During the NDE it was found that it has crack placed next to journal under thrust collar. On the picture below (arrow) it is visible - thrust collar is diassembled.
Firstly, the rotor end was cut and shaft chamfered. The stub shaft was sent to us by our colleagues and welded by TIG to the main part of the rotor. The most important activity was carried out next - putting the material by SAW. It took several days and was splited into a few phases. After welding certain material thickness we machined it and did NDE to be sure if weld is free from any mistakes.
When welding was done I took over the responsibility. The two last steps remain. The rotor PWHT and machining.
To perform PWHT the rotor had to be positioned vertically. It is not usual to see rotor set in vertical position and to do it the special equipment was necessary - based on former solution I designed some devices.
The pictures below show the rotor uplift:
- rotor after rough machinig before PWHT
- the rotor uplift
The rotor is hanging and will be fixed for PWHT
The rotor PWHT is starting ...
Original rotor design was changed. Just now the thrust collar is an integral part of the rotor shaft when previously collar was a seperate part and mounted on the shaft with negative allowance.
The repair last step carried out in our workshop and supervised by me was the final machining. I got the drawing, but the technology chart prepared on my own. As usually not all info was put on the drawing but I manged to get the missing data and below we can see the rotor end after final machining:
Once machinig was finished the rotor was moved to the our subcontractor - for high speed balancing.
I know that the customer has more rotors (2 pcs.?) with similar crack and maybe the repair process will done again... who knows...
