RU2373468C2 - Arched steel furnace of small capacity - Google Patents

Abstract

FIELD: metallurgy industry.

SUBSTANCE: invention refers to metallurgy industry, to development of design of arched steel furnace of small capacity. Arched furnace includes casing, lining, electrode arms, electrodes, roof ring, sand lock, chill arch forming working door, shutter with lifting mechanism, gutter with outlet for tapping and slagging and mechanism of furnace inclination. Working door is located above gutter with outlet for tapping and slagging, at that lower parts of working door and outlet for tapping and slagging have one horizontal axis and shutter is lowered to vertical ribs of gutter.

EFFECT: invention allows to enhance resistance of furnace lining and to reduce its maintenance areas.

5 dwg, 1 tbl

Description

This invention relates to metallurgy, and in particular to the design of a small-capacity arc steel furnace (DSP).

In our country, serial three-phase arc furnaces of small capacity are produced and operated - 0.5, 1.5, 3 and 5 tons [1].

The designs of furnaces of different capacities differ little in configuration, and their sizes are directly related to the mass of the smelted metal [1, 2, 3]. A typical design of chipboard is shown in figure 1.

The furnace has the following structural elements: a casing (1) with a drain toe (trough) (2), a working window (figure 2) and a sand lock (3), a vault ring (4), a lining (5), two tilting cylinders of the furnace, the mechanism for lifting and turning the arch or lifting the arch and the roll-out of the bath, electrode holders with secondary conductors, electrode movement mechanisms, electrode seals and a water cooling system.

The working window (figure 2) is intended for the maintenance of chipboard in preparing the unit for melting and throughout the entire process. It consists of a shutter (7), a water-cooled arch (6), a threshold, a comb (crowbar bracket) (8) and a shutter lift mechanism, the main elements of which are a bracket (9) and a pneumatic cylinder (10). In some cases, to ensure rigidity of the design of the working window, a frame is welded into the opening of the furnace casing. The damper should fit snugly against the frame of the working window. The dimensions of the loading window should allow inspection and refueling of the slopes of the entire furnace, introduce ferroalloys and deoxidizers into the working space, remove electrode fragments from the furnace, and intensively download slag. In the lower part of the working window, a cast-iron plate is fixed, which serves as the basis for the threshold of the furnace, consisting of a refractory lining, from which metal scraps and slag are easily removed. Combs are used to facilitate the work of personnel when downloading slag, taking a sample of metal and mixing it [3]. A steel bar is placed on the combs and the combs are moved along it to enter them into the furnace. Particleboard is tilted to download slag in the direction of the working window at an angle of 10 ÷ 15 ° and to drain the metal in the opposite direction at an angle of 40 ÷ 45 ° [2].

In the most difficult conditions, there is a part of the lining, framing the arches of the working window and the outlet. As a rule, the destruction of the lining begins with the loss of individual bricks mainly around the arch of the working window and above the outlet, as well as delamination of the refractory particles from the working surface of the lining and its cracking.

The causes of destruction are:

1) periodic cooling of the inner surface of the lining due to stops for its local repairs;

2) weakening of the overall design of the lining due to the lack of continuity of its inner surface;

3) the lining of the furnace is not monolithic;

4) during the melting process, the furnace is tilted in two opposite directions when the metal is drained and slag is downloaded, and in the first case, the furnace is tilted up to an angle of 45 °, while the refractory masonry around the working window tilts inward, which contributes to the loss of bricks from it;

5) uneven temperature distribution in the lining.

The invention solves the problem of developing a new design of an arc steel furnace of small capacity, the technical result of the invention is to increase the resistance of the refractory lining. This goal is achieved by changing the design of the casing of the furnace, namely the location of the working window from the diametrically opposite side of the casing above the chute (figure 3), while the device of the working window practically does not undergo changes. This is facilitated by the fact that the working window and the outlet at the bottom have one horizontal axis.

The height of the flap will slightly decrease - by the size of the diameter of the outlet, since it lowers onto the vertical edges of the gutter.

It should be noted that in a small-capacity chipboard, the dimensions of the gutter are small, which practically does not complicate its maintenance from the work site.

For the functioning of the proposed design of the casing, it is necessary to redevelop the service area of the furnace (s), shown in Fig.4, 5, as follows:

1) move the main control panel (12) by the furnace (11) to the place (13), i.e. on the side of the furnace where the working window and the gutter are located;

2) install a mobile working platform (5) above the large pit (14), which is moved from the furnace along the axis of the trench before downloading slag and draining the metal;

3) in the case of a common large pit for two furnaces (left-handed and right-handed furnaces) (Fig. 5), the platform (15) can be rolled out onto the track perpendicular to the front of the furnaces, while according to the requirements of industrial safety rules, warning signs are placed on the prohibition during casting passage in this zone.

For free lowering of the bucket during metal production and downloading the entire required amount of slag without replacing the slag for at least one melt, it is necessary to use low slag in the large pit 150–200 mm high and wider.

Changes in the design of the chipboard casing gives the following advantages:

1) increase the lining resistance, i.e. reduced consumption of refractories;

2) reducing downtime for minor repairs to the lining (above the arch);

3) the second control panel of the furnace is not required (16, Figs. 4, 5), used when releasing metal from the furnace, since the steelmaker in this situation should see a trench and a stream of metal;

4) protection against splash of slag of the hydraulic cylinders of the furnace tilt, located under the working window of the prototype casing;

5) when downloading slag through the gutter, it warms up, which to a certain extent reduces the decrease in temperature of liquid steel during its release;

6) reduced service area of the furnace crane.

Brief Description of the Drawings

Figure 1 presents a General diagram of an arc steel furnace (DSP). The main elements of the furnace are the casing (1), the chute (2), the sand lock (4), the arch ring (3), the lining (5), the water-cooled arch (6), the shutter (7), the comb (8).

Figure 2 presents the mechanism for lifting the shutter. The damper (7), which fits snugly to the water-cooled arch (6), is lifted upward using the damper drive bracket (10). The same figure shows the location of the comb (crowbar) (6).

Figure 3 shows a General diagram of an arc steelmaking furnace of a new design. The main elements of the furnace: a casing (1), a chute (2), a vault ring (3), a sand lock (4), a lining (8), a water-cooled arch (5), a shutter (6), a comb (7). The design is distinguished by the location of the water-cooled arch, damper and comb located above the outlet. Damper height reduced by outlet size.

Figure 4 presents the layout of the chipboard. Elements shown on the plan: chipboard (11), chipboard control room before modernization (12), chipboard control panel after modernization (13), large pit (14), mobile platform (15), chipboard control panel (16). The use of a new casing design allows you to remove the second control panel (16), because the drain of the melt from the furnace is visible from the new room where the control panel of the furnace is located. The mobile platform is moved along the axis of the gutter to open a large pit.

Figure 5 presents a plan of the location of two chipboard (with a new casing design). Elements shown on the plan: chipboard (11), chipboard control room before modernization (12), chipboard control panel after modernization (13), large pit (14), mobile platform (15), chipboard control panel (16). After the modernization, pos.12 will be transferred to the position pos.13, as a result, the gutter is visible and both additional control panels (16) will be removed. The movable platform (15) may be located above the large pit during melting and move perpendicular to the axis of the furnaces to release the pit during the discharge of the melt.

Technical and economic indicators of steel smelting 35 and 45 in an acid arc steel-smelting furnace DSP-0.5 (bath capacity 0.7 tons of liquid steel) for three smelting campaigns carried out before and after the furnace modernization are given in the table.

Name of parameters Basic version Proposed option The number of swimming trunks in the campaign 66 67 64 69 72 73 Average number of swimming trunks per campaign 65.7 71.3 Refractory consumption without (roof), kg / t steel 6.49 6.28 6.76 6.23 5.96 5.87 The average consumption of refractories, kg / t of steel 6.51 6.02

The presented data showed that a change in the design of the casing made it possible to reduce the consumption of refractory dinas brick per bath by 7.5% and limit the control of the furnace from one panel.

LITERATURE

1. Bornatsky I.I., Mikhnevich V.F., Yartin S.A. Steel production. M .: Metallurgy, 1991 .-- 400 p.

2. Soifer V.M., Kuznetsov L.N. Arc furnaces in a steel shop. M .: Metallurgy, 1989 .-- 176 p.

3. Kablukovsky A.F., Molchanov A.E., Kablukovskaya M.A. A quick reference to electric steel. M .: Metallurgy, 1994 .-- 352 p.

Claims (1)

A small-capacity arc steel furnace containing a casing, lining, electrode holders, electrodes, a vault ring, a sand gate, a water-cooled arch forming a working window with a shutter having a lifting mechanism, a chute with an outlet for draining metal and releasing slag, and a furnace tilt mechanism, characterized the fact that the working window is made over the chute with an outlet for draining metal and releasing slag with the possibility of lowering the shutter on the vertical edges of the chute, while the lower parts of the working window and the outlet The holes for the discharge of metal and the discharge of slag are located on the same horizontal axis.

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