JP3373100B2 - Lubrication method and apparatus in twin-drum continuous caster - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to twin-drum type continuous casting for continuously casting thin strip castings, and more particularly to a method and apparatus for supplying a lubricant to a sliding surface between an end surface of a cooling drum and a side dam.

[0002]

2. Description of the Related Art As shown in FIG. 1, a twin-drum type continuous casting machine includes a pair of cooling drums 1 that rotate in opposite directions.
1 are installed so as to be parallel to each other, and a pair of side dams 2 and 2 are pressed against the drum end faces 1a and 1a, and the molten metal pool portion is formed by the upper parts of the drum peripheral surfaces 1b and 1b and the side dams 2 and 2. It is possible to continuously cast a thin strip s having a plate thickness of several mm while cooling and solidifying the molten metal r of molten steel or the like supplied to the molten metal pool 3 on the drum peripheral surfaces 1b and 1b.

As described above, since the drum end surface 1a and the side dam 2 are in sliding contact with each other, the sliding surface is worn. Due to this wear, the service lives of the cooling drum 1 and the side dams 2 are shortened, resulting in high manufacturing costs.

In particular, since the drum peripheral surface 1b comes into contact with the high temperature molten metal during casting, it is thermally expanded and swells like a drum. As a result, as shown in FIG. 3, a wedge-shaped gap 19 is formed between the drum end surface 1 a and the side dam 2, and the outermost edge portion 1 c has a shape protruding toward the side dam 2. As a result, the sliding surface pressure is concentrated on the outermost edge portion 1c, so that the sliding surface around the outermost edge portion 1c is rapidly worn.

When the solidified shell g-1 formed on the drum peripheral surface 1b and the solidified shell g-2 formed on the inner surface of the side weir are connected, the solidified shells g-1 and g-2 are different in speed from each other. Since they attract each other, one or both of the solidified shells peels off and bites into the slab, impairing the slab quality.

In order to prevent this, the solidified shells are separated from each other by vibrating the side dam 2 in the directions of arrows (A) and (B) intersecting the rotation orbit of the cooling drum. However, this vibration causes the side dam 2 to be scraped off by the outermost edge portion 1c of the drum end surface 1a,
Further wear increases.

When the side dam 2 is vibrated in the state where a deep groove is formed on the sliding raceway surface as the wear of the side dam 2 increases, a gap corresponding to the amplitude is formed between the deep groove and the outermost edge portion 1c. Occurs, molten steel is inserted there to form a solidified shell. As a result, the side weir 2 tries to vibrate while being restrained by the outermost edge portion 1c through the solidified shell, so that the sliding surface of the side weir 2 is broken, resulting in poor sealing and molten steel leaking out, making casting impossible. May lead to.

[0008]

In order to prevent abrasion of the sliding surface between the cooling drum and the side dam, a solid lubricant such as a BN block or a graphite block is pressed against the sliding surface at the end surface of the cooling drum. , A method of spraying a liquid lubricant in which BN powder is dispersed is known, for example, from JP-A-63-248547. However, with the method of pressing the solid lubricant, the lubricant adhering to the end surface of the cooling drum is scraped off when it makes sliding contact with the side weir, and is shaken off by the vibration of the side weir, so a sufficient lubrication effect is obtained. I can't.

The method of spraying the liquid lubricant is apt to cause nozzle clogging. Further, since the liquid lubricant is vaporized between the drum end surface and the side weir, a gas bubbling phenomenon occurs in the molten metal pool 3 or the thickness of the solidified shell generated on the inner surface of the side weir due to heat removal due to vaporization is increased. The quality of one piece is impaired. Furthermore, since the liquid lubricant remains in the pipe and nozzle after use, its removal is troublesome.

Therefore, the present invention is a twin-drum type continuous casting for continuously casting thin strip slabs, wherein the sliding surface between the cooling drum end surface and the side weir does not cause the above-mentioned problem and a sufficient amount of lubricant is used. The challenge is to efficiently supply.

[0011]

The lubrication method in a twin-drum type continuous casting machine of the present invention for solving the above-mentioned problems is a pair of cooling drums rotating in mutually opposite directions, and sliding contact with both end faces of the cooling drums. In a lubrication method in a twin-drum type continuous casting machine that continuously casts a thin strip casting while supplying molten metal to a molten metal pool formed by a pair of side weirs, sliding of the pair of cooling drums and side weirs The powder lubricant is supplied to the surface and melted, and the load received by the side dam due to the sliding contact between the cooling drum and the side dam is detected, and the supply amount of the powder lubricant is controlled according to the load. It is characterized by doing.

The twin-drum type continuous casting machine of the present invention is also
Kicking lubricating device, the lubricating instrumentation that definitive in twin drum type continuous casting machine
Sliding surface of Oite the location, the powder cutout pneumatically device, a feed pipe feel linked to the powder cut pneumatically device, and is connected to the gas feed pipe and said pair of cooling drums and side weirs and powder nozzles directed to a load cell provided in the support shaft of the side weirs, controller is arranged to control the powder cut valve of the powder cut air transfer device in accordance with the signal of the load cell < br /> is characterized.

[0013]

2 shows a side sectional view of a twin-drum type continuous casting machine for carrying out the present invention, and FIG. 3 shows a partial plan view taken along line XX of FIG. , The same reference numerals as those in FIG. 1 have the same names and actions, and therefore their explanations are omitted.

The drum end faces 1a, 1a are coated with, for example, tungsten carbide, and the sliding surface of the side dam 2 with the drum end faces 1a, 1a is covered with a refractory plate such as fine ceramics. , Refractories are also applied to other parts.

The powder severing / pneumatic feeding devices 5 and 5 mainly include a tank 6 for containing the powder lubricant f, a powder slicing valve 7 and a powder scavenging device 8. The tank 6 is provided with shelves 9 as necessary to prevent the powder lubricant f contained in the tanks from hanging. At the lower end of the tank 6, a powder cut-out valve 7 for intermittently opening and closing to quantitatively cut out the powder lubricant f is provided, and the powder in the tank 6 is opened and closed depending on the opening / closing timing of the powder cut-out valve 7. The required amount of lubricant f can be cut out.

A powder feeding device 8 is connected to the lower end of the powder cut-off valve 7, and the air feeding pipe 12 is connected to the powder feeding device 8.
Are connected. The powder air feeding device 8 is provided with a conical powder dispersion member 10 as needed, and the powder dispersion member 10 can disperse and discharge the powder lubricant f so as to facilitate air transportation. it can. Further, a compressed air ejection pipe 11 is connected to the powder air feeding device 8, and the powder lubricant f dispersed and discharged from the powder dispersion member 10 is vaporized by the compressed air ejected from the compressed air ejection pipe 11. It is pneumatically fed to the feed pipe 12.

An injector nozzle 13 is connected in the middle of the pneumatic pipe 12 if necessary, so that the powder lubricant f in the midst of pneumatic transportation can be additionally fed. A powder nozzle 14 is connected to the tip of the pneumatic pipe 12, and the powder nozzle 14 is directed to a gap portion 19 between the drum end surface 1a and the side dam 2 shown in FIG.

The side weir 2 is supported by a support shaft 16 and is pressed against the drum end surface 1a by a pressing device (not shown), and the side weir 2 is frictionally resisted by sliding contact with the drum end surface 1a rotating in the direction of the arrow. Receive a load. The greater the load, the greater the frictional resistance, and the sliding surface 18 between the drum end surface 1a and the side dam 2 is worn.

Reference numeral 15 denotes a load cell for detecting the load, which is provided on both left and right sides and a lower side of the support shaft 16 of the side dam, and detects the load received by the side dam 2 by the sliding contact. be able to. Load cell 1
The load signal detected by 5 is taken into the control device 17, and the control device 17 controls the powder cutout valve 7 of the powder cutout air feeding device 5 according to the load.

Although the load cells 15 are provided at three positions on the right and left sides of the support shaft 16 and at the lower side, the number of the load cells 15 may be appropriately increased or decreased. Further, the powder cutting and air feeding device 5 is provided for each end surface of each cooling drum, but it is possible to increase or decrease the number of bases suitable for the conditions of both cooling drums. Further, the powder nozzle 14 may be branched from the pneumatic pipe 12 and a plurality of powder nozzles 14 may be provided for each end surface of the cooling drum.

Next, the operation of the apparatus shown in FIGS. 2 and 3 will be described. The hot water supplied to the hot water pool portion is cooled and solidified on the drum peripheral surfaces 1b, 1b which rotate in the direction of the arrow to produce a solidified shell g, and the solidified shell is the cooling drum 1,
1 is pressed at the closest point 4 to form a strip slab s.

In the tank 6 of the powder cut-out pneumatic feeder 5, a powder lubricant f such as powdery glass or nitrates (for example, sodium nitrate) is contained, and the powder lubricant f is at a working temperature. Viscosity at 300-800 ° C is 600-100
0 poise, particle size is about 100 to 200 mesh.
The powder lubricant f contained in the tank 6 is supported by the shelf 9 to prevent the phenomenon of hanging from the shelf, and drops from the powder cut-out valve 7 that opens and closes intermittently to the conical powder dispersion member 10 to form a circle. It is dispersed in the circumferential direction and falls.

The powder lubricant f dispersed and dropped is supplied to the pneumatic pipe 12 by compressed air blown from the compressed air jet pipe 11.
Then, the powder is delivered to the powder nozzle 14 by an injector nozzle 13 provided in the middle of the air delivery pipe 12. The powder lubricant f sent to the powder nozzle 14 is sprayed on the gap 19 between the drum end surface 1a and the side dam 2 shown in FIG.

Since the temperature of the sliding surface 18 is about 800 ° C., the powder lubricant f adhering to the sliding surface 18 quickly melts and the gap 1
9 to fill the sliding surface 18 and provide sufficient lubrication. When the side weir 2 is further vibrated, the side weir 2
In the process of oscillating in the direction of arrow B, the side dam 2 functions to draw the melted lubricant to the drum outermost edge 1c side, and an internal pressure is generated in the melted lubricant by the wedge effect. Therefore, the molten lubricant is spread between the drum end surface 1a and the side dam 2 and serves as a medium for fluid friction to be used for fluid lubrication of the sliding surface 18.

On the other hand, the side dam 2 receives a load corresponding to the frictional resistance due to the sliding contact with the drum end surface 1a rotating in the direction of the arrow. This load is detected by the three load cells 15 and taken into the controller 17. The control device 17
The powder cut-out valve 7 of the powder cut-out air feeding device 5 is controlled by the control signal according to the load. As a result, the sliding surface 18 shown in FIG. 3 is supplied with the powder lubricant f in an amount corresponding to the frictional resistance, so that the sliding surface 18 is kept in an appropriate lubrication state.
It is possible to obtain the sealing action of and prevent wear.

[0026]

EXAMPLE A twin-drum type continuous casting machine shown in FIG. 2 was used for continuous casting of SUS304 stainless steel cast pieces having a plate thickness of 2 to 6 mm and a plate width of 800 mm. During the casting, 20 to 30 g of powdered glass having an average particle size of 150 mesh as a powder lubricant was supplied per 1 ton of molten molten steel. As a result, no melt leakage occurred during casting, and the shape of the end of the cast piece was good. Further, the life of the cooling drum and the side weir was extended about 10 times as compared with the case where the powder lubricant was not supplied.

[0027]

INDUSTRIAL APPLICABILITY According to the present invention, in the casting of thin strip cast by a twin-drum type continuous casting machine, powder lubricant is sprayed on the sliding surface between the cooling drum and the side dam by a powder nozzle, and the sprayed powder is sprayed. Since the body lubricant is melted by the heat of the sliding surface and supplied to the sliding surface, the amount required to seal the sliding surface is greater than the conventional solid lubricant pressing method. The lubricant can be supplied, and the nozzle clogging is extremely small as compared with the method of supplying the liquid lubricant.

As a result, by reliably sealing and protecting the sliding surface, it is possible to prevent the defective shape of the end of the cast slab due to the leakage of the molten metal on the sliding surface, and to prevent the sliding surface from being worn and to cool the cooling drum and the cooling drum. The life of the side weir can be extended. Furthermore, since the lubricant is less likely to remain in the pipes and nozzles, maintenance such as cleaning is easy.

[Brief description of drawings]

FIG. 1 is a perspective view of a twin-drum type continuous casting machine.

FIG. 2 is a side view of a twin-drum type continuous casting machine for carrying out the present invention.

FIG. 3 is a plan view taken along line XX of FIG. 2 showing a gap between a cooling drum and a side dam.

[Explanation of symbols]

1 ... Cooling drum 1a ... Drum end surface 1b ... Drum surface 1c ... most edge of drum 2 ... Side weir 3 ... Hot water pool 4 ... Drum closest point 5 ... Powder cut-out pneumatic device 6 ... tank 7 ... Powder cutoff valve 8 ... Powder pneumatic device 9 ... Shelf 10 ... Powder dispersion member 11 ... Compressed air jet pipe 12 ... Pneumatic piping 13 ... Injector nozzle 14 ... Powder nozzle 15 ... Load cell (load detector) 16 ... Support shaft for side dam 17 ... Control device 18 ... Sliding surface 19 ... Wedge-shaped gap s ... Thin strip slab r ... molten metal f ... Powder lubricant

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-2-241646 (JP, A) JP-A-2-299749 (JP, A) JP-A-4-46656 (JP, A) JP-A-1- 317660 (JP, A) JP 6-15418 (JP, A) JP 4-81250 (JP, A) JP 63-248547 (JP, A) JP 8-52539 (JP, A) JP-A-6-15416 (JP, A) JP-A-60-21158 (JP, A) JP-A-4-322850 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B22D 11/06 330

Claims (2)

(57) [Claims] 1. A strip slab while supplying molten metal to a molten metal pool formed by a pair of cooling drums rotating in opposite directions and a pair of side dams slidingly contacting both end faces of the cooling drum. In a twin-drum type continuous casting machine for continuously casting
In the lubrication method, while supplying and melting the powder lubricant to the sliding surface between the pair of cooling drums and the side dam,
Lubrication in a twin-drum type continuous casting machine, characterized in that a load received by the side dam is detected by sliding contact between the cooling drum and the side dam, and a supply amount of the powder lubricant is controlled according to the load. Method. Wherein the pair of cooling drums rotating in opposite directions, Jun in twin drum type continuous caster and a pair of side weirs which slides in contact with both end faces of the cooling drum
In the sliding device , a powder cutting air feeding device, an air feeding pipe connected to the powder cutting air feeding device, and a sliding surface of the pair of cooling drums and side dams connected to the air feeding pipe. A powder nozzle oriented, a load cell provided on the support shaft of the side dam, and a control device for controlling the powder cut-out valve of the powder cut-out air feeding device according to the signal of the load cell. Lubricating device in twin-drum type continuous casting machine.