1.1 本规程涵盖根据规范生产的涡轮发电机扣环的超声波检查 288 和 289米/289米 内径与壁厚之比等于或大于5:1，壁厚为1 英寸至4英寸[25 毫米至102毫米]。 1.2 锻件可通过制造商和买方商定的接触法或浸入法或其组合进行检查。 1.3 提供了可选性质的补充要求，供买方选择使用。只有当买方在采购订单或合同中单独规定时，补充要求才适用。 1.4 这种做法以英寸磅和国际单位制表示；但是，除非采购订单或合同规定了适用的“M”规格名称（国际单位制），否则应采用英寸磅单位。以国际单位制或英寸磅单位表示的数值应单独视为标准。在实践中，国际单位制单位显示在括号中。每个系统中规定的值可能不是完全相等的；因此，每个系统应独立使用。将两个系统的值结合起来可能会导致不符合标准。 1.5 本标准并不旨在解决与其使用相关的所有安全问题（如有）。 本标准的使用者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。 1.6 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。

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.