阅读说明：本技术 一种转炉出钢口、转炉及转炉砌筑、出钢方法 (Converter tapping hole, converter and converter building and tapping method ) 是由 汪成义 杨利彬 赵进宣 王彦生 王思福 王杰 吴巍 于 2020-06-18 设计创作，主要内容包括：本发明公开了一种转炉出钢口、转炉及转炉砌筑、出钢方法,属于钢铁冶金技术领域,解决了现有技术中转炉出钢效率低,转炉出钢下渣量大,冶金效果差,转炉的出钢口使用寿命低的问题。本发明的转炉出钢口包括出钢口环形砖,出钢口环形砖内部形成钢水通道,其中,钢水通道的数量为两个。转炉包括转炉出钢口和转炉炉体,转炉出钢口设置在转炉炉体的一侧,钢水通道的轴线与转炉的轴线的夹角为80～84°。本发明的转炉出钢效率高,出钢下渣量小,出钢口的寿命提高。(The invention discloses a converter steel tapping hole, a converter and a converter building and tapping method, belongs to the technical field of ferrous metallurgy, and solves the problems that in the prior art, the converter steel tapping efficiency is low, the converter steel tapping slag quantity is large, the metallurgical effect is poor, and the service life of the converter steel tapping hole is short. The converter tap hole comprises a tap hole annular brick, and two molten steel channels are formed inside the tap hole annular brick. The converter comprises a converter steel tapping hole and a converter body, the converter steel tapping hole is arranged on one side of the converter body, and an included angle between the axis of the molten steel channel and the axis of the converter is 80-84 degrees. The converter has high tapping efficiency, small tapping slag amount and prolonged service life of the tapping hole.)

1. The converter tap hole is characterized by comprising a tap hole annular brick (7), wherein a molten steel channel (5) is formed inside the tap hole annular brick (7), and the number of the molten steel channels (5) is two.

2. The tapping hole of the converter according to claim 1, characterised in that said two molten steel channels (5) are parallel and side by side in the same axial section of the converter; or the two molten steel channels (5) are distributed in parallel in the same radial section of the converter.

3. The converter tap hole according to claim 1, characterised in that said two molten steel channels (5) are of the same size.

4. The converter tap hole according to claim 1, characterized in that the diameter d1 of the inlet end of said molten steel channel (5) is greater than the diameter d2 of the outlet end, said molten steel channel having a trapezoidal axial section.

5. The converter tap hole according to claim 1, characterized in that said tap hole annular brick (7) has a chemical composition of, by mass, 82.5-85.1% of MgO, 12.2-15.5% of graphite, 1.3-1.6% of carbon black, and 0.7-1.1% of Ce-Fe alloy.

6. A converter, characterized in that it comprises a converter body and a converter tap hole according to claims 1 to 5, said converter tap hole being arranged at one side of the converter body, the angle between the axis of the molten steel channel (5) and the axis of the converter being 80-84 °.

7. The converter according to claim 6, characterized in that the converter tap hole is of a split structure, the converter tap hole comprises a tap hole ring brick (7), a tap hole jacket brick (8), a tap hole outer pocket brick (9), a tap hole inner pocket brick (4) and a tap hole shell (10), the tap hole ring brick (7) is arranged in the tap hole jacket brick (8), the tap hole outer pocket brick (9) and the tap hole shell (10) are sequentially arranged outside the tap hole jacket brick (8) at the side of the converter tap hole outer pocket, and the tap hole inner pocket brick (4) is arranged in the wall of the converter body.

8. The method of constructing a converter according to claim 7, wherein the refractory bricks (1) are constructed from the bottom of the converter when constructing the converter to the vicinity of the tap hole in the shaft portion, the inner pocket brick (4) of the tap hole is first installed, the outer pocket brick (9) of the tap hole is then installed, the outer pocket brick (8) of the tap hole is pushed in after the inner pocket brick (4) and the outer pocket brick (9) of the tap hole are constructed in a ring shape, the two ring bricks (7) of the tap hole are inserted into the outer pocket brick (8) of the tap hole, the gap portions of the refractory bricks are filled with refractory mortar, and the outer pocket brick (10) of the tap hole is finally fixed.

9. A method for tapping from a converter, characterized in that the converter according to claim 6 or 7 is used, comprising the following steps:

the method comprises the following steps: when smelting is finished, the ladle car (12) carrying empty ladles is driven to the bottom of the converter, the converter is slowly tilted to the position where the axis of the molten steel channel (5) is vertical to the horizontal plane, two molten steel channels (5) simultaneously tap steel and reach the maximum tapping speed, and the ladle car (12) is slowly moved forwards and backwards to promote the uniform mixing of the components of the molten steel (2);

step two: and after tapping, closing the two molten steel channels (5) in sequence, and recovering the zero position of the converter.

10. The converter tapping method according to claim 9, further comprising:

step three: after tapping, tracking and repairing the tapping hole, firstly carrying out nitrogen slag splashing operation, after the slag splashing operation is finished, adding 500-1000 kg of lime into the converter to improve the alkalinity of slag, then using a high-alkalinity slag-hanging protection technology, shaking the converter back and forth to enable a slag layer to be formed by adhesion near a molten steel channel, and pouring the residual slag out of the converter.

Technical Field

The invention relates to the technical field of ferrous metallurgy, in particular to a converter steel tapping hole, a converter and a converter building and steel tapping method.

Background

The tap hole has special significance for the converter lining, and is the only passage for molten steel to enter a ladle from a converter. Because the molten steel amount of the steel-tapping hole is large, the steel-tapping hole needs to bear the scouring and oxidation erosion of high-temperature molten steel all the time, the working condition is very bad, the service life of the steel-tapping hole is very short under the general condition, the repair or replacement period is short, and the production stability and the molten steel quality are directly influenced. The structure of the steel tapping hole has important influence on the steel tapping operation of the converter, the steel tapping time of the molten steel channel with the smaller diameter is longer, so that the smelting period is influenced, the production efficiency is reduced, the erosion of the annular brick of the steel tapping hole is accelerated, the steel tapping time of the molten steel channel with the overlarge diameter is shorter, the slag stopping operation is also adversely affected, the formed molten steel flow vortex is easy to increase the slag discharge amount, and meanwhile, the molten steel channel is eroded by high-temperature molten steel for a long time, the steel tapping hole is seriously deformed, and severe production accidents such as steel drilling, steel leakage and the like are easily caused.

According to the different requirements of the size and steel grade of the converter, the common slag blocking modes of the converter comprise a slag blocking ball, a slag blocking dart, pneumatic slag blocking and a sliding plate slag blocking method. The slag blocking ball or slag blocking dart method is simple to operate and low in cost, can effectively control slag discharge vortex, and has unstable hit rate. In the use process of pneumatic slag stopping, molten steel and steel slag are easy to splash out, the maintenance difficulty is high, the eddy slag rolling is obvious, and the fluctuation of the slag stopping effect is large. The sliding plate has high slag blocking speed and high hit rate, but the later slag blocking effect is poor due to uncontrollable slag discharge rotational flow, and the increase of the diameter of the steel tapping hole can lead to the increase of the contact area of the sliding plate and the molten steel, thereby causing great influence on the service life of the sliding plate. Therefore, the design of the steel tapping hole needs to comprehensively consider the influence of various slag stopping modes on the steel tapping effect.

The applicant shows through intensive research that the slag amount from the converter tapping to the ladle at the early stage is approximately 30%, the slag amount brought from the surface of the molten steel by the vortex effect is approximately 30%, the slag amount at the later stage is approximately 40%, therefore, how to reduce the slag discharge amount in the whole tapping process by reasonably improving the tapping hole is particularly important, most of the current research works are realized by improving the refractory material of the tapping hole, or optimizing the inlet and outlet diameters of the tap hole and lowering the tap temperature to improve the life of the tap hole, such as a horse steel by enlarging the diameter of the tap hole to 210/240mm, the steel ladle slag-off amount is controlled and the steel tapping speed is improved by the way of sliding plate slag-off and slag-off detection, a certain effect is achieved, but the requirements on the manufacturing process and the quality of refractory materials of the sliding plate are higher, the use cost is increased, and the sliding plate is not suitable for common small and medium converters.

Disclosure of Invention

In view of the above analysis, the present invention aims to provide a converter and a method for tapping from a converter, which can solve at least one of the following problems: (1) the existing converter has low tapping efficiency; (2) the slag discharge amount of converter tapping is large, and the metallurgical effect is poor; (3) the service life of the steel tapping hole of the converter is short.

The purpose of the invention is mainly realized by the following technical scheme:

in one aspect, the present invention provides a converter tap hole, which includes a tap hole ring brick having two molten steel passages formed therein.

Furthermore, the two molten steel channels are parallelly distributed in the same axial section of the converter in parallel; or the two molten steel channels are parallelly distributed in the same radial section of the converter in parallel.

Further, the two molten steel passages have the same size.

Further, the diameter d1 of the inlet end of the molten steel channel is larger than the diameter d2 of the outlet end, and the axial section of the molten steel channel is trapezoidal.

Furthermore, the chemical compositions of the steel tapping hole annular brick comprise, by mass, MgO82.5% -85.1%, graphite 12.2% -15.5%, carbon black 1.3% -1.6%, and Ce-Fe alloy 0.7-1.1%.

The invention also provides a converter, which comprises the converter steel tapping hole and a converter body, wherein the converter steel tapping hole is arranged at one side of the converter body, and the included angle between the axis of the molten steel channel and the axis of the converter is 80-84 degrees.

Further, the converter tap hole adopts split type structure, and the converter tap hole includes tap hole annular brick, tap hole outer sleeve brick, tap hole outer pocket brick, tap hole interior pocket brick and tap hole shell, and tap hole annular brick sets up in tap hole outer sleeve brick, and at converter tap hole outer port side, tap hole outer sleeve brick has set gradually tap hole outer pocket brick and tap hole shell outward, and the setting of tap hole interior pocket brick is in the furnace body wall.

The invention also provides a construction method of the converter, when the converter is constructed, refractory bricks are constructed from the bottom of the converter, when the converter is constructed to the position near the steel tapping hole of the converter body, firstly, a brick cup in the steel tapping hole is placed, then, a brick cup outside the steel tapping hole is placed, after the brick cup in the steel tapping hole and the brick cup outside the steel tapping hole are constructed in an annular manner, the brick cup outside the steel tapping hole is pushed in, then, two annular bricks of the steel tapping hole are embedded into the brick cup outside the steel tapping hole, gaps of the refractory bricks are filled with refractory clay, and finally, a shell of the steel tapping hole is fixed.

The invention also provides a converter tapping method, which comprises the following steps:

the method comprises the following steps: when smelting is finished, the ladle car carrying the empty ladle is driven to the bottom of the converter, the converter is slowly tilted to the position where the axis of the molten steel channel is vertical to the horizontal plane, two molten steel channels simultaneously tap steel and reach the maximum tapping speed, and the ladle car is slowly moved forwards and backwards to promote the uniform mixing of molten steel components;

step two: and after tapping, closing the two molten steel channels in sequence, and recovering the zero position of the converter.

Further, the method also comprises the following steps:

step three: after tapping, tracking and repairing the tapping hole, firstly carrying out nitrogen slag splashing operation, after the slag splashing operation is finished, adding 500-1000 kg of lime into the converter to improve the alkalinity of slag, then using a high-alkalinity slag-hanging protection technology, shaking the converter back and forth to enable a slag layer to be formed by adhesion near a molten steel channel, and pouring the residual slag out of the converter.

Compared with the prior art, the invention has the following beneficial effects:

(a) the converter tap hole provided by the invention adopts a split structure, so that the construction of the tap hole is convenient, and independent component design and processing can be carried out on the ring-shaped brick of the tap hole with serious erosion.

(b) The two molten steel channels are arranged at the steel tapping hole of the converter, the size and the position of the molten steel channels are accurately controlled, the structure of each steel tapping hole of the converter is convenient to manufacture and install, and the molten steel can be ensured to smoothly enter a steel ladle through the molten steel channels; in addition, the invention shortens the smelting period and reduces the erosion speed of the annular brick of the steel tapping hole, thereby prolonging the service life of the steel tapping hole and reducing the incidence rate of steel tapping accidents;

(c) in addition, the converter tap hole can be suitable for a converter with the capacity of 50-300 t, slag blocking modes such as slag blocking balls, pneumatics and sliding plates can be adopted when the converter is adopted, and compared with a sliding plate slag blocking mode, the converter smelting cost can be greatly reduced when the common slag blocking ball slag blocking mode is adopted.

(d) According to the converter, under the same condition, the diameter of the molten steel channel is smaller than that of a single-hole steel outlet, so that the molten steel flow vortex is reduced during steel tapping, the difficulty of slag blocking operation is reduced, the slag entrapment phenomenon formed by the large molten steel flow vortex is avoided, the integral slag discharge amount of the converter is reduced by more than 10%, and the molten steel quality is improved;

(e) the tapping speed of the converter tapping method provided by the invention is 1.5-2 times of the original tapping speed, after the tapping efficiency is improved, nitrogen absorption and secondary oxidation in the air in the molten steel tapping process are reduced, the pollution of molten steel is reduced, the corrosion of the annular brick at the tapping hole is slowed down, the deformation is not obvious, and the service life of the tapping hole is obviously prolonged.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and drawings.

Drawings

The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the invention, wherein like reference numerals are used to designate like parts throughout.

FIG. 1 is a schematic three-dimensional cross-sectional view of a rotary kiln according to the present invention; wherein (a) the two molten steel channels are parallelly distributed in parallel in the same axial section of the converter (namely, in a vertical form); (b) two molten steel channels are parallelly distributed in the same radial section of the converter in parallel (namely in a horizontal mode);

FIG. 2 is a schematic vertical section through a vertical form tap-hole converter according to the invention;

FIG. 3 is a schematic front view of the vertical form tap-hole of the present invention;

FIG. 4 is a schematic view of the tapping process of the vertical form tap-hole converter of the present invention;

FIG. 5 is a schematic vertical section of a horizontal tap-hole converter according to the invention;

FIG. 6 is a schematic front view of the horizontal tap-hole of the present invention;

FIG. 7 is a schematic view of the tapping process of the horizontal tap-hole converter of the present invention.

Reference numerals:

1-refractory bricks; 2-molten steel; 3-furnace shell; 4-brick setting in the tap hole; 5-molten steel channel; 6-heat insulation plate; 7-ring-shaped brick of the steel tapping hole; 8-sleeving bricks outside the steel tapping hole; 9-brick cup outside the steel tapping hole; 10-tapping hole casing; 11-a ladle; 12-ladle car.

Detailed Description

The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form a part hereof, and which together with the embodiments of the invention serve to explain the principles of the invention.

The invention provides a converter tap hole, as shown in figures 1 to 3, the converter tap hole adopts a split structure, the converter tap hole comprises a tap hole annular brick 7, a tap hole outer sleeve brick 8, a tap hole outer brick cup 9, a tap hole inner brick cup 4 and a tap hole shell 10, the thickness of the tap hole inner brick cup 4 is matched with the wall thickness of a furnace body along the tap direction of the tap hole, the inner brick cup 4 in the tap hole is annularly arranged to form an inner port of the tap hole, one end surface of an annular inner port formed by the tap hole inner brick cup 4 forms the inner surface of the furnace body, the other end surface of the annular inner port formed by the tap hole inner brick cup 4 is annularly provided with the tap hole outer brick cup 9, and the annular outer surface of the tap hole inner brick cup 4 is connected with the surrounding furnace body wall; inside the ring of brick cup 4 in the steel tapping hole and the inside ring of brick cup 9 outside the steel tapping hole are provided with steel tapping hole outer cover brick 8 that runs through terminal surface in brick cup 4 in the steel tapping hole and the outer terminal surface of brick cup 9 outside the steel tapping hole, steel tapping hole outer cover brick 8 forms two cavity inner chambers, the inner wall of two cavity inner chambers is equipped with steel tapping hole annular brick 7, inside molten steel passageway 5 that forms of steel tapping hole annular brick 7, through adopting above-mentioned split type structure, can not only make things convenient for building by laying bricks or stones of steel tapping hole, and can carry out independent component design and processing to steel tapping hole annular brick 7 that the erosion is more serious.

Specifically, as shown in fig. 1(a), two molten steel passages 5 are arranged in parallel in the same axial section of the converter (i.e., in a vertical manner), that is, when the converter is suspended in a vertical direction, one molten steel passage is directly above the other molten steel passage; by adopting the mode, the converter can be conveniently placed along the same line in the later tapping stage, and simultaneously is in the same moving direction with the steel ladle, thereby being beneficial to matching with the steel ladle and uniformly mixing the molten steel. If one molten steel pathway is located laterally above the other molten steel pathway, it is not easy to grasp the angle for controlling the tapping speed before the tapping is finished.

In one possible design, as shown in fig. 1(b), two molten steel passages 5 are arranged in parallel side by side (i.e., in a horizontal form) in the same radial section of the converter.

Specifically, considering that the tapping speeds are different if the sizes of the two molten steel passages 5 are different, the tapping speeds are not easily controlled during use, and the erosion of the ring-shaped brick 7 of the tapping hole is different, which is not beneficial to the uniform maintenance and replacement of the ring-shaped brick, the sizes of the two molten steel passages 5 are controlled to be the same.

Specifically, one end of the molten steel channel 5 extending into the furnace body is called an inlet end, and one end of the molten steel channel 5 extending out of the furnace body is called an outlet end, so that in order to weaken the interference between molten steel and the ring-shaped brick 7 of the tap hole, ensure the smooth steel flow and increase the tapping speed, the diameter d1 of the inlet end of the molten steel channel 5 is larger than the diameter d2 of the outlet end. The axial section of the molten steel channel is trapezoidal.

Specifically, the diameter d1 of the inlet end of the molten steel channel 5 is too large, the slag discharge amount is increased, the tapping time and the smelting rhythm are prolonged due to too small diameter, therefore, the d1 is controlled to be 120-150 mm, the erosion of the annular brick 7 of the tapping hole is accelerated due to too large diameter d2 of the outlet end, the tapping time and the smelting rhythm are prolonged due to too small diameter, therefore, the d2 is controlled to be 90-120 mm, and the length of the molten steel channel 5 is 1500-1800 mm.

The invention also provides a converter, which comprises the converter steel tapping hole and a converter body, wherein the converter steel tapping hole is arranged on one side of the converter body. Wherein, the converter body comprises a furnace shell 3 and refractory bricks 1 arranged on the inner side of the furnace shell 3.

In order to increase the heat insulation, a heat insulation plate 6 is arranged between the furnace shell 3 and the refractory bricks 1 at the furnace body part.

Specifically, the included angle between the axis of the molten steel channel 5 and the axis of the converter is 80-84 degrees, because the two molten steel channels 5 can reach the conditions of simultaneous tapping and the same tapping speed when the converter is shaken to tap steel by setting a proper angle, the stroke of the ladle car during tapping is shortened, and when the maximum tapping angle is reached, a furnace mouth has a certain upward inclination angle, so that the operation safety is improved.

Considering that the distance between the central lines of the two molten steel channels 5 is too large, the molten steel is easy to splash out of the steel ladle after passing through the molten steel channels 5, and meanwhile, the molten steel is not beneficial to moving the steel ladle back and forth and mixing the molten steel uniformly; the distance is too small, the heat effect on the central part of the annular brick 7 of the steel tapping hole can be superposed, two steel flows passing through the molten steel channel 5 are easy to interfere with each other, and the action range after entering a steel ladle is limited, so that the distance between the central lines of the two molten steel channels 5 is controlled to be 600-1000 mm.

Compared with the prior art, the converter steel-tapping hole provided by the invention is provided with the two molten steel channels, the size and the position of the molten steel channels are accurately controlled, the split structure is adopted, the arrangement is standard, the size is reasonable, the structure manufacturing and the installation of the converter steel-tapping hole are convenient, and the molten steel can be ensured to smoothly enter a steel ladle through the molten steel channels.

The converter tap hole shortens tapping time and reduces the erosion speed of the annular brick of the tap hole, thereby prolonging the service life of the tap hole and reducing the incidence rate of tapping accidents; under the same condition, the diameter of the molten steel channel is slightly smaller than that of a single-hole steel outlet (the diameter of an inlet and an outlet of the traditional steel outlet molten steel channel is generally between 150 and 240 mm), and because the Reynolds number Re which shows the degree of liquid flow turbulence in the round pipe is in direct proportion to the pipe diameter, when the size of the molten steel channel is reduced, the disturbance vortex of the molten steel flow caused by steel outlet is reduced, the difficulty of slag blocking operation is reduced, the slag entrapment phenomenon formed by the large vortex of the molten steel flow is avoided, the overall slag falling amount of the converter is reduced by more than 10 percent, and the quality of the molten steel is improved; in addition, the converter tap hole can be suitable for a converter with the capacity of 50-300 t, the converter tap hole can be suitable for slag blocking modes such as slag blocking balls, pneumatics and sliding plates, and the slag blocking effect of the slag blocking balls adopted by the molten steel channel with the smaller size is better, so that when the common slag blocking mode of the slag blocking balls is adopted, compared with the slag blocking mode of the sliding plates, the converter smelting cost can be greatly reduced.

After the tapping efficiency of the converter tapping hole is improved, nitrogen absorption and secondary oxidation in the air in the molten steel tapping process are reduced, and the pollution of the molten steel is reduced.

It should be noted that, in order to improve the corrosion resistance of the annular brick 7 of the tap hole, the material of the annular brick 7 of the tap hole needs to be accurately controlled, and the chemical compositions of the annular brick 7 of the tap hole are 82.5-85.1% by mass of MgO, 12.2-15.5% by mass of graphite, 1.3-1.6% by mass of carbon black, and 0.7-1.1% by mass of Ce-Fe alloy. The addition of carbon black can further increase the bulk density of the ring-shaped tap hole brick 7, and the alloy containing rare earth elements has a higher affinity for oxygen than carbon in graphite, and is oxidized preferentially to carbon to protect carbon, thereby further improving the oxidation resistance of the ring-shaped tap hole brick 7.

Specifically, the annular brick 7 of the steel tapping hole is manufactured by processing technologies such as crushing, accurate proportioning, mixing and forming, a mechanical compaction mode is adopted during forming, the mechanical compaction forming can ensure that the volume density of the annular brick 7 of the steel tapping hole is high, and specifically, the volume density of the annular brick 7 of the steel tapping hole is more than 2.9 g.cm^-3The apparent porosity is less than 4.5%, the normal temperature compressive strength is more than 30MPa, and the high temperature rupture strength is more than 10 MPa.

The invention also provides a construction method of the converter, when the converter is constructed, the magnesia refractory bricks 1 are constructed from the furnace bottom in the furnace shell 3, when the construction is carried out to the position near the steel tapping hole of the furnace body, firstly, the inner brick cup 4 of the steel tapping hole is arranged, then, the outer brick cup 9 of the steel tapping hole is arranged, after the inner brick cup 4 of the steel tapping hole and the outer brick cup 9 of the steel tapping hole are constructed in an annular manner, the inner brick cup 8 of the steel tapping hole is pushed in, after the steps are completed, the two annular bricks 7 of the steel tapping hole are embedded into the outer brick cup 8 of the steel tapping hole, the gaps of the refractory bricks are filled with refractory clay, and finally, the outer shell 10 of the steel tapping hole.

It should be noted that, the converter adopts the masonry method, and because the two molten steel channels 5 are both manufactured on the outer sleeve brick 8 of the steel tapping hole, the processing and the installation are convenient, the operation difficulty in the masonry process is reduced, and the masonry and the use safety is improved.

The invention also provides a converter tapping method, which adopts the converter and comprises the following steps:

the method comprises the following steps: when smelting is finished, the ladle car 12 with empty ladles is driven to the bottom of the converter, the ladles are aligned to the two molten steel channels, the converter is slowly tilted to the position where the axis of the molten steel channel is vertical to the horizontal plane, the two molten steel channels simultaneously tap steel and can reach the maximum tapping speed of 100t/min (the existing tapping speed is generally 50-70 t/min), and the ladle car is slowly moved forwards and backwards to promote the uniform mixing of molten steel components;

step two: after tapping, closing the two molten steel channels in sequence, and recovering the zero position of the converter;

step three: after tapping is finished, real-time tracking repair is carried out on the tap hole, nitrogen slag splashing operation is firstly carried out, after the slag splashing operation is finished, 500-1000 kg of lime is added into the converter to improve the alkalinity of slag, then a high-alkalinity slag hanging protection technology is used, the converter is shaken back and forth to enable the parts near the two molten steel channels to be attached to form slag layers, the slag layers are used for protecting refractory materials on the inner wall of the annular brick of the tap hole, the refractory materials on the inner wall of the annular brick of the tap hole are prevented from being corroded, and redundant slag is poured out of the converter.

Specifically, in the first step, when the axis of the molten steel channel is perpendicular to the horizontal plane, the contact time of the molten steel 2 in the air is increased due to the fact that the distance H between the outlet of the steel-tapping hole and the top of the steel ladle 11 is too long, the molten steel 2 is oxidized by the air, the distance H is too short, the molten steel 2 is easy to touch the upper edge of the steel ladle, the fluctuation of the liquid level of the steel ladle and the addition of a deoxidizing agent and the like are not easy to observe, and therefore the distance H between the outlet of the steel-tapping hole and the top of.

Specifically, in the third step, the angle of the converter which is rocked back and forth is too large, so that the slag is easy to overflow from the converter mouth, and if the angle is too small, the aim of slag hanging maintenance of the steel tapping hole cannot be achieved, so that the angle of the rocking converter is controlled to be 75-80 degrees.