Blog

Home page

A Brief introduction to silicon-based ramming mass used in foundries

2025-10-30

Acidic ramming mass with a silica content >90% are the main lining material for medium-frequency induction furnaces. Their refractoriness of 1650–1850℃ is sufficient to resist the thermal erosion of molten iron and steel, while their high silica content effectively resists acidic corrosion from molten slag. Modern formulations, by adding fused silica (15–40%) and pre-phase-change silica, significantly reduce the thermal expansion defects of traditional silica sand, achieving stability of "no cracking during cold furnace start-up and no collapse under thermal shock," making them particularly suitable for intermittent casting production cycles.

1. Application Scenarios:

1. Smelting of gray cast iron/ductile iron and high-manganese carbon steel. Applications include:

Furnace bottom load-bearing layer: rammed in layers to a thickness of 280mm, bearing the static pressure of molten metal and the impact of charging;

Furnace wall working lining: a uniform lining of 110–120mm, directly in contact with molten metal and slag line;

Taphead/furnace nozzle: locally thickened to enhance erosion resistance, requiring maintenance with specialized repair material;

2. Life cycle and maintenance strategy: from annual inspection to daily maintenance

Long-lasting main lining: integrally rammed during new construction or major overhaul, with a target life of 1–3 years (approximately 300–600 furnace cycles), synchronized with the electric furnace overhaul cycle;

Local hot repair: for slag line erosion or cracks, using the same repair material to fill once a week to monthly, extending continuous operation time;

Failure warning signs: when the furnace lining thickness is <65mm or longitudinal through-cracks appear, the furnace must be shut down and rebuilt to avoid furnace penetration accidents.

3. Construction Process

Layered Compaction:

Each layer of filler at the furnace bottom should be ≤100mm, and at the furnace wall ≤60mm. 4-6 people should work in shifts to compact the filler, rotating every 30 minutes to avoid uneven density.

Precise Furnace Drying and Sintering:

Three-stage temperature control: 600℃ for dehydration (4h), 900-1200℃ for semi-sintering (6h), and ≥1500℃ for full sintering, with a rate ≤100℃/h to prevent cracking.

Moisture Control:

Paper bagged materials must be stored in a dry warehouse (≤1 year). Moisture absorption will reduce sintering strength by more than 30%.

Refractory materials for electric furnaces

A Brief Introduction of Ladle Ramming Mass

Real-time Information

■

How can porous plug improve the efficiency of steel melting ?

—

2025-12-11