Electro slag remelting slag and manufacturing method thereof

Abstract

The invention provides electro slag remelting slag and a manufacturing method thereof. The remelting slag comprises the following components: 30-35% of CaO, 30-35% of Al2O3, 28-38% of CaF2 and 0.1-5% of MgO, wherein CaO / Al2O3=0.98-1.02, SiO2<=0.01%, P2O5<=0.01%, S<=0.01% and TC<=0.01%. The manufacturing method of the electro slag remelting slag comprises the following steps of: crushing raw materials including lime, alumina powder, fluorite and magnesium oxide to be less than or equal to 200 meshes; then, burdening, and uniformly mixing; next, premelting at the high temperature of 1200-1550 DEG C; and after slag is cooled, processing the slag into granules with the size of less than or equal to 40mm. The remelting slag provided by the invention is reasonable in component, simple in manufacturing process, low in fluorite content in raw materials and beneficial to the reduction of fluorine pollution. The slag is stable in the using process, stable in chemical component during remelting, smooth in ingot surface and good in energy saving and consumption reducing effects.

Description

technical field [0001] The invention belongs to the technical field of steelmaking, and in particular relates to electroslag remelting slag for electroslag remelting slabs and a manufacturing method thereof. Background technique [0002] There is a big difference between electroslag remelted thick slabs and remelted round billets and special-shaped billets. Electroslag remelted round billets have uniform cross-sections, large filling ratios, and small overall ingot shapes. It is relatively short, but the cross-sectional size of electroslag remelted thick slabs varies greatly, and the ratio of width and thickness can reach 5-20. Compared with round billets, the filling ratio is small, and the overall ingot shape is relatively large, basically above 10t, or even As high as 200t, the remelting time is relatively long, even as long as 100h. Therefore, the requirements for the slag system of electroslag remelting slabs are more stringent, and some commonly used slag systems can n...

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Problems solved by technology

[0002] There is a big difference between electroslag remelted thick slabs and remelted round billets and special-shaped billets. Electroslag remelted round billets have uniform cross-sections, large filling ratios, and small overall ingot shapes. It is relatively short, but the cross-sectional size of electroslag remelted thick slabs varies greatly, and the ratio of width and thickness can reach 5-20. Compared with round billets, the filling ratio is small, and the overall ingot shape is relatively large, basically above 10t, or even As high as 200t, the remelting time is relatively long, even as long as 100h. Therefore, the requirements for slag system of electroslag remelted slabs are more stringent, and some commonly used slag systems can no longer meet the requirements of remelting thick slabs

[0003] Commonly used electroslag remelting slag systems are binary slag system and ternary slag system. The binary slag system is the commonly used "37" slag system: 70% CaF 2 , 30% Al 2 o 3 , the composition of the "Sanqi" slag is not at the eutectic point, and there is a liquidation problem in the cooling process of the slag, which leads to Al in the first cooled slag skin 2 o 3 If the content is too high, the slag composition will change in the later stage, which will affect the process stability, and the electrical conductivity of the slag will increase in the later stage of melting and casting, which will reduce the thermal efficiency of melting and casting and waste a lot of electric energy

In addition, the fluorite content of the slag is relatively high, and the fluorine pollution is serious during use.

The currently used ternary slag system is CaF2-CaO-Al 2 o 3 series, CaF 2 The content is basically higher than 50%, and the fluorine pollution is serious during the use of high-content fluorite; the slag is a kind of CaO and Al 2 o 3 If the ratio is greater than 1.0, there is free calcium oxide in the slag system, which is not suitable for electroslag remelting of thick slabs. Al 2 o 3 As the content decreases, the conductivity of heavy slag increases, the power consumption is high, and the applicable cost is increased; another kind of CaO and Al 2 o 3 ratio is less than 0.90, although Al 2 o 3 As the content increases, the electrical conductivity of remelting slag decreases, and the power consumption of remelting decreases, but the slag composition is no longer on the eutectic line, and there is a liquidation problem in the slag cooling process, resulting in Al in the first cooled slag skin 2 o 3 If the content is too high, the later slag Al 2 o 3 The content is reduced, and the composition of the heavy slag changes, thus affecting the process stability

[0004] In short, the existing heavy slag has high fluorite content, serious fluorine pollution, deterioration of the slag system during use, serious slag grooves on the surface of the ingot, and serious burning loss of chemical components

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