Ramming mass for induction furnaces is a type of monolithic refractory material used for the lining of induction furnaces. It is applied through forceful ramming to form a dense and robust lining at high temperatures, protecting the furnace shell and resisting erosion from molten metal.
Based on the acidity or alkalinity of the slag, ramming mass is mainly classified into three categories:
Acidic: Primarily composed of high-purity quartz sand, suitable for acidic slag environments, low cost, and most widely used;
Neutral: Primarily composed of corundum, spinel, and high-alumina bauxite, offering good thermal shock resistance and slag resistance;
Alkaline: Primarily composed of magnesia and dolomite, suitable for alkaline smelting, such as high-manganese steel and stainless steel.
High-quality ramming mix must possess the following characteristics: ① High refractoriness (≥1700℃); ② Good thermal shock resistance to withstand sudden temperature changes from frequent furnace start-ups and shutdowns; ③ Excellent resistance to slag and molten metal penetration; ④ High bulk density and low porosity; ⑤ Uniform transition between the sintered and semi-sintered layers after construction, preventing spalling.
During construction, use pneumatic or manual ramming tools to ram the mix in layers to ensure compaction. The sintering process must be strictly controlled according to the temperature rise curve to achieve internal ceramic bonding. During use, the furnace lining thickness must be checked regularly to prevent localized thinning that could lead to furnace penetration accidents.