boss2966
1168

Non Destructive Test (NDT) Checks

The NDT checks are mainly carried out to study the mechanical property of metal. These tests are carried out

(a) To find out the internal soundness of a metal to know surface defects and inspect for an incorrect assembly where stripping is not possible, non destructive tests are carried out on metals.

(b) NDT help in saving man hours, reduction in unserviceability time of equipments and allows more frequent and thorough examination, thus increasing industrial safety.

(c) NDT makes component more reliable, safe and economical and help in maintaining high standard of serviceability.

(d) The tests can be applied to metals in their raw state, before or after machining and during the entire life of a component in use thus these tests are more reliable than the destructive tests.

(e) NDT is the generic title for those methods of testing, examination or inspection, which do not render a material, equipment, system or a structure unfit for future use. NDT improves the safety standards, increases the equipment availability and reduces servicing cost. Due to its reliability, cost effectiveness and importance in health assessment, more and more NDT Techniques / Equipments are being used in many industries. It is therefore important that knowledge and skill of the technician is improved in this sphere of activity.

(f) NDT helps in detection of inherent defects (eg. Variation in grain size, chemical composition, processing defects (porosity, machining, plating) and service defects (fatigue, pitting and cracks). The selection of technique depends on the types of material, shape, size, location of the item, and possible defects that need to be assessed. Each technique has its own merits and demerits. A combination of one or more techniques can also be used depending on the nature of defect.

Detection Methods : There are many flaw detection methods in current use. Methodology of certain common techniques is given below:-

(a) Visual Inspection

(b) Dye-Penetrate

(c) Eddy Current

(d) Ultra Sonic

(e) Radiography / X-ray

(f) Endoscope / Fibrescope

(g) Magnetic Particles Technique

From India, Kumbakonam
amirtha12varshini
20

Good Info shared Mr.Bhaskar,. I really appreciate you for posting this stuff so that every one will be aware of defects in Metals.Thanks for sharing :)
From India, Coimbatore
boss2966
1168

Dear Varsha
This Non Destructive Test is being carried out in major industries and even in Defence Establishment where the Manufacturing process or major Overhauling is carried out for the equipments and vessels/aircrafts. For Crack Detection and the variation in thickness of welding is easily identified and can be carried out without much cost implication, so that the Industrial Safety is ensured and major breakdown can be avoided by this NDT Tests.
Thanks for your comments Varsha.

From India, Kumbakonam
avsjai
456

Dear Bhaskar
Thanks for sharing a very valuable article on NDT checks. The article gives a summary of what NDP check means. As usual you have shared a valuable message which will be very useful for all technology users.
With the advant of IT most of us does not bother to know the other technologies. With out Physics and Mechnical engineering no technology even house hold activites will survive.
I am glad you have shared an excellent information on a non-IT subject.
From my part I just add the pros and cons of the method used for the NDT tests which will be useful to all concerned.
Use the below link to see the message:
NDT Method Summary
Regards
AVS

From India, Madras
pon1965
604

NDT is primary but Destructive testing is essential to know about the physical properties like tensile test, compressiove test, etc. Universal Testing Machine is used for DT. Chemical properties are also required to be carried out. In any metal, carbon content test is essential to qualify for the welding procedures.
I am not QC man but know something about it.
Pon

From India, Lucknow
dipil
713

Dear Mr. Bhaskar Thanks for initiating such a informative thread... Good sharing by others makes this a great referance regarding NDT... Thanks & Keep on sharing...
From India
raghuvaran chakkaravarthy
497

Dear Bhaskar/Boss,

First of all very sorry or late reply!! :) :)

We use NDT because it best solves the problem of usefulness, and because it makes good sense to use it. Potential good reasons include economic advantages, avoidance of physical injury, freedom from liability damages, and the desire to be known for producing goods of the highest quality. We all want what we produce or what we purchase to perform without failure for a reasonable period of time. NDT helps us do that. Destructive testing can provide neither the answer nor give us the certainty of the usefulness of a part. The highest quality of materials, fabrication, and workmanship cannot guarantee the suitability of part or system, nor produce it at a reasonable cost. NDT saves money, material, time, and even life when it is properly applied. Would you want to travel into space in a vehicle built by the low bidder, when the vehicle has not had extensive NDT? Or even use a part in an important system if there was no reason to believe that the part would function properly? Probably not! Again, we apply NDT where it makes good sense: for economics, quality, and safety. Good reasons for us to use

Again thanks Bro!!!

From United States, Fpo
saswatabanerjee
2392

Hi Bhaskar,
Just wondering,
Does ndt apply as a term only to metal or to other things also ?
Under factory act, all pressure vessels are required to be tested every year. Every 6 months for visual inspection, hydraulic testing nice a year, ultrasonic testing for cracks every 4 years.
Also all lifts and hoists are tested every year.

From India, Mumbai
boss2966
1168

Thank you Mr. AVS for your Value Addition, which gives more on the types of NDT Tests, its Advantages and Disadvantages.
Thank you Mr. Ponraj for sharing the details about Destructive Testing. In many cases we cannot afford the damage or further damage to the equipments/vessels/aircraft, because we are not manufacturing the same and only importing and its cost effectiveness made us to carry out the NDT Tests for checking its serviceability.
Thank you Mr. Dipil for your valuable feedback.
Thank you Mr. Raghu for sharing such useful addition to this thread about the purpose of NDT Check.
Dear Mr. Saswata Banerjee, Eventhough I am a law qualified person, I have not gone through about the details you have shared. Thanks for educating us about the legal requirement about the NDT Check as per Factories Act.

From India, Kumbakonam
Dharaniyuvetha
75

hmmm......
i m unaware of technical details regarding machines..........
nd bhaskar anna u hav given the article clearly that a non-technical student can also understand...........
thnks for additional info given by AVS sir,raghuvaran sir nd pon ...........

From India, Coimbatore
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