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适用范围：<p id="s00002">1.1 This practice describes general ultrasonic testing procedures for the detection of discontinuities in the weld and adjacent heat affected zones of welded pipe and tubing by scanning with relative motion between the search unit and pipe or tube. When contact or unfocused immersion search units are employed, this practice is intended for tubular products having specified outside diameters <span class=''unicode''>x2265;</span>2 in. (<span class=''unicode''>x2265;</span>50 mm) and specified wall thicknesses of <small>¹/₈</small>to 1<small>¹/₁₆</small> in. (3 to 27 mm). When properly focused immersion search units are employed, this practice may also be applied to material of smaller diameter and thinner wall.</p> <p class="desc" id="N00001"> <span class="smallcap">Note</span> 18212;When contact or unfocused immersion search units are used, precautions should be exercised when examining pipes or tubes near the lower specified limits. Certain combinations of search unit size, frequency, thin<span class=''unicode''>x2013;</span>wall thicknesses, and small diameters could cause generation of unwanted sound waves that may produce erroneous examination results.</p> <p id="s00057">1.2 All surfaces of material to be examined in accordance with this practice shall be clean from scale, dirt, burrs, slag, spatter or other conditions that would interfere with the examination results. The configuration of the weld must be such that interfering signals are not generated by reflections from it. Treatment of the inner surface and outer surface weld beads such as trimming (<span class=''unicode''>x201C;</span>scarfing<span class=''unicode''>x201D;</span>) or rolling is often required to remove protuberances that could result in spurious reflections.</p> <p id="s00003">1.3 This practice does not establish acceptance criteria, they must be specified by the using parties. </p> <p id="s00004">1.4 The values stated in inch-pound units are to be regarded as the standard. The SI equivalents are in parentheses and may be approximate.</p> <p id="s00005">1.5 <span class="italic">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 and health practices and determine the applicability of regulatory limitations prior to use.</span>