seamless Pure calcium Cored wire

1, How to improve the absorption of calcium in the steelmaking process and the principle and characteristics of calcium treatment for molten steel:

1. Production process of solid metal calcium cored wire: pure calcium rod → preheating furnace → extruder → fan cooling → strip steel placement → pole wrapping machine → rewinding machine → lower plate packaging

2. The denaturation treatment of inclusions in clean molten steel by metallic calcium, which changes the composition of molten steel, is a common smelting process in the smelting process.

3. Stabilizing the calcium content in molten steel, reducing the cost of calcium feeding line, making it more suitable for smelting refined steel products, and reducing costs have been the goals that various steel companies have been seeking. Our company's composite pure calcium processing technology meets this requirement. The basic metallurgical properties of calcium include a melting point of 850 ℃, a boiling point of 1480 ℃, a density of 1.55g/cm3, and a melting degree close to zero in molten steel,

Liquid calcium has a high affinity for oxygen and can dissolve Al2O3 inclusions. After treatment with calcium, Al2O3 in molten steel forms large liquid inclusions, which are more prone to floating. Reduced nozzle blockage caused by excessive Al2O3 in molten steel and improved its castability. After calcium treatment, Al2O3 inclusions remain spherical, improving the performance after rolling.

4. Calcium is added to the molten steel, and a portion dissolves onto the steel, becoming dissolved calcium in the steel; Part of it evaporates in the form of steam; Part of it reacts with Al2O3 inclusions or S in the steel to form impurities. During the refining and continuous casting process after this treatment, these impurities float up into the slag, and the remaining part remains in the steel as inclusions. Denaturation treatment of inclusions:

Al2O3 becomes CaO Al2O3 or CaO Al2O3 CaS; CaS becomes CaO-Al2O3-CaS. It can effectively change the fluidity of molten steel. Save the use of alloys and other deoxygenation and desulfurization materials, and save smelting costs. The condition of inclusions in molten steel is related to the amount of calcium added, the time of addition, and the speed of addition.

2, Various requirements for the addition of composite pure calcium wire:

1. Seamless calcium wire speed: unsuitable feeding speed, low calcium absorption rate, and calcium evaporation; Suitable speed, high calcium absorption rate, and less calcium evaporation.

2. Seamless pure calcium first time: After feeding the calcium line, samples are taken immediately. Impurities in the steel undergo significant changes, with the vast majority transforming into CaO Al2O3 CaS inclusions, which are small in size and nearly spherical in shape, but not completely spheroidized. In the sampling of the crystallizer, the vast majority of inclusions turn into CaO Al2O3 inclusions, forming spherical shapes with low CaS content.

3. CaO, Al2O3, CaS, and Ca are all lower than when the steel is just fed. When sampling in the billet, the inclusions change again and become CaO Al2O3 CaS inclusions, which are no longer spherical in shape and have slightly larger sizes than in the crystallizer. This is because during steel solidification, S segregation reacts with calcium to generate CaS, which aggregates with the inclusions and increases in size. The reaction between Al and O in molten steel, and the inclusion

Expanded.

4. Calcium feeding amount: The amount of CaSi wire fed should be sufficient to form 12CaO7 Al2O3 while considering loss. It is generally believed that the residual calcium content in the steel after wire feeding is 30-40ppm.

5. The calcium modification treatment using silicon calcium wire, calcium iron wire, aluminum calcium wire, and pure calcium wire will also be significantly different. The residual calcium content in molten steel is also an important indicator of calcium treatment. When the mass fraction of acid melted aluminum is 0.02-0.05%, in order to obtain liquid inclusions in this treatment, the residual calcium mass fraction is 29ppm, and the Ca/Al is 0.058-0.145. The experimental results show that

Indicating that W (Ca)/W (Al): 0.13-0.20 is optimal, with a general silicon calcium wire feed rate of 0.9kg/ton of steel.

3, The composition of inclusions and the content of S and O in steel after feeding composite pure calcium wire:

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

When S ≥ 30 * 10-4% in steel, CaS forms in the steel

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

4, The advantages of pure calcium wire:

1. Long storage time (long-term calcium storage without failure), more accurate and stable calcium content (52g/m)

2. Higher recovery rate (less calcium consumed when treating the same effect)

3. High reproducibility (small fluctuation of residual calcium) and less adsorption of harmful gases (H, N, etc.) during the feeding process result in less impurities brought in, which is more conducive to the cleanliness of molten steel.

5, When different calcium containing substances are added to steel:

1. The calcium treatment methods in molten steel include powder spraying, surface calcium wire feeding, calcium wire, alloy addition, etc.

2. Calcium wires are divided into silicon calcium wires, aluminum calcium wires, iron calcium wires, pure calcium wires, etc. Our company's composite pure calcium production line adopts bottom feeding treatment.

6, The advantages of composite pure calcium wire:

1. Using a special welding process, the calcium wire is fed at a certain speed and melted near the bottom of the ladle, resulting in a high absorption rate by the molten steel.

2. The interior of the composite pure calcium wire is solid metal calcium, with a composition of 96%. The exterior is made of 08 aluminum steel strip, which can ensure stable calcification after feeding the calcium wire.

3. Composite pure calcium wire does not contain silicon and is more suitable for smelting special steels such as IF steel, SPHC, SPHD, etc.

7, Process operation of composite pure calcium wire:

1. The calcium treatment methods for Yaojuxiang molten steel are: powder spraying treatment, surface feeding of core wire, deep feeding of wire gun, and less prone to wire breakage during the wire feeding process

2. A regular wire feeder can achieve this. Based on the endpoint smelting of molten steel and the deoxidation of aluminum, the amount of wire feeding is determined to achieve an appropriate aluminum calcium ratio. Adjust the pressure of the feeding wheel of the wire feeder in a timely manner to ensure that the wire feeder does not slip during the feeding process. Make the automatic counting of the wire feeder accurate and reliable, in order to grasp the reliable feeding amount. Adjust the wire feeding speed according to the size of the ladle to reduce the churning oxidation of the molten steel and facilitate smooth wire feeding.

8, Composite pure calcium line parameters:

Main ingredients: Ca ≥ 98%, diameter: 9 ± 0.25mm, addition amount: 0.35-0.4kg/ton, steel speed: 1.5-2m  s 9mm