reaction turbine overhaul - part one

In my previous post I mentioned about reaction turbine overhaul projects I supervised in our workshop.
We repaired following parts of this turbine:
- rotor,
- upper outer casing,
- bearings,
- glands,
- internal casings (carriers - is it right technical word?) with stationary blades,

Like usually, the first step before any activity is to take a pictures of parts. It will be an evidence of parts conditions and ( in case when customer does not have documentation) helpfull in further overhaul steps.
The next move is cleaning/blasting and just now we eneter to this moment, which can affect the rest - NDT examination.
This step discovers the real condition of parts. All craks, defects will be found and decision what to do with them will be taken.
In overhaul, describing by me, we had a problem with one of internal casings (carrier).
We found that blade shrounds are not fixed to the blades.
Please see the photos of casing (carrier) no 1

It would be very dangerous to leave it as it is and against technical routines we follow.
Neither we nor customer did not expect such suprise so it was necessary to organize meeting and inform what we found and what are our proposals.
The best way to repair the shrounds would be to exchange the blades into the new ones and put new shrounds as well, but not in this case, as
1. customer was not prepared for such cost,
2. there is no time to carry out this - they need power and steam, so there is a must to fix the issue as fast as possible using enough appropriate technical solution to launch the machine and operate it for some time period.

After the meeting it was decided to applied our proposal - to weld the end of blade - tenon with the shround. This emergency repair will let customer to operate turbine till to next year when wider scope of overhaul has to be taken into consideration.
The repair idea given by my senior management was drew by me and below we have more detailed drawings.

We suspected what are the steels used to manufacture the blade and the shround - each OEM uses the same group of steel but to be sure in 100% the analysys was done. It was especially important for our welding engineers - to define and apply right welding technology. A few welding samples were made to precise post weld heat treatment as weld hardness after PWHT should be proper one. We managed to reach right parameters.

If major overhaul takes place, like we adviced, in 2010 I will have possibilty to check results of this emergency repair - it will be great issue.