where expertise comes together - since 1996 -

The Largest Open Access Portal of Nondestructive Testing (NDT)

Conference Proceedings, Articles, News, Exhibition, Forum, Network and more

where expertise comes together
- since 1996 -
1049 views
Technical Discussions
Dent McIntyre
Consultant, NDE Manager NDELevel III/3
NDT Consultant, Canada, Joined Nov 1998, 250

Dent McIntyre

Consultant, NDE Manager NDELevel III/3
NDT Consultant,
Canada,
Joined Nov 1998
250
00:47 Mar-29-1999
Penetrant Test of vessel under pressure

A vessel is under Helium pressure at 100 PSI for the purpose of performing a Helium Leak test.
A tiny Inconel weld on the vessel needs to be PT inspected but was not done prior to pressurizing.
What effect will this have on the penetrant test?


 
 Reply 
 
S.V.Swamy
Engineering, - Material Testing Inspection & Quality Control
Retired from Nuclear Fuel Complex , India, Joined Feb 2001, 787

S.V.Swamy

Engineering, - Material Testing Inspection & Quality Control
Retired from Nuclear Fuel Complex ,
India,
Joined Feb 2001
787
09:45 Aug-16-2002
Re: Penetrant Test of vessel under pressure
Pressurisation of the vessel will have a tendency to slightly expand the vessel, thus there will be a tensile stress on the outer surface. This will slightly magnify the size of any discontinuity that may be present. So, the best course is to 'retest' the same weld after the pressure test is completed and the internal pressure removed, before attempting to 'size' the discontinuity and apply the specification for acceptance and or repair.

: : A vessel is under Helium pressure at 100 PSI for the purpose of performing a Helium Leak test.
: : A tiny Inconel weld on the vessel needs to be PT inspected but was not done prior to pressurizing.
: : What effect will this have on the penetrant test?
: ..
.



 
 Reply 
 
rodney fordham
rodney fordham
03:55 Aug-16-2002
Re: Penetrant Test of vessel under pressure
:A partial thickness crack on the outside of a pressure vessel wall opens slightly when the internal pressure is applied. The more sensitive interferometric techniques reveal that the vessel bulges a little in the vicinity of the crack. Does anyone know what the relative importance of internal and external partial thickness cracks is? Clearly the external cracks are more weakening than internal?
====================
: Pressurisation of the vessel will have a tendency to slightly expand the vessel, thus there will be a tensile stress on the outer surface. This will slightly magnify the size of any discontinuity that may be present. So, the best course is to 'retest' the same weld after the pressure test is completed and the internal pressure removed, before attempting to 'size' the discontinuity and apply the specification for acceptance and or repair.
.
: : : A vessel is under Helium pressure at 100 PSI for the purpose of performing a Helium Leak test.
: : : A tiny Inconel weld on the vesselneeds to be PT inspected but was not done prior to pressurizing.
: : : What effect will this have on the penetrant test?
: : ..
: .
.



 
 Reply 
 
Dent McIntyre
Consultant, NDE Manager NDELevel III/3
NDT Consultant, Canada, Joined Nov 1998, 250

Dent McIntyre

Consultant, NDE Manager NDELevel III/3
NDT Consultant,
Canada,
Joined Nov 1998
250
05:36 Aug-19-2002
Re: Penetrant Test of vessel under pressure
Pressure inside a vessel especially (helium)will inhibit the capillary action of the penetrant in entering leaks. The thru wall leak may not be detected with the penetrant test.
Furthermore, penetrant could also plug a tiny leak and make it undetectable with the helium test.

This information comes from a recent experience of a vessel similar to the one described.
For more information e mail me directly.


: :A partial thickness crack on the outside of a pressure vessel wall opens slightly when the internal pressure is applied. The more sensitive interferometric techniques reveal that the vessel bulges a little in the vicinity of the crack. Does anyone know what the relative importance of internal and external partial thickness cracks is? Clearly the external cracks are more weakening than internal?
: ====================
: : Pressurisation of the vessel will have a tendency to slightly expand the vessel, thus there will be a tensile stress on the outer surface. This will slightly magnify the size of any discontinuity that may be present. So, the best course is to 'retest' the same weld after the pressure test is completed and the internal pressure removed, before attempting to 'size' the discontinuity and apply the specification for acceptance and or repair.
: .
: : : : A vessel is under Helium pressure at 100 PSI for the purpose of performing a Helium Leak test.
: : : : A tiny Inconel weld on the vessel needs to be PT inspected but was not done prior to pressurizing.
: : : : What effect will this have on the penetrant test?
: : : ..
: : .
: .
.



 
 Reply 
 

Product Spotlight

NDT.net launches mobile-friendly design

NDT.net has revamped its website providing a mobile-friendly design.The front page received a comp
...
letely new design and all other sections are now reacting responsively on mobile devices. This has been a major step to make our website more user- friendly.
>

NEW Wheel Type Phased Array Probe

DOPPLER NEW Wheel Type Phased Array Probe, more stable, new tyre makes lesser acoustic attenuation
...
, much lighter makes easier to handle, more slim size, magnetic and mechanical encoder optional etc...more
>

Cygnus 6+ PRO Multi-Mode Ultrasonic Thickness Gauge

The Cygnus 6+ PRO thickness gauge is the most advance gauge within the Cygnus range with key featu
...
res including: comprehensive data logging; A-scan and B-scan display; manual gain control; Bluetooth connectivity; and much more. With its unique dual display and three measuring modes (Multiple-Echo, Echo-Echo and Single-Echo), this surface thickness gauge offers maximum versatility for inspections.
>

Varex Imaging Large Field of View (FOV) Digital Detector Arrays (DDAs)

A larger FOV DDA can reduce the space and volume of the X-ray inspection system on the factory floor
...
, enable faster scanning times, better throughput and better resolution images at a lower dose. Customers can also save time and money. With these benefits in mind, Varex Imaging has designed a family of large FOV detectors (4343HE, XRD 1611, 4343DX-I, 4343CT) for our industrial imaging customers.
>

Share...
We use technical and analytics cookies to ensure that we will give you the best experience of our website - More Info
Accept
top
this is debug window