Fabrication problems associated with 13 Cr tubes

[mkolwankar]

I have following metallurgy combinations for S&T Heat Exchangers. I would like to know any fabrication limitations with the below metallurgy for tubes & tubesheets.

For one exchanger
Tube Material - 13 Cr
Tube sheet material - CS + 13Cr cladding on both sides
Tube - Tube sheet joint - Expanded in two groves

For other exchanger
Tube Material - 13 Cr
Tube sheet material - CS + 13Cr cladding on tube side
Tube - Tube sheet joint - Expanded

Thank you.

 

[weldstan]

Best to use ferritic alloy (405, 409, 410S) grades from a welding standpoint.

 

[EdStainless]

Watch the expansion carefully. Use roller expanders (not hydro) and make sure that the tubes are not cold when you expand them.
These alloys are not as forgiving as 300SS so you need to make sure that your mock up and rolling tests are done very well.
And you tubesheet hole control needs to be better than normal.


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P.E. Metallurgy, Plymouth Tube

 

[metengr]

Better develop a rolling procedure and qualify the procedure using a mock-up.