【国外标准】 Standard Specification for Straight Beam Ultrasonic Examination of Rolled Steel Structural Shapes

This specification deals with the procedures and acceptance standards for straight beam, pulse echo, ultrasonic examination of rolled structural shapes. The section surfaces shall be sufficiently clean and smooth to maintain a back reflection from the opposite side of the flanges, legs and webs. Ultrasonic testing shall be made on the major surface of each flange and one major web surface. Evaluation of indications may require inspection from an opposite surface. Two levels of acceptance standards are included. Level II is intended for normal applications where freedom from gross internal discontinuities is desired, particularly in connection regions. Level I is intended for critical applications such as welded chord members used in tension loading.1.1 This specification covers the procedure and acceptance standards for straight beam, pulse echo, ultrasonic examination of rolled structural shapes having a minimum section thickness of 1/2 in. [12.5 mm]. It was developed to ensure delivery of steel structural shapes 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 shapes are to be ultrasonically examined. Two levels of acceptance standards are included. Level II is intended for normal applications where freedom from gross internal discontinuities is desired, particularly in connection regions. Level I is intended for critical applications such as welded chord members used in tension loading, where internal discontinuities could be detrimental. Level II is normally applicable unless otherwise specified in contract documents or the purchase order. Supplementary requirements for alternative scanning coverages are provided.1.2 The values stated in either inch-pound 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.1.3 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.