No abstract available

[en] Code Case N-458, Magnetic Particle Examination of Coated Materials, and Code Case N-485, Eddy Current Examination of Coated Ferritic Surfaces as an Alternative to Surface Examination, were approved in 1990 for Section 11, Division 1 of the ASME Boiler and Pressure Vessel Code. Activity that led to these cases, research results on which the requirements in these cases were based, and future ASME Code plans related to surface examination through coatings are discussed in this paper. 2 refs

[en] This paper discussed the principles and techniques of Eddy current testing as the best non-destructive testing methods of testing in heat exchangers. (ELC). 6 figs

[en] Nondestructive testing (NDT) is the use of physical and chemical methods for evaluating material integrity without impairing its intended usefulness or continuing service. Nondestructive tests are used by manufaturer's for the following reasons: 1) to ensure product reliability; 2) to prevent accidents and save human lives; 3) to aid in better product design; 4) to control manufacturing processes; and 5) to maintain a uniform quality level. Nondestructive testing is used extensively on power plants, oil and chemical refineries, offshore oil rigs and pipeline (NDT can even be conducted underwater), welds on tanks, boilers, pressure vessels and heat exchengers. NDT is now being used for testing concrete and composite materials. Because of the criticality of its application, NDT should be performed and the results evaluated by qualified personnel. There are five basic nondestructive examination methods: 1) liquid penetrant testing - method used for detecting surface flaws in materials. This method can be used for metallic and nonmetallic materials, portable and relatively inexpensive. 2) magnetic particle testing - method used to detect surface and subsurface flaws in ferromagnetic materials; 3) radiographic testing - method used to detect internal flaws and significant variation in material composition and thickness; 4) ultrasonic testing - method used to detect internal and external flaws in materials. This method uses ultrasonics to measure thickness of a material or to examine the internal structure for discontinuities. 5) eddy current testing - method used to detect surface and subsurface flaws in conductive materials. Not one nondestructive examination method can find all discontinuities in all of the materials capable of being tested. The most important consideration is for the specifier of the test to be familiar with the test method and its applicability to the type and geometry of the material and the flaws to be detected

No abstract available

[en] Remote Field Eddy Current (RFEC) is now an established method for the inspection of carbon steel feedwater heater tubes. Recently, improvements in equipment design and advanced signal processing methods have increased the usefulness of this method. Descriptions of some of the advances and examples of their application are given. 2 figs., 1 tab

[en] In eddy current testing the excitation of the magnetic fields is commonly pratized by sinusoidal currents, but there is also the possibility to applicate pulsed currents. Experimental and theoretical foundations of the pulsed eddy current method has been mainly developed in USA. The principle of this method will be explained. The penetration of a magnetic field is described as diffusion process. In the case of a plan wave the shapes of the magnetic fields and the eddy current densities are shown. By examples the efficiency and possibilities of applications are discussed. (orig.)

No abstract available

[en] Mapping provides an eddy-current image of the examined surfaces which is independent from the data acquisition method. Optimization of viewing angle, contrast and perspective plotting contributes to enhancement of image quality. Image interpretation is facilitated by signal pre-processing in the form of filtering, removal of spurious repetitive patterms, or non-linear amplification

[en] The paper concerns the role of the Windscale Engineering Development Group, United Kingdom, in an international exercise on eddy current testing of fuel cladding. The exercise was organised by the reactor project at Halden in Norway, which is run under the auspices of the Organisation for Economic Cooperation and Development. Thirteen laboratories in eight countries were given a remit to use eddy current testing, a standard non-destructive testing method, to locate and characterise specific defects. The eddy current test is described, along with the Windscale development work on transducers and signal analysis carried out in preparation for the test. The test programme is outlined; Windscale Laboratory successfully detected and located the defects. (U.K.)