Visual examination is the most commonly used non-destructive testing method for inspecting welds. It involves directly or indirectly observing the exposed surfaces of welds and base metals. Proper lighting of at least 1000 Lux is needed. Various aids like mirrors, telescopes and cameras can be used. Key factors in visual inspection are the condition of the inspector's eyes, their understanding of the inspection situation, and being objective. The document discusses visual inspection guidelines and acceptance standards from codes like ASME and AWS, as well as common weld defects.

1. Presented by
Kingston R
ASME Authorized Inspector(AI)
ASNT NDT level 3 in VT,RT,PT,MT,UT,ET &LT
PCN Level 3,API 510,570,653,CSWIP 3.2 ,
NACE CIP &AWS-CWI

2. Definition : ASME – 31.1 (Visual examination)
Visual Examination:
The observation of whatever portion of components, joints and other
piping elements that are exposed to such observation either before, during
or after manufacture, fabrication,assembly,erection,inspection or testing
This examination may include verification of the applicable requirement for
materials, components, dimension, joints preparation, alignment, welding
or joining ,supports and erection.
ASME SEC-V Article –9
ASNT Hand Book
ASME SEC-VIII DIV-1 (UW-31,32,33,35,36,37,38)

3. VISUAL INSPECTION
Visual examination is the most extensively used NDE method for welds.
It includes either the direct or indirect observation of the exposed
surfaces of the weld and base metal.
Direct visual examination is conducted when access is sufficient to place
the eye within 6 in. – 24 in. (150 mm – 600 mm) of the surface to be
examined and at an angle not less than 30 degrees to the surface as
illustrated in figure.
Mirrors may be used to improve the angle of vision. Remote visual
examination may be substituted for direct examination. Remote
examination may use aids such as telescopes,borescopes, fiberscopes,
cameras or other suitable instruments, provided they have a resolution
at least equivalent to that which is attained by direct visual
examination. In either case, the illumination should be sufficient to
allow resolution of fine detail. These illumination requirements are to
be addressed in a written procedure.

4. Visual Inspection

5. AID TO VISUAL INSPECTION
 The EYE should be in good condition.
 The LIGHTING condition should be suitable(1000 Lux min.) for
the inspection purpose on hand.
 The person should have a good understanding of
the test situation .
 The person should be positively oriented to be
objective in evaluating & interpreting what is seen.

6. Welding Processes
Manual welding :
 Shielded metal arc welding (SMAW)
 Gas tungsten arc welding (GTAW)
Semi-Automatic welding:
 Gas metal arc welding (GMAW)
 Flux cored arc welding (FCAW)
Automatic welding:
 submerged arc welding (SAW)
 Electron Beam welding ( EBW)

7. Type of Joints.

8. Type of Joints

9. Symbols for various Weld Joints

10. Supplementary weld symbols

11. Standard weld symbols

12. Groove weld Nomenclature

13. Fillet weld
The normal equal leg fillet weld is expressed as the leg length of the largest
isosceles right triangle that can be inscribe with in the fillet cross section.
Throat (a) = 0.7 x Leg Length (z) or Leg Length (z) = 1.42 x Throat (a)

14. Convex Fillet Weld

15. Concave Fillet Weld

16. Main focus in engineering / fabrication
industries are on weld visual:
• Before welding
• During welding
• After welding

17. CARE TO BE TAKEN BEFORE WELDING
 Conformity to drawing dimensions
 Necessity to provide pre-weld camber/restraints (distortion
control)
 Welding procedure specification & their qualification
 Welder qualification & their applicability to the particular
situations
 Root Face
 Root Gap
 Offset or misalignment.
 Vee Angle
 Tack Quality

18. CARE TO BE TAKEN DURING WELDING
 Conformance to Welding procedure specifications
 Correctness of welding consumables
 Pre - heat Temperature
 Interpass cleaning & Temperature control
 Post heating requirements
 Weld re-enforcement planning and control
 Weld size management
 Inter-stage inspection requirements
 Preparation for NDT (Non Destructive Testing)

19. CARE TO BE TAKEN AFTER WELDING
Weld appearance & suitability for subsequent N.D.T
 Fusion with the adjacent base metal (overlap).
 Undercuts.
 Cracks- transverse, longitudinal & crater cracks or star
 Crack.
 Weld terminations & edge dressing .
 Porosities & blow holes.
 Required dimensional measurements like distortion.
 Re-inforcements, inter-bead valleys & sizing of welds.
 Joint identification & stamping requirements.
 Proper removal of cleats & dressing of the remnant areas.
 Convexity / concavity of fillet welds.

20. Common weld defects

21. Lack of penetration

22. Slag inclusion

23. porosity

24. Lack of side wall Fusion

25. Burn Through

26. Mismatch with lack of penetration

27. Excess penetration

28. Transverse Crack

29. Tungsten inclusion

30. Root pass align porosity

31. Weld Spatter
The droplets of molten material that are
generated at or near the welding arc.

32. Arc Strike
The arc is established outside of the weld area
by welded either accidently or intentionally

33. Heat Input
Q – Heat input in J/mm
V- Volt
I- Current
S-Travel speed in mm/sec
Efficiency – Manual welding = .7, Semi Automatic = .85
Automatic welding = .9 to 1

34. Type of Distortion or shrinkage

35. Controls of shrinkage

36. Controls of shrinkage

37. Optical Aids

38. Mechanical Aids

39. Weld examination Devices

40. Weld examination Devices

41. Weld examination Devices

42. Weld examination Devices

43. Weld examination Devices

44. Weld examination Devices

45. Weld examination Devices

46. Various acceptance standard for weld visual

47. Various acceptance standard for weld visual

48. Various acceptance standard for weld visual

49. Various acceptance standard for weld visual
ASNI
B 31.3

50. Various acceptance standard for weld visual
AWS D1.1

51. Various acceptance standard for weld visual
ASME SEC
VIII Div.1

52. Weld Defects
• POOR
WELD
BEAD
FINISH

53. Weld Defects
• Poor
Welding
• Spatter
• Uneven
bead

54. Weld Defects
• Poor Welding
• Incomplete
weld
• Heavy
undercuts

55. Weld Defects
•Irregular bead
•Lumps

56. Weld Defects
• ARC
STRIKES
• UNDER
CUT AT
STARTING
POINTS

57. Weld Defects
• Undercuts

58. Weld Defects
• Incomplete weld
• Spatters