RU2395802C1 - Method of ultrasound control over butt-welded seams - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: ultrasound shear oscillations are introduced and received. Oscillation source and receiver is moved along and across welded seam. Pour-like defects are detected and their size is determined. Distance from radiation source to revealed defects is measured. Defect depth and distance between defects are defined in the chain of defects in their depth allowing for diametre of the two greatest adjacent defects.

EFFECT: simple method of defining crystallographic texture.

3 dwg

Description

The invention relates to the field of ultrasonic quality control of welds, in particular to the control of thin welds with a limited width of the input surface of ultrasonic vibrations along the seams, and can be widely used in mechanical engineering and other industries.

A known method of ultrasonic scanning to obtain information about the quality of the weld along its entire thickness [1], including the conversion of electrical signals into acoustic energy and back acoustic energy into electrical signals, electronic scanning of an ultrasonic beam using phased arrays along the thickness of the weld, receiving reflected ultrasound signals from defects and converting them into electrical signals, by which an image of internal defects of the weld along its entire thickness is formed, is Busy Computer analysis of the detected defects is determined by their size and location of defects in the weld seam in three dimensions.

However, the method has several disadvantages:

- to implement the method requires complex, expensive flaw detection equipment and equipment;

- to implement the method and to work with the equipment requires highly qualified specialists;

- phased arrays for the implementation of the method cannot be used when limiting the width of the surfaces of the input-receiving ultrasonic vibrations along the weld;

- the method does not provide the quality of ultrasonic inspection of thin welds.

There is also a method of ultrasonic testing [2] for determining the diameter of spherical and cylindrical defects using shear ultrasonic waves, which consists in emitting an ultrasonic wave in the direction of the defect, receiving and analyzing the signal reflected from it, measuring the time interval Δt between the pulse reflected from defect, and the impulse obtained due to the bending of the defect by an ultrasonic wave during its double transformation on the surface of the defect, and the diameter of the defect is determined by the formula

- отношение скорости рэлеевской волны к скорости сдвиговой волны;Where

- the ratio of the speed of the Rayleigh wave to the shear wave velocity;

Δt is the time interval between pulses.

The specified method for determining the diameter of spherical and cylindrical defects in comparison with the previous method for obtaining information about the quality of the weld along its entire thickness has a clear advantage in that it does not depend on the thickness of the weld being controlled, does not require expensive flaw detection equipment, and is easy to configure.

However, the method has its drawbacks:

- it is intended only for determining the diameter (the magnitude of the detected spherical and cylindrical defects;

- does not determine the depth of the identified defects in the welds relative to the surface of the input-reception of ultrasonic vibrations;

- does not determine the minimum distances between defects (such as pores) in their chains along the thickness of the weld.

Despite the disadvantages, the method for determining the diameter of spherical and cylindrical defects is the closest in its implementation to the analogue of the invention and therefore is taken as a prototype.

The objective of the invention is to provide a method for ultrasonic testing of welds of small thickness with a limited width of the input surfaces of acoustic vibrations along them, providing a technical result, consisting in

- ultrasonic inspection of welds throughout their thickness;

- determining the depth of the detected defects;

- determining the minimum distance between two adjacent defects in their chain in depth.

This technical result is achieved by the fact that

- the distance from the defect to the radiation source of ultrasonic vibrations in the direction of the defect is measured:

the depth of the identified defects relative to the surface of the input-reception of ultrasonic vibrations is determined by the formula

where h _n is the determined depth of defects in the thickness of the weld relative to the input surface of ultrasonic vibrations;

L _n is the measured distance between the defects and the radiation source of ultrasonic vibrations (the input point of these vibrations);

α is the angle of entry of ultrasonic vibrations into the controlled object;

n is a natural number indicating the serial number of the defect;

- the minimum distance between the identified defects in their chain is determined by the thickness of the weld according to the formula:

where: ℓ is the determined distance between adjacent detected defects in the pore chain along the thickness of the weld;

L _n-1 is the measured distance between the defects and the radiation source of ultrasonic vibrations (the input point of these vibrations);

d _n is the diameter of the largest of two adjacent defects.

The proposed method is illustrated by drawings. In Fig.1 shows a diagram of a manual scan of an ultrasonic transducer along the seam, Fig.2 is a diagram of a scanning transducer with automated ultrasonic testing, Fig.3 is a diagram explaining the principle of operation of the proposed method. In figure 1, figure 2, figure 3: 1 - controlled weld, 2 - one welded part, 3 - the second welded part, 4 - ultrasonic transducer. In Fig.1: 5 - the trajectory described by the transducer 4 on the surface of the part 3, with manual ultrasonic testing. In Fig 2: 6 - the trajectory described on the surface of the part 3 with automated ultrasonic testing. In Fig.3: 7 - ultrasonic flaw detection equipment, n and n-1 - defects detected during ultrasonic testing, L _n and L _n-1 - the distances respectively between defects n and n-1 on the one hand and the input points of ultrasonic vibrations ( waves) on the other hand, h _n and h _n-1 are the depths of defects n and n-1, respectively, and ℓ is the distance between two adjacent defects n and n-1.

The method is as follows. Along the seam on the surface of the welded part 3, the transducer 4 is moved according to the manual scanning scheme 5 (see Fig. 1) or according to the automated scanning scheme 6 (see Fig. 2) at an angle a, ultrasonic vibrations are introduced into the part 3 (see Fig. 3 ) that pass through weld 1 and come back only if there is a defect. When a defect n-1 is detected, its diameter is determined, for example, by its reflectivity (by the magnitude of the maximum amplitude of the echo signal reflected from it) or by the prototype image. Remember the diameter of the defect n-1. Measure the distance L _n-1 (input points of ultrasonic vibrations in part 3) at the maximum amplitude of the echo pulse from the defect. The measurement result is recorded in the memory of the flaw detector 7. At the same time as the value of L _n-1 in the flaw detector, the depth of the defect n-1 in the weld is determined by the formula

по программе, заложенной в компьютеризированную дефектоскопическую аппаратуру 7.The result of the calculation is recorded in the memory of flaw detection equipment. If the defect is single, remember its parameters: the value of the equivalence of the defect (diameter) and the depth of its h _n-1 . If there is one more or a chain of defects in depth, the diameter of the next defect is determined, its value is stored, its distance to the source of ultrasonic vibrations (their entry points into part 3) is measured when the transducer is displaced to the weld 1 according to scheme 5 for manual scanning of the ultrasonic transducer 4 ( the input points of ultrasonic vibrations in the part 3). In the process of ultrasonic inspection of the weld 1 during transverse (across the seam) movement of the source of ultrasonic vibrations (transducer 4) after identifying a subsequent defect and performing operations to determine its parameters: the diameter, distance to the source of ultrasonic vibrations, the depth and memory they determine the distance between adjacent defects according to the formula

according to the program embedded in computerized flaw detection equipment 7.

In the process of automated ultrasonic testing of the weld 1, an operation to determine the pore chains containing at least two depths in each chain is introduced into the program 7 at the end of the control, consisting in the fact that all defects with all their parameters identified are combined in the process of control at the same coordinate along the weld 1. Then, according to the formula

according to the program embedded in computerized equipment, the shortest distance between each two adjacent depth defects is determined for each detected pore chain in depth.

The results of the inspection of the weld are printed out on a defectogram made in terms of the weld from the side of the input-receiving surface of ultrasonic vibrations and in the protocol of the results of the inspection, in which single defects are recorded with their parameters: diameter, depth, X and Y coordinates in the surface plane input-reception of ultrasonic vibrations and a chain of defects, where in addition to the parameters of the defects, the distance between adjacent defects of the chain is recorded.

Thus, the proposed method for ultrasonic testing of welds allows not only to determine the parameters of defects: their diameter and depth by thickness of the seam, but also the distance between adjacent defects in a pore chain stretched in depth (along the thickness of the weld), which allows more objective sorting of the weld.

Information sources

1. Shevaldykin V.G. and others. Look into the metal. Now it is easy. // In the world of non-destructive testing - No. 1 - 2008 - p. 46-53.

2. Auto USSR No. 615410, class G01N, publication date 06/08/1978.

3. Auto USSR No. 1146599, cl. G01N, publication date 11/23/1988.

4. Auto USSR No. 1165981, class G01N, publication date 02/01/1984.

5. Auto USSR No. 785743, cl. G01N, publication date 07/15/1977.

6. UK application No. 1572571, CL G01N, publication date 07/30/1988.

7. US Patent No. 4208916, cl. G01N, publication date 06/24/1980.

Claims (1)

The method of ultrasonic testing of butt welds throughout their thickness, including input and reception of shear ultrasonic vibrations, moving the source and receiver of these vibrations along and across the weld, identifying pore type defects, determining their magnitude, measuring the distance to detected defects from the radiation source, determining the depth of their occurrence and the distance between them in the defect chain in depth, while the depth of occurrence is determined by the formula:
h _n = L _n sinα,
and the distance between defects according to the formula:

where h _n is the determined depth of defects in the thickness of the weld relative to the input surface of ultrasonic vibrations;
L _n , L _n-1 - the distances, respectively, between defects n and n-1 on the one hand and the input points of ultrasonic vibrations (waves) on the other hand;
α is the angle of entry of ultrasonic vibrations into the controlled object;
l is the determined distance between adjacent detected defects in the pore chain along the thickness of the weld;
d _n is the diameter of the largest of two adjacent defects.

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