Rapid Emergency Reseal Prevents Extended Hot Strip Mill Downtime
Introduction
A hot strip mill HAGC cylinder failed with no spare available. The cylinder showed damage on both rod and bore, and surface imperfections remained even after minor hand polishing; full refurbishment was not possible within the timeline the mill required. Compounding the problem, the standard PTFE seal could not be sourced for same-day delivery. Left unresolved, the mill faced several days of unplanned downtime and potential losses worth hundreds of thousands of dollars.
Challenge
To design and deliver, within a single day, a sealing solution for a damaged HAGC cylinder rod and bore, where standard PTFE seals could not be sourced in time and full refurbishment was not achievable before the mill needed to restart.
Solution
System Seals engineered an emergency sealing strategy centered on a 72 Shore D MP07 rod seal, selected for improved extrusion resistance suited to imperfect bore conditions, paired with an MP07 318-style wiper in a high-durometer polyurethane chosen for superior abrasion resistance on the damaged rod surface. The complete turnaround, designed initially as a temporary repair, was executed in one day. Measured profile dimensions on both components confirmed the seals were within original tolerance.
Result
The cylinder ran a full year in service before it was removed for inspection. No active leakage was observed, only a slight oil film on the rod surface, and wear on both the rod seal and wiper was minimal. What began as a same-day emergency repair was validated as a long-term reliability solution, confirming the MP07 polyurethane system for extreme HAGC environments and proving its compatibility with damaged surfaces in production, without requiring further mill downtime.
