Ladle furnace roofing is round-shaped and has a tube-type water-cooled structure. It is divided into a large LF furnace roof, a small ramming roof, an offgas exhaust hood, and is provided with an operation door and an alloy addition orifice.
Water-cooled furnace roof have the following characteristics:
1. Minimize contact between air and molten steel in the atmospheric environment
2. Hanging slag or cold steel on the edge of the ladle does not affect the performance of the furnace.
A roof for a metallurgical ladle/furnace (L.A.F) comprising a self-supporting structure of metallic pipework defining at least one flow circuit for cooling water, with a lower end having a circular peripheral flange (A), with a cylindrical body member of smaller diameter than the flange (A) located above the flange (A) (in use away from the ladle/furnace), and is provided with an end wall having a plurality of apertures each to receive, in a gas-tight manner, a carbon electrode, and an aperture for fume extraction provided in the arcuate wall of the cylindrical body member.
| Item | Typical Value / Range | Remarks |
| Roof Type | Tubular Water-Cooled (Close-packed pipes) / Panel Type | Tubular is most common for LF roofs |
| Furnace Capacity Match | 20 T ~ 300 T+ | Dimensions scale with ladle upper diameter |
| Roof Outer Diameter | 2,500 mm ~ 5,500 mm+ | Matches the ladle mouth / upper shell flange |
| Roof Height / Rise | 1,500 mm ~ 2,500 mm+ | Arch or dome height; ensures electrode clearance |
| Structure Material | Steel Pipes (e.g., 20# steel, ASTM A106) | Typically Ø60, Ø76, or Ø89 mm pipes, wall 6~10 mm |
| Delta Section (Center) | Removable Precast Refractory / Water-Cooled Copper | Area around electrode holes; suffers most arc radiation |
| Electrode Hole Qty | 3 (Standard) | Gas-tight sealing sleeves (asbestos/fiber composite) |
| Electrode Pitch Circle Dia. | 450 mm ~ 900 mm+ | Distance across the 3 electrode centers (PCD) |
| Fume Exhaust (4th Hole) | 1 x Central / Offset on Roof Dome | Connected to the Fume Treatment Plant (FTP) |
| Alloy Addition Port | 1 ~ 2 Chutes / Openings | For adding ferroalloys or fluxes (sometimes on side) |
| Operation / Peep Door | 1 x Hinged or Sliding Door | For visual inspection or manual intervention |
| Cooling Water Flow | 50 ~ 300+ m³/h | Total flow for the roof structure |
| Cooling Water Pressure | 0.4 ~ 0.8 MPa (4~8 bar) | Inlet pressure; return is usually open or low pressure |
| Water Temp. Rise (ΔT) | ≤ 15 ~ 20 °C | Across the roof circuit |
| Lifting Stroke / Travel | 400 mm ~ 800 mm | Hydraulic cylinder lift to clear the ladle top |
| Sealing Method | Sand Seal / Flexible Ceramic Fiber Gasket | To minimize air ingress and fume leakage |
| Overall Dry Weight | 3,000 kg ~ 25,000 kg+ | Depends on size and pipe thickness |
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