CN112301192B - Vertical annealing process of low-carbon-content cold-rolled non-oriented silicon steel galvanizing unit - Google Patents
Vertical annealing process of low-carbon-content cold-rolled non-oriented silicon steel galvanizing unit Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/26—Methods of annealing
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
- C21D9/54—Furnaces for treating strips or wire
- C21D9/56—Continuous furnaces for strip or wire
- C21D9/561—Continuous furnaces for strip or wire with a controlled atmosphere or vacuum
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
- C21D9/54—Furnaces for treating strips or wire
- C21D9/56—Continuous furnaces for strip or wire
- C21D9/573—Continuous furnaces for strip or wire with cooling
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Abstract
The invention provides a vertical annealing process of a low-carbon cold-rolled non-oriented silicon steel galvanizing unit, which specifically comprises the following steps: the thickness of the strip steel is 0.5 mm; controlling the running speed of the strip steel to be 60-65 mpm; the tension in the vertical annealing furnace is 3-5N/mm 2 (ii) a The furnace temperature of each section is controlled as follows: the preheating section is 200-300 ℃, the heating section is 850-920 ℃, the soaking section is 850-920 ℃, the slow cooling section is 500-600 ℃, the fast cooling section is 200-250 ℃, and the equalizing section is 150-200 ℃; controlling the furnace pressure to be 40-45 Pa; the charging amount of the protective gas is controlled as follows: nitrogen gas 2000m 3 H, hydrogen 150m 3 H; controlling the concentration of hydrogen in the furnace to be 5%; the oxygen content in the furnace is controlled to be 20-30 ppm; the dew point in the furnace is controlled to be-50 to-55 ℃. After the annealing process, the low-temperature environment-friendly insulating coating is coated by a four-roller coating machine, and the coating is dried and cured by a vertical drying furnace, so that the performance of the finished product of each brand can meet the enterprise standard. The process of the invention can not only ensure the flatness of the steel strip and ensure the magnetic property, the magnetic aging and the like of the steel strip to meet the technical requirements, but also improve the product percent of pass, reduce waste products and ensure the smooth production.
Description
Technical Field
The invention belongs to an annealing technology, and particularly relates to a process for annealing low-carbon-content cold-rolled non-oriented silicon steel by a galvanizing unit vertical annealing furnace.
Background
The content of C in the cold-rolled non-oriented silicon steel finished product is required to be less than or equal to 0.003 percent, because carbon is an extremely harmful element and forms a gap solid solution with iron, the crystal lattice is seriously distorted to cause great internal stress, so that the magnetism is reduced, the iron loss value is increased, and the serious magnetic aging is generated.
Therefore, the content of C in the hot-rolled coil which is used as the raw material of the non-oriented silicon steel is required to be less than or equal to 0.005 percent conventionally, so as to ensure that the content of C is reduced to be less than or equal to 0.003 percent in the continuous decarburization annealing process of a horizontal unit after the cold rolling of the non-oriented silicon steel is carried out, and thus the performance of the finished cold-rolled non-oriented silicon steel is ensured.
With the rapid development of smelting technology, most of the existing large and medium-sized steel enterprise non-oriented silicon steel smelting processes can directly reduce the C content of a raw material coil to be below 0.003 percent, and after cold rolling, the non-oriented silicon steel can be used in a horizontal unit continuous decarburization annealing process without a decarburization function, so that recrystallization annealing can be directly completed.
At present, non-oriented silicon steel is produced at home and abroad on a horizontal unit, and an annealing furnace is horizontal and is provided with a special insulating coating machine and a horizontal drying furnace. In addition, the production technology of the non-oriented silicon steel is complex and difficult, the newly-built non-oriented silicon steel project has large investment, long period and long debugging period, and certain investment risk exists.
Disclosure of Invention
The invention aims to provide a vertical annealing process of a low-carbon cold-rolled non-oriented silicon steel galvanizing unit, which is used for realizing the purpose of producing cold-rolled non-oriented silicon steel products in the vertical galvanizing unit by rolling through a pickling and rolling mill combined unit under the condition that the content of C in a hot-rolled coil of a cold-rolled raw material is less than or equal to 0.003 percent. When the invention is used for producing non-oriented silicon steel products, the compatible function of the vertical galvanizing unit is fully exerted, the investment is saved, the risk is reduced, the requirement of developing and producing cold-rolled non-oriented silicon steel is met, and the invention creates a successful precedent in domestic and foreign industries.
In order to achieve the purpose, the invention adopts the technical scheme that:
a vertical annealing process of a low-carbon cold-rolled non-oriented silicon steel galvanizing unit adopts the vertical galvanizing unit to anneal the low-carbon cold-rolled non-oriented silicon steel, and specifically comprises the following steps:
(1) the thickness of the strip steel is 0.5 mm;
(2) controlling the running speed of the strip steel to be 60-65 mpm;
(3) controlling the internal tension of the vertical annealing furnace;
(4) the furnace temperature of each section is controlled as follows: the preheating section is 200-300 ℃, the heating section is 850-920 ℃, the soaking section is 850-920 ℃, the slow cooling section is 500-600 ℃, the fast cooling section is 200-250 ℃, and the equalizing section is 150-200 ℃;
(5) controlling the furnace pressure to be 40-45 Pa;
(6) the charging amount of the protective gas is controlled as follows: nitrogen gas 2000m 3 H, hydrogen 150m 3 /h；
(7) The concentration of hydrogen in the furnace is controlled to be 5 percent;
(8) the oxygen content in the furnace is controlled to be 20-30 ppm;
(9) the dew point in the furnace is controlled to be-50 to-55 ℃.
Further, the tension control in the vertical annealing furnace is 3-5N/mm 2 。
The process design reason of the invention is as follows:
the steel coil is rapidly heated to an alpha-phase region under the condition of hydrogen and nitrogen mixed gas (the content of hydrogen in the furnace is 5 vol%) for recrystallization annealing. The annealing temperature, the annealing time and the dew point in the furnace can directly influence the size of crystal grains, and the atmosphere contains a certain amount of hydrogen to ensure the reducibility in the furnace and ensure the brightness of the strip steel. The lower the annealing temperature is, the smaller the average grain size after annealing is, the larger the iron loss is, and the higher the magnetic induction intensity is; the higher the annealing temperature, the larger the average grain size after annealing, the smaller the iron loss, and the larger the magnetic induction.
When the annealing speed is properly low, the average grain size after annealing is small and increased, the magnetic performance can be improved in a small range, but energy is wasted due to too low speed, and the cost is increased.
The control of the tension in the vertical annealing furnace can ensure good plate shape and also ensure excellent magnetic performance. The strip steel in the furnace can be deviated due to too small tension, and even the furnace can be shut down; the excessive tension can cause the iron loss to rise, the magnetic induction to reduce and even the belt breakage accident in the furnace.
Compared with the prior art, the invention has the beneficial effects that: the vertical annealing process is simple and reasonable, and convenient to operate, when the vertical galvanizing unit is adopted to produce the non-oriented silicon steel coil with low carbon content and carbon content less than or equal to 0.003 percent, after the annealing process, the low-temperature environment-friendly insulating coating is coated by the four-roller coating machine, and the drying and curing are carried out in the vertical drying furnace, so that the performances of middle and low-grade finished products can meet the enterprise standards. The process provided by the invention can ensure that the steel strip is flat, the magnetic property, the magnetic aging and the like of the steel strip meet the technical requirements, the product percent of pass can be improved, waste products are reduced, and the smooth production is ensured.
Drawings
FIG. 1 is a schematic view of a vertical galvanizing unit according to the invention;
in the figure: 1. the method comprises the following steps of (1) preheating section of the vertical annealing furnace, (2) heating section of the vertical annealing furnace, (3) soaking section of the vertical annealing furnace, (4) slow cooling section of the vertical annealing furnace, (5) fast cooling section of the vertical annealing furnace, (6) balancing section of the vertical annealing furnace, (7) coating machine, and (8) drying furnace.
Detailed Description
The technical solutions and effects of the present invention will be further described with reference to the drawings and specific embodiments, but the scope of the present invention is not limited thereto.
The vertical annealing process of the low-carbon cold-rolled non-oriented silicon steel is completed in a vertical galvanizing unit, and the specific flow is shown in figure 1. The content of C is less than or equal to 0.003 percent, a cold-rolled steel coil with the thickness of 0.5mm sequentially passes through a preheating section 1 of a vertical annealing furnace, a heating section 2 of the vertical annealing furnace, a soaking section 3 of the vertical annealing furnace, a slow cooling section 4 of the vertical annealing furnace, a fast cooling section 5 of the vertical annealing furnace, a balancing section 6 of the vertical annealing furnace, a coating machine 7 and a drying furnace 8, and after recrystallization annealing, insulating layer coating and coating drying and solidification, the magnetic performance meets the enterprise standard. The vertical annealing process and the finished product performance of the embodiment of the invention are shown in the table 1, and the conventional horizontal annealing process and the finished product performance are shown in the table 2.
Table 1 vertical annealing process and finished product performance of embodiments of the invention
| Examples | 1 | 2 |
| Steel grade brand | 50W800 | 50W470 |
| Strip steel specification | 0.5×1200mm | 0.5×1200mm |
| C content before annealing | 29ppm | 28ppm |
| Speed of the machine | 60mpm | 65mpm |
| Tension in furnace | 5N/mm 2 | 4N/mm 2 |
| Preheating section furnace temperature | 200～250℃ | 250～300℃ |
| Furnace temperature of heating section | 850～890℃ | 890～920℃ |
| Furnace temperature of soaking zone | 850～890℃ | 890～920℃ |
| Furnace temperature of slow cooling section | 500～550℃ | 550～600℃ |
| Furnace temperature of rapid cooling section | 230～250℃ | 200～230℃ |
| Furnace temperature of equalizing section | 150～180℃ | 180～200℃ |
| Furnace pressure | 40～42Pa | 42～45Pa |
| Protective atmosphere in the furnace | Nitrogen and hydrogen | Nitrogen and hydrogen |
| Amount of nitrogen charged into furnace | 2000m 3 /h | 2000m 3 /h |
| Amount of hydrogen charged into furnace | 150m 3 /h | 150m 3 /h |
| Hydrogen content in furnace | 5％ | 5％ |
| Oxygen content in the furnace | 25～30ppm | 20～25ppm |
| Dew point in furnace | -50～-52℃ | -52～-55℃ |
| Iron loss value of finished product | P1.5 is 4.5W/kg | P1.5 is 4.0W/kg |
| Magnetic induction value of finished product | B5000 is 1.70T | B5000 is 1.64T |
TABLE 2 conventional horizontal annealing Process and finished product Properties
| Examples | 1 | 2 |
| Steel grade brand | 50W800 | 50W470 |
| Strip steel specification | 0.5×1200mm | 0.5×1200mm |
| C content before annealing | 29ppm | 28ppm |
| Speed of the machine | 90—110mpm | 90—110mpm |
| Tension in furnace | 3N/mm 2 | 3N/mm 2 |
| Preheating section furnace temperature | 800～900℃ | 850～950℃ |
| Non-oxidation heating section furnace temperature | 1000～1050℃ | 1050～1100℃ |
| Furnace temperature of heating section of radiant tube | 860～910℃ | 910～950℃ |
| Furnace temperature of soaking zone | 860～910℃ | 910～950℃ |
| Furnace temperature of rapid cooling section | 200～350℃ | 220～380℃ |
| Final cooling zone furnace temperature | 100～150℃ | 100～150℃ |
| Furnace pressure | 10～15Pa | 10～15Pa |
| Protective atmosphere in the furnace | Nitrogen and hydrogen | Nitrogen and hydrogen |
| Hydrogen content in furnace | 5％ | 5％ |
| Oxygen content in the furnace | 10～20ppm | 10～20ppm |
| Dew point in furnace | -20～-30℃ | -20～-30℃ |
| Iron loss value of finished product | P1.5 is 4.6W/kg | P1.5 is 4.1W/kg |
| Magnetic induction value of finished product | B5000 is 1.70T | B5000 is 1.64T |
The vertical annealing process is simple and reasonable, and convenient to operate, when the vertical galvanizing unit is adopted to produce the non-oriented silicon steel coil with low carbon content and carbon content less than or equal to 0.003 percent, after the annealing process, the low-temperature environment-friendly insulating coating is coated by the four-roller coating machine, and the non-oriented silicon steel coil is dried and cured by the vertical drying furnace, so that the performance of the finished product of each brand can meet the enterprise standard. The process of the invention can not only ensure the flatness of the steel strip and ensure the magnetic property, the magnetic aging and the like of the steel strip to meet the technical requirements, but also improve the product percent of pass, reduce waste products and ensure the smooth production.
Finally, it should be noted that the above-mentioned description is only for illustrating the technical solution of the present invention and not for limiting, and other modifications or equivalent substitutions made by the technical solution of the present invention by those skilled in the art should be covered in the scope of the claims of the present invention as long as they do not depart from the spirit of the technical solution of the present invention.
Claims (1)
1. A vertical annealing process of a low-carbon cold-rolled non-oriented silicon steel galvanizing unit is characterized in that the grade of steel is 50W800 or 50W470, the process is that under the condition that the content of C in a hot-rolled coil of a cold-rolled raw material is less than or equal to 0.003 percent, the cold-rolled non-oriented silicon steel with low carbon content is annealed by adopting the vertical galvanizing unit through rolling of an acid pickling rolling mill combined unit, and the process specifically comprises the following steps:
(1) the thickness of the strip steel is 0.5 mm;
(2) controlling the running speed of the strip steel to be 60-65 mpm;
(3) controlling the tension in the vertical annealing furnace;
(4) the furnace temperature of each section is controlled as follows: the preheating section is 200-300 ℃, the heating section is 850-920 ℃, the soaking section is 850-920 ℃, the slow cooling section is 500-600 ℃, the fast cooling section is 200-250 ℃, and the equalizing section is 150-200 ℃;
(5) controlling the furnace pressure to be 40-45 Pa;
(6) the charging amount of the protective gas is controlled as follows: nitrogen gas 2000m 3 H, hydrogen 150m 3 /h；
(7) Controlling the concentration of hydrogen in the furnace to be 5%;
(8) the oxygen content in the furnace is controlled to be 20-30 ppm;
(9) controlling the dew point in the furnace to be-50 to-55 ℃;
the tension control in the vertical annealing furnace is 4-5N/mm 2 。
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01234524A (en) * | 1988-03-11 | 1989-09-19 | Nkk Corp | Continuous annealing method for non-oriented silicon steel sheet |
| WO2013095006A1 (en) * | 2011-12-20 | 2013-06-27 | 주식회사 포스코 | High silicon steel sheet having excellent productivity and magnetic properties and method for manufacturing same |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPS61119620A (en) * | 1984-11-14 | 1986-06-06 | Kawasaki Steel Corp | Annealing method of silicon steel strip by vertical continuous annealing furnace |
| JP4244393B2 (en) * | 1998-02-13 | 2009-03-25 | Ｊｆｅスチール株式会社 | Method for producing non-oriented electrical steel sheet having excellent surface properties and iron loss characteristics, and non-oriented electrical steel sheet having excellent surface properties and iron loss characteristics |
| CN103882192B (en) * | 2012-12-21 | 2015-11-18 | 鞍钢股份有限公司 | A kind of method for annealing of high interlamination resistance cold rolling non-oriented electrical steel |
| CN103882193B (en) * | 2012-12-21 | 2016-05-04 | 鞍钢股份有限公司 | A kind of cold rolling non-oriented electrical steel method for annealing of outer oxide |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01234524A (en) * | 1988-03-11 | 1989-09-19 | Nkk Corp | Continuous annealing method for non-oriented silicon steel sheet |
| WO2013095006A1 (en) * | 2011-12-20 | 2013-06-27 | 주식회사 포스코 | High silicon steel sheet having excellent productivity and magnetic properties and method for manufacturing same |
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