JPH09108789A - Method for applying coating agent on belt for belt type continuous casting machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a belt coating method by which a solidified shell is uniformly grown and a cast slab having good surface characteristic can be obtd., in the case of continuously casting the thin cast slab by a belt type continuous caster. SOLUTION: At the time of applying a slurrified coating agent 5 having high solid part ratio and large average grain diameter on the belt 7 for the belt type continuous caster, the directions of velocity vectors at the contact point of an applicator roll 1 with the belt 7 for the belt type continuous caster are made reverse, and the directions of velocity vectors at the contact point of a pickup roll 3 with the applicator roll 1 are made reverse. Further, the pushing force of the applicator roll 1 to the belt 7 is controlled to >=1.2kg/mm, and the pushing force between the pickup roll 2 and the applicator roll 1 is controlled to >=0.5kg/mm, and the gap between the pickup roll 2 and a meter roll 3 is controlled to 100-150μm, and the peripheral velocity of the meter roll 3 is controlled to 3-10mpm, and the peripheral velocity of the pickup roll 2 is controlled to 7-30mpm to obtain the cast slab having good surface characteristic.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a coating agent for a belt for a continuous belt casting machine used for forming a mold in a single belt type or twin belt type continuous casting machine for producing thin cast pieces. The present invention relates to a coating method.

[0002]

2. Description of the Related Art Recently, a twin-belt continuous casting method or a single-belt continuous casting method for directly manufacturing a thin cast piece having a thickness of several mm to several tens of mm close to the final shape from molten metal such as molten steel Casting methods are drawing attention.

In each of these belt-type continuous casting methods, an endlessly rotating belt is used as a mold. For example, in the twin-belt type continuous casting method, it is disclosed in JP-A-59-5686. A continuous casting machine having a structure as described above is used. The basic structure is shown in FIG. That is, the pulleys 1 are arranged so as to face each other.
A mold (hot water) formed by a pair of metal belts 11 wound around 4, 15, 16 and rotating endlessly and dam blocks (not shown) arranged at both end portions of the pair of metal belts. Molten metal 18 is injected from the tundish 12 through the nozzle 13 into the pool 20),
Is cooled by a circulating coolant in a cooling box 21 arranged on the back surface thereof, and is supported by a support roll 17 while cooling and solidifying the molten metal in the mold, and is drawn out to produce a thin cast piece 19. It is a thing.

Starting with this twin belt type continuous casting machine,
In a continuous casting method of a thin cast piece using a belt type continuous casting machine in which a mold is formed by a belt that rotates endlessly, it is important to stably maintain the surface quality of the thin cast piece at a high level. For that purpose, it is necessary to uniformly generate a solidified shell, and slow melting of molten metal at the time of solidification and improvement of lubricity between a slab and a mold have been proposed. It has been proposed to coat the surface (belt surface). Conventionally, as one of the coating methods, JP-A-60-24248 and JP-A-HEI-1
A roll coater method as disclosed in Japanese Laid-Open Patent Application No. 162546 is used. These are proposed as a method for uniformly applying grease or castor oil, and also as a method for improving the uniformity of the coating thickness by applying a roll coater method or a porous leveling roll to level the coated film. There is.

[0005]

However, in the method disclosed in Japanese Patent Laid-Open No. 60-24248, when a slurry having a large solid content particle size is coated, the solid content of the coating agent is clogged between the coating roll and the auxiliary roll. There's a problem.
Further, in the method disclosed in JP-A-1-162546, there is a problem in that the solid content in the slurry is scraped off by the leveling roll, so that the coating thickness is not uniform. Further, unless the peripheral speed of the meter roll is higher than a certain speed, there is a problem that the coating thickness varies greatly and defects occur in the cast slab. Due to the uneven coating thickness, uneven cooling of the solidified shell and local poor lubrication are unavoidable, which is sufficient from the viewpoint of cross-cooling of the solidified shell and stable lubrication between the solidified shell and the mold. Is hard to say.

Therefore, an object of the present invention is, when a thin cast piece is continuously cast by a belt type continuous casting machine, has an excellent slow cooling function on a surface of a belt forming a mold, which is in contact with molten steel, and has a slab (solidification). (Shell) with excellent lubricity and evenly coating a slurry-like coating agent containing a large amount of solids with a large particle size to evenly remove heat from the molten steel and grow the solidified shell uniformly. Thus, the present invention provides a method for coating a belt for a belt-type continuous casting machine with a coating agent, which enables obtaining a slab having good surface properties.

[0007]

The gist of the present invention is to provide (1)
A coating agent tank containing a coating agent, a pickup roll semi-submerged in the coating agent in the tank, an applicator roll supported in contact with both the pickup roll and a casting belt, and the pickup A coating agent for a belt for a continuous casting machine using a coating device including a meter roll supported in parallel with the roll and maintaining a predetermined gap, and a scraper supported in parallel with and in contact with the meter roll. In the coating method, the inorganic coating agent has a solid content ratio of 40 to 60% and an average particle diameter of 30.
Slurry of ˜50 μm, and the velocity vector of the applicator roll and the belt at the contact point of the belt type continuous casting machine, the velocity vector of the both at the contact point of the pickup roll and the applicator roll, and the closest value of the pickup roll and the meter roll. Coating of a coating agent on a belt for a belt-type continuous casting machine, characterized in that the velocity vectors of the two points at the respective points are opposite to each other, and wave contact is performed with a coating thickness of 60 μm to 150 μm and a thickness accuracy of ± 30 μm. Method (2) Pressing force of applicator roll to belt is 1.2kg / mm or more, pressing force of pickup roll and applicator roll is 0.5kg / mm or more, gap between pickup roll and meter roll is 100 ~ 200μm, meter Roll speed is 3 ~ 10mpm, picker The roll speed of the roll is 7 ~
A coating method for coating a belt for a belt type continuous casting machine according to the above (1), characterized in that the coating amount is 30 mpm.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an apparatus for coating a belt for a belt type continuous casting machine with a coating agent. This apparatus uses a slurry coating agent 5 and a coating pan 6
The pick-up roll 2 scoops it up, the meter roll 3 adjusts the primary thickness, and then it is transferred onto the applicator roll 1 and further transferred from the applicator roll 1 onto the belt 7. Further, a scraper 4 is pressed against the meter roll 3 in order to prevent the coating agent 5 scraped off for adjusting the coating thickness from reattaching to the pickup roll 2.

The coating thickness of the coating must be 60 μm or more in order to realize slow cooling of the slab and prevent the occurrence of cracking defects due to uneven shell formation. When the coating agent is dried due to the coating being too thick. In order to prevent the occurrence of defects in the coating film due to bumping of the solvent, it is necessary that the thickness be 150 μm or less.

The thickness accuracy of the coating is determined in order to prevent non-uniformity of shell formation and the occurrence of crack defects in the slab.
It is necessary to secure ± 30 μm.

The solid content ratio of the applied coating agent is
In order to prevent solids from settling and to secure the coating thickness, 4
It must be kept at 0% or more. Further, in order to prevent unevenness in the width direction of the coating agent lifted by the pickup roll and to ensure thickness accuracy, the solid content ratio should be 60%.
Must be kept below%.

The average particle diameter of the solid content of the coating agent is 30 in order to prevent sedimentation of the solid content particles, to secure the stability of the slurry, and to maintain the uniformity of the coating thickness.
It is necessary to secure the range of ˜50 μm.

Further, the form of the coating agent needs to be a slurry for stable application.

The rotation direction of the applicator roll is related to the belt for the belt type continuous casting machine, and the clogging between the roll of the solid content of the coating agent and the space between the belts is suppressed so that the conveyance amount is uneven in the width direction on the belt. It is necessary to reverse the directions of the velocity vectors of the applicator roll and the belt at the contact point of the belt in order to enable the transport of the coating agent without a gap.

The rotating direction of the applicator roll is related to the pick-up roll, so that the solid content of the coating agent can also be conveyed onto the applicator roll. It is necessary to reverse the direction of.

In order to secure the required coating thickness and thickness accuracy without encouraging the variation in coating agent thickness at the time of picking up, the rotation direction of the meter roll is at the closest point between the pickup roll and the meter roll. It is necessary to reverse the direction of the velocity vector of.

The pressing force of the applicator roll against the belt suppresses the coating agent from slipping through without being transferred between the roll and the belt, and enables the coating agent to be conveyed evenly in the roll width direction. 1.2 kg
Must be at least / mm. The pressing force between the applicator roll and the pick-up roll is 0.5 kg / mm in order to prevent the coating agent from slipping through without being transferred between the rolls, and to make it possible to convey the coating agent evenly in the roll width direction. It is necessary to be above.

The gap between the meter roll and the pick-up roll is to prevent the solid content of the coating agent from clogging between the rolls, to avoid the occurrence of local uncoated portions, and to secure the coating thickness accuracy. It should be 100 μm or more. Further, in order to suppress the ripple of the coating agent due to the large amount of lift of the coating agent and ensure the accuracy of the coating agent thickness, the gap between the meter roll and the pickup roll is 200 μm.
It must be:

The peripheral speed of the meter roll needs to be 3 mpm or more in order to uniformly exert the leveling effect of the meter roll in the roll width direction and suppress the coating thickness variation. Further, in order to suppress the amount of coating agent removed and to secure the coating thickness transferred to the applicator roll, the peripheral speed of the meter roll needs to be 10 mpm or less.

The peripheral speed of the pick-up roll must be set to 7 mpm or more in order to avoid pick-up defects and ensure the coating thickness. Moreover, in order to suppress the fluctuation of the lift of the coating agent and ensure the uniformity of the coating film, the pick-up roll peripheral speed is 30 mp.
Must be set to m or less.

[0021]

Embodiments of the present invention will be specifically described below with reference to the drawings. First, as a preliminary test for forming a uniform film, a urethane rubber roll is used as the applicator roll 1 in the test apparatus of FIG. 1, and the pickup roll 2 and the meter roll 3 are made of steel and hard chrome plated on the surface. The scraper 4 is made of urethane rubber and the coating agent is composed of the main component Ca0,
Using SiO ₂ , viscosity 3 poise, moisture content 50%, and solid content average particle diameter of 35 μm, the following five items were investigated.

First, Table 1 shows the test conditions for investigating the relationship between the roll rotation direction and the coating characteristics. Pickup roll peripheral speed 7 mpm, applicator roll peripheral speed 7 mpm, meter roll peripheral speed 3 mpm, belt speed 5 mpm, applicator roll pressing force to belt 1.5 kg / mm, pickup roll pressing force to applicator roll 0.7 kg / mm The test was conducted at. As a result, by setting the rotation directions of the pickup roll 2, the applicator roll 1, and the meter roll 3 to be R2, R4, and R6 in FIG. 1, the solid content of the coating agent does not clog between the rolls, that is, uncoated. It can be applied without causing parts.

Secondly, Table 2 shows the test conditions at the time of testing the pressing force of the applicator roll 1 against the belt mold and the pressing force of the pickup roll 2 against the applicator roll 1. The rotation direction of each roll was the same as that of test No. 6 in Table 1. As a result, the pressing force of the applicator roll 1 against the belt is set to 1.2 kg / mm or more as the pressing force per roll unit length, so that the coating agent 5 does not cause film breakage due to defective delivery between rolls. Can be applied. Further, similarly, by setting the pressing force between the pickup roll 2 and the meter roll 3 to be 0.5 kg / mm or more, coating can be performed without causing film breakage due to defective transfer between coating rolls. Due to roll rigidity, the maximum pressing force is 2.0 kg between applicator roll 1 and belt 7.
/ mm or less, and the range between the pickup roll 2 and the applicator roll 1 is preferably 3.5 kg / mm or less.

Thirdly, the influence of the gap between the pick-up roll 2 and the meter roll 3 on the coating characteristics was examined by the test Nol 2 in Table 3. As a result, the gap between the pickup roll 2 and the meter roll 3 is 100μ.
When it is at least m, it can be applied without clogging.

Fourthly, regarding the influence of the peripheral speed of the pickup roll 2 on the coating characteristics, the test Nos. 5 and 6 in Table 3,
7 and 8 were investigated. As a result, by setting the peripheral speed of the pick-up roll 2 to 7 mpm or more, it is possible to apply the coating agent 5 without picking up uneven stripes due to the pickup amount variation. Also, by setting the peripheral speed of the pickup roll 2 to 30 mpm or less, excessive pickup amount is suppressed, and the meter roll 3
The variation can be leveled with. Therefore, uniform coating is possible by setting the peripheral speed of the pickup roll 2 in the range of 7 mpm to 30 mpm.

Fifth, the peripheral speed of the meter roll 3 was investigated by Test Nos. 3, 9, 10 and 11 in Table 3. As a result, by setting the peripheral speed of the meter roll 3 to 3 mpm or more, the ability to scrape off the picked-up coating agent 5 is exerted, and the coating agent layer has a large thickness and does not cause poor drying after application. The patter pattern can be suppressed. Further, by setting the coating thickness of the coating agent 5 to 150 μm or less, the occurrence of poor drying can be prevented. Further, by setting the peripheral speed of the meter roll 3 at 10 mpm or lower, it is possible to secure the minimum coating thickness necessary to prevent defects in the cast slab.

The coating apparatus of FIG. 1 was incorporated into the twin-belt type continuous casting machine of FIG. 4 so as to have the configuration of FIG. 5, and a casting test was conducted while coating the belt 7 with the coating agent. Medium carbon steel, which is said to have high cracking susceptibility, was used as the casting material, and the casting results were evaluated by the length of cracking defects per unit length of the casting. The influence of coating thickness and coating thickness variation is
The test Nos. 1 to 8 in Table 4 were investigated, and the results are shown in Table 4,
This is shown in FIGS. By coating by the method of the present invention, coating with excellent coating thickness uniformity is performed, and cooling in the mold of the solidified shell is made uniform and the solidified shell
Lubrication between the molds can be made smooth over the entire surface, and a slab with excellent surface properties can be obtained.

Although the twin-belt type continuous casting machine has been described as an example, the present invention is not limited to this.
Similarly, it can be applied to a single belt type continuous casting machine that produces and grows a solidified shell on the belt surface.

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

[Table 3]

[0032]

[Table 4]

[0033]

INDUSTRIAL APPLICABILITY According to the present invention, in a belt for continuous casting of thin-walled slabs, the surface of the belt in contact with the molten metal is uniformly coated with an inorganic coating agent, so that the slabs are cooled evenly to form solidified shell It promotes uniform growth, and since the coating has high lubricity, it causes a slip phenomenon between the solidification shell and the mold, eliminating the constraint of solidification shrinkage. As a result, the thin cast piece produced has good surface properties. As described above, according to the present invention, it is possible to manufacture a thin-walled slab with excellent quality and to perform stable production.

[Brief description of the drawings]

FIG. 1 is a schematic front view of an apparatus for coating a belt for a belt type continuous casting machine used in the invention with a coating agent.

FIG. 2 is a diagram showing the relationship between the slab quality and the coating thickness when a coating agent is applied by the method of the present invention.

FIG. 3 is a diagram showing the relationship between the slab quality and coating film thickness variation when a coating agent is applied by the method of the present invention.

FIG. 4 is a schematic front view showing an example of a conventional twin belt type continuous casting machine.

FIG. 5 is a schematic front view of the twin-belt type continuous casting machine used in the example of the present invention, in which the coating device for coating the belt for the belt type continuous casting machine used in the present invention is incorporated.

[Explanation of symbols]

 1 Applicator roll 2 Pick-up roll 3 Meter roll 4 Scraper 5 Coating agent 6 Coating pan 7 Belt type continuous casting machine belt 8 Backup roll 11 Belt 12 Tundish 13 Nozzle 14, 15, 16 Pulley 17 Support roll 18 Molten metal 19 Slab 20 Mold (bath pool) 21 Cooling box

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B22D 11/04 312 B22D 11/04 312Z

Claims (2)

[Claims] 1. A coating agent tank for accommodating a coating agent, a pickup roll half-submerged in the coating agent in the tank, and an applicator supported in contact with both the pickup roll and the casting belt. Belt for continuous casting machine using a coating device comprising a roll, a meter roll supported in parallel with the pickup roll and maintaining a predetermined gap, and a scraper supported in parallel with and in contact with the meter roll. In the method for coating the coating agent on the inorganic coating agent, a solid content ratio of 40 to 60%,
A slurry having an average particle diameter of 30 to 50 μm is used, and the velocity vector of the applicator roll and the belt at the contact point of the belt type continuous casting machine, the velocity vector of the both at the contact point of the pickup roll and the applicator roll, and the pickup roll and the meter roll. To the belt for a continuous casting machine, characterized in that the velocity vectors of the two at the points closest to each other are opposite to each other, and coating is performed with a coating thickness of 60 μm to 150 μm and a thickness accuracy of ± 30 μm. Coating method of coating agent. 2. The pressing force of the applicator roll to the belt is 1.2 kg / mm or more, the pressing force of the pickup roll and the applicator roll is 0.5 kg / mm or more, and the gap between the pickup roll and the meter roll is 100.
~ 200μm, the peripheral speed of the meter roll is 3 ~ 10mpm,
2. The method for coating a belt for a belt type continuous casting machine with a coating agent according to claim 1, wherein the peripheral speed of the pickup roll is set to 7 to 30 mpm.