SU1242530A1 - Method of producing steel - Google Patents

Description

The invention relates to ferrous metallurgy, more specifically, to methods for producing steel with processing liquid metal in a ladle with neutral gas / for example. argon.

The purpose of the invention is to reduce the loss of deoxidizing and alloying and improve the quality of steel.

The smelted metal is released into the ladle, and the lance is introduced into the ladle, and a purge of neutral HbLM gas is started into the ladle. In the course of production and deoxidizing and alloying are introduced into the metal. The consumption of neutral gas in the course of the metal release is continuously reduced and by the end of the purge it is reduced by 1.5-3.2 times the initial consumption. A purge is completed when the bucket is filled with metal at

80-90% of its working volume. The initial 20 guises to reduce the intensity of input

purge neutral gas flow

100-160 m / h.

The moment of the end of the metal N-blow with a PE gas, as well as a continuous destabilizer, and the intensity of its introduction into the metal reduces the circulating speed of the 1CP1 metal in the ladle to the beginning of the slag from the furnace. As a result of this, the interaction of the metal with the slag on the border of their contact decreases and, as a result, the fusion of the alloying elements decreases. In this case, the slag particles are less absorbed from the metal interface - so into the bulk of the metal. As a result, the content of pemetallic blasting in steel is reduced and its quality is improved.

The moment when the metal is purged with a neutral gas, corresponding to filling the bucket with metal at 80-90% of its volume, is optimal both from the point of view of the degree of refining the liquid metal with neutral gas, and in terms of the rate at which the metal in the ladle circulates oven in the ladle. At the same time, if the purging of the metal with a neutral gas is stopped until the bucket is filled to 80% of its volume, effective cleaning of the metal from non-metallic inclusions and gases will not be achieved. If the purge is stopped after filling the bucket with more than 90% of its volume, then by the beginning of the slag discharging into the bucket, there will be an intensive gas cycle of the metal in the bucket, which will lead to HOBbmjeHHOMy carbon alloy

elements contained in steel and non-metallic elements in the metal.

During time 1; e} to the end of the blowdown and the start of the ass to the ladle (2-4 minutes, a reduction in the intensity of metal circulation in the ladle is achieved.

The magnitude of the decrease in the consumption of neutral gas in the course of the release of the metal by the end of the purge depends on the volume of metal in the ladle. With a relatively small bucket volume, for example, 100 tons, it is necessary to continuously reduce the consumption of neutral gas by the end of the backpressure by 1.5 times compared with the initial one. When a large amount of metal in the ladle, for example 300 tons, reducing the consumption of neutral. gas should be more - 3.2 times less than at the beginning of the animation. At the same time, if

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the neutral gas to metal will be below the proposed limit, then by the end of the purge and the standing slag in the ladle, there will be a high rate of metal circulation in the ladle, which will entail the loss of alloying elements and a higher content of non-metallic inclusions in the steel. However, if the continuous reduction in the consumption of neutral gas is more than 3.2 times, then the degree of refining of steel will not be needed,

The magnitude of the consumption of neutral gas at the beginning of the purge is also caused by the mass of metal treated in the ladle. The consumption of neutral gas at the beginning of the ND in the amount of 160 is reasonable in the case of metal processing in buckets with a capacity of 300-350 tons, and 100 - in buckets with a capacity of 50-100 tons. EcjHi consumption of neutral gas is lower than proposed, then a high degree of steel refining will be achieved. At a flow rate above 160 m / h, a 1I1 tepsir disruption of the metal from the ladle is observed, which is unacceptable under safety conditions; moreover, by the beginning of the slag discharging into the ladle, there is a high rate of metal circulation in the bucket. When the flow rate of neutral gas is below 100, it will not be reached. required degree of metal refining,

Example 1. Steel 17 HG is melted in a 300-ton open-hearth furnace, B furnace load charge materials, heat them up, then pour 3

cast liquid iron. The metal is melted and the required temperature and carbon content is molten therein. With a carbon content of 0.12% and a temperature of 1605 C, the metal in the steel-pouring ladle begins to be released from the furnace with a capacity of 300 tons. When the bucket volume is 0.05 of its height with metal, I start blowing with argon flow of 160 m / h with a tuyere inserted into the ladle . Duration of release of melting 12 min. When blowing argon consumption is continuously reduced from 160 m / h to 50. Thus, in the course of production of melting and purging, argon consumption is reduced by 3.2 times compared to its consumption at the beginning of purging. About

the bucket is filled with metal at 90% of its volume. 2.5 minutes after the end of the blow, the slag begins to descend from the furnace into the ladle. In the course of metal production, ferromanganese is added to the ladle in the amount of 15 kg / t and ferrosilicon to 1 kg / t. Then the metal is poured into molds. Compared with the known method of steel production, when metal blowing in the ladle is carried out until the moment when the donkey appears and with a constant flow of argon during the production of smelting, the amount of reassigned and melted low alloyed steel in non-responsible steel grade St.O. decreases from 11.2 to 0.4, as the number of cases in which the chemical composition of the steel deviates from a given steel grade is sharply reduced.

At the same time, the number of slabs subjected to 1xC cleaning from the surface due to the presence of non-metallic inclusions on it, when steel is smelted using the proposed method, decreases 3.5 times as compared with the basic technology. Hire would be rolled on a hot rolling mill on a sheet with a thickness of 9 mm. Leaf culling is reduced from 8.3 to 2.9%. Thus, steel production according to the proposed method allows to improve the quality of the metal at all redistribution and the through exit of the suitable by 6.51%. The specific consumption of ferromanganese was reduced by 0.5 kg / t, and silico-manganese - by 0.6 kg / t.

Example 2. Steel 09 G 2 C melted in a two-bath steel-making furnace. Before the metal is released from the furnace, the carbon content is 0.10%, the temperature of the metal is ISIO C.

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Metal is released from the furnace in a 300-tonne bucket. When filling the bucket with a volume of 0.1, the metal is purged with argon at a flow rate of 100 m / h. Purging is carried out with a continuous decrease in argon consumption and by the end of the purge, which is completed when the ladle is filled with 0.85 of its volume, the argon consumption is 65.

In the course of production in this way, the consumption of argon is reduced by 1.5 times compared to the initial one. 2 minutes after the end of the purge, the slag begins to descend into the ladle. In the course of production of the metal, ferromanganese 18 kg / t and ferrosilicon (65%) 6 kg / t are placed in the ladle. Metal is poured into molds. The number of transfers to steel grade O is reduced by 4 times. Ingots are rolled on sl. Cleaning slabs from the surface due to the presence of non-metallic inclusions is reduced by 2.5 times compared with the basic version of the technology of smelting 5 steel. Spread onto a 20 mm thick sheet. The rejection of metal is reduced from 7.9 to 2.8%. The through yield of the metal increases on average by 6.48%. The metal is more pure in its metallic inclusions m: the number of large (more than 40 µm) inclusions -. reduced by an average of 40%

EXAMPLE 3 Grade 70 steel is smelted in a 300-ton open-hearth furnace. Before discharging 0.71% of carbon from the metal in the furnace, the temperature is 1590 ° C. After filling the 0.15 ladle volume, the metal is purged with argon at a flow rate of 130. By the purge rate, the argon consumption is continuously reduced by the end of the purge when the ladle filled with 80% metal, argon consumption is 65 m / t. During the purge of the flow rate of argon is reduced compared to the initial 2 times. 3 minutes after the end of the purge B, the ladle begins to descend from the slag. During purge in the course of release, ferromanganese and ferrosilicone are placed in the ladle. The metal is poured into varietal ingots, which are rolled into blooms, and then onto a workpiece for wire rope. The through yield of a fit increases by 5.67%. The study of metal contamination with non-metallic inclusions shows that, compared with the base technology, the maximum sulphide score is no more than

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1.5, while the base technical effect of the introduction

Third-generation sulphides occur in terms of economy

go score. Point oxides are not exceeded by ferroalloys by 0.3-0.6 kg / t, but they are 1 point according to the basic technology, while in increasing the yield of

2.5 points. The specific consumption of ferromar-6 - 7% and sheet production

Ghana was reduced by 0.3 kg / t, and ferro-steel of the highest category of quality by 0.5 kg / t, twa by 4 - 5%.

Claims (2)

1. METHOD OF PRODUCING STEEL, including the smelting of metal. In the steelmaking unit, its release into the ladle, its introduction into the metal during the production of melting deoxidizers and alloying, blowing the melt in the ladle with neutral gas, characterized in that, in order to reduce the burning of deoxidizing and alloying and improving the quality of steel, metal inert gas purge is continued until the ladle filling 80-90% of the working volume, wherein the neutral gas flow along the continuous metal tapping reduces and the moment of closure _with produv- ki is reduced in its 1.5-3.2 times on SS compared to the initial. 2. The method according to 1, characterized in that the initial flow rate of neutral gas is 100 160 m ³ / h. '“Ns