Radiographic Test (X-Ray and Gamma)
X-ray sources, Gamma ray sources, gamma ray camera protectors, film holders, lead screens, film processing equipment, film viewers, exposure facilities, radiation monitoring equipment.
Welds which have voluminous discontinuities such as porosity, incomplete joint penetration, corrosion, etc. Lamellar type discontinuities such as cracks and incomplete fusion can be detected with a lesser degree of reliability. May also be used in certain applications to evaluate dimensional requirements such as fit-up, root conditions, and wall thickness.
Adjustable energy levels. Generally produces higher quality radiographs than gamma sources. Surface and subsurface inspection capability. Radiographic images aid in characterizing discontinuities. Provides a permanent record for future review.
Generally not restricted by type of material or grain structure. Surface and subsurface inspection capability. Radiographic images aid in characterizing discontinuities. Provides a permanent record for future review.
Planar discontinuities must be favourably aligned with radiation beam to be reliably detected. Radiation poses a potential hazard to personnel. Cost of radiographic equipment, facilities, safety programs and related licensing is relatively high. A relatively long time between exposure process and availability of results. Accessibility to both sides of the weld required. High initial cost of X-ray equipment. Not generally considered portable.
Source: American Welding Society Inc., The McGraw-Hill Companies Inc.