Case 01 — Converter Campaign Rebuilt Around the Sections That Actually Decide Shutdown Timing

Project brief

The converter had been consuming brick as though the whole vessel aged at one speed. It did not. The mouth and upper cone opened first under repeated thermal shock, the impact zone was taking the hardest punishment from charging and blowing, and the barrel was quietly accumulating fatigue until an avoidable stop became urgent. Because the plant was still reviewing the vessel as one line item, it could see cost but not geography. What it lacked was not refractory volume. It lacked a zoned campaign narrative.

Equipment and hot zones

• Converter mouth and upper cone
• Impact zone beneath charging and oxygen-blowing paths
• Barrel and lower working lining
• Permanent lining and scheduled repair surfaces

Failure pressure profile

• Repeated thermal shock and edge opening at the mouth and cone
• Slag attack, oxidation, and exposure in upper sections
• Violent impact, washout, and localized structural loss in the impact zone
• Cycle fatigue accumulating in barrel and lower vessel positions
• Shutdown windows too narrow for a full rebuild every time the weak zone moved first

Material combination

• Zoned magnesia-carbon brick grades across mouth, cone, impact, barrel, and lower working sections
• Synthetic magnesia or equivalent structural basic brick in permanent and lower-stress support areas
• Converter water-based repair material for broad-face restoration during planned outages
• Magnesia gunning mix for rapid local recovery when the vessel had to return before a full rebuild window opened

What changed commercially

The converter stopped being purchased as a generic lining package and started being managed as a readable furnace campaign. Early-loss sections were isolated instead of buried in vessel-wide averages. Overbuilt sections could be corrected without weakening the critical zones. Repair spending moved closer to the places that actually drove stoppage. The result was a steadier campaign record, fewer emergency interventions, and repeat ordering that could be defended from operating history rather than habit.