Gunning Mass & Gunning Castable for Hot Repairs

Gunning mass is a refractory mix designed to be sprayed pneumatically onto a hot or cold lining. It is the standard tool for hot repairs of furnace working linings, allowing localised wear to be patched without taking the furnace fully out of service. Used routinely in steel ladles, EAF, BOF, cement kilns, induction furnaces and torpedo cars.

Gunning is a maintenance repair, not a full reline. A well-applied gunning patch typically extends lining life by 5–30 additional heats or days of operation, depending on duty. After multiple gunning cycles, the original brick or castable lining still needs full replacement. Best practice is scheduled gunning every 50–150 heats in steel applications.

Hot gunning is applied at 600–1400°C, the hot face is still glowing. The mass develops a strong ceramic bond by reacting with the residual lining heat. Cold gunning is applied below 200°C and relies on a hydraulic or chemical bond, typically requiring a controlled re-heat before service. Hot gunning gives stronger bonds and faster turnaround.

Silica-alumina gunning for general fireclay and high-alumina linings, basic gunning (magnesia-based) for steel ladle slag bands and EAF/BOF working linings, neutral gunning for transition zones, and specialty SiC-containing gunning for aluminium and incinerator duty. Choosing a chemistry matched to the original lining is essential, wrong chemistry causes rejection or rapid spalling.

A gunning machine (rotor or pressure-vessel type), a 25–50 m feed hose, a water supply at 4–6 bar, and operator PPE. Output is typically 2–6 t/hr for cold gunning and 1.5–4 t/hr for hot gunning. We can help you specify the right machine for your duty cycle, and supply trained gunning operators on a campaign basis.

Yes. For large steel and cement plants we offer turnkey gunning campaigns, material supply, machine, trained crew, and refractory engineer supervision. For routine maintenance we supply Calderys and CUMI gunning masses for application by your in-house team. Both options come with technical guidance on best-practice gunning thickness and frequency.

Maximum service temperature is grade-dependent. Catalog-listed values: LC Gun Mix is rated up to 1700°C; HA Gun Mix and Mag Gun Mix are rated up to 1750°C. These are typical/catalog data, not independently certified figures, request a technical datasheet for values specific to your application.

Grade selection should match your application chemistry and existing lining. Catalog-listed grades: LC Gun Mix (70-75% Al₂O₃, up to 1700°C); HA Gun Mix (80-85% Al₂O₃, up to 1750°C); Mag Gun Mix (80-85% MgO, up to 1750°C), magnesia-based and suited to basic-slag contact areas such as steel ladle slag bands per our chemistry-matching guidance above. Silica Gun Mix is also in our range, contact us for grade-specific technical data. Our engineers can help match a grade to your furnace type and repair zone.