An Industrial Member asked TWI if it could refurbish three worn shafts from industrial rotating equipment. The one chosen was laser cladding using direct laser metal deposition.
The repair was to involve initial preparation of the shafts to create a satisfactory surface followed by the addition of material using the Trumpf DMD505 deposition system installed at TWI'S Rotherham base.
One of the three shafts supplied was used for experimenting with process parameters. The other two shafts were intended for re-use following successful refurbishment and subsequent post deposition machining.
TWI's immediate objectives were; to procure, install and commission additional equipment for the job; to produce and analyse two individual cladded batch test pieces; and to refurbish the two shafts supplied using established procedures from previous experimental work. The deposit geometry was to be in accordance with a supplied drawing.
The deposition job involved using TWI's Trumpf DMD 505 laser deposition system and included three sub systems;
- A Fraunhofer ILT side-feed powder delivery nozzle.
- A Sulzer Metco type single 10-C powder feeder
- A rotary positioner
All the deposition tasks were performed onto cylindrical substrate articles of a known material. Following experimentation TWI produce a welding procedure specification for the clients' approval.
TWI was able to conclude to the client's satisfaction that the additional equipment was successfully installed and commissioned. Secondly, that the combination of the laser deposition system, its parameters and surface preparation procedures, all developed in a previous project, were shown to meet the client's acceptance criteria.
Two individual batch test pieces were laser clad and after metallurgical assessment were concluded to have met the laser cladding defect acceptance criteria. Lastly two shafts were successfully clad using the approved weld procedure developed by TWI and the deposit geometry was in accordance with the client's supplied drawing.
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