Electric Arc Furnace EAF bottom ramming mass Definition, Features and Application Cases

Introduction
Electric furnace bottom lining is easily eroded, cracked and sunken by high-temperature molten steel and slag during long-term steelmaking operation. Traditional cold repair requires shutting down the furnace, cooling down and long-time baking, which seriously affects production efficiency. Electric furnace bottom hot repair material is specially developed to solve this pain point. It can be constructed directly under high temperature without furnace shutdown, quickly sinter and repair furnace bottom defects, and has become the preferred refractory material for major steel mills to extend furnace life and reduce maintenance costs.
What Is Electric Furnace Bottom Hot Repair Material?
Electric furnace bottom hot repair material is a kind of magnesia-based and magnesia-calcium based monolithic refractory. It takes high-purity magnesia sand and dolomite sand as main aggregate, matched with composite binder, sintering agent and functional additives.
It is professionally used for hot-state online repairing of electric arc furnace bottom erosion pits, cracks, gaps between tapping hole bricks and furnace bottom lining. The material can be constructed normally at 800℃–1600℃ high temperature, solidifies and sinters in a short time, forms an integrated dense wear-resistant layer with the original furnace lining, and realizes rapid production resumption without stopping the furnace for cooling.
Core Features of Electric Furnace Bottom Hot Repair Material
1. Hot Construction Without Furnace Shutdown
The biggest advantage is no need to stop production and cool down. It can be constructed directly in the interval of steelmaking. After repairing, it can be put into use in 5–10 minutes, greatly reducing downtime loss and improving the operation rate of electric furnace obviously.
2. High Adhesion Strength and Good Thermal Shock Resistance
With unique composite formula, the repair material has high adhesion under high temperature, closely combined with the original magnesia furnace lining, not easy to fall off, delaminate or crack. It can withstand severe cold and heat alternation in steelmaking process and maintain stable structural strength for a long time.
3. Excellent Slag Erosion and Molten Steel Scouring Resistance
High magnesium oxide formula effectively resists alkaline slag corrosion and molten steel scouring. The internal structure is dense with low porosity, which can prevent molten steel and slag from penetrating into the furnace bottom lining, greatly prolonging the service life of furnace bottom.
4. Convenient Construction and Wide Adaptability
It is powder or plastic shape, no special construction equipment required. Manual tamping can complete filling and repairing of pits, cracks and narrow gaps. It is suitable for 10t–150t various ultra-high power electric arc furnaces, applicable to furnace bottom, furnace slope, tapping hole peripheral repair.
5. Stable Volume and Low Loss
Reasonable particle gradation ensures small shrinkage after sintering, no structural deformation. Low rebound rate during construction reduces material waste, stable physical and chemical indexes, and meets long-term continuous production requirements of steel plants.

Practical Application Cases of Electric Furnace Bottom Hot Repair Material
Case 1: 100t Ultra-High Power Electric Furnace Bottom Erosion Repair
A large iron and steel enterprise’s 100t electric arc furnace was used for carbon steel and alloy steel smelting. After continuous operation for 320 heats, local furnace bottom appeared 3–6cm deep erosion pits and radial cracks.
If adopting traditional cold repair, it needed to stop the furnace for more than 20 hours, resulting in huge production loss. The factory adopted magnesia hot repair material for electric furnace bottom, constructed under 1250℃ hot state: clean residue → fill material and tamp → natural sintering for 8 minutes to resume steelmaking.
Application effect: The repair layer is closely integrated with the original lining without falling off; the furnace bottom service life is extended by more than 160 heats; non-planned shutdown is avoided, and the comprehensive refractory cost is reduced significantly.
Case 2: 50t Electric Furnace Tapping Hole Gap Hot Repair
The gap between tapping hole sleeve brick and furnace bottom lining of a 50t electric furnace gradually expanded to 2–3cm after long-term thermal expansion and contraction, causing hidden danger of molten steel leakage.
The enterprise used calcium-magnesia hot repair material for hot filling at about 1050℃. After cleaning the gap impurities, the repair material was filled and compacted. It can be used normally after 5 minutes of sintering.
Application effect: The gap is completely sealed, no molten steel infiltration; the service life of tapping hole brick is extended, the replacement frequency is reduced, and the whole repair process does not affect the normal steelmaking rhythm.
Case 3: 30t Electric Furnace Bottom Crack Emergency Repair
Due to frequent temperature changes, a 30t industrial electric furnace bottom produced multiple penetrating cracks, resulting in abnormal furnace bottom temperature and potential safety hazards.
Using plastic electric furnace bottom hot repair material, construct under 900℃ hot state: clean crack impurities, embed the repair material into cracks and compact the surface. After sintering, the furnace returns to normal operation.
Application effect: Cracks are completely closed, heat conduction is stable, no peeling and damage of repair layer occur in subsequent production, which realizes rapid emergency repair and eliminates safety hidden troubles.

How to Choose Qualified Electric Furnace Bottom Hot Repair Material
Select corresponding magnesium content grade according to electric furnace tonnage and smelting steel type;
Prioritize products with high thermal adhesion and low rebound rate;
Focus on stable physical and chemical indexes such as volume density, high-temperature compressive strength;
Choose regular refractory manufacturers with mature application cases and on-site technical support.
Conclusion
Electric furnace bottom hot repair material is an indispensable key refractory for modern electric arc furnace steelmaking. Its advantages of hot rapid repair, no furnace shutdown, strong adhesion, slag erosion resistance and convenient construction can effectively repair furnace bottom defects, extend furnace lining service life, reduce production downtime and comprehensive use cost.
With the upgrading of steelmaking industry towards high efficiency and low consumption, high-performance electric furnace bottom hot repair material will become the mainstream choice for more steel enterprises’ furnace daily maintenance and overhaul.