【国外标准】 Standard Practice for Examination of Seamless, Gas-Filled, Steel Pressure Vessels Using Angle Beam Ultrasonics

5.1 The purpose of this practice is to provide a procedure for locating, detecting and estimating the relevance of longitudinally oriented crack-like discontinuities which have been previously indicated by AE examination.5.2 This practice may be used for a pressure vessel that is situated in such a way as to limit access to the vessel's wall. Typical examples include tube trailers and gas tube railroad cars. Since the pressure vessels are stacked horizontally in a frame, with limited space between them, the circumferential location of a discontinuity may be a distance away from the search unit (several skip distances).5.3 This practice has been shown to be effective for cylinders between 9 in. (229 mm) and 24 in. (610 mm) in diameter and wall thicknesses between 1/4 in. (6.4 mm) to 1 in. (26 mm) with discontinuities that are oriented longitudinally in pressure vessel sidewall.5.4 To reliably detect discontinuities by the procedure in this practice, a significant part of the reflecting surface must be transverse to the beam direction.5.5 Evaluation of possible discontinuity in the end faces indicated by AE is not covered by this practice.1.1 This practice describes a contact angle-beam shear wave ultrasonic technique to detect and locate the circumferential position of longitudinally oriented discontinuities and to compare the amplitude of the indication from such discontinuities to that of a specified reference notch. This practice does not address examination of the vessel ends. The basic principles of contact angle-beam examination can be found in Practice E587. Application to pipe and tubing, including the use of notches for standardization, is described in Practice E213.1.2 This practice is appropriate for the ultrasonic examination of cylindrical sections of gas-filled, seamless, steel pressure vessels such as those used for the storage and transportation of pressurized gasses. It is applicable to both isolated vessels and those in assemblies.1.3 The practice is intended to be used following an Acoustic Emission (AE) examination of stacked seamless gaseous pressure vessels (with limited surface scanning area) described in Test Method E1419.1.4 This practice does not establish acceptance criteria. These are determined by the reference notch dimensions, which must be specified by the using parties.NOTE 1: Background information relating to the technical requirements of this practice can be found in the references sited in Test Method E1419, Appendix X1.1.5 Dimensional values stated in inch-pound units are regarded as standard; SI equivalents, in parentheses may be approximate.1.6 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.1.7 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.