TW201942362A - Top-blow lance and method for covering top-blow lance - Google Patents

Abstract

To provide a top-blow lance and a method for covering a top-blow lance with which the adhesion of bare metal to the outer surface of a lance main body section can be reduced. A top-blow lance according to the present invention is a water-cooled top-blow lance comprising: a lance main body section; a nozzle section provide on the tip end of the lance main body section; and a cover section that is provided with respect to at least a portion of an outer tube of the lance main body section, and that contains copper and/or nickel and/or cobalt as a constituent element.

Description

Top-blowing spray gun and coating method of top-blowing spray gun

FIELD OF THE INVENTION The present invention relates to a top-blowing lance that supplies gas to the inside of a processing vessel such as a converter and a coating method thereof.

BACKGROUND OF THE INVENTION Most of the processing vessels used for steelmaking use a converter and remove the impurities such as phosphorus and carbon contained in molten pig iron in the converter by supplying oxygen from a spray gun inserted into the converter. For example, the top-blowing lance is used by being inserted into a processing container such as a converter from the upper part, and spraying oxygen from above the molten pig iron to supply oxygen for removing impurities, and functions as a power source for stirring the molten pig iron. Has important functions. Generally, top-blowing lances are mostly made of steel pipes. In addition, since the inside of the converter during the dephosphorization treatment and the decarburization treatment is at a high temperature, a cooling mechanism for preventing damage due to heat is provided in the top-blowing lance.

When the top-blowing lance is used, when the oxygen supply rate from the top-blowing lance is large, or when molten pig iron in a processing vessel such as a converter is stirred at a high speed, the spatter of molten pig iron scattered from the surface of the molten pig iron bath increases, and Adhesion of the raw metal to the inner wall of the processing container occurs. At this time, not only the inner wall of the processing container, but also the outer barrel of the top-blowing lance inserted into the processing container is also attached to the raw metal. In addition, when the interval between the molten pig iron and the spray gun is shortened in order to improve the efficiency of removing impurities, it becomes easier to attach the raw metal to the outer barrel of the spray gun.

If a large amount of raw metal is adhered to the outer barrel of the spray gun and there is a large amount of accumulation, the raw metal that has accumulated on the outer barrel of the spray gun is stuck when the top blowing spray gun is removed from the processing container after the blowing step for removing impurities is completed. The spray gun on the upper part of the processing container passes through the opening, and it becomes impossible to remove the top-blowing spray gun from the processing container. Most of the conventional top-blowing lances use carbon steel, and it is easy to form raw metal adhesion due to spraying. Therefore, the operation of removing the raw metal from the top-blowing lance must be performed frequently, resulting in an increase in the number of working hours. In addition, in the auxiliary hole spray gun, if the auxiliary hole is blocked due to the raw metal, the oxygen injection bias flow from the auxiliary hole will be caused. The possibility of life. In addition, because the raw metal attached to the outer barrel of the spray gun is recovered as waste, the product yield is reduced.

Also, the top-blowing lance may use stainless steel, but the chromium (Cr) contained in the stainless steel reacts with the CO gas generated during the smelting to generate chromium carbide on the surface of the outer barrel of the lance. Because the chromium carbides produced are relatively brittle, there is a possibility of cracks that could cause damage to the top-blowing lance.

To solve this problem, methods have been developed to prevent the adhesion of the raw metal to the spray gun.

As a method for preventing the adhesion of the raw metal to the spray gun, for example, Patent Document 1 below discloses a spray gun. The spray gun uses a copper tube in the lower half of the outer barrel of the spray gun and uses the high thermal conductivity of copper. The raw metal can be easily peeled off without causing the raw metal to be fused to a copper pipe that is cooled by molten steel.

An oxygen spray gun is disclosed in Patent Document 2 below. In an oxygen spray gun with a water-cooled sleeve, a smooth surface finish grinding process is applied to the outer surface of the outer barrel of the spray gun to increase the heat transfer coefficient and increase the heat transfer coefficient. The attached molten steel is rapidly cooled to prevent melting on the surface of the spray gun.

Patent Document 3 below discloses a spray gun for converter blowing, in which a cast iron spray layer is provided on the outer surface of a steel tube and the outer surface of a copper nozzle, and the raw material is blocked by graphite precipitated on the surface of the cast iron. Metal adhesion.

Patent Document 4 below discloses a metal smelting spray gun which is a metal including a metal component composed of a Co-based alloy or a Ni-based alloy and a ceramic component composed of TiN in the metal smelting spray gun. The ceramic film is formed by coating on the metal base material by thermal spraying, so that the molten metal is not adhered, and peeling does not occur in the film base material boundary portion.
Prior art literature patent literature

Patent Literature 1: Japanese Patent Laid-Open No. 1-129920 Patent Literature 2: Japanese Patent Laid-Open No. 3-120544 Patent Literature 3: Japanese Patent Laid-Open No. 4-88109 Patent Literature 4: Japanese Patent Laid-Open No. 8-199221 Bulletin

SUMMARY OF THE INVENTION Problems to be Solved by the Invention However, the spray gun disclosed in Patent Document 1 in which the lower half of the outer cylinder is a copper pipe has a lower stress than a steel pipe because the copper pipe has a lower stress than a steel pipe. The possibility that the half is deformed to obtain a sufficient gun life.

In addition, the spray guns disclosed in Patent Documents 2 and 3 cause surface deterioration due to CO gas generated during the reaction and increase the emissivity. Therefore, the temperature of the surface of the outer barrel of the spray gun is increased, which makes it easier. There is a possibility that the raw metal adheres, and there is a possibility that a sufficient working man-hour reduction effect cannot be obtained.

In addition, the spray gun of Patent Document 4 in which a cermet coating is formed on a metal base material has thermal stress in the tensile direction with respect to the base material on the adhesion surface of the cermet coating, so it may cause cermets The film was peeled. In addition, there is a case where the cermet film is peeled off due to stress concentration on a fine cracked portion of the cermet film. Therefore, there is a possibility that the raw metal adheres and accumulates on the peeling part of the cermet film, and it is impossible to obtain a sufficient spray gun life and a reduction in working hours.

As described above, in the conventional spray gun, the method of suppressing the accumulation of raw metal on the outer surface of the spray gun main body is not sufficient. From the viewpoint of reducing the number of man-hours for maintenance work, extending the life of the spray gun, and reducing the yield, There is room for improvement.

Accordingly, the present invention has been made in view of the above problems, and an object thereof is to provide a top-blowing lance and a coating method of the top-blowing lance that can further suppress the adhesion of raw metal to the outer surface of the main body of the lance.
Means to solve the problem

In order to solve the above-mentioned problems, the inventors of the present invention conducted intensive studies and obtained the following knowledge. By covering at least a part of the outer barrel of the main body of the spray gun with a coating portion containing a predetermined metal as a constituent element, The above-mentioned problem can be solved by conceiving the covering method and providing the covering section.
The gist of this invention completed based on the said knowledge knowledge is as follows.

(1) A top-blowing spray gun is a water-cooled top-blowing spray gun and includes: a spray gun body portion; a nozzle portion provided at a front end of the spray gun body portion; and a covering portion with respect to at least an outer cylinder of the spray gun body portion. It is partially provided, and contains at least any one of copper, nickel, and cobalt as a constituent element.
(2) In the top-blowing lance described in (1), the arithmetic average roughness Ra of the surface of the coating portion specified in JIS B0601: 2013 is 3 μm or less.
(3) In the top-blowing spray gun described in (1) or (2), the coating portion is at least a part of a surface that can be positioned in the processing container in the outer tube.
(4) The top-blowing lance described in any one of (1) to (3), wherein the covering portion is a welding portion provided to cover at least a part of the outer cylinder among portions that can be positioned in the processing container.
(5) The top-blowing lance described in any one of (1) to (4), wherein the covering portion is formed using copper, and the thickness of the covering portion is 300 μm or more.
(6) The top-blowing spray gun according to any one of (1) to (4), wherein the covering portion is formed using nickel, and the thickness of the covering portion is 180 μm or more.
(7) The top-blowing lance described in any one of (1) to (4), wherein the coating portion is formed using cobalt, and the thickness of the coating portion is 110 μm or more.
(8) A coating method for a top-blowing spray gun is a coating method for a water-cooled top-blowing spray gun including a spray gun main body and a nozzle portion provided at a front end of the spray gun main body, and using a coating material to cover the spray gun main body. At least a part of the outer tube, and the coating material includes at least any one of copper, nickel, and cobalt as a constituent element.
(9) The coating method for the top-blowing lance described in (8) is to coat at least a part of the outer cylinder such that the arithmetic average roughness Ra of the coated surface is 3 μm or less as specified in JIS B0601: 2013.
(10) The coating method of the top-blowing spray gun according to (8) or (9), wherein at least a part of the outer cylinder is covered by spraying, surfacing, or plating the coating material.
(11) The coating method of the top-blowing lance described in (10), wherein at least a part of the outer cylinder is covered by spraying the covering material, and the covering part formed by the covering material is machined into: The arithmetic mean roughness Ra of the surface according to JIS B0601: 2013 is 3 μm or less.
(12) The coating method of the top-blowing lance according to any one of (8) to (11), wherein the coating portion formed by the coating material is a surface of the outer cylinder that can be positioned on the surface of the processing container At least a part.
(13) The coating method of the top-blowing spray gun according to any one of (8) to (12), wherein the coating site formed by the aforementioned coating material is a part which can be positioned in the processing container and is present in the aforementioned outer cylinder At least a part of the weld.
(14) The coating method of the top-blowing spray gun according to any one of (8) to (13), which uses a coating material containing copper as a constituent element as the aforementioned coating material, and coats the aforementioned coating material into the final coating material. The thickness is 300 μm or more.
(15) The coating method of the top-blowing spray gun according to any one of (8) to (13), which uses a coating material containing nickel as a constituent element as the aforementioned coating material, and coats the aforementioned coating material into the final coating material. The thickness is 180 μm or more.
(16) The coating method of the top-blowing spray gun according to any one of (8) to (13), which uses a coating material containing cobalt as a constituent element as the aforementioned coating material, and coats the aforementioned coating material into a final The thickness is 110 μm or more.
Invention effect

As described above, according to the present invention, the adhesion of the raw metal to the outer surface of the spray gun body can be further suppressed.

Embodiments for Implementing the Invention Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In this specification and the drawings, constituent elements having substantially the same functional configuration are given the same reference numerals, and redundant descriptions are omitted here.

> Overview of Top Blow Converter Equipment>
In the embodiment of the present invention described below, a description will be given by taking a top-blowing converter as an example of a processing container using a top-blowing lance. First, referring to Fig. 1, a schematic configuration of a top-blown converter facility will be described. FIG. 1 is a schematic explanatory diagram showing the configuration of a top-blown converter equipment using a top-blown lance of this embodiment.

The converter equipment includes: a converter body 10, the shell of which is made of iron sheet, and refractory construction is performed on the inside thereof; and a top-blowing spray gun 11, which is inserted into the converter body 10 from the furnace mouth 12 above the converter body 10 and is set to It can move up and down in the converter. An exhaust hood 20 is connected to the furnace mouth 12 of the converter body 10, and the gas inside the converter body 10 is exhausted through the exhaust hood 20. The exhaust hood 20 is provided with a spray gun passage opening 22 for inserting or removing the top-blowing spray gun 11 inside the converter above the converter body 10.

In the steelmaking step, the converter body 10 is subjected to a process of removing impurities contained in the molten pig iron 5. The converter body 10 contains molten pig iron 5 containing impurities. The molten pig iron 5 in the converter body 10 reacts with oxygen blown from a top blowing lance 11 inserted into the converter body 10 through the furnace mouth 12 and slag raw materials and refining agents charged from the furnace mouth 12. Impurities such as phosphorus and carbon contained in the molten pig iron 5 are removed from the molten pig iron 5. By this reaction, the phosphorus removed from the molten pig iron 5 forms a slag 9. The carbon contained in the molten pig iron 5 becomes CO gas, and the CO gas reacts with oxygen to become CO ₂ gas, and is discharged from the furnace mouth 12 through the exhaust hood 20 to the outside of the furnace. The outer cylinder surface of the top-blowing lance 11 is deteriorated by the CO gas generated from time to time. In addition, the raw metal 7 is easily attached to the inner wall of the converter body 10 or the spray gun body portion of the top-blowing spray gun 11 due to the splash.

Therefore, in the top-blowing spray gun of this embodiment, as described in detail below, a process such as preventing adhesion of the raw metal 7 to the outer cylinder of the spray gun body can be performed. Thereby, adhesion and accumulation of the raw metal 7 to the top-blowing lance can be suppressed, and work load such as trimming of the top-blowing lance can be reduced.

<Detailed Description of Top Blow Gun 100>
The configuration of the top-blowing lance 100 of this embodiment will be described in more detail with reference to FIGS. 2 and 3. FIG. 2 is an explanatory diagram showing a schematic configuration of the top-blowing lance 100 according to this embodiment. FIG. 3 is an explanatory diagram showing the components of the top-blowing lance 100 according to this embodiment.

The top-blowing spray gun 100 of this embodiment is a water-cooled spray gun, and as shown in FIG. 2, it includes a first cylindrical portion 110, a second cylindrical portion 120, a third cylindrical portion 130, and a main hole arranged coaxially. 102. In addition, the top-blowing lance 100 has a coating portion 140 on at least a part of the outer surface of the third cylindrical portion 130. The first cylindrical portion 110, the second cylindrical portion 120, and the third cylindrical portion 130 constituting the spray gun body portion 151 are configured using, for example, carbon steel or stainless steel. The nozzle portion 153 is made of, for example, copper. Hereinafter, as shown in FIG. 3, a portion of the top-blowing spray gun 100 composed of the first cylindrical portion 110, the second cylindrical portion 120, and the third cylindrical portion 130 is referred to as a spray gun body portion 151, and is provided with A portion of the main hole 102 provided at the front end of the spray gun body portion 151 is referred to as a nozzle portion 153. In the first cylindrical portion 110, the second cylindrical portion 120, and the third cylindrical portion 130, the surface on the center axis side is used as the inner surface, and the outer surface is used as the outer surface.

The first cylindrical portion 110 is a hollow member positioned at the innermost portion of the top-blowing lance 100. The first cylindrical portion 110 communicates with the main hole 102 at the front end of the top-blowing lance 100, and the oxygen fed from an oxygen supply source (not shown) is supplied from the main hole 102 to the inside of the converter body 10.

The second cylindrical portion 120 is a hollow member that covers the outer surface of the first cylindrical portion 110. As shown in FIG. 2, a first space V ₁ through which a cooling medium flows is formed by an outer surface of the first cylindrical portion 110 and an inner surface of the second cylindrical portion 120. As the cooling medium, for example, water can be used. The first space V ₁ communicates with a second space V ₂ described later in the nozzle portion 153 at the front end of the top-blowing lance 100.

As shown in FIG. 3, the first cylindrical portion 110 and the second cylindrical portion 120 are inner cylinders 151 a constituting the spray gun body portion 151.

The third cylindrical portion 130 is a hollow member that covers the outer surface of the second cylindrical portion 120 and is positioned at the outermost portion of the top-blowing lance 100. That is, as shown in FIG. 3, the second cylindrical portion 120 and the third cylindrical portion 130 constitute an outer cylinder 151 b that covers the inner cylinder 151 a of the spray gun body 151. That is, the third cylindrical portion 130 corresponds to the outer surface of the outer tube 151b. As shown in FIG. 2, an outer surface of the second cylindrical portion 120 and an inner surface of the third cylindrical portion 130 can form a second space V ₂ through which a cooling medium flows. As described above, the second space V ₂ is communicated with the first space V ₁ in the nozzle portion 153. In the top-blowing lance 100 of this embodiment, as shown in FIG. 2, the cooling medium flows in from the upper side and from the first space V _{1 and} flows toward the nozzle portion 153, and then flows from the first space in the nozzle portion 153. V ₁ flows into the second space V ₂ and flows in the second space V ₂ from the front end side toward the upper side. The cooling medium is circulated in the first space V ₁ and the second space V ₂ to cool the top-blowing lance 100 and prevent the melting loss of the top-blowing lance 100.

In addition, since the top-blowing lance 100 is configured to be inserted from above the converter body 10, a sufficient length is required for insertion. Since the top-blowing lance 100 is set to a sufficient length for carrying out the blowing, the first cylindrical portion 110, the second cylindrical portion 120, and the third cylindrical portion 130 are manufactured by welding steel pipes. Therefore, the first cylindrical portion 110, the second cylindrical portion 120, and the third cylindrical portion 130 may have a welding portion 135 as shown in FIG. 4 (not shown in FIGS. 2 and 3). FIG. 4 is a schematic view schematically showing the vicinity of the outer tube 151b, and shows a state where the raw metal 7 is adhered to the welding portion 135 of the third cylindrical portion 130.

The welding portion 135 existing in the third cylindrical portion 130 is, as shown schematically in FIG. 4, mostly the starting point of the attachment of the raw metal 7. Therefore, in the top-blowing lance 100 of this embodiment, the details will be described later, as shown in FIG. 5, the covering portion 140 is provided so as to cover at least a part of the welding portion 135 that can be located in the converter body 10, and The coating portion 140 includes a predetermined metal element as a constituent element. This makes it possible to eliminate the state where the welding portion 135 that is the starting point of the adhesion of the raw metal 7 is exposed to the raw metal 7, and to suppress the adhesion of the raw metal 7 to the welding portion 135. In addition, since the coating portion 140 has a metal element that is difficult to adhere to the raw metal 7 as a constituent element, the raw metal 7 can be suppressed from reaching the coating portion 140 itself. In addition, even if the raw metal 7 is adhered to the covering portion 140, the raw metal 7 adhered to the covering portion 140 may fall off into the converter body 10.

When the top-blowing lance 100 is a sub-hole spray gun having a sub-hole, the following cases may be considered: the raw metal 7 is adhered to the outer surface of the outer cylinder 151 b of the main body 151 of the spray gun during blowing, and the sub-hole is Clogged. However, as shown in FIG. 5, a covering portion 140 is provided in order to cover at least a part of the welding portion 135 that can be located in the converter body 10, so that after the blowing is completed, the raw metal 7 will fall off to the converter each time it is charged. Inside the body 10. Thereby, there is no state in which the auxiliary hole is continuously blocked. As a result, since a bias flow does not occur on the oxygen jet flow discharged from the auxiliary hole, and the melting loss of the top-blowing lance 100 can be prevented, the life of the top-blowing lance 100 can be extended.

The covering portion 140 is provided on at least a part of the outer surface of the third cylindrical portion 130 in order to prevent adhesion of the raw metal 7 to the surface of the top-blowing lance 100. Therefore, the covering portion 140 is preferably provided so as to cover at least the welding portion 135 on the outer surface of the third cylindrical portion 130 inserted into the converter body 10. The details will be described later, and the covering portion 140 is formed of a covering material, and the covering material includes at least one of copper, nickel, and cobalt as a constituent element.

The nozzle portion 153 welded to the front end of the spray gun body portion 151 is preferably formed of copper with high thermal conductivity. The nozzle portion 153 is formed of copper having high thermal conductivity, and is cooled by a cooling medium such as water, so that the nozzle portion 153 can be easily radiated. This makes it possible to provide the nozzle portion 153 in a state where it is difficult to become a high temperature, and does not melt it even in a high temperature environment, and the durability of the top-blowing lance 100 can be improved. From the viewpoint that the nozzle portion 153 can be maintained in a cooled state, the state in which the raw metal is difficult to adhere during the blowing can also occur.

The main hole 102 is an opening of the nozzle portion 153 formed at the front end of the top-blowing lance 100, and is formed in the circumferential direction with one or a plurality of holes. The inside of the first cylindrical portion 110 and the outside can be communicated through the main hole 102, and the oxygen flowing through the first cylindrical portion 110 can be released to the outside through the main hole 102. The oxygen released from the main hole 102 is sprayed onto the molten pig iron 5 in the converter body 10, for example.

The top-blowing lance 100 has been described in detail so far. In addition, in FIG. 2 and FIG. 3, only the main hole 102 is described as a part of the top-blowing lance 100 that releases oxygen. However, the present invention is not limited to the example described above, and may include one or plural numbers, for example. Auxiliary holes (not shown) formed in the side surface portion of the spray gun body portion 151.

Next, the covering portion 140 formed on the outer surface of the third cylindrical portion 130 will be described in detail.

<Detailed description of the covering part 140>
(Formation position of the coating portion 140)
The covering portion 140 is at least a part of the outer surface of the third cylindrical portion 130 inserted into the converter body 10 as described above. In more detail, the covering portion 140 is preferably provided to cover the welding portion 135, wherein the welding portion 135 is at least a part of an outer surface of the third cylindrical portion 130 that can be positioned in the converter body 10.

The inventor of the present invention observed the used top-blowing lance 100 after the raw metal 7 was attached, and found that the raw metal 7 is easily attached to the third metal layer as shown in FIG. 4 in a schematic manner. The welding portion 135 of the cylindrical portion 130 and the welding portion 135 of the welding portion 135 existing between the third cylindrical portion 130 and the nozzle portion 153. The reason why the raw metal 7 is liable to adhere to the welded portion 135 is estimated by the inventors of the present invention as follows. That is, the emissivity ε with respect to the third cylindrical portion 130 is 0.7, and the emissivity ε of the welding portion 135 increases from 0.7 to 0.9, and it becomes easy to increase the surface temperature. As a result, it is presumed that the raw metal 7 tends to adhere to the welding portion 135.

In this manner, the raw metal 7 is likely to adhere to the welding portion 135 of the third cylindrical portion 130. FIG. 4 is a schematic view schematically showing a state where the raw metal 7 is adhered to the welding portion 135 existing in the third cylindrical portion 130. As shown in FIG. 5, the third cylindrical portion 130 includes a welding portion 135, and the covering portion 140 is formed to cover the welding portion 135. As described above, the covering portion 140 should preferably be provided so as to cover at least the welding portion 135 of the third cylindrical portion 130 and the welding portion 135 of the third cylindrical portion 130 and the nozzle portion 153 among the portions that can be positioned in the processing container. Any one welding portion 135. The covering portion 140 can be provided at the position as described above to suppress the adhesion of the raw metal 7 to the third cylindrical portion 130.

The position where the covering portion 140 is provided is not limited to the position of the welding portion 135 as described above, but may be formed at various positions of the third cylindrical portion 130. For example, the covering portion 140 may be formed to cover cracks or the like that may exist in the third cylindrical portion 130, or may be formed to cover various repair portions existing in the third cylindrical portion 130. The covering portion 140 may be formed to cover the entire third cylindrical portion 130. In addition, at least a part of the covering portion 140 to the nozzle portion 153 may be formed.

(Material of cover 140)
When the inventor of the present invention reviewed the long life and maintainability of the top-blowing spray gun 100, he thought of the following method: Use a material with corrosion resistance as a material to increase the life of the spray gun and reduce the frequency of maintenance work. Copper (Cu), nickel (Ni), and cobalt (Co), which are relatively low-cost compared to other metals, cover the surface of the top-blowing lance 100.

Therefore, the inventors of the present invention focused first on the thermal conductivity that is considered to be important for the long life of the top-blowing lance 100. This is because it is considered that if the thermal conductivity is larger, the surface of the top-blowing lance 100 can be rapidly cooled by the cooling medium flowing in the first space V ₁ and the second space V ₂ of the top-blowing lance 100 to prevent the raw metal 7 For the sake of fusing.

FIG. 6 shows the thermal conductivity of Cu, Ni, Co, and Fe, the main constituent materials of the top-blowing lance 100, and the cermet and ZrO ₂ used on the surface of the top-blowing lance 100. The thermal conductivity shown in FIG. 6 is a numerical value published in the literature, and is a value published in, for example, “Heat Transfer Engineering Materials compiled by the Japan Mechanical Society”. The thermal conductivity of Cu is about 400 W / mK, the thermal conductivity of Ni is 90 W / mK, and the thermal conductivity of Co is 100 W / mK. Compared with the thermal conductivity of Fe (approximately 40 W / mK), the thermal conductivity of these elements is formed to a large value. Therefore, the formation of the coating portion 140 including Cu, Ni, and Co having at least any one of them from Cu, Ni, and Co having a higher thermal conductivity than Fe makes it possible to suppress the adhesion of the source metal 7. In particular, Cu having a large thermal conductivity can remarkably obtain the effect of preventing the adhesion of the raw metal 7 formed by suppressing the rise in surface temperature. On the other hand, the cermet and ZrO ₂ used in the coating of spray guns have a lower thermal conductivity than Fe, which tends to increase the temperature, and it is considered that the adhesion of the raw metal 7 is reduced by suppressing the increase in surface temperature The effect will be smaller.

Next, when the inventors of the present invention reviewed the shedding mechanism of the raw metal 7 attached to the third cylindrical portion 130 during the blowing after the blowing, it was thought that the thermal expansion of the raw metal 7 and the third cylindrical portion 130 was mainly Factor.

In the blowing, although the top-blowing lance 100 is cooled by circulating the cooling medium in the first space V1 and the second space V2, the temperature of the outer surface of the third cylindrical portion 130 is about 150 ° C. So thermal expansion occurs. During the blowing, the raw metal 7 adheres to the outer surface of the third cylindrical portion 130 that is thermally expanding. After the blowing is completed, the temperature decreases, the third cylindrical portion 130 and the covering portion 140 shrink, and a gap is formed between the covering portion 140 and the raw metal 7 (hereinafter referred to as "air gap"). Since the covering portion 140 is made of a metal having a coefficient of linear expansion larger than that of the raw metal 7, the air gap formed during shrinkage becomes larger. As a result, it is considered that the raw metal 7 becomes easy to fall off from the surface of the coating portion 140 after the completion of the blowing. Then, the inventors of the present invention investigated the linear expansion coefficients of Cu, Ni, and Co formed by the difference between the temperature during and after the blowing.

The linear expansion coefficients of Cu, Fe, Ni, Co, cermet, and ZrO ₂ (zirconia) are shown in FIG. 7. The thermal expansion coefficient shown in FIG. 7 is a numerical value in the literature, and is a value published in, for example, the “Heat Transfer Engineering Materials compiled by the Japan Mechanical Society” or a value published by the manufacturer. Furthermore, in general, there is a temperature dependency on the physical property value. Regarding the linear expansion coefficient, however, the thermal expansion coefficient at 300K (normal temperature) is shown in FIG. 7 due to the low temperature dependence.

Here, since the raw metal 7 that is close to pure iron has a physical property value similar to that of carbon steel, if the linear expansion coefficient of carbon steel is regarded as the linear expansion coefficient of Fe, the coating portion 140 only needs to use the ratio Fe, which has a similar coefficient of linear expansion coefficient of 1.2 × 10 ^-6 [/ K], may be formed. From these viewpoints and referring to FIG. 7, it can be seen that Cu, Ni, and Co are examples of materials having a linear expansion coefficient larger than that of Fe. As described above, from the viewpoint of suppressing the adhesion of the source metal 7 formed by the air gap, Cu, Ni, and Co can be used for the coating portion 140. In particular, since the linear expansion coefficient of Cu is significantly larger than the linear expansion coefficient of Fe, it is more effective in suppressing the adhesion of the raw metal 7 using the air gap. On the other hand, since the linear expansion coefficient of cermet and zirconium dioxide is smaller than the linear expansion coefficient of Fe, the effect of suppressing the adhesion of the raw metal 7 formed by the air gap is small.

In addition, the inventor of the present invention believes that the coating portion 140 must be a substance that does not peel off from the third cylindrical portion 130 even if a temperature change is caused by a converter process performed repeatedly. Then, the inventors of the present invention investigated the thermal stress of Cu, Ni, and Co.

FIG. 8 shows the thermal stress generated on the steel tube when the temperature of the steel tube is set to 150 ° C. for each of the copper sprayed steel tube, the cermet sprayed steel tube, and the zirconia sprayed steel tube. The thermal stress shown in Figure 8 is a thermal transfer analysis using a commercially available thermal transfer analysis application, and the thermal expansion coefficient and rise are calculated for the two substances at the boundary of the sandwich shot (i.e., the steel pipe and the shot material). The thermal strain (linear expansion coefficient x rising temperature) multiplied by the temperature is calculated by multiplying the difference between the thermal strains of the two substances by the coefficient of elasticity.

In FIG. 8, the case where the thermal stress is a tensile stress with respect to the steel pipe is represented by a positive value, and the case where the thermal stress is a compressive stress with respect to the steel pipe is represented by a negative value. The copper shotgun steel pipe has a thermal stress of about -90 MPa and a compressive stress with respect to the steel pipe. Therefore, it is difficult to cause the peeling of the copper film in a high temperature state. On the other hand, in the cermet sprayed steel pipe, the cermet is easily peeled from the steel pipe because of the thermal stress acting in the tensile direction with respect to the steel pipe. In addition, although the zirconia molten shot steel pipe exerts thermal stress in the compression direction from the film to the steel pipe, the fine cracks in the zirconium dioxide film often cause stress concentration and are therefore prone to cracking. Therefore, for example, in the case of the copper coating portion 140, it is difficult for the coating portion 140 to peel and expose the outer surface of the third cylindrical portion 130, and the effect of suppressing the adhesion of the raw metal 7 can be maintained without peeling the coating portion 140. .

FIG. 9 is a graph showing the relationship between the thickness of the coating portion 140 using copper or nickel and the thermal stress generated in the third cylindrical portion 130. The thermal stress was analyzed by heat transfer with the coating thickness as a variable, and was determined by the same method as described above. As shown in FIG. 9, when the thickness of the coating portion 140 using copper is 40 mm, the thermal stress is about −100 MPa, and when the thickness of the coating portion 140 using nickel is 10 mm, the thermal stress is about −50 MPa. In any case, the thermal stress generated to the third cylindrical portion 130 is a compressive stress. Therefore, even when the thickness of the covering portion 140 is increased, peeling of the covering portion 140 is unlikely to occur.

As described above, the covering portion 140 of this embodiment is provided as a constituent element including at least any one of copper, nickel, and cobalt. Specifically, the coating portion 140 is provided in addition to the case where any one of copper, nickel, and cobalt is used as a single body, and also includes the case where an alloy composed of these elements is used, and the case where copper, nickel, or nickel is used. In the case of an alloy composed of at least one of cobalt and at least one of other elements.

When the material of the third cylindrical portion 130 is carbon steel, it may be considered that the surface temperature of the third cylindrical portion 130 is degraded due to CO gas generated during the blowing, and the surface temperature of the third cylindrical portion 130 is increased. It becomes easy to rise, and the raw metal 7 is fused. Therefore, it is possible to suppress the adhesion of the source metal 7 by forming the coating portion 140 with copper, nickel, and cobalt that are hardly deteriorated by CO gas.

(Thickness of the coating portion 140)
The thickness of the coating part 140 can be set in accordance with the degree of abrasion caused by the processing of the molten pig iron 5, the surface temperature of the coating part 140, the top-blown converter equipment used, and the like.

When the inventor of the present invention reviewed the abrasion of Cu caused by the processing of the molten pig iron 5 by the converter, it was confirmed that the abrasion thickness of the Cu after 300 times of the feeding process, which required replacement of the tuyere, was 300 μm. . Therefore, the thickness of the covering portion 140 may be such that the life of the covering portion 140 is not less than the life of the tuyere. For example, the lower limit of the thickness of the coating portion 140 when Cu is used may be set to 300 μm. The upper limit of the thickness of the coating portion 140 when Cu is used is preferably 500 μm from the viewpoint of cost. In this manner, the lower limit of the thickness of the coating portion 140 can be set in accordance with the abrasion resistance of the coating portion 140, the life of the tuyere and other devices constituting the converter, and the like.

Here, the ratio of the wear resistance of Fe, Ni, and Co to the wear resistance of Cu is shown in FIG. 10. The wear resistance ratio shown in FIG. 10 is a value obtained experimentally by performing an abrasion test. The results of the abrasion test are: the wear resistance ratio of Ni is 1.67, and the wear resistance ratio of Co is 2.73. Therefore, for example, when Ni is used for the coating part 140, the lower limit of the thickness of the coating part 140 can be set to 300 μm ÷ 1.67 to 180 μm according to the lower limit of the thickness when using Cu. The upper limit of the thickness of the coating portion 140 when Ni is used is preferably 200 μm. Similarly, when Co is used for the covering part 140, the lower limit of the thickness of the covering part 140 can be set to 300 μm ÷ 2.73 × 110 μm according to the lower limit of the thickness when using Cu. The upper limit of the thickness of the coating portion 140 when Co is used is preferably 150 μm.

In addition, as the thickness of the coating portion 140 is increased, the exposure of the outer surface of the third cylindrical portion 130 due to abrasion can be suppressed. However, if the covering portion 140 becomes too thick, the distance from the cooling medium to the surface of the covering portion 140 becomes longer, or the surface temperature of the covering portion 140 increases, and the raw metal 7 may adhere to the covering portion 140. . When the temperature of the outer surface of the third cylindrical portion is 175 ° C or higher, the raw metal 7 tends to adhere easily. Then, the inventor of the present invention calculated the temperature in each thickness of the coating portion 140 and the results obtained are shown in FIG. 11. The outer surface temperature was calculated by performing a heat transfer analysis using a commercially available heat transfer analysis application. FIG. 11 is a graph showing the relationship between the thickness of the covering portion 140 and the surface temperature of the covering portion 140.

As shown in FIG. 11, the coating portion 140 using Cu is about 175 ° C. at a thickness of 25 mm, and the coating portion 140 using Ni is about 175 ° C. at a thickness of 2 mm. That is, in a range of a thickness of copper of 25 mm or less or a thickness of nickel of 2 mm or less, the surface temperature of the coating portion 140 is 175 ° C. or less, and has a sufficient effect in suppressing the adhesion of the raw metal 7. Therefore, as long as the thickness of the covering part 140 can be adjusted according to the temperature in the converter body 10 or the distance between the molten pig iron 5 and the top-blowing lance 100, the thickness of the covering part 140 flows in the first space V ₁ and the second space V ₂ of the top-blowing lance 100. The processing conditions of the molten pig iron 5 such as the speed of the cooling medium may be appropriately set so that the surface temperature of the coated portion 140 becomes 175 ° C or lower. From the viewpoint of suppressing the adhesion of the raw metal, it is preferable to set the temperature to 175 ° C or lower. Set the thickness.

In addition, the upper limit of the thickness of the coating portion 140 may be set so that the top-blowing spray gun 100 can be taken out of the converter body 10 in consideration of the size of the furnace mouth 12 of the converter body 10 and the spray gun passage opening 22 of the exhaust hood 20.

In addition, the inventors of the present invention conducted further verifications for various factors in order to more reliably suppress the adhesion of the raw metal 7 to the coating portion 140. Next, in a practical operation using the top-blowing lance 100 provided with the coating portion 140, an example in which the raw metal 7 was attached to the coating portion 140 was observed. Therefore, for the top-blowing lance 100 before use and the top-blowing lance 100 after use, the surface roughness of the cover 140 before and after use is set to the arithmetic prescribed by JIS B0601: 2013. The average roughness Ra is measured. As a result, it was clear that the arithmetic average roughness Ra before use was about 7 to 8 μm, and the arithmetic average roughness Ra after use was about 7 to 9 μm. As a result, the inventor of the present invention determined that there is a possibility that the raw metal 7 may adhere to the coating portion 140 depending on the surface roughness of the surface of the coating portion 140.

Therefore, as a result of further verification using top-blown converter equipment in various places, it has been clearly known that in the top-blown converter equipment in which no adhesion of raw metal occurs, the coating portion 140 in the top-blown lance 100 The arithmetic average roughness Ra of the surface roughness is 3 μm or less. On the other hand, in the top-blown converter equipment where the adhesion of the raw metal has occurred, the arithmetic average roughness of the surface roughness of the coating portion 140 in the top-blowing lance 100 Ra is 15 μm. From the results of such verification, the inventors of the present invention have obtained the following knowledge: By making the arithmetic average roughness Ra specified in JIS B0601: 2013 of 3 μm or less on the surface of the coating portion 140, it is possible to further improve The adhesion of the raw metal 7 to the coating portion 140 is reliably suppressed.

Based on such knowledge and knowledge, in the top-blowing lance 100 of the present embodiment, it is preferable that the arithmetic average roughness Ra of the surface of the coating portion 140 specified in JIS B0601: 2013 is 3 μm or less. This makes it possible to more reliably suppress the adhesion of the source metal 7 to the coating portion 140. It should be noted that the smaller the arithmetic mean roughness Ra on the surface of the covering portion 140 is, the better, and the lower limit value is not particularly defined.

Here, the arithmetic average roughness Ra of the surface of the coating portion 140 can be measured along the tube axis direction or the tube peripheral direction of the top-blowing lance 100 by using a surface roughness measuring device according to JIS B0601: 2013. The surface of the covered part 140 of interest is specified.

The top-blowing lance 100 of this embodiment has been described in detail.

(Coating method of the top-blowing lance 100)
Next, a covering method (more specifically, a forming method of the covering portion 140) of the top-blowing lance 100 will be described.

The coating method of the top-blowing spray gun of this embodiment is a coating method of a water-cooled top-blowing spray gun including a spray gun main body portion and a nozzle portion provided at the front end of the spray gun main body portion. In some cases, the coating material includes at least any one of copper, nickel, and cobalt as a constituent element. That is, in the coating method of the top-blowing lance of this embodiment, a coating material containing at least any one of copper, nickel, and cobalt is used as a constituent element. At least a part of the surface is covered. By forming the coating portion 140 by the coating method described above, it is possible to suppress the adhesion of the raw metal to the outer surface of the spray gun body portion.

As mentioned above, when covering at least a part of the surface of the third cylindrical portion 130, it is preferable to cover at least a part of the surface of the third cylindrical portion 130 to the coated surface according to JIS B0601: 2013. The predetermined arithmetic average roughness Ra is 3 μm or less. This makes it possible to more reliably suppress the adhesion of the source metal 7 to the coating portion 140.

The method of coating the surface of the third cylindrical portion 130 using a coating material containing at least any one of copper, nickel, and cobalt as a constituent element is not particularly limited, and various known coating methods can be appropriately used. Examples of such a coating method include construction methods such as thermal spraying, surfacing, and plating.

It should be noted that the position of the covering portion formed by the covering material or the final thickness of the covering material in the third cylindrical portion 130 is as described above.

The details of the method of forming the coating portion 140 by spraying are not particularly limited as long as the effect of suppressing the adhesion of the raw metal 7 can be obtained on the coating object on the outer surface of the third cylindrical portion 130. For example, as long as a known spraying device can be used to spray the coating material as described above on the surface of the third cylindrical portion 130 where the coating portion 140 is to be formed, it can be easily implemented from the viewpoint of coating equipment. .

Here, the surface of the third cylindrical portion 130 where the coating portion 140 is to be formed may be subjected to pretreatments such as cleaning, roughening, masking, and thermal spraying as needed. Cleaning can also be performed by chemical cleaning methods such as erasing and washing, dipping washing, spray washing using solvents, acidic cleaning agents, and alkaline cleaning agents, or by sandblasting, ultrasonic cleaning, It is implemented by a physical cleaning method such as a high-pressure liquid ejection method. The roughening may be performed on the outer surface of the third cylindrical portion 130 by sandblasting or the like. In addition, in order to prevent the oxidation of the surface of the third cylindrical portion 130 or to improve the adhesion with the coating portion 140, it is also possible to perform a base shot by using a Ni-Al alloy or the like in accordance with need.

In the case where the coating portion 140 is formed by thermal spraying, it is desirable to perform mechanical processing (for example, performing a grinding process or a grinding process) on the portion covered by the coating material so that the arithmetic average roughness Ra of the surface becomes 3 μm or less. When machining is performed, it may be appropriate to consider the existence of a coating material removed by machining, and to first cover the coating material to be thicker than a desired final thickness.

In addition, as for the details of the method of forming the coating portion 140 by plating, as long as the effect of suppressing the adhesion of the raw metal 7 can be obtained on the coated object on the outer surface of the third cylindrical portion 130, and It is not particularly limited, and can be suitably applied to fusion plating, vapor phase plating, electric plating, chemical plating, etc., depending on the workability, the type of coating metal, and the like.

In addition, as for the details of the method of forming the coating portion 140 by overlay welding, it is only necessary to obtain the effect of suppressing the adhesion of the raw metal 7 to the coated object on the outer surface of the third cylindrical portion 130, and It is not particularly limited, and various known overlay welding methods can be applied.

In addition, in the above-mentioned construction methods of spraying, plating, and overlay welding, since the thermal influence on the third cylindrical portion 130 can be reduced, it is possible to suppress the occurrence of bending over the entire length. From a viewpoint, it is more preferable to use a formation method by spraying. In addition, by using the formation method by spraying, it is possible to more easily achieve a fine coating state that can withstand the above-mentioned machining. Therefore, from the viewpoint of workability, it is also possible to use spraying. The formation method is preferably performed.

The covering method of the top-blowing lance of this embodiment has been described above.

(to sum up)
As described above, in the top-blowing lance and the coating method of the top-blowing lance of this embodiment, the outer surface of the third cylindrical portion 130 in the lance main body 151 has at least one of copper, nickel, and cobalt. As a covering portion covered with the covering metal as a constituent element, adhesion of the raw metal 7 to the third cylindrical portion 130 can be suppressed.

In addition, since the raw metal 7 attached to the third cylindrical portion 130 can fall off each time the material is fed, it is possible to reduce the number of trimming work of the raw metal 7 to remove the raw metal 7 attached to the spray gun body portion 151 after the blowing is completed. In addition, since the adhesion of the raw metal 7 to the top-blowing lance 100 can be prevented, the yield can be improved.
[Example]

(Experimental example 1)
When at least a part of the surface of the third cylindrical portion 130 is polished, the number of blows before the trimming of the raw metal is investigated for each of the case where copper is sprayed and the case where ceramics are sprayed. Since it was considered that the temperature of the outer surface of the third cylindrical portion 130 may change greatly depending on the state of the outer surface before the survey, the outer surface of the third cylindrical portion 130 was investigated due to the difference in emissivity. Surface temperature. For example, when the third cylindrical portion 130 is finely polished to have gloss, its emissivity will be small, and the temperature rise due to radiation will be small. However, if the outer surface is deteriorated due to abrasion during blowing and CO gas, etc., since the emissivity becomes large and the surface temperature becomes high, it can be considered that the raw metal 7 becomes easily fused.

FIG. 12 is a graph showing a difference in temperature of the third cylindrical portion 130 due to emissivity. Here, each temperature was calculated using a commercially available heat transfer analysis application Fluent, and the heat transfer analysis was performed with the emissivity ε as a variable. As a result, the temperature of the outer surface of the third cylindrical portion 130 when the emissivity ε was 0.7 was 150 ° C. On the other hand, when the emissivity ε is 0.9, the temperature of the outer surface of the third cylindrical portion 130 becomes about 175 ° C, which is higher than the case where the emissivity is 0.7. The temperature of the coated portion 140 using copper is 150 ° C., which is the same as that of the steel pipe when the emissivity ε is 0.7. Copper is difficult to deteriorate on the surface, and copper is hardly deteriorated due to CO gas generated during the smelting. Therefore, it is difficult to increase the emissivity. Therefore, it became clear that the adhesion of the source metal 7 can be suppressed by using copper in the coating portion 140. In addition, nickel and cobalt have the same effect of suppressing deterioration as copper, and can be calculated similarly.

The outer surface of the third cylindrical portion 130 of the top-blowing lance 100 and the polished surface are based on the number of blows before the raw metal is trimmed using the top-blowing lance 100 manufactured from a conventional steel pipe. The ratio of the number of blows before the trimming of the raw metal is calculated for each of the conditions of the case of molten copper and the case of molten metal. The obtained results are shown in FIG. 13. FIG. 13 shows a normalized value by setting the conventional number of blows to 1. The surface grinding spray gun is a spray gun that has been polished. The copper spray gun is a spray gun that sprays copper to provide a coating portion 140 with a thickness of 300 μm. The ceramic spray gun sprays a zirconium dioxide to provide a coating portion 140 with a thickness of 300 μm. Spray gun.

Compared with the conventional top-blowing lance 100, the top-blowing lance 100 having the coating part 140 using copper has 10 times the number of blows before trimming the raw metal 7 attached to the lance main body 151. On the other hand, with respect to the top-blowing lance 100 that has been surface-polished and the top-blowing lance 100 having the coating portion 140 formed by ceramic melting shot, the number of blows has been doubled and 1.8 times, respectively.

The coating portion 140 using copper has been confirmed to have a significant effect compared to surface polishing and ceramic spraying. The reason for this may be that the surface-blown top-blowing lance 100 deteriorates the surface and adheres to the raw metal 7 as the blowing is repeated, and as the number of blowing increases, the raw material is promoted in the adhered portion. Accumulation of metal 7. In addition, it is conceivable that the top-blowing lance 100 having the coating portion 140 formed by ceramic spraying may rupture and peel the coating portion 140 due to stress concentration, and deposit and deposit the raw metal 7 on the peeling portion. Since the coating portion 140 using copper progresses slowly, a sufficient adhesion suppressing effect of the raw metal 7 is obtained. It is conceivable that when the covering portion 140 uses nickel or cobalt and the thickness of the covering portion 140 is set to 200 μm and 150 μm, respectively, the effect of suppressing the adhesion of the raw metal 7 and the case where copper is used to form the covering portion 140 with a thickness of 300 μm The effect is the same.

(Experimental example 2)
In order to further verify the knowledge and insights obtained in Experimental Example 1, the inventors of the present invention used a general-used top-blowing spray gun with a carbon steel spray gun outer cylinder, and changed various conditions from the blowing ratio and The viewpoint of bending with respect to the full length was verified.

Here, as a coating material for forming a coating portion, a coating material using Cu as a constituent element, a coating material using Ni as a constituent element, a coating material using Co as a constituent element, and a ceramic coating material are prepared. Moreover, as a coating method of a coating material, it is set to use either spraying or overlay welding.

The shot is ground by machining to an amount equivalent to the thickness of the formed coating portion, and then the coating material is shot into the shot portion (ie, the portion where the coating portion is formed) by flame spraying. As the coating material, powdered copper is used in the case of copper coating, powdered nickel is used in the case of nickel coating, powdered cobalt is used in the case of cobalt coating, and powdered ceramic is used in the case of ceramic coating. After the shot, the resulting surface was ground to be flat.

The surfacing welding is to preheat the surfacing part to about 500 ° C., and use a TIG welding machine to melt the TIG welding rod (JIS Z3341 YCu) while melting, and then grind the surface to be flat after cooling.

For each of the obtained top-blowing lances, the arithmetic average roughness of the coating portion was measured in the direction of the tube axis using the FormTalysurf Series 50mm Intra2 manufactured by Taylor Hobson Company in accordance with JIS B0601: 2013 in accordance with the method described previously. Degrees Ra.

In addition, in order to investigate the difference in thermal influence caused by the different coating methods, the following verification was performed to determine whether the bending is less than the allowable value (0.3%) with respect to the total length. Specifically, the bending of each of the obtained top-blowing lances was measured as follows, and the magnitude of the obtained bending was compared with the allowable value.

Here, the measurement sequence of the bending of the top-blowing lance is as follows.
First, the top-blowing spray gun is set visually to measure the direction of large bending. Thereafter, a line was drawn visually from the direction of the curved depression with respect to the tube axis direction of the top-blowing spray gun, and the length L0 of the spray gun was measured. The distance from the line to the spray gun was measured at three or more points in the middle, and the maximum distance among the three or more obtained distances was set to L1. In this case, the curvature of the top-blowing lance of interest is L1. Using the obtained measured values L0 and L1, a ratio (L1 / L0) was calculated, and the obtained ratio was expressed in percentage notation.

When the obtained ratio is less than the allowable value (0.3%), it is judged as the score "A", and when the obtained bending exceeds the allowable value, it is judged as the score "B".

In addition, each of the obtained top-blowing lances was used in the operation of the same top-blowing converter equipment, and the blowing ratio was calculated. The blow ratio is based on the number of blows before the trimming of the raw metal in the case of using the top blow lance of Comparative Example 1 which is not provided with a coating part. The number of blows is normalized.

The number of blows before the metal trimming is performed before the weight of the metal after the metal trimming becomes necessary to be 2 tons or more, or when the diameter of the metal is about 1.1 times the diameter of the spray gun. number.

The obtained results are shown together in Table 1 below.

[Table 1]
Table 1

As is clear from Table 1 above, in the top-blowing lance (Example 1 to Example 7) provided with a coating portion of the present invention, the blowing ratio is significantly improved. It is considered that this is because the life of the top-blowing lance is prolonged because the adhesion of the raw metal has been suppressed. In addition, when comparing Example 1 and Example 6, and Example 2 and Example 7 respectively, it can be clearly understood that the arithmetic mean roughness Ra of the coating portion is 3 μm or less, and the number of blows is surely made. Better than that. In addition, it has been confirmed that when the shot is selected as the coating method, compared with the case where the overlay is selected, the bending with respect to the entire length can be made less than the allowable value, and the heat effect can be suppressed by using the shot. .

On the other hand, in Comparative Example 2 using ceramics as the coating material, the ratio of the number of blows did not exceed 1.1, and the adhesion of the raw metal could not be prevented.

As mentioned above, although the preferred embodiment of this invention was described in detail with reference to drawings, this invention is not limited to the said example. As long as it is a person with ordinary knowledge in the technical field to which the present invention belongs, it is obvious that various modifications or amendments can be conceived within the scope of the technical ideas described in the scope of patent application. It is understood to belong to the technical scope of the present invention.

For example, in the above-mentioned embodiment, the top-blowing spray gun of the converter equipment was described, but the present invention is not limited to the above-mentioned examples. For example, the top-blowing lance of the present invention can also be applied to other than converter equipment. For example, it can be used as a smelting reduction process in a melting furnace, a molten pig iron preparation process in a torpedo car, and a secondary refining using a vacuum furnace. To use the spray gun used in this. Moreover, in the said embodiment, although the top-blowing lance which sprayed oxygen from the top of the molten pig iron in the top-blowing converter facility was demonstrated as an example, this invention is not limited to the said example. For example, this technique is also applicable to an immersion spray gun used for immersion in molten pig iron.

5‧‧‧ molten pig iron

7‧‧‧ raw metal

9‧‧‧ slag

10‧‧‧Converter body

11‧‧‧Top blowing spray gun

12‧‧‧furnace mouth

20‧‧‧Exhaust hood

22‧‧‧ spray gun through the mouth

100‧‧‧Top Blow Gun

102‧‧‧Main hole

110‧‧‧The first cylindrical part

120‧‧‧ 2nd cylindrical section

130‧‧‧ the third cylindrical part

135‧‧‧ Welding Department

140‧‧‧ Covered Department

151‧‧‧Brush body

151a‧‧‧Inner tube

151b‧‧‧Outer tube

153‧‧‧Nozzle

V ₁ ‧‧‧First Space

V ₂ ‧‧‧ 2nd space

FIG. 1 is a schematic explanatory diagram showing a schematic configuration of a top-blown converter equipment using a top-blown lance 100 according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a schematic configuration of the top-blowing lance 100 according to the same embodiment.

FIG. 3 is an explanatory diagram showing the components of the top-blowing lance 100 according to the embodiment.

FIG. 4 is an explanatory diagram showing an example of a case where the raw metal 7 is attached to the top-blowing lance 100.

FIG. 5 is a schematic diagram showing the vicinity of the third cylindrical portion 130 of the top-blowing lance 100 of the same embodiment.

FIG. 6 is a diagram showing a graph of a thermal conductivity of a material that can be used as a material of the covering portion 140.

FIG. 7 is a graph showing a linear expansion coefficient of each material.

FIG. 8 is a graph showing a thermal stress applied to the outer surface of the third cylindrical portion 130.

FIG. 9 is a graph showing the wear resistance of copper, iron, nickel, and cobalt.

FIG. 10 is a graph showing a relationship between the thickness of the covering portion 140 and the temperature of the surface of the covering portion 140.

FIG. 11 is a graph showing the relationship between the thickness of the coating portion 140 and the thermal stress.

FIG. 12 is a graph showing a graph of the outer surface temperature and the inner surface temperature of the cylinder outside the surface of the steel pipe and the surface of the copper-sprayed steel pipe.

FIG. 13 is a graph showing a ratio of the number of blows before the raw metal trimming is performed in each surface treatment of the outer surface of the third cylindrical portion 130.

Claims (16)

A top-blowing spray gun is a water-cooled top-blowing spray gun and has: Spray gun body A nozzle portion provided at a front end of the spray gun body portion; and The covering portion is provided with respect to at least a part of the outer cylinder of the spray gun body portion, and contains at least any one of copper, nickel, and cobalt as a constituent element. For example, the top-blowing spray gun of claim 1, wherein the arithmetic average roughness Ra of the surface of the aforementioned coating portion as specified in JIS B0601: 2013 is 3 μm or less. The top-blowing spray gun according to claim 1 or 2, wherein the coating portion is provided in the outer cylinder at least a part of a surface that can be located inside the processing container. The top-blowing spray gun according to any one of claims 1 to 3, wherein the coating portion is a welding portion provided to cover at least a part of the outer cylinder among portions that can be positioned in the processing container. The top-blowing spray gun according to any one of claims 1 to 4, wherein the covering portion is formed using copper, and the thickness of the covering portion is 300 μm or more. The top-blowing spray gun according to any one of claims 1 to 4, wherein the covering portion is formed using nickel, and the thickness of the covering portion is 180 μm or more. The top-blowing spray gun according to any one of claims 1 to 4, wherein the coating portion is formed using cobalt, and the thickness of the coating portion is 110 μm or more. A coating method for a top-blowing spray gun is a coating method for a water-cooled top-blowing spray gun including a spray gun main body and a nozzle portion provided at a front end of the spray gun main body. And at least a part of the coating material, the coating material includes at least any one of copper, nickel, and cobalt as a constituent element. If the coating method of the top-blowing lance of claim 8 is to coat at least a part of the outer cylinder, the arithmetic average roughness Ra of the coated surface shall be 3 μm or less in accordance with JIS B0601: 2013. The coating method of the top-blowing spray gun according to claim 8 or 9, wherein at least a part of the outer cylinder is coated by spraying, surfacing, or plating the coating material. For example, the coating method of the top-blowing spray gun of claim 10, wherein at least a part of the outer cylinder is covered by spraying the coating material, In addition, a coating portion formed of the coating material is machined such that the arithmetic average roughness Ra of the surface is 3 μm or less in accordance with JIS B0601: 2013. The coating method of the top-blowing lance according to any one of claims 8 to 11, wherein the coating site formed by the aforementioned coating material is at least a part of a surface in the aforementioned outer cylinder that can be positioned inside the processing container. The coating method of the top-blowing lance according to any one of claims 8 to 12, wherein the coating site formed by the aforementioned coating material is a welded portion that is present in at least a part of the outer cylinder among the parts that can be positioned in the processing container. According to the coating method of the top-blowing spray gun according to any one of claims 8 to 13, a coating material using copper as a constituent element is used as the coating material, and the coating material is coated to a final thickness of 300 μm or more. According to the coating method of the top-blowing spray gun according to any one of claims 8 to 13, a coating material using nickel as a constituent element is used as the coating material, and the coating material is coated to a final thickness of 180 μm or more. According to the coating method of the top-blowing spray gun according to any one of claims 8 to 13, a coating material using cobalt as a constituent element is used as the coating material, and the coating material is coated to a final thickness of 110 μm or more.