RU2589456C1 - Method for nondestructive inspection of cast structural parts - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention can be used for non-destructive testing of cast parts. This invention consists in fact that sector scanning PAA sensor is performed by rocking beam with simultaneous movement of PAA sensor control at the site at first in transverse, and then the longitudinal plane in forward and reverse directions, wherein direction of movement of the PAA sensor is in plane of swinging beam is automatic recording of results of ultrasonic inspection together with recording of coordinates of movements of PAA sensor on surface section control by means of analysis of recorded data for each input angle sector of scanning coordinates of PAA on surface area of control, in which amplitude of echo-signal exceeds level of fixation of echo-signal amplitude corresponding to defect at the found coordinates on surface area of control and taking into account input of scanning sector angles for each coordinate, on which is defined by maximum amplitude of echo-signal, coordinates of points in section castings with amplitude of echo signal exceeding level of fixation. At that, conditional defect length is defined as distance between extreme positions of projection of certain points on scanning plane.

EFFECT: technical result is upgraded reliability of detection of defects of moulded structural articles.

1 cl, 4 dwg

Description

The invention relates to the field of non-destructive testing methods for molded body parts and is intended for both primary inspection of foundry products and control of products in operation. In the particular case of the claimed invention can be used for non-destructive testing in the manufacture of bodies of main pumping units.

The following defects are characteristic of cast hull products: pores, shells, loosening, cracks, inclusions. Pores and shells have scattering directrixes close to circular. Plane defects (including cracks) have pronounced directional scattering directrixes, which leads to the difficulty of their detection by ultrasonic control methods. To reduce the probability of missing defects, domestic standards [GOST 24507-80 Non-destructive testing. Forgings from ferrous and non-ferrous metals. Methods of ultrasonic flaw detection] recommend conducting ultrasonic testing (ultrasonic testing) with sensors having a normal input angle (0 degrees to the vertical to the control surface, Fig. 1), as well as an inclined sensor with one fixed input angle. Moreover, the control of the inclined sensor is made in four mutually perpendicular directions. With ultrasonic testing of complex cast products, such as pump housings, these recommendations do not always allow reliable identification of defects with an arbitrary orientation.

A known method of ultrasonic testing [patent application JP 2001343370 A, publ. 12/14/2001, IPC: G01N 29/22, G01N 29/30, G01N 29/44]. The known method is aimed at developing an ultrasonic inspection method capable of performing flaw detection of material objects having a coarse crystalline structure, such as sections of metal welds, cast products, etc. Data depending on the angle of incidence is obtained by performing a flaw detection of the test sample by changing the angle of incidence of the ultrasonic wave, and then data on the weighted functions based on the data of the dependences of the angle of incidence are obtained. Frequency dependency data is obtained by performing flaw detection, by transmitting an ultrasonic wave having a frequency band, or the like, and data on weighted functions is obtained from the frequency dependency data. Flaw detection is performed with the actual inspection of a material object by changing the angle of incidence of the ultrasonic wave, and the weight is set by the data on the weighted functions. To obtain actual flaw detection data, flaw detection is performed by an ultrasonic wave having a frequency band to improve the signal-to-noise ratio and detect a defect. The angle of incidence is changed using the phased array method, and the frequency band is expanded using a probe equipped with a composite type piezoelectric transducer.

The closest analogue of the claimed invention is a method for detecting the inclusion of heavy alpha particles in titanium castings [patent application WO 0171337 A1, publ. 09/27/2001, IPC: G01N 29/04, G01N 29/06, G01N 29/26, G01N 29/265], in which non-destructive testing of a mesh or close to mesh shape casting based on titanium obtained by investment casting is performed for which scans the inner space of the casting under its outer surface using ultrasonic waves formed by a phased array (PAR) to control the inclusions of alpha particles randomly located inside the casting, shells formed during the casting process, and other inclusions present in the microstructure that cause cracking castings. The method is most useful and has advantages in relation to the detection of inclusions of alpha particles in the microstructure of areas critical to the destruction of structural housing castings based on titanium, obtained by investment casting.

The disadvantages of the closest analogue include carrying out a scan according to the known method in such a way that the casting zones are not sounded in the entire maximum possible range of input angles, as well as the lack of a method for assessing the conditional dimensions of extended defects using scan data.

The task to which the claimed invention is directed is to increase the reliability of control of molded hull products.

The technical result is to increase the reliability of identifying defects in molded hull products, which reduces the probability of missing dangerous defects that reduce the strength of molded hull products.

This problem is solved, and the technical result is achieved by the fact that the method of non-destructive testing of molded body parts includes the steps of breaking the surface of the molded body parts into control areas and applying contact lubricant to them, performing ultrasonic scanning of selected sections of the molded body parts according to the transverse-longitudinal scheme phased array sensor (PAR) movement: perform sector scanning with the PAR sensor by swinging the beam while moving the PAR sensor on an hourly basis first, in the transverse direction, and then in the longitudinal plane, in the forward and reverse direction, the direction of movement of the HEADLIGHT sensor being carried out in the beam swing plane, the results of ultrasonic testing are automatically recorded together with the recording of the coordinates of the HEADLIGHT sensor on the surface of the control section, by analyzing the recorded data for each angle of input sector scan find the coordinates of the PAR on the surface of the control section, in which the amplitude of the echo exceeds the level of fixation the amplitude of the echo signal corresponding to the defect according to the coordinates found on the surface of the inspection site and taking into account the input angles of the sector scan for each coordinate at which the maximum amplitude of the echo signal is determined, determine the coordinates of the points in the section of the casting with the echo amplitude exceeding the fixation level moreover, the conditional extent of the defect is defined as the distance between the extreme positions of the projection of certain points on the scanning plane.

The claimed invention is illustrated by drawings (Fig. 1-4), which depict:

FIG. 1 is a diagram for determining the conditional extent of a defect in conventional ultrasonic testing;

FIG. 2 - ultrasound scanning of the selected areas of the molded body parts according to the transverse-longitudinal scheme;

FIG. 3 - sector scan: a) transverse wave control,

b) longitudinal wave control;

FIG. 4 is a diagram for determining the conditional extent of a defect.

To control cast hull products, flaw detectors with ultrasonic phased arrays included in the sector scanning mode (i.e., with a varying input angle) are used. Scanning is performed in the longitudinal direction of the sensor along the plane of the beam swing. Thus, the same defect is fixed at different angles of input of the ultrasonic signal. This method is applicable both for monitoring through flat and cylindrical surfaces, and at radius transitions.

Application of the above scanning method makes it possible to determine the equivalent area of the reflector (non-extended defect) with a large number of input angles, and also allows:

- assess the type of defect - volumetric or planar;

- evaluate the directivity and width of the scattering directrix, which makes it possible to evaluate the orientation of a planar defect;

- for defects whose size is larger than the width of the radiation pattern of the ultrasonic beam, it becomes possible to determine its equivalent dimensions, to evaluate the shape and position of the boundaries of the defect.

The claimed method of non-destructive testing of molded body parts is as follows.

Initially, a flaw detector is tuned with ultrasonic phased arrays, which provides the required control sensitivity. The adjustment is carried out in such a way that the condition is met under which for all defects having the same equivalent area, the same echo amplitude will be obtained in the entire control range.

After setting up the flaw detector, the surface of the cast body part is prepared to ensure that its surface roughness corresponds to the values suitable for ultrasonic scanning. The standard value of the surface roughness of the product for ultrasonic testing (ultrasonic testing) is Rz-40. To control the surface of cast steel products, a roughness value of Rz-80 or more is allowed. The surface preparation of the cast body part to comply with this requirement is carried out by sandblasting, shot blasting or the like.

Break the surface of the molded case into control sections. The number and sizes of control sections are selected depending on the complexity of the surface of the molded body part. Contact lubricants are applied to the controlled surface areas to ensure the transmission of the ultrasonic signal from the sensor directly to the product.

An ultrasound scan of the selected areas of the molded body parts according to the transverse-longitudinal scheme (Fig. 2). When scanning, a phased array sensor (PAR) performs a sector scan by swinging the beam while moving the PAR sensor along the scan lines. The swing plane of the HEADLIGHT beam must match the direction of movement of the sensor. Scanning of the control section is carried out in four perpendicular directions: in two mutually perpendicular directions during control by longitudinal waves (Fig. 2 a) and c)) and in two perpendicular directions during control by transverse waves with scanning in the forward and backward directions (Fig. 2 a) b) c) and d)).

When controlling the transverse wave and sector scanning, the movement of the headlamp sensor is shown in FIG. 3 (a). The range of "swing" of the beam is set in the range + 40 ... + 75 degrees (a deviation from the specified range is possible, taking into account the specifics of a particular control object), respectively, the defect is "voiced" in the entire specified range of input angles. When scanning in the opposite direction, the range of scanning angles is -40 ... -75 degrees. When monitoring with a longitudinal wave, the movement of the PAR sensor is shown in FIG. 3 (b), the range of "swing" of the beam can be, for example, -45 ... + 45 degrees. Thus, the defect is voiced in the maximum range of input angles, which increases the likelihood of its detection.

In the process of scanning, an automatic recording of the results of ultrasonic testing is carried out together with the recording of the coordinates of the displacement of the PAR sensor on the surface of the control section. For precise reference to the coordinates on the surface of the control section, scanning is performed using a path sensor. This recording mode allows you to determine at what angle of input the amplitude of the echo signal is maximum for each section point of the monitored object. Knowing the dependence of the amplitude of the echo signal reflected from the surface of the defect on the location of the PAR sensor allows you to evaluate the shape of the surface of the defect: volumetric, planar, and its orientation in the body of the molded part.

Analysis of the recorded data is carried out as follows. 1. Find the set of coordinates of the PAR sensor on the surface of the control section, on which the amplitude of the echo exceeds the level of fixation of the amplitude of the echo corresponding to the defect.

2. For each of the found coordinates of the HEADLAMP sensor, on the surface of the control section, find the angle of ultrasonic wave input at which the value of the echo signal from the defect is maximum (Fig. 4).

3. Given the found coordinates of the PAR sensor and the angles of input of the ultrasonic wave at these coordinates, the coordinates of the points in the cross section of the cast part with the maximum values of the echo signal from the defect are determined.

4. The magnitude of the conditional extent of the defect is defined as the distance between the projections of the extreme points with the maximum value of the echo signal in the cross section of the cast part on the control surface (points X1 ′ and X3 ′ in Fig. 4).

The conditional extent of the defect is defined as the distance between the extreme positions of the projections of the found points in the section of the part onto the scanning plane according to formula (1).

where a is the conditional length;

X1 and X3 - extreme position of the PAR sensor with a decrease in the echo signal to the level of fixation;

α1 is the input angle at the maximum value of the echo signal from the defect in the position of the HEADLAMP sensor at point X1;

α3 is the angle of entry at the maximum value of the echo signal from the defect in the position of the PAR sensor at point X3;

L1 is the distance along the beam from the surface to the reflection point on the defect at the maximum value of the echo signal from the defect in the position of the HEADLAMP sensor at point X1;

L3 is the distance along the beam from the surface to the reflection point on the defect at the maximum value of the echo signal from the defect in the position of the HEADLAMP sensor at point X3;

X1 ′ is the value of the X coordinate of the point of maximum echo from the defect in the position of the HEADLAMP sensor at point X1;

X3 ′ is the value of the X coordinate of the point of maximum echo from the defect in the position of the HEADLAMP sensor at point X3.

To determine the shape and conditional dimensions of the found defect, scanning and determination of the conditional extent of the defect are carried out in all four perpendicular directions.

Example.

Ultrasonic testing of the cast body part-flange was carried out, the surface of which was divided into control sections 300 × 100 mm in size. Gel contact grease was applied to the controlled surface areas. Next, an ultrasonic scan was carried out with a direct phased array sensor of selected areas of the cast body part according to the transverse-longitudinal pattern. When controlling the transverse wave and sector scanning, the range of the "swing" of the beam was set in the range + 40 ... + 75 degrees, while scanning in the opposite direction, the range of scan angles was -40 ... -75 degrees. When controlling a longitudinal wave, the range of "swing" of the beam was -45 ... + 45 degrees.

According to the scan results, a defect was detected in the body of the flange. The maximum size between the positions of the PAR sensor along the scan line on the control surface, at which the level of the echo signal exceeds the level of fixation, was X3-X1 = 65-10 = 55 (mm). For each position of the PAR sensor, at which the level of the echo signal exceeded the level of fixation, the angles of entry of the ultrasonic wave were determined at which the echo signal from this defect is maximum. The angles for the found extreme positions of the PAR sensor X1 and X3 were α1 = + 40 ° and α3 = -35 °, respectively. The distances along the ultrasound beam from the scanning surface to the reflection point on the defect at the maximum value of the echo signal from the defect in the position of the PAR sensor at points X1 and X3 were L1 = 25 mm, L3 = 30 mm. Then, the coordinates of the defect in the cross-section of the cast part X1 ′ and X3 ′ corresponding to points X1 and X3 were found.

The conditional extent of the defect, defined as the distance between the extreme positions of the projections of the found points in the section of the part on the scanning plane, was determined by the formula (1) and amounted to:

a = Χ3′-X1 ′ = (65 + 30 · sin (-35 °)) - (10 + 25 · sin (+ 40 °)) ≈21.7 (mm)

It was concluded that a defect with an identified conditional length was not allowed.

Claims (1)

A non-destructive testing method for molded body parts, characterized in that it comprises the steps of breaking the surface of the molded body parts into inspection areas and applying contact lubricant to them, performing ultrasonic scanning of the selected areas of the molded body parts according to the transverse-longitudinal movement pattern of the phased array sensor (HEADLIGHT): perform a sector scan with the HEADLIGHT sensor by swinging the beam while simultaneously moving the HEADLIGHT sensor in the control section first in the transverse and then in the longitudinal plane in the forward and reverse direction, and the direction of movement of the HEADLAMP sensor is carried out in the plane of the beam swing, the results of ultrasonic testing are automatically recorded together with the recording of the coordinates of the movements of the HEADLAMP sensor on the surface of the control area, by analyzing the recorded data for each sector input angle scan find the coordinates HEADLIGHTS on the surface of the inspection site, in which the amplitude of the echo exceeds the level of fixation of the amplitude of the echo, corresponding to the coordinates of the points in the cross section of the casting with the amplitude of the echo signal exceeding the level of fixation, and the conditional extent of the defect is determined by the found coordinates on the surface of the inspection site and taking into account the angles of sector scan input for each coordinate at which the maximum amplitude of the echo signal is determined as the distance between the extreme positions of the projection of certain points on the scanning plane.

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