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NDE 2. Inspection and NDE 2. Learning Activities View Slides; Read Notes, Listen to lecture View Demo Do on-line workbook Do homework. Lesson Objectives When you finish this lesson you will understand: Several Other Non-destructive Testing Techniques
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Inspection and NDE 2 • Learning Activities • View Slides; • Read Notes, • Listen to lecture • View Demo • Do on-line workbook • Do homework • Lesson Objectives • When you finish this lesson you will understand: • Several Other Non-destructive Testing Techniques • Advantages and Disadvantages of each Keywords Eddy Current Testing, Ultrasonic Testing, Acoustic Emission
I=E/Z Z=Impedence Defects disturb magnetic field which changes Z, and is picked up by change in Coil current Defect must by oriented normal to induced current AWS Welding Handbook, Vol 1, 1987
AWS Welding Handbook, Vol 1, 1987
AWS Welding Handbook, Vol 1, 1987
Questions? • Turn to the person sitting next to you and discuss (1 min.): • In what circumstances might Eddy Current Testing not work well?
Nondestructive Evaluation Ultrasonic Testing • Transducer emits a beam of ultrasound which is transmitted through the sample; free surfaces or defects reflect the beam • The reflected beam is monitored on an oscilloscope • Water, grease, glycerin couple together the transducer with the metal • There is a certain skill/art involved in positioning the transducer 0.1.1.4.1.T4.95.12
Advantages of UT • Can detect discontinuities in thick sections • Has relatively high sensitivity to small discontinuities • Able to determine depth or internal discontinuity and to estimate size and shape • Can adequately inspect from one surface • Equipment can be moved to the job site • Is nonhazardous to personnel or other equipment
Limitations • Setup and operation require trained and experienced technicians • Weldments that are rough, irregular, very small or thin are difficult to inspect • Discontinuities at the surface are difficult to detect • A couplant is needed • Reference standards are necessary to calibrate
Welding Code Nondestructive Evaluation transducer defect ultrasonic wave A C Ultrasonic signal over flaw A - top surface B - flaw C - bottom surface B
High Velocity, Short wavelength Can be focused Propagated Through water Only used for inclusions and laminations Approx. 1/2 Velocity of Longitudinal Easier Electronic timing Greater Sensitivity to small defects Can get 3D info More easily dispersed Not propagated through water
Defect Size Determination Defect Length Determination
Discontinuity Orientation Discontinuity Type & Shape
Acoustic Emission • Signals Produced by: • Plastic Deformation, • Clamping/Unclamping • Loading • Thermal Stressing • Crack Propagation • Picked Up by Transducer • Monitor during welding • Arc Welding • Resistance Welding • Monitor In-Service
Demonstration Please Click on the Non-Destructive Testing Demonstration on the Demonstration Web page on the WE300 Website.