ULTRA SONIC TESTING:-

2.2.1     ULTRA   SONIC TESTING:-

High frequency sound waves are introduced into a material and they are reflected back from surfaces or flaws. Reflected sound energy is displayed verses time and inspector can visualize a cross section of the specimen and showing depth of defect.

MAIN USES

It used to locate surface and subsurface defect in many materials including metals, plastic and wood. UT is also used to measure the thickness of the material and otherwise characterized property of material based on sound velocity measurement.

Equipment used in RT-

1.      Ultrasonic Machine

2.      Probe

3.      Reference Gauge

4.      Couplant

Procedure-

1.      Set the machine for proper thickness and set the velocity for the given material.

2.      Apply the coupler on components surface

3.      Get the reading on LED screen by moving the probe on the surface of component.

4.      If we observe the fluctuation in graph then, defect may be present.

Advantages of UT:

1.      Sensitive to both surface and subsurface

2.      Depth of penetration for flow detection or measurement is superior to other NDT methods.

3.      Only single sided access is needed.

4.      Minimum part preparationisrequired and provide instantaneous result.

Disadvantages of UT:

1.      Surface must be accessible to transmit ultrasound.

2.      Skill and training is more extensive than with some other method.

3.      It required Couplant medium is required to promote transfer of sound energy into test specimen.

4.      Rough material difficult to inspect.