Re: Internal ligament inspection in economizer inlet header

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Re: Internal ligament inspection in economizer inlet header
Posted by: Ed Ginzel (PID_67), E-mail: eginzel@mri.on.ca, on December 23, 1999 at 21:37 :
In Reply to: Internal ligament inspection in economizer inlet header posted by : Jacques Parent on December 23, 1999 at 17:11:
Jacques:
Greetings!!!
In 1983 Dr. Michael Moles and Tony Allen were in Ontario Hydro Research (which I still call it)
and published a paper on the technique they came up with for the Economiser Inlet header cracking
that existed THEN, 17 years ago.
The paper was published in Materials Evaluation May 1984/vol 42/ no.6.
I suppose the technique you develop will depend on the type of access
you have. This sounds like an interesting one.
Crack sizing using tip diffraction can be used but you will want to detect the indications first.
Moles and Allen managed to flood the header and worked with an immersion setup using tandem probes.
We need more information about the problem before a working solution can be derived.
Regards
Ed

: I am looking for any information, paper, link or past experience on internal ligament inspection in economizer inlet header.
: Our company has experience of cracking in the economizer inlet header due to a corrosion-fatigue mechanism. The fatigue component resulting from thermal stresses generated by the admission of relatively cold feedwater into hot headers.
: We have discovered:
: -Longitudinal cracking in the tube stub
: -Cracking in the tube hole running parallel to the axis of the hole
: -Cracking from the internal lip of the hole toward adjacent holes in both longitudinal and circumferential directions (ligaments)
: We need an inspection technique to detect and size the trough-wall depth of the cracks.
: Thank you for your help
: jp

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Comments:
: Jacques: : Greetings!!! : In 1983 Dr. Michael Moles and Tony Allen were in Ontario Hydro Research (which I still call it) : and published a paper on the technique they came up with for the Economiser Inlet header cracking : that existed THEN, 17 years ago. : The paper was published in Materials Evaluation May 1984/vol 42/ no.6. : I suppose the technique you develop will depend on the type of access : you have. This sounds like an interesting one. : Crack sizing using tip diffraction can be used but you will want to detect the indications first. : Moles and Allen managed to flood the header and worked with an immersion setup using tandem probes. : We need more information about the problem before a working solution can be derived. : Regards : Ed : : : I am looking for any information, paper, link or past experience on internal ligament inspection in economizer inlet header. : : Our company has experience of cracking in the economizer inlet header due to a corrosion-fatigue mechanism. The fatigue component resulting from thermal stresses generated by the admission of relatively cold feedwater into hot headers. : : We have discovered: : : -Longitudinal cracking in the tube stub : : -Cracking in the tube hole running parallel to the axis of the hole : : -Cracking from the internal lip of the hole toward adjacent holes in both longitudinal and circumferential directions (ligaments) : : We need an inspection technique to detect and size the trough-wall depth of the cracks. : : Thank you for your help : : jp

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