RU37832U1 - MEANS FOR ULTRASONIC DEFECTOSCOPY - Google Patents

Description

2004104828

  ° COIN 29/04

MEANS FOR ULTRASONIC DEFECTOSCOPY

The utility model relates to non-destructive testing of materials and can be used for ultrasonic inspection of railway rails and other long products.

A device for ultrasonic detection of defects in the head

rail, which contains two inclined ultrasonic transducers mounted symmetrically relative to the longitudinal axis on the rolling surface of the rail head and moved at a constant speed along the rail. A pair of transducers carries out alternate pulsed radiation of ultrasonic vibrations at an angle to the rolling surface in the direction of the side faces of the rail head at angles relative to the longitudinal axis of the rail. If there are displaced oval transverse cracks in the rail head, the indicated transducers receive echo signals and estimate the location (in the left or right side of the head) and the approximate orientation of the T1 wire (see US 4700754, COIN 29/04, 20.10). , 987)

The disadvantages of the known device are the low reliability and reliability of the control, due to the fact that it does not allow to detect transverse cracks occurring under the rolling surface in the central part (on the longitudinal axis of the rail head). This is because the ultrasonic rays formed by the transducers after the qf of the lower surface (lower flange) of the rail head are reflected again and continue to propagate along the lateral parts of the head almost parallel to the longitudinal axis (along the rail) without suppressing the axis of symmetry of the rail. For this reason, there are no echo signals from transverse cracks under rolling surface on the longitudinal axis of the rail. At the same time, these cracks are very dangerous, rapidly developing under the dynamic influence of the wheels of passing trains. In addition, in the known device, the gifts of inclined transducers are placed on opposite sides of the middle plane of symmetry of the rail, which

determines the significant dimensions of the system of two transducers in the transverse rail direction.

The analysis of the echo signals from the desired defects in the known device is carried out in two time zones corresponding to sounding the defect plane with a direct ultrasonic beam (from the breaker to the lower plane of the rail head) and a single-reflected beam (when the beam propagates from the lower plane to the rolling surface). Due to the features of the selected sounding scheme in the known device, echo signals from defects lying under the tread surface on the longitudinal axis of the pejibca are not analyzed, which leads to the omission of defects of a certain configuration and an additional decrease in the reliability and reliability of the control.

The device for ultrasonic detection of defects in the rail head, adopted as a prototype, contains a system of two inclined electro-acoustic transducers deployed at the same sharp angles relative to the longitudinal axis of the rail to opposite side faces of the rail head. The angles of introduction of ultrasonic vibrations into the metal of the rail and the aphids of the turn of the transducers relative to the longitudinal axis of the rail are chosen so that the axes of the ultrasonic rays falling at an oblique angle to the zones of the radius transition of the lateral and lower faces of the rail strips, reflecting from them intersect on the longitudinal axis of the rolling surface of the rail head . In this case, the projection of the trajectory of the rays inside the metal onto the skating surface forms a geometric shape of a rhombus. As the pair of transducers moves along the longitudinal axis of the rail, they emit ultrasonic vibrations and receive echoes reflected from possible defects in the rail head. The temporary position of the echo signals relative to the probing (radiated) oscillations and their amplitudes are used to judge the presence of a defect and its orientation inside the rail head. Moreover, when analyzing the signals, all signals received by the converters are taken into account.

To simplify the analysis of echo signals, the subsequent automation of the signal decryption process and the control procedure, temporary echo signals are selected in three time zones, two of which are used to select signals from cracks in the lateral parts of the rail head, and the third, additional, 2.G)

for the selection of signals from transverse cracks in 1 ntral part of the head under the rolling surface. Moreover, the signals from these defects are formed due to the re-reflection of ultrasonic vibrations Lt of the angular reflector formed by the crack plane and the rolling surface (or the plane of the subsurface horizontal crack). When these defects are detected, in contrast to the detection of cracks in the lateral parts of the head, ultrasonic vibrations are emitted by one transducer and taken by another along the beam path inside the rail head, the projection of which onto the rolling surface forms a geometric shape of a rhombus. All interfering signals, in particular from irregularities of the lower corners (zones of the radius transition), do not fall into the zones of temporary selection and do not participate in further analysis (see RU 2184960, GO IN 29/04, 07/10/02). The known device has a relatively high reliability, reliability and performance of the ultrasonic inspection of the rail head due to the effective detection of transverse cracks in the central part of the rail head, including those lying under metal detachments and horizontal cracks at a shallow depth from the rolling surface, while detecting defects in the lateral parts of the rail head.

The disadvantages of the known device include the impossibility of monitoring the entire volume of the rail, since the sounding scheme used allows reliable h reliable ultrasonic monitoring of only the rail head.

The technical result is to ensure control of the entire cross-section of the rail with the exception of feathers of the bottom of the rail.

The technical result is achieved by the fact that the means for ultrasonic inspection containing emitting and hyphium electromagnetic acoustic transducers consists of four blocks located at a distance from each other, and is arranged to place electromagnetic acoustic transducers relative to the controlled object with a gap, while in the first block the first emitting electromagnetic - acoustic transducer with an input angle of ultrasonic vibrations equal to 0 and the first receiving electric ktromagnitno - acoustic

transducer, in the second block the place is the second radiating

an electromagnetic - acoustic transducer with an input angle of ultrasonic vibrations equal to 40 ° and a second receiving electromagnetic - acoustic transducer, a third and fourth receiving electromagnetic - acoustic transducers are placed in the third block, a third and fourth emitting electromagnetic acoustic transducers with an input angle of ultrasonic vibrations are placed in the fourth block 90 ° and the fifth receiving electromagnetic - acoustic transducer. The signal receiving frequency of the fifth receiving electromagnetic - acoustic transducer can be chosen equal to the radiation frequency of the second radiating electromagnetic - acoustic transducer, which is chosen twice as high as the radiation frequency of the third radiating electromagnetic - acoustic transducer and four times higher than the radiation frequency of the fourth radiating electromagnetic - acoustic transducer.

Fig. 1 shows a diagram illustrating the location of the electromagnetic - acoustic transducers. {1st and sound zones of the controlled object.

The means for ultrasonic flaw detection will contain emitting (1. 2, 3. 4) and receiving (5, 6, 7, 8, 9) electromagnetic - acoustic transducers located in four blocks located at a distance from each other. Electromagnetically acoustic transducers with respect to the controlled object 10 are installed with a gap that is not filled with contacting magma-yum. The first block contains the first electromagnet acoustic transducer 1 with the ultrasound input of ultrasonic vibrations equal to 0 ° and the first receiving electromagnetic - acoustic transducer 5, the second block contains the second radiating electromagnetic - acoustic transducer 2 with an input angle of ultrasonic vibrations equal to 40 ° and the second receiving electromagnetic - acoustic transducer 6, in the third block the third and fourth receiving electromagnetic - acoustic transducers 7 and 8 are located, in the fourth block p zmescheny third and fourth radiating - electromagnetic acoustic transducers 3 and 4 with an input angle

oscillations 90 and the fifth receiving electromagnetic - acoustic transducer 9.

In the proposed tool for ultrasonic inspection, placed in the first block, the first emitting electromagnetic - acoustic transducer 1 and the first receiving electromagnetic - acoustic transducer 5 operate at a frequency of 1.8 MHz. Placed in the second block, the second emitting electromagnetic - acoustic transducer 2 and the second receiving electromagnetic - acoustic transducer 6 operate at a frequency of 1.0 MHz. The third and fourth emitting electromagnetic - acoustic transducers S and 4, located in the fourth block, operate at frequencies of 0.5 MHz and 0.25 MHz, respectively; the third and fourth receiving electromagnetic acoustic transducers 7 and 8, respectively, located in the third block, operate at the same frequencies. receiving electromagnetic-acoustic transducer 9, located in the fourth block, operates at a frequency of radiation (1 MHz) of the second emitting electromagnetic-acoustic transducer 2. The selected ratio CAS | Goth allows you to create the desired radiation pattern of the emitting and receiving electromagnetic - acoustic transducers and significantly reduce their impact on the operation of the radiation and reception channels formed by other electromagnetic acoustic transducers. However, in the proposed tool for ultrasonic flaw detection, all transducers can operate at the same excitation frequency. The choice of the nominal input angles of ultrasonic vibrations equal to 0 °, 40, and 90 ° made it possible to realize the sounding zone (see Fig. 1), at which the entire rail volume is controlled, i.e. the dead zone of control in this case is actually zero. The types of radiated waves in the proposed tool for ultrasonic inspection can be

transverse, Rayleigh, different polarization.

Claims (2)

1. Means for ultrasonic inspection, containing emitting and receiving electromagnetic-acoustic transducers, characterized in that it consists of four blocks located at a distance from each other, and is configured to place electromagnetic-acoustic transducers relative to the controlled object with a gap, while the first block contains the first emitting electromagnetic-acoustic transducer with an input angle of ultrasonic vibrations equal to 0 ° and the first receiving electromagnetic an acoustic transducer, in the second block there is a second emitting electromagnetic-acoustic transducer with an input angle of ultrasonic vibrations equal to 40 ° and a second receiving electromagnetic-acoustic transducer, in the third block there are a third and fourth receiving electromagnetic-acoustic transducers, in the fourth block the third and fourth emitting electromagnetic-acoustic transducers with a 90 ° angle of oscillation and the fifth receiving electromagnetic-acoustic transducer. 2. The means for ultrasonic inspection according to claim 1, characterized in that the frequency of reception of the signal of the fifth receiving electromagnetic-acoustic transducer corresponds to the radiation frequency of the second emitting electromagnetic-acoustic transducer, which is two times higher than the radiation frequency of the third radiating electromagnetic-acoustic transducer and four times the radiation frequency of the fourth electromagnetic-acoustic transducer.