SU1747242A1 - Lining of 300-400 ton steel teeming ladles - Google Patents

Abstract

The essence of the invention: the lining includes reinforcing and working stuffed layers, the thickness of the working lining layer varies according to 5 Kp + B, where 6 is the thickness of the working layer; K - coefficient of proportionality, equal to 4-18 mm / m; h is the distance from the top edge of the bucket; B - thickness of the reinforcing layer. The stuffed reinforcing layer is made of sand, and the stuffed worker is made of quartz-clay or alumina masses. 1 hp ff, 6 tab. 1 il.

Description

The invention relates to ferrous metallurgy, namely, steel casting. For steel casting, special steel casting ladles having a refractory lining are used. The capacity of standard ladles for steel casting, as a rule, corresponds to the capacity of the steelmaking unit, from which steel is produced into the ladle, and in modern converter shops is in the range of 300-400 tons. The refractory lining can be made of refractory bricks or printed (or bulk) monolithic mass

The manufacture of lining buckets with a capacity of 300-400 tons for steel casting from piece brick products is a laborious and complex process, requires highly skilled manual labor and slows the widespread introduction of mechanization and automation of lining works. More simple and promising property. MOF lining of buckets, the main advantages of which include the possibility of mechanizing the manufacture of lining and the reduction or complete elimination of the expenditure of piece geese bricks replaced by unshaped refractory masses, the widespread use of relatively inexpensive and non-specified materials. A comparative assessment of the quality of steel cast from buckets with monolithic padded and ordinary brick lining showed that switching to a monolithic padded lining does not affect the quality of cast steel. From an economic point of view, printed and self-leveling monolithic linings of steel casting ladles are equivalent.

The lining of steel-teeming ladles is becoming more and more widespread. As a rule, a refractory monolithic lining consists of two layers of refractory materials: the reinforcing layer (adjacent to the metal body of the ladle) and the working layer (applied to the reinforcing layer and he

VI

N) N Yu

in direct contact with the melt in the ladle when it is used). Characteristics of ramming masses for monolithic lining of ladles used in ferrous metallurgy most often are given in Table. one.

The reinforcement layer of the analogs with a printed working layer is made of brick, which increases the laboriousness of the work and does not allow to completely abandon the practically impossible mechanization and automation of the masonry processes in the lining of the ladle walls. The thickness of the working layer, as well as their total (total) thickness in the buckets with monolithic stuffed lining, is not regulated and is taken arbitrarily in each particular case, based on the design capacity of the steel tile bucket and the need to guarantee exclusion of emergency cases during operation.

The prototype of the invention adopted a padded monolithic lining, the working layer of the walls of which is made of quartz mass 1 (see Table 1), and the reinforcing layer is brick,

At the walls of the bucket, the working stuffed layer of the lining of the prototype has a stepped thickening in the bottom part. In the upper part of the height of the walls of the bucket, the layer of printed lining has the same thickness, and the increased thickness of the bottom layer of the printed lining is also the same.

The disadvantages of all monolithic refractory linings of 300-400 t buckets for casting steel are relatively low resistance compared to brick lining; a large thickness of the working layer and, consequently, a large thickness of the entire lining layer (including the working and reinforcing layers), taken to ensure the elimination of possible accidents during operation without taking into account packing processes during packing, sintering reaction and phase transformations during drying and subsequent operation , which leads to an increase in the cost of mass for the manufacture of lining and reduces the useful volume of the bucket; increased losses of cast steel in the form of scrap, especially when casting the first melting ladle and using a new lining; The use of bricks for the armor layer significantly increases the laboriousness and cost of lining.

The purpose of the invention is to increase the durability of a printed lining; a reduction in the required mass consumption for packing the working lining layer and an increase in the effective bucket volume; reduction of losses of cast steel in the form of scrap; elimination of the use of bricks for the arammatical layer of the ladle walls; decrease

labor intensity of lining manufacturing and its cost; reducing the cost of casting steel and therefore reducing the cost of cast steel.

This goal is achieved by making the reinforcement and working lining of the walls of the steel-teeming ladle with a capacity of 300-400 tons packed with a constant uniform thickness over the height of the wall of the reinforcing layer and varying thickness

working layer according to

(5 Kh + B,

where d is the thickness of the working layer, mm;

K - coefficient of proportionality,

equal to 4-18 mm / m;

h is the distance from the upper edge of the bucket, m;

B - thickness of the reinforcing layer, mm.

The stuffed reinforcing layer is made of sand, and the stuffed working layer is made of quartzite or alumina masses. The working layer of printed lining of high-alumina mass containing (AlaOa +

TU) within 65-75% and having a refractoriness of 1800 ° C, significantly increases the lining durability.

The drawing shows a new design-1 qi lining in accordance with the invention,

The reinforcing printed layer 1 over the entire height of the lining has the same thickness B, mm, and the thickness of the printed working layer 2 varies according to the above dependence 5 Kh + B.

In the event that liquid slag is poured into the ladle in the upper working part of the lining of the walls of the casting ladle, there is a brick slag in contact with the molten slag. The height of the slag in Ca 3 in a steel-teeming ladle with a capacity of 300-400 tons is in the range of 0.3-0.5 m. In case a significant amount of slag does not flow into the bucket, the slag

to c is absent (hi 0).

According to the invention, the stuffed lining of a ladle with a capacity of 300-400 tons for steel casting can be performed according to the applied technology using

typical mechanisms serving for these purposes (for example, the Orbit system and other similar ones).

The final and intermediate values of the thickness of the working layer of the stuffed lining 2 are easily determined by the linear law of its variation in height.

The use of the invention leads to a sharp increase in the durability of the lining (1.5-3.4 times); allows you to achieve a stepwise significant increase in the uniformity of wear of the working lining layer (the limits of the ratio of maximum wear to minimum wear of the working layer of lining are reduced by 2.3-4.1 times at the end of its operation); metal losses with scrap are reduced abruptly (2.5-5.8 times).

The thickness of the reinforcing layer is in the range of 90-100 mm. based on the conditions of sufficient moisture removal without destruction during drying, reliable thermal insulation of the slag-metal melt in the ladle during casting and full use of the working volume of the ladle. When the thickness of the reinforcing layer is more than 100 mm, during heating and drying of the steel-teeming ladle with a capacity of 300-400 tons, the stuffed lining swells up and is partially destroyed due to the deceleration of water vapor. In addition, when the thickness of the reinforcing lining layer is more than 100 mm, the useful working volume of the ladle is significantly reduced. When the thickness of the reinforcing layer is less than 90 mm, the thermal insulation of the molten metal in the ladle is significantly deteriorated, which leads to an increase in metal loss with scrap. Reducing the thickness of the reinforcing layer also reduces the reliability of the printed lining.

The physical essence of the coefficient of proportionality K in the ratio q Kh + B consists in the dependence of the spatial influence of the simultaneous hydrostatic pressure of the metal melt column and its temperatures on the processes of drying, mechanical compaction and sintering of the working lining layer during bucket operation. The thickness of the lining layer, compacted and heated to the temperature of precipitation and evaporation of moisture, increases in direct proportion to the pressure of the metal melt in the experimentally found optimal limits of 4-18 mm / m. At K values of less than 4 or greater than 18 mm / m, the compaction, drying and sintering processes of the stuffed working lining layer occur unevenly, which can lead to increased local heaving and accelerated local destruction of this lining during operation. With increased moisture mass filling value

the coefficient K is chosen within the specified limits closer to the smaller value K. When using a relatively dry tamped mass, the value of the coefficient K is chosen within the specified limits closer to the larger value. The process of compacting and sintering the ramming mass of the working lining layer as a result of the hydrostatic pressure of the slag-metal melt column spreads to a lesser thickness with increasing humidity in the applied mass. In addition, an increase in the thickness of the layer prevents the removal of water vapor, which leads to mechanical

5 the destruction of the monolithic ramming layer when it is heated. The moisture content of the masses used for packing the lining is regulated on the basis of industrial experiments and subsequent widespread

0 use of printed linings in industry. The humidity of the applied masses fluctuated within 7–9% (Table 1). The invention, in addition to the prototype, was tested under production conditions. The mode of drying and heating of the new lining of the buckets in all tests was the same for the prototype and the present invention.

Padded lining buckets are first heated and dried for use for the first time so that the ramming layer is loosened and does not swell. The indicator of the end of heating and drying is the temperature of the metal body of the bucket, which should rise

5 to + 70 ° С. The duration of the drying of the bucket with a padding thickness of 180 mm is 10-12 hours according to a schedule, providing that in the range of 20-150 ° C the temperature rise of the surface of the working layer of the laminate lining is 22-28 ° C / h and at 150 ° C above - 60-70 ° C / h. When the moisture content of the molding material is less than 7%, the drying time of the printed lining is reduced to 8 hours. Test results

5 characterizing the durability of the lining of the casting ladles with a capacity of 300-400 tons are given in Table. 2

Tests have shown that, in accordance with the invention, the working layer is printed

0 lining, made of high-alumina mass, containing + TU within 65-75% with a fire resistance of 1800 ° C, significantly increases the durability of the lining.

5 The data characterizing the uniformity of wear of the stuffed lining of the invention and the lining of the prototype steel tie buckets are given in Table. 3

Data characterizing the effect of the value of the coefficient K ratios Kh

J B but the uniformity of wear of the lining and loss of metal with scrap left in the ladles after the end of the steel casting. are given in table. four.

The long, characterizing the increase in the volume of steel-casting ladles when using the lining-invention, are given in Table 5.

The results of the experiments, which characterize the wear of the working layer of the stuffed lining and the technological effectiveness of its removal from the ladle during repair, are given in Table. 6

The data given in Table 2-5 proves the positive effect of reinforcement and working layers stuffed linings and according to the thickness of the stuffed working layer of the vertical walls of the bucket with a capacity of 300-400 tons to 6 Kh + v, where d is the working layer thickness mm; K is an empirical coefficient equal to 4-18 mm / m; B - constant, numerically equal to the thickness of the reinforcing printed layer; reinforcing printed layer has the same thickness everywhere.

Given in Table. 6 data along with the data table. 1-5 prove the optimal use of high-alumina material in the working layer of stuffed lining with 300-400 ton capacity buckets.

8 as a result of the use of the invention, a substantial increase in the durability of a monolithic stuffed lining of buckets with a capacity of 300-400 tons is achieved; more even wear of the lining and, therefore, exclusion of possible accidents associated with the breakthroughs of liquid steel; increased bucket payload; improving the thermal performance of the lining and therefore reducing the loss of metal with scrap; reducing the cost of casting steel and therefore reducing the cost of steel.

Example 1

1. Baseline data.

11. Masses used for stuffed linings.

1.11. The reinforcement layer is sand with a moisture content of 7.5%.

1.1.2. The working layer is quartzite mass with a moisture content of 7.5%.

., 2. The height from the bottom of the bucket to the top edge of ri2 is 4.6 m.

1.3.Slag height in ca hi 0.4 m.

1.4. The height of the working layer (h2 - hi) is 42 m.

2 Design and manufacture of printed lining.

2.1, Based on the low humidity of the masses, choose the thickness of the reinforcing lining reinforcement layer of 100 mm. The specified thickness of the reinforcement

layer (2.1) is maintained over the entire height of the bucket lining.

2.2 Determine the thickness of the laminated working lining layer at the point of contact with the lining of the bottom of the bucket (2.4) using the formula dg-Kh2 + B, where K is chosen to be 14 mm / m due to low mass humidity

& 14x4.6 + -165 mm.

2.3. Determine the thickness of the ramming working layer (2.2) in the upper part in contact with the slag catfish (2 3)

5i 14 x 0.4 + 100 105 6 106 mm.

2.4. The change in thickness of the ramming working layer increases in height towards the bottom of the bucket along a linear

and can be controlled by a ruler rod or a mold model (the bucket effective volume is an inverted truncated cone).

2.5. The prepared stuffed lining is dried using gas burners in accordance with the above regime.

Example 2. 1. The source data

1.1, Masses used for printed lining.

1.1.1. Armature layer - sand with a humidity of 9%.

1.1.2. Working layer - quartzite mass with a moisture content of 9%

1.2.Height from the bottom of the bucket to the upper edge of ha 4.6 m.

1.3.Slag height by ca hi 0.3 m.

1.4. The height of the working layer (h2 gi) 4.2 m.

2 Design and manufacture of printed lining.

2.1. The output from the increased moisture content of the masses selects the thickness of the ramming reinforcing layer 90 mm. The specified thickness of the reinforcing layer (2.1) is maintained along the entire length of the ladle lining.

2.2. Determine the thickness of the ramming working layer (2.2) of the lining at the point of contact.

it is with bucket bottom lining (2.4.) according to the formula 5 Kh2 + 8, where K is chosen equal to 4 mm / m in connection with increased moisture mass

dj 4 x 4.6 + 90 108 mm.

2.3. Determine the thickness of the ramming working layer (2.2) in the upper part of the contacting with the slag coal (2.3), according to the formula

d% 4x0,3 + 90 91 mm.

2.4. The change in thickness of the ramming layer along the height increases in the direction of the bottom of the bucket according to a linear law q Kh + B and can be controlled using a rod or a forming model (the effective volume of the bucket is an inverted truncated cone).

2.5. The prepared stuffed lining is dried using gas burners in accordance with the given regime.

Froze

1. Source data.

1.1. Masses used for filling the lining.

1.1.1. Armature layer - sand with a humidity of 8%.

1.1.2. The working high-alumina layer has a mass with a content (AfaOa + TiO2) in the range of 65-75% and a humidity of 7%.

1.2. Height from the bottom of the bucket to the upper edge of P2 4.4 m

1.3. Slag height of ca hi 0. The slag does not drain the slag, and the mirror of the liquid steel in the ladle is covered with a thermally insulating neutral layer of powdered solid materials.

1.4. The height of the stuffed working layer (h2 -hi) 4.4-0 0.4m.

2. Design and manufacture of printed lining.

2.1.Select the thickness of the reinforcing layer (2.1) of the lining equal to 95 mm over the entire height of the lining of the ladle.

2.2. Determine the thickness of the working layer (2.2) of the lining at its contact with the lining of the bottom bucket (2.4) according to the formula d% - Kh + B, where K is chosen equal to 18 mm / m

52 18x4.4 + 95 174mm.

2.3. Determine the thickness of the ramming working layer (2.2) of the lining in the upper part, which is at the level of the upper edge of the ladle, according to the formula

(5, 18x0 + 95 95 mm.

2.4. The change in thickness of the ramming layer increases in height towards the bottom of the bucket according to a linear law and can be controlled by means of a rod-line or a forming model (the effective volume of the bucket is an inverted truncated cone).

2.5. Made padded lining is dried using gas burners in accordance with the above regime.

The use of the invention in production does not require any additional costs, work and equipment, and can be recommended for use in all ferrous metallurgy enterprises that have steel-casting ladles with a capacity of 300-400 tons, when casting steel in steel-casting spans of steelmaking. workshops.

Claims (2)

1. Lining of buckets with a capacity of 300-400 tons for steel casting, including a reinforcing layer and a working ramming layer, made with a variable height, which is different. in order to increase the useful volume and reduce steel losses in the form of scrap, the reinforcing layer is made stuffed, and the thickness b of the working layer varies according to d Kh - V. mm where K is a proportionality coefficient equal to 4-18 mm / m; h is the distance from the upper edge of the bucket, m; B - thickness of the reinforcing layer. mm 2. Lining according to claim 1, about tl and h and y and a - so that the printed reinforcing layer is made of sand, and the printed working layer is made of quartzite or alumina the masses Table Properties of masses recommended for monolithic bucket lining Note. content of 3-5% slag of ferrochromic production and liquid glass; Content not more than 1% (Na20 + K20): 3 Content 0.8-0.9% CaO, 1.56 MgO (fraction less than 0.5 mm is 69-88%). table 2 Continuation of table 1 Table 3 Table 4 The average wear of the lining for one melt-bucket, mm / melt Quartzite High Alumina containing (+ TiO2) less 65% Highly lino-zemist containing (+ TYO2) in the range of 65-75% High Alumina, containing (+ TYO2) more than 75% Table 5 Table 6 The manufacturability of removing the footer during repair Easy to remove 20 Easy to remove ten Easy to remove ten Removal is difficult, requires special tools.