T9074-AS-GIB-010/271 Rev 1
pattern shall be 8 inches square. Grid patterns as specified herein shall prevail unless modified by the contract, order, or material specification. If an unacceptable indication is obtained, the adjacent area shall be scanned in a 1-foot radius circle by the continuous method to determine the extent and magnitude of the defective condition.
6.6.3 Pipes and Tubes.
6.6.3.1 Scanning Technique. Pipe and tube shall be tested, using the continuous shear wave scan method as specified in 6.6.1.1.1.2 for radial type discontinuities extending longitudinally. Transverse discontinuity tests and additional circular tests shall be performed only when and as specified. When specifically invoked, 6.6.1.1.2 shall apply. 6.6.3.2 Test Calibration, Radial Defects Detection. Select a length of pipe or tube of acoustically similar and ultrasonically sound material and the same nominal size as the pipe or tube to be tested for use as a calibration standard. For calibration in testing for radial defects, two notches shall be cut; one on the inside surface and one on the outside surface as specified in 6.6.1.1.1.1. The notches shall be located at least 1½ inches from one end of sample. The notch shall be cut in such a manner that its sides are smooth, radial and extend parallel to each other and to the longitudinal axis of the pipe or tube. Magnitude of the indication for the notches shall be determined by directing sound waves circumferentially toward the notches with the search unit located at a suitable radial arc displacement using not less than one full skip technique where possible (see figure 6-1). If the indications from the inside and outside notches are unequal, small adjustments shall be made in the angle of incidence to equalize them. If the indications cannot be equalized, the smaller indication shall be used as the basis for evaluation. 6.6.3.3 Test, Radial Defects. When testing pipe and tubes, they shall be set with the longitudinal axis in a horizontal position on motorized rollers or other suitable mounting that permit rotation of the pipe or tube about the longitudinal axis. Rotation shall be controlled at a fairly uniform speed, depending upon the repetition rates established for the test unit being employed. In any case, the peripheral speed shall not be greater than the maximum speed at which the calibration standard is rotated for clear definite resolution of the notch being presented. When the immersion method is used, the test conditions shall duplicate calibration conditions especially in regard to keeping the tube bore filled or dry during test. In general, excluding the immersion fluid from the tube bore improves the reproducibility of test results.
6.6.4 Ultrasonic Inspection of Weldments.
6.6.4.1 Scope. This section contains the minimum requirements for the inspection of structural butt, corner, and tee welds to ensure joint integrity as required by specifications, contracts and acquisition documents.
6.6.4.2 General Requirements.
6.6.4.2.1 Application. Requirements are provided herein for the volumetric inspection of butt, corner, and tee welds (see 6.6.4.3). Requirements are also provided for tee welds that are not volumetrically inspected (6.6.4.4). The application shall be as invoked by the primary specification. 6.6.4.2.2 Surface Finish. Welds may be inspected in the as-welded condition, provided the required test sensitivity and inspection coverage can be maintained. The weld reinforcement shall be ground flush to provide a flat surface when ultrasonic inspection is to be accomplished by scanning on the weld surface. 6.6.4.2.3 Limitations. The requirements of this section were developed for the inspection of welded joints in ship hull structures. These joints consist of butt, corner, and tee design in HY-80, HTS and similar materials having thicknesses of ¼ inch and greater. The use of these requirements on other materials, other thicknesses, or other joint designs shall be reviewed for applicability of test sensitivity and technique by the Examiner and demonstrated to the authorized representative of NAVSEA.
6.6.4.2.4 Calibration Standards.
6.6.4.2.4.1 Butt Welds, Corner Welds, Tee Welds for Discontinuities into the Through Member, and Tee Weld Volumetric Inspection. The calibration standards shall be acoustically similar material as that to be inspected, and shall be
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