阅读说明：本技术 一种硅钢生产用退火炉专用基材及制备方法 (Special base material for annealing furnace for silicon steel production and preparation method ) 是由 牛进才 郑兴龙 韩健华 孙红涛 陈勇 赵军周 王贵先 张跃丽 于 2019-10-28 设计创作，主要内容包括：本发明提供了一种硅钢生产用退火炉专用基材及制备方法,包括以下重量份的原料：煅烧焦40-50份,粉子料40-50份,沥青30-35份,硬脂酸0.2-0.3份。通过改进生产工艺与生产流程。由于该产品的特殊要求,因此从配料,混捏凉料到焙烧,浸渍,石墨化等多个工序和流程都要重新制定出一套全新的合理的生产工艺和生产流程。本发明石墨化处理后的产品抗折强度≥18,肖氏硬度为35-50,抗压强度≥35,最大孔径≤0.1mm,气孔率≤11,体积密度≥1.75,石墨化度为70-90。(The invention provides a special substrate for an annealing furnace for silicon steel production and a preparation method thereof, wherein the special substrate comprises the following raw materials in parts by weight: 40-50 parts of calcined coke, 40-50 parts of powder material, 30-35 parts of asphalt and 0.2-0.3 part of stearic acid. By improving the production process and the production flow. Due to the special requirements of the product, a set of brand new and reasonable production process and production flow are required to be newly made from the processes of batching, kneading and cooling the materials to roasting, dipping, graphitizing and the like. The product after the graphitization treatment has the breaking strength of more than or equal to 18, the Shore hardness of 35-50, the compressive strength of more than or equal to 35, the maximum aperture of less than or equal to 0.1mm, the porosity of less than or equal to 11, the volume density of more than or equal to 1.75 and the graphitization degree of 70-90.)

1. The special base material for the annealing furnace for silicon steel production is characterized by comprising the following raw materials in parts by weight: 40-50 parts of calcined coke, 40-50 parts of powder material, 30-35 parts of asphalt and 0.2-0.3 part of stearic acid.

2. The special substrate for the annealing furnace for silicon steel production according to claim 1, wherein the calcined coke comprises: 30-40 parts of 0-0.5mm calcined coke and 10-20 parts of 0.5-1mm calcined coke.

3. The special substrate for the annealing furnace for silicon steel production according to claim 1 or 2, characterized in that: the ash content in the calcined coke is less than or equal to 0.3 percent, the water content is less than or equal to 0.5 percent, the volatile matter is less than or equal to 0.5 percent, the sulfur content is less than or equal to 0.45 percent, and the true density is more than or equal to 2.09g/cm³Tap density is more than or equal to 0.88g/cm³The resistivity is less than or equal to 450 mu omega m.

4. The special substrate for the annealing furnace for silicon steel production according to claim 3, characterized in that: the asphalt is modified asphalt, wherein the ash content of the modified asphalt is less than or equal to 0.03 percent, the water content of the modified asphalt is less than or equal to 0.3 percent, the coking value is more than or equal to 57 percent, the toluene insoluble substance is 28-35 percent, the softening point is 104-.

5. The special substrate for the annealing furnace for silicon steel production according to claim 3, characterized in that: the particle size of the powder is less than 0.075 mm.

6. The method for preparing the special substrate for the annealing furnace for silicon steel production as set forth in claim 4 or 5, characterized by comprising the steps of:

(1) dry mixing: heating the raw materials except the asphalt to 160-165 ℃ for dry mixing for 50-55min, adding the asphalt for wet mixing for 40-50min at 170-175 ℃, and cooling to 120-130 ℃ for cooling;

(2) prepressing the cooled material, and vacuumizing after prepressing;

(3) feeding the material subjected to vacuum treatment in the step (2) into an extruder for extrusion treatment;

(4) roasting the extruded material in a two-leaching three-roasting mode, and graphitizing after roasting to obtain the special base material.

7. The method for preparing the substrate special for the annealing furnace for silicon steel production as claimed in claim 6, wherein the pre-pressing pressure in the step (2) is 23 MPa; the vacuum degree is less than or equal to-0.08 MPa, and the vacuum is maintained for 100 s.

8. The method for preparing the special substrate for the annealing furnace for silicon steel production according to claim 6, wherein the method comprises the following steps: in the step (3), the extrusion speed is 1200mm/min, and the extrusion pressure is 6-10 MPa.

9. The method for preparing the special substrate for the annealing furnace for silicon steel production according to claim 6, wherein the specific steps of the two-dipping and three-roasting in the step (4) are as follows:

(a) roasting the extruded material at 1150-1200 ℃, and placing the roasted material into the modified asphalt for primary impregnation treatment;

(b) roasting the impregnated material in the step (a) at 1150-1200 ℃, and secondarily impregnating the roasted material in the modified asphalt;

(c) roasting the material subjected to the dipping treatment in the step (b) at 1150-1200 ℃, and graphitizing the roasted material to obtain the special base material.

10. The method for preparing the substrate special for the annealing furnace for silicon steel production as claimed in claim 9, wherein the temperature in the step (a) is raised from room temperature for 360h to 1150-1200 ℃, and the material weight gain rate after one-time dipping is 12-15%; the temperature of the steps (b) and (c) is increased from room temperature for 240h to 1150-1200 ℃, and the weight gain rate of the secondary impregnation is 6-8%.

Technical Field

The invention relates to the field of silicon steel production, in particular to a special base material for an annealing furnace for silicon steel production and a preparation method thereof.

Background

The cold-rolled silicon steel strip is decarbonized and recrystallized in a continuous roller hearth type annealing furnace, and a hearth roller used for steel strip transmission annealing in the furnace is mainly a graphite carbon sleeve. In the actual production process of silicon steel continuous annealing, due to the quality problem of the carbon sleeve, after the carbon sleeve is used for a period of time, the carbon sleeve is subjected to nodulation, abrasion, oxidation, loosening and peeling to cause abnormal damage, and the carbon sleeve often has to be processed or replaced on line, so that a large amount of energy media are wasted. Not only can seriously affect the production efficiency and the product quality, but also causes great economic loss to silicon steel production enterprises.

The carbon sleeve is generally at 800-1000 ℃, even 1050 ℃ high temperature and H₂-N₂-H₂The O is used for a long time under the condition of weak oxidizing atmosphere, and the phenomena of nodulation, oxidation, looseness, shedding and the like can not occur. Whereas graphite typically begins to oxidize at around 450 c. Although the graphite electrode used as the carbon roller substrate is used after being subjected to anti-oxidation treatment, the quality of the graphite electrode used as the substrate directly determines the final service life of the carbon sleeve.

Because the quality requirements of the graphite electrode for the carbon roller are greatly different from the quality requirements of the traditional graphite electrode, the qualified graphite electrode as the carbon roller substrate cannot be produced by the traditional electrode production process.

The main differences are the following:

(1) the surface structure requirements are different, the traditional product has no strict requirements on holes and the like on the surface, and the carbon roller requires that the number of holes larger than 2mm on the surface of the base material cannot exceed two.

(2) The requirements for surface hardness are different, and the traditional product requires that the lower the graphitization resistivity is, the better, and the corresponding surface hardness is also low, but the product requires that the hardness is in a reasonable range, which can not be too high or too low.

(3) The maximum diameter of the air hole, impurity elements and the like are different. Because of such strict requirements, there are few enterprises producing the product at home and abroad, the product yield is not more than 60%, and the technology is strict and confidential and the selling price is extremely high.

Therefore, the product is researched and developed by various enterprises such as overseas Japan, Korea and domestic eight-three-carbon, smooth carbon and the like, and the other enterprises except the product of a certain Japan enterprise have abandoned the development and production due to low finished product rate and high manufacturing cost caused by the reasons of overproof final product surface holes, insufficient hardness, unqualified structure and the like. So that domestic silicon steel production enterprises have to purchase a large amount of products in Japan and other countries at high price.

Disclosure of Invention

The invention provides a special base material for an annealing furnace for silicon steel production and a preparation method thereof, and improves the production process and the production flow. Due to the special requirements of the product, a set of brand new and reasonable production process and production flow are required to be newly made from the processes of batching, kneading and cooling the materials to roasting, dipping, graphitizing and the like.

The technical scheme for realizing the invention is as follows:

the special base material for the annealing furnace for silicon steel production comprises the following raw materials in parts by weight: 40-50 parts of calcined coke, 40-50 parts of powder material, 30-35 parts of asphalt and 0.2-0.3 part of stearic acid.

The calcined coke comprises: 30-40 parts of 0-0.5mm calcined coke and 10-20 parts of 0.5-1mm calcined coke.

The ash content in the calcined coke is less than or equal to 0.3 percent, the water content is less than or equal to 0.5 percent, the volatile matter is less than or equal to 0.5 percent, the sulfur content is less than or equal to 0.45 percent, and the true density is more than or equal to 2.09g/cm³Tap density is more than or equal to 0.88g/cm³The resistivity is less than or equal to 450 mu omega m.

The asphalt is modified asphalt, wherein the ash content of the modified asphalt is less than or equal to 0.03 percent, the water content of the modified asphalt is less than or equal to 0.3 percent, the coking value is more than or equal to 57 percent, the toluene insoluble substance is 28-35 percent, the softening point is 104-.

The particle size of the powder is less than 0.075 mm.

The preparation method of the special base material for the annealing furnace for silicon steel production comprises the following steps:

(1) dry mixing: heating the raw materials except the asphalt to 160-165 ℃ for dry mixing for 50-55min, adding the asphalt for wet mixing for 40-50min at 170-175 ℃, and cooling to 120-130 ℃ for cooling;

(2) prepressing the material after the material standing, and vacuumizing after the prepressing;

(3) feeding the material subjected to vacuum treatment in the step (2) into an extruder for extrusion treatment;

(4) roasting the extruded material in a two-leaching three-roasting mode, and graphitizing after roasting to obtain the special base material.

The pre-pressing pressure in the step (2) is 23 MPa; the vacuum degree is less than or equal to-0.08 MPa, and the vacuum is maintained for 100 s.

In the step (3), the extrusion speed is 1200mm/min, and the extrusion pressure is 6-10 MPa.

The two-leaching three-roasting step (4) comprises the following specific steps:

(a) roasting the extruded material at 1150-1200 ℃, and placing the roasted material into the modified asphalt for primary impregnation treatment;

(b) roasting the impregnated material in the step (a) at 1150-1200 ℃, and secondarily impregnating the roasted material in the modified asphalt;

(c) roasting the material subjected to the dipping treatment in the step (b) at 1150-1200 ℃, and graphitizing the roasted material to obtain the special base material.

In the step (a), the temperature is raised from room temperature for 360h to 1150-1200 ℃, and the weight gain rate of the material after primary impregnation is 12-15%; the temperature of the steps (b) and (c) is increased from room temperature for 240h to 1150-1200 ℃, and the weight gain rate of the secondary impregnation is 6-8%.

The invention has the beneficial effects that:

(1) the product after graphitization treatment has the breaking strength of more than or equal to 18, the Shore hardness of 35-50, the compressive strength of more than or equal to 35, the maximum aperture of less than or equal to 0.1mm, the porosity of less than or equal to 11, the volume density of more than or equal to 1.75 and the graphitization degree of 70-90;

(2) according to the invention, through the treatment of the formula, the structure compactness, low porosity and no pore larger than 2mm on the surface can be effectively improved, so that the maximum aggregate granularity of the formula is required to be 1mm, and a proper amount of surfactant is added into the binder;

(3) the invention solves the problems of carbon sleeve nodulation, oxidation, looseness, shedding and the like of the graphite electrode, improves the quality and performance of the product and finally improves the success rate of the product.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments of the present invention, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive effort based on the embodiments of the present invention, are within the scope of the present invention.