JPS58149977A - Highly corrosion-resistant and highly airtight packing material - Google Patents

Abstract

PURPOSE:To provide a packing material excellent in corrosion resistane to molten steel, airtightness and strippability, prepared by adding low-melting metal to a compsn. consisting of refractory powder and fiber and mot containing plasticizer. CONSTITUTION:The packing material is prepared by adding 0.5-20wt% low- melting metal (e.g. Al) in a particle size of about 3.0mm. or smaller to a compsn. which consists of at least one refractory powder (e.g. alumina/silica or magnesia/alumina) and fiber (ordinary inorganic, organic or metallic fiber) and contains no plasticizer. It has excellent corrosion resistance to molten steel, airtightness and strippability. Addition of 0.01-3wt% material which expands under heating (e.g. expandable polystyrene or expandable graphite) improves airtightness, for voids in the packing material are filled therewith.

Description

[Detailed Description of the Invention] Hon E! The present invention relates to a backing material with good corrosion resistance, airtightness, and peelability against AFi and molten steel.

It is divided into refractories for the main rope, which holds the molten copper pipe and supplies it to the tundish, and refractories for the tundish.

The means for controlling the flow rate of molten steel from the parent rope to the tundish and from the tundish to the mold has shifted from a one-stopper type to a sliding nozzle type.

For example, in the sliding nozzle system of the main line, mortar is usually used to connect the tuyere brick and the upper nozzle, the upper nozzle and the upper plate, and the lower plate and the lower nozzle. Further, a ceramic fiber sheet is usually used to connect the lower nozzle and the long nozzle because it must be easy to remove when replacing the pot. In addition, in the case of a tundish nozzle and a immersion nozzle
For the sliding nozzle method, mortar is usually used to connect the upper nozzle and the upper plate, and the lower plate and the intermediate nozzle, and ceramic fiber sheets are usually used to connect the intermediate nozzle and the immersion nozzle. It is used. The function of the backing material is extremely important when joining each brick to function as a single system. .

The disadvantages of mortar are that it requires skill, that the joints of the bricks are damaged when removing the mortar when replacing bricks, and that the airtightness is not sufficient. Also, the disadvantages of ceramic fibers are that they have poor corrosion resistance against molten steel and poor airtightness, and due to the work process, the fibers must be replaced in a short period of time.
However, at present, they are used with emphasis on workability such as ease of release.

This invention 8A#i was made to solve the problems of mortar and ceramic fiber sheets mentioned above,
Fi is preferably 5.0+n or less in a formulation consisting of at least 41 types of refractory powder and fibers and containing no plasticizer.
This is a highly corrosion-resistant and highly airtight backing material characterized by adding 0.5 to 20 weight of a low melting point metal with a particle size of 0 or less. This is a highly corrosion-resistant and highly airtight backing material characterized by adding an expanding material in an amount of 0.01 to S weight.

The gist of the present invention is to use a low melting point metal, such as Mut, at O,S~20
Weight - By adding it during formulation, Mut melts during use and captures oxygen in the air that has permeated into the backing material, resulting in A/40. Nasi, Mara, the volumetric expansion at this time fills the pores of the backing material and makes it denser.
Therefore, completely low air permeability has been achieved. In addition to low melting point metal #'iAt, Mg, Cu, Zn
etc., but considering the quantitative issues, handling issues, and corrosion resistance issues after becoming an oxide, Mut is optimal. Regarding the amount of Mut added, if it is less than 0.5 weight, the above-mentioned effect will not be obtained, and if it is more than 20 weight, the amount of melt generated will increase, making it impossible to maintain the structure of the backing material itself.

In this way, the addition of KAt alone can provide sufficient airtightness, but in addition, organic materials that expand when heated, such as those used in the production of expanded polystyrene, expanded polyethylene, and urethane, as well as inorganic materials such as expandable graphite and vermiculite, are added by 0.01%. By adding K to 5% by weight, it is possible to fill the pores of the backing material itself, and the airtightness becomes even better.

For example, expandable graphite becomes about 60 times its volume when heated rapidly. If the amount added is less than 0.01 weight, the above-mentioned effect will not be obtained, and if the amount added is 5 weight or more, the structure of the backing material itself cannot be maintained.

As the refractory powder, one or more of metal oxides, metal carbides, and metal nitrides can be used, including alumina-silica, magnesia-based powder, etc.
There are alumina series, magnesia-chromite series, magnesia-mag-chromite series, magnesia-calcia series, zirconia-silica series, silica-alumina-silica series, silicon nitride-alumina-silica series, and the like.

By using a refractory powder such as kyanite, which expands when heated, as an alumina-silica system,
It is possible to fill the pores of the backing material itself9, resulting in even better airtightness. The addition of J11 tensile material has the effect of improving the airtightness of the backing itself and at the same time improving the airtightness between the backing and the bricks, and has a double effect of preventing air from entering.

The amount of kyanite added is preferably 1 to 30% by weight, and 1 to 30% by weight.
If the amount is less than the weight, it will not be effective, and if the amount exceeds the weight, it will weaken the tissue and have the opposite effect.

Furthermore, a feature of the present invention is that it does not contain plasticizers such as viscosity and bentonite. The use of clay and bentonite is good in terms of shape retention, but in order to achieve the softness required for the backing material, the amount of binder added has to be increased, resulting in problems with smoking and shrinkage due to heating. It is not used because of the problem.

The fibers can be ordinary inorganic, organic, metal, etc.

As for the amount added, a larger amount is better in terms of the malleability and tensile strength of the backing material, but an appropriate amount of 5 to 10% by weight is appropriate depending on the blending condition at the time of crosstalk.

The binder can be inorganic or organic, such as sodium hexametaphosphate, sodium tripolyphosphate, sodium birophosphate, phenol resin, furan resin, epoxy resin, or silicone resin, but it does not matter if the binder is mixed during crosstalk or storage. Among inorganic materials, condensed sodium phosphate is preferred for rounding that does not change to At(OH), and among organic materials, phenolic resin is preferred due to its high residual carbon content and cost.

Alcohols, ketones, and esters due to viscous glands
It may be optionally diluted with a diluent.

This backing material can be used in the same manner as mortar, or it can be preformed and used in the same manner as ceramic fiber sheets. Depending on where and where it is used,
An important characteristic is the peelability when replacing bricks. For example, when replacing bricks, if the backing material does not adhere to the lower nozzle @K in the case of a long nozzle and a lower nozzle, and to the immersed nozzle side in the case of a submerged nozzle and an intermediate nozzle, subsequent processes will be hindered. Therefore, there is a method of applying a mold release material to the dowel surface of the long nozzle or intermediate nozzle, or a method of applying a mold release material such as water-based or oil-based graphite, molybdenum disulfide, tfCFi, boron nitride, etc. to one side of the molded backing material. It can be treated by coating.

Examples of the present invention will be described below.

Example 1 Sintered alumina 1 ■l or less SO weight - 1 525 mesh or less 60 weight - 1 Aj 0.28 or less 10 weight -, ceramic fiber outer layer 6 weight -, carbon powder outer layer 1
Weight -, phenol resin/ethylene recall (4/1
) was thoroughly kneaded with a mixer, rolled out to a predetermined thickness, and used for each measurement.

Example 2 Magnesia clinker-1At 30% by weight, 525 mesh L or less 60% by weight-1Ato, 20 or less 10% by weight,
Ceramic fiber outer layer: 6 weight, carbon powder outer layer: 1 weight, phenol resin/ethylene glycol
(4/1) and 1) were thoroughly kneaded with a mixer, rolled to a predetermined thickness, and used for each measurement.

Example 3 Spinel (MgO・At40.) 11 intestines or less 30 weight -
1 same i$25/7 shu or less 60 ts, At0,211
1 or less 10% by weight Ceramic fiber outer layer: 6 weight - Carbon powder outer layer: 1 weight - Phenol resin/
Ethylene glycol (4/1) was thoroughly kneaded using a zz-type mixer, and the mixture was prepared to a predetermined thickness and used for each measurement.

Example 4 30 weight below 1 layer of chromite - 1 60 weight below 325 mesh - 10 weight % under AtO92At, 6 weight % on ceramic fiber outer layer, 1 weight on carbon powder outer layer, phenol resin/ethylene glycol (4/ 1
) was thoroughly kneaded with a mixer, rolled out to a predetermined thickness, and used for each measurement.

Example 5 Artificial mag/black raw material 1111 or less 50 weight - 1 same 525
60 weight less than mesh, MutO, 10 weight less than 2ml, Ceramic Phino (-6 weight with outer layer, 1 weight with carbon powder outer layer), 22 weight S with outer layer of phenol resin/ethylene glycol (4/1) The mixture was thoroughly kneaded with a mixer, rolled out to a predetermined thickness, and used for each measurement.

Example 6 Zircon sand 30 weight, zircon flour 60 weight, MutO, 2m1m or less 10 weight, ceramic fiber outer layer 6 weight, carbon powder outer layer - 't' [c
Amount L Phenol resin/ethylene glycol (4/1
) was thoroughly kneaded with a mixer, rolled out to a predetermined thickness, and used for each measurement.

Example 7 Zirconia 1 - 30 weight - 1 325 mesh or less 60 weight - 1 AtO, 2111 or less 10 weight -, ceramic fiber outer layer 6% by weight, carbon powder outer layer 1 weight -, phenol range / ethylene glycol (4
/1) A mixture of 22 parts by weight was thoroughly kneaded with a mixer, rolled out to a predetermined thickness, and used for each measurement.

Example 8 Silica stone less than 1 haze! 10% by weight, 525 mesh L or less 60
Weight -, 10 weight less than 02m, 6 weight with ceramic fiber outer cover, 1 weight with carbon powder outer cover
G, phenol resin/ethylene glycol (4/1)
A 22-weight sample was thoroughly kneaded using a kneader, rolled to a predetermined thickness, and used for each measurement.

Example 9 Sintered alumina 1 to 60% by weight, magnesia 325 mesh or less by 60% by weight, 5AtO, 2111 or less by 10% by weight, 6% by weight for ceramic fiber outer layer, 1% by weight for carbon powder outer layer, phenol resin/ethylene glycol ( 4/1) Thoroughly knead 22% of the dough using an external W, roll it out to a predetermined thickness, and use it for each measurement.

Example 10 Chromite I I1m or less sO weight-, magnesia 525
60 weight below mesh - 10 weight below 1 Atojss -
, 6% by weight with ceramic fiber outer cover, Car M711
1 weight of phenol resin/ethylene glycol (4/1) was thoroughly kneaded, rolled out to a predetermined thickness, and used for each measurement.

Example 11 Artificial mag/black raw material 1 ■ 1 or less 30 weight bags, magnesia 525 mesh or less 60 weight - 1 At0.2 + U or less 1
0% by weight, 6mm 1iqIi with ceramic fiber outer cover
, 1 weight of carbon powder and 1 weight of phenol resin/ethylene glycol (4/1) were used for each measurement.

Example 12 Artificial tolomite raw material 1 ml or less 50 weight -, magnesia 525 m2 0 weight - 1 At 0, 2 weight m or less 1
0 weight, 6% by weight for the ceramic fiber outer layer, 1 weight% for the carbon powder outer layer, and 22 weight% for the phenol resin/ethylene glycol (4/1) outer layer,
It was rolled out to a predetermined thickness and used for each measurement.

Example 1s Zircon sand 501 amount s, zirconia 325 mesh or less 60 weight, MutO82u or less 10 weight, ceramic fiber outer layer 6 weight, carbon powder outer layer 1
Heavy! 22 weight of phenol resin/diethylene glycol (4/1) was thoroughly kneaded, rolled out to a predetermined thickness, and applied to each #j foot.

Example 14 Silicon carbide I IIm or less 50 weight - 1 325 mesh or less 60 weight - 1 A /, 0.21 or less 10 weight %, ceramic fiber outer layer 6 weight - carbon powder outer layer 1 weight -, phenol resin / ethylene glycol(
4/1) 22 weight pieces were thoroughly kneaded using a sokoguri, ground to a predetermined thickness, and used for each measurement.

Example 15 Silicon nitride 1 ml or less 50% by weight, 525 mesh or less 0 layers, MutO, 2u or less 10% by weight, 6% by weight outside W of carbon powder, W outside carbon powder 1% by weight, phenol resin/ethylene glycol (4
/1) A 22-wt.

Example 16 Sintered alumina 30% by weight or less, sintered alumina 525
50% by weight of mesh or less, 10% by weight of kyanite 0.2mm or less, 10% of AtO02am or less, ceramic fiber outer layer 6 weight j1%, carbon powder outer layer 1
Weight -, phenol resin/diethylene glycol (9
/1) 21% by weight was thoroughly kneaded using a mixer, rolled out to a predetermined thickness, and used for each measurement.

Example 17 One side of the molded body obtained in Example 2 was coated with a water-soluble graphite mold release material.

Example 18 Sintered alumina I ml or less 5 meshes 525 or less 50% by weight, kyanite 0, 2
11 or less 10% by weight, Al O02 u or less 10% by weight
, 1% by weight of carbon powder outer layer and 15% by weight of silicone resin outer layer are thoroughly kneaded with a mixer, rolled out to a predetermined thickness, and coated with water-based pyrolead on one side of the obtained molded body. A mold release agent was applied.

Comparative example 1 Conventional high alumina mortar.

Comparative Example 2 Conventional Ceramic Fiber Sheet The quality measurement results of the above backing material are shown in Table 1. In order to investigate the melt stability in hot conditions, we used alumina-graphite brick diameter! Cut out a sample of 0111, 3011n, cut it by half molecule C from the center,
During this time, insert backing material with a joint thickness of 51 m, and
, medium load 4. A load softening test was conducted under the condition of Okg/ad, and the measured values of only the backing material are shown after correcting the dimensional changes of the bricks themselves.

The peelability was judged by the ease with which the brick and banking material separated after the above-mentioned load softening test.

The ventilation rate is based on a sample shape with a diameter of 50 mm and a height of 60 mm.
After heat treatment at 10OC for 24 hours and at 1400℃ for 2 hours in saponification atmosphere, it was subjected to evaluation.

Corrosion resistance against molten iron was tested by cutting a brick in half for a rotary corrosion test, inserting backing material with a joint thickness of 4 km, and using low-viscosity pig iron. The depth of penetration of molten iron, t-#J, was added.

Table 1 @ Comparing with Comparative Examples 1 and 2, it has excellent melt stability in hot conditions, good corrosion resistance against pig iron, and low air permeability. Examples 17 and 18 also have good releasability. This backing material was used at Company A between the intermediate nozzle and the immersion nozzle of the evening/dish, maX, 8 charge, for approximately 7 hours. As a result, there was no air entrainment, and it was as good as conventional mortar or ceramic fiber sheet. I was able to achieve good results that I could not have obtained otherwise. In addition, by applying mold release material to the dowel part of the intermediate nozzle, it will adhere to the immersion nozzle side when bricks are replaced, and the above-mentioned peeling problem will be avoided. It can also be used for other purposes.

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Claims (1)

[Claims] Corrosion resistance against molten metal and airtightness characterized by adding 0.5 to 20% by weight of a low melting point metal to a formulation that does not contain at least one kind of refractory powder and a layer material such as fibers. Good backing material.