Visual inspection (NDT) is an economical non-destructive testing method that involves visual examination of weld joints to check integrity and soundness. It requires a well-trained inspector to check for code compliance, workmanship, and documentation at various stages including before, during, and after welding. Visual inspection can identify surface defects but has limitations as it cannot detect internal flaws and requires inspector skill and documentation.

1. Visual
Inspection
(NDT)
By-PAWAN KUMAR
PGWLF2150056

2. Visual Inspection (NDT)
• Visual Inspection of Weld Joints
Visual examination of weld joint is an important
activity, carried out to check the integrity and
soundness of the weldment. It is an economical
activity, as it doesn’t require any costly equipment.
It must be carried out by a well experienced
inspector.
Main responsibilities of a welding inspector are:
• Code compliance
• Workmanship control
• Documentation Control

8. Requirements for visual examination
The requirements of visual examination are:
• Illumination should be at least 350 Lux (minimum) but it is
recommended to carry out visual inspection at an illumination
of more than 500 Lux.
• The inspectors eye should be within the radii of 600 mm of the
surface of item being inspected and the viewing angle must not
be less than 30 degrees.
• Welding gauges, magnifying glasses and boroscope or fibre
optic viewing system (when access is restricted)
can also be used.

9. Requirements for visual examination
Figure 1 – A typical direct view borescope

10. Stages of visual inspection
• Before Welding: The inspector shall be familiarized with
the applicable codes and standards /drawings /welding
procedures (WPS and PQR). Welder qualification shall be
carried out before production welding. The inspector shall
confirm the material and welding consumables before
welding. Joint preparation and alignment shall also to be
checked prior to welding. After confirmation of all the
parameters , the welding inspector can permit the welder
to start the production welding. If preheat is applicable,
then the preheat temperature shall be confirmed before
starting the weld.

11. Stages of visual inspection
• During Welding: The inspector shall check the
welding process and welding parameters with respect
to the welding procedure specification (WPS) at any
time during welding. Root run and root run dressing,
inter pass temperature shall be witnessed by the
inspector.

12. Stages of visual inspection
• After welding: After complete welding, identification number is
punched near joint. Complete visual inspection is done and any
surface breaking or defect shall be repaired as per approved
procedure. Following defects (or discontinuity) can be revealed by
visual inspection:
• Crack
• Underfill
• Undercut
• Surface porosity
• Overlap
• Lack of side wall fusion
• Arc strike
• Spatters
• Excessive Penetration
• Unacceptable weld profiles

14. Advantages of Visual Inspection
• Inexpensive (usually only labor expense)
• Low cost equipment
• No power requirement
• Quick identification of defects and
downstream repair costs due to issues that
weren’t caught early

15. Disadvantages of Visual Inspection
• Inspector training, knowledge and skills
are necessary
• Good eyesight required
• Can miss internal defects
• Report must be recorded by inspector
• Possibility of human error