SU1719980A1 - Acoustic tester to check the joint compressive stresses between a datum plane and shell conjugated to it at contact normal - Google Patents

Abstract

The invention relates to non-destructive methods of controlling contact stresses and can be used to determine the stresses at the abutment joint of a locking threaded joint of a drill pipe. Through one of the treated side surfaces of the envelope, for example a pipe, ultrasonic vibrations are introduced from the exciter at an angle to this surface, the exciter is moved in the direction perpendicular to the plane of the joint, the receiver’s position at which the signal is maximum is measured, the signal is measured in this position, the amplitude of the signal oscillations and the voltage ratio are determined from the ratio of the amplitudes. When implementing the method, standard flaw detector equipment can be used. (L

Description

The invention relates to ultrasonic means of control and can be used to control the magnitude of contact stresses in contiguous parts when assembling machines and mechanisms in drilling equipment, shipbuilding, and press building.

A known method of ultrasonic testing of contact stresses at the junction of the base plane and the envelope adjacent to it, consists in that through one of the side surfaces of the casing treated to a predetermined roughness from the exciter at an angle of this surface ultrasonic vibrations measure the amplitude of the oscillations output Through the same surface of the shell of the reflected ultrasonic signal and the measurement results determine the contact voltage at the junction.

The disadvantage of this method is the inability to establish a pattern of the distribution of contact stresses over the cross section of the joint, carried out normal to the lateral surface of the shell. The information on the distribution of contact stresses over the cross section of the joint allows determining the beginning of the elastic deformation of the coupling part of the threaded joint when the rational value of the joint tightening force is exceeded.

The purpose of the invention is to expand the technological capabilities of the control by determining the picture of the distribution of CO CO 00

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nor contact stresses along the cross section of the joint, conducted along the normal to the lateral surface of the shell.

A change in the pattern of stress distribution over the cross section of the joint indicates a change in the linear dimensions of the mating parts.

The goal is achieved by

that in the method of ultrasonic control of contact stresses at the junction of the base plane and the normal envelope adjacent to it, consists in that through one of the surface surfaces of the shell treated to a given value of roughness, the ultrasonic oscillations are inserted at an angle to this surface , the amplitude of oscillations of the reflected ultrasonic signal coming out through the same surface of the shell is measured, and the contact voltages in the joint are determined from the measurement results, the pathogen is moved in the direction , perpendicular to the plane of the junction, determine the position of the receiver adjacent to the position of the exciter and measure the amplitude of oscillations in the corresponding position of the receiver.

The drawing shows a diagram of the implementation of the proposed method.

The method of ultrasonic testing is carried out as follows.

Ultrasonic vibrations emitted by the exciter 1 are angled through one of the side surfaces of the shell 2 processed to a given amount of roughness and reflected from the junction 3 formed by the conjugation of the shell 2 and the base plane 4. The ultrasonic vibrations reflected from the junction 3 are taken receiver 5.

The proposed method includes the following basic operations.

excitation of a beam of ultrasonic vibrations;

the introduction of a beam of ultrasonic vibrations in a controlled area;

moving the driver in a direction perpendicular to the joint plane;

determining the position of the receiver adjacent to the driver position and measuring the amplitude of oscillations in the corresponding receiver position.

Loss of contiguous parts of the original shape under the influence of the load due to the appearance of elastic or plastic deformation leads

to the redistribution of contact pressures on the contact surface. The relationship between the magnitude of the contact pressure and the amount of reflected ultrasound energy (in this case amplitude) is linear and is described by the regression equation

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Where A A B + kp,

ultrasonic cores B, k

amplitude of oscillation;

contact pressure; regression equation coefficients.

For a frequency of 5 MHz, the equation takes the form:

A 21.63 + 0.06 p.

The magnitude of the deformation of the contacting parts is proportional to the difference in contact pressure on the contact surface.

According to the proposed method, the magnitude of the radial strain of the coupling of the locking threaded joint of the drill pipe was determined. Ultrasonic vibrations were excited and recorded using an ultrasonic flaw detector of type UD2-12. An ultrasonic sensor that excites a beam of pulsonic oscillations in the form of pulses with a filling frequency of 5 MHz was placed on the outer surface of the coupling part of the locking threaded joint 3-50, it also recorded the ultrasonic oscillations reflected from the threaded joint. The ultrasound beam was scanned by moving the sensor in a direction perpendicular to the plane of the joint. The flaw detector indicator observed reflected pulses from the upper and lower dihedral angles formed by the inner and outer surfaces of the conical groove of the coupling part of the joint and the thrust surface of the coupling. The magnitude of the amplitude of these pulses was carried out to the normalized value using the BP, H system of the flaw detector in the absence of contact pressure at the contact joint. When the threaded joint was tightened, the contact pressure at the stop joint increased, while the amplitudes of both pulses decreased in proportion to the increase in contact pressure. When the optimum torque torque (2000 N "m) of the locking thread is exceeded

connection between the 3-50 apulse reflected from the face angle, the onset and the amplitude of the pulse from the lower dihedral sting decrease. At the moment from 2000 to a meter of coupling in the plane ka increased by 0.4 mm, an increase in the amplitude of both signals occurred to an increase in the size of the coupling.

Thus, the strain value in this case was determined as the difference between the maximum and minimum values of the signal amplitudes, and the correction for the attenuation of the signal was introduced when the distance of the sensor was changed from the insertion point to the interface.

The proposed method is simple and affordable, with its implementation, you can use the standard flaw detection equipment.

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Claims (1)

The invention of the method of ultrasonic testing of contact stresses at the junction of the base plane and the normal conjugate shell is that through one of the side surfaces of the shell processed to a given value of roughness, ultrasonic vibrations are introduced at an angle to this surface, the amplitude of oscillations of the reflected ultrasonic signal going out through the same surface of the shell is measured, and the contact voltages at the junction, which differ from o, in order to expand technological capabilities by determining the pattern of stress distribution over the cross section of the joint, carried along the normal to the lateral surface of the shell, the pathogen is moved in the direction perpendicular to the interface plane, the receiver position is matched with the exciter position, and the amplitude of oscillations is measured in appropriate position of the receiver.