ULTRASONIC TESTING

INTRODUCTION:

  • This module presents an introduction to the NDT method of ultrasonic testing.
  • Ultrasonic testing uses high frequency sound energy to conduct examinations and make measurements.
  • Ultrasonic examinations can be conducted on a wide variety of material forms including castings, forgings, welds, and composites.

A considerable amount of information about the part being examined can be collected, such as the presence of discontinuities, part or coating thickness; and acoustical properties can often be correlated to certain properties of the material

OUTLINE FOR ULTRASONIC TESTING :

  • Basic Principles of sound generation
  • Transducers
  • Instrumentation
  • Advantages and Limitations

BASIC PRINCIPLES OF SOUND:

  • Sound is produced by a vibrating body and travels in the form of a wave.
  • Sound waves travel through materials by vibrating the particles that make up the material.
  • The pitch of the sound is determined by the  frequency of the wave  (vibrations or cycles  completed in a certain
    period of time).
  • Ultrasound is sound with a pitch too high to be detected by the human ear.

ULTRASONIC GENERATION IN ULTRASONIC TESTING:

              Ultrasound is generated with a transducer in ultrasonic testing.

PRINCIPLES OF ULTRASONIC GENERATIION:

  • Ultrasonic waves are introduced into a material where they travel in a straight line and at a constant speed until they encounter a surface.
  • At surface interfaces some of the wave energy is reflected and some is transmitted.
  • The amount of reflected or transmitted energy can be detected and provides information about the size of the reflector.

TRANSDUCERS IN ULTRASONIC TESTING:

  • Transducers are manufactured in a variety of forms, shapes and sizes for varying applications.
Ultrasonic testing

Transducer

INSTRUMENTATION IN ULTRASONIC TESTING:

  • In Ultrasonic testing, Ultrasonic equipment is usually purchased to satisfy specific inspection needs, some users may purchase general purpose equipment to fulfill a number of inspection applications.
Ultrasonic testing

Instrument

ADVANTAGES OF ULTRASONIC TESTING:

  • Ultrasonic testing is sensitive to small discontinuities both surface and subsurface.
  • Depth of penetration for flaw detection or measurement is superior to other methods.
  • Only single-sided access is needed when pulse-echo technique is used.
  • Ultrasonic testing has high accuracy in determining reflector position and estimating size and shape.
  • Minimal part preparation required.
  • In Ultrasonic testing, Electronic equipment provides instantaneous results.
  • Detailed images can be produced with automated systems.
  • Has other uses such as thickness measurements, in addition to flaw detection.

LIMITATIONS OF ULTRASONIC TESTING:

  • In Ultrasonic testing, surface must be accessible to transmit ultrasound.
  • Skill and training is more extensive than with some other methods.
  • Ultrasonic testing normally requires a coupling medium to promote transfer of sound energy into test specimen.
  • Materials that are rough, irregular in shape, very small, exceptionally thin or not homogeneous are difficult to inspect.
  • Cast iron and other coarse grained materials are difficult to inspect in ultrasonic testing  due to low sound transmission and high signal noise.
  • Linear defects oriented parallel to the sound beam may go undetected.
  • Reference standards are required for both equipment calibration, and characterization of flaws in Ultrasonic testing.

To Learn Ultrasonic Testing Kindly Contact Us…

 

Leave a Reply

Your email address will not be published.