[en] The report describes investigations and developments concerning ultrasonic techniques for the detection of cracklike and corrosive defects in vessels and pipes. Horizontally polarized shear (SH-)waves are used, which have advantageous features for these inspection tasks. Besides the complete corner reflection in the whole angle of incidence range and the grazing incidence along the near probe surface their propagation isn't influenced by liquids in contact with the surfaces. In thin walled components like plates and pipes (wall thickness ≤ 15 mm) these waves propagate as guided waves over large distances (up to 1 m) and are well suited for the inspection of large areas of these very commonly used components in the chemical industry. Free of couplant transmission and reception of these waves are realized by Electro-Magnetic Ultrasonic (EMUS)-transducers. The EMUS-technique is capable to perform inspections up to 300deg C without any cooling means by appropriate construction of the probes, so that the most components can be inspected at their temperatures of operation. Investigations have been performed concerning the detection of corrosive defects (wastage, pitting) in plates and tubes by guided SH-waves and cracklike defects - single cracks and crack-fields - by oblique incidence of bulk SH-waves. Laboratory measurements as well as trials in the field on real components have been carried out. (orig.)

[en] A sufficient amplification reserve can be reached even for free us-waves for many testing problems. Hereby there is a chance to introduce the advantages of the absence of coupling-media into practice. The results in pipe-waves are assured to a for extent in the laboratory stadium for the detection of cross-cut faults and free waves for perpendicular and angular incoupling of transversal waves. (DG)

[en] The measurement of flow speeds and levels of filling in pipelines and vessels requires a process of measurement to which the medium inside the pipe or the vessel is accessible. This problem can be solved by ultrasonics: Ultrasonics can 'penetrate' solids and liquids and therefore give access to the medium from outside. In this article, a survey is given in the first part on various techniques for measuring the speed of flow of liquids. The physical principles are introduced and the boundary conditions are discussed. In the second part, a practical example of measuring the level of filling in vessels and pipelines from outside at temperatures up to 300 C is given. (orig./HM)

[en] The EMUS (electro-magnetic ultrasonic) technique expands conventional technique by its specific strengths, i.e.: The freedom from a means of coupling, the high effectiveness and selectivity in converting transverse waves of both polarisations and the conversion of guided waves with polarisation in and at right angles to the plane of incidence. The use of EMUS angle test heads for testing pipelines is described using the example of repeated tests of Austenitic and mixed welded joints with free horizontal polarized transverse waves (SH waves) and the testing of whole areas for corrosion damage on sheets and pipe walls by guided SH waves. (orig./HP)

No abstract available

[en] An overview is given about modern ultrasonic testing methods with quantitative interpretation and imaging capability based upon synthetic aperture methods which have been developed during the last decade. The basic principle, physical limitations, equipment and industrial applications are discussed for ALOK, PHASED ARRAY, HOLOSAFT and EMUS. (orig.)

[en] For developing ultrasonic applications in the nuclear field, EMUS test heads were designed for temperatures up to 300deg C. It was shown that an EMUS hot test head for this temperature range is simple to produce. Regarding the temperature dependence of the sound conversion parameter, no negative effects were observed. The test sensitivities determined in cold experiments can therefore also be expected in hot applications. (orig.)

[en] Applying HF transformers in the radio-frequency unit of EMUS angle probes the distance between material surface and HF coil was considerably increased so that the coil is protected against mechanical damage. In addition, a clear decrease in the probe dimensions was achieved. This design development permits a number of applications which efficiently make use of these improvements: filling level control in the reactor pressure vessel of heavy-water reactors, early detection of creep damage in high temperature components of fossil fueled power stations. (orig./MM)

[en] Bimetallic transition welds include in most cases besides the austenitic weldment an austenitic buttering. Their inspection by ultrasound is strongly complicated by a high degree of elastic anisotropy. The elastic anisotropy results in phase and group velocities of the elastic wave-modes, which are functions of the propagation direction inside the weld metal and which cause skewing of the sound beams. The coarse grain structure leads to enhanced scattering. Furthermore, there exists a mismatch of the acoustical impedances between the weld metal and the base metal, which depends on the angle of incidence at the interface base metal/weld metal and weld metal/buttering. Due to these facts up to now using standard UT-techniques only the HAZ's are inspected from both sides. In many cases dissimilar metal welds are only accessible from one side. Therefore, US-techniques are necessary which are capable to inspect the whole weld even if there is only access from one side. By improvement of the technology of the EMUS-probes and of the EMUS-instrumentation for the US-transduction of SH-waves a reliable technique for the ISI of dissimilar metal welds and also of austenitic welds is available. The contribution will shortly introduce into the physical basis of the SH-wave technique and present the results of test specimen measurements. The main part of the paper will report about the experiences and the results of field applications in different nuclear power plants

No abstract available