CREEP RUPTURE STRENGTH FOR GRADE T23 3

[ATsampalas]

Can someone help to find Creep Rupture Strength for Tubes Grade T23 (SA 213 Grade T23) 10000H + 100000H + 200000H ?
a) Grade T23 is defined in Code Case 2199-3 and ASME-2A+D but neither of them give any answer to our problem .
b) The German Stahschlüssel (Key to Steel) gives an additional parameter UNS Nr K40712 but remains unsuccessful.
c) Euro-Norms give an additional equivalent material :
7CrWVMoNb9-6 which is not exploitable...
d) These Rupture Strength values are needed for In-service life expectancy calculations (according to EURO-NORMS) .

Sincerely,

A_Tsampalas

 

[metengr]

ATsampalas;
There was an excellent technical paper on qualification of this material for Code Case approval. I thought there might be a link to this paper on this forum.

Title;Development of a New Class of Fe 3Cr-W(V) Ferritic Steels for Industrial Processes Applications


Primary Investigator; Jawad

Oak Ridge National Lab
Exxon Mobile

 

[davefitz]

There have been papers published in the last 2 yrs on this subject , at the ASME PVP conferences and at the EPRI florida conf on advanced materials last year.

 

[unclesyd]

Here is the paper that meteng referenced.

http://www1.eere.energy.gov/industry/imf/pdfs/1763ferriticsteelsfinal.pdf

 

[davefitz]

unclesyd + meteng:
I read the referenced paper, and they indicate one objective was to reduce the shipping weight of thick vessels ( were 8" thk, to be < 5" thk with T23) using a bainitic alloy such as T23. Unless they are considering using ribbon wound technology, a monolithic 5" thk vessel would have a difficult time forming a bainitic crystal structure upon cooldown- isn't the main reason T23 has not been applied to thick walled piping is the need to cool quickly to form the bainite?

 

[metengr]

davefitz;
The original Code Case approval for Grade 23 was in tube and pipe product forms. I don't believe this material could be used to manufacture thick-walled headers because of the concerns related to reheat cracking, and not necessarily related to the formation of a bainitic microstructure through-out.

Despite the fact that this material demonstrates excellent weldability in tube and pipe product forms (similar to Grade 22 because of the bainitic microstructure) welding under conditions of restraint creates the potential for lack of ductility unlike that found in Grade 22 thick-walled components. However, I need to track this down to confirm the reheat cracking issue, but this is what I remember in my code activities.

 

[davefitz]

according to the mannespan " the T23/ T24 book" CCT diagram for T23, bainite will form as long as the component is cooled down from 1940 F to 500 F within 5 hrs- pretty flexible requirement ( about 5 F / min)