Material selection in high temp. dry HCl gas service

[Hermess]

Hi, everyone.

I am hermess, first step material engineer. So I need your help regarding material selection.

*process service
Operating temp. 550’C
Design temp. 650’C
Fluid: dry HCl gas
Piping parts

In the above service, I think stainless steels such as 304H, 316H can be used.
But I worry about sensitization (Intergranular corrosion) and sigma phase embrittlement.

Generally when we worry about sensitization, L grade (Low carbon content) stainless steel shall be used due to reducing CrC formation

But when we worry about sigma phase embrittlement, H grade (high carbon content) stainless steel shall be used due to reducing sigma formation from FeCr

My concern is that above service is applied to both.

So I want to know which type of stainless steel can be used, L grade or H grade.

Also I find some information regarding dry HCl gas corrosion from ASM handbook vol.13 page 1165.
According to ASM handbook, stainless steel 304, 316 can be used upto 400’C due to corrosion by dry HCl gas. Is it true?

In above service, what is the best choice, I mean material selection.
I think that Alloy 800H is suitable for this service, but as know, alloy 800H is very expensive. Is application of alloy 800H necessary? Stainless steel 304H is not reasonable?

Please inform me regarding this matter.

thank you for reading

Best regard.

 

[Goahead]

You may wish to see the following document:

Alloys to resist Chlorine, hydrogen chloride and hydrochloric acid

http://www.nickelinstitute.org/index.cfm/ci_id/3154/la_id/1/document/1/re_id/0

Regards,

http://www.welding-advisers.com/

 

[Hermess]

Thanks Goahead

It is useful.