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SA 285-C FBQ

SA 285-C FBQ

We have a 1951/52 vessel "alteration" to do and the shell material along with some very large nozzles and all reinforcement pads utilize SA 285-C FBQ material.  I know that FBQ means Fire Box Quality and I have seen it used with other materials also.  Does anyone out there know if all SA 285-C material is FBQ or is this some special version of SA 285-C.  You see FBQ more on much older vessels.  What does Fire Box Quality (FBQ) mean?

RE: SA 285-C FBQ

Fire Box Quality means suitable for use in a boiler firebox. Retains pressure and is exposed to flame. Such as a steam locomotive.

Check this site out.

RE: SA 285-C FBQ

Just to add to the above after a little digging around of my files;
Firebox Quality steel plate had tighter control over chemical composition to assure specified minimum mechanical properties prior to the development of SA 515 steel plate. SA-285 Grade C is not the same as fire box quality SA 285 Grade C. If anything, SA 515 plate would be an equivalent material substitution.

RE: SA 285-C FBQ

As an old steel maker, SA-285 Grade C, fire box quality, was fully deoxidized - Silicon killed.

RE: SA 285-C FBQ

I agree with metengr. It is unlikely you will find any FBQ and if you do the paper trail may not be there.

Have hand forged a couple of rear flue sheets in some restorations and used 515,but thats another story.

Do your calcs. and check with your AIA.

RE: SA 285-C FBQ

Additionally, the 1950 ASME Code information on SA 285-C FBQ material states 55k min. tensile, 1375psi allow. stress upto 650oF, 13k upto 700oF & 11900 upto 750oF.  Information from the 1951 drawings state this material shall have "shear test per ASME Code case #896 required (1948 ruling)".

Finally, I would like to especially thank metengr, deanc & stanweld for their insight and shedding light on this issue.  I want you to know that this small clarification has helped me and it has, once again, helped influenced my supervisors opinion of my ASME Code abilities.  I am appreciative of these replies and for Eng-Tips.

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