NDT TRAINING METHOD IN CHENNAI
RADIOGRAPHY TESTING(RT)
INTRODUCTION
RT is based on exposure of the components to short wave length electromagnetic radiation in the form of x-rays or gamma rays from the suitable source. The amount of radiation absorbed by a particular part is a function of its thickness & density.
This radiation variation can be detected with the aid of photographic films.
False interpretation of film will affect productivity.
Only certified personnel can able to interpret the result.
PROCEDURE
ASME SEC: V Article: 2 /Article: 22
PRINCIPLE
Penetration & Differential Absorption
PROPERTIES OF ELECTRO MAGNETIC RADIATION
Reflection, refraction & diffraction.
Penetration
Absorption
Ionizing ability
TYPES OF RT
X-RAY
Gamma-RAY
STEPS BEFORE RT
Request.
Barricade Rope
Survey Meter
Dosi Meter
Film Badge
Penetrometer
Selection of film
Lead number box
Selection of source.
ADVANTAGES
Can be used to inspect virtually all materials.
Detects surface and subsurface defects.
Ability to inspect complex shapes and multi-layered structures without disassembly.
Minimum part preparation is required
Permanent test record is obtained.
DISADVANTAGES
Extensive operator training and skill required.
Access to both sides of the structure is usually required.
Field inspection of thick section can be time consuming.
Relatively expensive equipment investment is required.
Possible radiation hazard for personnel.
Depth of discontinuity is not indicated.