11/02/24
A prominent Australian rail company faced a wear and corrosion issue with a traction motor shaft, particularly surrounding the bearing contact area. Over time, the bearings on the traction motor shafts would wear down the surface of the shaft, resulting in undersized worn areas.
This wear and degradation was caused by high dynamic loading and various environmental conditions experienced by the shafts. Traditional repair methods would require disassembling the shaft from the assembly, leading to increased maintenance repair times.
To restore the part to specification, the TKF9000 deposited a proprietary blend of nickel powder onto the shaft. The nickel coating restored the part to desired tolerance, and also provided a new, hard wearing surface to prevent further wear and corrosion.
Titomic’s engineers developed a unique solution to overcome this problem. First, a unique blend of nickel powder was chosen to be applied to the wear surface of the shaft, forming a hard-wearing coating. The coating was then machined to the required finish size, ensuring the restoration of the OEM design tolerance fit between the bearing and shaft.
Motor assembly mounted on TKF 9000
Before
As sprayed with Nickel
Final repair, post- machining.
The trial phase included extensive testing, such as shear lug tests, thermal cycling testing, and micro-sectional analysis, which demonstrated the effectiveness and strength of the cold spray deposition.
The TKF 9000 in Melbourne
Standing within the TKF 9000
The repair process using cold spray technology proved highly efficient and cost-effective. Titomic was able to machine and spray the shaft in a matter of hours. Since cold spray repairs do not induce a heat-affected zone, the shaft’s integrity remained intact. Additionally, this repair method could be completed without disassembling the shaft from the higher assembly, significantly reducing lead time and allowing the train to remain operational.
This solution proved to be a major breakthrough, offering a faster and more convenient alternative to traditional repair or replacement methods.
| Material | Yield strength | UTS | Elongation |
| Inconel 718 (HT1*) | 977 MPa | 1,145 MPa | 8% |
| Inconel 718 (HT2*) | 680 MPa | 1,080 MPa | 28% |
| SS 304L | 348 MPa | 645 MPa | 32% |
| Invar36 | 371 MPa | 517 MPa | 26% |
| CP Titanium HDH | 702 MPa | 800 MPa | 5.30% |
| 4330 Steel (HT1*) | 1,180 MPa | 1,300 MPa | 8% |
| 4330 Steel (HT2*) | 860 MPa | 950 MPa | 12% |
FUTURE FOCUS
Cold spray is providing a time and cost efficient method of reclaiming and maintaining parts within rail, mining, oil and gas, marine, and more. Titomic’s talented engineering team are able to quickly devise methodologies for specific part repair, and in tandem with cold spray, can often deliver effective solutions in weeks, rather than months or years.
So, if you have a challenge that may be overcome with cold spray and innovative engineering, please get in touch with the team today.
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