Low-expansion corrosion-resistant material added with cerium boride and preparation method thereof
阅读说明：本技术 一种添加硼化铈的低膨胀耐侵蚀材料及其制备方法 (Low-expansion corrosion-resistant material added with cerium boride and preparation method thereof ) 是由 谭杜 骆忠文 鲍颢文 鲍志 于 2020-12-22 设计创作，主要内容包括：一种添加硼化铈的低膨胀耐侵蚀材料,属于连铸用含碳耐火材料技术领域,由以重量份数计的3-12份石墨0.2-0.4mm、20-55份氧化锆颗粒1-0.1mm、15-35份氧化锆细粉0.1-0.044mm、17-25份氧化锆细粉<0.044mm、5-10份结合剂<200目、5-10份硼化铈<10μm配制而成,不加金属抗氧化剂亦能防止制品氧化,减少金属抗氧化剂产生的Al-2O-3、SiO-2杂质,所制得材料具有膨胀系数低、热震稳定性能好、耐侵蚀性能优异等特点,能够大幅度延长浸入式水口使用寿命。(A low-expansion erosion-resistant material added with cerium boride belongs to the technical field of carbon-containing refractory materials for continuous casting, and comprises, by weight, 3-12 parts of graphite 0.2-0.4mm, 20-55 parts of zirconia particles 1-0.1mm, 15-35 parts of zirconia fine powder 0.1-0.044mm, and 17-25 parts of zirconia fine powder<0.044mm and 5-10 parts of bonding agent<200 mesh, 5-10 parts of cerium boride<10 μm, can prevent product oxidation without adding metal antioxidant, and reduce Al generated by metal antioxidant 2 O 3 、SiO 2 The prepared material has the characteristics of low expansion coefficient, good thermal shock stability, excellent erosion resistance and the like, and can greatly prolong the service life of the submerged nozzle.)
1. A low-expansion erosion-resistant material added with cerium boride is characterized by comprising the following raw material components in parts by weight:
0.2-0.4mm graphite 3-12 parts
20-55 parts of zirconia particles with the particle size of 1-0.1mm
0.1-0.044mm 15-35 parts of zirconium oxide fine powder
17-25 parts of zirconia fine powder with the particle size of less than 0.044mm
5-10 parts of bonding agent with the granularity of less than 200 meshes
5-10 parts of cerium boride less than 10 mu m.
2. The low-expansion erosion-resistant material added with cerium boride as claimed in claim 1, wherein the zirconia particles are at least one of zirconia, electrofusion-stabilized zirconia or calcium yttrium composite-stabilized zirconia.
3. The method of claim 1A low-expansion erosion-resistant material added with cerium boride, which is characterized in that ZrO in zirconia particles2≥94.0wt％。
4. The material of claim 1, wherein the cerium boride is CeB6>99%。
5. The material of claim 1, wherein the binder is an organic binder.
6. The material of claim 5, wherein the organic binder is a resin.
7. The method for preparing the low-expansion erosion-resistant material added with the cerium boride as in the claims 1 to 6, wherein the raw materials are mixed and granulated, then the material is compounded on the slag line part of the outer layer of the nozzle, and the mixture is pressed into a green body by isostatic pressing, and then the green body is fired at 800-1000 ℃ to obtain the finished product.
Technical Field
The invention belongs to the technical field of carbon-containing refractory materials for continuous casting, mainly relates to a low-expansion corrosion-resistant material added with cerium boride, and also provides a preparation method of the low-expansion corrosion-resistant material.
Background
In the development process of the steel industry, the development of the continuous casting process technology is not separated from the development of the refractory material for the continuous casting tundish. The submerged entry nozzle used in the current continuous casting process is generally made of resin-bonded Al2O3The slag line part material with erosion resistance mainly made of-C material is usually selected from zirconia, graphite and other materials, and added with SiC, Si, Al and other antioxidants, and is combined into zirconium carbon material by resin. The metal antioxidant in the traditional material is usedZrO will be formed in the process2Al in-C material2O3、SiO2Impurities, which also reduce the corrosion resistance of the material.
At present, the converter technology is continuously improved, the molten steel smelting rhythm is accelerated, and continuous casting is also pursued for high-pulling-speed production in order to better meet the matching requirement of a converter and a machine. Under the condition of continuous casting ultrahigh-pulling-speed production, when the continuous casting pulling speed is more than 4.0m/min or meets the highest pulling speed of 6m/min, the covering slag must be quickly dissolved, certain wettability needs to be kept, slag entrapment is prevented, the alkalinity of the covering slag must be more than or equal to 1.0, and the melting point is reduced to be within the range of 1000-1050 ℃; the requirement for erosion-resistant materials at the slag line part (the joint of molten steel and casting powder) of the submerged nozzle is higher and higher.
Conventional ZrO2the-C material is difficult to meet the high requirements of the continuous casting process, so the corrosion resistance is improved by increasing the content of zirconia, but the expansion coefficient is reduced by high thermal shock, the submerged nozzle is cracked just on line, the casting cannot be normally carried out, and the use requirement cannot be met, which becomes a difficult point in the continuous casting production process.
Chinese patent 2015101906639 discloses a method and equipment for preparing zirconia metering nozzle from cerium oxide micropowder, which comprises the steps of carrying out spray granulation on a binding agent and powder to obtain particles, carrying out recombination and separation on the particles to obtain a blank, and calcining the obtained blank at 1690-1700 ℃ to obtain the zirconia metering nozzle; the powder material is prepared from partially stabilized zirconia, monoclinic zirconia and cerium oxide micropowder according to the dosage ratio of (50-60): (40-50): (3-6), wherein the cerium oxide is added into the powder to serve as a stabilizing agent to play a role in phase change toughening, and the other important role is to serve as a sintering agent and a ceramizing agent to solve the problem of difficult sintering of the ceramic zirconia metering nozzle. The powder does not contain carbon material, has high sintering temperature, expansion coefficient and thermal shock stability, and is not suitable for the high requirements of a continuous casting submerged nozzle. And for the submerged nozzle made of carbon-containing materials, the prevention of nozzle oxidation cannot be realized only by adding cerium oxide.
Disclosure of Invention
The invention aims to overcome the defects and provides a boron-added materialThe cerium oxide low-expansion corrosion-resistant material can prevent the product from being oxidized without adding a metal antioxidant, and can reduce Al generated by the metal antioxidant2O3、SiO2The prepared material has the characteristics of low expansion coefficient, good thermal shock stability, excellent erosion resistance and the like, and can greatly prolong the service life of the submerged nozzle.
Cerium boride is a low expansion material with an expansion coefficient of only 6.2X 10-6K, and a coefficient of expansion of 11X 10-6In ZrO of2The expansion of the slag-resistant material is greatly reduced by adding certain quantitative cerium boride into the-C material, and the stability of the slag-resistant material is superior to that of the traditional ZrO2A material-C, the melting point of cerium boride is up to 2552 ℃, cerium oxide is formed by oxygen at high temperature after being mixed with zirconia, the cerium boride can be used as a stabilizer of the zirconia, and B is generated during oxidation2O3Liquid phase, which can close the pores in the product, prevent the product from oxidizing even in the absence of metal antioxidant, and reduce Al generated by the metal antioxidant2O3、SiO2Impurities and negative impact on article properties. With conventional ZrO2The expansion of the material is reduced, the thermal shock property is improved, and the anti-erosion effect is obvious.
The method is implemented specifically as follows: a low-expansion erosion-resistant material added with cerium boride is characterized by comprising the following raw material components in parts by weight:
0.2-0.4mm graphite 3-12 parts
20-55 parts of zirconia particles with the particle size of 1-0.1mm
0.1-0.044mm 15-35 parts of zirconium oxide fine powder
17-25 parts of zirconia fine powder with the particle size of less than 0.044mm
5-10 parts of bonding agent with the granularity of less than 200 meshes
5-10 parts of cerium boride less than 10 mu m.
The zirconia particles adopt at least one of zirconia, electrofusion stabilized zirconia or calcium-yttrium composite stabilized zirconia, and ZrO in the zirconia particles2Not less than 94.0 wt%, and the content of cerium boride CeB6>99%。
The binder is an organic binder such as a resin or the like.
The preparation method of the low-expansion corrosion-resistant material added with cerium boride comprises the following steps: mixing and granulating the raw materials, compounding the material at the outer layer slag line part of the water gap, pressing the mixture into a green body by isostatic pressing, and firing the green body at 800-1000 ℃ to obtain the finished product.
Under the condition that the alkalinity of the casting powder is higher, the cerium boride can obviously improve the turning temperature and the crystallization property of the casting powder, and the higher crystallization temperature enables the viscosity of the casting powder around a slag line to be increased and the erosion of the casting powder to the submerged nozzle to be obviously reduced in the using process of the submerged nozzle.
The erosion-resistant material prepared by the invention has the characteristics of low expansion coefficient, good thermal shock property, excellent slag erosion resistance and the like, and can greatly prolong the service life of the water gap.
Detailed Description
Example 1, a cerium boride-added low-expansion erosion-resistant material, by weight, is composed of 11 parts of 0.2-0.4mm graphite, 20 parts of 1-0.1mm zirconia particles, 35 parts of 0.1-0.044mm zirconia fine powder, 25 parts of <0.044mm zirconia fine powder, 10 parts of resin binder, and 9 parts of <10 μm cerium boride, and when in use, the raw materials are mixed and granulated, the material is compounded at the outer layer slag line part of a nozzle, and the mixture is pressed into a green body by isostatic pressing, and the finished product is fired at 800-1000 ℃.
The zirconia particles in the raw material adopt at least one of zirconia, electrofusion stabilized zirconia or calcium-yttrium composite stabilized zirconia, and ZrO in the zirconia particles2Not less than 94.0 wt%, cerium boride CeB699.0 wt% or more, and the binder is organic binder such as resin.
The performance test results of the low-expansion corrosion-resistant material added with cerium boride are shown in the table I.
In examples 2 to 4 and reference example 1, the weight parts of the raw materials and the performance test results of the cerium boride-added low-expansion corrosion-resistant material prepared are shown in the table.
In comparative examples 1 and 2, cerium boride was not added to the powder, and an antioxidant metal was added.
The actual use condition on site is divided into two groups, namely two shifts, and the field record is shown in a second table.
The first group of comparative examples 1 and 2, to which antioxidant metals were added, were used for a maximum time of 09 minutes in 10 hours and a minimum time of 55 minutes in 9 hours.
The second group of examples 1-4, in which the antioxidant metal was not added and cerium boride was added, were used for a period of time of up to 16 hours 05 minutes and up to 14 hours 13 minutes, which exceeded 14 hours.
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