【国外标准】 Standard Specification for Straight-Beam Ultrasonic Examination of Steel Plates

This specification covers the standard procedure and acceptance for straight-beam, pulse-echo, ultrasonic examination of rolled fully killed carbon and alloy steel plates. The equipment shall be of the pulse-echo straight beam type. Nondestructive examination of the material shall be conducted in an area free of operations that interfere with proper functioning of the equipment. The test shall be done by one of the following methods: direct contact, immersion, or liquid column coupling. Ultrasonic examination shall be made on either major surface of the plate. Grid scanning shall be continuous along perpendicular grid lines or shall be continuous along parallel paths, transverse to the major plate axis, or shall be continuous along parallel paths, parallel to the major plate axis, or smaller centers. Any discontinuity indication causing a total loss of back reflection which cannot be contained within a circle is unacceptable.1.1 This specification2 covers the procedure and acceptance standards for straight-beam, pulse-echo, ultrasonic examination of rolled fully killed carbon and alloy steel plates, 1/2 in. [12.5 mm] and over in thickness. It was developed to assure delivery of steel plates free of gross internal discontinuities such as pipe, ruptures, or laminations and is to be used whenever the inquiry, contract, order, or specification states that the plates are to be subjected to ultrasonic examination.1.2 Individuals performing examinations in accordance with this specification shall be qualified and certified in accordance with the requirements of the latest edition of ASNT SNT-TC-1A or an equivalent accepted standard. An equivalent standard is one which covers the qualification and certification of ultrasonic nondestructive examination candidates and which is acceptable to the purchaser.1.3 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents, therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the specification.1.4 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.