CN114250420A - Production method of cover type intermediate annealing high-grade non-oriented silicon steel 50BW350 - Google Patents
Production method of cover type intermediate annealing high-grade non-oriented silicon steel 50BW350 Download PDFInfo
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- 238000000137 annealing Methods 0.000 title claims abstract description 140
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- 229910000976 Electrical steel Inorganic materials 0.000 title claims abstract description 27
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- 238000005098 hot rolling Methods 0.000 claims abstract description 44
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- 230000000694 effects Effects 0.000 claims description 15
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- 238000005554 pickling Methods 0.000 claims description 9
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Abstract
The invention relates to a production method of hood-type intermediate annealing high-grade non-oriented silicon steel 50BW350, which comprises the steps of molten steel chemical composition design, hot rolling process, cold rolling process, annealing process and the like; the molten steel comprises the chemical components of less than or equal to 0.004 percent of C, 1.80 to 2.1 percent of Si, 0.70 to 0.90 percent of Mn, 0.30 to 0.45 percent of Als, less than or equal to 0.015 percent of P, less than or equal to 0.0030 percent of S, less than or equal to 0.0020 percent of O, less than or equal to 0.0025 percent of N, 0.06 to 0.12 percent of Sb0, and the balance of Fe. According to the invention, through special chemical design, Sb element is added, the electromagnetic performance is improved by optimizing the structural structure of the product, the Si content is properly reduced, the Mn element content is improved, the influence of hot rolling of coarse fiber structure is eliminated by a secondary cold rolling method, the high-grade non-oriented silicon steel product without surface corrugation defects is obtained, compared with the traditional high-grade production method, the cost is lower, and the electromagnetic performance of the produced silicon steel is excellent.
Description
Technical Field
The invention relates to the technical field of agricultural motors, in particular to a production method of hood-type intermediate annealing high-grade non-oriented silicon steel 50BW 350.
Background
The 50BW350 high-grade non-oriented silicon steel product is mainly applied to air conditioners and refrigerator variable frequency compressors, compared with the common non-oriented silicon steel, the high-grade non-oriented silicon steel has the characteristic of low iron loss, can save a large amount of electric energy, meets the national requirements of energy conservation and emission reduction, has higher added value of products, has better market application prospect in the future, but has large production difficulty, and the conventional production method needs electromagnetic stirring and normalizing annealing equipment.
At present, the conventional 50BW350 high-grade non-oriented silicon steel needs to adopt steelmaking electromagnetic stirring and normalizing annealing of a hot rolling raw material coil, the chemical components adopt a high-silicon-content design, the Si content is usually more than or equal to 3%, the columnar crystal structure in a continuous casting billet needs to be crushed through the electromagnetic stirring, the columnar crystal structure is prevented from forming a hot rolling fiber structure in the hot rolling process, and the corrugated defect is generated on the surface of a steel plate in the subsequent cold rolling process to influence the surface quality and the electromagnetic performance. The hot rolled steel coil needs to be treated by normalizing annealing to promote the recrystallization of crystal grains, improve the structure performance and improve the surface quality and the electromagnetic performance of a finished product.
Disclosure of Invention
Aiming at the problems, the invention aims to provide a production method of hood-type intermediate annealing high-grade non-oriented silicon steel 50BW350, which is characterized in that the content of Si element in the non-oriented silicon steel is properly reduced by adding Sb element, the surface corrugation defect caused by high content of Si is eliminated by combining hot rolling process control and hood-type annealing process control, and the electromagnetic performance of a 50BW350 product is ensured to meet the standard requirement.
The technical scheme adopted by the invention is as follows:
the invention provides a production method of cover type intermediate annealing high-grade non-oriented silicon steel 50BW350, wherein the non-oriented silicon steel 50BW350 comprises the following chemical components in percentage by mass: c is less than or equal to 0.004%, Si: 1.80-2.1%, Mn: 0.70-0.90%, Als: 0.30-0.45%, P is less than or equal to 0.015%, S is less than or equal to 0.0030%, O is less than or equal to 0.0020%, N is less than or equal to 0.0025%, Sb: 0.06-0.12%, and the balance of Fe and inevitable impurities;
the production method comprises the following steps:
s1, obtaining a plate blank with required chemical components through steel-making production;
s2, carrying out hot rolling on the plate blank; hot rolling production is carried out on a 1700mm continuous rolling production line; wherein the thickness of the cast strip is 230mm, the thickness of the hot-rolled coil is 2.55mm, the slab adopts a low-temperature heating process of not more than 1150 ℃, the temperature requirement of the strip steel in finish rolling is not lower than 950 ℃, the target temperature of the finish rolling is 850-890 ℃, and the coiling temperature is controlled at 680-720 ℃;
s3, carrying out cold rolling after pickling on the plate blank obtained in the S2; the cold rolling process sequentially comprises the following steps: hot rolling a plate, primary cold rolling, cover type annealing process, secondary cold rolling and continuous annealing process.
Further, in the step S3, a hot rolled plate is rolled by a secondary cold rolling method, the reduction of the primary cold rolling is 10%, and then the cover annealing is performed to improve the structure property of the hot rolled material; and performing secondary cold rolling to the thickness of a finished product of 0.5mm, and then performing high-temperature continuous annealing to obtain a grain structure and a texture which are favorable for electromagnetic performance.
Furthermore, in the cover annealing process, in order to ensure the full recrystallization and the grain boundary segregation effect of the Sb element in the continuous annealing process, the cover annealing heat preservation temperature is not less than 730 ℃, and the heat preservation time is more than 30 hours.
Further, in the continuous annealing process, the temperature of the NOF in the preheating section of the heating furnace is 1000-1050 ℃; the temperature of the RTF section is 910-930 ℃; the temperature of the SF section is 920-.
Compared with the prior art, the invention has the following beneficial effects:
compared with the conventional method for producing the high-grade 50BW350 product, the invention does not need a steel-making electromagnetic stirring device and a normalizing annealing device of a hot rolled steel coil, reduces the equipment investment and the process cost, only needs to control the content of the inclusion elements of the molten steel in the steel-making production process, adopts a casting blank low-temperature heating technology in the heating process, reduces the precipitation of MnS and AlN inclusion in the casting blank, ensures the segregation of Sb element at the grain boundary and the full recrystallization growth of crystal grains in the final annealing process, formulates a reasonable hot rolling process and a cold rolling annealing process, adopts hot rolling high-temperature final rolling and coiling, cold rolling high-temperature annealing, fully exerts the grain boundary segregation function of the Sb element, and increases the {110} {100} texture component.
Drawings
FIG. 1 is a flow chart of a production method of a bell-type interannealed high-grade non-oriented silicon steel 50BW350 provided by the invention;
FIG. 2 is a schematic view of the microstructure of high grade non-oriented silicon steel produced by the method of the present invention;
FIG. 3 is a schematic view of the surface quality of 50BW350 non-oriented silicon steel produced by the method of the present invention;
fig. 4 is a schematic diagram of corrugation defects on the surface of 50BW350 non-oriented silicon steel produced by the prior art.
Detailed Description
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
The invention provides a production method of cover type intermediate annealing high-grade non-oriented silicon steel 50BW350, wherein the non-oriented silicon steel 50BW350 comprises the following chemical components in percentage by weight: c is less than or equal to 0.004%, Si: 1.80-2.1%, Mn: 0.70-0.90%, Als: 0.30-0.45%, P is less than or equal to 0.015%, S is less than or equal to 0.0030%, O is less than or equal to 0.0020%, N is less than or equal to 0.0025%, Sb: 0.06-0.12%, and the balance of Fe and inevitable impurities.
As shown in fig. 1, the production method comprises the steps of:
s1, making steel to obtain a plate blank with required chemical components; specifically, a plate blank is obtained after continuous casting through smelting chemical component control and inclusion control of molten steel;
s2, carrying out hot rolling on the slab to obtain a required hot rolling raw material coil;
specifically, hot rolling production is carried out on a 1700mm continuous rolling production line, the thickness of a cast slab is 230mm, the thickness of a hot rolled coil is 2.55mm, a low-temperature heating process (less than or equal to 1150 ℃) is adopted for a plate blank, the precision rolling temperature of the strip steel is not lower than 950 ℃, the target temperature of the finish rolling is 850-890 ℃, and the coiling temperature is controlled at 680-720 ℃; obtaining a required hot-rolled raw steel coil;
s3, pickling the hot-rolled raw material coil to obtain a pickling raw material coil required by cold rolling;
in order to ensure the surface quality of the steel coil after pickling, a reasonable pickling process is formulated, and the acid liquor concentration and the pickling speed are as follows: acid liquor concentration: HCL content is 80-110 g/L, and strip steel withdrawal and straightening elongation is as follows: 1.4%, pickling speed: 90 to 110 m/min.
Carrying out first cold rolling on the pickling raw material coil, and reducing by 10% to obtain an intermediate annealing raw material coil;
performing cover annealing on the raw material coil subjected to the primary cold rolling: in order to ensure the full recrystallization and the grain boundary segregation effect of the Sb element in the continuous annealing process, the annealing heat preservation temperature is more than or equal to 730 ℃, and the heat preservation time is more than 30 hours;
carrying out secondary cold rolling on the intermediate annealing coil until the thickness of the intermediate annealing coil is 0.5 mm;
and (3) final continuous annealing: continuously annealing the steel coil, wherein the temperature of the NOF in the preheating section of the heating furnace is 1000-1050 ℃ for promoting the growth of crystal grains; the RTF temperature of the radiation heating section is 910-930 ℃; the temperature of the soaking section SF furnace is 920 ℃ and 940 ℃ for annealing, and the higher annealing temperature is favorable for the growth of crystal grains and the formation of texture.
The following are exemplified:
example one:
s1, steel-making components: C. the contents of Si, Mn, P, S, Als, Sb, O and N are respectively as follows: 0.003%, 1.85%, 0.85%, 0.013%, 0.0025%, 0.41%, 0.08%, 0.0018%, 0.0021%, the balance being Fe and unavoidable inclusions; controlling smelting chemical components and inclusions of molten steel, and continuously casting to obtain a plate blank;
s2, hot rolling and heating at 1130 ℃; the hot rolling adopts high-temperature final rolling and high-temperature curling, and the final rolling temperature is 880-; the curling temperature is 700-720 ℃;
s3, cold rolling: hot rolled plate → primary cold rolling reduction 10% → cap annealing → secondary cold rolling to 0.5mm → continuous annealing;
cover annealing: in order to ensure the full recrystallization and the grain boundary segregation effect of the Sb element in the continuous annealing process, the annealing heat preservation temperature is more than or equal to 730 ℃, and the heat preservation time is more than 30 hours;
the continuous annealing adopts high-temperature annealing: in order to promote the growth of crystal grains, the temperature of the NOF in the preheating section is 1000-1050 ℃; the temperature of the RTF section is 910-930 ℃; the temperature of the SF section is 920-940 ℃; the higher annealing temperature is beneficial to the growth of crystal grains and the formation of texture;
the thickness of the finished product is 0.5 mm.
Comparative example one:
s1, steel-making components: the chemical composition is the same as that of the first embodiment; controlling smelting chemical components and inclusions of molten steel, and continuously casting to obtain a plate blank;
s2, hot rolling and heating at 1130 ℃; the hot rolling adopts high-temperature final rolling and high-temperature curling, and the final rolling temperature is 880-; the curling temperature is 700-720 ℃;
s3, cold rolling: hot rolled plate → primary cold rolling reduction 10% → cap annealing → secondary cold rolling to 0.5mm → continuous annealing;
cover annealing: in order to ensure the full recrystallization and the grain boundary segregation effect of the Sb element in the continuous annealing process, the annealing heat preservation temperature is more than or equal to 730 ℃, and the heat preservation time is more than 30 hours;
the continuous annealing adopts low-temperature annealing: the temperature of NOF in the preheating section is 1000-1020 ℃; the RTF temperature of the radiation heating section is 880-900 ℃; the temperature of the SF furnace at the soaking section is 860 ℃ and 890 ℃ for annealing;
the thickness of the finished product is 0.5 mm.
Electromagnetic properties are shown in table 1:
TABLE 1 electromagnetic performance index of example 1 and comparative example 1
From the analysis of electromagnetic indexes of example 1 and comparative example 1, in comparative example 1, under the same chemical composition conditions, the same hot rolling process and the same secondary cold rolling and cover annealing process are different only in the final continuous annealing process, high-temperature annealing is adopted in example 1, low-temperature annealing is adopted in comparative example 1, the electromagnetic performance of the material object in comparative example 1 is reduced to a certain extent compared with that in example 1, the iron loss and the magnetic induction are not the same as those in example 1, and the main reason is that the recrystallization of the crystal material is insufficient compared with that in example 1.
Example two:
s1, steel-making components: C. the contents of Si, Mn, P, S, Als, Sb, O and N are respectively as follows: 0.003%, 1.85%, 0.85%, 0.013%, 0.0025%, 0.41%, 0.08%, 0.0018%, 0.0021%, the balance being Fe and unavoidable inclusions; controlling smelting chemical components and inclusions of molten steel, and continuously casting to obtain a plate blank;
s2, hot rolling and heating at 1130 ℃; the hot rolling adopts high-temperature final rolling and high-temperature curling, and the final rolling temperature is 880-; the curling temperature is 700-720 ℃;
s3, cold rolling: hot rolled plate → primary cold rolling reduction 10% → cap annealing → secondary cold rolling to 0.5mm → continuous annealing;
cover annealing: in order to ensure the full recrystallization and the grain boundary segregation effect of the Sb element in the continuous annealing process, the annealing heat preservation temperature is more than or equal to 730 ℃, and the heat preservation time is more than 30 hours;
the continuous annealing adopts high-temperature annealing: the temperature of the NOF in the preheating section is 1000-1050 ℃, and the temperature of the RTF section is 910-930 ℃; the temperature of the SF section is 920-940 ℃;
the thickness of the finished product is 0.5 mm.
Comparative example two:
s1, steel-making components: same as the two chemical compositions of the examples; controlling smelting chemical components and inclusions of molten steel, and continuously casting to obtain a plate blank;
s2, hot rolling and heating at 1130 ℃; the hot rolling adopts high-temperature final rolling and high-temperature curling, and the final rolling temperature is 880-; the curling temperature is 700-720 ℃;
s3, cold rolling: hot rolled plate → one-time cold rolling to 0.5mm → continuous annealing;
the continuous annealing employed the same high temperature annealing process as example two: the temperature of the NOF in the preheating section is 1000-1050 ℃; the temperature of the RTF section is 910-930 ℃; the temperature of the SF section is 920-940 ℃;
the thickness of the finished product is 0.5 mm.
Electromagnetic properties are shown in table 2:
TABLE 2 electromagnetic performance index of example 2 and comparative example 2
From the analysis of the electromagnetic indexes of the example 2 and the comparative example 2, the comparative example 2 does not carry out secondary cold rolling and cover annealing under the same chemical composition condition and the same hot rolling process condition, but the final continuous annealing process is the same, and the electromagnetic performance of the comparative example 2 is greatly reduced compared with that of the example 2, mainly because the hot rolling raw material coil does not carry out secondary cold rolling and cover annealing, the crystal structure of the raw material coil is not improved, and the corrugated defect appears on the surface of the finished product of the comparative example 2.
Example three:
s1, steel-making components: C. the contents of Si, Mn, P, S, Als, Sb, O and N are respectively as follows: 0.003%, 1.85%, 0.85%, 0.013%, 0.0025%, 0.41%, 0.08%, 0.0018%, 0.0021%, the balance being Fe and unavoidable inclusions; controlling smelting chemical components and inclusions of molten steel, and continuously casting to obtain a plate blank;
s2, hot rolling and heating at 1130 ℃; the hot rolling adopts high-temperature final rolling and high-temperature curling, and the final rolling temperature is 880-; the curling temperature is 700-720 ℃;
s3, cold rolling: hot rolled plate → primary cold rolling reduction 10% → cap annealing → secondary cold rolling to 0.5mm → continuous annealing;
cover annealing: in order to ensure the full recrystallization and the grain boundary segregation effect of the Sb element in the continuous annealing process, the annealing heat preservation temperature is more than or equal to 730 ℃, and the heat preservation time is more than 30 hours;
the continuous annealing adopts high-temperature annealing: the temperature of the NOF in the preheating section is 1000-1050 ℃; the temperature of the RTF section is 910-930 ℃; the temperature of the SF section is 920-940 ℃;
the thickness of the finished product is 0.5 mm.
Comparative example three:
s1, steel-making components: the chemical composition is the same as that of the third example; controlling smelting chemical components and inclusions of molten steel, and continuously casting to obtain a plate blank;
s2, hot rolling and heating at 1130 ℃; the hot rolling adopts high-temperature final rolling and high-temperature curling, and the final rolling temperature is 880-; the curling temperature is 700-720 ℃;
s3, cold rolling: hot rolled plate → primary cold rolling reduction 30% → cap annealing → secondary cold rolling to 0.5mm → continuous annealing;
cover annealing: in order to ensure the full recrystallization and the grain boundary segregation effect of the Sb element in the continuous annealing process, the annealing heat preservation temperature is more than or equal to 730 ℃, and the heat preservation time is more than 30 hours;
the continuous annealing adopts low-temperature annealing: the temperature of NOF in the preheating section is 1000-1020 ℃; the RTF temperature of the radiation heating section is 880-900 ℃; annealing at the temperature of 860 ℃ and 890 ℃ in the SF furnace at the soaking section;
the thickness of the finished product is 0.5 mm.
Electromagnetic properties are shown in table 3:
TABLE 3 electromagnetic performance index of example 3 and comparative example 3
From the analysis of the electromagnetic indexes of example 3 and comparative example 3, except for the primary cold rolling reduction, example 3 uses the critical reduction of 10% and comparative example 3 uses the reduction of 30%, the electromagnetic performance index comparative example 3 has high iron loss and low magnetic induction, and the electromagnetic performance index is lower than that of example 3, mainly because the primary reduction is different, and the 10% critical reduction is better than the 30% primary reduction for the electromagnetic performance of the finished product.
Example four:
s1, steel-making components: C. the contents of Si, Mn, P, S, Als, Sb, O and N are respectively as follows: 0.003%, 1.85%, 0.85%, 0.013%, 0.0025%, 0.41%, 0.08%, 0.0018%, 0.0021%, the balance being Fe and unavoidable inclusions; controlling smelting chemical components and inclusions of molten steel, and continuously casting to obtain a plate blank;
s2, hot rolling and heating at 1130 ℃; the hot rolling adopts high-temperature final rolling and high-temperature curling, and the final rolling temperature is 880-; the curling temperature is 700-720 ℃;
s3, cold rolling: hot rolled plate → primary cold rolling reduction 10% → cap annealing → secondary cold rolling to 0.5mm → continuous annealing;
cover annealing: in order to ensure the full recrystallization and the grain boundary segregation effect of the Sb element in the continuous annealing process, the annealing heat preservation temperature is more than or equal to 730 ℃, and the heat preservation time is more than 30 hours;
the continuous annealing adopts high-temperature annealing: the temperature of the NOF in the preheating section is 1000-1050 ℃; the temperature of the RTF section is 910-930 ℃; the temperature of the SF section is 920-940 ℃;
the thickness of the finished product is 0.5 mm.
Comparative example four:
s1, steel-making components: the chemical composition is the same as that of example four; controlling smelting chemical components and inclusions of molten steel, and continuously casting to obtain a plate blank;
s2, hot rolling and heating at 1130 ℃; the hot rolling adopts high-temperature final rolling and high-temperature curling, and the final rolling temperature is 880-; the curling temperature is 700-720 ℃;
s3, cold rolling: hot rolled plate → primary cold rolling reduction 50% → cap annealing → secondary cold rolling to 0.5mm → continuous annealing;
cover annealing: in order to ensure the full recrystallization and the grain boundary segregation effect of the Sb element in the continuous annealing process, the annealing heat preservation temperature is more than or equal to 730 ℃, and the heat preservation time is more than 30 hours;
the continuous annealing adopts low-temperature annealing: the temperature of NOF in the preheating section is 1000-1020 ℃; the RTF temperature of the radiation heating section is 880-900 ℃; annealing at the temperature of 860 ℃ and 890 ℃ in the SF furnace at the soaking section;
the thickness of the finished product is 0.5 mm.
Electromagnetic properties are shown in table 4:
TABLE 4 electromagnetic performance index of example 4 and comparative example 4
From the analysis of the electromagnetic indexes of example 4 and comparative example 4, except for the primary cold rolling reduction, example 4 used a 10% reduction ratio of the critical reduction ratio, and comparative example 4 used a 50% reduction ratio, the electromagnetic performance index comparative example 4 had high iron loss, low magnetic induction, and the electromagnetic performance index was lower than that of example 4, mainly because the 10% reduction ratio of the critical reduction ratio was superior to the 50% reduction ratio of the electromagnetic performance of the finished product due to the difference in the primary reduction ratio.
Example five:
s1, steel-making components: C. the contents of Si, Mn, P, S, Als, Sb, O and N are respectively as follows: 0.003%, 1.85%, 0.85%, 0.013%, 0.0025%, 0.41%, 0.08%, 0.0018%, 0.0021%, the balance being Fe and unavoidable inclusions; controlling smelting chemical components and inclusions of molten steel, and continuously casting to obtain a plate blank;
s2, hot rolling and heating at 1130 ℃; the hot rolling adopts high-temperature final rolling and high-temperature curling, and the final rolling temperature is 880-; the curling temperature is 700-720 ℃;
s3, cold rolling: hot rolled plate → primary cold rolling reduction 10% → cap annealing → secondary cold rolling to 0.5mm → continuous annealing;
cover annealing: in order to ensure the full recrystallization and the grain boundary segregation effect of the Sb element in the continuous annealing process, the annealing heat preservation temperature is more than or equal to 730 ℃, and the heat preservation time is more than 30 hours;
the continuous annealing adopts high-temperature annealing: the temperature of the NOF in the preheating section is 1000-1050 ℃; the temperature of the RTF section is 910-930 ℃; the temperature of the SF section is 920-940 ℃;
the thickness of the finished product is 0.5 mm.
Comparative example five:
s1, steel-making components: C. the contents of Si, Mn, P, S, Als, Sb, O and N are respectively as follows: 0.003%, 1.89%, 0.87%, 0.014%, 0.0024%, 0.039%, 0.03%, 0.0019%, 0.0020%, and the balance of Fe and inevitable impurities; controlling smelting chemical components and inclusions of molten steel, and continuously casting to obtain a plate blank;
s2, hot rolling and heating at 1130 ℃; the hot rolling adopts high-temperature final rolling and high-temperature curling, and the final rolling temperature is 880-; the curling temperature is 700-720 ℃;
s3, cold rolling: hot rolled plate → primary cold rolling reduction 50% → cap annealing → secondary cold rolling to 0.5mm → continuous annealing;
cover annealing: in order to ensure the full recrystallization and the grain boundary segregation effect of the Sb element in the continuous annealing process, the annealing heat preservation temperature is more than or equal to 730 ℃, and the heat preservation time is more than 30 hours;
the continuous annealing adopts low-temperature annealing: the temperature of NOF in the preheating section is 1000-1020 ℃; the RTF temperature of the radiation heating section is 880-900 ℃; annealing at the temperature of 860 ℃ and 890 ℃ in the SF furnace at the soaking section;
the thickness of the finished product is 0.5 mm.
Electromagnetic properties are shown in table 5:
TABLE 5 electromagnetic performance index of example 5 and comparative example 5
From the analysis of the electromagnetic indexes of example 5 and comparative example 5, the chemical compositions of example 5 and comparative example 5 are different, the content of Sb element in example 5 is 0.08%, the content of Sb element in comparative example 5 is 0.03%, the electromagnetic performance index of comparative example 5 has high iron loss and low magnetic induction, and the electromagnetic performance index is lower than that of example 5, mainly because the content of Sb element in comparative example 5 is low, grain boundary segregation is not obvious in example 5, and the texture favorable for the electromagnetic performance is less than that of example 5.
Example six:
s1, steel-making components: C. the contents of Si, Mn, P, S, Als, Sb, O and N are respectively as follows: 0.003%, 1.85%, 0.85%, 0.013%, 0.0025%, 0.41%, 0.08%, 0.0018%, 0.0021%, the balance being Fe and unavoidable inclusions; controlling smelting chemical components and inclusions of molten steel, and continuously casting to obtain a plate blank;
s2, hot rolling and heating at 1130 ℃; the hot rolling adopts high-temperature final rolling and high-temperature curling, and the final rolling temperature is 880-; the curling temperature is 700-720 ℃;
s3, cold rolling: hot rolled plate → primary cold rolling reduction 10% → cap annealing → secondary cold rolling to 0.5mm → continuous annealing;
cover annealing: in order to ensure the full recrystallization and the grain boundary segregation effect of the Sb element in the continuous annealing process, the annealing heat preservation temperature is more than or equal to 730 ℃, and the heat preservation time is more than 30 hours;
the continuous annealing adopts high-temperature annealing: the temperature of the NOF in the preheating section is 1000-1050 ℃; the temperature of the RTF section is 910-930 ℃; the temperature of the SF section is 920-940 ℃;
the thickness of the finished product is 0.5 mm.
Comparative example six:
s1, steel-making components: C. the contents of Si, Mn, P, S, Als, Sb, O and N are respectively as follows: 0.0031%, 1.88%, 0.84%, 0.012%, 0.0022%, 0.40%, 0%, 0.0018%, 0.0019%, and the balance of Fe and inevitable impurities; controlling smelting chemical components and inclusions of molten steel, and continuously casting to obtain a plate blank;
s2, hot rolling and heating at 1130 ℃; the hot rolling adopts high-temperature final rolling and high-temperature curling, and the final rolling temperature is 880-; the curling temperature is 700-720 ℃;
s3, cold rolling: hot rolled plate → primary cold rolling reduction 50% → cap annealing → secondary cold rolling to 0.5mm → continuous annealing;
cover annealing: in order to ensure the full recrystallization and the grain boundary segregation effect of the Sb element in the continuous annealing process, the annealing heat preservation temperature is more than or equal to 730 ℃, and the heat preservation time is more than 30 hours;
the continuous annealing adopts low-temperature annealing: the temperature of NOF in the preheating section is 1000-1020 ℃; the RTF temperature of the radiation heating section is 880-900 ℃; annealing at the temperature of 860 ℃ and 890 ℃ in the SF furnace at the soaking section;
the thickness of the finished product is 0.5 mm.
Electromagnetic properties are shown in table 6:
TABLE 6 electromagnetic performance index of example 6 and comparative example 6
From the analysis of the electromagnetic indexes of the example 6 and the comparative example 6, the chemical components of the example 6 and the comparative example 6 are different, the content of the Sb element in the example 6 is 0.08%, the Sb element is not added in the comparative example 6, the electromagnetic performance index of the comparative example 6 is greatly reduced, the iron loss is high, the magnetic induction is low, the improvement effect of the grain boundary segregation of the Sb element on the electromagnetic performance is obvious, and the electromagnetic performance can not reach the standard requirement without adding the grain boundary segregation element Sb under the conditions of no electromagnetic stirring and no normalizing annealing equipment.
From the above examples and comparative examples, it can be seen that the high-grade non-oriented silicon steel 50BW350 produced by the method of the present invention has low production cost and excellent electromagnetic performance, and compared with the high-grade non-oriented silicon steel 50BW350 produced by the conventional method, the method has the advantages of low equipment investment and production cost reduction of about 50 yuan/ton.
The above-mentioned embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solution of the present invention by those skilled in the art should fall within the protection scope defined by the claims of the present invention without departing from the spirit of the present invention.
Claims (4)
1. A production method of cover type intermediate annealing high-grade non-oriented silicon steel 50BW350 is characterized in that the non-oriented silicon steel 50BW350 comprises the following chemical components in percentage by mass: c is less than or equal to 0.004%, Si: 1.80-2.1%, Mn: 0.70-0.90%, Als: 0.30-0.45%, P is less than or equal to 0.015%, S is less than or equal to 0.0030%, O is less than or equal to 0.0020%, N is less than or equal to 0.0025%, Sb: 0.06-0.12%, and the balance of Fe and inevitable impurities;
the production method comprises the following steps:
s1, obtaining a plate blank with required chemical components through steel-making production;
s2, carrying out hot rolling on the plate blank; hot rolling production is carried out on a 1700mm continuous rolling production line; wherein the thickness of the cast strip is 230mm, the thickness of the hot-rolled coil is 2.55mm, the slab adopts a low-temperature heating process of not more than 1150 ℃, the temperature requirement of the strip steel in finish rolling is not lower than 950 ℃, the target temperature of the finish rolling is 850-890 ℃, and the coiling temperature is controlled at 680-720 ℃;
s3, carrying out cold rolling after pickling on the plate blank obtained in the S2; the cold rolling process sequentially comprises the following steps: hot rolling a plate, primary cold rolling, cover type annealing process, secondary cold rolling and continuous annealing process.
2. The production method of the bell-type intermediate annealing high-grade non-oriented silicon steel 50BW350 as claimed in claim 1, wherein: in the step S3, a hot rolled plate is rolled by a secondary cold rolling method, the reduction of the primary cold rolling is 10%, and then hood annealing is performed to improve the structure performance of the hot rolled material; and performing secondary cold rolling to the thickness of a finished product of 0.5mm, and then performing high-temperature continuous annealing to obtain a grain structure and a texture which are favorable for electromagnetic performance.
3. The production method of the bell-type intermediate annealing high-grade non-oriented silicon steel 50BW350 as claimed in claim 1, wherein: in the cover annealing process, in order to ensure the full recrystallization and the grain boundary segregation effect of the Sb element in the continuous annealing process, the cover annealing heat preservation temperature is more than or equal to 730 ℃, and the heat preservation time is more than 30 hours.
4. The production method of the bell-type intermediate annealing high-grade non-oriented silicon steel 50BW350 as claimed in claim 1, wherein: in the continuous annealing process, the temperature of the NOF in the preheating section of the heating furnace is 1000-1050 ℃; the temperature of the RTF section is 910-930 ℃; the temperature of the SF section is 920-.
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| CN115058573A (en) * | 2022-06-20 | 2022-09-16 | 马鞍山钢铁股份有限公司 | Production method of high-grade non-oriented silicon steel after strip breakage in one-step cold rolling |
| CN116240471A (en) * | 2023-02-21 | 2023-06-09 | 包头钢铁（集团）有限责任公司 | Sb-containing non-oriented silicon steel 50W600 and preparation method thereof |
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| CN114854966A (en) * | 2022-04-12 | 2022-08-05 | 湖南华菱涟钢特种新材料有限公司 | Electrical steel, method for producing same and product |
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