Covers ferrous pipes of not less than 12.5 mm outside diameter and with a K factor (outside diameter divided by inside diameter) not greater than 2. It is applicable to both seamless and welded pipes having a nominal thickness of not less than 1.5 mm and describes appropriate ultrasonic techniques for the detection of imperfections. This part is confined to the ultrasonic examination of the weld zone in longitudinally and spirally welded pipes. Specifications which require tests to be carried out in accordance with this part should state whether tubes which are welded and subsequently worked during manufacture are to be treated as seamless or welded.