1. Tubular Non Destructive Techniques Submitted to: Dr. Ravi Prakash Presented by: Akshay Mistri

2. Various techniques for testing of tubes I. Remote Field testing II. Eddy Current testing III.Internal Rotary Inspection system IV.Magnetic Flux Leakage testing 3. Introduction to Remote Field Testing Used to inspect ferromagnetic materials. Uses a probe which is inserted into the tube. Probe contains an exciter coil and a receiving coil , with exciter coil generating a magnetic field. 4. Probe used for testing 5. Theory of operation Probe is pulled through the tube. As the probe is pulled, magnetic field of exciter coil creates eddy currents in the tube. 6. This eddy currents creates another magnetic field of its own. Exciter field is dominant but eddy current fields extends more in the tube. Theory of operation (Contd.) 7. Theory of operation (Contd.) Magnetic field lines of eddy currents is cut by the moving receiving coil (as the probe is pulled). This produces an emf in the receiving coil. Monitoring the voltage induced in receiving coil can help in detection of flaws in the specimen. 8. The resultant field strength is shown by the green graph. This is maximum near the inner dia. And changes abruptly in the transition zone. 9. Field Zones Direct coupling zone is area where there is strong eddy current. Transition zone is area of importance. Remote field zone starts approx. two tube diameters away from exciter coil. 10. Detection of flaw When there is no flaw, phase of receiver signal w.r.t phase of exciter signal is directly proportional to sum of wall thickness within inspection area. Whenever a flaw is met, amplitude changes will occur and flaw can be detected. Flaw may be corrosion pitting, cracks or erosion thinning. 11. Instruments used 12. Result Observed 13. Introduction to Internal Rotary Inspection System (IRIS) Ultrasonic method for inspecting pipes and tubes. Can be used for both ferromagnetic as well as non- ferromagnetic materials. Produces very accurate results (up to 3%). 14. Probe Used for IRIS 15. Theory of operation Before the test, the tube is needed to be cleaned from inside (Descaling). Then it must be flooded with water. IRIS probe is then inserted in the tube flooded with water. The probe consists of a ultrasonic transducer which directs an ultrasonic beam towards a mirror which is inclined at 45 with the tube axis. 16. Theory of operation (Contd.) The probe consists of a ultrasonic transducer which directs an ultrasonic beam towards a mirror which is inclined at 45 with the tube axis. The beam falls on tube surface at right angles. The beam is partly reflected from inner surface and partly transmitted and again reflected from outer diameter surface. Time difference between the two signals is used to measure the wall thickness. 17. Theory of operation (Contd.) Also, the mirror is mounted on water driven turbine rotating at 2000 RPM. As the probe is pulled through the tube slowly, whole of the tube surface is tested. For better understanding see the video in next slide. 18. Theory of operation (Contd.) 19. Result Interpretation There are 150 readings per revolution and about 2000 revolutions per minute. The interface screen shows three results for better understanding of the situation. These are : B scan (Gives 2D display of transverse cut at any location of the tube length.) C scan (Gives plan view when tube is rolled out flat.) D scan (Gives 2D display of longitudinal cut at any circumferential position. 20. Interface screen 21. Some facts about IRIS Used for detecting pitting, corrosion and wall thickness. It is difficult to detect cracks (Special probe design is needed). Can be used only on tubes with tube diameter 13 mm or above. For accurate results, probe must be moved very slowly (2.5 cm/sec). A supply of clean water at 400 kPa is required. 22. Thank You