SU945779A1 - Flaw detector acoustic section adjustment method - Google Patents

Description

(54) ACOUSTIC TRACT SETTING METHOD

DEFECTOSCOPE

The invention relates to a reference measurement technique and can be used for flaw detection of ferromagnetic products by a contactless ultrasonic method. The known method of excitation of surface waves is that a constant and alternating magnetic fields are created in the excitation zone, directed at right angles to each other. Cl. The disadvantage of this method 5 is the impossibility of excitation of surface waves with horizontal polarization. The closest in technical essence to the invention is the method of locating the acoustic path of a flaw detector with electromagnetic-acoustic control with surface waves of products made of magnetic materials, which implies that in the excitation and reception areas the product is affected by constant and alternating magnetic fields the signal from the surface waves that passed through the controlled product and the amplitude of this stringer judged the tuning of the acoustic path 2. A known method allows you to adjust the defectos op control surface waves on a horizontal floor Fusarium by varying the angle between AC and DC fields, but its drawback is the inability to adjust for maximum sensitivity, since the efficiency of excitation wave yoverhnostnoy It appears low. The purpose of the invention is to provide adjustment to the maximum sensitivity by increasing the efficiency of the excitation & ki waves with horizontal polarization. This goal is achieved by the fact that the product is affected by an additional magnetic field with an induction vector lying in the plane of the surface of the product, and the direction of this vector is changed to

obtaining the maximum received signal.

The drawing shows a diagram of the real-time method.

The scheme consists of exciting

electro-acoustic transducer 1, receiving transducer 2 located in a controlled model 3. Transmitter 1. is connected to the output of the flaw detector generator 4, and transducer 2 to the input of the flaw detector's receiving amplifier 5.

 The dryness of the process lies in the following.

The generator 4 generates a pulse in the waveguide transducer 1, the product & 3 is impacted in the excitation and reception zones with a constant field Hg, and the surface waves transmitted by the transducer 2 are impacted by transducer 2.

Additionally, impact 3 is applied in the war propagation zone lying between transducer mc 1 and 2, a constant field FL, whose vnduksh vector lies in the planar surface of product 3. The direction of the vector should be an angle between 0 and 9O. The presence of additional magnets in the surface layer creates a static magnetic-stress-strain deformat, which changes the elastic material of the material in this layer. As a result, conditions are obtained in which the ms ket is effectively excited and cleared the surface of the horizon with the horizontal polarization of the c.j & taeni vector (Lwa wave). Men - Vpredladae vector Hj,, found his position when s-ygnal removed from

the receiver 2, and hence the amplitude of the elastic wave is maximum. In this case, the flaw detector will have a maximum sensitivity to the detected defects.

The invention allows an increase in the excitation efficiency by providing a flaw detector with a maximum sensitivity.

Claims (1)

1. Defectoscopy, 1974, Ms 2, p. 45-54. 2i. Proceedings of the IX All-Union acoustic konferevvvv. M., 1977, В + П1У в- 5, p. (prototype).