ENGINE FAILURE THREATENED TO AFFECT PRODUCTION AT A GOLD MINE IN GUINEA, WEST AFRICA

In-Situ Machining Solutions (UK) Ltd. responded immediately to the situation.

As a result of a website enquiry we won a contract to refurbish a crankshaft after a catastrophic failure of one of it’s Wartsila diesel generators’ 250mm crankpins/big ends at a gold mining site in West Africa.

The crankpin was so severely damaged that initial thoughts were to scrap the crankshaft in favour of purchasing a new replacement, unless a solution to repair the damage was viable. The damage was such that the induced hard effected area registered HB650 using one of our electronic hardness testers as opposed to the design value of around HB300.

Customer engineering made contact with our engineering team in Rugby UK to discuss a possible means of repair as the crankpin being induced hardened was found to have suffered a degree of bending which amounted to 0.3mm. after dial indicator checks were made on adjacent main bearings.

In-situ Machining Solutions (UK) Ltd’s. proposal to recover the crankshaft was to offer a combined machining, heat treatment and peening service without removing the crankshaft from the engine.

This technical procedure was discussed with the owner of the engine who sanctioned the repair, which was duly carried out extremely successfully. The damaged crankpin was reduced in hardness and size to satisfy the customer’s requirements. Undersize shell bearings were procured to suit the newly machined crankpin.

Carrying out this work on this remote site saved totally dismantling the engine and transporting the crankshaft to a factory for repair. It also gives control to the end user as the work is being executed, the client can see exactly what is going on and of progress being made. This particular repair saved the customer purchasing a new crankshaft saving vast amounts in monetary terms and reducing expensive overall downtime.

All work was carried out using calibrated measuring and temperature controlled equipment to the complete satisfaction of our relieved customer

The following photographs give an indication of the extensive repair work being carried out.

Heat Treatment System

The upper pictures show the heat treatment system in place.

The lower pictures indicate the on-site orbital machining work in progress and also shows indentations on the crankpin as a result of a peening exercise to eliminate the bending in the shaft caused by the engine failure.
And the finally machined crankpin indicating the 0.2 Ra µm surface finish.

Heat Treatment System
heat treatment system

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