SU1084105A1 - Method of casting ferroalloys - Google Patents

Abstract

1. A method of ferroalloying, including pouring liquid melt into a separation device, separating metal from slag, pouring metal into molds and cooling with layer-by-layer crystallization of ingots, characterized in that, in order to reduce the consumption of molds and increase the yield, the casting is carried out at metal at 50-150 ° C above the temperature of the {Liquid line of the liquidus with a speed of 0.3-1.8 t / min, and cooling of each metal layer until complete crystallization is carried out at a speed of 5-20 ° C / min. 2. The method according to item 1, about tl and h and yushchi with the fact that after filling the first layer the surface of the liquid metal F tal is covered with a low-melting slag with the mixture I forming.

Description

thirty

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The invention relates to ferrous metallurgy, namely the production of ferroalloys. There is a method of casting ferroalloys in massive flat steel or cast iron molds. During crystallization, rectangular ingots with a thickness of 100-250 mm are formed, which are exhausted or knocked out of the glaze with the help of lifting and transporting devices and then crushed manually or mechanically, ij. The disadvantages of this method are the incoherent speed of the casting and cooling of the metal, and therefore; ingot strength and fragility, the ability to weld ingots to molds, in connection with which the removal of ingots is associated with the use of heavy manual labor or significant dynamic (impact) loads on molds / considerable time indebtedness of hoisting-and-transport mechanisms for operation x metal casting and removal of ingots from molds / high specific consumption of molds due to the impact of a jet of liquid metal and impact loads .; debt of crushing equipment or the use of non-productive manual labor; significant losses of metal in casting and crushing ingots in the form of fines and dust. There is also known a method of casting ferroalloys using conveyor-type filling machines equipped with small molds (molds). The known method makes it possible to control the CAPACITY of metal casting and cooling of ingots by means of forced water spraying of the surface and to simplify crushing operations of jSj ingots. the oxidation of the surface of the casting due to direct exposure to water and the atmosphere; uneven cooling of the ingots over the cross section, in connection with which the shrinkage shells and voids are formed in the ingot, contributing to an increase in the yield of fines during the crushing of the ingots, as well as significant depreciation costs for the operation of casting machines. The closest to the technical means proposed is a method of casting ferroalloys, including melting drains. in the separation device, the separation of metal from slag, the filling of molds with metal, and layer-by-layer crystallization of ingotsSZ. The disadvantage of the method is the failure of the alloy casting and ingot cooling modes, and therefore the uncontrollability of the process can lead either to increased oxidation of the alloy, or to weldability of metal layers, or to uneven crystallization, the occurrence of temperature stresses and dispersability of the alloy. The purpose of the invention is to reduce the consumption of molds and increase yield. The goal is achieved in that according to the method of casting ferroalloys, including draining the liquid melt into the separation device, separating the metal from the slag, casting the metal into molds and cooling with layer-by-layer crystallization of ingots, the casting is carried out at a metal temperature 50-150 ° C above the liquidus line temperature at a rate of 0.3-1.8 t / min, and cooling of each metal layer to complete crystallization is carried out at a speed of 5-20 ° C / min. After pouring the first layer, the surface of the liquid metal is coated with a low-melting slag-forming mixture. Modes of casting ferroalloys due to the following. A decrease in the metal temperature below the proposed limits leads to the formation of wall coverings in the ladle and metal losses, and an increase in temperature above the proposed limits does not ensure complete crystallization of the metal layer by the time of the subsequent layer casting. Reducing the casting speed below the proposed leads to the formation of wallings in the ladle and the separating device and the formation of uneven crystal layers of the flap 6c layer, which leads, in turn, to excessive grinding of the alloy upon selection of the mold. Increasing the casting speed above the proposed limits leads to a blurring of the inner surface of the molds with a metal stream, such as increased consumption, splashing and loss of the alloy. The decrease in the cooling rate below the proposed limits does not ensure complete crystallization of the metal at the time of elimination. And the subsequent melting points, and the excess of the proposed cooling rate limits leads to cracking of the ingots and an increase in the yield of fines. Example1. In an electric furnace with an aggregate of 23.0 MW, silico-manganese was smelted, and it was poured through a separating device (bank) into five steel molds with a capacity of 1.8 m each, installed. successively along the path of the copler's movement, melting in layers

to melt. The temperature of the metal decreased to 1330-1470 C, which corresponded to a value 50-150 C higher than the temperature corresponding to the liquidus line (for manganese-silicon alloys with a silicon content of 14-20%, it is 1280-1320 C, respectively), after which the alloy cast into molds, and the rate of hardening was controlled, Fick 1480

156.0

1560

1330 1550

1470 1560

1400 1530

.1410

1450 1590

1370 Example 2. The production of metal was carried out in the same electric furnace, but when it was cast in layers into molds to prevent the layers from burning each other and reducing the escape of the main elements while cooling the mixture, a low-melting mixture was formed on the first layer, for example, ferromanganese or metal slag manganese with additives go borate ore. The melting point of such a mixture was 1180-1210 s. The quality of the boundary layers when applying coatings of low-melting mixtures was significantly better, therefore, the separation of ingots was also better, the oxidation of the layers decreased. The durability of the molds was almost doubled. The introduction of the slag-forming mixture is necessary

The rate of metal casting was also fixed. After filling the molds and crystallizing the last layer, the ingots were simply tilted into the receiving containers and were shipped to the finished goods warehouse.

The table shows the parameters of the casting process and the indicators achieved.

94

The furnace maintenance is associated with a large amount of manual labor.

20 10 15 12

6 5

97 9 98 99

6.6 7.5

Introduced fusible flux on the surface of the metal layer

15

94 92

2.3 25

1.7

Layers of metal welded together

25

90

The yield of fines was above the permissible limits only after the first layer was poured, afterwards, as it was filled with subsequent layers of metal, it melts with and rises to the second, third, etc. layer. The use of the proposed method of casting ferroalloys will give a number of advantages over previously known methods ... Layering ferroalloys makes it possible to reduce, simplify and mechanize operations associated with preparing molds for metal reception, selection of ingots from molds, reduce the debt of hoisting-and-transport mechanisms, drastically reduce or completely eliminate the consumption of molds, avoid the need to coat the inner surface of 1084105

spoon nonstick material- Coating the surface of the first layer

mi., liquid metal fusible slag Proposed modes of casting and oh-forming mixture leads to

lgikdeni. provide full kris-that after its crystallization plums

The talization of the metal layer (smelting) to the subsequent smelting ensures the discharge of the subsequent smelting. Before the slag film is melted on the surface, a satisfactory separation of the first layer is made, and its emergence of the metal layers is obtained when the surface of the newly bound layer is sampled.

coats of concubines and metal crushing etc. Thus, crystallization

up to the technological fraction with the usual all layers of metal flows without

overfilling, without using wood-acidification of their surface and welding equipment or other areas, which ultimately i

mechanical strokes. From - .. increases the yield of a valid lack of additional drawall operations. blues when selling 113 acquisitions

dramatically reduces the amount of education; 15 The economic effect will be

The case of off-specs. 100 heavy sleeves.

Claims (2)

1. METHOD FOR FILLING FERRO ALLOYS, including pouring liquid melt into a separation device, separating metal from slag, casting metal into molds and cooling with layer-by-layer crystallization of ingots, characterized in that, in order to reduce mold consumption and increase yield, casting is carried out at metal temperature 50-150С higher than the liquidus line temperature at a speed of 0.3-1.8 t / min. and the cooling of each metal layer to complete crystallization is carried out at a rate of 5-20 ° C / min. 2. The method according to claim 1, with the fact that after pouring “the first layer, the surface of the liquid metal is covered with a low-melting slag-forming mixture. U84105