Understanding Non-Destructive Testing: How It Enhances Safety and Reliability in Industry

Non-Destructive Test (NDT) Checks

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

- To find out the internal soundness of metal, surface defects, and inspect for incorrect assembly where stripping is not possible, non-destructive tests are carried out on metals.
- NDT helps in saving man-hours, reducing unserviceability time of equipment, and allowing more frequent and thorough examination, thus increasing industrial safety.
- NDT makes components more reliable, safe, and economical and helps in maintaining a high standard of serviceability.
- 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 destructive tests.
- NDT is the generic title for those methods of testing, examination, or inspection that do not render a material, equipment, system, or structure unfit for future use. NDT improves safety standards, increases equipment availability, and reduces servicing costs. Due to its reliability, cost-effectiveness, and importance in health assessment, more and more NDT techniques/equipment are being used in many industries. It is therefore important that the knowledge and skills of the technician are improved in this sphere of activity.
- NDT helps in the detection of inherent defects (e.g., 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 the defect.

Detection Methods

There are many flaw detection methods in current use. The methodology of certain common techniques is given below:

- Visual Inspection
- Dye-Penetrate
- Eddy Current
- Ultrasonic
- Radiography/X-ray
- Endoscope/Fiberscope
- Magnetic Particles Technique

Good info shared, Mr. Bhaskar. I really appreciate you for posting this information so that everyone will be aware of defects in metals. Thanks for sharing 

Dear Varsha, this Non-Destructive Test is being carried out in major industries and even in Defense Establishments where the manufacturing process or major overhauling is conducted for the equipment and vessels/aircraft. Crack detection and variations in the thickness of welding can be easily identified through this test without significant cost implications, ensuring industrial safety and helping to prevent major breakdowns.

Thanks for your comments, Varsha.

Dear Bhaskar,
Thank you for sharing a very valuable article on NDT checks. The article provides a summary of what NDT checks mean. As usual, you have shared a valuable message that will be very useful for all technology users. With the advent of IT, most of us do not bother to know about other technologies. Without Physics and Mechanical engineering, no technology, not even household activities, would survive. I am glad you have shared excellent information on a non-IT subject.

Pros and Cons of NDT Methods
On my part, I will add the pros and cons of the methods used for the NDT tests, which will be useful to all concerned.

Please use the following link to view the message: http://www.ndt-ed.org/GeneralResourc...hodSummary.htm

Regards,
AVS

Destructive Testing and Its Importance

NDT is primary, but destructive testing is essential to understand the physical properties such as tensile test, compressive test, etc. The Universal Testing Machine is used for DT. Chemical properties also need to be examined. In the case of any metal, a carbon content test is crucial to qualify for welding procedures.

I am not a QC man, but I have some knowledge about it.

Regards,
Pon

Thank you for initiating such an informative thread. Good sharing by others makes this a great reference regarding NDT. Thanks and keep on sharing.

Regards.

Importance of Non-Destructive Testing (NDT)

First of all, I am very sorry for the late reply! 

We use NDT because it best solves the problem of usefulness and 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 neither provide 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 a 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 lowest bidder when the vehicle has not undergone 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. These are good reasons for us to use it.

Again, thanks, Bro!

Regards

Hi Bhaskar, just wondering, does NDT apply as a term only to metal or to other things as well? Under the Factory Act, all pressure vessels are required to be tested every year: every 6 months for visual inspection, hydraulic testing once a year, and ultrasonic testing for cracks every 4 years. Additionally, all lifts and hoists are tested every year.

Thank you, Mr. AVS, for your valuable addition, which provides more information on the types of NDT tests, their advantages, and disadvantages.

Thank you, Mr. Ponraj, for sharing details about destructive testing. In many cases, we cannot afford the damage or further damage to the equipment/vessels/aircraft because we are not manufacturing the same and only importing, and its cost-effectiveness has led us to carry out NDT tests to check its serviceability.

Thank you, Mr. Dipil, for your valuable feedback.

Thank you, Mr. Raghu, for sharing such a useful addition to this thread about the purpose of NDT checks.

Dear Mr. Saswata Banerjee, even though I am a law-qualified person, I have not come across the details you have shared. Thanks for educating us about the legal requirements regarding NDT checks as per the Factories Act.

Relevance of NDT in Safety Forums

I was really wondering how a purely QC issue of NDT found its place in a safety forum. If there is no safety concern, what relevance does it have? In fact, all those NDT procedures are not that safe; they have very serious safety concerns! For example, consider "industrial radiography." How serious a matter is it for a safety professional?

• Can you just get an "isotope" or "source," as we call it, and bring it to do radiography on your welded pipes?

• Is a permit required to have a source or not?

• If a permit is required, who is the authority to issue it?

• What are the typical permit conditions?

• How will you store a source at your premises?

• Are there any rules for transporting a radiation source?

• Are there specific conditions in the permit for storage and the storage facility?

• Who should have control over the source?

• What are the safety precautions stipulated for conducting industrial radiography?

• What are the safety precautions stipulated for conducting radiography at a workplace where other employees are present?

• What qualifications are required for a radiographer, if any?

• What is the role of a person called a radiation safety officer?

• What personal protective equipment is required for an industrial radiographer?

• What medical surveillance is necessary for a radiographer?

• In case of a radiation accident, what actions should be taken?

• What about the safety in the darkroom used by a radiographer?

• What about the safety of chemicals used in processing, if they use chemicals?

• How will you dispose of the waste and used chemicals from radiography?

There are more questions to be answered. Now, can you say all those NDT procedures are to improve occupational safety or purely quality assurance?

Regards,
Kesava Pillai

Dear Mr. Kesava Pillai, I have forwarded your questions to the Safety Manager of our construction site, as we are using radiography to test the welding quality in a Steel Melting Shop and Heavy Forgings Shop Factory. Upon receipt of his reply, we can gain some insight into the radiography test for welding. Thank you for your questions; knowledge develops when questions are posed. Please continue to enlighten us with your wisdom, Mr. Kesava Pillai.