What Converter Repair & Maintenance Actually Involves
Steel plant converters — BOF, AOD, and similar vessels — operate in one of the most severe environments in heavy industry. They rotate through charging, blowing, and tapping positions thousands of times over their service life, carrying vessels that weigh hundreds of tonnes at high temperature. The trunnion ring and its associated bearings, shafts, and drives absorb every one of those load cycles.
Over time, trunnion ring bores wear, journal surfaces lose their geometry, and drive housings develop alignment drift that the original commissioning never accounted for. When this happens, the practical repair is almost never to remove the converter — the civil and logistical requirements for that are enormous. Repair and maintenance of converter components in-situ is the standard approach: machining trunnion bores, journals, and drive housings in place while the converter is on its trunnion ring.
We carry portable line boring, journal grinding, and alignment equipment to the converter and carry out the repair without removing the vessel from the steelmaking bay.
What We Repair on Converters
- Trunnion ring bore machining — re-boring worn trunnion ring bores to correct diameter and roundness for new bearing fits.
- Trunnion shaft journal grinding — in-situ grinding of trunnion shaft journals to restore correct diameter, roundness, and surface finish.
- Drive housing bore machining — correcting worn or oval bores in the drive housings that locate the gearbox and coupling.
- Bearing housing face machining — restoring flatness and perpendicularity of bearing housing faces to prevent secondary misalignment.
- Alignment verification — laser alignment of the trunnion shaft axis to drive shaft and foundation references.
- Dimensional survey and reporting — full CMM and portable measurement survey of all critical converter geometry before and after repair.
Why Converter Repair Is Always Done In-Situ
Converter removal is a major civil engineering operation involving structure modification, specialist heavy lift, and weeks of preparation. For planned maintenance shutdowns, which are measured in days not weeks, removal is simply not an option — the repair has to happen with the converter on the trunnion ring.
In-situ repair also preserves the converter's relationship to the steelmaking bay infrastructure — the lance system, the charging crane path, and the taphole alignment — all of which are calibrated around the converter's installed position.
Where This Matters Most
- BOF (Basic Oxygen Furnace) converters
- AOD (Argon Oxygen Decarburisation) vessels
- Electric arc furnace tilting mechanisms
- Ladle turret and ladle car trunnions
Our Process for Converter Repair & Maintenance
Dimensional Survey
We survey the trunnion bores, shaft journals, housing faces, and alignment references to establish the full scope of wear and deviation.
Repair Plan
We define what to machine and in what sequence, confirm undersize and tolerance targets, and agree the plan with the steelplant engineering team.
In-Situ Machining
Bores are re-machined, journals are ground, and faces are corrected. Each step is measured in-process to confirm the target is reached.
Alignment & Report
Laser alignment of the repaired assembly is carried out and a full dimensional report issued before the converter returns to service.
Industries We Serve
Converter Repair: Common Questions
Can trunnion ring bores be machined accurately with the converter in place?
Yes. Line boring bars are set up spanning the trunnion ring from both sides, referenced to the existing bore centreline, and bore to the new bearing fit diameter. This is standard practice on converters and similar heavy rotating vessels.
How long does a converter trunnion repair typically take during a shutdown?
A trunnion bore machining and journal grinding job typically runs five to ten days on site depending on the extent of wear and the converter size. We confirm the estimate after the initial dimensional survey.
Do you coordinate with the steelplant's planned maintenance schedule?
Yes — all our converter repair work is planned around the plant's defined shutdown window. We mobilise in advance, set up boring equipment before shutdown begins where possible, and work continuously through the shutdown to complete within the agreed window.
Dynamics Engineering provides repair and maintenance of converters on-site across Pune, Maharashtra, and PAN India. If your converter trunnion bores, journals, or drive housings need attention, contact us for an assessment during your next planned shutdown.
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