Значение и использование
This guide is intended to illustrate the fabrication of ultrasonic reference blocks that are representative of the production material to be examined. Care in material selection and fabrication can result in the manufacture of reference blocks that are ultrasonically similar to the production material thus eliminating the reference block as an examination variable.
1.1 This guide covers general procedures for thematerial selection and fabrication of reference blocks made ofmetal or metal alloys and intended to be used for the examinationof the same or similar production materials by pulsed longitudinalultrasonic waves applied perpendicular to the beam entry surface.Primary emphasis is on solid materials but some of the techniquesdescribed may be used for midwall examination of pipes and tubes ofheavy wall thickness. Near-surface resolution in any materialdepends upon the characteristics of the instrument and search unitemployed.
1.2 This guide covers the fabrication of referenceblocks for use with either the immersion or the contact method ofultrasonic examination.
1.3 Reference blocks fabricated in accordance withthis guide can be used to determine proper ultrasonic systemoperation. Area-amplitude and distance-amplitude curves can also bedetermined with these reference blocks.
1.4 This guide does not specify reference reflectorsizes or product rejection limits. It does describe typicalindustry fabrication practices and commonly applied toleranceswhere they lend clarity to the guide. In all cases of conflictbetween this guide and customer specifications, the customerspecification shall prevail.
1.5 The values stated in inch-pound units are to beregarded as standard. The values given in parentheses aremathematical conversions to SI units that are provided forinformation only and are not considered standard.
1.6 This standard does notpurport to address the safety concerns, if any, associated with itsuse. It is the responsibility of the user of this standard toestablish appropriate safety and health practices and to determinethe applicability of regulatory limitations prior touse.