constructional solution is quite complex and therefore poses technical difficulties. That is, it is difficult to weld the materials that are to be welded together. The difficulty of the welding process is, first of all, that there are large differences in the dies (the diameter of the rod-shaped current lead-in part is Q, 4 mm to 1 mm, and the thickness of the foil is 0.02 am to 0.0 mm).
5 fin), and secondly due to uncertainties in the surfaces that touch each other. With such uncertainties, the genera of the surfaces in contact with each other becomes progressively wider during the welding process. Furthermore, due to the large difference in thermal expansion coefficient between glass and molybdenum or tungsten,
A problem arises in that large mechanical stresses occur during the manufacture of the lamp, especially when the lamp is energized and de-energized. The foil breaks due to the mechanical stress created in the flat area,
This results in the disadvantage that the foil recrystallizes in the heat-effect zone of the weld.

In order to avoid such recrystallization in the thermal region, platinum,
Solutions are known in which metallic intermediate parts, such as tantalum, are used, ie the use of such intermediate parts in order to reduce the temperatures required for the production of the composite. By such measures the temperature during the welding process is significantly reduced and recrystallization is avoided. This is because the foil is not overheated in the welding area. It is also known to reduce the size of the molybdenum particles in the foil and to use corresponding alloys, which makes it possible to increase the recrystallization temperature.

According to another known method, a current inlet previously sealed in the glass is mounted in the flat part. This solution is applied in place of rod-foil-rod configurations, especially in long-life light sources.

Additionally, at least one suitable bonding glass is used;
This bonding glass allows stress-free mounting of the high melting point current lead into the quartz glass.

A common disadvantage of the above-mentioned known methods is that they require additional work to prepare the coating or the alloy or the intermediate parts, which leads to a significantly higher consumption of material. There is.

The purpose of this light is to remove the light from the ground, especially in flat areas.
The current drawing part has a foil-bar type structure.
+i Can be applied to production, taking into account the quality of the lamp, in order to obtain a high-quality joint, without the need for intermediate parts in the foil, or by glass-sealing the current lead-in part. It is an object of the present invention to provide a welding method that does not require any problems.

Since the load capacity of conventional linear spot welded seams is unfavorable, it seems desirable to change the shape of the welded seam. This is because, in known fused joints, the high heat that melts elements with high melting points, including molybdenum and/or tungsten, during welding causes recrystallization of the heated regions. .

When creating weld seams with large surfaces, recrystallization occurs over the entire cross-sectional area of the thin foil, resulting in gaps at the grain boundaries during the processing process, making it impossible to use it in light source technology. Become.

Taking into account static and dynamic loads, the shape of the seam favorable to these loads can be determined on the basis of the tensile tests resulting from the action of these loads. this is,
This is because the allowable H ratio of tensile stress and shear stress is equal to the ratio of the elastic module of the Camolybdenum foil, and when the load capacity required for shearing and tearing is pure shear, the loss is almost 6 times higher. (The elastic module of molybdenum is E = 3.4 x 105N/mm2, G = 'L
2.8 x 105N7mm2). Therefore, if the longitudinal length of the weld seam is increased, a large amount of thermal energy has to be introduced, increasing the risk of recrystallization, while the static load capacity of the joint remains almost unchanged, and at the same time the dynamic The physical load capacity shows a significant decrease as it becomes difficult to change the shape.

The above recognition can be verified in many ways by technical research and tensile strength tests.

Based on this recognition, it can be considered that it is appropriate to apply two-point welding in order to determine the cross-sectional area of the joint required for welding the current lead-in portion. The static and dynamic load carrying capacity of such a connection is satisfactory and the form of the dotted weld seam is ideal.

This is because the welded seam is almost circular in cross section,
This is because the length of the seam area required for shearing and tearing is doubled. The permissible load values per length unit are thereby very favorable. In this way it is possible to ensure the avoidance of recrystallization, so that the strength of the seam is approximately equal to the strength of the basic material.

German patent publication no.
It is publicly known from the 6υ publication. The foil is cut transversely, and a portion of the current draw is fitted below the foil, a pond portion of the current draw is placed above the foil, and the two sections are brought together by resistance welding. A current drawing portion is formed by the slit. In this way, one welding point is created at the top and bottom of the upper resistance welding electrode between the bar-shaped current lead-in and the foil.

The disadvantages of this solution are that the strength of the foil is reduced and that the weld points are formed on different planes, resulting in a reduction in the load capacity of the two-point joint.

Another disadvantage is that it is mechanically difficult to insert the rod-shaped current lead into the slit under the conditions of large-scale production, and it is difficult to accurately adjust the distance in the foil, so the welding point It is not possible to make the arrangement symmetrical.

Swiss Patent No. 545163 discloses a non-contact system for inspecting the welding position generation process during resistance welding. In this invention, the signal of a detector (phototransistor) known per se with infrared radiation is used.

During the welding process, the intensity of the infrared radiation in the vicinity of the welding electrode is measured, thereby making it possible to observe the temperature required for welding. When the signal, which is proportional to the heat radiation of the surface, reaches a minimum level, a quality grade corresponding to the welding position is added.

The disadvantage of this solution lies in the use of optical systems that require very precise color filtering. In this case disturbance signals and noises from a series of ponds are filtered out.

The object of the invention is to further improve the method of two-point welding and to eliminate the drawbacks of the welding methods and the iQ-decision methods of inspection known from the prior art. The invention is based on the recognition that foils can be automatically inspected if a specially configured electrode is used for resistance welding to connect a rod-shaped current draw to one side of the foil. .

In order to solve the problem mentioned in item 1, a method was proposed for making two-point welded joints, which in particular involves the use of high melting point foils, sealed in hard glass or quartz glass. Application is made to the production of rod-shaped current leads, the welding points forming the joint being made by resistance welding, and according to the invention, the two-point joint is formed by using only one tube electrode. It is produced at least on one side of the foil at the technical stage.゛The hole diameter of the tube electrode used for resistance welding is 05 to 15 times the diameter of the current drawing part, discharge electrode, or incandescent coil.
By doubling it, the conditions for heat transfer can be influenced advantageously.

The quality of the manufactured joint can advantageously be checked indirectly in European fashion, i.e. by detecting the temperature radiation of the surface of the foil around the joint to be manufactured during the welding process and In order to generate and detect a post-processable signal, a suitable detection element, such as a first detector, can be placed in the opening of the tube electrode and tested.

In the case of bulk production, the signal of the detection element can be used to control the selection of incorrectly welded current draws. This signal is also suitable for creating a system for regulating the welding process.

The method according to the invention will now be explained using illustrated embodiments.

A current drawing unit is illustrated in FIG. The current drawing unit is arranged in a quartz glass flat part of the high-pressure discharge lamp.

The current-feeding unit has a current-feeding part 1 and a foil 2, the foil 2 being connected to the current-feeding part 1 and the discharge electrode 6 at a connection point 5. The quartz glass flats 4 have foils 2 between the joining locations 5, thus ensuring a gas-tight closure.

According to FIG. 2, the current drawing part 1 and the incandescent coil 6 are connected to two
It is connected to the foil 2 by a point connection 7. Due to the two-point connection 7, the surface of the current lead-in portion 1 or the surface of the straight portion of the incandescent coil 6 that comes into contact with the surface of the foil 2 does not become large. This is because the geometry of the seam is favorable, i.e. approximately circular;
This is evidenced by the fact that it is possible to guarantee the necessary connection cross-section in terms of load capacity and current draw.

The two-point connection 7 is created with a single technical measure, so that no shunt effects occur that limit the distance between the connection points.

The two-point resistance welding method according to the invention is realized, according to FIG. 3, by using a tube electrode 8 when creating the two-point joint of the current lead-in section.

In the case of resistance welding, thermal energy is generated at the welding point and the surface to be welded is in contact with the tube electrode 8. In order to equalize the strength of the joint, the pressure exerted by the tube electrode 8 must be equal at both weld points. This is achieved by the symmetry of the tube electrode 8, which allows in one step the shape of the welded part to be approximately circular, ie favorable with regard to strength.

Furthermore, a welding electrode 10 is joined to the tube's electrode 8, and by this joining it is possible to form a seam of equal quality at both welding points.

In order to weld and connect the current lead-in part 1 and the foil 2 at two separate points by resistance welding, the tube electrode 8 is provided with a hole, the diameter of which is larger than the "IG" of the connection location 5. .

The invention makes it possible to easily control the size of the weld point and the strength of the bond. In the case of a method of two-point resistance welding, in particular a method that takes into account the possibilities offered by the configuration of a rod-foil-rod current-drawing unit and the advantages of the method according to the invention, for creating a current-drawing combination. It is proposed to use a two-duct resistance welding device, in which case one
The temperature changes that occur during reheating are observed after two welding cycles. For this observation, the temperature radiation of the surface of the foil between the two welding points is utilized, and the detection of the temperature radiation is
It is used as a basis for determining whether the weld point has the required size.

For this purpose, a photodetector 9 is integrated into the bore of the tube electrode 9, which photodetector 9 is used to detect the temperature radiation on the surface of the foil 2. If the welding point is of the desired size, the contact resistance is reduced and the reheating impulse (the duration of which does not exceed half a cycle) does not significantly heat up the surroundings of the spot weld seam. By comparing the detected or experimentally determined level of the signal amplitude, defective joints can be singled out, thereby affecting the quality of the weld seam during resistance welding. It is possible to exclude accidental effects due to various variable components that give .

At the same time, it is also possible to install only those electrical units that meet the desired quality requirements for subsequent technological steps. The measurement results are also used to control or adjust technical parameters of the welding process.

In order to illustrate in detail the two-point resistance welding method according to the invention, some examples will be described below.

Example 1 A current lead-in part 1 of a high-pressure gas discharge lamp with a diameter of 06 mm was welded to a foil 2 with a thickness of 22 μm.

A pair of tube electrodes 8 was used for this purpose. The tube electrode 8 has an outer diameter of 3+++m and a hole diameter df of 1rnm. Tube electrode 8
has an insert made of tungsten by sintering. Welding was carried out for one cycle, using a 50 Hz secondary alternating current voltage of 2 V and an electrode force of 100 N.

No recrystallization was observed in the hot region of welding. Tear resistance tests of the joints showed that the shear and tearing forces were 40% lower than joints welded by conventionally known methods.
% high two-point joint 7 was obtained.

Example 2 The discharge electrode 3 of a high-pressure discharge lamp is 1 or 2 inches in diameter and has a thickness of 25 mm.
Welded to the μm foil 2. For this reason, the outer diameter is 3
A tube electrode 8 with a hole diameter df of 1.51 nm and a diameter of 3
A welding electrode of 10 mm was used. The tube electrode 8 has an insert which is sintered from tungsten.

Applying the tube electrode 8 only on the side of the foil 2 for welding,
The welding electrode 10 at the current drawing part 1 is
It turns out that a tungsten rod that can be cut is sufficient.

Example 3 A detector 9 for detecting temperature radiation was placed in the internal space of the tube electrode 8. As the detector 9, a photodiode or a phototransistor can be used. A detector 9 was installed to detect the intensity of the temperature radiation measurable around the following points on the foil 2, namely on the axis of the hole in the tube electrode 8:

The photodiode is sensitive to wavelengths representing thermal radiation above 100° C., and as the temperature increases, it produces a photocurrent that increases sharply in a relatively high temperature range. The intensity of this photocurrent is proportional to the temperature radiation.

Various circuit technology solutions are known that are suitable for recording the signal obtained by the intensity of the photocurrent.To detect the thermal radiation, a phototransistor of type 0813 was used. The photocurrent of this phototransistor is
TEK'll'RONIX 70 in the form of a proportional signal while the test impulse is used for post-welding heating
It was stored using a 00 type memory oscillator. Therefore, the photocurrent was recorded by the corresponding signal. In this way, changes over time in thermal radiation of the foil portion observed during reheating performed after welding were measured. Furthermore, the magnitude of the reheating photocurrent signal was determined experimentally in response to individual values of the weld seam strength.

For example, the output signal proportional to the photocurrent of the measuring device we used is less than 2■ if the weld seam is in good condition.

It has been found that there is a favorable correlation between the magnitude of the photocurrent signal and the shear friction force measurable at the two-point joint 7. This output signal is suitable for supplying an input signal to a circuit for the regulation and/or control of technical parameters in the production of two-point welded connections, in particular during lamp production.

The maximum value of the photocurrent belonging to the test impulse (reheating) is determined in advance, and a method for selecting defective parts is set up based on this maximum value. If this is done, the reliability of the method according to the invention can be increased, especially when manufacturing lamps by applying the two-point resistance welding method proposed by the invention, the technical reliability of the manufacturing can be increased. can be increased.

In order to confirm the above, two types of samples of 20 pieces each were prepared by welding. In this case, two strips in each sample exhibited photocurrents exceeding the determined maximum value. Sample tear strength tests were conducted at each joint. Even in the absence of the above two defective members, the average value and deviation of the shear tensile force were determined according to this strength test. υ[tension is 2
There was a slight increase of about 6% after removing the that time,
It has been found that the bias in measured values can be improved to a considerable extent. In other words, the deviation of the shear tensile force is 5 for one sample.
．． 1 N to 2.56 N, other sump) V at 5
．． It decreased from 2N to 254N.

Based on these measurement results, it was possible to determine the size of the welded seam by '76 (J).In other words, a selection method that uses a predetermined value of photocurrent belonging to high-quality welded seams as a selection criterion is
It is suitable for ensuring uniformly high quality joints. In this case, it is possible to make use of the possibilities offered by the construction of the current feed-in, ie a heating test of the foil during welding, and possibly an overheating test. In the two-point welding method according to the present invention, the two-point joint during the welding process can be considered as follows.

That is, the thermal radiation of the foil region lying on the axis of the bore of the tube electrode 8 is detected during electrical reheating, thereby making it possible to control the size of the two-point joint 7 obtained by the welding process. It is.

The method according to the invention is suitable for producing high-quality joints in mass production, with the possibility of automatically checking whether quality requirements are met.

4 drawing t4? i j,)i Description Figure 1 is a perspective view of the current lead-in part sealed in quartz glass, Figure 2 shows the current lead-in part filled with halide, manufactured by two-point resistance welding. FIG. 3 is a plan view of the flat part of the light source, illustrating one embodiment of the method according to the invention in manufacturing the current lead-in part of FIG. 2;

1. Pa-Kame-ryu drawing part 2...Foil 3...discharge electrode 6...Incandescent coil 7...2-point joint 8...Tube electrode 9...Photo detector

Claims (5)

[Claims] (1) A method for manufacturing a two-point welded joint in which a rod-shaped current-drawing element is joined to a foil at two points by resistance welding, in particular a rod with a high melting point sealed in hard glass or quartz glass. - In a method for producing a foil-rod type current lead-in, the two-point connection (7) is connected in one technical step to at least the foil (2) by applying a tube electrode (8). A method characterized by being made on one side. (2) The hole diameter of the tube electrode (8) used for resistance welding is 0.5 to 1.5 times the diameter of the current drawing part (1), discharge electrode (3), or incandescent coil (6). 5. A method according to claim 4, characterized in that: (3) the quality of the weld seam by detecting the temperature radiation on the surface of the foil (2) around the two-point joint while applying a test impulse that is used after the welding process and causes reheating; tube electrode (8) to indirectly control during welding and transmit a signal proportional to the temperature radiation
Claim 1 or 2, characterized in that a photodetector (9) is used which is arranged in the hole of the
The method described in section. 4. Method according to claim 3, characterized in that the signal of the photodetector (9) is used as a control signal for selecting a defective weld joint. 5. Method according to claim 3, characterized in that the signal of the photodetector (9) is used for regulating the welding process.