Dear Rana
Carefully read below mentioned details for your information.
ULTRASONIC TESTING
UT is used to locate surface and sub surface defects in many materials plastics and wood. It is also used to measure the thickness of the materials
ADVANTAGES OF UT
1. It is sensitive to both surface and sub surface discontinuities.
2. The depth of penetration for flaw detection is superior to other NDT method.
3. Only single sided access is needed when the pulse –echo technique is used.
4. It is high accuracy in determining and estimating size and shape.
5. Fast result and very sensitive to planar type discontinuity.
6. Applicable for thick materials
DISADVANTAGES OF UT
1. Surface must be accessible to transmit ultrasound
2. Skill and training is more extensive than with other methods.
3. It normally requires a coupling medium ( except LR UT) to promote transfer of sound energy into the test specimen.
4. Materials that are rough irregular in shape very small, exceptionally, thin or not homogeneous are difficult to inspect.
5. Cast iron and other course grained 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.
8. Not capable of detecting defect whose plane is parallel to the direction of sound beam.
RADIOGRAPHY TESTING
The radiation used in radiography testing is a higher energy version of the electromagnetic waves .The radiation can come from an X-Ray generator or a radioactive source.
ADVANTAGES OF RT
1. Used to inspect almost any material for surface and sub surface defects.
2. It can also be used to locates and measures internal features, confirm the location of hidden parts in an assembly.
3. Ability to inspect complex shapes and multi-layered structures without disassembly.
4. Minimum part preparation is required.
5. Capable of exposing fabrication errors at different stages of fabrication
DISADVANTAGES OF RT
1. Extensive operator training and skill required.
2. Access to both sides of the structure is usually required.
3. Orientation of radiation beam to non volumetric defects is critical.
4. Higher thickness radiography can be time consuming.
5. High experience need to proper interpretation of results.
6. Time consuming for result.
7. RT film is a permanent record of testing in the form of hard report.
8. Two dimensional image of defect is much easier and clear to interpret.
9. Job temperature should not exceed 60Deg .
10. Film is very sensitive to temperature, pressure and humidity.
Regards
Madhusoodhanan Nair.G
09967901872
Sr Inspector (VCS Quality Services Pvt Ltd,Mumbai)
Pls explain in brief about Acceptance criteria comparison for RT,UT, PT (Casting/ Forging) as per ASME, EN,ASTM standards?--
On Friday, July 4, 2008 12:23:26 PM UTC+5:30, vhr...@gmail.com wrote:Dear All,We awared Hydro power project. There is specifically requirments of NDT method RT for all weld joint ( i.e for all class of joint ).We never used RT in normal practice for all project. Now for convince to client We required comparision sheet between RT & UT to justifying UT is better than RT.Request to send Comparision of RT & UT. Please send comparision & revert back soon. We have to submitt QAP urgentely.Regards,Vikas Rana
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