Support welded without Flush grinding the seam

By engineertwo Date 02-12-2008 07:17

Deal All,

A Saddle support is welded on a Spiral welded API pipe without flush grinding the weld seam. What is the danger exposed to the portion of weld seam remains under the support. What is the remedy to be done to rectify if this is not an acceptable method of fabrication. Thanks

By G.S.Crisi (****)

Date 02-12-2008 19:56

Is the saddle welded interely to the pipe or just with evenly spaced long tack welds?
In the first case, I see no danger at all. In the second case, if the weld is outdoors, rainwater will remain trapped between the saddle and the pipe.
In this case, three remedies are possible:
1. Weld the saddle interely to the pipe.
2. Caulk the clearance between the saddle and the pipe with a suitable product.
3. Paint the the areas of the saddle and the pipe that are in contact with a suitable water resisting paint.

Are there reliable water resistant paints? Yes, there are. Ask your paint supplier for help.
Giovanni S. Crisi
Sao Paulo - Brazil

By Bonniweldor (**)

Date 02-13-2008 02:35

One concern I would have is creating a transverse stress/strain along the ID toe line. In effect, the saddle would contact the OD weld and push inward along the contact. This would be augmented by the hoop stress when the pipe is under pressure. Stress cycling could promote fatigue crack initiation where the overstress is superimposed. If I were the Client, the weld absolutely would have been ground within 1/16" of flush.