SU383555A1 - DEVICE FOR DETERMINING THE QUALITY OF A WELDED CONNECTION THROUGH THE HEAT EXPANSION VELOCITY - Google Patents

Description

one

The invention relates to a device for controlling the quality of a cast core according to the dilatometric effect and is intended to control and reject poor-quality joints in relief welding.

A device is known in which the quality of a welded joint is determined by the rate of thermal expansion of the metal. The device contains an electrode displacement sensor and a control circuit.

The proposed device differs from the known one in that its control circuit is implemented in the form of a serially connected differentiating unit, an assimilator limiter, a separation filter and contains a coincidence circuit, one input connected to a separation filter, and the other two - with a modulator and a synchronizer. the output of the coincidence circuit is associated with a light indicator and a generalization circuit.

Such an implementation ensures quality control and the rejection of poor-quality joints in relief welding.

The drawing shows a block diagram of the proposed device.

The device contains a block / sensor, a sensor 2 displacement of electrodes, a bridge circuit 3, a sound generator 4, a preamplifier amplifier 5, a detector 6, a differentiating unit 7, a limiting amplifier 8, a dividing filter 9, a W circuit, a modulator P, a synchronizer 12, light nap :: ctor 13, scheme 1-1 generalization n block 15 of the thread.

The device works as follows.

For the measured displacement of the electrodes, a block / sensor is used that contains a capacitance. The Hoii sensor is included in bridge circuit 3, powered by sound frequency generator 4. The unbalance voltage of the bridge is applied to the amplifier 5, the output of which includes the detector 6.

The external voltage, pronormal to the displacement of the electrodes, is sequentially differentiated 1, block 7, the output signal of which is the speed of the displaced electrodes, amplifier limiter 8 and section 1 cable 1.

At the output of the silicon limiter 8, rectangular pulses of positive polarity prn pushing apart electrodes and negative ones appear when they approach each other.

Filter 9 is used to detect parts that are not available for welding without reliefs. The recn welding to such parts is not prevented by the metal from expanding due to the current as a result of the deformation of the relief.

The duration of rectangular pulses during welding of such parts is more than that during the porous process of relief welding.

The filter 9 does not pass impulses, dlG: -; The capacity of which exceeds the first normal duration of the relief welding process.

From the filter 9, the signal arrives at the W coincidence circuit, which also receives signals from the modulator 11 from the synchronizer 12. The latter is controlled by the voltage of the welding transformer and outputs signals of positive polarity to the coincidence circuit. If the welding is of high quality (i.e. during the welding process, the electrode 5 is brought closer under the current and they move apart as a result of the metal expanding during the formation of the cast core), then during the control time, the circuit 10 coincides with the separation filter 9 with positive polarity signals, and the signal to Bbixo .:i, e of the circuit modulated by the modulator 11 ignites the light pdnkator 13. The results of the quality control of each one-point connection are summarized by the circuit 14, the signal from which is fed to the actuator connected to the welding typewriter. If all the joints of this product are welded qualitatively, then the control circuit permits welding of the subsequent product. Otherwise, it generates a signal for rejection of the welded product and blocks welding of subsequent products.

Subject invention

A device for determining the quality of a welded joint by the rate of thermal expansion of the metal, comprising a sensor unit and a control circuit, characterized in that, in order to control the quality and reject poor-quality joints in relief welding, the control circuit is implemented in the form of a serially connected differentiating unit, an amplifier-limiter separation filter connected to the inlet

a matching circuit, the other two inputs of which are connected to the modulator and the synchronizer, and the output to the light indicator and the generalization circuit;

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