NEW NONDESTRUCTIVE TESTING SYSTEM FOR HIGH-QUALITY OIL-COUNTRY TUBULAR GOODS.

Improvement was required of the nondestructive testing system of the Wakayama Seamless Tube Mill because of the production of higher-quality tubes, used mainly under conditions such as in deep wells, sour gas wells and frigid-zone wells. Recently a new nondestructive testing system has been developed. The features of the system are as follows: (1) Various inspection machines are applied in order to reinforce each other. (2) The surface of a pipe is scanned entirely by sensors at production speed. (3) Pits are detected as well as cracks and seams by both probe eddy currents and compound magnetic inspection machines that have been developed. (4) Inspection sensitivity is high enough to detect defects of 5% of the depth of wall thickness. (5) Each inspection machine is equipped with micro-computers or personal computers for automatic processing.