Welded Curtis Wheel

[vali1]

Hi everybody!

I have a problem.
An Welded Curtis Wheel- from an 8MW Steam turbine.
I have to reblade integraly this stage. But I don't have the right technology(procedure)for the welding. A particularity of this stage are the holes from the rooth of the blade, right between rooth of the blades.

1. Can someone give me an explanation regarding this holes?
2. A brief description of the welding procedures for welded blade on disk will be wery good.Or at list an web adress.


Thank you!

 

[metengr]

Yes, I can tell you that weld repair of a Curtis stage on a small turbine requires specific welding expertise, and knowledge of turbine metallurgy, and nondestructive testing. I believe the holes in this wheel are for steam balancing purposes and need to be duplicated.

Regarding welding, I would contact three (3) turbine OEM's that offer rotor welding capability (GE, W and ABB), and seek repair proposals from them. I have dealt with all three of these vendors on turbine rotor welding, and they can work with you on this project. This is a rather complex project and trying to obtain this information on the internet will not be successful.

 

[vali1]

Thank you!

But one of the major problem.... is:

The firm I work for is in charge with the scope of work, and...

I have just some global ideas about welding this blades.

By the way, recently I found some materials, and it is possible that the hole is for stress release.

I am steel waiting for some clarification.

Thanks!

 

[metengr]

You can always subcontract the weld repair work for the Curtis stage. Turbine rotor welding is an expertise, and is not to be taken lightly.

 

[byrdj]

1) the holes - Ideal Curtis is an impulse wheel, thus there should not be any pressure drop across the wheel. All pressure drop occurs in diapragm as its discharge is velocity. Since design is not 100% ideal, there will be some pressure drop across wheel and if it was not for the equalizing holes in the wheel, the thrust load on the rotor would increase.

2) Welding rotating components - Besides the OEMs, there are a lot of spin off service shops in the US that not only duplicate the OEMs, but have developed there own expertise