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1. Production process of solid-core metal calcium-clad wire: pure calcium rod preheating furnace extruder fan cooling strip placement cladding machine rewinder disc packing

2. The modification of inclusions in clean molten steel by calcium metal and the change of composition of molten steel are normal smelting processes in the smelting process.

3. Stabilizing the calcium content in molten steel, reducing the cost of feeding calcium wire, better applying to smelting refined steel products, and reducing the cost are the goals that every steel enterprise has been seeking. The processing technology of compound pure calcium wire in our company meets this requirement. The basic metallurgical properties of calcium are melting point 850 C, boiling point 1480 C and density 1.55g/cm3. The melting degree of calcium in molten steel is close to zero.

The liquid calcium can dissolve Al2O3 inclusions. Al2O3 and calcium in molten steel form large liquid inclusions, which are easier to float. The blockage of nozzle caused by excessive Al2O3 in molten steel is reduced and the pourability of molten steel is improved. After calcium treatment, the inclusions of Al2O3 remained spherical and the properties of rolled Al2O3 were improved.

4. Calcium is added to molten steel, and part of it dissolves into molten steel to dissolve calcium; part evaporates in the form of steam; part reacts with Al2O3 inclusion or S in steel to form impurities, which float into slag during refining and continuous casting after treatment, and the remaining part remains in steel to become inclusions. Things. Denaturation of inclusions:

Al2O3 becomes CaO-Al2O3 or CaO-Al2O3-CaS; CaS becomes CaO-Al2O3-CaS. It can effectively change the fluidity of molten steel. The use of alloys and other deoxidizers and desulfurizers can be saved, and the smelting cost can be saved. The inclusions in molten steel are related to the amount of calcium added, the adding time and the adding speed.

2. Various requirements for the addition of composite pure calcium wires:

1. Seamless Ca wire speed: unsuitable feeding speed, low Ca absorption rate, Ca evaporation; suitable speed, high Ca absorption rate, less Ca evaporation.

2. Seamless Pure Calcium Prior Time: After feeding calcium wire, the impurities in steel change obviously, most of them are converted into CaO-Al2O3-CaS inclusions, which are small in size and nearly spherical in shape, but not completely spheroidized. Sampling in the mould, most of the inclusions become CaO-Al2O3 inclusions, spherical, low CaS content.

3. CaO, Al2O3, CaS and Ca are all lower than those at the beginning of wire feeding. When the inclusions are sampled in the billet, they change again and become CaO-Al2O3-CaS inclusions. The shape is no longer spherical and the size is slightly larger than that in the crystallizer. This is because S segregation occurs when the steel solidifies and reacts with calcium to form CaS, which aggregates with the inclusions and enlarges its size. Reaction of Al and O in molten steel with inclusions

Inflated.

4. Calcium feeding quantity: CaSi wire feeding quantity should be enough to form 12CaO7 Al2O3 and loss should be considered. It is generally considered that residual calcium content in steel after wire feeding is 30-40 ppm.

5. Calcium denaturation treatments with silica-calcium wire, calcium-iron wire, aluminium-calcium wire and pure calcium wire are also quite different. The residual calcium content in molten steel is also an important index of calcium treatment. When the mass fraction of molten aluminium is 0.02-0.05%, the residual calcium content in molten steel is 29 ppm and Ca/Al is 0.058-0.145.

The results show that W(Ca)/W(Al):0.13-0.20 is the best, and 0.9kg/ton steel is fed with normal silicon-calcium wire.

3. Composition of inclusions and content of S and O in steel after feeding compound pure calcium wire:

1. S < 10*10-4% in steel: CaO-Al2O3-CaS or CaO-Al2O3-CaS-MgO formed in steel.

CaS is formed in steel when S is more than 30*10-4%.

2. If the original content of O in steel is high, the CaO formed by Ca and O should be selected at the end of de-O treatment. Ordinary calcium wire can only be fed to a certain depth below the molten steel level. Our company's composite pure calcium wire can reach the bottom of molten steel.

4. Advantages of pure calcium wire:

1. Long storage time (long-term storage of calcium does not fail) is more accurate, more stable calcium content (52g/m)

2. Higher recovery rate (less calcium consumed in the same treatment effect)

3. Higher reproducibility (less fluctuation of residual calcium) and less absorption of harmful gases (H, N, etc.) in the process of wire feeding bring less impurities, which is more conducive to the cleanliness of molten steel.