SU759265A1 - Contact-welding quality control method - Google Patents

Description

The invention relates to the field of resistance welding and can be used to control the quality of welding joints in the process of their 5th execution.

There is a method of quality control of contact welding of compounds, which consists in the fact that the quality of welded joints is determined by the amount of movement of the moving electrode I.

To assess the quality in a known way is the installation of the top. and lower limit values (i.e. tolerance fields) for moving the moving electrode;

The disadvantage of this method is the erroneous rejection of a significant number of welded joints in those cases ... ,. when a splash appears in the process of making welds. The splash, as is known, is accompanied by the removal of a part of the liquid metal from the welding area, as a result of which: $ moving the mobile electrode pre? the upper limit is set, and the connection is rejected. At the same time, for many open-type compounds, small splashes are permissible,

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welding quality is considered satisfactory.

There is also known a method of quality control of contact welding, mainly of small open-type joints, in which the quality of welding joints is determined by comparing the magnitude of the displacement of the movable. electrode with shrinkage of the metal after welding with a given value (2].

The disadvantage of this method is the low accuracy of the quality control of the welded joint, which is caused by monitoring only the movement of the moving electrode without taking into account the change in resistance in the interelectrode area during welding.

The purpose of the invention is to improve the accuracy and quality control of the welded joint directly in the process of welding.

Delivered. The goal is achieved by measuring the voltage in the interelectrode zone before comparing the amount of movement of a moving electrode with a given value, comparing the measured value with the reference voltage, if the measured voltage is 759265

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[increases the reference, increase the specified value of the displacement of the moving electrode.

The voltage is measured on the parts to be welded, and as the reference voltage, the maximum amplitudes are assumed to be of great value during the no-splash welding process. .

FIG. 1 shows the timing of the movement of the moving electrode? in fig. 2 - timing diagram of the voltage drop measured on the parts to be welded.

Curve 1 is characterized by the displacement X of the moving electrode during the no-blow process, curve 2 is the same when a splash appears, curve 3 is 15 voltage 11 on the dividers. On the horizontal axes, the time ϋ is plotted.

The x'pred level corresponds to the ultimate displacement of the movable electrode in the no-flash process, the level Hdred “also in the presence of splash. Level II _op is the maximum voltage during a no-splash process.

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The quality control of joints in the process of welding is carried out as follows.

The control starts with measuring the voltage соедин on the connected parts in the interelectrode zone. Then it is compared with the reference voltage level ’

this, if this voltage does not exceed ϋ _οη , then the quality of the welded _ connection is judged by the amount of displacement X of the moving electrode, comparing it with the given value x'pred · ⁱⁿ this case welding takes place without a splash of liquid metal (curve 1). 40

If the measured voltage O ka of the parts to be welded exceeds the voltage ϋ _οη , then this indicates the appearance of a bulge. The displacement, X of the moving electrode in this case occurs on curve 2.

Comparison of this movement is carried out with an increase in AH value of x £ p _in d · If you do not make adjustments to the limit value, then the welded joint corresponding to curve 2 will be classified as rejected.

The choice of the level of the reference voltage and _Op , with which the measured voltage П is compared, is made on the basis of the magnitude and form of the voltage drop across the measured area in the area of the electrode. For example, in some welding processes with a splash, the welding current may decrease ds zero. Voltage 60 in this case reaches values close to the no-load voltage, i.e. exceeds the amplitude value of the voltage when welding without welding. Therefore, as a reference voltage

a voltage equal to or slightly higher than the amplitude value of the voltage during free-splash welding is taken.

The choice of voltage pickup points determines the accuracy of measuring it. The most accurate voltage measurement is achieved by placing the probes on the parts to be welded.

The quantity dX, which increases a predetermined limiting value x _'pre d the movable electrode during welding splash determined empirically.

The control method was tested during butt welding of copper-aluminum leads of electrolytic capacitors. Diameter, conclusions less than 1 _MM . Welding was carried out on the welding machine UB — 544. Experimental work has shown that this method allows the selection of welded joints with high accuracy. This significantly reduces the waste of welded joints in the marriage, at the same time, experimental work has shown that this method is most effective when welding small open parts.

Claims (2)

Claim 1. The method of quality control of contact welding, mainly small * open-end dimensional joints, in which the quality of welded joints is determined by comparing the displacement values of the moving electrode during shrinkage of the metal after welding, with a given value, In order to improve the accuracy of the quality of a welded joint directly in the welding process, before comparing the displacement of a moving electrode with a given value, measure the voltage in the interelectrode zone and compare it with the reference voltage, while the measured voltage exceeds} / reference, increases the specified amount of movement of the moving electrode, 2, Quality control method for contact π welding. The first is that the stresses are measured on the parts to be welded, and the maximum value of the stresses is taken as the reference voltage during the flame-free welding process. Sources of Information taken into account in the examination 1. USSR author's certificate "241563, cl. In 23 K 11/24 1968 (prototype). 2. Orlov B.D., Chuloshnikov P.L., Verdensky V.B. and Marchenko A.Ya. Control of spot and roller electric welding. M., * 'Mechanical Engineering *', 1973, with. 202-225. 759265 '