AL-6XN (UNS-N08367), can it be used as a coil material inside a boiler(Complying with Sec I) ?

[jtseng123]

Dear all,

I was asked the following question. Can anyone shade a light on it:

"AL-6XN (UNS-N08367), can this material be used as a coil material inside a boiler(Complying with Section I) ?

 

[metengr]

This material is not permitted for use in Section I as pressure retaining material. It can be used in non-pressure retaining applications.

 

[metengr]

PS - I don't recall if there was a code case for this material (at least since I have been a member of Section I).

 

[EdStainless]

There was a code case, but I don't think it was for Sec 1 service.


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Plymouth Tube

 

[metengr]

The code case was for Section VIII, Div 1 and was encorporated some time ago. There are stress lines for this material in Section II, Part D for use in Section VIII, Div 1, but still not permitted for Section I.

 

[EdStainless]

There are fairly limited upper temperatures on these 6% Mo alloys.
With long term exposure anything over 950F is dangerous.


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Plymouth Tube