1, deoxygenation. AD powder contains pure aluminum, which can replace SiC and some aluminum wires in refining furnace, and can also be tapped in converter.
When in use, oxygen can be removed to below 40ppm.
2. Promote desulfurization. AD powder contains a lot of Al2O3, which is quite different from Al2O3 in bauxite. advertisement
After special treatment, Al2O3 in the powder is in a critical state with strong activity, which is easy to combine with CaO to form calcium aluminate slag system with high sulfur capacity. In addition, due to the existence of aluminum, AD powder reduces the activity of oxygen, which is more conducive to the removal of sulfur from molten steel (iron). The desulfurizer made of AD powder and other materials has good desulfurization effect and low cost in the pretreatment of hot metal.
3. foaming. In the refining process of AD powder, AD powder can be foamed within one minute; Components such as CaO, Al2O3 and MgO can be retained.
Appropriate high-temperature fluidity and surface tension, so the submerged arc performance is good, the heating speed is fast, and the electrode power consumption is greatly reduced. The foaming mechanism of AD powder is mainly that the carbon in the electrode and a small amount of carbon in AD powder react with FeO, MnO and SiO2 _ 2 in the slag at high temperature to generate bubbles such as CO. However, carbonate such as BaCO3 and BAC _ O3 is added. Because they are completely decomposed at about 900℃, the refining temperature above 1600℃ is limited.
4, AD powder to remove inclusions in steel. The reducing slag system, mainly calcium aluminate, is due to its viscosity and surface at high refining temperature.
Tension, easy to absorb calcium oxide in steel, especially а- Al2O3 and other inclusions in LF refining process, with the stirring of argon at the bottom, the inclusions in steel float up and are absorbed by AD powder. According to the different refining time, the total amount of inclusions in steel can generally be reduced by more than 50%, and the effect of purifying molten steel is very obvious, which is suitable for producing high-quality steel. In addition, the effect of using AD powder as white slag is also very good.
AD powder series products have been patented in China and Japan. The following are some physical and chemical indexes of AD powder series products:
Product: advertising powder–15
Composition: metal Al:13 ~18% Al2O3: 60 ~ 75% MgO: < 3% SiO2: <; 8%
H2O:& lt； 0.5% S:& lt； 0.05% P:& lt； 0.05%
Product: advertising powder -20
Composition: metal Al:18 ~ 23% Al2O3: 55 ~ 70% MgO:
H2O:& lt； 0.5% S:& lt； 0.05% P:& lt； 0.05%
Product: advertising powder -30
Composition: metallic aluminum: 28-33% alumina: 45-60% magnesia:
H2O:& lt； 0.5% S:& lt； 0.05% P:& lt； 0.05%