What Is Non-destructive Testing?
Non-destructive testing (NDT) also known as ‘positive testing’.
As its name implies, non-destructive testing means testing of materials without destroying them.
It is a kind of a testing approach in which the testing is performed to cover only the positive cases to confirm that the software behaves properly and returns the expected results as per the product requirement. It is one of the best courses to do if you want to get a high profile job in abroad or India in oil & gas, petroleum, aircraft, refinery, etc. It is commonly used in the area of aerospace engineering, mechanical engineering, civil engineering, electrical engineering, system engineering, and medicines.
EXAMPLES OF DESTRUCTIVE TEST:
Tensile test
Compression test
Shear test
Hardness test
Impact test
Fatigue test
Bending test
Creep test
Torsion test
Chemical test, etc.
IMPORTANCE OD NDT:
Save both time and money in product evaluation.
It can be used to detect flaws in an in-process machine part.
No requirements for special equipment
BASIC ELEMENTS OF NDT:
Source
Modification
Detection
Indication
Interpretation
SOME OF THE METHODS OF NDT:
Advantages:
Generally fast test time
Can be automated
Good at finding dimensional flaws or surface blemishes
Portable
Disadvantages:
Reference standards required
May require multiple cameras and viewing angles for automated systems
Subject to operator interpretation if not automated
Dye Penetrant Testing (DPT):
Advantages:
Non-destructive testing of concrete helps in detecting the surface cracks or defects.
One of the most widely used NDT testing methods.
It is used for surface detection of casting, weld elements.
It is also called liquid penetrant testing.
Disadvantages:
The defect must be open to the surface
Parts must be cleaned before and after testing
Surface films, such as coatings, scale, and smeared metal may visually mask defects
Magnetic Particle Testing (MPT):
Advantages:
Economically and easy to perform.
Portable for field testing.
Fast for production testing.
Relatively simple method.
Low cost.
Disadvantages:
· Ferromagnetic materials only
· Alignment of the magnetic field is critical
· Demagnetization required after the test
· Surface coatings can mask defects
· Pre- and post-cleaning necessary
· Messy
· Subjective: dependent on operator interpretation
· Difficult to automate
Advantages
· It is an electronic device that can produce high-frequency ultrasonic energy.
· It introduced and propagates through the materials in the form of waves.
· Portable.
· Instant test results don’t take too much time.
· It is fully capable of being automated.
· A probe is used.
· Immediate results.
Disadvantages:
Couplant required
Complex or small parts may be difficult to check
The defect may be missed if not in the path of the ultrasonic signal
Reference standards required
Trained operators for manual inspections
Special probes
Surface condition
Eddy Current Testing (ECT):
Advantages:
Equipment is very portable.
Detect surface and near-surface defects.
Deep penetration is limited.
High speed.
Low cost.
Disadvantages:
Conductive material only.
Shallow depth of penetration.
Surface roughness may affect test quality.
Radiography Testing (RT):
Advantages:
· It is having a fast method of testing.
· It is the same as medical radiography, which only differs in wavelength.
· Lessor no manual work.
Disadvantages:
Radiation hazard.
Expensive.
Trained operators needed.
Linear defects may be missed.
Depth of defect not indicated.
MAIN OBJECTIVE OF NDT:
To detect internal or surface flaws.
To measure the dimensions of the specimen.
To determine material structure or chemistry.
To evaluate the material’s physical or mechanical properties.
ADVANTAGES OF NDT:
The equipment is easy to handle.
The data is more recordable and more repeatable.
Methods are quick and accurate.
Defects can be detected without damaging the components.
It can be done on small instances of the code to confirm it is ready to be merged into the main code, thus reducing the chances of it breaking the code.
No extra tools or equipment are required to do NDT.
Less Skill and non-expensive.
It is used for finding out the defects.
The Specimen is not damaged during testing.
It provides reliability.
Harmless to humans.
DISADVANTAGES OF NDT:
Purchase costs may be preventative, so renting can be a preferable option.
Due to load applications, the material gets damaged. Sometimes there might be a lack of depth sizing
On some non-destructive test methods, only relatively heavy surfaces can be inspected.
Some test methods require electricity.
Some can also be affected by variations in magnetic permeability.
Some tests are only effective in conductive materials.
The methods take time and rarely be finished in less than 30 minutes.
Components needing to be cleaned before and after inspection.
APPLICATIONS OF NDT
To ensure product reliability
To control the manufacturing process
To lower production cost.
Inspection of raw products i.e. forgings, castings, extrusions, etc.
WHERE TO USE NDT:
In product evaluation.
For troubleshooting
For identifying areas of wear
For assuring the safety and reliability of structures and component
To find flaws or irregularities both on and under the surface of materials.
NDT is used in many industries, including:
Engineering
Air
Space
Rail
Motor vehicles
Utilities
Power and energy companies
Construction
CONCLUSION:
Non Destructive Testing provides cost-effective and reliable analysis under realistic conditions. Each NDT Testing services has certain capabilities and limitations and often more than one technique is used to cover various parts. Increasing the availability of robotic scanners improve the speed of testing large surfaces, hence minimizing the testing time.
Contact the Sigma Team
Website:- https://www.sigmatest.org
Call on this number +91-9560222333
Mail ID- mail@sigmatest.org
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