NDE method
NDE method
(OP)
Result from a failure analysis on water tube (floor) from a packaged type boiler (type D) indicates cracking occur due to thermal fatigue.
What NDE method will be best to confirm or ruled out thermal fatigue damage in rest of tubes?
Thanks,
Corgas
What NDE method will be best to confirm or ruled out thermal fatigue damage in rest of tubes?
Thanks,
Corgas





RE: NDE method
I would have the failure and material analysed by a metallurist, you may be at or near end of life.
Good Luck
RE: NDE method
Is the thermal fatigue OD initiated damage?
RE: NDE method
Brand new boiler, only three years old. Failure analysis was done by qualified lab.
What's MPI?
If tubes are connected by "welded web" (membrane type), can we still apply shear wave UT?
Thanks,
Corgas
RE: NDE method
RE: NDE method
Cracking comes from ID and it is transgranular. Tubes are not covered by refractory but, section that failed (close to mud drum) it is supposed to be covered by refractory.
thanks,
corgas
RE: NDE method
What about a borescope? If you can access from the lower supply drum you can visually check for cracks on the ID surface. The remote field ECT will also provide the same results.
RE: NDE method
Some of them were checked by boroscope but not all. This mud drum is pretty small and narrow.
ECT means eddy current testing??
Thanks,
Corgas
RE: NDE method
Is the thermal fatigue damage circumferential or axial in the floor tubes?
RE: NDE method
Circumferential!!! You'd expect cracking around 6 o clock position but it actually showed at 12 o clock position.
Corgas,
RE: NDE method
another outfit i had worked with was Tordonato Energy Consultants. they have a complete metalurgical lab and some of their people were extremely knowlegable in failure analysis.
Steven C
Senior Member
ThirdPartyInspections.com
RE: NDE method
http://www.tordonatoenergy.com/
RE: NDE method
Not to commercialize any one vendor here, I know TEC and have worked with others below on various projects in the Power Generation sector. All are equally good.
http://www.structint.com/
http://www.mmengineering.com/
http://www.thielsch.com/
RE: NDE method
you're right, Thielsch is another good one i am aware of.
Steven C
Senior Member
ThirdPartyInspections.com
RE: NDE method
RE: NDE method
What is the size of the access?
How many tubes would need to be inspected?
If say you inspect 4 on each end and all have have problems you should seriously look at replacing all as you probably have a design problem. I would suspect that the call for insulation in this area was based on experience.
A comment on the location of the failure.
I've been involved in similar failures on a D tube boiler where the root cause was attributed to "steam blanketing" that allowed periodic heating and quenching of failure area. Our problem was attributed to rapid rate changes mainly due to implication of different instruments and a new control scheme.