Question

Explain why and how a range of defect sizes that can be detected for each nondestructive testing.

1. Visual Inspection

2. Liquid Penetrant

3. Magnetic Inspection

4. Ultrasonic Inspection

5. Eddy Current Inspection

6. X-Ray Inspection

Answer 1

1.) Visual Inspection

Only large size surface defects can be observed due to human eye limitation.

2.) Liquid penetration

Component is washed thoroughly and completely bathed with dye solution. Now surface is cleaned and developer is applied. Defects can be clearly identified. It is used only for surface defects.

3.) Magnetic Inspection

Only ferrous materials can be tested. Magnetic field is applied . Defects generally deflects the magnetic fields hence can be identified. Inner defects can also be detected.

4.) Ultrasonic vibration are induced in components and behavior is observed. Defects show different behavior than continuous body hence can be identified. Defects under surface can also be detected.

5.) Eddy Current Testing

Eddy-current testing (also commonly seen as eddy current testing and ECT) is one of many electromagnetic testing methods used in nondestructive testing (NDT) making use of electromagnetic induction to detect and characterize surface and sub-surface flaws in conductive materials.

6.) Inner defects can easily identified by x-ray of specimen. It is very accurate methods because inner defects are easily seen on monitor.