ASTM E3052-21 PDF

SIGNIFICANCE AND USE 4.1 Eddy Current Arrays for Crack Detection and Sizing in Carbon Steel Welds—Eddy current sensor arrays permit rapid examination of carbon steel welds for surface-breaking cracks located on the surface closest to the sensor array. As described in Guide E2884, these sensor arrays can have multiple drive-sense pairs for each element of the array or a large single drive winding construct with multiple individual sense elements. However, not all ECA probe designs allow for accurate depth sizing of such discontinuities over a significant range (several millimeters, for example). To achieve proper crack depth sizing, the system shall exhibit certain characteristics, such as: (1) a lift-off signal that allows monitoring the lift-off over the range of values of interest for the examination, (2) suitable separation between the lift-off signal and the defect signal (this depends upon the instrument used and can be viewed as a phase separation in an impedance plane display), (3) the capability to make use of the lift-off values for crack depth determination, (4) the capability to take into account material properties variations for crack depth determination along and across the weld, and (5) a uniform sensitivity for the sensing elements of the array in order to provide an effective single-pass examination, which is expected when using an array sensor. 4.2 Array Sensors and Single Sensing Element Sensors—Depending on the weld geometry, it may be possible to use either a sensor array or a sensor with a single sensing element. The sensor array generally provides a better spatial representation of the weld properties and an improved probability of detection for discontinuities. The size of the array, as well as the size and number of individual sensing elements within the array depend on the weld geometry and other factors such as target discontinuities. When a single-sensing element sensor is used, it shall produce signals that exhibit the characteristics listed in 4.1 and th... SCOPE 1.1 This practice covers the use of an eddy current array (ECA) or an eddy current sensor for nondestructive examination of carbon steel welds. It includes the detection and sizing of surface-breaking cracks in such joints, accommodating for nonmagnetic and nonconductive coating up to 5 mm thick between the sensor and the joint. The practice covers a variety of cracking defects, such as fatigue cracks and other types of planar discontinuities, at various locations in the weld (heat-affected zone, toe area, and weld cap, for example). It covers the length and depth sizing of such surface-breaking discontinuities. This practice can be used for flush-ground and not flush-ground welds. For specific ferrous alloys or specific welded parts, the user may need a more specific procedure. 1.2 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.