Failed boiler tubes

[sunshine419]

I appreciate the shared knowledge of experts in the house and I guess this forum has been of great help to upcoming young stars who aspire to grow in the profession.

Without further ado, I have two in - service failed package expansion boiler tubes. The tubes had failed at the interface between the boiler tube and tube plate on the waterside of the firetube – type package boiler. I’ll like to know if anyone has had similar experiences in the past and what could be the possible cause(s) of failure (see attached as-received pics).

Any suggestions on recommended text would also be appreciated. Thanks

 

[metengr]

sunshine419;
Unfortunately, one picture is not going to be definitive. What is the appearance of the ID surface of the failed tubes? Is there wall thinning from the ID surface?

Several general observations – the first being one end of each tube appears to have been rolled into a tubesheet. The second observation is that both tubes appear to have different outer diameters -is this because they are at different locations in the tubesheet or is this just an image from the photograph? Third observation - the axial gouges actually appear to me like either severe internal corrosion that resulted in a breakout of tube material (which could be confirmed by a wall thickness survey) or damage from local arc gouging. I have seen where tubes have been removed by slitting the tubes along their length by carbon arc gouging to extract them from a tubesheet.

Send these out to a metallurgical lab for destructive examination.