Longitudinal cracks on boiler reheater tubes
Longitudinal cracks on boiler reheater tubes
(OP)
Hi Guys,
I work at a coal fired power plant as a maintenance engineer and lately we have been facing the issue of boiler reheater tubes cracking at bends. I have attached couple of pictures of last two events. One tube had the crack on the side of bent surface, while other on the outside of bent surface.


This appears to be lip fracture (fish mouth?). I have suggested to perform hardness and metallography of the affected tubes. Will that be helpful?
Any help will be appreciated in helping us solve the problem as this is causing forced outages at our plant.
Regards,
Aleem
I work at a coal fired power plant as a maintenance engineer and lately we have been facing the issue of boiler reheater tubes cracking at bends. I have attached couple of pictures of last two events. One tube had the crack on the side of bent surface, while other on the outside of bent surface.


This appears to be lip fracture (fish mouth?). I have suggested to perform hardness and metallography of the affected tubes. Will that be helpful?
Any help will be appreciated in helping us solve the problem as this is causing forced outages at our plant.
Regards,
Aleem





RE: Longitudinal cracks on boiler reheater tubes
RE: Longitudinal cracks on boiler reheater tubes
The material for these tubes are SA 213 TP347h and the operating temperature is around 540C
RE: Longitudinal cracks on boiler reheater tubes
Get these to a metallurgical lab for complete analysis. If this is not SIPH it could be cracking related to condensate trapped in bends during off-line conditions. Look at the ID if you can and evaluate the surface.
RE: Longitudinal cracks on boiler reheater tubes
After we perform the metallurgical analysis, I will get back with the results and the suggestions provided by lab for any input from eng-tips.
Thanks again.
Aleem
RE: Longitudinal cracks on boiler reheater tubes
It could be useful to look at the degree of sensitization/stabilization at various locations in the tube, variations in thermo-mechanical history could be part of this.
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube
RE: Longitudinal cracks on boiler reheater tubes
RE: Longitudinal cracks on boiler reheater tubes
RE: Longitudinal cracks on boiler reheater tubes
Since this is H material there will always be some mix of sensitization and stabilization, but too much of hte first and you are screwed.
But at the same time nobody wants to pay for bending, solution anneal, and stabilization, even though that is the correct way to do it.
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube
RE: Longitudinal cracks on boiler reheater tubes
RE: Longitudinal cracks on boiler reheater tubes
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube
RE: Longitudinal cracks on boiler reheater tubes