The stress analysis basis used in the ASME Code to analyze the nozzle reinforcement is called Beams on Elastic Foundation (Hetenyi, 1946). This method determines the effectiveness of the material close to the opening for carrying loads. Reinforcement limits are developed parallel and perpendicular to the shell surface near the opening. Although the method is a simplified application of the elastic foundation theory, experience has shown that it does a good job. Values from two equations are used to set the reinforcement limits measured along the vessel wall surface. The greater value sets the horizontal limit for that opening. The first value is equal to d, and the second value is equal to 0.5d + t + tn as shown in Fig. 5.2. The relationship of the nozzle wall thickness

1. PowerPoint to accompany
Welding
Principles and Practices
4th edition
Edward R. Bohnart
© 2012The McGraw-Hill Companies, Inc. All rights reserved.
Chapter 28
Joint Design,
Testing, and
Inspection

2. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 2
Objectives
1. Describe various types of weld joint
designs.
2. Understand implications of doing code
welding.
3. Describe various nondestructive weld test
methods.
4. Describe various destructive weld test
methods.
5. Demonstrate ability to do groove and fillet
weld soundness tests.

3. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 3
Objectives
6. Describe and conduct visual weld
inspection.
7. Explain the various gauges used for
weld inspection.

4. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 4
Welding
• First used as means of patching and repairing
• As use switched to fabrication, it was essential
for welded joints to be strong
– Meet service requirements (fitness for purpose)
• Methods for testing quality of weld, ability of
welder, and ability of inspector devised
– Visual inspection
– Need to inspect within weld to determine reliability of
welded joint

5. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 5
Joint Design
• Five basic joints
– Butt
– Corner
– Edge
– Lap
– T
• Types of welds applied to these joints
– Fillet
– Groove

6. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 6
Open and Closed Roots
• Open roots
– Spaces between edges of member to be welded
– Used to secure complete root penetration in butt joints
and to secure attachment to backing member
• Penetration refers to depth to which base metal
melted and fused with metal of filler rod or
electrode
• Closed roots
– No space between members to be welded

7. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 7
Factors When Choosing Open
or Closed Root Set Up
• Thickness of the base metal
• Kind of joint
• Nature of the job
• Position of welding
• Type and size of electrode
• Structural importance of the joint in fabrication
• Physical properties required of weld

8. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 8
Closed and Open Roots
Closed Roots Open Roots
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

9. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 9
Edge Joints and Edge Weld
• Economical for noncode work
– Cost of penetration low
• Not suitable for sever load conditions
• Not be used if either member subject to direct
tension or bending at root
– Very deep penetration impossible
• Used only on 1/4 inch metal or thinner
• Edge weld completely consumes edges of edge
joint

10. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 10
Closed Square-groove
Butt Joint
• Can be welded in several different ways
• Preparation requires only butting together of
plate edges
• CJP of base metal necessary if used for code
edges
• Welding one side does not secure complete
joint penetration and joint weak at root
– Can be done on metal 1/8" or thinner
• Welding both sides increases joints strength
– Used on metal 3/16" or thinner

11. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 11
Closed Square-groove
Butt Joint
• For complete joint penetration
– Shielded metal arc welding used on metal 1/4"
thick
– Submerged arc welding used on metal 5/8"
thick
– On metal more than 3/16" thick, recommended
that root of first pass be chipped or gouged out
from the reverse side to sound metal before
depositing second weld

12. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 12
Closed Square-groove
Butt Joint
One side
Both sides
Material 1/8" or less
Material 3/16" or less
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

13. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 13
Open Square-groove
Butt Joints
• Penetration easier than on closed square-
groove butt joints
– Heavier sections can be welded
– One sided up to 3/16" material
– Both sides up to 1/4"
• Shielded metal arc process for metal 3/8"
thick
• Submerged arc welding for metal 3/4 thick
– Root of first pass must be chipped out to sound
metal before depositing second weld

14. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 14
Open Square-groove
Butt Joints
If joint penetration not achieved, joint
not any stronger than closed type and
has same possibility of failure under load.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Material up to 1/4"
Material 1/16" or less

15. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 15
Single V-groove Butt Joint
• Superior to square-groove butt joints
• Provide 100% penetration and better plate
edge preparation than square-groove butt
joints
– Metal preparation more costly and greater amount
of electrode deposit used in welding
• Used on plate thicknesses from 1/4" to 5/8"
• Joints welded from both sides with complete
joint penetration provide full strength and
meet requirements of code welding

16. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 16
Single V-groove Butt Joint
• Welding from both side accomplished only
where work will permit operator to weld
from both sides of plate
• Backing strip can be used
– Weld faster and use larger electrodes
– Removable back used when welding from one
side with submerged arc process
• Can weld up to 1 1/2" in thickness

17. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 17
Proportions for Single
V-groove Butt Joints
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

18. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 18
Single V-groove Butt Joints
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

19. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 19
Double V-groove Butt Joint
• Suitable for most severe load conditions
• Used on heavier plate 3/4 to 1-1/2 inch thick
• Cost of joint preparation greater than single
V-groove butt joint, but amount of filler metal
needed less
• Essential that complete root penetration be
achieved
– Work must permit welding from both sides, and
back side of the first pass must be chipped before
applying second pass from other side

20. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 20
Double V-groove Butt Joint
May be less
with wider
root opening
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

21. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 21
Beveled-groove Butt Joints
• Suggested for work where load demands
greater than can be met by square butt joints
and less than V-groove butt joints
– Join metal up to 3/4 inch thick, and less filler metal
required than for V-groove butt joint, thus reducing
number of electrodes needed
– Cost of preparation less than V-groove butt joints
since necessary to bevel only one plate edge
• For full strength root of first pass should be
chipped to sound metal before depositing
second pass

22. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 22
Beveled-groove Butt Joints
May be less
with wider
root opening
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

23. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 23
Double Bevel-groove
Butt Joint
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

24. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 24
Single Bevel-groove
Butt Joints
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

25. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 25
Single U-groove Butt Joint
• Used for very important work
• Cost of preparation greater than bevel and
V-groove butt joints, but fewer electrodes
needed
• Used on plate thicknesses from 1/2" to 3/4"
• Complete penetration necessary
– Easier to obtain when welded from both sides and
on joints with backup strip
• Joint usually welded with free-flowing
electrodes

26. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 26
Single U-groove Butt Joint
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

27. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 27
Double U-groove Butt Joint
• Used on work of same nature as single U-groove
butt joints but when plate thicknesses are greater
• Plate thicknesses range up to 3/4"
• Cost of preparation greater than single U-groove
butt joints
– Double joints may be welded with fewer electrodes
• Welding from both sides permits more even
distribution of stress and reduces distortion
• Choice between double-U and double V-groove
made on basis of relative costs of metal
preparation and welding
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

28. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 28
Double U-groove Butt Joint
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

29. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 29
J-groove Butt Joints
• Single and double used on work similar to
that requiring U-groove butt joints
– Load conditions would not be as demanding
• Cost of preparation less since only one
plate edge must be prepared
– Less filler metal required to fill groove
• Difficult to secure good fusion and
thorough penetration because of
perpendicular wall

30. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 30
J-groove Butt Joint
Single J-groove butt joints
Double J-groove butt joint
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

31. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 31
Lap Joints
• Used frequently on all kinds of work
• No plate preparation involved
• Single-fillet not as strong as double-fillet
– Used on noncode work and when joint not
subjected to bending
• Fusion to the root is necessary
• Never used to replace butt joint on work
under severe load

32. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 32
Lap Joints
Single Fillet Double Fillet
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

33. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 33
Slot and Plug Welds on a
Lap Joint
• Used infrequently
• Joint one plate or bracket to another when
desirable to conceal weld or when lack of
edge to weld on
• Requires series of these welds in order to
withstand heavy load
– Cost of preparation high
• Difficult to make welds free or porosity and
slag inclusions if slots small

34. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 34
Slot and Plug Welds on a
Lap Joint
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

35. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 35
Flush Corner Joints
• Used on light gauge sheet metal (under 12
gauge)
• No edge preparation needed and fitup
simple
• Can weld heavier plate if no bending
action at root
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

36. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 36
Half-open Corner Joints
• Used on 12-gauge to 7-gauge plate
• Forms groove and permits weld
penetration to root and good appearance
• No edge preparation required
• Fitup usually simple
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

37. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 37
Full-open Corner Joints
• Can be used on any plate thickness
– Welded one side, penetration must be secured
through root
– Welded both sides, joint
suitable for severe loads
• Good stress distribution
• No edge preparation required
• Plates must be cut absolutely square
• Used in production welding
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

38. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 38
Square-groove T-Joint
• Used on plate thicknesses up to 1/2"
• Preparation of plate not necessary
• Fitup can be fast and economical
• Electrode costs are high
• Single-fillet T-joint will not withstand
bending action at roof of weld
– If possible, weld from both sides and joint will
withstand high load conditions

39. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 39
Single Bevel-groove T-joint
• Can withstand more severe loads than square-groove
• Used on plate thicknesses ranging from 3/8 to 5/8 inch
– Plate of greater thickness welded with submerged arc
• Cost of preparation greater than for square-groove
T-joint, and fitup likely to take longer
– Electrode costs less because these are groove welds not
fillet welds
• If possible to weld from one side only, full penetration
must be obtained so bending does not cause failure
– Done from both sides, load resistance of joint materially
increased

40. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 40
Double Bevel-Groove T-Joint
• Used for heavy plate thicknesses up to 1"
• Done from both sides of plate
• May be used for severe loads
• Must make sure fusion obtained with
both flat and vertical plates
• Complete joint penetration
necessary
• More expensive than square
groove T or single bevel-groove
joint – weld time and electrode
costs less Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

41. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 41
Single J-groove T-joint
• Used for most severe load conditions
• Generally used on plates 1 inch or heavier
• If welding from one side, great care should be
taken to secure good root penetration
• If welding from both sides possible, efficiency of
joint can be increased materially by putting bead
on side opposite J
– Reduces tendency of failure at root as result of load at
this point
• Cost of plate edge preparation higher than for
bevel-groove T-joint, but saving in weld time and
electrode costs

42. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 42
Double J-groove T-joint
• Will withstand most severe load conditions
• Used on plates 1-1/4" or heavier
• Must be able to weld from both
sides of plate
• Complete joint penetration and
surface fusion essential to
prevent failure
• Plate edge preparation higher
than V-groove T-joints and single
J-groove joints
– Electrode costs lower
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

43. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 43
Code Welding
• Code – set of regulations governing all elements
of welded construction in certain industry
– Provide for human safety and protect property
against failure of weldment
• No universal testing procedure
• Pressure piping conforms to Code for Pressure
Piping of American Standards Association
• Boiler piping conforms to Code for Boilers and
Pressure Vessels, Section IX by ASME

44. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 44
Code Welding
• Welding of pipelines conforms to Standard
for Welding Pipelines and Related Facilities
– Developed by American Petroleum Institute
• Generally these standards set by federal,
state, and local governments, insurance
companies, and various professional
organizations
– AWS Structural Welding Code – Steel
– Food and Hygienic Welding Industry
– Aerospace and Ground Support Systems

45. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 45
Code Welding
• Employer (engineering and production
dept.) makes sure work meets standards
– Welder should have good understanding of
weld tests and how to do visual inspection
• Two broad categories of welding tests
– Procedure qualification
• Purpose to determine correctness of method of
welding
– Welder qualification or performance
qualification
• Purpose to see if welder has knowledge and skill

46. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 46
Code Welding
• Methods of testing determine quality of
weld divided into three very broad
classifications
– Nondestructive testing
• Does not damage weld or finished product
– Destructive testing or mechanical testing
• Requires test specimen be taken from fabrication
• Weld damaged beyond use
– Visual testing
• Surface of weld and base metal observed for
visual imperfections
• Which should be the first inspection method used

47. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 47
Code Welding Example
Recommended dimensions of grooves for shielded metal arc welding, gas metal arc
welding, and gas welding (except pressure gas welding). Note: Dimensions marked *
are exceptions that apply specifically to designs for gas metal arc welding.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

48. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 48
Code Welding Example
Recommended dimensions of grooves for gas tungsten arc welding processes
to obtain controlled and complete penetration. Note: for steel except as noted.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

49. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 49
NDT Magnetic Particle Testing
• One of most easily used nondestructive tests
• Used to inspect plate edges before welding for
surface imperfections
• Tests welds for surface cracks, incomplete
fusion, porosity, undercut, incomplete root
penetration, and slag inclusions
• Method limited to only magnetic materials
• Often referred to as Magnaflux® method
– Name of particular brand of testing equipment

50. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 50
NDT Magnetic Particle Testing
• Detects presence of internal and surface
cracks too fine to be seen by naked eye
– Depth of 1/4" to 3/8" below surface of weld
• Part prepared must be smooth, clean, dry and
free from oil, water, and excess slag
– Wire brushing and sandblasting
• Part magnetized by using electric current
• Magnetized surface covered with thin layer of
magnetic powder
– Another method uses fluorescent powder that
glows in black light

51. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 51
NDT Magnetic Particle Testing
• Layer of powder can be blown off surface
when no defects
– Defect shows because powder held to surface at
defect – “flux leakage”
• Magnetic field in workpiece sets up north pole at one
end of defect and south pool at other
• Cracks must be at angle to magnetic lines of
force in order to show
– Transverse (crosswise) crack would not show
because lines of force would be parallel with crack

52. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 52
Circular Magnetization
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

53. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 53
Magnetic Particle Testing
Units
Magnaflux Corp.
Portable magnetic particle testing
unit can be used in shop and field.
Shown here checking critical welds
during construction of a Detroit
bank building. Note use of
magnetic powder as unit applied.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

54. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 54
Example of Circular Magnetism
Circular magnetism is
when current passed
through workpiece, the
magnetic lines of force are
at right angles to current,
and discontinuities that
are angled against lines
of force will create flux
leakage needed to
produce magnetic poles
on the surface.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

55. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 55
Longitudinal Magnetism
Magnetic field is produced
with a coil, the lines of
force are parallel and
longitudinal. A
longitudinal crack will
not show, but a crack
angles against the lines
of force is indicated.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

56. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 56
NDT Magnetic Particle Testing
• Direct magnetization may also be used
with alternating current
– Limited to detection of surface discontinuities
only
• Indirect magnetization method
– Uses electrically supplied coil wrapped around
soft iron core to produce electromagnet

57. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 57
Direct Magnetization Using
D.C. Prods
American Welding Society, AWS B1.10
Guide for Nondestructive
Examination of Welds, Fig. 14, p. 15.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

58. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 58
Indirect Magnetization Using
a Yoke
American Welding Society, AWS B1.10 Guide for Nondestructive
Examination of Welds, Fig. 14, p. 15.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

59. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 59
Radiographic Inspection
• Nondestructive test method that shows
presence and type of microscopic defects
in interior of welds
• Utilizes either X-ray or gamma ray
– Source of X-rays is X-ray tube
– Gamma rays have shorter wavelengths and
produced by atomic disintegration of radium or
commercial radioisotopes
• Can penetrate deep, but exposure time longer than
X-rays

60. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 60
Radiographic Inspection
• Radiographs
– Film produced by X-rays or gamma rays
– Can establish presence of variety of defects and
record their size, shape, and relative location
• Size of X-ray equipment rated on basis of its
electric energy
– Voltage controls wavelength and penetrating
power
• Gamma rays come from radioisotopes that are
constantly emitting radiation – caution

61. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 61
Radiographic Testing
• Photograph taken of internal condition of weld
metal
– Photographic film placed on side opposite source
of radiation
– Distance between film and surface of workpiece
not greater than 1 inch
– Rays penetrate metal and produce image on film
• Different materials absorb radiation at different rates
• Slag absorbs less radiation than steel and permits
more radiation to reach film – thus slag shows up
darker

62. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 62
Typical Arrangement of Radiation
Source and Film in Weld Radiography
American
Welding
Society,
AWS
Bi.10
Guide
for
Nondestructive
Examination
of
Welds,
Fig.
14,
p.
15.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

63. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 63
Orientation of Discontinuities With
Radiographic Inspection
American Welding Society American Welding Society
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

64. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 64
Weld Discontinuities as Indicated
on Radiographic Film
Porosity as indicated by the dark
areas in lighter denser weld metal
Slag inclusion indicated by darker
less dense areas
Transverse cracks
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

65. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 65
Weld Discontinuities as Indicated
on Radiographic Film
Incomplete fusion, less dense area
along edge of weld
Incomplete penetration in root pass
Undercut as shown by less dense
areas along toe of cap pass
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66. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 66
Penetrant Inspection
• Nondestructive method for locating defects
open to surface; cannot detect interior defects
• Red dye penetrant method
– Surface must be clean
– Sprayed with dye penetrant which penetrates into
cracks and other irregularities
– Excess wiped clean with solvent
– Part sprayed with highly volatile liquid that
contains fine white powder (developer)
– Evaporation of liquid leaves dry white powder that
draws out red dye so defects marked clearly

67. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 67
Spotcheck®
• Dye penetrant test for defects open to surface
• Relies on penetration of defect by dye,
removal of excess dye, and development of
indication
• Highly sensitive process
• Small cracks show up against white developer
background
• Locates cracks, pores, leaks, and seams
invisible to unaided eye (shows in red)
• Used on almost all materials

68. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 68
Spotcheck® Advantages
• Complete portability for critical inspection
at remote shop or field locations
• Fast inspection of small, critical sections
suspected of being defective
• Ease of application and dependable
interpretation of results
• Low initial investment and low per part
cost in moderate volume uses

69. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 69
Spotcheck® Visible Penetrant
Magnaflux Corp.
Magnaflux Corp.
Spotcheck® visible
penetrant kit which
includes penetrant,
developer, and cleaner
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Applying Spotcheck®

70. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 70
Fluorescent Penetrant
• Technique similar to that used
in dye method
• Treated metal surface examined
under ultraviolet or black light in
semidarkness
– Florescent penetrant inspection
• Sharp contrast between
fluorescent material and base
background indicates cracks or
other defects in metal
• Useful for leak detection in
lined or clad vessels
Magnaflux Corp.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

71. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 71
Ultrasonic Inspection
• Nondestructive test method
• Rapid and has ability to probe deeply
without damaging weldment (200 inches)
• Able to supply precise information without
elaborate test setups
– Can detect, locate, and measure both surface
and subsurface defects in weld and base metal
• Needs experienced operator

72. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 72
Ultrasonic Inspection
• Done by means of electrically timed wave similar
to sound wave but higher pitch and frequency
• Ultrasonic – frequencies above human hearing
• Waves passed through material being tested and
reflected back by any density change
• Three basic types of waves
– Shear (angle) beams, longitudinal (straight) beams for
surface and subsurface flaws, and surface waves for
surface breaks and cracks
• Reflected signals appear on screen as vertical
reflections of horizontal baseline

73. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 73
Ultrasonic Inspection
• Transducer
– Search unit containing piezoelectric device that converts
electric energy into mechanical energy (sound) and then
converts sound back to electric
– Signal displayed on CRT or LCD
• Coupled to part to be inspected
– Two reference pips appear on screen, first pip echo
from surface called main bang; second pip echo from
bottom
– Distance between pips calibrated
– When defect picked up by search unit, produces third
pip
– Distance between pips and relative height indicate
location and severity of discontinuity

74. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 74
Ultrasonic Inspection
Agfa Corporation
Portable ultrasonic weld flaw
detector with built-in
trigonometric flaw location
calculations with curvature
correction and AWS
D1.1 weld rating calculation.
It has a 480-inch measurement
range in steel, 0.25 to 25-megahertz
frequency capability. The SmartView feature
displays the most relevant shot for critical scanning.
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75. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 75
Transducer Example
A CJP weld on a V-groove butt joint being
inspected with an angle transducer
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76. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 76
Ultrasonic Inspection
Short pulses
appear as pips
and register on
the ultrasonic
testing screen.
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77. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 77
Ultrasonic Testing
Nooter Corp.
Ultrasonic testing bond
of copper liner to base
metal of copper-clad
reactor. The welds were
X-rayed with gamma
rays, and chemical
analysis was made of
weld deposit.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

78. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 78
Ultrasonic Testing
Magnaflux Corp.
Using portable
ultrasonic instrument to
check a structural weld on
the seventy-sixth floor of
the John Hancock Building
in Chicago.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

79. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 79
Radiographic Inspection
This video clip shows the RT inspection of a weld.

80. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 80
Eddy Current Testing
• Makes use of electromagnetic energy to detect
defects in material
• When coil has been energized with alternating
current at high frequency brought close to
conductive material, will produce eddy currents
– Secondary currents induced in conductor
– Caused by variation in magnetic field
• Search coil used and connected to meters,
recorders which pick up signals from weldment
– Defect in material distorts magnetic field and indicated
– Size shown by amount of change

81. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 81
Eddy Current Testing
• Suitable for both ferrous and nonferrous
materials
• Used extensively in testing welded tubing,
pipe, and rails
• Can determine physical characteristics of
material, wall thickness in tubing and thickness
of various coatings
• Only good up to 3/16 inch thickness and
calibration blocks required for all types of
welds
– Two areas that limit its use

82. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 82
Eddy Current Testing
Forster
Instruments
Eddy current control and rotating probe.
The control is compact and portable.
This single-channel test instrument
incorporates all the features required
for automatic testing.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

83. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 83
Eddy Current Testing
Core
American Welding society, AWS B1.10 Guide for Nondestructive
Examination of Welds, Fig. 28, p.25.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

84. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 84
Leak Tests
• Made by means of pneumatic or hydraulic
pressure
• Load applied that is equal to or greater than
expected in service
• Usually used to test pressure vessels and
pipelines
• If used as destructive method, pressure applied
until unit bursts
• Water usually used to test for leaks
– Hydrogen, oil, and helium also used
– Weld seam painted with liquid soap when testing with
air and bubbles appear where leaks

85. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 85
Hardness Tests
• Important to know harness of weld deposit
if weld going to be machined or subject to
surface wear
• Number of nondestructive hardness tests
– Brinell
– Rockwell
– Vickers
– Knoop

86. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 86
Brinell Hardness Test
• Consists of impressing hardened steel ball into
metal to be tested at given pressure for
predetermined time
– Diameter of impression measured and indicates
Brinell number on chart
– Ball 10 ± 0.0025 millimeters forced into specimen
by hydraulic pressure of 3,000 kilograms for 15
sec.
• Brinell hardness number (BHN) can be related
to actual tensile strength of carbon steel
– Multiply DHN by 500

87. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 87
Rockwell Hardness Test
• Similar to Brinell system, but differs in that
readings obtained from dial
• Measures depth of residual penetration made
by small hardened steel ball or diamond cone
– Minor load of 10 kg applied, which seats
penetrator (ball or cone) in surface of speciment
– Then full load of 150 kg applied
– After major load removed, hardness number
indicated on dial gauge
• Numbers based on difference of penetration between
major and minor loads

88. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 88
Rockwell Hardness Test
• Two Rockwell scales
– C-scale
• Cone-shaped diamond penetrator used instead of
ball
• Applied at load of 150 kg
– B-scale
• Used for softer metals
• Penetrator is hardened steel ball 1/8" or 1/16" in
diameter applied at lesser load of 100 kg

89. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 89
Microhardness Testing
• Uses range of loads and diamond indenters to
make indentation
– Measured and converted to hardness value
• Two types of indenters
– Square base pyramid-shaped diamond (Vickers)
– Narrow rhombus shaped indenter (Knoop tester)
• Typically light loads
• Used to test metals, ceramics, and composites

90. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 90
Microhardness Testing:
Vickers Method
• Testing of very thin materials like foils
• Measuring surface of part
• Small parts or small areas
• Measuring individual microstructures
• Measuring depth of case hardening by
sectioning part and making series of
indentations to describe profile of change
in hardness

91. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 91
Microhardness Testing:
Knoop Method
• Closely spaced requirements
• Testing close to an edge due to the narrow
shape of the indentation
• More resolution due to the width of the
Knoop indentation
• Thinner materials because indentation is
less deep

92. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 92
Impact Hardness Tester
• Done with portable machine
– Easy to operate and extremely accurate
– Takes 1 second to perform
– Hardnesses displayed digitally
– Permits testing in any direction, automatically
adjusted for gravity
– Unit coverts electronically to Brinell, Rockwell
Ba and C, Shore, and Vickers scales
• Uses comparative method of evaluating
hardness

93. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 93
Impact Hardness Tester
• Equipment does not need to be zeroed or
adjusted
• Typical metals tested
– Cast steel, irons, tool steel, aluminum, yellow
metals, stainless steel
• Designed for use on all metallic materials
from 80 Brinell to about 68 Rockwell C
• Accuracy is in the ± 0.5%

94. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 94
Compact Portable Sonic
Hardness Tester
Micro Photonics, Inc.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

95. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 95
Destructive Testing
• Mechanical testing of weld samples to
determine strength and other properties
– Relatively inexpensive and highly reliable
• Usually performed on test specimens
taken from welded plate that duplicates
material and weld procedures used on job
• Certain general test procedures developed
by AWS that are standard for industry and
various code-making bodies

96. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 96
Groove Welds
• Reduced-section tension test
– Determines tensile strength, yield strength, and
ductility; used for procedure qualification
• Free-bend test
– Determines ductility; used for procedure
qualification
• Root-bend test
– Determines soundness; used widely for welder
qualification; also used for procedure
qualification

97. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 97
Groove Welds
• Face-bend test
– Determines soundness; used widely for welder
qualification; also used for procedure qualification
• Side-bend test
– Determines soundness; used widely for welder
qualification; also used for procedure qualification
• Nick-break test
– Determines soundness; at one time used widely
for welder qualification; used infrequently today

98. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 98
Fillet Welds
• Longitudinal and transverse shear tests
– Determines shear strength; used for procedure
qualification
• Fillet weld soundness test
– Determines soundness; used extensively for
welder qualification
• Fillet weld break test
– Determines soundness; used infrequently today
• Fillet weld fracture and macro test
– Determines soundness; ASME test for procedure
qualification and welder qualification

99. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 99
General Requirements
• All codes require essentially same qualifying
procedures for plate or pipe
• Each position of welding, type of joint, and
weld has designated number for identification
• Generally, face-, root-, and side-bend test
specimens required for groove welds in plate
or pipe
• T-joint break or macro-etch test specimens
required for fillet welds in plate
• Required number and type of test specimens
vary with thickness of material

100. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 100
General Requirements
• Under most welding codes, tests remain in
effect indefinitely unless:
– Welder does not work with welding process for
which he/she qualified for period of more than
6 months
• Requalification required only on 3/8" thick plate
– Reason to be dissatisfied with work of welder
• Immediate retest consists of two test welds of each
type failed (All specimens must pass)
• Complete retest if welder has had further training or
practice since last test

101. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
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Procedure Qualification Tests
• Conducted for purpose of determining
correctness of welding method
• Should cover:
– Filler metals
– Joint preparation
– Position of welding
– Welding process
– Base metal
specifications
– Techniques and
characteristics
– Current setting
– Electrode size
– Electrode manipulation
– Preheat and postheat

102. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 102
Procedure Qualification Tests
• Groove weld
– Specimens required given in Table 28-9 in text
• Fillet welds
– Longitudinal shear test
– Transverse shear test
– Bend and soundness test
– Two root-bend tests
• Table 28-10 covers requirement for fillet
well soundness test for WPS

103. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 103
Welder Qualification Tests
• Also referred to as performance qualification test
• Conducted for purpose of determining whether welder has
knowledge and skill to make sound welds and to follow and
apply procedure of welding for class of work
• General practice for code welding to qualify on groove weld
tests in 3G and 4G positions
– Time limits imposed by specific codes on how long a welder
remains qualified
• AWS D1.1 it is indefinitely
• If they are using the welding process and procedures continuously
• If six months transpire between use
• Or if the welders ability is being questioned they will have to take a
requalification test

104. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 104
Welder Qualification Tests
• Groove welds
– Table 28-12 covers various complete joint
penetration groove weld tests
• Based on various plate thicknesses
• Fillet welds
– Two different kinds of fillet weld specimens
• Figure 28-63, welds made in each position for
which welder is to be qualified; two root-bend tests
made
• Figure 28-65, welds subjected to fracture test and
etched

105. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 105
Preparation of Test Specimens
• Selecting and preparing plates
– Test plate and backup strip, if used, are
weldable, ductile low carbon steel
– Test designed so both plate and weld will bend
and stretch during test
• Welding plates
– First step proper electrode selection
– Important on first pass to get good penetration,
fusion, and sound weld metal on root beads
– No preheat or postheat treatment permissible
to pass test

106. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 106
Preparation of Test Specimens
• Finishing the specimen
– All grinding and machining marks must be
lengthwise on sample
– Surface should be smooth, with no low or
irregular spots
– Edges of specimen should have smooth 1/8"
radius
– Do not quench in water when done grinding
– After test specimens have been bent, outside
surface visually examined for surface
discontinuities

107. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
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Acceptable Test Specimens
• Surface shall contain no discontinuities
exceeding the following dimensions
– 1/8" measured in any direction on surface
– 1/8" as sum of all discontinuities exceeding 1/32"
but less than 1/8"
– 1/4" maximum corner crack, except when results
from visible slag inclusion or other fusion-types in
which case 1/8" maximum size applies
– If corner crack exceeds 1/4" and no evidence of
slag or fusion type discontinuities, then it shall be
discarded

108. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 108
Reduced-section Tension Test
• Purpose
– Determine tensile strength of weld metal
– Used only for procedure qualification tests
– Suitable for butt joints in plate or in pipe
• Usual size and shape of specimens
– Figures 28-69 through 28-71 in text

109. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 109
Reduced-section Tension Test
• Method of testing
– Subjecting specimen to longitudinal load great
enough to break it or pull it apart
– Before testing, least width and corresponding
thickness of reduced section measure in
inches
– Cross sectional area = width x thickness
– Tensile strength in pounds per square inch
obtained by dividing maximum load by cross-
sectional area

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WELDING:
Principles
and
Practices,
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Reduced-section Tension Test
• Usual test results required
– Specimen shall have tensile strength equal or
greater than
– Minimum specified tensile strength of base
material
– Lower of minimum specified tensile strengths
of dissimilar materials
– Specified tensile strength of weld metal if weld
metal is of lower strength than base metal
– 5% below specified minimum tensile strength
of base metal if specimen breaks in base metal
outside of weld

111. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 111
Root-, Face-, and Side-bend
Soundness Test
• Purpose
– Revealing incomplete soundness, penetration,
and fusion in weld metal
– Procedure and welder qualification tests
applied to groove welds in both plate and pipe
– Face-bend test checks quality of fusion to side
walls and face of weld joint, porosity, slag
inclusion, porosity, and measures ductility
– Root-bend test checks penetration and fusion
throughout root of joint
– Side-bend test checks for soundness and
fusion

112. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 112
Root-, Face-, and Side-bend
Soundness Test
• Usual size and shape of specimens
– Refer to Figures 28-73 through 28-75 in text
• Method of testing
– Each specimen bent in jig having the contour
– Manual, mechanical, electrical, or hydraulic
means may be used for moving male member
in relation to female member
– Specimen place on female member of jig with
weld at midspan

113. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 113
Root-, Face-, and Side-bend
Soundness Test
• Method of testing, cont.
– Face-bend specimens placed with face
directed toward gap
– Root-bend specimens placed with root directed
toward gap
– Side-bend specimens placed with side showing
greater discontinuity, if any, toward gap
– Two members of jig force together until
curvature of specimen such that 1/32" diameter
wire cannot be passed between curved portion
of male member and specimen
– Specimen then removed from jig

114. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 114
Root-, Face-, and Side-bend
Soundness Test
• Usual test results required
– Convex surface of specimen visually examined
– To be acceptable, no discontinuities exceeding:
• 1/8 inch in any direction on surface
• 3/8 inch as sum of all discontinuities exceeding 1/32 inch
but less than 1/8 inch
• 1/4-inch maximum corner crack, except when corner
crack results from visible slag inclusion or other fusion
type discontinuities, in which case 1/8-inch maximum size
shall apply
• If corner crack exceeds 1/4 inch and no evidence of slag
or fusion type discontinuities, then it is discarded

115. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 115
Nick-break Test
• Purpose
– Determining soundness of weld
• Usual size and shape of specimens
– Refer to Figures 28-81 and 28-82 in text
• Method of testing
– Weld reinforcement not removed from
specimen
– Specimen notched in sides by saw, supported
and struck with quick, sharp blows by hammer
or heavy weight

116. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 116
Nick-break Test
• Usual test results required
– Fractured surface does not have any
discontinuities exceeding these limits:
• Greatest dimension of porosity shall not exceed
1/16 inch
• Combined area of all porosity not exceed 2% of
exposed surface area
• Slag inclusions hall not be more than 1/32" in depth
and not more than 1/8" or one-half nominal
thickness in length
• No incomplete fusion allowed
• At least 1/2-inch separation between adjacent
discontinuities

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WELDING:
Principles
and
Practices,
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Longitudinal and Transverse
Shear Tests
• Purpose
– Determining shearing strength of fillet welds
– Used for procedure qualifications
• Usual size and shape of specimens
– Refer to Figures 28-80 through 28-82 for
standard specifications
– Figures 28-86 and 28-87 show prepared
longitudinal weld specimens

118. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 118
Longitudinal and Transverse Shear
Tests: Method of Testing
• Specimen ruptured by pulling in tensile testing
machine and maximum load in pounds
determined
• Transverse welds
– Before pulling, width of specimen measured in inches
and size of fillet weld recorded
– Pounds per linear inch obtained by dividing maximum
force by twice width of specimen
– Shearing strength of weld in pounds per square inch
obtained by dividing shearing strength (p.s.i.) by
average theoretical throat dimension
– Theoretical throat dimension = fillet weld times 0.707

119. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
4e 119
Longitudinal and Transverse Shear
Tests: Method of Testing
• Longitudinal welds
– Before pulling, length of each weld measure in inches
– Shearing strength of welds in pounds per linear inch
obtained by dividing maximum force by sum of lengths
of welds that ruptured
• Usual test results required
– Longitudinal shear: shearing strength (p.s.i.) cannot
be less than 2/3 minimum specified tensile range of
base material
– Transverse shear: shearing strength of welds in
pounds per square inch cannot be less than 7/8th of
minimum specified tensile range of base material

120. © 2012The McGraw-Hill Companies, Inc. All rights reserved.
WELDING:
Principles
and
Practices,
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Fillet-weld Break Test
• Purpose
– Determining soundness of fillet weld
– Several different tests, one by AWS
• Method of testing
– Fillet welding one flat plate or bar at right
angles to another in form of T-joint
– Specimen removed (6") with one start or stop
– Specimen fractured by application of pressure
from press, testing machine, or hammer
– Fractured at root, and fractured material
examined

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WELDING:
Principles
and
Practices,
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Fillet-weld Break Test
• Usual test results required (AWS)
– Weld must fracture through throat of weld
– Visual examination shall show
• Uniform appearance
• Uniform weld size, not varying over 1/8 inch
• No overlap
• No cracks
• No undercut greater than 0.010 inch
• No visible surface porosity

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WELDING:
Principles
and
Practices,
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Etching
• Reveals penetration and soundness of weld cross
section
• Objectives of test:
– Determine soundness of weld
– Make visible boundaries between weld metal and base
metal and between layers of weld metal
– Determine location and depth of penetration of weld
– Determine location and number of weld passes
– To examine metallurgical structure of heat-affected zone
• Inspected with polarizing microscope or
photographed with metallograph

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WELDING:
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and
Practices,
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Etching
• Transverse section cut from welded joint
• Face of weld and base material filed to
smooth surface and polished with fine
emery cloth
• Surface exposed to one of the following:
– Iodine and potassium iodide
– Nitric acid
– Hydrochloric acid
– Ammonium persulphate

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WELDING:
Principles
and
Practices,
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Etching
• Macroetch test (less than 10x magnification)
– Visual test
• Fillet weld macroetch test shall have:
– No cracks
– No incomplete fusion
– Weld profiles that blend smoothly into base metal
– No convexity or concavity exceeding 1/16"
– No undercut exceeding 0.010"
– No porosity or inclusions greater than 1/32"
– No acceptable porosity or inclusions exceeding
1/4"

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WELDING:
Principles
and
Practices,
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Objectives of Etching
• To determine soundness of weld
• To make visible boundaries between weld
metal and base metal and between layers of
weld metal
• To determine location and depth of fusion and
penetration of weld
• To determine location and number of weld
passes
• To examine metallurgical structure of heat-
affected zone

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WELDING:
Principles
and
Practices,
4e 126
Impact Testing
• Determines impact strength of welds and base
metal in welded products
• Impact strength is ability of metal to withstand
sharp, high velocity blow
– Compares toughness of weld metal with base
metal
• Two standard methods of testing
– Izod and Charpy tests
• Specimen broken by single blow
• Impact strength measured in foot-pounds

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WELDING:
Principles
and
Practices,
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Impact Testing
• Both types of tests make in impact-testing
machine
• Difference between tests mainly the position of
the notch in the test specimen
• Amount of energy in falling pendulum known
• Distance through which pendulum swings after
breaking specimen indicates how much of total
energy used in breaking it
– Shorter the distance, the higher reading on scale

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WELDING:
Principles
and
Practices,
4e 128
Impact Testing
The Lincoln Co.
The Lincoln Co.
Typical impact test specimens and methods of holding and
applying the test load. The V-notch specimens shown have
an groove angle of 45º and a bottom radius of 0.010" in
the notch.
Izod Test Charpy Test
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WELDING:
Principles
and
Practices,
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Fatigue Testing
• Purpose is to find out how well weld can resist
repetitive stress as compared to base metal
• Improperly made welds that contain defects
like porosity, slag inclusions, and cracks don't
blend smoothly into base metal
• Two principal methods of testing
– Specimen bent back and forth in regular fatigue-
testing machine
– Specimen rotated under load in testing machine

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WELDING:
Principles
and
Practices,
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Corrosion Testing
• Weld metal and base metal subjected to
corrosive conditions similar to
environmental conditions weldment will be
exposed
– Materials compared for resistance to corrosion
– Defect shows as difference in rate of corrosion
when compared to base metal
• Weld metal must be equal to or better than
base material in corrosion resistance

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WELDING:
Principles
and
Practices,
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Specific Gravity
• Used to make sure no fine porosity exists
• Performed in laboratory
• Test specimen
– Cylinder of all-weld metal 5/8" in diameter and
2" long taken from weld bead
• Specific gravity obtained by dividing weight
in grams by volume in cubic centimeters
• High quality weld will have specific gravity
of 7.80 grams per cubic centimeter

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WELDING:
Principles
and
Practices,
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Visual Inspection
• Most widely used of all inspection methods
• Quick and does not require expensive
equipment
– Good magnifying glass (10x) recommended
• Required before more expensive NDE
methods applied
• Should be employed by welder, welding
inspector, and supervisor from beginning
to end of welding job

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WELDING:
Principles
and
Practices,
4e 133
Principal Defects
• Incomplete penetration
• Incomplete fusion
• Undercutting
• Inclusions
• Porosity
• Cracking
• Brittle welds
• Dimensional defects

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WELDING:
Principles
and
Practices,
4e 134
Incomplete Penetration
• Failure of filler and base metal to fuse
together at root of joint
• Root-face sections of welding
groove may fail to reach melting
temperature for entire depth or
not reach root of fillet joint
– Leaves void caused by bridging
of weld metal from one plate
to another
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WELDING:
Principles
and
Practices,
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Incomplete Penetration
• Will cause weld failure if weld subjected to
tension or bending stresses
• When welded from one side, following
conditions likely to cause incomplete
penetration
– Root-face dimension too big even though root
opening adequate
– Root opening too small
– Groove angle of V-groove too small

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WELDING:
Principles
and
Practices,
4e 136
Incomplete Penetration
• Will result from following error in technique
even if joint design adequate
– Electrode too large
– Rate of travel too high
– Welding current too low

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WELDING:
Principles
and
Practices,
4e 137
Incomplete Fusion
• Failure of welding process to fuse together
layer of weld metal or weld metal and base
metal
• Overlap
– Weld metal just rolls over plate surfaces
• May occur at any point in welding groove
• Very often good fusion at root and plate
but toe of weld does not fuse (heat
conduction and poor technique)

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WELDING:
Principles
and
Practices,
4e 138
Incomplete Fusion
• Caused by:
– Failure to raise temperature of base metal or
previously deposited weld metal to melting
point
• Electrode too small
• Rate of travel too fast
• Arc length too close
• Welding current too low
– Improper fluxing which fails to dissolve oxide
and other foreign material from surfaces which
deposited metal must fuse

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WELDING:
Principles
and
Practices,
4e 139
Avoiding Incomplete Fusion
• Making sure that surfaces to be welded
are free of foreign material
• Selecting proper type and size of
electrodes
• Selecting correct current adjustment wire-
feed speed, and voltage
• Using good welding technique

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WELDING:
Principles
and
Practices,
4e 140
Undercutting
• Burning away of base metal at toe of weld
– On multilayer, occur at juncture of layer with wall
of groove
• Caused by:
– Poor technique
– Type of electrode used
– Current adjustment too high
– Arc length too long
– Failure to fill up crater completely
• Very serious defect
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WELDING:
Principles
and
Practices,
4e 141
Undercutting
• To prevent serious effect, correct before
depositing next bead
• Rounded chipping tool used to remove sharp
recess
• If at surface of joint, should not be permitted
– Reduces strength of joint
• If weld part of primary member and transverse to
tensile stress, undercut can be no more than
0.010" in depth
– Special undercut gauge made for this precise
measurement
• Visible inspection used

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WELDING:
Principles
and
Practices,
4e 142
Inclusions
• Entrapped foreign solid materials in weld
– Slag, flux, tungsten, or oxides
– Usually elongated or globular in shape
• Most can be prevented by:
– Preparing groove and clean properly before
each bead deposited
– Taking care to avoid leaving any contours that
will be difficult to penetrate fully with arc
– Making sure all slag has been cleaned from
surface of previous bead

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WELDING:
Principles
and
Practices,
4e 143
Porosity
• Presence of pockets that do not contain any
solid material
• Gases forming in voids derived from:
– Gas released by cooling weld metal
– Gases formed by chemical reactions in weld
• Excessive porosity can effect the mechanical
properties of joint
• Porosity may be scattered uniformly, isolated
in small groups or concentrated at root

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WELDING:
Principles
and
Practices,
4e 144
Porosity
• Best prevented by avoiding:
– Overheating and underheating of weld metal
– Excess moisture in covered electrode
– Contaminated base metal or consumables
– Too high current setting
– Too long an arc
• Code specifies maximum size acceptable

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WELDING:
Principles
and
Practices,
4e 145
Cracking
• Linear ruptures of metal under stress
• Occur in weld metal, in plate next to weld
or in heat-affected zone
• Three major classes of cracking
– Hot cracking
– Cold cracking
– Microfissuring

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WELDING:
Principles
and
Practices,
4e 146
Hot Cracking
• Occurs at elevated temperatures during
cooling shortly after weld deposited and
started to solidify
• Stress must be present to induce cracking
• Slight stress causes very small cracks
detected only with some of nondestructive
testing techniques such as radiographic and
liquid penetrant inspection
• Most welding cracks hot cracks

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WELDING:
Principles
and
Practices,
4e 147
Cold Cracking
• Cracking at or near room temperature
• May occur hours or days after cooling
• Usually start in base metal in heat-affected
zone
• May appear as underbead cracks parallel
to weld or as toe cracks at edge of weld
• Occurs more often in steels than other
metals

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WELDING:
Principles
and
Practices,
4e 148
Microfissures (Microcracks)
• May be either hot or cold cracks
• Too small to be seen with naked eye
• Not detectable at magnifications below 10
power
• Usually do not reduce service life of
fabrication

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WELDING:
Principles
and
Practices,
4e 149
Weld Metal Cracking
• Three different types
– Transverse cracks
• Run across face of weld and may extend into base
metal
• Usually caused by excessive restraint during welding
– Longitudinal cracks
• Usually confined to center of weld deposit
• If not eliminated, crack will progress through entire
weld
– Crater cracks
• Usually proceed to edge of crater and may be starting
point for longitudinal crack

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WELDING:
Principles
and
Practices,
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Longitudinal Cracking
• Corrected by
– Increasing thickness of the root pass deposit
– Controlling heat input
– Decreasing speed of travel to allow more weld
metal to build up
– Correcting electrode manipulation
– Preheating and postheating
• May be continuation of crater cracks or
cracks in first layer of welding

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WELDING:
Principles
and
Practices,
4e 151
Cracks in Welded Joints
Examples of
crater cracks
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WELDING:
Principles
and
Practices,
4e 152
Cracks in Welded Joints
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WELDING:
Principles
and
Practices,
4e 153
Cracks in Welded Joints
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WELDING:
Principles
and
Practices,
4e 154
Base Metal Cracking
• Usually occur along edges of weld and through
heat-affected zone into base metal
• Possibility of cracking increases when working
with hardenable materials
• Underbead crack (mainly in steel)
– Base metal crack usually associated with hydrogen
• Toe cracks caused by hot cracking in or near
fusion line
• Arc strikes (accidental touching of electrode to
work) may cause small cracks
• Can also be started as result of undercutting

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WELDING:
Principles
and
Practices,
4e 155
Base Metal Cracking
• Root cracks often produce cracking in plate on
side opposite weld
• Nonfused area may crake if area subject to
tensile strength
• Improper design with little regard for
expansion and contraction contributes to
cracking
• Care must be taken in type of steel selected
and electrode chosen for welding

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WELDING:
Principles
and
Practices,
4e 156
Brittle Welds
• Has poor elongation, very low yield point,
very poor ductility, and poor resistance to
stress and strain
• Highly subject to failure and may fail without
warning any time during life of weldment
• Principle cause is use of excessive heat
which burns metal
• Avoid by using multilayer welds and careful
selection of material and electrode

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WELDING:
Principles
and
Practices,
4e 157
Dimensional Defects
• Caused by improper welding procedure
and/or technique and include:
– Longitudinal contraction
– Transverse contraction
– Warping
– Angular distortion
• Controls that help prevent
– Welding jigs, proper welding sequences,
correct welding procedure, suitable joint
design, and preheat and postheat

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WELDING:
Principles
and
Practices,
4e 158
Weld Gauges
• Tools used to make sure completed weld
within limits specified by engineering design
and weld procedure
• Two designs: concave and convex
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WELDING:
Principles
and
Practices,
4e 159
Method of Using Weld Gauge
Size of
Convex Fillet
Maximum
Convexity
Two Examples
General Electric Co.
General Electric Co.
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WELDING:
Principles
and
Practices,
4e 160
Weld Gauge
Method of using fillet weld
gauge to determine size
of a convex fillet weld
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WELDING:
Principles
and
Practices,
4e 161
Laser Scanners
• New stage in weld inspection handheld
devices
• Can be used for preweld inspection to
determine if joint design meets specification
• Can select type of inspection, view
measurement and results on bright color
display
• Data stored in memory or downloaded to
computer

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WELDING:
Principles
and
Practices,
4e 162
Summary
• Welding demands constant visual examination
during entire operation
– Many variables to adjust continuously
– Special attention given to root pass
• Tables 28-5 and 28-6 summarize various weld
and base metal defects that may be
encountered
• Table 28-7 gives the recommended inspection
methods for evaluating fillet and butt joints

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WELDING:
Principles
and
Practices,
4e 163
Summary
• Visual inspection most convenient method
• Radiographic inspection permits looking into
weld for defects that fall within sensitivity
range of the process
• Magnetic particle inspection outstanding for
detecting surface cracks and used to
advantage on heavy weldments and
assemblies
• Dye penetrant easy to use for detecting
surface cracks

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WELDING:
Principles
and
Practices,
4e 164
Summary
• Ultrasonic inspection excellent for detecting
subsurface discontinuities, but requires expert
interpretation
• Hydrostatic testing determines tightness of welds
in fabricated vessels
• Hardness tests indicate approximate tensile
strengths of metals and show whether or not
base metal and weld metal strengths matched
• Destructive testing gives absolute measure of
strength of sample tested