Specialized converters are used when the application of ordinary converters is difficult, impossible or inefficient. For example, separated-combined oblique piezoelectric converters (chordwise converters, “Tandem”, “Duet”) are used to examine butt joints of thin-wall tubes, welded tee-joints etc. Specialized piezoelectric converters have given a good account of themselves in various branches of industry. We have favorable reports from different enterprises.
RSM – 5F ultrasonic chordwise focusing converters
RSM – 5F separated-combined oblique focusing converters are intended for quality control of butt joints of small-diameter pipelines (16–51 mm) with wall thickness 2.0–6.0 mm. The converter operating frequency is 5 MHz. Ultrasonic beam focusing allows detecting volumetric defects 0.1 mm in diameter and above. Chordwise configuration is especially sensitive to flute cracks and flat flaws (cracks, incomplete root penetration). Chordwise scanning configuration provides high noise resistance against beads and sags in welded joints. There is no transverse scanning during flaw detection. The converters may be used with ultrasonic flaw detectors produced in Russia and abroad. RSM-5F method of use is approved by Gosgortechnadzor of Russia. There are favorable reports from enterprises which use these piezoelectric converters.
Technical characteristics
| Designation | Tested diameters, mm | Tested thickness, mm | Case dimensions (L x W x H), mm |
| RSM-5Ф-Ø16 | 16 | 1,5…6,0 | 50х17х16 |
| RSM-5Ф-Ø18 | 18 | Value:
| |
| RSM-5Ф-Ø21 | 21 | ||
| RSM-5Ф-Ø25 | 25 | ||
| RSM-5Ф-Ø28 | 28 | ||
| RSM-5Ф-Ø32 | 32 | ||
| RSM-5Ф-Ø36 | 36 | ||
| RSM-5Ф-Ø38 | 38 | ||
| RSM-5Ф-Ø42 | 42 | ||
| RSM-5Ф-Ø45 | 45 | ||
| RSM-5Ф-Ø48 | 48 | ||
| RSM-5Ф-Ø51 | 51 | ||
*manufacture of other possible probes for ultrasonic pipe diameter ∅ 10 … 325mm, thickness 1.5 … 9 mm
“Duet” type ultrasonic converters (series P122 “Duet”)
“Duet” type ultrasonic converters (series P122 “Duet”) Separated-combined oblique converters of the “Duet” type are intended for ultrasonic examination of thin-wall welds of pipelines from Ø57 mm and above and wall thickness 3.0–6.0 mm. The operating frequency of the converters is 5 MHz. The introduction angle is 70 degrees. The application of separate switching circuits allows the avoidance of reverberation noise and reduces the dead area to 0–0.5 mm. The “symmetrical duet” configuration is highly sensitive to root defects because the oscillator is turned with respect to the receiver and the beam is focused in the operating area. A standard adjustment technique is used (by “dents” and “segments”). The working face of the converters is provided with an antiwear coating to increase its surface life. The converters may be used with ultrasonic flaw detectors produced in Russia and abroad.
Technical characteristics
| Designation | Tested diameters, mm | Tested thickness, mm | Case dimensions (L x W x H), mm |
| P122-5,0-70 “Duet” | 57…63 | 2,5…6,0 | 24х18х22 |
| 75…89 |
| ||
| 102…114 | |||
| 127…168 | |||
| 194…219 | |||
| плоский, более 219 | |||
SP5-75KUS (“duplex tandem”) ultrasonic transducers
SP5-75KUS (universal) separated-combined oblique ultrasonic converters are intended for quality control of butt joints of pipes, vessels and steel structures with wall thickness of 4–13 mm. The converter is of a “duplex tandem” design. The operating frequency of the converters is 5 MHz, and the introduction angle is 73–75 degrees. A duplex converter configuration provides high noise resistance against sags and increased sensitivity towards planar defects (cracks, incomplete penetration). Converters of this type allow checking of the acoustic contact level and sensitivity, since they form an additional acoustic contact echo-pulse which is visible on the flaw detector display, so it may be used on painted surfaces
During examination scanning is performed only along a welded joint. The working face of the converters is provided with an antiwear coating which increases their service life by 5–10 times. SP5 – 75KUS converters may be used to examine items from 57 mm in diameter to flat surfaces. The method of use is approved by Rostechnadzor of Russia. There are favorable reports from end users, a diploma of an international exhibition and a patent.
Diagram of the converter SP5-75KUS
Technical characteristics
| Designation | Tested diameters, mm | Tested thickness, mm | Case dimensions (L x W x H), mm |
| SP5 – 75KUS | 57 to surface and more | 2,5…12 | 44х20х35 |
| SP5 – 75KUS MU | 57 to surface and more | 2,5…12 | 44х28х35 |
Transducers for ultrasonic testing of welded joints of polyethylene pipes
“Duet” and “Tandem” specialized ultrasonic converters, type P122-1,8, are used for ultrasonic examination of contact-welded joints of polyethylene pipelines. During the relatively short period of their practical application the converters have given a good account of themselves in field and factory applications. Separate switching circuits and big introduction angles allow the reliable detection of vertically-oriented planar defects within the cross-section of a welded seam, at a high signal-noise ratio. Adjustment is performed by flat-bottom apertures. The method of use is approved by Gosgortechnadzor of Russia. Converters can be designed to match other standard sizes of polyethylene pipes SDR11; SDR17.6; SDR7.4, made of PE-63 and PE-80 polyethylene, and others.