JPH0740016A - Method for manufacturing sulfur-filled wire - Google Patents

Abstract

(57) [Summary] [Purpose] To manufacture so-called injection wire for adding sulfur as an alloying component to molten steel. [Structure] A wound metal tube is maintained at a temperature of 120 to 150 ° C., sulfur liquefied in the temperature range is injected from one end of the metal tube to be filled, and then cooled. [Effect] Unlike the method of manufacturing by winding a metal plate, since there is no seam, it does not absorb moisture, has no bending tendency, and is suitable for applications that require precision in the target position such as continuous casting. Further, it can be manufactured with higher efficiency than the method of filling powder.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the production of a metal pipe such as a steel pipe filled with sulfur, and its application is a so-called injection wire for adding sulfur as an alloying component to molten steel. .

[0002]

2. Description of the Related Art As a method of adding a metal additive to steel or the like in a ladle, a so-called injection wire in which an additive powder is contained in a metal coating is used. This is an effective method for things such as those that may oxidize on the surface of the metal bath, react with slag floating on the surface, and may float before melting in the bath due to its extremely small specific gravity. Has become. For example, addition of Ca to steel achieves a large improvement in yield as compared with the method of adding a lump by this method.

By the way, sulfur is also added to steel by the above-mentioned injection wire. Sulfur is added for the purpose of producing free-cutting steel because it has the effect of improving the machinability of steel. When manufacturing steel, most of the alloying elements are added to the ladle in principle, but they may be added during continuous casting for the purpose of fine adjustment of the composition. Particularly in the case of sulfur, it is disclosed in Japanese Patent Application Laid-Open No. 62-142053 that addition is made with an injection wire during continuous casting in order to change the sulfur concentration between the surface portion and the central portion of the material. That is, in the case of producing nuts in free-cutting sulfur steel, the surface is subjected to severe cold working, which causes cracks and causes defects when welding, so lowers the sulfur, and the center is sulfur for thread cutting. It is intended to manufacture materials with high This kind of thing was traditionally an ingot agglomeration of rimmed steel, and was made by the so-called core kill method, in which components are added to the core part when the shell part solidifies, but to reduce cost, it is going to be manufactured by continuous casting. To do.

FIG. 3 is a diagram showing a method of using an injection wire in such continuous casting. Molten metal 2 is injected from a dipping nozzle 5 into a continuous casting mold 4. The metal additive is added thereto by the injection wire 1. If the inserted injection wire 1 enters the molten metal 2 and is immediately melted, the additive component will enter the cross-section of the cast piece almost uniformly.
As shown in (4), when the material melts in the deep portion, the solidified shell 3 has already been formed, so it is added only to the core portion. FIG. 4 is a view showing a cross section of such a cast piece. In this case, there is no sulfur component from the injection wire 1 of the shell portion 6 and only the core portion 7 is added.

[0005]

However, when the injection wire is used for continuous casting, there is a case where the required performance cannot be exhibited by using the conventional one for adding the alloy material in the ladle. I knew that there was. That is, when using it for molten metal in a pot, there is no particular problem even if the wire is inserted while meandering because it has a habit, but in the case of continuous casting, billets with a side of one hundred and several tens mm are used. In some cases, if the wire is meandering and sent out, the wire may not be sent to a predetermined location of the mold, which may cause defective casting. However, the conventional injection wire uses a strip-shaped metal plate as a U
Bending rigidity was not the same depending on the bending direction because the additive powder was added while bending into a mold, and it was molded into a round shape with joints, so it was easy to bend.

Further, when the injection wire is inserted for the purpose of changing the component only in the central portion, it is necessary to melt the wire when the shell portion is solidified to an appropriate position. That is, the thickness of the jacket is required so that it does not melt to a certain depth. However, in the conventional way of thinking, the outer sheath of the injection wire is more than a packaging, so that the thickness of the outer sheath has not been changed. Also, when manufacturing by bending a strip-shaped metal plate,
Due to the capability of the device, it was not possible to manufacture a metal plate having a large thickness.

[0007]

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned problems, and in a method for producing a wire in which a metal tube is filled with sulfur, the rolled metal tube is
A method for producing a sulfur-filled wire, which is characterized in that the liquefied sulfur is maintained at a temperature of 0 to 150 ° C., liquefied sulfur is injected from one end of the metal tube to be filled, and then cooled.

[0008]

In the present invention, liquefied sulfur is injected into the metal tube from one end to fill it. That is, in the conventional method for manufacturing an injection wire, sulfur is handled in a powder state, but in the present invention, the characteristic that sulfur becomes a low-viscosity liquid within a specific temperature range is utilized.

Further, in the conventional method in which a strip-shaped metal plate is used as a starting material and is formed into a round shape to form an outer cover, there are overlapping portions and folding portions, which tend to cause bending blunting, but should be a seamless metal tube. This can be prevented because the cross section has good symmetry. Further, in the case where the metal plate of the outer cover is formed into a round shape and the filler is added, the wall thickness t is limited, and the ratio t / D to the outer diameter D of the wire cannot be increased due to processing restrictions. Although it was less than 1, the wall thickness can be increased by the method of filling the metal tube. The term "seamless metal tube" as used in the present invention means that the additive-containing wire as a product has no joint such as superposition or folding. Therefore, even if the steel pipe used as a raw material in the production method of the present invention is not a seamless steel pipe produced by billet perforation but a welded steel pipe produced by welding band steel, it does not matter.

By the way, as a technique for charging a filler into a metal tube, there is one disclosed in Japanese Patent Laid-Open No. 59-35898. This is a method in which a rolled metal tube is placed on a vibrating table, and the powder as the content is supplied from one end of the vibrating table to fill the powder. This method is industrially proven and has few technical problems, but it takes time to feed the powder into the metal tube by vibration. On the other hand, in the method of the present invention, since the liquid is injected into the metal tube, it can be filled in a short time.

FIG. 2 shows the relationship between sulfur viscosity and temperature.
The melting point of sulfur is 114 ° C. Although the viscosity decreases as the temperature rises from the melting point, the viscosity rises sharply from about 160 ° C. to rubbery sulfur. Therefore, 120 to 15
It is expedient to inject liquid sulfur into the metal tube in the temperature range of 0 ° C. In filling the liquid sulfur in the metal tube, either a method of injecting while applying pressure or a method of performing vacuum suction from the end of the metal tube on the opposite side to the injection may be used. Further, it is necessary to keep the entire metal tube in the above temperature range where sulfur becomes a liquid with low viscosity so that sulfur does not solidify in the middle.

The metal tube thus injected with liquid sulfur can be used as a product as it is if it is cooled. In the method of filling the powder described above, in order to increase the packing density of the contents and prevent the powder from falling out of the cross section, it is necessary to reduce the diameter of the metal tube after drawing by a method such as drawing, but in the method of the present invention, Is not necessary because it is closely packed. Further, since the filling does not take time, it is possible to perform the filling with high efficiency even if the target final product has a small diameter. However, it is of course also possible to reduce the diameter after filling with sulfur as described above to obtain the required diameter.

[0013]

1 is an example of an apparatus for carrying out the method of the present invention. The constant temperature bath 11 has a closed atmosphere and is heated to a constant temperature, for example, 13 by a heating device (not shown).
It is heated to 5 ° C. A coiled metal tube 13 is inserted into the constant temperature bath 11, one end of which is connected to an injection funnel 14 and the other end of which is connected to a relay container 15. The relay container has a structure in which it is hermetically closed by a lid, and is further connected to the vacuum suction pump 16. Further, a float switch 17 is provided in the relay container, and when molten sulfur starts to accumulate at the bottom, the float inside the flow switch floats up and the electric circuit is closed to detect it.

In this apparatus, the sulfur 12 previously heated and melted at 135 ° C. is injected into the injection funnel, and the vacuum suction pump 16 is operated to perform suction. When sulfur is sucked from one end into the wound metal pipe 13 and is discharged from the other end and sulfur is accumulated in the relay container 15, the float switch 17 operates to open and close a vacuum suction pump switch (not shown). ) Is opened and stopped, and the metal tube 3
The side that was sucking in is opened to atmospheric pressure. After that, if the wound metal tube 3 is taken out from the constant temperature bath 1 and cooled, the manufacturing process is completed. The manufacturing method of the present invention is not limited to the above embodiment, and for example, the metal tube heating method may use a tank of oil or molten salt.

[0015]

According to the present invention, it is possible to easily manufacture a sulfur-filled wire which is an additive for steelmaking in continuous casting or the like and has a seamless outer skin. As described above, in the case of a wire having a seamless outer shell, the outer cover does not open and the additive leaks during the feeding by the wire injector, the additive does not absorb moisture during the storage of the wire, and oxidative deterioration does not occur. Also, because there are no processing restrictions when making thick ones,
It is possible to make a material that melts down at a given depth when fed into molten metal.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an apparatus for carrying out a manufacturing method of the present invention.

FIG. 2 is a graph showing the relationship between temperature and viscosity of liquid sulfur.

FIG. 3 is a diagram showing a method of using an injection wire in continuous casting.

FIG. 4 is a cross-sectional view of a continuously cast slab containing an additive in the core.

[Explanation of symbols]

 11 Constant Temperature Bath 12 Sulfur 13 Metal Tube 14 Injection Funnel 15 Relay Container 16 Vacuum Suction Pump 17 Float Switch

Claims (1)

[Claims] 1. A method for producing a wire in which a metal tube is filled with sulfur, wherein the wound metal tube has a thickness of 120-120.
A method for producing a sulfur-filled wire, which is characterized by holding at a temperature of 150 ° C., injecting sulfur liquefied in the temperature range from one end of the metal tube to fill it, and then cooling.