阅读说明：本技术 钢包无碳浇注水口及其制备方法 (Carbon-free pouring nozzle of steel ladle and preparation method thereof ) 是由 王玉龙 刘光平 程文雍 于 2019-10-30 设计创作，主要内容包括：本申请公开了一种钢包无碳浇注水口及其制备方法,以质量份计,所述钢包无碳浇注水口的原料包括：刚玉：37～76份；锆莫来石：0～16份；莫来石：0～8份；氧化铝微粉：10～16份；铝酸钙水泥：1～6份。本申请的钢包无碳浇注水口利用莫来石的针状晶体结构和氧化锆的晶格转变特点,提高了钢包无碳浇注水口的材料的热震稳定性能,改善了在使用过程中出现的开裂问题,延长了钢包无碳浇注水口的使用寿命。(The application discloses a carbon-free pouring nozzle of a ladle and a preparation method thereof, and the carbon-free pouring nozzle of the ladle comprises the following raw materials in parts by mass: corundum: 37-76 parts of; zirconium mullite: 0-16 parts of a solvent; mullite: 0-8 parts of a solvent; alumina micropowder: 10-16 parts; calcium aluminate cement: 1-6 parts. The ladle carbon-free pouring nozzle improves the thermal shock stability of the material of the ladle carbon-free pouring nozzle, improves the cracking problem in the using process and prolongs the service life of the ladle carbon-free pouring nozzle by utilizing the acicular crystal structure of mullite and the lattice transition characteristics of zirconia.)

1. The carbon-free pouring nozzle for the ladle is characterized by comprising the following raw materials in parts by mass:

2. the carbon-free pouring nozzle for a ladle according to claim 1, wherein Al in said corundum₂O₃Not less than 99.2 wt%; the corundum has the following grain size distribution in parts by mass:

3. the ladle carbon-free pouring nozzle according to claim 1, wherein ZrO in the zirconium mullite₂30 to 40 weight percent.

4. The carbon-free ladle nozzle according to claim 1, wherein the mullite is one or both of fused 70 mullite and sintered 70 mullite.

5. The carbon-free pouring nozzle for the steel ladle as claimed in claim 1, wherein the alumina micropowder is selected from at least one of the following specifications according to the difference of median particle diameter D50:

the specification A and the median particle diameter D50 are 0.5-1 μm;

specification B, median particle diameter D50 is 1-2 μm;

the specification C and the median particle diameter D50 are 4-5 μm.

6. The ladle carbon-free pouring nozzle according to claim 1, wherein the raw materials of the ladle carbon-free pouring nozzle comprise, in parts by mass:

7. the ladle carbon-free pouring nozzle according to claim 6, wherein the raw materials of the ladle carbon-free pouring nozzle comprise, in parts by mass:

8. the ladle carbon-free pouring nozzle according to claim 7, wherein the raw materials of the ladle carbon-free pouring nozzle comprise, in parts by mass:

9. the ladle carbon-free pouring nozzle according to claim 8, wherein the raw materials of the ladle carbon-free pouring nozzle comprise, in parts by mass:

10. the method for preparing the carbon-free pouring nozzle of the ladle as claimed in claims 1 to 9, comprising the steps of:

mixing corundum, zircon-mullite, alumina micropowder and calcium aluminate cement, uniformly mixing, discharging, filling into a nozzle mould for vibration, and then placing into a curing room for curing at 30-40 ℃ to obtain the carbon-free pouring nozzle of the ladle.

Technical Field

The application relates to the technical field of refractory materials, in particular to a carbon-free pouring nozzle of a ladle and a preparation method thereof.

Background

With the development of steel products, particularly low-carbon steel and ultra-low-carbon steel, the carburization amplitude of molten steel is large in the carbon-containing working layer of the steel ladle after decarburization is finished, and the development of the low-carbon steel and the ultra-low-carbon steel cannot be met. The ladle nozzle is used as a channel for communicating the ladle and the tundish, and the traditional mechanically-pressed carbon-containing nozzle can cause the problem of recarburization of molten steel. At present, a small amount of carbon-free water gaps are made of corundum-spinel materials, and the materials are seriously cracked after being used due to poor thermal shock stability, so that the use safety and the service life of the water gaps are influenced.

Disclosure of Invention

In order to solve the problems in the prior art, corundum and mullite are selected as main raw materials, and zirconia is introduced into the raw materials, so that the thermal shock stability of the carbon-free ladle nozzle can be improved, the cracking problem in the using process is solved, and the service life of the carbon-free ladle nozzle is prolonged.

The application provides a ladle carbon-free pouring nozzle, by mass, the raw materials of ladle carbon-free pouring nozzle include:

optionally, Al in said corundum₂O₃Not less than 99.2 wt%; the corundum has the following grain size distribution in parts by mass:

optionally, ZrO in the zirconium mullite₂30 to 40 weight percent.

Optionally, the mullite is one or both of fused 70 mullite and sintered 70 mullite.

Optionally, the alumina micropowder is selected from at least one of the following specifications according to the difference of median particle size D50:

the specification A and the median particle diameter D50 are 0.5-1 μm;

specification B, median particle diameter D50 is 1-2 μm;

the specification C and the median particle diameter D50 are 4-5 μm.

Optionally, the calcium aluminate cement is one or two of 70 pure calcium aluminate cement and 80 pure calcium aluminate cement.

Optionally, the particle size of the calcium aluminate cement is less than or equal to 0.044mm, the initial setting time is more than 1.5h, and the final setting time is less than 6 h.

Optionally, the raw materials of the carbon-free pouring nozzle of the ladle comprise, by mass:

optionally, the raw materials of the carbon-free pouring nozzle of the ladle comprise, by mass:

optionally, the raw materials of the carbon-free pouring nozzle of the ladle comprise, by mass:

optionally, the raw materials of the carbon-free pouring nozzle of the ladle comprise, by mass:

the application also provides a preparation method of the ladle carbon-free pouring nozzle, which comprises the following steps:

mixing corundum, zircon-mullite, alumina micropowder and calcium aluminate cement, uniformly mixing, discharging, filling into a nozzle mould for vibration, and then placing into a curing room for curing at 30-40 ℃ to obtain the carbon-free pouring nozzle of the ladle.

The carbon-free pouring nozzle of the steel ladle at least has one of the following technical effects: the carbon-free pouring nozzle of the ladle adopts corundum and mullite as main raw materials, and no carbon element is introduced into the raw materials, so that the problem of recarburization of molten steel is relieved, and the requirements of a steel mill for smelting low-carbon steel and ultra-low-carbon steel are met; meanwhile, zirconia is introduced into the raw materials, and the thermal shock stability of the material is improved, the use safety is improved, and the service life is prolonged by utilizing the acicular crystal structure of mullite and the lattice transition characteristics of zirconia.

Detailed Description

The present application is further illustrated by the following examples.

An embodiment of the application provides a ladle carbon-free pouring nozzle, and the raw materials of the ladle carbon-free pouring nozzle comprise by mass: corundum; 37-76 parts of; zirconium mullite: 0-16 parts of a solvent; mullite: 0-8 parts of a solvent; alumina micropowder: 10-16 parts; calcium aluminate cement: 1-6 parts.

In this example, corundum and mullite were selected as the main materials for the pouring nozzle, because Al is present in₂O₃-SiO₂In the binary phase diagram, the low melting point temperature is 1840 ℃, which can meet the use temperature of molten steel smelting; meanwhile, the acicular crystal structure of the mullite can provide good thermal shock stability for the material for the pouring nozzle.

Zirconium mullite is added into the raw materials, and zirconium oxide is introduced, so that the carbon-free pouring nozzle is cracked due to thermal shock in the process of bearing molten steel impact mainly due to insufficient thermal shock performance in the process of damaging the carbon-free pouring nozzle. The introduction of the zirconia can form microcracks in the material for the carbon-free pouring nozzle through the crystal form transformation of the zirconia, and the existence of the microcracks can improve the fracture toughness of the material for the carbon-free pouring nozzle, resist the expansion of the cracks and be beneficial to improving the cracking problem of the carbon-free pouring nozzle in the using process.

The traditional material for pouring the water gap by combining cement and water is easy to crack in the using process due to volume change caused by hydration and dehydration of the cement, so that the safety of the water gap is reduced, and the service life of the water gap is prolonged. The application adopts a low-cement composite micro-powder combination system, and can relieve the volume change problem caused by the hydration process of cement and the dehydration of hydration products in a high-temperature environment. Meanwhile, the combination of the composite micro powder can improve the initial strength of the material and the sintering strength in a high-temperature working environment, and is beneficial to resisting the scouring of molten steel.

In another embodiment, Al in corundum₂O₃Not less than 99.2 wt%; the corundum has the following grain size distribution in parts by mass: 5-3 mm: 25-30 parts of a solvent; 3-1 mm: 2-10 parts; 1-0.088 mm: 0-21 parts; less than or equal to 0.088 mm: 10-15 parts.

As for the selection of corundum, either or both of plate corundum and fused white corundum may be selected. The plate-shaped corundum has a plate-shaped crystal structure, and has good thermal shock resistance and bending strength after being used for high-temperature treatment of produced refractory or castable. The corundum crystal grains of the electro-fused white corundum are complete and coarse, and have good chemical stability.

The range of particle size in the particle size grading is only to express different specifications of raw materials, and does not emphasize the composition after compounding.

Corundum with different particle sizes is selected and matched in the material for the pouring nozzle, so that the compactness of the material is met as much as possible on the premise of ensuring good construction performance of the pouring nozzle, and the service performance of the material is improved.

The raw materials of the following examples are composed of various particle size compositions, and all have the effects of meeting the compactness of the material and improving the service performance of the material.

In another embodiment, ZrO in zirconium mullite₂30 to 40 weight percent.

The zirconium mullite is composed of four grain size compositions of 3mm < grain size < 5mm, 1mm < grain size < 3mm, 0.088mm < grain size < 1mm and < 0.088 mm. One or more of these grain size grading compositions may also be used.

In another embodiment, the mullite is one or both of fused 70 mullite or sintered 70 mullite.

The mullite is composed of four grain size compositions of 3mm < grain size < 5mm, 1mm < grain size < 3mm, 0.088mm < grain size < 1mm and < 0.088 mm. One or more of these grain size grading compositions may also be used.

In another embodiment, the alumina micropowder is selected from at least one of the following specifications according to the difference of median particle diameter D50:

the specification A and the median particle diameter D50 are 0.5-1 μm;

specification B, median particle diameter D50 is 1-2 μm;

the specification C and the median particle diameter D50 are 4-5 μm. Wherein the alumina micro powder is active alumina micro powder.

In another embodiment, the calcium aluminate cement is one or both of 70 pure calcium aluminate cement and 80 pure calcium aluminate cement.

The 70 pure calcium aluminate cement is a hydraulic binder which is formed by sintering high-purity calcium oxide and aluminum oxide at high temperature, wherein the content of the aluminum oxide is 70%. The 80 pure calcium aluminate cement refers to a hydraulic binder with the content of alumina of 80%. The two have the characteristics of low impurity, high bonding strength and stable condensation time, and can endow the carbon-free pouring nozzle of the ladle with higher mechanical property and high-temperature resistance.

In another embodiment, the particle size of the calcium aluminate cement is less than or equal to 0.044mm, the initial setting time is more than 1.5h, and the final setting time is less than 6 h.

In another embodiment, the raw materials of the carbon-free pouring nozzle of the ladle comprise the following components in parts by mass: corundum; 37-76 parts of; zirconium mullite: 1-16 parts; mullite: 1-8 parts; alumina micropowder: 10-16 parts; calcium aluminate cement: 1-6 parts.

In a preferred embodiment, the raw materials of the ladle carbon-free pouring nozzle comprise the following components in parts by mass: corundum: 40-70 parts of a binder; zirconium mullite: 5-16 parts of a solvent; mullite: 5-8 parts; alumina micropowder: 10-16 parts; calcium aluminate cement: 1-6 parts.

In a preferred embodiment, the raw materials of the ladle carbon-free pouring nozzle comprise the following components in parts by mass: corundum: 49-62 parts; zirconium mullite: 7-16 parts; mullite: 5-8 parts; alumina micropowder: 14-16 parts of a solvent; calcium aluminate cement: 3-6 parts.

In a preferred embodiment, the raw materials of the ladle carbon-free pouring nozzle comprise the following components in parts by mass: corundum: 49-62 parts; zirconium mullite: 7-15 parts; mullite: 5-8 parts; alumina micropowder: 14-16 parts of a solvent; calcium aluminate cement: 3-4 parts.

The application also provides a preparation method of the ladle carbon-free pouring nozzle, which comprises the following steps:

mixing corundum, zircon-mullite, alumina micropowder and calcium aluminate cement, uniformly mixing, discharging, filling into a nozzle mould for vibration, and then placing into a curing room for curing at 30-40 ℃ to obtain the carbon-free pouring nozzle of the ladle.

Various embodiments of the present application and comparative examples are provided below.