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HANGZOU ADVANCE GEARBOX GWC6066 gearbox Inspection and repair

Inspection and repair on HANGZOU ADVANCE GEARBOX GWC6066 gearbox

  • HANGZOU ADVANCE GEARBOX gearbox
  • GWC6066
  • Input=___ rpm / ____ KW
  • Denmark

Scope of work:

We performed an inspection and repair on a gearbox HANGZOU ADVANCE GEARBOX GWC6066.


This client from Denmark came to us with this HANGZOU ADVANCE GEARBOX GWC6066. We inspected the gearbox and performed a repair. After a succesful testrun we shipped the gearbox back to the client.

This report presents the findings of the performed inspection onboard a ship. Location, Rotterdam, The Netherlands.

GBS international was invited to perform the below mentioned work.

Scope of work:

- Inspection Propulsion GBX, Hangzhou Advance GWC 6066

Micro pitting has been found on the following flanks:

- Intermediate shaft AHEAD gearwheel working flank (1st stage).
- Intermediate shaft AHEAD drum gear working flank (2nd stage).

The micro pitting is most likely formed in the last 2.5 months, the micro pitting could be initiated by small hard metal particles in the lubrication oil.

Micro pitting and in line pitting has been observed on the following flanks:
- Intermediate shaft AHEAD pinion working flank (3rd stage).
- Output shaft gearwheel working flank. AHEAD

In the report made in January 2018 there was cited: “At the intermediate shaft ahead pinion a fine pitting in line has been observed. This is the progressive phase of micro pitting, and will develop to pitting, and finally will result in flaking of the gears” “At the working flank of the Bull gear of the output shaft. The micro pitting is in advance stage.” Currently the micro pitting is in such an advanced stage that it can also be determined as starting pitting. Due to the small size of the electric turning motor the bull gear of the output shaft could not be turned, so only the teeth in the visible area could be inspected.

Micro pitting is a phenomenon that can be found on (hardened) gears. Multiple factors can affect the development of micro pitting, most important factors are surface roughness, lubrication or an incorrect gear mesh. The damage shows itself by a matted grey colour of the teeth. This as outcome of surface fatigue. The development of the micro pitting can be stabilized or progressive. On these gears the micro pitting is progressive, a progressive development can eventually cause more severe pitting, and scaling.

Bearings: Because of the known severity of damage on the bearings, the unknown running hours of the gearbox and the visible steel particles in the oil filters, GBS recommend to replace the bearings during an overhaul. This to avoid an un planned, destruction repair.

Overall condition:

In 2.5 months it is visible that the overall condition of the gearbox has worsened, the condition of the gears as well as the bearings has worsened. GBS expects no destructive breakdown within the next 2 months.

Recommendations

- Overhaul the gearbox, and order;
- Complete set of internals from Hangzou. P
- Buy a complete set of bearings for stock.
- It is recommended to perform an 3 monthly visual inspection of the gearbox to define the progressivity of the (micro) pitting and the damage on the bearings.



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Location - date:

Denmark - March 2018

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