ASTM E1255-23: Standard Practice for Radioscopy

Standards Editor: Hossein Taheri, PhD: Georgia Southern University, Statesboro, GA; [email protected]

Radioscopy is a nondestructive testing (NDT) technique used to inspect the internal structure of objects or materials using X-rays in real-time. Also known as real-time X-ray inspection, radioscopy involves the use of X-ray imaging equipment to produce dynamic, live images of the interior of an object as it is being examined. This technique is commonly used in various industries, including aerospace, automotive, manufacturing, and electronics, to detect defects, flaws, or irregularities in components such as welds, castings, and assemblies. Radioscopy is particularly useful for examining complex or intricate structures where traditional inspection methods may be impractical or insufficient.

In the early 20th century, industrial radiography emerged as a method for inspecting welds and detecting defects in metal components. However, the conventional radiographic techniques of that time provided static images, limiting their effectiveness in inspecting moving or dynamic objects. The development of radioscopy can be attributed to the need for real-time imaging of industrial components, particularly during manufacturing and assembly processes. Radioscopic techniques evolved to allow continuous X-ray imaging of objects in motion, enabling inspectors to monitor and detect defects in real-time. Advancements in X-ray technology, imaging systems, and computer processing capabilities further refined radioscopy over the decades. Modern radioscopy systems utilize digital imaging technology, high-speed X-ray detectors, and advanced image-processing algorithms to provide real-time, high-resolution images of internal structures.

The most recent version of ASTM E1255 (ASTM E1255-23), released in the Annual Book of ASTM Standards, Vol. 03.03, was developed by ASTM subcommittee E07.01. This standard defines fundamental parameters for implementing and regulating the radioscopic examination technique. It is designed to be referenced in engineering drawings, specifications, or contracts for clarity and consistency. The table provides an overview of examinations for major components outlined in ASTM E1255-23, along with corresponding complementary ASTM practices for each component.

This standard outlines the application details for radioscopic examination using penetrating radiation, employing analog components like electro-optic devices (e.g., X-ray image intensifiers or analog cameras) or digital detector arrays (DDAs) in dynamic-mode radioscopy. Radioscopy involves real-time tracking of motion or optimization of radiographic parameters, with frame rates ranging from 25 to 30 frames per second for dynamic mode, near real-time (a few frames per second), or high speed (hundreds to thousands of frames per second). Additionally, static-mode radioscopy is discussed, where there is no motion of the object during exposure, serving as a filmless recording medium. It should be noted that static mode radioscopy using DDAs is not covered here; Practice E2698 should be referenced for such applications.

This practice also extends to linear detector array applications, where relative perpendicular motion of either the detector or the component under examination builds an image line by line. Furthermore, it can be applied to “flying spot” scenarios, where a pencil beam of X-rays scans over an area to construct an image point by point.

While establishing minimum requirements for radioscopic examination of metallic and nonmetallic materials using X-ray or gamma radiation, this practice does not intend to limit or restrict applications but rather aims to address general technology applications and promote its use. For additional information and guidance, references to Guides E94 and E1000, as well as Terminology E1316, are provided.

To read the original article, please view it in the April 2024 issue of Materials Evaluation here.