In-Situ Repair of Worn Coal Mill Shaft Using Belzona 1111
The Challenge
A leading thermal power plant in India experienced severe wear at the bearing area of a coal mill shaft. Upon initial inspection, our service engineer observed:
- Significant material loss and surface degradation around the bearing zone
- Irregular shaft diameter causing potential misalignment with bearings
- Signs of accelerated wear likely due to abrasive conditions and operational stress
- Risk of imminent failure if left unaddressed, which would lead to extended downtime
This wear was causing operational inefficiencies and posed a risk of unexpected shaft failure, demanding urgent intervention.
Conventional Solution
The traditional repair involved welding metal buildup followed by machining to restore shaft dimensions. This method would require at least 72 hours of downtime and Involves heat input, risking shaft distortion and misalignment. Considering the time and cost constraint involved in replacement of the shaft, client choose to go with cold repair method.
The Belzona Solution
Our service engineer recommended Belzona 1111 (Super Metal). Belzona 1111 is a 2-part epoxy-based repair composite designed for metal repair and protection. It Cures rapidly, minimizing downtime and provides strong adhesion and excellent wear resistance suitable for heavy industrial use.
Application Process
The repair was carried out adhering strictly to Belzona System Leaflets:
- Thorough degreasing and cleaning of the shaft surface
- Abrasive blasting to near-white metal cleanliness (SA 2.5), ensuring optimal surface profile for adhesion
- Verification of surface roughness and cleanliness per Belzona standards
- On-site mixing and application of Belzona 1111 by our trained technicians
- Entire process completed within 12 hours, allowing fast return to service
The Outcome
- 60 hours of downtime saved compared to traditional welding and machining
- No heat input, so no risk of shaft distortion or misalignment
- Shaft restored to precise dimensions with improved wear resistance
- Avoided costly shaft replacement and extended operational disruptions
- Thermal power plant resumed production promptly with confidence in the repair’s reliability