An Ultimate Product to Metal/Steel Foundries Worldwide From PreRish Tri
Continuous casting (CC) mould powder is used primarily to facilitate the passage of steel through the mould. It is also known by names such as casting powder, mould powder and mould flux. CC mould powder plays an important role in the continuous casting of liquid steels. It is one of the most critical and influential factors for smooth continuous casting of the liquid steel. CC mould powder is sprayed at the top of the liquid steel in the mould either manually or by automatic feeders. CC mould powder after additions in the mould
- Heat up and loose some carbon by reaction with oxygen
- Forms a sintered layer
- Melts at a definite rate and forms sintered (mushy) and liquid layers. The liquid layer acts as a reservoir to supply liquid slag to the strand. This liquid pool should be deeper than the stroke length to ensure good lubrication.
- Forms a solid slag film through the first infiltration of liquid slag into the mould/strand gap. This slag film is glassy in nature and is typically 2 to 4 mm thick. This slag subsequently crystallizes in the high temperature regions adjacent to strand.
- Forms a liquid slag film typically of 0.1 mm thickness. This liquid slag is drawn down into the gap along the steel shell and lubricates the strand. This lubrication prevents the steel from adhering to the mould thus removing a cause of the strand break out.
Schematic diagram of different layers of mould powder after its addition in the mould is given below
Besides the function of mould lubrication, CC mould powder has to perform some more basic functions. These other basic functions are enumerated below.
- Thermally insulate the liquid steel meniscus for preventing premature solidification. Improved thermal insulation increases the temperature in the meniscus region of the liquid steel which helps to make oscillation marks less severe and can reduce sub surface defects such as pin hole.
- CC mould powder forms three layers namely solid layer, sintered layer and liquid layer. This three layer system acts as a protective barrier and protects the liquid steel meniscus in the mould from reacting with atmospheric gases
- Absorb inclusions (such as Al2O3 and TiO2) from the liquid steel
- Provide uniform heat transfer across the infiltrated slag layer between the steel strand and the mould
PreRish Tri is a Premium Manufacturer of Flux Continuous Casting Mould Powder (Foundry Grade)
- Casting Powder forms a good lubricating film on the surface of mould not allowing solidifying metal adhesion to the mould.
- Casting Powder provides easy and fast solidification of metal by providing high rate heat removal from metal.
- Casting Powder gives very good performance at elevated temperatures with the aid of its well selected additives.
- Casting Powder increases the quality of metal surface.
- Casting Powder is cheaper than Rapeseed/Casting Oil.
- CaO % : 30 – 35
- SiO2 % : 33 – 40
- Al2O3 % : 8 – 10
- Na2O/K2O % : 4 – 6
- C free% : 5 – 7
Casting Powder contains low melting constituents that instantly generate liquid slag, which penetrates into the gap between the mould and the solidifying shell of the billet. Casting Powder is added in small amounts and continuously over the casting duration. The melting of the Casting Powder occurs slowly in layers. Hence, the top surface of the liquid metal in the billet / slab / bloom always remains protected from the atmosphere.
Traditionally Casting Powder is used for bloom and slab casting. Now, it is used for billet (open) casting also as an alternative to mould oil for some plants.
DSP mould and SEN
Sample overview showing the steel layer (1), the slag pool (2) and the powder layer (3)
Powder consumption at the DSP: Black line: measured (plant) data. Dotted line: modified-Wolf equation. Dashed line: equation for DSP caster