HTHA in Carbon Steel 1

[Guest102023]

I have the task of examining possible HTHA damage in aged carbon steel pipe removed from service. Little if any damage is suspected. The method is optical metallography.

I am looking for some experience and recommendations for a metallography protocol. How are welds and HAZs affected compared to base metals? At this point I plan to examined it unetched and then etched, at magnifications ranging from low to as high as possible.

I have reviewed API RP941 and RP571; the latter mentions surface decarburization. Given that many steels start service with surfaces already decarburized at the mill, how reliable is this?



"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

 

[metengr]

http://etd.lsu.edu/docs/available/etd-0409103-160949/unrestricted/Saba_thesis.pdf

 

[Guest102023]

Outstanding as always, a nice little synopsis of the problem.

Don't know where we would all be without you, metengr.

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

 

[EdStainless]

You might look up a paper by Mark Evans, The Potential UK Energy Gap and Creep Life Prediction Methods, Metallurgical and Materials transactions A, vol 44A, Jan 2013.
I found it on the internet.
It may not address your question, but the bibliography is a great resource of its own on this subject.

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Plymouth Tube

 

[Guest102023]

Thanks Ed,
I was unable to locate a version that did not request a large number of British pounds. Any hints?

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"