Questions regarding the ultrasonic testing method in non-destructive testing of pressure vessels
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In the current JB/T4730.1-4730.6-2005 standards, JB/T4730.3-2005 is the standard to be followed for ultrasonic testing; now, the Ministry of Energy has issued NB/T47013.10-2010, Non-destructive testing of pressure equipment – Part 10: Ultrasonic testing using the diffraction time difference method. I’m a bit confused now: which ultrasonic testing method is actually used in pressure vessels? Will JB/T4730.1-4730.6-2005 be replaced by NB/TT47013.10-2010 in the future? I’m not very familiar with non-destructive testing; please help me out if you understand this area.
Ultrasonic testing using the diffraction time difference method, known as TOFD, is currently considered to be a method that can replace RT testing. However, it is used little in China; efforts are being made to promote its development, with the hope that it will soon be able to partially replace RT testing
Ultrasonic testing using the diffraction time difference method, abbreviated as TOFD, is said to have a very high sensitivity in manufacturing workshops; as a result, they have to carry out quite a number of repairs
NB/T47013.10-2010 Non-destructive testing of pressure equipment – Part 10: Ultrasonic testing by diffraction time difference method. It is merely a supplement to JB/T4730; it cannot replace it at present
One is the diffraction method, and the other is the reflection method; as the saying goes, everyone has their own preference.
They are all ultrasound examinations, each with its own characteristics; the old and new standards are not substitutes for one another
TOFD has been widely used in China for roughly ten years now. Since many manufacturers have established their own corporate standards, the industry has also developed relevant standards in response to these developments. However, TOFD still has its limitations; it is difficult to apply it to welds on spherical heads. Currently, applications are also mostly limited to relatively thick containers