Any interruption due to a component failure leads to unforeseen expenses and production interruptions. Most of the failures are linked to issues where the material is subject to specific loading and environmental conditions. OCAS is involved in analysing failures, proposing adequate repair methods and remedy actions to prevent failures from occurring again. We have assembled a multi-disciplinary task force to address the rising demand for services related to failure analysis, engineering critical assessment, fit-for-purpose analysis and asset integrity and reliability services. Discover this recent case.
Problem: Malfunction of wire rope sheave
It was seen that the sheave was no longer in the correct position (out of plane). Visual inspection revealed partial/complete fracture at multiple positions at one of the pulley wheels.
Approach
Failed areas were sampled for analysis by optical and electron microscopy. Cross sections were made, and hardness was checked in order to identify the failure mechanism
Conclusions
From the investigation following possible factors were found to have influenced the failure mechanism
1. Casting defects
2. Decarburized surface, confirmed by lower hardness readings near surface compared to bulk
3. Significant lower wall thickness groove
Almost all failures showed typical signs of fatigue, initiated by casting defects, facilitated by the decarburized surface.
Recommendation
Replace damaged pulley wheels and inspect all remaining sheave cranes.
More cases
Browse these related cases and learn how OCAS can help.
- Failure analysis
- Evaluate whether flawed structures are still fit-for-purpose
- Preventing failure
“Our dedicated OCAS team offers a versatile skill set in welding, corrosion, fatigue, wear and fracture. We are confident we can add value by supporting our customers in their asset reliability and structural integrity efforts.”
