阅读说明：本技术 一种冷连轧法生产无取向高硅钢的方法 (Method for producing non-oriented high-silicon steel by cold continuous rolling method ) 是由 高振宇 李元华 陈春梅 刘文鹏 罗理 孟昭萍 张仁波 李亚东 林棡 姜福健 于 2021-08-19 设计创作，主要内容包括：本发明涉及一种冷连轧法生产无取向高硅钢的方法,RH真空脱碳处理后,铝脱氧及部分铝合金化,合金化后大罐钢水净循环大于3次或大于5分钟；熔炼合格钢水至连铸开浇前静置时间大于二十分钟；控制过热度5～15℃；采用电磁搅拌,控制等轴晶比例45％以上；3)热轧工序板坯装炉温度大于750℃；常化使晶粒尺寸在90～110μm范围内；连续退火炉加热段温度设定950～1150℃,均热段温度设定900～1050℃,全氮气干气氛保护,控制晶粒尺寸120～170μm。生产全过程中的热履历参数控制,充分发挥设计的微合金元素功能,改变析出物的组成、大小、形态及分布。(The invention relates to a method for producing non-oriented high silicon steel by a cold continuous rolling method, which comprises the steps of carrying out aluminum deoxidation and partial aluminum alloying after RH vacuum decarburization treatment, and carrying out net circulation of large-tank molten steel for more than 3 times or more than 5 minutes after alloying; the standing time of the molten steel after the molten steel is smelted and before the continuous casting is started is more than twenty minutes; controlling the degree of superheat to be 5-15 ℃; electromagnetic stirring is adopted, and the isometric crystal proportion is controlled to be more than 45%; 3) the charging temperature of the plate blank in the hot rolling procedure is more than 750 ℃; normalizing to make the grain size within 90-110 μm; the temperature of the heating section of the continuous annealing furnace is set to 950-1150 ℃, the temperature of the soaking section is set to 900-1050 ℃, the temperature is protected by the full nitrogen dry atmosphere, and the grain size is controlled to be 120-170 mu m. The thermal history parameters in the whole production process are controlled, the designed functions of the microalloy elements are fully exerted, and the composition, the size, the form and the distribution of precipitates are changed.)

1. A method for producing non-oriented high silicon steel by a cold continuous rolling method is characterized in that the steel contains the following chemical components: c is less than or equal to 0.0027 percent, and Si: 1.70% -3.35%, Als: 0.20-1.0%, Mn: 0.20 to 0.8 percent of the total weight of the alloy, less than or equal to 0.012 percent of P, less than or equal to 0.0020 percent of S, less than or equal to 0.0020 percent of N, less than or equal to 0.0020 percent of Ti, less than or equal to 0.0020 percent of V, less than or equal to 0.0020 percent of Nb, and the content of B satisfies the following requirements: [B] -N + 1/2O, Sn/Sb: 0.04-0.12 percent of Fe and the balance of inevitable residual elements; the process route is as follows: the method comprises the following steps of molten iron desulphurization, converter smelting, RH refining, continuous casting, hot rolling, normalizing, acid washing, cold rolling, continuous furnace annealing, coating, performance inspection and packaging, and specifically comprises the following steps:

1) after RH vacuum decarburization treatment, aluminum deoxidation and partial aluminum alloying are firstly added according to the amount of the aluminum alloy of 1/3-1/2; then alloying the whole silicon steel, adding boron, supplementing the rest aluminum alloy, and adding tin;

2) after alloying, the net circulation of the large-tank molten steel is more than 3 times or more than 5 minutes; the standing time of the molten steel after the molten steel is smelted and before the continuous casting is started is more than twenty minutes; controlling the degree of superheat to be 5-15 ℃; electromagnetic stirring is adopted, and the isometric crystal proportion is controlled to be more than 45%;

3) hot rolling, wherein the charging temperature of the plate blank is more than 750 ℃;

4) the slab temperature of a soaking section of a hot-rolled slab heating furnace is 1000-1150 ℃, the finishing temperature is controlled at 830-930 ℃, and the coiling temperature is 650-750 ℃;

5) normalizing at 850-950 ℃, slowly cooling at 750-650 ℃ in the cooling process, and controlling the cooling speed to be less than 100 ℃/min to ensure that the grain size is within the range of 90-110 mu m;

6) carrying out acid pickling and finishing, then carrying out cold continuous rolling, preheating a steel strip to 50-150 ℃ before cold rolling, and rolling the steel strip to the thickness of a finished product by controlling the final reduction rate to be below 10%;

7) setting the temperature of a heating section of the continuous annealing furnace to be 950-1150 ℃, setting the temperature of a soaking section to be 900-1050 ℃, protecting the heating section by using a full nitrogen dry atmosphere, and controlling the grain size to be 120-170 mu m; in the cooling process, slowly cooling at the temperature of 800-650 ℃, and controlling the cooling speed to be less than 10 ℃/S.

Technical Field

The invention relates to the field of metallurgy, in particular to a method for producing non-oriented high-silicon steel by a cold continuous rolling method.

Background

The non-oriented high-grade silicon steel series products are important functional soft magnetic materials, have wide requirements along with the technical progress and the development of downstream industries, and gradually develop from the fields of large and medium industrial motors and generators to the fields of high-efficiency motors, high-efficiency compressors, new energy motors and the like.

At present, only a few large-scale steel and iron combination enterprises at home and abroad have high-grade silicon steel production technology and process equipment, and the capacity of the traditional production flow is limited. With the improvement of metallurgical technology and the improvement of technological equipment capacity, the high-grade silicon steel basically realizes a primary cold rolling method from a traditional secondary cold rolling method, the reversible rolling production of a high-rigidity single-stand rolling mill is converted into the production of a continuous rolling unit, and then the two-stage annealing is converted into the one-stage high-temperature rapid annealing process, so that the production efficiency and the yield index are greatly improved.

The continuous rolling method for producing high-grade non-oriented silicon steel faces several technical problems which need to be solved urgently, firstly, the brittleness of high-silicon steel is avoided, the influence of edge cracks and broken strips on continuous production is reduced, secondly, the change of internal structure caused by the change of the deformation mode of a steel plate directly influences the heat treatment process and the electromagnetic performance of a finished product, and the mechanism research and the special technical control on the system flow are needed. Domestic and overseas mainstream production enterprises produce high-grade varieties with high performance by a continuous rolling method by using own unique technology, so that the profitability and market competitiveness of the products are improved.

Disclosure of Invention

The invention aims to solve the technical problem of providing a method for producing non-oriented high-silicon steel by a cold continuous rolling method, so that the generation of strip breakage and edge crack is reduced, and the yield is improved.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for producing non-oriented high silicon steel by a cold continuous rolling method comprises the following chemical components: c is less than or equal to 0.0027 percent, and Si: 1.70% -3.35%, Als: 0.20-1.0%, Mn: 0.20-0.8%, O: 0.0045-0.0065%, P is less than or equal to 0.012%, S is less than or equal to 0.0020%, N is less than or equal to 0.0020%, Ti is less than or equal to 0.0020%, V is less than or equal to 0.0020%, Nb is less than or equal to 0.0020%, and B content satisfies: [B] -N + 1/2O, Sn or Sb: 0.04-0.12 percent of Fe and the balance of inevitable residual elements; the process route is as follows: the method comprises the following steps of molten iron desulphurization, converter smelting, RH refining, continuous casting, hot rolling, normalizing, acid washing, cold rolling, continuous furnace annealing, coating, performance inspection and packaging, and specifically comprises the following steps:

1) after RH vacuum decarburization treatment, aluminum deoxidation and partial aluminum alloying are firstly added according to the amount of the aluminum alloy of 1/3-1/2; then alloying the whole silicon steel, adding boron, supplementing the rest aluminum alloy, and adding tin;

2) after alloying, the net circulation of the large-tank molten steel is more than 3 times or more than 5 minutes; the standing time of the molten steel after the molten steel is smelted and before the continuous casting is started is more than twenty minutes; controlling the degree of superheat to be 5-15 ℃; electromagnetic stirring is adopted, and the isometric crystal proportion is controlled to be more than 45%;

3) hot rolling, wherein the charging temperature of the plate blank is more than 750 ℃, and the enrichment and segregation of tin among coarse cast structures are inhibited;

4) the slab temperature of a soaking section of a hot-rolled slab heating furnace is 1000-1150 ℃, the finishing temperature is controlled at 830-930 ℃, and the coiling temperature is 650-750 ℃;

5) normalizing at 850-950 ℃, slowly cooling at 750-650 ℃ in the cooling process, and controlling the cooling speed to be less than 100 ℃/min to ensure that the grain size is within the range of 90-110 mu m;

6) carrying out acid pickling and finishing, then carrying out cold continuous rolling, preheating a steel strip to 50-150 ℃ before cold rolling, and rolling the steel strip to the thickness of a finished product by controlling the final reduction rate to be below 10%;

7) setting the temperature of a heating section of the continuous annealing furnace to be 950-1150 ℃, setting the temperature of a soaking section to be 900-1050 ℃, protecting the heating section by using a full nitrogen dry atmosphere, and controlling the grain size to be 120-170 mu m; in the cooling process, slowly cooling at the temperature of 800-650 ℃, and controlling the cooling speed to be less than 10 ℃/S.

Description of the components:

c: the finished product is not decarburized, and is annealed in the full-nitrogen protective atmosphere, so that high-efficiency production is guaranteed;

si: a fully ferritic structure product at ultra-low carbon;

mn: reducing composite impurities and typical manganese sulfide precipitation coarsening;

s, N, Ti, V, Nb: controlling clean steel, playing the role of micro-alloy design elements and reducing the total amount of unfavorable carbonitrides;

b: the B has affinity with oxygen and nitrogen, is used as a nucleation core of composite inclusion and coarsening aluminum nitride, is matched with process control, and can play a role of substituting boron for aluminum in the traditional design, reduce the addition of main alloy aluminum elements and reduce the sensitivity of hot rolling heating temperature to electromagnetic performance;

sn, Sb: the process is matched with the process control, and the inclusion and the precipitation grain boundary precipitation are controlled; the grain boundary energy and the surface energy are reduced, the (111) texture component is inhibited, and the promotion of the texture component is facilitated; surface segregation, inhibition of oxidation and nitridation of the annealing surface and the near surface layer of the finished product, improvement of electromagnetic performance and convenience in cancellation of hydrogen protection; the crystal boundary composition is improved, the blocking effect on the growth of crystal grains is reduced, the coercive force is reduced, the magnetization is facilitated, and the hysteresis loss and the repeated loss are reduced; by matching with the process, the element is enriched in grain boundaries, so that the segregation and segregation of other fine inclusions and second-phase particles are prevented, the grain boundary strength is relatively reduced, the deformation resistance of a steel plate is reduced, the cold rolling processability is improved, and the rolling recovery rate of high-silicon steel is improved; the content of the precipitate with the diameter of more than 70nm is 30-45%, the influence on the magnetization process is reduced, and the beneficial magnetic property structure with proper size, uniform crystal grains and obvious coarsening of the precipitate is finally controlled by matching with the heat treatment process.

Compared with the prior art, the invention has the beneficial effects that:

1. through the design of micro-alloy elements, the alloy reduction of products with the same grade is carried out, the continuous rolling capability is improved, and the capability of high-grade products with high grade and high grade which can be produced by continuous rolling is improved.

2. By the design of micro-alloy elements, the control of texture components in the conversion from 'shear deformation' of a single stand to 'plate compression deformation' of continuous rolling is facilitated.

3. The thermal history parameters in the whole production process are controlled, the designed functions of the microalloy elements are fully exerted, the composition, the size, the form and the distribution of precipitates are changed, and the precipitates with the diameter of more than 70nm account for 30 to 45 percent.

4. Steel cleanliness control and main process control are adopted, and uniform deformation of the structure in the rolling process is realized, and stable production is realized; meanwhile, the stress concentration points and crack sources of the processing deformation are reduced, the grain boundary segregation and segregation are reduced, and the band breakage and edge crack generation in the rolling process are reduced.

5. The production of high-grade products of a continuous rolling unit reduces the generation of broken belts and edge cracks, and the yield is improved; the performance of the same-grade product is stably improved, and the competitiveness of the product is improved.

6. The main alloy is reduced, the performance is stably improved, and the continuous rolling production of higher-grade products is realized.

Detailed Description

The invention is further illustrated by the following examples:

the following examples describe the invention in detail. These examples are merely illustrative of the best embodiments of the present invention and do not limit the scope of the invention.

A method for producing non-oriented high silicon steel by a cold continuous rolling method comprises the following chemical components: c is less than or equal to 0.0027 percent, and Si: 1.70% -3.35%, Als: 0.20-1.0%, Mn: 0.20-0.8%, O: 0.0045-0.0065%, P is less than or equal to 0.012%, S is less than or equal to 0.0020%, N is less than or equal to 0.0020%, Ti is less than or equal to 0.0020%, V is less than or equal to 0.0020%, Nb is less than or equal to 0.0020%, and B content satisfies: [B] -N + 1/2O, Sn/Sb: 0.04-0.12 percent of Fe and the balance of inevitable residual elements; the process route is as follows: the method comprises the following steps of molten iron desulphurization, converter smelting, RH refining, continuous casting, hot rolling, normalizing, acid washing, cold rolling, continuous furnace annealing, coating, performance inspection and packaging, and specifically comprises the following steps:

1) after RH vacuum decarburization treatment, aluminum deoxidation and partial aluminum alloying are firstly added according to the amount of the aluminum alloy of 1/3-1/2; then alloying the whole silicon steel, adding boron, supplementing the rest aluminum alloy, and adding gold;

2) after alloying, the net circulation of the large-tank molten steel is more than 3 times or more than 5 minutes; the standing time of the molten steel after the molten steel is smelted and before the continuous casting is started is more than twenty minutes; controlling the degree of superheat to be 5-15 ℃; electromagnetic stirring is adopted, and the isometric crystal proportion is controlled to be more than 45%;

3) hot rolling, wherein the charging temperature of the plate blank is more than 750 ℃, and the enrichment and segregation of tin among coarse cast structures are inhibited;

4) the slab temperature of a soaking section of a hot-rolled slab heating furnace is 1000-1150 ℃, the finishing temperature is controlled at 830-930 ℃, and the coiling temperature is 650-750 ℃;

5) the normalizing temperature is 850-950 ℃, slow cooling is carried out at 750-650 ℃ in the cooling process, the cooling speed is controlled to be less than 100 ℃/min, and the grain size is controlled to be 90-110 mu m through the control of the process speed of the soaking section;

6) carrying out acid pickling and finishing, then carrying out cold continuous rolling, preheating a steel strip to 50-150 ℃ before cold rolling, and rolling the steel strip to the thickness of a finished product by controlling the final reduction rate to be below 10%;

7) setting the temperature of a heating section of the continuous annealing furnace to 950-1150 ℃, setting the temperature of a soaking section to 900-1050 ℃, protecting the continuous annealing furnace in a full nitrogen dry atmosphere, and controlling the grain size to be 120-170 mu m and the content of precipitates with the diameter of more than 70nm to be 30-45%; in the cooling process, slowly cooling at the temperature of 800-650 ℃, and controlling the cooling speed to be less than 10 ℃/S.

Example 1

The cold continuous rolling process of producing non-oriented high silicon steel includes the following chemical components: 0.0025%, Si: 2.61%, Als: 0.48%, Mn: 0.28%, O: 0.0056%, P: 0.010%, S: 0.0012%, N: 0.0017%, Ti: 0.0020%, V: 0.0015%, Nb: 0.0013%, B: 0.0045%, Sn: 0.065%, and the balance of Fe and inevitable residual elements; the process route is as follows: the method comprises the following steps of molten iron desulphurization, converter smelting, RH refining, continuous casting, hot rolling, normalizing, acid washing, cold rolling, continuous furnace annealing, coating, performance inspection and packaging, and specifically comprises the following steps:

1) after RH vacuum decarburization treatment, aluminum deoxidation and partial aluminum alloying are carried out, and 1/3 adding amount of aluminum alloy is measured and calculated; then alloying the whole silicon steel, adding boron, supplementing the rest aluminum alloy, and adding tin;

2) after alloying, the large-tank molten steel is circulated for 6 minutes; standing for 22 minutes before casting; controlling the degree of superheat to be 12 ℃; electromagnetic stirring is adopted, and the isometric crystal proportion is controlled to be 50%;

3) hot rolling, wherein the charging temperature of the plate blank is 760 ℃, the temperature of the plate blank at a soaking section is 1080 ℃, the finish rolling temperature is controlled at 870 ℃, and the coiling temperature is 720 ℃;

4) the normalizing temperature of the hot rolled plate is 910 ℃, the cooling speed is controlled to be less than 85 ℃/min at 750-650 ℃ in the cooling process, the process speed of the soaking section is 37m/min, and the grain size is about 95 mu m;

5) preheating the steel strip after pickling before cold rolling, and controlling the final reduction rate to be 6% until the thickness of a finished product is 0.50 mm;

6) setting the temperature of a rapid heating section of the continuous annealing furnace to be 980 ℃, the temperature of a soaking section to be 930 ℃, protecting the continuous annealing furnace in a full nitrogen dry atmosphere, wherein the process speed is 100m/min, the grain size is 135 mu m, and the content of precipitates with the diameter of more than 70nm accounts for 32 percent; (ii) a In the cooling process, slowly cooling at the temperature of 800-650 ℃, and controlling the cooling speed to be less than 8 ℃/S; the product coating, performance detection, roll separation and packaging are the same as the conventional production process.

Example 2

The cold continuous rolling process of producing non-oriented high silicon steel includes the following chemical components: 0.0022%, Si: 2.88%, Als: 0.55%, Mn: 0.31%, O: 0.0060%, P: 0.011%, S: 0.0017%, N: 0.0019%, Ti: 0.0018%, V: 0.0014%, Nb: 0.0015%, B: 0.0049%, Sn: 0.105%, the balance being Fe and unavoidable residual elements; the process route is as follows: the method comprises the following steps of molten iron desulphurization, converter smelting, RH refining, continuous casting, hot rolling, normalizing, acid washing, cold rolling, continuous furnace annealing, coating, performance inspection and packaging, and specifically comprises the following steps:

after RH vacuum decarburization treatment, aluminum deoxidation and partial aluminum alloying are carried out, and 1/3 adding amount of aluminum alloy is measured and calculated; then alloying the whole silicon steel, adding boron, supplementing the rest aluminum alloy, finely adjusting other components, and adding tin alloying;

after alloying, the large-tank molten steel is completely circulated for 4 times; standing for 25 minutes before casting; controlling the degree of superheat to be 10 ℃; electromagnetic stirring is adopted, and the isometric crystal proportion is controlled to be 45%;

hot rolling, wherein the charging temperature of a slab is 780 ℃, the temperature of the slab at a soaking section is 1060 ℃, the finishing temperature is controlled at 850 ℃ and the coiling temperature is 700 ℃;

the normalizing temperature of the hot rolled plate is 920 ℃, the cooling speed is controlled to be less than 85 ℃/min at 750-650 ℃ in the cooling process, the process speed is 35m/min through a soaking section, and the grain size is about 105 mu m;

preheating the steel strip after pickling before cold rolling to 85 ℃, and controlling the final reduction rate to be 5% to roll the steel strip to the thickness of 0.50mm of a finished product;

setting the temperature of a rapid heating section of the continuous annealing furnace to be 1000 ℃, setting the temperature of a soaking section to be 950 ℃, protecting the continuous annealing furnace in a full nitrogen dry atmosphere, wherein the process speed is 100m/min, the grain size is 145 mu m, and the content of precipitates with the diameter of more than 70nm accounts for 35 percent; in the cooling process, slowly cooling at the temperature of 800-650 ℃, and controlling the cooling speed to be less than 8 ℃/S; the product coating, performance detection, roll separation and packaging are the same as the conventional production process.

Comparative example 1

The chemical composition C of the steel grade: 0.0030%, Si: 2.58%, Als: 0.63%, Mn: 0.22%, P: 0.0080%, S: 0.0022%, N: 0.0021%, Ti: 0.0018%, V: 0.0016%, Nb: 0.0011% and the balance of Fe and inevitable residual elements;

after the RH vacuum decarburization treatment, aluminum deoxidation and aluminum alloying silicon steel alloying are carried out, and after alloying, the net circulation of large-tank molten steel is more than 4 minutes; standing for 12 minutes before casting; controlling the degree of superheat to be 20 ℃; electromagnetic stirring is adopted, and the isometric crystal proportion is controlled to be 35%;

hot rolling, wherein the charging temperature of a plate blank is 510 ℃, the temperature of the plate blank at a soaking section is 1120 ℃, the finishing temperature is controlled at 850 ℃ and the coiling temperature is 680 ℃;

the normalizing temperature of the hot rolled plate is 940 ℃, the process speed of the soaking section is 37m/min, and the grain size is about 145 mu m; preheating the steel strip to 65 ℃ after acid washing before cold rolling, and rolling to the thickness of 0.50mm of a finished product;

the temperature of a rapid heating section of the continuous annealing furnace is set to 1130 ℃, the temperature of a soaking section is set to 940 ℃, the hydrogen-nitrogen mixed atmosphere is protected (the hydrogen content is 20%), the process speed is 100m/min, and the grain size is 140 mu m; conventional cooling; the product coating, performance detection, roll separation and packaging are the same as the conventional production process.

Comparative example 2

The chemical composition C of the steel grade: 0.0030%, Si: 2.95%, Als: 0.68%, Mn: 0.34%, P: 0.0095%, S: 0.0025%, N: 0.0018%, Ti: 0.0023%, V: 0.0020%, Nb: 0.0015%, the balance of Fe and inevitable residual elements;

after RH vacuum decarburization treatment, aluminum deoxidation and alloying of aluminum alloyed silicon steel, and fine adjustment of other components; after alloying, the large-tank molten steel is circulated for 5 minutes; standing for 14 minutes before casting; controlling the degree of superheat to be 20 ℃; electromagnetic stirring is adopted, and the isometric crystal proportion is controlled to be 40%;

hot rolling, wherein the charging temperature of the plate blank is 480 ℃, the temperature of the plate blank at a soaking section is 1140 ℃, the finishing temperature is controlled at 850 ℃ and the coiling temperature is 690 ℃;

the normalizing temperature of the hot rolled plate is 930 ℃, the process speed of the soaking section is 37m/min, and the grain size is about 145 mu m; preheating the steel strip after pickling and before cold rolling to 75 ℃, and rolling to the thickness of 0.50mm of a finished product;

the temperature of a rapid heating section of the continuous annealing furnace is set to 1150 ℃, the temperature of a soaking section is set to 950 ℃, the hydrogen-nitrogen mixed atmosphere is protected (the hydrogen content is 20%), the process speed is 95m/min, and the grain size is 155 mu m; conventional cooling; the product coating, performance detection, roll separation and packaging are the same as the conventional production process.