A: Liquid metal. B: Solidified metal. C: Slag. D: Water-cooled copper plates. E: Refractory material.
Equipment and Process
• The steel is taken poured into water cooled vertical cooper moulds, which is 450 to 750 mm long. • Before starting the casting a dummy starter bar （引锭杆 ） is kept in the moulds bottom. • After starting the casting process as the metal level rises in the mould to a desirable height, the starter bar is withdrawn at a rate equal to the steel pouring rate.
Mold
• The working surface of the copper face is often plated镀 with chromium铬 or nickel to provide a harder working surface, and to avoid copper pickup on the surface of the cast strand • Friction between the shell and mold is reduced through the use of mold lubricants such as oils or powdered fluxes粉剂. • Mold oscillation（震荡）is necessary to minimize friction and sticking of the solidifying shell, and avoid shell tearing, and liquid steel breakouts, which can wreak havoc造成严重破坏 on equipment and machine downtime due to clean up and repairs. • Oscillation is achieved either hydraulically or via motor-driven cams or levers which support and reciprocate往复运动 (or oscillate) the mold.
Equipment and Process
• The skin formed in the mould is about 10 to 25 mm in thickness and is further solidified by intensive cooling with water spays as casting processes. • Feeds liquid steel continuously into a short, water-cooled vertical copper mold and, at the same time, continuously withdraws the frozen shell, including the liquid steel it contains.
As unbending occurs, the solid shell outer radius外径 is under tension拉力, while the inner radius is under compression. The resulting strain is dictated by the arc radius along with the mechanical properties of the cast steel grade. If the strain along the outer radius is excessive, cracks could occur, seriously affecting the quality of the steel. These strains are typically minimized by incorporating合并 a multi-point unbending process, in which the radii半径 become progressively larger in order to gradually straighten the product into the horizontal plane.
Continuous Cast Shapes
Bloom or Billet Rounds
Slab(variable thickness)
Beam blank
Dummy Bar(引锭杆)
• Functions: • to close off the base of the mould. • Metal is poured into the mould and withdrawn with the dummy bar once it solidifies.
Equipment and Process
1: Ladle. 2: Stopper. 3: Tundish浇铸盘. 4: Shroud保护罩. 5: Mold. 6: Roll support 轧辊支架. 7: Turning zone转折带. 8: Shroud. 9: Bath level炉浴面. 10: Meniscus弯液面. 11: Withdrawal unit 提取单元. 12: Slab.板坯
Bending and Straightening
Curved Section of MultiStraightener Strand Beam Blank Caster Withdrawal Units for prior to Unbending Strand Unbending
After straighten process
– Distribute liquid steel to the molds – Enhances oxide inclusion separation – Provides a continuous、constant and stable flow of liquid steel to the mold during ladle exchanges
Introduction
• Generally the starting point of any structural steel product is the ingot, which is subsequently rolled through number of mills before a final product. • Continuous casting has changed that scenario by directly casting billet(坯料), bloom(钢坯), and slab(板坯) without going through the rolling process and this process is fast and also economical.
The dummy bar should be corresponded to the casting path
Dummy Bar
Rigid type
Chain structure : more flexible to be corresponded to the casting path
Tundish
Mold
• Stucture:ope n-ended box structure, containing a water-cooled inner lining fabricated from a high purity copper alloy.
Mold
• Function:to establish a solid shell sufficient in strength to contain its liquid core.
Introduction
• Continuous casting is the process whereby molten metal is solidified into a "semifinished " billet, bloom, or slab for subsequent rolling in the finishing mills(精 轧机). • This process is used most frequently to cast steel. Aluminums and copper are also continuously cast.ters
Continuous Cast Shapes
Depending on the product end-use, various shapes are cast .In recent years, the melting/casting/rolling processes have been linked while casting a shape that substantially conforms to the finished product. The Near-NetShape cast section has most commonly been applied to Beams and Flat Rolled products, and results in a highly efficient operation.