SU1585339A1 - Method of comprehensive alloying of electroslag metal - Google Patents

Abstract

The invention relates to electroslag (ES) technology and can be used in the preparation of high quality alloy steels and alloys, as well as in EC welding and surfacing, in the manufacture of bimetallic ingots. The aim of the invention is to improve the quality of the metal and the efficiency of the process. An overheated powder mixture is supplied to the surface of the slag bath, consisting of carbon and oxides of alloying elements (OLE), taken in a stoichiometric ratio. The maximum degree of doping (5 ... 6%), from the point of view of permissible carburization, is determined by the relative carbon content in the mixture, which should not exceed 3% of the mass of the ES of the metal. The minimum effective carbon content in the mixture is 1%. As an OLE, enriched oxide ores can be taken. The stoichiometric ratio of the mixture provides the most complete course of the OLE reduction reaction and the maximum transition coefficient of the element from slag to metal, reaching 40 ... 60%. Pre-grinding and grinding the mixture significantly increases the reactivity of its components. 3 tab.

Description

The invention relates to electropower technology and can be used in the production of high-quality alloy steels and alloys, as well as in electric welding and surfacing, in the manufacture of bimetallic ingots.

The purpose of the invention is to improve the quality of the metal and the efficiency of the process.

When complex doping of electroslag metal by reducing the alloying elements with carbon from oxides according to the invention, carbon

the genus and oxides are fed to the surface of the slag bath in the form of a rubbed mixture in proportion to the stoichiometric coefficients and atomic weights of the reactants, taking into account the transfer coefficients of the alloying element in an amount determined by the carbon content in the mixture - 3% by weight of the electroslag metal,

The interaction of oxides and carbon is mainly due to the reaction:

cl

00 SP

U

co; o

23

I x

OY + YC 2Х ;,

(I)

where X and Y are the stoichiometric coefficients in the oxide formula,

 The ratio of oxide and carbon is expressed

Jjl i

M where m

6Y

(2)

3 /; fOY

M

3i

m mol. weight of the 1st alloying element; proportional weights of i-ro alloying element and carbon required for its reduction, respectively.

When carrying out complex doping, the carbon fraction required for the reduction of individual elements is summarized.

The stoichiometric proportions of the mixture provide the most complete reaction (1) and the maximum transition coefficient of the element from slag to metal. Enriched oxide ores can be used as alloying components.

Use as a reducing agent for carbon is determined by its very high activity during electroslag process. It is capable of restoring most of the used alloying elements from oxides, it is highly technological. Pre-grinding and grinding the mixture significantly increases the reactivity of the components.

Since the mixture is supplied to the surface of the slag bath, where mainly the interaction of the e components occurs, and the carburizing of the slag metal is relatively small. The efficiency of doping with this method is determined by the relative content of carbon in the alloying mixture, which is 1-3% by weight of the remelted metal.

The use of ground powder alloying mixture is dictated by the need to ensure maximum activity of the components at a relatively low density. Sintering, briquetting, pressing the mixture leads to the increase of its density over the slag. This mixture sinks in the slag bath and the carbon mixture is

It rarely comes in contact with a metal bath and is intensively transformed into an ESh metal.

P ROME Complex doping with electroslag remelting of low carbon steel (steel 20) with chromium, vanadium, molybdenum, and silicon was carried out on an A-550 unit using alternating current under the flux of ANF-1. The melted electrode had a diameter of 30 mm, and the mold was 80 mm. The proportions of the components of the doping mixture were determined by the formula

5 QEi95 §. 29 L 29l 12.

Mr

YM

 M,

20

25

thirty

35

40

45

50

55

MSig2.

M.

one

(2)

Given the need for the ratio of alloying elements in the electroslag metal, determine the composition of the mixture portion, g: MoO 2. 12.5; 100; VaOs 25; SiO 22; C 23./

Since practically pure reagents were used to prepare the mixture, their amount was taken in accordance with. calculated values.

Grinding was carried out in a porcelain mortar to obtain a homogeneous powder. The dispersion of particles was 20-100 microns. The addition of the doping mixture was carried out continuously and evenly throughout the entire melting time (in the example 7 minutes). The uneven content of alloying elements in ingot height does not exceed 10%. The degree of doping of the electroslag metal changed depending on the rate at which the mixture was supplied to the surface of the slag bath.

The results of spectral analysis of the ingots are presented in Table. 1 (remelting under flux ANF-1) and table. 2 (remelting under flux ANF-6).

As can be seen from a comparison of the data table. 1 and 2, there are some quantitative discrepancies in the coefficients of assimilation of alloying elements: when remelting under different fluxes, however, the limits characterizing the main distinctive feature are mastered. The fluxes of ANF-1 and ANF-6 are the most common and low active. The implementation of the method with the use of oxidizing fluxes is impractical, since the reduction of their components depending on the required doping system may be undesirable, it is also possible to reduce the coefficients. Overloading of elements with high affinity for oxygen.

 The boundaries of effective application of the method are determined by the maximum permissible degree of carburization (taken 0.02%) of the electroslag metal, which depends on the intensity of carbon loss from the surface of the pshak bath, the recovery scheme of doping oxides, the stoichiometry of the reactions, their mutual influence, the dissolution of doping oxides in the feed rate of the mixture into the slag bath. As established experimentally, there is a certain optimal ratio of components that accounts for the reasons for the occurrence of all these processes under actual conditions of electroslag remelting, which is convenient to associate with the stoichiometry of reduction reactions (Table 3). The use of fluxes containing carbons is possible only for cast irons and high-carbon t melts, then JcaK this method is intended for the treatment of steels with strictly regulated carbon content.

The results are shown in Table. 1 and 2, show also the insignificance of the influence of the process temperature (when melting under the flux of ANF-1, the temperature was 1600 ° C, ANF-6 - on the effective range of carbon.

From the above data, it follows that the most effective doping is 10.7% Cr with permissible carburization) of electroslag metal corresponds to the stoichiometric ratio for reaction (1). Deviation from this ratio by 10% reduces the effectiveness of the method.

The specific combination of components according to this table. 1 and 3 testifies to the effectiveness of the application of the method in various doping systems. The coefficients of assimilation of elements in each case

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can be determined experimentally.

As can be seen from a comparison of the data, the coefficients of transition of elements from slag to metal when feeding a portion of the mixture (23 g of carbon) to 2300 - 750 g of electroslag metal (corresponding to 1-3% of carbon relative to 10 mass of electroslag metal) reach 40-60%. %, which is significantly higher than with other methods of doping with the reduction of oxides. The upper limit of doping, at 5th this, reaches almost 6% (in total for all doping).

When feeding a portion of the alloying mixture to 2500 g of electroslag metal (corresponding to 0.9% C, which is 0 less than 1%), the transition coefficients of the elements fall to 0.11 - 0.17%, which does not exceed those when using alloying fluxes (known). The total reduction of 5 elements does not exceed 0.5%, which is lower than the minimum degree of doping, which has a positive effect on most alloying elements, and can be associated with their oxidation when passing through the slag due to active components and dissolved oxygen.

The introduction of a doping mixture with a carbon content of more than 3% in relation to the remelted metal (when a portion of the mixture is fed to 700 g of the electroslag metal) leads to an unacceptable carburization.

formup of the invention

The method of complex doping of electroslag metal, including the supply to the surface of the slag

Baths of metal oxides and a reducing agent, characterized in that, in order to improve the quality of the metal and the process efficiency, carbon, metal oxides and carbon are used as a reducing agent in the form of a mixture of ground-powders, taken in a stoichiometric ratio, while the amount of carbon in the mixture is 1-3%

from the mass of electroslag metal.

Table 1

The original content of the elements and consumable electrode, wt.X

The calculated content of elements in the ESh metal, wt (at I00% assimilation) when feeding a portion of the mixture to:

2500 g ESH metal 2300 g ESH metal 1500 g ESH metal 750 g ESH metal 700 g ESH metal

The actual content of elements in the electroslag metal, wt.% When applying a portion of the mixture to:

2500 g ESH metal 2300 g ESH metal 1500 g ESH metal 750 g ESH metal 700 g ESH metal

The coefficients of the transition elements from slag in eletroslag metal when feeding a portion of the mixture to:

The original content of the elements in the consumable. Electrode, wt.%

0.21

one

Mp

N1

0.25

0.21 0.52 0.12

Table 2

0.25

0.21 0.52 0.12

The calculated content of elements in the electroslag metal, wt.% (At 100% absorption) when serving a portion of the mixture (see the composition in the description) for

2500 g ESH metal 2300 g ESH metal 1500 g ESH metal 750 g ESH metal 700 g ESH metal

The actual content of elements in the electroslag metal, wt.% When feeding a portion of the mixture to;

2500 g ESH metal 2300 g ESH metal 1500 g ESH metal 750 g ESH metal 700 g ESH metal

The coefficients of the transition elements from slag to metal when feeding a portion of the mixture to:

The estimated cops content in the electrical metal, us: (during assimilation) when the flow is carried down:

2500 g ESh metal 2300 g ESh metal 1500 g ESH metal

0.05

0.12

0.47

0.94

1.11

0,200,500,12

0,220,500,11

0,190,530,11

0,220,490,11

0,300,480,12

Spreadsheets

4.8 5.1 7.9

0.21 0.21 0.21

0.21 0.2 0.21

eleven

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The actual containing non-elements of an eectroish metal, us, when feeding portional mixture to t

2500 g ESH metal 2300 g ESH metal I SCO g E01 metal 750 g ESH metal 700 g ESH metal

. The transition rate of chryl from moisture to metal when feeding a portion of the mixture to;

2500 g ESH metal 2300 g ESH metal 500 g ESH metal 750 g ESH metal 700 g ESH metal

12

Continuation of table 3

0.15 0.32 0.4 0.60 0.67

Claims (1)

Claim The method of complex alloying of electroslag metal, including the supply of metal oxides and a reducing agent to the surface of the slag bath, characterized in that, in order to improve the quality of the metal and the economy of the process, carbon is used as a reducing agent, metal oxides and carbon are fed in the form of a mixture of ground powders, taken in a stoichiometric ratio, while the amount of carbon in the mixture is 1-3%, by weight of electroslag metal. '' 7 1585339 Indicators Table 1 The initial content of the elements in the consumable electrode, wt.% 0.21 The calculated content of elements in the ESH metal, May L (at 100% assimilation) when a portion of the mixture is supplied to: 2500 g ESH metal 2.9 2300 g ESH metal 3.1 1500 g ESH metal 4.8 750 g ESH metal 9.3 700 g ASH metal 9.9 0.25 - 0.21 0.52 0.12 0.37 0.65 0.45 0.21 0.52 0.12 0.40 0.70 0.60 0.21 0.52 0.12 0.63 0.93 0.93 0.21 0.52 0.12 1.31 1,60 1.80 0.21 0.52 0.12 1.42 1.71 2.00 0.2 0.52 0.12 The actual content of elements in electroslag metal wt.% When serving a portion of the mixture to: 2500 g ESH metal 0.56 0.04 0.31 0.05 0.20 Oi-51 0.12 2300 g ESH metal 1.01 0.11 0.39 0.14 0.22 0.53 0.12 1500 g ASH metal 1.94 0.23 0.68 0.56 0.21 0.49 0.10 750 g ASH metal .3.9 0.48 1, 02 0.91 0.23 0.47 0.11 700 g ESH metal 5,0 0.66 1.26 1.28 0.33 0.47 0.11 The coefficients of the transition of elements from slag to electroslag metal when feeding a portion of the mixture to: 2500 g ESH metal 0; 1 5 0.12 0.17 0.11 - - - 2300 g ESH metal 0.29 0.30 0.33 0.25 - - - 1500 g ASH metal 0.38 0.37 0.63 0.60 - - - 750 g ASH metal 0.40 0.38 0.56 0.52 - - 700 g ESH metal 0.42 0.42 0.61 0.48 - - - Tablida 2 The initial content of the elements in the consumable electrode, wt.% 0.21 0.25 0.21 0.52 0.12 9 1585339 ίο 'Continuation of table 2 1 2 : .z 4 5 * 1’1 * The estimated content of elements in electroslag metal, wt.% (At 100% assimilation) when serving a portion of the mixture (composition see description) on: 2500 g ESH metal 2 ,9 0.37 0.65 0.45 0 »21 0.52 0.12 2300 g ESH metal 3 ,1 0.40 0.70 0.60 0 , 21 0.52 0.12 1500 g ASH metal 4 .8 0.63 0.93 0.93 0 , 21 0.52 0.12 750 g ASH metal 9 , 3 1.31 1,60 1.80 0 , 21 0.52 0.12 700 g ESH metal 9 ,9 1.42 1.71 2.00 0 , 21 0.52 0.12 Actual Content elements in the electrical waste wrought metal, wt. ^ when serving a portion of the mixture on the: 2500 g ESH metal 0 51 0.05 0.30 0.05 0 ,20 0.50 0,1 2 2300 g ESH metal 0 93 0.12 0.40 0.12 0 , 22 0.50 0.11 1500 g ASH metal 1 82 0.24 0.68 0.47 0 19 0.53 0.11 750 g ASH metal 3 ,9 0.50 1, 01 0.94 0.22 0.49 0.11 700 g ESH metal 4 6 0.57 1.18 1,11 0.30 0.48 0.12 Conversion factors elements from slag in me- serving portion serving mixtures on: 2500 g ESH metal 0 AND 0.13 0.15 0.11 - - - 2300 g ESH metal 0 25. 0.29 0.27 0.20 - - - 1500 g ASH metal 0 35 0.38 0.59 0.51 - - - 750 g ASH metal 9 0 41 0.38 0.61 0.52 - - - 700 g ESH metal about, 45 0.41 0.63 0.55 - - - T a b faces 3 The composition of the alloying mixture cg from - 213.4 g Cg, ° ₃ 194 g Cg, 0 ₃ 174 6 g Cr, O _A 213.4 g Cr 194 g CtjO, Ι7ά, 6 g ♦ ♦ + + + + 23 g FROM 23 g from 23 g C 23 g C 23 g from 23 g C Estimated content of elements in electroslag metal, May L: (at 100X assimilation) when feeding a portion of the mixture to: 2500 g ESH metal 5.5 5.5 4.8 0.21 0.21 - 2300 g ESH metal • ⁵ · ⁹ 5.9 5.1 0.21 0.21 - 1500 g ASH metal 9.0 9.0 7.9 0.21 0.21 - eleven Continuation of table.Z Composition SG FROM 213.4 g Cr, 0 ₃ 194 g CrjOj 174.6 g Cr ₄ 0z - 213.4 g CpjOj 194 g Cr, 0 ₃ 174.6 g C _g 0 ♦ ♦ + + + ♦ 23 g C 23 g C 23 g C 23 g C 23 g C 23 g C 750 g EV metal 17 in 17.8 15.8 0.21 0.21 - 700 g of metal waste 19.1 19.1 17.0 0.21 0.2! - Actual content of elements & electroslag metal, May L when serving a portion of the mixture at t 2500 g ESH metal 0.69 1, 06 0.90 0.18 0.1 9 0.21 2300 g ESH metal 0.89 1, 85 1.78 0.18 0.20 0.19 1500 g ASH metal 3,1 3.4 3.3 0.20 0.22 0.21 750 g ASH metal 7.9 10.7 9.6 0.21 0.23 0.26 700 g ESH metal 9.1 12.1 11.5 0.31 0.36 0.41 The conversion coefficient of chromium ne yalaha to metal when a portion of the mixture is fed to: 2500 g ESH metal 0.09 0.16 0.15 - - - 2300 g ESH metal 0,1 2 0.29 0.32 - - - 1500 g ASH metal 0.33 0.39 0.41 - - - 750 g ASH metal 0.43 0.61 . 0.60 - - - 700 g ESH metal 0.47 0.63 0.67 - - '-