1.1 本规程涵盖了涡流阵列（ECA）或涡流传感器在碳钢焊缝无损检测中的使用。它包括检测此类接头中的表面断裂裂纹并确定其大小，以适应传感器和接头之间厚度高达5 mm的非磁性和非导电涂层。本规程涵盖了焊缝不同位置（例如热影响区、焊趾区域和焊帽）的各种裂纹缺陷，如疲劳裂纹和其他类型的平面不连续性。它涵盖了此类表面断裂不连续的长度和深度尺寸。本规程可用于平焊和非平焊焊缝。对于特定的铁合金或特定的焊接零件，用户可能需要更具体的程序。 1.2 单位- 以国际单位制表示的数值应视为标准值。本标准不包括其他计量单位。 1.3 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.4 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 4.1 用于碳钢焊缝裂纹检测和尺寸确定的涡流阵列- 涡流传感器阵列允许快速检查碳钢焊缝是否存在最靠近传感器阵列表面的表面断裂裂纹。如指南中所述 E2884 ，这些传感器阵列可以为阵列的每个元素具有多个驱动感测对，或具有多个单独感测元素的大型单驱动绕组结构。然而，并非所有ECA探头设计都允许在有效范围内（例如，几毫米）对此类不连续性进行精确的深度尺寸确定。为了实现适当的裂纹深度尺寸，系统应表现出某些特征，例如: (1) 提升信号，允许在检查的相关值范围内监测提升， (2) 提升信号和缺陷信号之间的适当分离（这取决于所使用的仪器，可以视为阻抗平面显示器中的相位分离）， (3) 利用提升值确定裂纹深度的能力， (4) 考虑材料特性变化的能力，以确定焊缝沿线和整个焊缝的裂纹深度，以及 (5) 阵列传感元件的均匀灵敏度，以提供有效的单通检查，这在使用阵列传感器时是预期的。 4.2 阵列传感器和单传感元件传感器- 根据焊缝几何形状，可以使用传感器阵列或带有单个传感元件的传感器。传感器阵列通常提供了更好的焊缝特性空间表示，并提高了不连续检测的概率。阵列的大小以及阵列内单个传感元件的大小和数量取决于焊缝几何形状和其他因素，例如目标不连续性。当使用单个传感元件传感器时，其产生的信号应表现出下列特征: 4.1 并且从扫描线到目标不连续性的最大距离，在指定的检测概率下可能检测到，通常为5 毫米。 如果进行光栅扫描，则可以使用单元件传感器获得焊接区域的成像。 4.3 适形传感器- 检查未磨平的焊缝通常需要一个适形阵列传感器，至少沿一个轴。当阵列横向定位于焊缝并沿焊缝长度扫描时，适形传感器是允许单个传感元件遵循焊帽轮廓并在检测期间在感兴趣区域上提供均匀响应的关键。 4.4 裂纹深度范围- 阵列传感器能够提供精确测量的裂纹深度尺寸范围取决于传感器几何形状，例如单个传感元件的尺寸和配置。例如，较大的传感元件可以提供确定较深裂纹尺寸的能力，但对浅裂纹的检测能力有限。适当的阵列传感器选择和工作频率对于确保给定应用的适当性能至关重要。 典型工作频率范围为10 kHz和500 千赫。 4.5 涂层厚度范围- 阵列传感器能够可靠检测和确定裂纹尺寸的涂层厚度范围取决于单个传感元件尺寸和整体探头几何形状以及其他参数。对于任何涂层焊缝检查，验证涂层厚度是否在探头规范范围内对于确保足够的结果至关重要。 4.6 裂纹长度范围- 阵列传感器性能最佳的裂纹长度范围取决于单个传感元件的尺寸和对数据执行的任何数据处理。单个传感元件的尺寸主要影响可检测的最小裂纹长度，而数据处理（例如高通滤波器）可能对最大可测量裂纹长度产生关键影响。 4.7 灵敏度均匀性- 为了提供高检测概率并允许精确的长度和深度大小，阵列感测元件的灵敏度必须均匀。 阵列传感器的灵敏度变化不得大于15 %. 阵列的灵敏度取决于单个传感元件的尺寸和配置，并应考虑确定整体阵列精度。可能需要重叠的单个传感元件来实现足够的灵敏度均匀性（例如，这可以通过单个传感元件的多个交错行或以与扫描方向不垂直的角度定向的线性阵列来实现）。 4.8 尺寸和精度- 根据材料特性和焊缝表面状况，系统有一个最佳测量性能范围。仪器和传感器阵列探头、空气基准测量和已知材料基准测量以及操作程序通常允许深度尺寸在±30范围内 % 真正的深度。当系统在其最佳范围外运行时，深度定径精度会降低。

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. ====== 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 the maximum distance from the scan line to a target discontinuity, potentially detectable at a specified probability of detection, is typically 5 mm. Imaging of the weld region can be obtained with a single element sensor if raster scanning is performed. 4.3 Conformable Sensors— Examining welds that are not ground flush typically requires a conformable array sensor, minimally along one axis. A conformable sensor is key to allowing the individual sensing elements to follow the profile of the weld cap, and to provide a uniform response over the region of interest during the examination when the array is oriented transverse to the weld and scanned along the length of the weld. 4.4 Crack Depth Range— The crack depth sizing range over which the array sensor can provide accurate measurement depends on the sensor geometry, such as individual sensing element size and configuration. For example, larger sensing elements may provide the ability to size deeper cracks, but offer limited detection capability for shallow cracks. Appropriate array sensor selection and operating frequency is critical to ensure adequate performance for a given application. Typical operating frequencies range between 10 kHz and 500 kHz. 4.5 Coating Thickness Range— The coating thickness range over which the array sensor can reliably detect and size cracks depends on the individual sensing element size and overall probe geometry, among other parameters. For any coated weld examination, a verification that the coating thickness is within the probe specification range is critical to ensure adequate results. 4.6 Crack Length Range— The crack length range over which the array sensor performs best depends on the individual sensing element size and on any data processing performed on the data. The size of the individual sensing element mainly affects the minimum crack length detectable, while data processing (a high pass filter, for example) may have a critical impact on the maximum measurable crack length. 4.7 Sensitivity Uniformity— In order to provide a high probability of detection and allow accurate length and depth sizing, it is critical that the sensitivity across the sense elements of the array be uniform. The array sensor shall exhibit variations in sensitivity no greater than 15 %. The sensitivity across the array depends on the size and configuration of single sensing elements and shall be considered to determine the overall array accuracy. Overlapping individual sensing elements may be required to achieve the adequate level of sensitivity uniformity (for example, this can be achieved with multiple staggered rows of single sensing elements or with a linear array oriented at a non-perpendicular angle to the scan direction). 4.8 Sizing and Accuracy— Depending on the material properties and weld surface condition, there is an optimal measurement performance range for the system. The instrument and sensor array probe, the air reference measurement and known material reference measurement, along with the operation procedure typically allow depth sizing within ±30 % of its true depth. Depth sizing accuracy is reduced when the system is operated outside its optimal range.