Sensitivity of the Electromagnetic Acoustical Technique for Testing Railway Rails by the Mirror-Shadow Method

State-of-the-art capabilities of EMA flaw detection

“…However, precisely this method has been used in recent studies devoted to the EMA transformation [1, 4-29, 40, 41]. It can be used in solving problems on the detection of continuity violations [5,13,42], thickness measurements [18,19,21,43,44], metal-grain measurements [1], etc., at frequencies of f = 0.1-30 MHz. The EMA technique can also be used at frequencies up to 100 MHz [45].…”

“…The further service of this facility yields an economic effect of ~105 million rubles a year owing to an increase in both the quality of products and the inspection rate and exclusion of the procedure of conditioning the articles' surfaces, which costs approximately 550 rubles/t. In addition, the introduction of overall inspection leads to a sharp increase in the processing discipline.FEASIBILITIES OF THE EMA TECHNIQUE DURING NONDESTRUCTIVE TESTING As in the case of contact acoustics, the flaw detection with the use of the EMA technique predominantly utilizes two inspection techniques: pulsed and resonant [1,5,20]. The pulsed method is implemented by using mainly the same electronic units [32] as those in conventional ultrasonic instruments, in which sound is excited and received by piezoelectric transducers [33].…”

“…FEASIBILITIES OF THE EMA TECHNIQUE DURING NONDESTRUCTIVE TESTING As in the case of contact acoustics, the flaw detection with the use of the EMA technique predominantly utilizes two inspection techniques: pulsed and resonant [1,5,20]. The pulsed method is implemented by using mainly the same electronic units [32] as those in conventional ultrasonic instruments, in which sound is excited and received by piezoelectric transducers [33].…”

“…It should be noted that all known inspection methods are based on the EMA technique: the through-transmission [1] and mirror through-transmission [5] methods, the echo method [8], the echo and through-transmission method [58], the time-of-flight diffraction method [11], etc. The most complex problems arise when the echo method of inspection by the EMA technique is used.…”

“…Since 1983, all rails produced at the OAO Kuznetsk Iron and Steel Works, OAO Nizhni Tagil Iron and Steel Works, and OAO Azovstal' Mariupol Iron and Steel Works have been subjected to nondestructive testing by the mirror through-transmission method in the cross section restricted to the rail-neck thickness [4,5,27] and in the railhead cross section (OAO Kuznetsk Iron and Steel Works) [20,96]. Attempts to test ferromagnetic rods [55]; tubes [12,28,56,57]; separators of bearings [25]; rolled sheets [58]; billets of round cross sections [26]; and other articles [1] produced from steel [4,9,26,28,39,42,57], cast iron [9], aluminum [9,36], copper-and titanium-based alloys [1,9,59], composite materials [60], etc., have been undertaken.…”