SU1219656A1 - Method of producing structural low-alloyed steel - Google Patents

Description

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The invention relates to metallurgy, in particular to the production of steel in open-hearth furnaces, as well as in converters.

The purpose of the invention is stabilization. assimilation of titanium.

Studies have shown that from methods aimed at stabilizing the assimilation of titanium by metal, the most technologically advanced and effective is to deoxidize steel with sumarganese mixed with a complex alloy containing titanium, aluminum and silicon. This can be explained by the fact that aluminum contained in the alloy, as a stronger deoxidizing agent, prevents titanium from oxidizing. In addition, it has been found that deeper metal deoxidation is achieved if the complex alloy contains, in addition to aluminum, silicon,. The formation of the CACO 2SiOg compound causes a decrease in the deoxidizing ability of both aluminum and silicon. In this case, the higher the content of silicon in the alloy, the higher the stability and degree of absorption of titanium. However, when the content of silicon is more than 20%, the density of the alloy and the melting point are sharply reduced, as a result of which the stability and the degree of assimilation of titanium decrease. Therefore, silicon is additionally introduced into the metal in the form of silicomanganese mixed with a complex alloy (SiAlTi).

The high degree of assimilation of titanium and the stability of its content in steel are obtained when the alloy is introduced in the amount of 1.5-2.3 kg / t of steel in mixture with silicomanganese at the indicated ratio. If the alloy is introduced in an amount of less than 1.5 g / g / t of steel, the deviation of the actual titanium content from the calculated one increases due to insufficient input of aluminum and alloy into the steel to prevent the oxidation of titanium. When the alloy is introduced in the amount of more than 2.3 kg / t of steel, the stability of titanium absorption decreases, and the steel pollution increases with non-metallic inclusions.

The alloy addition in the amount of 1.5-2.3 kg / t of steel allows to obtain steel with a minimum deviation of the actual titanium content from the calculated one. In addition, non-metals9656

These inclusions are more favorably positioned over the grain, which makes it possible to obtain steel with high resistance to brittle fracture.

1J However, a stable titanium content can be obtained only if the alloy is introduced in a mixture with silico-manganese, and the ratio of silico-manganese and SiAlTi alloy

0 must be (2-5): 1, At a ratio of less than 2: 1 or more than 5: 1, increased titanium waste is observed. When the bulk of the silico manganese is introduced into the furnace, then in the first

In case of the case, in the ladle metal in the melting zone of the alloy there is not enough silicon, and in the second case, the metal has a higher oxidation before being released into the ladle.

As a preliminary deoxidation, a small amount of manganese is consumed in the furnace.

The smallest deviations of the actual titanium content from the calculated

5 (the stability of the assimilation of titanium) and its carbon monoxide are established when the ratio of the titanium content to the sum of aluminum and silicon is 0.45-0.6. When the ratio of titanium to the sum is aluminum and silicon

0 less than 0.45 decrease in the stability of the assimilation of titanium due to the increased oxidation of the alloy In the ladle due to oxygen in the air due to its low density (less than 3.5 kg / cm) and low melting point (melting point below 1100 C), If the ratio is greater than 0.6, the decrease in the stability of the assimilation of titanium is explained by the low content of aluminum and silicon in the alloy, protecting titanium from oxidation.

To determine the stability and the degree of absorption of titanium with an application. The method of production of low-alloy steel construction was carried out by experimental melting, the results of which are given in the table,

The titanium content is determined chemically by the standard 0 procedure.

Steel is smelted in a 300-ton open-hearth furnace. The refining of the metal in the furnace is carried out by introducing lime and pointing slag with a basicity of 5 not less than 2.5. Fifteen minutes before the release, pre-deoxidation of the steel in the furnace with silico-manganese was performed. When releasing from the oven to the ladle

water final metal deoxidation with silico-manganese mixed with silicon-aluminum titanium alloy

(5; AetO.

The composition of the alloy (SjABTi),%: titanium .20-2.5; aluminum 20-25; silicon 15-20; iron - the rest.

From the data in the table it follows that when the alloy consumption is 1.5-2.3 kg / t of steel and the mass ratio of silico-manganese and alloy is 2-5, and also if the ratio of the titanium content in the alloy to the sum of silicon and aluminum is 0.45- 0.6 The proposed method for the production of titanium-containing steel provides for the production of steel with a stable content of titanium with the maximum degree of assimilation. Absolute deviation of titanium content

3.0, 0.58

1,90,58

2,60,44

2.00.46

2.50.46

4,00,60

5.00.45

5,10,48

3,00,58

2,80,61

1.2 8.3

196564

0.008-0.016%, relative 25-34.8%, degree of titanium digestion 65-75%.

According to industrial data, the proposed

5, in comparison with the known method, it is possible to increase the degree of stabilization of titanium in steel — the deviation of the actual titanium content from the calculated one is two times lower, while

The 10 degree of absorption of titanium is almost twice as high.

Thus, the proposed method for the production of low-alloy structural steel will allow for the introduction of technology, allowing -. titanium-containing steel with a stable titanium content of titanium (0.01-0.03%), significantly reduce

 waste of titanium and 1.5 times reduce the consumption of ferroalloy.

23,217,1

23,217,1

25,222,5

25,220,9

25,220,9 20,116,8

24,820,1

25,220,9

23,116,5

18,117,8

Editor B, Petrash

Compiled by K.Sorokin Tehred L.Oleynik

Order 1235/36

 Circulation 552

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Branch PGS Patent, Uzhgorod, st. Project, 4

Table continuation

Proofreader O. Lugova

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Claims (2)

1. METHOD FOR PRODUCING CONSTRUCTION LOW-ALLOYED STEEL, including refining metal in a steel-smelting unit, preliminary deoxidation with silicomanganese, production and final alloying of metal in a ladle with silicomanganese, aluminum and titanium, characterized in that silicomanganese is introduced into the mixture with the aim of stabilizing titanium absorption silicoaluminium-titanium alloy with a ratio of (2-5): 1, and the alloy is introduced in an amount of 1.5-2.3 kg / t of steel. _from 2. The method according to π. 1, due to the fact that the silicoaluminium-titanium alloy is introduced with a ratio of titanium to the sum of aluminum and silicon of 0.45-0.60. SU „., 1219656 ί 121