【国外标准】 Standard Practice for Ultrasonic Examination of Turbine-Generator Steel Retaining Rings

This test method covers the procedures for the standard practice of performing ultrasonic shear and longitudinal wave examinations on turbine-generator steel retaining rings. A pulsed reflection-type ultrasonic instrument shall be used for the tests. Scanning of steel specimens may be performed by either the contact (stationary) or immersion (rotating) methods, both of which may be executed in either the axial or circumferential directions. Tests shall be performed after specimens have gone through final processing and heat treatment for properties, and the circumferential and axial faces machined flat and parallel to one another. Also prior to testing, surface examinations shall be made for surface roughness and tears, loose scales, machining or grinding particles, paint, and other foreign and extraneous matter. Suitable couplant liquids, capable of conducting ultrasonic vibrations, shall be used to couple the transducer to test surfaces.1.1 This practice covers ultrasonic examination of turbine-generator retaining rings produced in accordance with Specifications A288 and A289/A289M with an inside diameter to wall thickness ratio equal to or greater than 5:1 and with wall thicknesses from 1 in. to 4 in. [25 mm to 102 mm].1.2 Forgings may be inspected by either the contact or the immersion methods, or combinations thereof, as agreed upon between the manufacturer and the purchaser.1.3 Supplementary requirements of an optional nature are provided for use at the option of the purchaser. The supplementary requirements shall apply only when specified individually by the purchaser in the purchase order or contract.1.4 This practice is expressed in inch-pound and SI units; however, unless the purchase order or contract specifies the applicable “M” specification designation (SI units), the inch-pound units shall apply. The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the practice, the SI units are shown in brackets. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.1.5 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.1.6 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.