JP4836828B2 - Attaching the lower nozzle to the ladle - Google Patents

Description

  The present invention relates to a method for attaching a lower nozzle to a ladle for attaching a lower nozzle to a lower plate provided in the ladle, for example.

Conventionally, a slide valve for pouring molten steel in the ladle by sliding and opening and closing is provided at the bottom of the ladle that houses the molten steel. This slide valve is mainly composed of an upper plate fixed to the ladle and a lower plate which is provided below the upper plate and slides in the horizontal direction by driving a hydraulic cylinder or the like. The molten steel can be discharged by sliding the lower plate to open the slide valve.
Generally, in order to stably pour molten steel in the ladle, a lower nozzle for pouring molten steel is attached to the lower plate, and if this lower nozzle is used for several charges, it must be replaced when the ladle is maintained. Yes. Thus, the lower nozzle is replaced relatively frequently, and various structures and methods for attaching the lower nozzle to the lower plate are considered (for example, Patent Documents 1 and 2).

In Patent Document 1, a concave dowel portion is provided on the upper end side of the lower nozzle, a sheet-like packing is mounted on the dowel portion, and the packing is interposed between the lower plate and the lower nozzle, whereby the packing is And mounting a lower nozzle to the lower plate. By interposing a packing between the lower plate and the lower nozzle, it is possible to prevent hot water from leaking between the members.
Patent Document 2 discloses that a plate member and a nozzle member are bonded with an adhesive containing a phenol resin. In patent document 2, the said adhesive material is hardened by heating an adhesive material to 200 degreeC, and, thereby, the plate member and the nozzle member are adhere | attached.

Patent Documents 1 and 2 disclose a technique for attaching a lower nozzle to a lower plate by interposing a phenol resin-containing packing between the lower plate and the lower nozzle and heating and curing the packing. ing. As described above, when the lower nozzle is attached, it is important to harden the packing in order to prevent the ingot from being inserted.
Patent Document 3 discloses that a phenol resin is cured by heating at 50 ° C to 350 ° C.
As described above, when the lower nozzle is attached to the lower plate, the packing is heated, and there are the following methods.

The first method is to set the lower nozzle in the ladle at the ladle maintenance area where the ladle is maintained, and then transport it to a different drying area different from the ladle maintenance area in order to dry the ladle. In this drying place, when the ladle is heated by a burner or the like to dry (drying operation), there is one that heats the packing by using the heat in the drying operation by opening the slide valve. .
There is also a second method in which the lower nozzle is set in the ladle at the ladle maintenance site, the filling operation is performed in advance, and the drying operation and the packing curing are simultaneously performed at the drying site.
Utility model registration No. 3025828 Patent No. 3394905 Japanese Patent Laid-Open No. 6-025427

However, although Patent Documents 1 and 2 disclose that the packing is heated, details such as the heating time of the packing are not disclosed. Therefore, regardless of the first method and the second method described above. The fact is that the packing cannot be hardened reliably.
Although Patent Document 3 discloses that the phenol resin is heated at 50 ° C. to 350 ° C., even in this method, the packing is surely cured in the field where the lower nozzle is attached to the lower plate. In fact, the situation has not yet been reached.
Therefore, even if the techniques of Patent Documents 1 to 3 are used, there is still a lot of room for improvement in the method of attaching the lower nozzle to the ladle that can surely prevent the metal from being inserted.

  Therefore, in view of the above problems, the present invention has an object to provide a method for attaching a lower nozzle to a ladle that can surely prevent a bare metal insertion by reliably curing a packing without excess or deficiency. To do.

In order to achieve the above object, the present invention has taken the following measures.
That is, the technical means for solving the problems in the present invention is a method of attaching a lower nozzle to a ladle in which a lower nozzle is attached to a lower plate provided in the ladle. with interposing the phenolic resin-containing packing between the lower plate and the lower nozzle, insert the charcoal or charcoal briquettes to the position of the packing be in the tapping hole, so as to satisfy the following conditions, the charcoal or charcoal By burning the briquette, the packing is heated from the inside to be cured.
1) The surface temperature of the packing after heating is 350 ° C. or higher 2) The heating time is within 10 minutes 3) The total heat value converted to the weight unit of the packing is 40 MJ / kg or more. The method of curing was verified from various angles. As a result, by heating the packing so that the surface temperature of the packing after heating is 350 ° C. or more, the heating time is within 10 minutes, and the value obtained by converting the total heat of heating to the weight unit of the packing is 40 MJ / kg or more. It has been found that the packing is reliably cured.

  According to the present invention, it is possible to reliably prevent the metal from being inserted by reliably hardening the packing without excess or deficiency.

A method for attaching the lower nozzle to the ladle of the present invention will be described. However, the lower nozzle attaching method to the ladle of the present invention is not applied only to the apparatus described below.
As shown in FIG. 1, the slide valve 2 is provided in the lower part of the ladle 1 which accommodates the molten steel extracted from the converter etc. As shown in FIG. In addition, FIG. 1 is the state which opened the slide valve 2 in the state which stood the ladle 1 upright, and sees FIG.
The slide valve 2 includes an upper plate 5, a lower plate 6, a slide member 7, and a housing 4 that accommodates and supports the upper plate 5, the lower plate 6, and the slide member 7.

The housing 4 has an upper frame 4a fixed to the lower portion of the ladle 1 and a lower frame 4b provided below the upper frame 4a and capable of opening and closing the pivot shaft 3. A concave fitting portion 8 is formed on the inner wall side of the upper frame body 4a, and a support portion 4c that supports the slide member 7 when the housing 4 is closed is formed on the lower frame body 4.
The upper plate 5 is fixed so as not to move by being fitted to a fitting portion 8 formed on the upper frame 4 a of the housing 4. The lower plate 6 is disposed on the lower side of the upper plate 5 and attached to the slide member 7, and slides on the lower surface of the upper plate 5 in the horizontal direction. The slide member 7 is provided between the upper frame 4a and the support portion 4c, and slides on the upper surface of the support portion 4c in the horizontal direction.

That is, by expanding and contracting the hydraulic cylinder 9 provided at one end of the slide member 7, the slide member 7 slides in the horizontal direction while sliding on the upper surface of the support portion 4c, and the slide member 7 is lowered as the slide member 7 slides. The plate 6 slides in the horizontal direction while sliding on the upper plate 5.
On the upper side of the upper plate 5, a cylindrical upper nozzle 11 that is attached to the ladle 1 through the housing 4 and the iron skin 10 of the ladle 2 is provided, and on the lower side of the lower plate 6 is a cylindrical shape. A lower nozzle 12 is attached to the slide member 7 via a cylindrical holder 13.

The holder 13 is formed with a horizontally protruding locking portion 14, and the slide member 7 is formed with a cylindrical locked portion 15 that is locked by the locking portion 14 of the holder 13. Yes. A packing 16 is mounted on the upper surface of the lower nozzle 12. The lower nozzle 12 with the packing 16 is inserted into the holder 13, and the upper part of the holder 13 is inserted into the lower part of the slide member 7. Thus, the lower nozzle 12 is detachably attached to the slide member 7 by locking the locking portion 14 of the holder 13 to the locked portion 15 of the slide member 7.
By attaching the lower nozzle 12 to the slide member 7 and opening the slide valve 2, the tap hole 18 provided in the upper plate 5, the lower plate 6, the upper nozzle 11 and the lower nozzle 12 is communicated. The molten steel in the ladle 2 can be poured out from the tap hole 18.

Hereinafter, a method for attaching the lower nozzle to the ladle will be described in detail. In the following description, it is assumed that the upper plate 5, the lower plate 6, and the slide member 7 are arranged in this order from the upper side of the housing 4.
When the lower nozzle 12 is attached to the slide member 7, the phenol resin-containing packing 16 is attached to the upper end surface of the lower nozzle 12, and the lower nozzle 12 is inserted into the holder 13. The packing 16 is interposed between the lower nozzle 12 and the lower plate 16 by locking the locking portion 14 of the holder 13 in which the lower nozzle 12 is inserted to the locked portion 15 of the slide member 7.

As shown in FIG. 2, the ladle 1 is tilted sideways so that the slide valve 2 is fully opened, and in this state, the combustion object 17 is spread over the tap hole 18. At this time, it is preferable to spread the combustion object 17 so that the combustion object 17 comes near the packing 16.
Next, separately from the combustion object 17, a combustible material such as paper is put into the tap hole 18 and ignited to form a seed fire, and the combustion object 17 is combusted. When the combustion object 17 is burned, a pipe 19 is inserted into the hot water outlet 18 from the lower nozzle 12 side, and oxygen is blown through the pipe 19. By doing in this way, heat is transmitted to the packing 16 side by the combustion of the combustion object 17, and the packing 16 is heated.

In the present invention, the combustion object 17 is burned (packing 16 is heated) so as to satisfy the following conditions.
1) The surface temperature of the packing 16 after heating is 350 ° C. or higher. 2) The heating time is within 10 minutes. 3) The value obtained by converting the total amount of heat to the weight unit of the packing 16 is 40 MJ / kg. 17 is a charcoal briquette or charcoal briquette. The surface temperature of the packing 16 is burned with charcoal or charcoal briquette until the surface temperature of the packing 16 becomes 350 or more by a contact thermometer such as a thermocouple. The combustion time of charcoal or charcoal briquette, that is, the heating time is within 10 minutes. The heating time is preferably 5 minutes or more and 10 minutes or less.

The amount of charcoal or charcoal briquette is set so that the total heat of heating converted to the weight unit (MJ / kg) of the packing 16 is 40 MJ / kg or more, and the set amount of charcoal or charcoal briquette is placed in the tap hole 18. Burned with. In calculating the total amount of heat, the unit calorific value of charcoal or charcoal briquette was 30.5 MJ / kg.
By using charcoal or charcoal briquette as the combustible object 17, the surface temperature of the packing 16 after heating can be raised to 350 ° C. or more within 10 minutes, and the total heating value can be easily raised to 40 MJ / kg or more. I was able to. In particular, with charcoal, a high calorific value can be obtained in a short time, and since far infrared rays are contained (radiated) more than those using a gas burner or the like, heat can easily penetrate into the packing 16.

  As described above, by heating the packing 16, the packing 16 is reliably cured, and the contact surface (joint portion) between the packing 16 and the slide member 7 is in surface contact over a wide range, and the packing 16 and the lower nozzle 12 and the contact surface (joint part) with the surface contacted over a wide range. As a result, there is no leakage of hot water from the joint portion, and it is possible to reliably prevent the ingot from being inserted.

  Table 1 shows examples in which the packing 16 was heated by the method of the present invention, and Table 2 shows comparative examples in which the packing 16 was heated without using the method of the present invention.

  In the examples and comparative examples, the ladle 1 has a scale capable of accommodating 250 tons of molten steel. The inner diameter of the tapping hole 18 of the lower nozzle 12 and the lower plate 6 was 85 mm. The components of the lower nozzle 12, the lower plate (in the table, plate) 6 and the packing 16 are as shown in Table 3. In addition, about the component of packing 16 shown in Table 3, the component of a binder is not contained. About the binder, in addition to the packing components shown in Table 3, 20 wt% was added as an outer shell. That is, the addition amount of the binder = weight other than the binder × (20/80). The binder of the packing 16 was a novolac type phenol resin.

As shown in FIG. 3A, in the comparative example, a gas burner 20 for blowing COG (Coke Oven Gas) is provided in the lower nozzle 12, and the packing 16 is heated with this gas burner (COG gas burner) 20.
Further, as shown in FIG. 3B, in the comparative example, an ejector 22 is provided on the lower nozzle 12 via a tubular body 21 fitted in the outlet hole 18, and the ejector 22 faces the outside of the tubular body 21. The packing 16 was heated by drawing air into the tap hole 18 by blowing heat into the refractory or the like in the ladle 1.

In the COG gas burner 20, the unit calorific value of COG is 17.9 MJ / Nm ³ , the COG gas burner 1 shown in Table 2 is 41.8 MJ / h, and the COG gas burner 2 is 167.2 MJ / h. used. As shown in FIG. 3A, in Comparative Examples 6 and 8, the hot water outlet 18 was filled with heat insulating wool (stuffing) 25 and then heated with the COG gas burner 20. In Examples and Comparative Examples, a refractory was attached to the ladle 1 (lining work), and then the inside of the ladle 1 was dried, and then the lower nozzle 12 was attached to the lower plate 6. As shown in FIG. 4, with respect to the curing conditions (curing range) shown in Tables 1 and 2, the percentage of the portion cured with respect to the width W of the packing 16 is shown as a percentage. For example, if an 80% portion (0.8 W) of the packing 16 in the radial width W is cured, the curing range is 80%. Whether or not the packing 16 is cured is determined by the color of the packing 16. In the packing 16, the hardened portion is gray, and the uncured uncured portion is black as before heating. When heat is applied to the packing 16, the packing 16 is cured from the inside toward the outside.

As shown in Table 1, in Examples 1 to 4, the curing range of the packing 16 was 60% or more, and the packing 16 could be reliably cured. It is known from past operation results that if the curing range of the packing 16 is 60% or more, no metal insert (hot water leakage) occurs between the lower plate 6 and the lower nozzle 12.
As shown in Table 2, in Comparative Example 1, the packing 16 is heated by the combustion of charcoal, and the total heat of heating is 36.6 MJ / kg and less than 40 MJ / kg, and the surface temperature of the packing 16 is 330. Since it was less than 350 ° C. at a temperature of C, the heat was insufficient and the packing 16 could not be sufficiently cured (the curing range of Table 2 was 30%).

  In Comparative Example 2, the heating time is 40 MJ / kg or more, the surface temperature of the packing 16 is 350 ° C. or more, and the packing 16 can be sufficiently cured (the curing range of Table 2 is 80%). Is longer than 10 minutes in 12 minutes. As in Comparative Example 2, if the heating time exceeds 10 minutes, it takes too much time to prepare the ladle 1, and the ladle 1 is supplied to a converter or the like in time for the steel out of the molten steel. Can no longer be achieved, leading to a decrease in productivity. Therefore, in Comparative Example 2, the lower nozzle 12 is not efficiently attached to the lower plate 6, which is a problem.

In Comparative Example 3, although the heating time was as short as 3 minutes, since the surface temperature of the packing 16 was 310 ° C. and less than 350 ° C., the heat was insufficient and the packing 16 could not be sufficiently cured (Table 2). The curing range of 10%).
In Comparative Example 4, coke was used as the combustion object 17, but the ignition was very poor and the curing range was 60% or more, which was good, but the heating time was 20 minutes.
In Comparative Examples 5 and 7, since heating was performed by the COG gas burner 20, heat (flame) escaped into the ladle 1, and heat was not easily transmitted to the packing 16 and was not cured. In Comparative Example 6, the heat insulating wool 25 was packed in the ladle 1 so that heat or flame would not escape, but the heating time was 20 minutes. In Comparative Example 8, because the flame emission from the COG gas burner 20 was too strong and the flame bounce from the heat insulating wool 25 was so strong that the COG gas burner 20 failed, the test was stopped in 4 minutes.

In Comparative Example 9, the ejector 22 tried to draw the heat in the ladle 1, but the heat in the ladle 1 was not drawn sufficiently, and the surface temperature of the packing 16 did not rise sufficiently.
The present invention is not limited to the above embodiment.

It is a schematic block diagram of a slide valve. It is explanatory drawing which heats packing with charcoal. (A) It is explanatory drawing which heats packing with a COG gas burner. (B) It is explanatory drawing which heats packing with an ejector. It is a figure which shows the hardening range of packing.

Explanation of symbols

1 Ladle 2 Slide valve 6 Lower plate 12 Lower nozzle 16 Packing

Claims (1)

In the method for attaching the lower nozzle to the ladle, the lower nozzle is attached to the lower plate provided in the ladle.
When the lower nozzle is attached to the lower plate, a phenol resin-containing packing is interposed between the lower plate and the lower nozzle, and a charcoal or charcoal briquette is inserted into the hot water hole at the position of the packing, A method of attaching a lower nozzle to a ladle, wherein the packing is heated and cured from the inside by burning the charcoal or charcoal briquette so as to satisfy the following conditions.
1) The surface temperature of the packing after heating is 350 ° C. or higher 2) The heating time is within 10 minutes 3) The total heat value converted into the weight unit of the packing is 40 MJ / kg or more