Remelting slag for electroslag remelting plate blank and manufacturing method thereof

Abstract

The invention relates to remelting slag for an electroslag remelting plate blank and a manufacturing method thereof. The manufacturing method is characterized by comprising the following steps of: mixing 28 to 30 weight percent of lime, 30 to 32 weight percent of aluminum oxide, 39 to 41 weight percent of fluorite and 1 to 3 weight percent of magnesium oxide uniformly, premelting at the high temperature of 1,200 and 1,550 DEG C, and cooling and crushing to form granules of between 3 and 20 millimeters. The premolten remelting slag comprises the following chemical ingredients in percentage by weight: 39 to 41 percent of CaF2, 8 to 30 percent of CaO2, 32 to 34 percent of Al2O3, less than or equal to 0.01 percent of SiO2, less than or equal to 0.01 percent of P2O5, less than or equal to 0.01 percent of S and less than or equal to 0.01 percent of total carbon, wherein CaO / Al2O3 is 0.9 to 1.0. The invention has the advantages that: 1) the chemical ingredients of a remelting slag system in the process of remelting the plate blank are not deteriorated, and the slag system is stable relatively; and 2) the content of the fluorite in the components is low, so the pollution of fluorine on environment is reduced.

Description

technical field [0001] The invention relates to the field of iron and steel metallurgy electroslag remelting technology, in particular to a remelting slag used for electroslag remelting slabs and a manufacturing method thereof. Background technique [0002] There is a big difference between electroslag remelted 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, which are basically within 10t. The remelting time is relatively Short, but the size of the section of the electroslag remelting slab varies greatly, and the ratio of width to thickness can reach 5-10. Compared with the round billet, the filling ratio is small, and the overall ingot shape is too large, basically above 10t, even as high as 200t , the remelting time is relatively long, even as long as 100h, and the slag system deteriorates seriously after long-time smelting. Therefore, the requ...

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Problems solved by technology

[0002] There is a big difference between electroslag remelted 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, which are basically within 10t. The remelting time is relatively Short, but the size of the section of the electroslag remelting slab varies greatly, and the ratio of width to thickness can reach 5-10. Compared with the round billet, the filling ratio is small, and the overall ingot shape is too large, basically above 10t, even as high as 200t , the remelting time is relatively long, even as long as 100h, and the slag system deteriorates seriously after long-time smelting. Therefore, the requirements for the slag system of electroslag remelting slabs are more stringent, and some commonly used slag systems can no longer meet the requirements of remelting 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 composition of the slag will change in the later stage, which will affect the stability of the process. In addition, the fluorite content of the slag is high, and the fluorine pollution is serious during use.

The ternary slag system is CaF 2 -CaO-Al 2 o 3 series, CaF 2 The fluorine content is basically higher than 50%, and the high-content fluorite is seriously polluted by fluorine during use. In addition, CaO and Al in the ternary slag system 2 o 3 There is free calcium oxide in the slag series with a ratio greater than 1.0, which is not suitable for slab electroslag remelting. Other slag series CaO and Al 2 o 3 If the ratio is less than 0.90, the slag composition is no longer on the eutectic line, 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 cause serious slag grooves on the surface of the ingot

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