What are the preparations before the smelting of electric arc furnace transformers

Preparation work before smelting of electric arc furnace transformer

Batching is an indispensable part of the electric arc furnace steelmaking process. Whether the batching is reasonable is related to whether the steelmaker can carry out the smelting operation normally according to the process requirements. Reasonable batching can shorten the smelting time. Attention should be paid to the batching: First, it must be correct Carry out batching calculation and accurately weigh the charging amount of the charge. 2. The size of the charge should be allocated according to the proportion to achieve the purpose of good loading and quickening. .4 is that the ingredients must meet the process requirements.

The smelting method of electric arc furnace transformer has the following requirements for the main element content in the charge:

(1) Carbon content. The carbon content in the charge should ensure that there is a sufficient amount of carbon in the oxidation period for carbon-oxygen reaction to achieve the purpose of degassing and removing inclusions. The carbon content depends on the burning loss of carbon in the melting period and the removal of carbon in the oxidation period. The carbon content and the carbon increase in the reduction period are three factors to confirm. When the charge is required to be melted, the carbon content in the steel is 0.3%-0.4% higher than the lower limit of the product standard; but the carbon content should not be too high, otherwise the oxidation time will be extended. and overheat the molten steel.

(2) Silicon content. The silicon content is generally not more than 0.8 percent of the charge, and if it is too high, it will delay the jubilation of the molten steel.

(3) Manganese content. Generally, manganese may not be considered in the batching of steel grades. Generally, the manganese content after melting is less than 0.3 percent, otherwise the jubilation of the molten pool will be delayed.

In principle, the lower the phosphorus and sulfur content, the better. Generally, after melting, the phosphorus content should be less than 0.05 percent. In order to make the charge in the furnace dense, the large, medium and small materials must be reasonably allocated when charging. Generally, the small material accounts for 15%-20%, medium material 40%-50%, large material 40%. Before feeding, the bottom of the furnace should be covered with lime that accounts for about 1.5% of the material weight, so as to make the molten slag in advance, which is conducive to the early dephosphorization , reduce the suction of molten steel and accelerate the temperature rise.

When charging, half of the small material should be put into the bottom, the upper part of the small material, and all the large material, low-carbon scrap steel and refractory furnace material should be placed in the central area of ​​the furnace. On the top and 4 weeks of the large material, put the small material on the top of the large material. The electrode blocks used in the batching should be smashed into about 50mm-100mm and installed in the lower layer of the charge.

In short, the fabric should be: dense at the bottom, loose at the top, high in the center, low at 4 weeks, and no large material at the door of the furnace; make it fast through the well and do not build bridges.