JP6308787B2 - Lance pipe - Google Patents

Description

  The present invention relates to a lance pipe used in a refining process of molten steel, molten iron, molten metal and the like.

  A hollow tubular lance pipe in which a gas such as oxygen or argon or other molten metal treating agent is blown into a molten metal melt is widely known.

  The lance pipe is provided with a metal-made long circular tubular cored bar and a refractory layer (hereinafter referred to as castable) covering the outer peripheral surface of the cored bar. In addition to the straight lance pipe, there are curved lance pipes having a substantially J-shaped or L-shaped side view. As the refractory, alumina-silica low cement castable or the like is used.

  The above-described curved tubular lance pipe is used by immersing a curved portion at the tip in a molten metal. Since the metal bath water is hot, the heat of the bath water is conducted to the core metal through the castable. Since the thermal expansion coefficient of the cored bar is larger than that of the castable, the cored bar seems to exert stress on the castable while thermally expanding, and it is considered that a crack occurs in the castable. Cracks further expand with increasing temperature during use of the lance pipe. As a result, the castable is peeled off and dropped, the temperature of the core metal rises to such an extent that it melts, and the lance pipe cannot be used.

  Therefore, in order to increase the durability of use of the lance pipe, there has been a method in which a netting material is wound around a metal core and the castable is held by the netting material to prevent the castable from peeling off or falling off.

  However, even with the conventional netting material, the castable cannot be completely peeled off or dropped out, which is insufficient from the viewpoint of durability.

  In addition, the lance pipe in use is subjected to various forces such as a reaction force action caused by blowing a gas such as oxygen and a bath water treatment agent, and vibration of the hot metal. Curved tubular lance pipes have the problem that they are easily affected by the force applied to the curved curved pipe part immersed in the bath water, and the damage on the side where the radius of curvature of the curved pipe part is large is particularly severe. It was.

  The present invention has been made in view of the above-described circumstances, and provides a lance pipe having higher durability. In addition, a lance pipe that is realistically appropriate from the viewpoint of improving the efficiency of productivity is provided. The issue is to provide.

In order to solve the above-mentioned problems, a lance pipe according to the present invention according to claim 1 is a metal and tubular cored bar having a straight pipe part and a curved pipe part that is curved and extended from the straight pipe part. And a refractory layer covering the outer peripheral surface of the metal core , and a lance pipe that supplies the molten metal treatment agent to the molten metal, and is fixed to only the outer surface having a large radius of curvature of the curved pipe portion. A plurality of studs and a net member wound around the core metal are provided, and the plurality of studs and the net member are embedded in the refractory layer .

  The lance pipe of the present invention includes a metal core, a refractory layer, and a plurality of studs. The metal core is made of a metal and has a tubular shape having a straight pipe portion and a curved pipe portion that is curved and extended from the straight pipe portion. The curved pipe portion includes a tube whose tip side is a nozzle, a tube whose tip side is further extended in a straight tube shape like an L shape, and the like. The refractory layer is made of an alumina-silica low cement castable or the like. The core metal and the refractory layer are the same as the core metal and the refractory layer of a conventional lance pipe having a substantially J-shape or L-shape in a side view.

  The stud includes a base end portion such as a substantially V shape, a Y shape, and a T shape, and a tip end portion that extends from the base end portion and widens. The base end portion of the stud is usually fixed by spot welding or the like to the core metal. The front end of the stud is embedded in the refractory layer and integrated.

In the lance pipe of the present invention, a plurality of studs are fixedly spaced only on the outer surface having a large radius of curvature of the bent portion of the cored bar . The use of a large number of studs increases the effect of increasing the durability of the lance pipe, but increases the working time and costs. Considering the tradeoff between increased durability and increased cost, the stud is provided only on the outer surface where the radius of curvature of the bent portion of the cored bar is large .

  The lance pipe is manufactured by, for example, covering a core metal and a stud fixed to the core metal with a castable to form a refractory layer and embedding in the refractory layer. The tip of the stud embedded inside the refractory layer works as an anchor and is integrated with the refractory layer, so that the stud is prevented from coming off from the refractory layer.

  Further, as described above, the curved tubular lance pipe is used by immersing the curved curved pipe portion in the molten metal. In fact, the damage on the side where the radius of curvature of the curved pipe portion is large may be particularly severe. Although known, the following causes are considered.

  In high-temperature hot molten metal, the difference in thermal expansion coefficient is more pronounced between the metal cored bar and the refractory layer made of castable containing silica, etc. Some are due to the difference.

  For example, a curved pipe portion of a substantially L-shaped core consists of a large-diameter side curved pipe portion with a large curvature radius and a small small-diameter side curved pipe portion, and the arc length is larger on the large-diameter side than on the small-diameter side. The longer part becomes longer along the axial direction. Since both the large-diameter side and the small-diameter side have the same metal core, they have the same linear expansion coefficient, and the large-diameter side has a longer actual length that changes by extending the length before expansion. It is considered to be. Therefore, the tensile stress exerted on the refractory layer by the thermal expansion of the core metal can be larger on the large diameter side. Cracks are likely to occur in the refractory layer of the part, and peeling and dropping are likely to occur.

  Moreover, the above-mentioned large diameter side has a larger volume and weight of the entire refractory layer covering the cored bar corresponding to the longer arc length. Further, unlike the inner side, there is no pipe wall of the core metal that cancels out the refractory layer falling toward the bottom of the molten metal container. In combination with the action of the force caused by the vibration of the hot metal due to the injection of gas or the like described above, there is a conceivable cause that a larger gravity acts on the large diameter side than on the small diameter side.

Here, since the stud is fixedly spaced only on the outer surface where the radius of curvature of the bent portion of the cored bar is large , the stud is fixed rather than fixed over the entire length of the cored bar. It is possible to save labor in welding to the core. In addition, durability performance can be ensured while intensively handling the parts that are most likely to cause the castable peeling and dropping.

In the lance pipe of the present invention, the stud is fixed only on the outer surface of the curved pipe portion where the radius of curvature is large . Here, the outer surface refers to the outer peripheral surface of the cored bar. The inner surface refers to the inner peripheral surface of the cored bar. Moreover, a large curvature radius means the centrifugal direction side of a curved pipe part.

According to the present invention, the castable part of the lance pipe can be effectively prevented from being peeled off and dropped off by performing only the minimum work of welding the stud only to the outer surface where the radius of curvature of the bent pipe part of the metal core is large. it can. Therefore, when it is highly desired to improve the production efficiency of the lance pipe while demanding higher durability, the most appropriate one can be provided.

The lance pipe according to the present invention is further adjacent to the outer surface of the bent pipe portion to which the stud is fixed, the outer surface of the bent pipe portion to which the stud is fixed, and the bent pipe portion of the straight pipe portion. A net member is wound around the outer surface portion and embedded in the refractory layer. Since the mesh material extends two-dimensionally, it can be fixed to the core metal by winding it around the outer surface of the core metal. Moreover, a large area can be covered. Furthermore, since the mesh material is easily integrated into the refractory layer, the resistance to separation from the refractory layer is great.

According to the present invention , the most appropriate lance pipe can be provided in the case where it is strongly desired to improve the durability while demanding the production efficiency of the lance pipe.

  As described above, the tip end portion of the stud has an anchoring action, and the refractory layer is prevented from being peeled off and dropped off by the engaging action based on the anchoring action. Since a plurality of studs are welded to the cored bar at intervals, the studs are prevented from falling off at each discontinuous welding point.

  Here, unfortunately, even if there is a crack in the part where the stud is not fixed, each stud continues in a planar shape via a mesh material such as a wire mesh to suppress the expansion of the crack, and the refractory layer Peeling and falling off can be prevented, and the durability of the lance pipe can be greatly improved.

  According to the present invention, it is possible to provide a highly reliable lance pipe after realistically considering the balance between improvement in productivity efficiency and improvement in use durability.

It is sectional drawing of the lance pipe of Embodiment 1 which shows a use condition simply. FIG. 2 is an enlarged cross-sectional view of a bent pipe portion in the lance pipe of FIG. (A) _{Y 1} -Y 1 line end view of the lance pipe 2, a _(b) Y 2 -Y _2-wire end view. It is explanatory drawing which shows typically engagement with the stud and net | network material in the curved pipe part of a metal core in a cross sectional view. It is explanatory drawing which shows typically engagement with the stud and net | network material in the curved pipe part of a metal core in the X direction view. About the lance pipe of 2nd Embodiment, it is sectional drawing which shows the arrangement | positioning relationship by which a net | network material is wound around a metal core, and a stud is fixed.

The following describes the lance pipe L ₁ of the first embodiment. 1 is a cross-sectional view of the lance pipe according to the first embodiment showing the state of use in a simplified manner, FIG. 2 is a cross-sectional view in which a curved pipe portion is enlarged in the lance pipe of FIG. 1, and FIGS. Y ₁ -Y ₁ line in FIG. 2, respectively of the lance pipes, Y ₂ -Y _2-wire end view, Figure 4 shows schematically in cross section the engagement between the stud and the network material in the bend portion of the core It is explanatory drawing.

Lance pipe L ₁ is a substantially L-shape and a curved pipe portion 13 extending from the straight pipe portion 12 and the straight pipe section 12, the core of a substantially L-shaped elongated circular tube made of metal A gold 2 and a castable 3 that covers the outer surface of the core 2 are provided. In addition, as will be described later, a plurality of Y-shaped studs 41 are fixed to the large-diameter outer surface 231 a of the bent tube portion 23 of the core metal 2, and the metal mesh 5 is wound around the outer surface 231.

The core metal 2 is provided with a straight pipe portion 22 of the full length l ₁ extending linearly from the inlet 21 to the gas or the like is introduced, and a curved pipe portion 23 that extends curved from the straight pipe section 22 . The curved pipe portion 23 is a portion extending from the curved proximal end portion 232 to the distal end discharge portion 233 serving as a gas discharge port. The curved pipe portion 23 includes an arc portion 234 that forms an arc having a central angle θ in a cross-sectional view along the central axis direction H, and a straight straight portion 235 (total length l ₂₂ ). In FIG. 1, the arc length of the arc portion 234 is indicated as l ₂₁ for convenience.

A plurality of Y-shaped studs 41 are provided on the outer surface 231 of the curved pipe portion 23 of the cored bar 2 and on the large-diameter outer surface 231a on the side of the curved portion 23 where the radius of curvature of the arc portion 234 is large (r ₁ ). Is installed. The stud 41 is attached by welding both open arms 41a at the front end to the outside in the radial direction and welding the base 41b to the large-diameter outer surface 231a. The plurality of studs 41 are arranged in three rows along the circumferential direction of the large-diameter outer surface 231a, and have a large diameter from the large-diameter curved proximal end portion 232a where the core metal 2 starts to bend along the axial direction H. It is attached to the part reaching the tip discharge part 233a. More specifically, in the use state of the lance pipe L ₁ , the axial direction extends from a portion where the curve is slightly advanced from the curved base end portion 232 to a portion slightly ahead from the distal end discharge portion 233 to a portion arranged directly below the vertical direction. One row is attached along H at a predetermined interval. In addition, two rows are attached along the circumferential direction with a center angle of about 45 degrees on the left and right with the one row as the center, for a total of three rows.

  A wire mesh 5 is wound around the outer surface 231 of the bent tube portion 23 of the core metal 2. As a result, in the large-diameter outer surface 231a to which the stud 41 is attached, the tip end portion of the locking open arm portion 41a of each welded stud 41 is locked in place with the iron wire 51 of the wire mesh 5. Yes.

  The castable 3 is made of a ceramic refractory. It is a slurry-like refractory material having fluidity containing a binder (inorganic binder or organic binder). The outer surface of the metal core 2 is covered over the entire length and dried and solidified in that state.

  The castable 3 has a sufficient thickness t so that the studs 41 and the wire mesh 5 locked to the studs 41 are embedded in the large-diameter outer surface 231a of the bent pipe portion 23 so that they are not exposed to the outside of the castable 3. have. In addition, the lance pipe L is formed in a substantially similar size to the core metal 2 because it has a uniform thickness t over the entire length of the core metal 2. The castable 3 is also filled in an anchor portion 41 c (a portion close to the large-diameter outer surface 231 a of the core metal 2) formed on the lower side of the locking open arm portion 41 a of the stud 41.

Next, the usage state of the lance pipe according to the first embodiment will be described. In FIG. 1, the lance pipe L ₁ is used by immersing a curved pipe portion 13 having a discharge port 14 in a liquid of molten metal M accommodated in a container N. A gas or the like (not shown) is blown from the introduction port 11. The “gas” refers to oxygen gas for causing an oxidation reaction in the molten metal M, a medium for transporting the molten metal treatment agent, or an argon gas blown for stirring or temperature control of the molten metal M or the like. An active gas and nitrogen gas can be illustrated. The blown gas is discharged into the molten metal M from the discharge port 14 (tip discharge portion 233) via a flow path formed in the hollow portion of the cored bar 2.

Here, curved pipe portion 13 which is immersed in the molten metal M of the lance pipe L ₁ in use is a portion that receives a large force due to vibration and anti-force action for or hot metal by gas introduction. The bent tube portion 13 corresponds to a bent tube covering layer 33 in which the outer surface 231 of the bent tube portion 23 of the core metal 2 is covered with a castable 3.

  Further, below the large-diameter outer surface covering layer 331a on the side curved to a large diameter in the curved pipe covering layer 33 of the castable 3, the covering layer 331a is peeled off and dropped off, and the bottom of the container N of the molten metal M is removed. There is no tube wall that forms the large-diameter outer surface 231a of the cored bar 2 that cancels out the settling toward the surface. Therefore, the gravity caused by the vibration or the like becomes larger than that in the case of the small-diameter outer surface coating layer 331b.

  Further, in the arc portion 234 of the cored bar 2, the arc diameter of the large-diameter arc surface 234a is longer than that of the small-diameter arc surface 234b. These large-diameter or small-diameter arc surfaces 234a and 234b are covered with the large-diameter or small-diameter arc surface covering layers 334a and 334b of the castable 3, respectively. Due to the difference in arc length, the large diameter side coating layer 334a has a larger volume and weight. Therefore, gravity acts on the large-diameter outer surface coating layer 331a in the curved pipe coating layer 33 more than the small-diameter outer surface coating layer 331b.

  At the same time, when the gas is blown out of gas, a part of the components contained in the molten metal M undergoes an oxidation reaction to generate heat, and even the temperature of the hot molten metal M further rises and is castable. Heat is transferred to the cored bar 2 through 3, and the castable 3 and the cored bar 2 expand at different thermal expansion rates. The large-diameter outer surface 231a expands more than the small-diameter outer surface 231b due to the length of the arc length of each of the large-diameter or small-diameter arc surfaces 234a, 234b of the curved pipe portion 23 of the cored bar 2. It is thought that the actual length that expands (extends) by the length of the previous original arc length increases. Therefore, the tensile stress exerted on the bent pipe covering layer 33 of the castable 3 by the thermal expansion of the bent pipe portion 23 increases toward the large-diameter outer surface covering layer 331a as the difference in expansion length increases as the temperature further increases. It is considered that the crack C is likely to occur in the coating layer 331a.

  Here, a plurality of Y-shaped studs 41 are welded to the large-diameter outer surface 231a of the cored bar 2 at predetermined intervals. The stud 41 holds the castable member 3 filled in the anchor portion 41c from the large-diameter outer surface 231a and keeps it in the molten metal M by the locking open arm portion 41a. That is, in particular, peeling and dropping of each stud 41 at each welding point described above in the large-diameter outer surface coating layer 331a of the curved pipe coating layer 33 is effectively prevented (see FIG. 4).

Further, the tip end portion of the locking open arm portion 41 a of each stud 41 is locked in place with the iron wire 51 of the wire mesh 5, and each stud 41 is connected to the outer surface on the large diameter side of the core metal 2 through the wire mesh 5. It continues along the curved surface of 231a. Therefore, the large-diameter outer surface coating layer 331a that covers the curved surface of the large-diameter outer surface 231a is held in a planar shape by the stud 41 and the wire mesh 5 (see FIG. 5). Therefore, it is the expanded over occurs crack C is the portion distant from each of the weld point is suppressed, further, peeling, falling can be effectively prevented, thereby the durability improvement of the lance pipe L _1.

Here, the lance pipe L ₁ described above is a well-known method such as welding the above-described stud 41, fixing the cored bar 2 around which the wire mesh 5 is wound in the mold, and pouring a castable refractory into the mold. Manufactured by construction method. When the stud 41 is welded to the cored bar 2, it is only necessary to perform the minimum work of welding the stud only to the large-diameter outer surface 231a on the outer surface 231 of the curved pipe portion 23, so that the production efficiency is improved. .

In addition, although the stud 41 was shown about the form fixed by 3 rows along the axial direction H, if this is fixed to the outer surface 231a by the side of a large curvature radius (r1 in this embodiment), this _1st is demonstrated. The number of columns is not limited within the range of one embodiment. Moreover, although the example in which the locking open arm portion 41a of the stud is opened along the axial direction H has been described, the invention is not limited thereto, and the tangential direction may be used, and the stud opened in the axial direction H and the tangential direction It may be mixed with those that open arms, and this is the same for other embodiments described later.

Next, a description will be given lance pipe L ₂ of the second embodiment. FIG. 6 is a cross-sectional view showing an arrangement relationship in which a net member is wound around a core metal and a stud is fixedly provided for the lance pipe of the second embodiment . In the description of this embodiment, the same parts corresponding to the lance each section of the pipe L ₁ of the first embodiment, are denoted by the same reference numerals. The stud will be described as having a substantially V shape (stud 42).

Compared with the lance pipe L ₁ of the first embodiment, the lance pipe L ₂ of the second embodiment is an embodiment in which the arrangement of the studs 42 with respect to the core metal 2 is the same and the arrangement of winding the wire mesh 5 is different. That is, the wire mesh 5 is wound only on the outer surface of the straight pipe portion 22, not on the outer surface 231 of the bent pipe portion 23 of the cored bar 2.

According to this structure, the peeling of the castable in the lance pipe L ₂ in use, the most inviting likely site dropouts (large-diameter-side surface coating layer 331a castable covering the large-diameter side surface 231a of the core metal 2), the stud Measures are taken by the arrangement of 42. Further, since the welding work of the stud 42 to the cored bar 2 is minimized, the stud 42 can be efficiently manufactured.

And the metal mesh 5 does not necessarily need to be wound around the said outer surface 231 of the core metal 2 like 1st Embodiment. In 2nd Embodiment, the form by which the stud 42 was wound around the outer surface of the straight pipe part 22 which is not welded was shown. The wire mesh 5 has a function of holding the straight pipe covering layer 32 that is likely to be peeled off and dropped off. The winding work of the wire mesh 5 around the core metal 2 at the time of manufacturing the lance pipe is easier than the welding work. Thus, rather than increasing the welding point of the stud easily, thereby peeling the castables, the captive over the entire length of the lance pipe L _2.

L _{1 to} L ₅ : Lance pipe 2: Core metal 22: Straight pipe part 221: Outer surface adjacent to the bent pipe part 23: Curved pipe part 231: Outer surface 231 a: Large diameter outer surface 3: Castable 41 and 42: Stud 41a: Locking arm part 41c: Anchor part

Claims (3)

A molten metal treating agent comprising a straight pipe part and a bent pipe part that is curved and extended from the straight pipe part, and a metal core and a refractory layer covering the outer peripheral surface of the core metal A lance pipe for supplying molten metal to
A plurality of studs fixed to only the outer surface having a large radius of curvature of the curved pipe portion, and a net member wound around the core metal , the plurality of studs and the net member Is embedded in the refractory layer. The lance pipe according to claim 1, wherein the mesh member is wound around an outer surface of the bent pipe portion. The lance pipe according to claim 1, wherein the mesh member is wound around an outer surface portion of the straight pipe portion adjacent to the curved pipe portion.

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