X ray radiography

By,
Pavan Girish Pandit
1
BMSCE, Bangalore 4/19/2017

 Introduction
 Process
 Case Study
 Xray vs Gamma ray Radiography
 Conclusion
2BMSCE, Bangalore 4/19/2017

 NDT process
 Used to detect
 Built in flaws
 Porosity
 Voids
 Fibre mis-orientation
 Thermal or shrinkage cracks
 Uses low energy Xrays from 10kV to 150kV
 Gamma rays are also employed
 Americium 241

 Thin sections of aluminium and composite specimens such as brake liners and clutch
facings of the automobiles.
 Mainly GFC (Glass Fibre reinforced Composites) are used in this application

 E1742- Radiographic examination
 E94- Radiographic exam
 E543- agencies performing NDT
 545-14- Neutron Radiography
 2663 and 2699 – Ultrasonic and Radiography
 748-16 – Thermal neutron RG of materials
 E49-04 – Std guide for Radiographic examination
 2662-15- Standard practice for radiography exam of flat panel

 NCRP 116 limitation on exposure
 NCRP 144 Particle accelerator
 Shield design and evaluation of medical and research usage of Xray and Gamma rays

 Heterogeneous
 Anisotropic
 Multi layered structures
 Defects in the interfaces

 The radiation source emits energy that travels in straighter lines and penetrates the
test piece.
 As the radiation energy passes through the test piece, an image, is received on a
recording medium opposite to the X-ray source
 This image is used for evaluation of the condition of the part being tested.

Radiography testing of thin sections of Aluminium
components
12

 Agfa-Gaevert D-7 film was used for Preparing Exposure charts
 Charts are used to calculate exposure time to obtain a optical density of 2.0 Gamma
rays.
 Source of Gamma radiations was 370 GBq of Am-241-Be
 Source film distance- 25cms
 Effective diameter of source, through pin-hole radiography was 4mm
 Radiation intensity was 75mR/hr
 Exposure time ranges from 2-60hrs
 No intensifying screen

 Xray source was Beryllium
 Effective focal spot diameter- 1.5mm
 Operation current 4-8mA
 Operating voltage 40-80kV
 Exposure time 0.5 to 1.3mins
 Focus to film distance- 7.5 cms
 No intensifying screen
 Exposed films were manually processed

Fig 1 Fig 2 Fig 3 Fig 4 Fig 5 Fig 6
The radiographic sensitivity of various thickness of aluminium, obtained with DIN type IQI for various X-ray energies and
Am-241 gamma rays, is plotted in figure-9. The best sensitivity of 2.7 % is attainable with Am-241 gamma rays at 9 - 10
mm of aluminium, while with X-rays 2 -2.5 % sensitivity is achievable. Lower sensitivity with Am-241 could be due to the
fact that the effective size of Am-241 source used was 4.0 mm in diameter, whereas X- ray source has focal spot of 1.5 mm.
Also the FFD used for X -rays was 75 cms in comparison to SFD of 25 cms with Am -241. It was not feasible to increase the
SFD in case of Am-241 source as the exposure time would have become unaffordable. 15BMSCE, Bangalore 4/19/2017

 Am-241 source can produce better radiographs than the ones produced by the low
energy X-rays.
 Source of high activity
 To reduce exposure time
 Improve sensitivity by increasing SFD (source to film distance).

Use of X-ray radiography in finding defects in MMC
By K. GAWDZIÑSKA, J. GRABIAN, W. PRZETAKIEWICZ
18

 Comparative studies concerning the weakening of X-ray radiation going through the
studies samples showed slight differences in optical density of the radiogram
 In all cases, for a cast thickness 10mm, discontinuity of 0.3mm is recorded
 The examination maybe used in diagnostics of composite casts, and maybe used
especially useful in detecting the size of a detect like porosity.

22
Nucleation in a composite

X ray radiography

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