Detailed Presentation on Radiography Testing. It is prepared on the lines of ASNT Level II pattern. A V Abhishek abhishek.agyarapu@gmail.com

1. Presentation
on
Radiography Testing
By
Abhishek A V
abhishek.agyarapu@gmail.com

2. Outline
• Application, Pros & Cons
• Principle/Source Generation
• Exposing Time, Film & its Characteristics
• Penetrameters / IQI
• Type of Technique
• Defects/Identification
• Film Interpretation
• Acceptance Criteria
• Report Format
• Safety Precaution
RT- Radiography Testing

3. Advantages & Disadvantages
S.No Advantages Disadvantages
1 Can be used to inspect virtually all
materials.
Extensive operator training and skill
required.
2 Detects surface and subsurface
defects.
Depth of Discontinuity not Indicated
3 Permanent Test Report can be
Obtained
Access to both sides of the structure is
usually required.
4 Ability to inspect complex shapes,
Hidden areas and multi-layered
structures without disassembly.
Orientation of the radiation beam to non-
volumetric defects is critical.
5 Minimum part preparation is
required.
Relatively expensive equipment and
investment is required.
6 Technique standardized and
Reference standards available
Possible radiation hazard for personnel.
Application:
o Pipe work
o Pressure vessels and boilers
o Structural steel works
o Ship building
Note:
Testing can be carried out upto 200 mm

4. Introduction to Radiography
o The radiation are of higher energy (shorter
wavelength) version of the electromagnetic waves
o Source – X ray/ Gamma ray
o X-rays are produced by an x-ray generator
o Gamma radiation is the product of radioactive
atoms.
o X-rays and gamma rays can be characterized by
frequency, wavelength, and velocity.
High Electrical Potential
Electrons
-+
X-ray Generator
or Radioactive
Source Creates
Radiation
Exposure Recording Device
Radiation
Penetrate
the Sample

5. Principle – Differential Absorption
Top view of developed film
X-ray film
= more exposure
= less exposure
The film darkness (density) will vary
with the amount of radiation reaching
the film through the test object.
• Different parts of object will absorb the radiation differently depending
on thickness, density and the atomic no of the object
Thinner portion will absorb less radiation and
transmit more radiation on to film and hence
more black will be on film and vice-versa

6. Generation of Sources
Source Depends on Type of Material
Material Thickness
Location of Testing
Thickness , Energy , Penetration, Radiation Hazards
Electrically Generated form
X Ray Tube/Tube Heads
Requires Power Supply
Radiation Controllable
 Less Hazardous
Generated by decay of unstable atoms
Source - Artificial Isotopes Iridium, Cobalt
Iridium – Max Penetration -75 mm in steel
Cobalt–Max Penetration -200 mm in Steel
 Applicable for Onsite
No Power Required
Radiation is Non – Controllable
 Isotopes can be replaced & periodic Inspection
More Hazardous

7. Penetration Level w.r.t Source w.r.t Exposure
Steel Aluminum
Medical Diagnostics – 50 KV
X rays are measured in KV
Gamma measured Rays in MeV

8. Exposing Time
Depends on
o Material of the Object – Steel/Al/Cu
o Material thickness
o Type of Film – Slow/Medium/Fast
o Film Density
o Source to Film Distance – SFD
o Source – X Ray/Gamma Ray – Intensity/Energy
How to find Exposure Time:
o Exposure Chart – X Ray Only
o Exposure Scale – Gamma Ray – Onsite Application
o Exposure Formulae - Gamma Ray
Exposure Scale
Exposure Time Formulae
= Film Factor x 2 N x (SFD)2 x 60
RHM x S x (100)2
RHM = Roentgen Hour Meter
SFD = Source to Film Distance
N = Thickness /Half Value Thickness

9. Exposure Equivalent Chart Exposure Chart
Exposure Time for X – Ray
Less straight forward because the wavelength and intensity are variable
Exposure for X Rays determined by
o By Exposure Charts
o By Reference to previous exposure records
o By Trial and error test shots
o By combination of above

10. Geometric Principle of Shadow
Sharpness of the shadow dividing line b/w areas of different density
Controlled by Controlled by
Note
Object Should be kept as close as touch/near to Film
Object to be kept parallel to film axis
Central ray of beam (Focal Spot) should be perpendicular to film axis

11. Geometric Unsharpness (Ug) – Width b/w Umbra & Penumbra
Sharp Image – Umbra
Unsharp Image – Penumbra
To minimize penumbra
o Source size as small as possible
o SOD/FFD as large as possible
o OFD as small as possible
Ug= f x t /SOD
f – focal point
t - thickness (for solid object)
SOD – Source to Object Distance
Object Thickness / Ug
Below (50mm) = max. Ug. (0.50mm)
(50 - 75mm) = max. Ug. (0.75mm)
(75 - 100mm) = max. Ug. (1.00mm)
Above (100mm) = Ug (1.75mm)

12. Film Characteristics
Film Density - Degree of Blackening
Low Film/High Film Density
Measure by Densitometer
For X Rays :1.8 – 4; For Gamma rays : 2-4
Film Speed Film which gives exposing time
Exposing Time less – Fast Film
Exposing time medium – Medium Film
Exposing time Fast – Slow Film
Film Sensitivity Ability to detect smallest flaw
Film ResolutionSeparation of close lying Defects
Film Graininess Small Size- Slow Film – Less Graininess
Big Size- Fast Film – More Graininess
Film Contrast Degree of Shining
More Shining – High Film Contrast
Less Shining – Low Film Contrast
Film Characteristics Curve / Sensitometric Curve/Hunter & Driffield Curve
Density is plotted against log of exposure
Film type Material Thickness
Class I T < 0.5”
Class II T >0.5” to T < 1.0”
Class III T >1”

13. Film Characteristics Curve / Sensitometric /Hunter & Driffield Curve
1. Position of Curve on Exposure axis gives information on film speed
2. Position of Straight line portion of curve against density axis gives density range with which
the film is at its optimal
3. Gradient of Curve gives information on films contrast
Films are classified into Type 1, Type II and Type III

14. Intensifying Screens
Film is sandwiched between intensifying screens
Three types a) Lead Screens
b) Fluorescent Screens
c) Flurometallic screens
Lead Intensifying Screens
o Front Screen shortens exposure time and improves quality by filtering backscatter
o Back screens act as filter only
o Screen thickness 0.02 mm to 0.15 mm
Fluorescent Screens
o Intensification twice of Lead Screen
o Cost effective
Flurometallic screens
o Front screen act as filter and intensifier
o Intensifying Action achieved by emitting light radiation and particulate radiation electrons

15. Dev.
Stop
Bath
Fix
Wash
Running Water
Dryer
Film Processing
o Developer - converts latent image into manifest image (10-12 Min- Agitate)
o Stop Bath – Removes Excess Developer (10-15 Sec)
o Fixer -Clean the film of unexposed, undeveloped AgBr crystals, promotes archival quality (5 Min)
o Wash – rid the film of residual chemicals
o Wetting the film to swell the emulsion
Note :For manual processing a floating thermometer, a timer and the time -temperature chart are
essential.
Types of Processing
1. Manual
2. Semi Automatic
3. Automatic

16. Penetrameters /Image Quality Indication
o To achieve a radiographic image with highest quality
o It provide a means of visually informing the film interpreter of the contrast
sensitivity and definition of the radiograph
1% Sensitivity –Aerospace Application
2 % Sensitivity –Industrial Application
Sensitivity–Ability to detect smallest flaw
Types of IQI Commonly Used
1. Wire Type
2. Step Hole Type
3. Plaque Hole Type (Step – Hole Type)
o IQI Thickness = 2 % (Object Thickness)
o Unit of IQI Thickness = Thou (40 Thou =1 mm)
Suppose, Object – 8 mm Thickness
= 2 % (8) = 0.16 mm
So, the minimum size of the discontinuity
that should be visible in the radiography film
is of 0.16mm

17. Placement of Penetrameters /IQI
o To be placed at worst location/Extreme edge of radiographic film
o To be placed at Source Side, in case use Film Side ~ DWSI/DWDI (Indicate Letter F)
o For Weld, Wire Type IQI to be kept across the weld
o For Weld, Plate & Hole, Step Wedge , parallel to weld 3mm away from weld edge
o When there is no accessibility , Block/shim to be used & IQI to be placed on it.
o Density of radiograph varies from location of IQI by more than -15%
to 30 % then another IQI is required
o For Circumferential weld in SWSI-Panaromic technique,
3 IQI’s at 120o apart, 4 IQI at 90o apart
o Backing rings or strips and root penetration are not to be considered as part of the weld or
reinforcement thickness in selection of the IQI.
o The material of the IQI shall be of similar radiographic density to that of the material under
examination, i.e. use steel for steel, aluminium for aluminium, etc.,

18. Wire Type Penetrameters /IQI
o In Wire Type IQI, Four standards - ATSM, ISO, DIN, EN
o ASTM has four Sets- A, B,C,D & its wire identification
o All 6 wires are equally spaced and same height
o 4 alternative Sets for ASTM Standard available – Selected by End User
Alternative Sets- ASTM
Selection of Wire Type IQI as per ASTM E 747-97

19. Plate Hole/Plaque Penetrameters /IQI
Selection of Plate Hole IQI Can be differentiated by Notch
XX- Thickness of IQI on thou
A - 4 T Hole
B – 1 T Hole
C – 2 T Hole
Different Sensitivity Level
2-2T IQI normally used
 2- % of thickness of Object
2T- Image to be seen on Film
1-1T 2-2T 4-1T
1-2T 2-2T 4-2T
1-4T 2-4T 4-4T

20. Back Scatter Radiation
o A lead symbol “B” with minimum dimensions of 1/2 inch in height and 1/16
inch in thickness, shall be attached to the back of film holder to determine if
backscatter radiation is exposing the film.
o If a light image of the “B” appears on a darker background of the radiograph,
protection from backscatter is insufficient and the radiograph shall be considered
unacceptable.
IQI Sensitivity
For the wire type IQI:
%Sensitivity = (Diameter of the smallest visible wire / Thickness of metal) * 100
For the step-hole IQI:
%Sensitivity = Diameter of the smallest visible hole / Thickness of metal * 100
For the plaque hole IQI, % of Sensitivity = square root of (AxB/2)
A is thickness of the smallest plaque image visible, expressed as a percentage of metal thickness
B is the diameter of the smallest hole visible, expressed as a percentage of metal thickness

21. Radiography Techniques
Selection of Technique based on
o Test Object – material/thickness/configuration
o Weld/Casting/Forging/Assembled part
o Anticipate location and nature of discontinuities
o Critical and vulnerable locations
o Sensitivity level required
o Accessibility of Film

22. Radiography Techniques
Types of Techniques
Single wall Single Image (SWSI)
o Flat Surfaces/Plates/sheets/Large Pipe Joints (Dia> 8”)
o Film Inside, Source Outside
Single Wall Single Image (SWSI) – Panoramic
o Film Outside, Source Inside
Double Wall Single Image (DWSI)
o Film Outside, source outside (External Exposure), Dia of Pipe > 3inch
Double Wall Double Image (DWDI)
o Film Outside, source outside (Elliptical Exposure), Dia of Pipe <3inch

23. For Panaromic, Multiple films are used and films must be same type
One Inch film to be overlapped with other
Single Shot, No of IQI to be calculated

24. Double Wall Single Image Double Wall Double Image
SOD wrt Top wall 0
SOD=Pipe Dia
Source Outside, Film Outside
Source Displacement Angle
Ø = 360 /n where n is odd, n= no of shots
Ø = 180 /n where n is even
Source Outside, Film Outside
Exposing Time will be double
Only 2 Shots required
Elliptical image will be observed
(OD/ID > 1.4)x1.7 = XX shots
(OD/ID < 1.4) =2 shots
OD – Outer Diameter, ID – Inner Diameter
For Example
OD= 50mm, t=12.5, ID = 25 N=?
(OD/ID > 1.4)x1.7 =3.4 ~ 4 Shots

25. Reference Source - ASNT Section 5

26. Reference Source - ASNT Section 5

28. Defects
o Casting
o Welding
o Forging
o Rolling
o Assembly
o Faults occurred during Handling/ Film Processing

29. Type of Defects - Casting
Defect Shape Location Indication
Shrinkage Linear Surface/Internal Black Line
Hot Tears Linear Surface Black Line
Cold Shuts Linear Surface Black Line
Porosity Round Surface/Internal/Root Black Spot
Non Metallic/Metallic
Inclusions
Round Surface/Internal Black/White Spot
Defect Shape Location Indication
Lack of Penetration Linear Root Black Line
Lack of Sidewall Fusion Linear Internal Black Line
Porosity Round Surface/Internal/Root Black spot
Slag Inclusions Round Internal Black/White Spot
Type of Defects - Welding

30. Four Pases in Weld
a) Root
b) Hand pass
c) Fill
d) Cap
Root Pass(Bottom side of Welded piece) Cap Pass (Top side of Welded piece)
Defects in Welding

31. Defects in Welding
o Lack of Penetration
o Lack of Fusion
o Porosity Cluster Porosity
o Slag Inclusions
o Root Undercut
o Crown Undercut
o Mismatch
oInadequate Weld Reinforcement
o Excess Weld Reinforcement
o Cracks
o Weld Spatter
o Arc Strike
o Tungsten/Oxide Inclusions (In TIG Welding)
o Whiskers / Burn through ( In MIG Welding)
Types of Defects

32. Defects in Welding

33. Defects in Welding

34. Defects in Welding

35. Casting Defects Can be classified as
Filling related defect
oBlow Hole
oSand Burning
oSand Inclusion Cold Lap/Cold Shut
oMisrun
oGas Porosity
Shape related defect
oMismatch /Misrun
oDistortion/Wrap
oFlash
Thermal defect
oCrack/Tears
oShrinkage - Cavity/ Dendritic/Filamentary/Sponge
oSink Mark
 Defect by appearance
oMetallic Projections
oCavities
oDiscontinuities
oIncomplete casting
oRat Tail/ Buckles
Types of Defects

36. Defects in Casting
Sand Inclusions Porosity Cavity Shrinkage Dendrite Shrinkage
Cracks Slag Inclusion Core Shit Sponge Shrinkage

37. Defects in Forging Process
oUnfilled Section
oCold Shut
oScale Pits
oDie Pits
oImproper Grain Flow
Defects in Parent Material
o Surface Irregularities – Rust/weld spatter/notches/ grooves/ loose scale
o Surface Roughness
oPorosity
oInclusions Metallic/Non Metallic
oLaminations/High Hydrogen Content
Types of Defects

38. Faults Associated with Storage
o Light Fog – Exposed to light while yet covered with interleaving paper
o Radiation Fog – Exposed to X Rays or Gamma rays during storage
Faults Associated with Safelight
o Safelight Fog – Higher capacity lamp used
Film has been allowed to stand under safelight Illumination too long period
White light is leaking from a slit in the safelight box
Faults Associated with Before Development
o Dirt Deposit on intensifying screens
o Dark Spots due to low density and Hugh density
o Water Spattered/Fixer Solution on film
Types of Defects

39. Faults Associated with Loading and Unloading
o Film Adhesion – Cassette adhered to intensifying lead screens
o Static Marks - Contact, peeling of foreign matter bcoz of electricity
o Kink Marks – Bents occurred during handling
Faults Associated with Post Development Process
o Uneven Fixing
o Uneven Drying
Types of Defects

40. Radiographic Interpretation in Steel Casting
ASTM E 446 - Reference Radiographs for Steel Castings Up to (51 mm) in Thickness
ASTM E 186 - Reference Radiographs for Heavy-wall (51 mm- 114 mm)) Steel Castings
ASTM E 280 - Reference Radiographs for Heavy-walled (114 to 305 mm)) Steel Castings
MIL STD 1265 A Radiographic Inspection, Classification & Sound Requirements for Steel Castings
Classification of Classes:

41. Radiographic Interpretation in Steel Casting

42. Aluminium Casting Defects
ASTM E 155 - Reference Radiographs for Inspection of Al & Mg Castings
MIL STD 139 A Radiographic Inspection, Soundness Requirements for Al & Mg Castings
Classification of Classes:

43. Acceptance Criteria for Al & Mg

44. Copper base & Nickel Copper Castings
ASTM E 155 - Reference Radiographs for High Strength Copper–base & Nickel-Cu Alloy Castings

45. Film Identification
Each radiograph shall be identified through the use of lead markers(numbers and letters).
The identification shall be as specified by the client but should consist of :-
1. Project Identification
2. Component, Casting, Pressure Vessel or Piping identifications
3. Seams or welds identification
4. R for repair, R2, R3 etc. if more than one repair.
5. C for new weld following complete cut out
6. Date of radiography
7. Welders identification

46. Film Viewing
o Equipment used to view radiographs for interpretation shall have a variable light source
sufficient for the essential designated IQI wire to be visible for the specified density range
of 2.0 to 4.0 High intensity light sources shall have exhaust arrangements for cooling to
prevent film damage
o Light from the viewer not transmitted through the film shall be masked when viewing the
radiograph.
o Calibrated densitometers or step wedge films shall be used to assure film density
compliance
Film Interpretation
o Radiographs shall be interpreted by Level II or Level III personnel
o Acceptance level shall be as per relevant Standard / project code

47. Quality Of Radiographs
All radiographs shall be free from mechanical, chemical or other blemishes to the extent that
they do not mask and are not confused with the image of any discontinuity in the area of
interest of the object being radiographed. Such blemishes include
a) Fogging
b) Processing defects such as streaks, watermarks, or chemical stains
c) Scratches, finger marks, crimps, dirtiness, static marks, smudges or tears
d) False indications due to defective screens.

48. Radiographic Testing Acceptance Standard For Weld
As per ASME Sec VIII, Div. I
a) All Welded joints surfaces shall be sufficiently free from coarse ripples,grooves, overlaps
and abrupt ridges & valleys to permit proper interpretation of radiographic and the
required non-destructive examinations. If any Default found on Surface, the film shall be
compared to the actual weld surface for determination of acceptability.
b) Indications shown on the radiographies of welds and characterized as imperfections are
un-acceptable under the following condition:
1) Any indications characterized as a crack or zone of incomplete fusion or penetration.
2) Any other elongated indication at radiography, which has length greater than:
(a) 6mm for t up to 19mm
(b) 8 mm for t from 19mm to 57mm
(c) 19mm for t over 57mm
Where: t= thickness of weld excluding any allowable reinforcement.
3) Any group of aligned indications that have an aggregate length greater than ‘t’ in a length
of ‘12t’ , except when the distance between the successive imperfections exceed 6L
where L is the length of the longest imperfection in the group.
4) Rounded indications in excess of that specified by the acceptance standards given in
ASME sec. VIII, DIV I, appendix 4 fig. 4-2 to 4-8

49. Defect Removal for Welding
Repair area shall be located on the weld line after evaluation & interpretation of radiograph
defects shall be removed by suitable method such as grinding, chipping or gouging (if permitted)
welding of the repair area shall meet the requirement of related WPS,PQR.
Certification And Personnel Qualification In Radiographic Testing.
Personnel performing radiography examination to this procedure shall be qualified and certified
by XXX Company also shall meet the requirements of ASNT-SNT-TC-1A-2001 EDITION at least
level II and on ASNT-SNT-TC-IA for code section I and sec VII div 2.
Film interpreter shall have level II as a minimum

50. Report Format (General Electric, US)

51. Checklist for Reviewing Radiographic Inspection

52. Precautions for Radiation Safety
o Shielded Enclosures and Exposure Devices are manufactured in compliance with
authorizations, appropriately surveyed and followed by quality objectives
o Personnel are trained and competent to operate the exposure devices safely
o Approved Operational procedures are to be followed
o Sources are sealed and leak free
o Source to be maintained in safe and secure condition at end of use or are
decommissioned properly
o Every personnel involved in radiography shall wear personal monitoring film badge.
o Radiation warning signs shall be posted at sufficient locations along the rope and
monitored by the technician.
o Fire and safety regulations of clients shall be adhered to at all times.

53. Measurement of radiation as per MIL – HDBK 728
Used to monitor amount of radiation received by man
Measured in REM- Roentgen Equivalent Man
Wrist Watch DosimeterPocket Dosimeter

54. Computed Tomography
o Computed Tomography (CT) is a powerful non destructive evaluation (NDE) technique
for producing 2-D and 3-D cross-sectional images of an object from flat X-ray images.
o Characteristics of the internal structure of an object such as dimensions, shape,
internal defects, and density are readily available from CT images.
o The component is placed on a turntable stage , b/w radiation source and imaging system.
o The turntable and the imaging system are connected to a computer.
o The imaging system produces a 2-D shadowgraph image of the specimen just like a film
radiograph.
Schematic View of a CT system

55. Pressure Vessel Inspection
The failure of a pressure vessel can
result in the rapid release of a large
amount of energy. To protect against
this dangerous event, the tanks are
inspected using radiography testing.

56. Thank You…