Tube Wall Reduction for Alloy 825 Tubes

[htman]

Can anyone give me a recommendation for the tube wall reduction on SB-163 N08825 tubes? I want to roll my tube to tubesheet joint but not sure what my target tube wall reduction should be (wall reduction measured in percentage of tube wall thickness.

Thanks

 

[metengr]

htman;
Please answer the following;

1. Tubesheet material?
2. Grooves in the tubesheet?
3. Seal welded after roll expanding?
4. Service application - new construction or in-service re-tube?
5. Are you going to qualify a tube rolling procedure?

 

[htman]

Metengr,

1. tubesheet material: SA-387 Gr 11 Cl 2
2. No grooves
3. strength welded tubes
4. new construction
5. test fixture per Artcle F-3 ASME Code

thanks

 

[Christine74]

As a starting point, take a look at the chart at the bottom of this page:

http://209.85.173.104/search?q=cache:4XvfglIPIasJ:

http://www.elliotttool.com/media/ex..."+"Max+Wall+Crush+%"&hl=en&ct=clnk&cd=1&gl=us

-Christine

 

[metengr]

I would proceed with extreme caution. The tubes are strength welded so roll expanding to a certain percentage before and after welding will be applicable. The two stage rolling is to assure the tubes are initially locked into the tubesheet prior to welding, and the second or final roll expansion (after welding) is to assure uniform leak tightness to avoid contaminants reaching the weld root in service.

The key for this job will be to qualify a tube roll/weld procedure using a mock-up and pull tests.