This document provides an overview of non-destructive testing (NDT) methods, focusing on visual inspection. It defines visual inspection as the oldest and most basic NDT method, using only the naked eye to look for flaws. The document distinguishes between unaided visual inspection, using only the eye, and aided visual inspection, which employs optical or mechanical instruments like borescopes, microscopes, calipers and feeler gauges to enhance inspection capabilities. It provides examples of different optical and mechanical aids used to conduct aided visual inspections.

1. Module-1:Overview of NDT
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Prepared by
Mr.M.Mani Vannan
Assistant Professor
Department of Mechanical Engineering

2. 1.Able to identify difference between aided and unaided
inspection.
2.Able to explain the different aided inspection methods.
3.Able to explain the different unaided inspection
methods.
2Visual Inspection

3. Visual Inspection, or Visual Testing (VT), is the oldest
and most basic method of inspection. It is the process
of looking over a piece of equipment using the naked
eye to look for flaws. It requires no equipment except
the naked eye of a trained inspector.
 Visual inspection can be used for internal and external
surface inspection of a variety of equipment types,
including storage tanks, pressure vessels, piping, and
other equipment.
3Visual Inspection

4. 1.Unaided Visual Inspection-Inspection without use of
any optical or mechanical instruments.
2.Aided Visual Inspection-Inspection with use of any
optical or mechanical instruments.
4Visual Inspection

5. When a inspection of speciment or part is carried
without the use of any opto-electrical or electronics
devices is called unaided visual inspection.
5Visual Inspection

6. 6Visual Inspection

7. 7Visual Inspection

8. Optical Aids Mechanical Aids
1.Microscopes 1.Micrometers
2.Borescopes 2.Calipers
3.Fiberscopes 3.Depth gauges
4.Video Cameras 4.Thread pitch gauges
5.Feeler gauges
6.Weld gauges
8Visual Inspection

9. 9Visual Inspection

10. 10Visual Inspection

11. 11Visual Inspection

12. 1.A borescope is an optical device consisting of a rigid or
flexible tube with an eyepiece on one end, an objective
lens on the other linked together by a relay optical
system in between.
2.The optical system in some instances is surrounded by
optical fibers used for illumination of the remote object.
3.An internal image of the illuminated object is formed
by the objective lens and magnified by the eyepiece
which presents it to the viewer's eye.
12Visual Inspection

13. 13Visual Inspection

14. 14Visual Inspection

15. 1.A feeler gauge is a tool used to measure gap widths.
2.Feeler gauges are mostly used in engineering to
measure the clearance between two parts.
15Visual Inspection

16. A set of templates for the legs of the angular control of
welded joints as well as for measuring the convexity and
concavity of the seam.
16Visual Inspection

17. 17Visual Inspection

18. 18Visual Inspection

19. 19Visual Inspection

20. 1.Visual Inspection
2.Types of Visual Inspection
3.Unaided visual inspection
4.Aided visual inspection
5.Instruments used in aided visual inspection
20Visual Inspection

21. THANK YOU
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