SU996070A1 - Steel ingot production method - Google Patents

Description

-one - ---.

The invention relates to ferrous metallurgy, in particular to the production of steel in converters, open-hearth furnaces and two-bath units.

Nowadays, ferracerium, mismetal and complex master alloys 1,2 are used to modify and microlengthen iron-carbon melts with rare-earth metals (REC).

In connection with the high means of rare-earth metals to oxygen and sulfur, when these alloys are introduced into the furnace or ladle, low absorption of rare-earth metals is observed. For increasing the degree of assimilation of P, forced immersion of REM alloys in the ladle 3 is used.

However, this method of modifying and micronizing steel in. existing open-hearth and converter shops are associated with the need for slag cutting, the use of basic lining of buckets and other organizational difficulties, -; ;

Therefore, in order to increase the level of rare-earth metals, microelementation and modification of steel by alloying RZN are carried out on casting G 3, 3. The closest to the invention in its technical essence is the method of modifying and micro-alloying liquid steel steel siphon during casting. In this case, prior to the mischmetal additive, the liquid metal is dissolved and alloyed in neviH with silicomanganese and ferrochrome, the final deoxidation in the ladle is ferrosilicon, then aluminum (Q, Q / t, 5 steel) and ferrotitanium (1.5 kg / t one hundred / w ). Mischmetall REM in the form of 1 barrels weighing 400-500 g introduces uniformly in the center in the process of filling the molds Up to the profitable part 5.

The disadvantage of this method

20 is the uneven distribution of rare earth metals in the bulk of the ingot, caused by its addition to the centrifugal unit without taking into account the variable c. the process of casting the mass flow rate of metal from the ladle and a large fraction of the ligature (00-500 g, i.e. 30- > 0 mm in diameter). This leads to the unevenness of the mechanical and technological properties of metal products, reducing its yield. . The purpose of the invention is to increase the uniform distribution of rare earth metals in the volume of the ingot. This goal is achieved by the fact that according to the method of manufacturing steel ingots, including alloying and deoxidation of steel produced in the aggregate with solid ferroalloys and aluminum when it is released into the ladle and microalloying with rare earth metals ligatures by introducing into the center of the molds during the siphon casting process, rare earth metal ligature pieces fractions of 2–9 mm, when filling the mold with steel, from 0.02 of the height of the working CAVITY continuously to the level of the profit cavity with a speed proportional to m assoy speed of filling the molds with steel, and the total content of aluminum and titanium in the steel before microalloying is maintained in the range of 0.02-0.10%. The lower (0.02) and upper (to the level of the profitable cavity) height of the height of the molds, at which ligatures are introduced, are justified by the considerations of preventing REM losses in the bottom and profitable parts of the ingots (cut off) and ensuring proper averaging Ligatures in the volume of the ingot when pouring metal in full jet. Minimum sizes of ligature pieces (2 mm) are taken from the need to prevent significant and unstable losses of REM as a result of surface oxidation by air oxygen. The maximum sizes of the ligature pieces (9 mm) were adopted in order to ensure complete dissolution of the ligature during the process of filling the molds with metal and uniform distribution of rare-earth metals in the metal volume of the ingots. The continuous introduction of a ligature at a rate proportional to the mass of the speed of filling the molds with steel is due to the need to ensure a uniform content of REM in the ingot volume under varying conditions of metal casting. The lower limit of the total content of aluminum and titanium in steel before microalloying is assumed to be 0 (02, since at lower concentrations of these elements the effect of preliminary melt deoxidation is insufficient, which leads to a sharp decrease in the level and stability of the absorption of rare-earth metals. The upper limit of the total content of aluminum and titanium (0.10) in steel before micro-doping is limited by the amount above which the quality of the ingot surface deteriorates significantly. The invention is based on the fact that the continuous introduction of a rare-earth metal alloy in pieces of size oh 2-9 mm in the process of siphon casting to the center when filling the molds from 0.02 ingot body height to the level of the profitable part with a speed proportional to the mass speed of filling the molds with steel, provides the most uniform distribution of rare earth metals in the ingot volume, and regulated within 0 , 02-0.10, the total content of aluminum n titanium in the melt before micro-alloying helps to minimize the loss of rare-earth metals as a result of oxidation by oxygen dissolved in the metal. Comparative tests of the proposed and known methods of steel smelting for welding wire are carried out. The metal smelted in oxygen converters with a capacity of 50 tons with a temperature at the outlet of 16201 BSA was doped and smelted sequentially in a ladle by silicocalcium. b5% ferrosilicon, aluminum and ferrotitanium. The chemical composition of steel (bucket tests) is as follows: 0.10-0.13 C; 1.61-1.93 ° Mn; 0.711, 2% Si; 0.024-0.025% S; 0.0150, 028% P, - 0.015-0.075% Ti; 0.0050, 025% L1. The casting was siphoned into downward-extending molds with insulating liners on ingots weighing 12.5 tons, located on the same pallet. Microalloying of steel through the center is carried out in two ways. a) The ligature of rare-earth metals SCTSISH-2 (average consumption k, S kg / t steel) in pieces of a fraction of 2-9 mm is introduced continuously when the molds are filled from 0.02 ingot body height to the level of profitable part at a rate proportional to mass velocity filling the molds with steel, while ensuring the total content of aluminum and titanium before micro-doping in the range of 0.02-0.10%. The mass filling rate of the molds is determined by the formula V.A. Yefimov. b), Misch metal in pieces with a mass of O, 0.5 kg in the amount of I, kg / t of steel are uniformly introduced into the centering part of the mold filling to the level of the warping part. . Data on the mass fill rate of the molds and the speed of insertion of the lug into the center during casting is given in Table. 1. Investigate the distribution of rare earth metals in the volume of ingots manufactured according to the proposed and well-known methods. From rolls, ingots (a square of 80-80 mm in size) on the horizons, respectively, 16, 17, 22, 27, 32, 37, "2.47, 52, 57. 62, 67, 72, 77, 82, 87.92 and the ES from the upper end, select macrotemplets. From the three points of each tempglet, corresponding to their edge, middle and center, chips are taken for chemical. The results of the study of the homogeneity of the chemical composition of the steel produced by the proposed and known methods are given in Table. 2. Given in Table. 2 data indicate that steel production by the proposed method provides a more uniform distribution of rare-earth metals in the volume of the ingot than by the known method. This causes an increase in the technological properties of metal products. For example, when using welding wire with REM obtained according to the proposed technology, the stability of the gas-electric welding process is improved and the metal loss due to spraying at -21 is reduced. The economic effect in the national economy in the amount of 2.8-5.6 rubles / ton of wire is provided. Table 1

Proposed

2 10 20

3Q "Yu 50 60 70 80

eSCEMISH-2

3.85 33.75 31.87 29.97

g

27.66 25.38 22.19 19.35

e7

0.60 (jet braking)

0.60 (jet braking)

Claims (1)

Invention Formula The method of manufacturing steel ingots, which includes alloying and deoxidation of steel produced in the aggregate with solid ferroalloys and aluminum when it is released into the ladle and microalloying with pieces of rare earth metal alloy by introducing 996070 8 Continued table. one 7.78 Misch metal Table 2 When casting, it is necessary to increase the uniformity of distribution of rare earth metals by ingot volume, pieces of ligature are introduced in fractions of 2-9 mm in size when filling the molds with steel from 0.02 times the height of the working cavity to profitable cavity at a rate proportional to 9/99607010 National Mass Velocity-tals Reviews, 1978, vol. 23i ng 2, mold casting with steel, moreover. . content of ayomini and titanium. Cossacks I.G1, and others. Before using microalloying, the basement of rare-earth elements was kept in the range of 0.02-0.101 $ carbon steel. Sat MeSources of information, tallurgists and coke chemistry. Kiev, Technical data into account when examining, 1965, p. 160-165. 1. Drawings. A. Steel production and ferroalloys.M., Metallurgists, 1975..5. Zigalo I.N. and others, Makrostruktu2. The author's testimony of the USSR RA steel 15HSND with additives seldomN, cl. C 22 C 35/00, 1976. Earth metals. Bulletin of the Institute 3.Woudby P.E. Rare earth add - Chermetinformatsi, 1968, 1G20, ttons to steel. International He-c-3iJ-39.