Tuesday, 12 July 2016

Advantages and limitation of ultrasonic testing.

 ADVANTAGES OF ULTRASONIC INSPECTION: -                                                                           1)   It is sensitive to both surface and subsurface discontinuities.       
2)   The depth of penetration for flaw detection or measurment is superior to the NDT methods.
3)   Only single sided access is needed when the pulse echo technique is used.
4)   It is highly accurate in determining reflector position and estimating size and shape.                                   5)   Minimal part preparation is requirerd.                                                                                                   6)   Electronic equipment provides instantaneous results.                                                                             7)   Detailed images can be produced with auotmated systems.                                                                      8)   It has other uses,such as thickness measurement,in addition to flaw detection.                                        
1)   Surface must be accessible to transmit ultrasound.                                                                                   2)   skill and training is more extensive than with some other methods.                                                           3)   It normally requires a coupling medium to promote the transfer of sound energy into the test specimen.     4)  Materials that are rough, irreguler in shape,very small,exceptionally thin or not homogenous are difficult . 5)   Cast iron and other coarse gained materials are difficult to inspect due to low sound transmission and       high signal noise.                                                                                                                                          6)  Linear defects oriented parallel to the sound beam may go undetected.                                                   7)  Reference standards are required for both equipment calibration and characterization of flaws.