Oriented silicon steel pickling coil, preparation method thereof and oriented silicon steel finished product

Abstract

The invention belongs to the technical field of oriented silicon steel production, and particularly relates to an oriented silicon steel acid pickling coil, a preparation method thereof and an oriented silicon steel finished product. Comprising the following steps: heating a continuous casting sheet billet, carrying out dephosphorization treatment on the heated continuous casting sheet billet, and carrying out hot continuous rolling on the continuous casting sheet billet subjected to dephosphorization treatment to obtain a hot rolled coil; cooling the hot-rolled coil in a protective atmosphere to obtain strip steel, and performing shot blasting treatment on the strip steel; the strip steel subjected to shot blasting treatment is subjected to acid pickling in acid liquor added with an acid pickling accelerant, in the acid pickling process, the acid pickling time of the head of the strip steel is 90-100 s, the acid pickling time of the tail of the strip steel is 110-120 s, and the acid pickling accelerant comprises a complexing agent composed of sulfite and furandione derivatives containing carbon-carbon double bonds. Oxidized iron scale on the surface of the oriented silicon steel pickling coil prepared through the method is thoroughly pickled, the surface of strip steel obtained after decarburization annealing has metallic luster, and a silicon steel finished product prepared through the pickling coil has excellent magnetic performance and coating adhesive force.

Description

Technical Field

[0001] The invention belongs to the technical field of oriented silicon steel production, and in particular relates to an oriented silicon steel pickling coil and a preparation method thereof, and an oriented silicon steel finished product. Background Art

[0002] Oriented silicon steel is an energy-saving soft magnetic alloy material with low iron loss and high magnetic induction. It is widely used in the manufacture of various transformer cores, reactors, mutual inductors, large motors, etc. The production process of high-temperature oriented silicon steel is long. The production process is generally molten iron → steelmaking → continuous casting → hot coil → pickling → primary cold rolling → decarburization annealing → secondary cold rolling → MgO coating → high-temperature annealing → stretching annealing → notching → slitting. Due to equipment limitations, general private enterprises do not have steel areas and hot rolling production, but only have post-process production equipment. Moreover, due to environmental pressure, there is no pickling production line. Generally, hot coil raw materials are purchased for outsourcing processing, or oriented silicon steel pickled coils are directly purchased, and then post-cold rolling, decarburization annealing and high-temperature annealing and other post-process production are carried out.

[0003] In the production process of the post-process, the decarburization annealing process is particularly important. Decarburization annealing allows a sufficient number of primary grains (secondary crystal nuclei) in the matrix and the primary recrystallization texture and organization that are conducive to their growth; at the same time, the carbon in the steel is removed to below 30ppm, ensuring that it is in a single α-phase during subsequent high-temperature annealing, developing a complete secondary recrystallization organization, removing sulfur and nitrogen from the steel, and eliminating the magnetic aging of the product. However, in the actual decarburization annealing production process, the surface of the strip steel is often blackened after decarburization annealing. The main reason is that the surface oxide scale of the hot-rolled raw material is not cleaned cleanly during pickling. The blackening of the surface affects the decarburization effect, hinders the diffusion of matrix Fe atoms to the surface layer to react with water vapor, and causes the thickness of the generated oxide layer to be thin, affecting the subsequent formation of the glass bottom layer, affecting the magnetic properties of the final product, and may cause gold leakage on the surface of the finished product, so surface quality control after decarburization annealing is crucial.

[0004] The iron oxide scale formed during the hot rolling process is mainly Fe3O4, Fe2O3, and FeO, among which Fe2O3 (reddish brown) is in the outermost layer, Fe3O4 (black) in the middle, and FeO (black) in the innermost layer. The research results show that when the final rolling temperature is 700-900℃, the iron oxide scale formed contains 80-90% FeO and 10-20% Fe3O4. When the final rolling temperature is higher than 900℃, iron will be rapidly oxidized to Fe3O4 and form Fe2O3 in the outermost layer, and fulgenite FeO will be transformed into Fe3O4 during the high-temperature curling process. Therefore, under the high temperature condition of 930-980℃ for the final rolling temperature of oriented silicon steel, the content of FeO fulgenite that is easy to clean on the innermost layer is 10%, the content of Fe3O4 that is difficult to clean in the middle layer is 70-80%, and the content of Fe2O3 on the outermost layer is 10-20%. In view of the great influence of the hot rolling heating furnace temperature and the final rolling temperature of oriented silicon steel on the magnetic properties, it is impossible to reduce the content of surface oxide scale by optimizing the hot rolling process. In addition, the atmosphere in the furnace of the decarburization annealing process is a wet atmosphere with a low content of reducing atmosphere. It is difficult to remove the surface oxide scale through the decarburization annealing process. Therefore, the pickling effect of the surface oxide scale can only be improved by optimizing the pickling process.

[0005] In order to improve the surface pickling effect of oriented silicon steel, the prior art "CN117867506A" proposes a pickling method for oriented silicon steel. This method adopts a secondary pickling method. Although the pickling process is not changed, the secondary pickling increases the production cost and has low production efficiency. Moreover, the pickled coils after the secondary pickling are obviously silver-gray in color of steel. Although the production requirements of the subsequent process are met, whether the finished products produced using the pickled coils have excellent performance is not explained in the present invention; the prior art "CN116875987A" proposes a method for continuous pickling of ordinary oriented silicon steel, which uses the pressure roller of a uncoiler to roll the strip to produce microcracks on the iron oxide scale on the surface of the strip, and then grinds and brushes the surface of the strip, mainly using physical rust removal. The iron oxide scale on the surface of the strip will be unevenly cleaned. Summary of the invention

[0006] The purpose of the present invention is to solve the defects of uneven cleaning of the iron oxide scale on the surface of the strip and low production efficiency caused by the pickling method of oriented silicon steel in the prior art, and therefore propose an oriented silicon steel pickling coil and its preparation method, and an oriented silicon steel finished product. The preparation method of the present invention first reduces the surface of the strip to a certain temperature by rapid cooling with inert gas after hot rolling and curling to prevent the formation of Fe3O4. At the same time, a specific type of pickling accelerator is added during the pickling process, which can promote the cleaning of the iron oxide scale on the surface of the hot-rolled strip, coordinately control the pickling time of the strip, and ensure the consistency of the pickling quality of the entire strip surface. The iron oxide scale on the surface of the oriented silicon steel pickling coil prepared by the method of the present invention is pickled clean, and the surface of the strip has a metallic luster after decarburization annealing, without defects such as blackening and darkening. At the same time, the oriented silicon steel finished product produced by using the pickling coil raw material has excellent magnetic properties and excellent coating adhesion.

[0007] The first aspect of the present invention provides a method for preparing an oriented silicon steel pickling coil, the method comprising the following steps:

[0008] Step S1, heating the continuous casting slab, dephosphorizing the heated continuous casting slab, and hot rolling the dephosphorizing continuous casting slab to obtain a hot rolled coil;

[0009] Step S2, cooling the hot-rolled coil in a protective atmosphere to obtain a steel strip, and subjecting the steel strip to a shot blasting treatment;

[0010] Step S3, pickling the strip after shot blasting in an acid solution to which a pickling accelerator is added. During the pickling process, the pickling time of the strip head is 90 to 100 seconds, and the pickling time of the strip tail is 110 to 120 seconds, wherein the pickling accelerator includes a complexing agent composed of sulfite and a furanedione derivative containing a carbon-carbon double bond.

[0011] Preferably, the sulfite is hydrated ammonium sulfite or sodium sulfite; the furandione derivative containing a carbon-carbon double bond is an organic substance in which both ends of an alkane chain are substituted with a carbon-carbon double bond and furandione, respectively.

[0012] More preferably, the furandione derivative containing a carbon-carbon double bond is 3-octadecane-dihydro-2,5-furandione.

[0013] Further preferably, based on the total mass of the pickling accelerator being 100%, the content of hydrated ammonium sulfite or sodium sulfite is ≥30%, and the content of 3-octadecane-dihydro-2,5-furandione is ≤5%.

[0014] More preferably, based on 100% of the total mass of the pickling accelerator, the content of hydrated ammonium sulfite or sodium sulfite is 30-35%, and the content of 3-octadecane-dihydro-2,5-furandione is 3-5%.

[0015] More preferably, in the acid solution to which the pickling accelerator is added, the concentration of the pickling accelerator is 0.3-0.5%; the acid solution is hydrochloric acid, the concentration of the hydrochloric acid is 150-200 g / L, and the temperature of the hydrochloric acid is 85-90°C.

[0016] Preferably, the pressure of the dephosphorization water used in the dephosphorization treatment is ≥200 bar; in the shot blasting treatment, the shot blasting speed is 60-80 m / s.

[0017] Preferably, the chemical composition of the continuous casting slab, measured by weight percentage, includes: C: 0.030-0.045%, Si: 3.05-3.30%, Mn: 0.15-0.25%, Als: 0.015-0.025%, N: 0.0080-0.0100%, S: 0.0050-0.0100%, Cu: 0.45-0.60%, P: ≤0.020%, Ti: ≤0.003%, and the rest is Fe and unavoidable impurities.

[0018] The second aspect of the present invention provides an oriented silicon steel pickled coil obtained according to the above-mentioned preparation method.

[0019] The third aspect of the present invention provides a oriented silicon steel product, which is obtained by subjecting the above-mentioned oriented silicon steel pickling coil to a primary cold rolling, decarburization annealing, secondary cold rolling and coating.

[0020] The oriented silicon steel pickling coil and its preparation method, and the oriented silicon steel finished product described in the present invention have at least the following beneficial effects:

[0021] (1) In the present invention, firstly, after hot rolling and curling, the surface of the steel strip is cooled to a certain temperature by means of rapid cooling with inert gas to prevent the formation of Fe3O4. Meanwhile, a pickling accelerator is added during the pickling process to promote the cleaning of the oxide scale on the surface of the hot-rolled steel strip. The pickling time of the steel strip is controlled in coordination to ensure the consistency of the pickling quality of the surface of the whole steel strip. The surface oxide scale of the produced oriented silicon steel pickled roll is pickled cleanly. After decarburization annealing, the surface of the steel strip presents a metallic luster without defects such as blackening and darkening. The oriented silicon steel finished product produced by using the pickled roll raw material has the characteristics of excellent magnetic properties and excellent coating adhesion.

[0022] (2) Under the preferred conditions, a pickling accelerator of suitable type and content is selected, and relevant parameters of the oriented silicon steel pickling coil in the preparation process are reasonably regulated. The thickness of the oriented silicon steel pickling coil finally prepared is 2.3-2.6 mm, and the surface whiteness of the strip is above 65. At the same time, after decarburization annealing in the subsequent process, the surface of the strip presents a metallic luster, and there are no defects such as blackening and darkening on the surface. The oriented silicon steel pickling coil can be used to produce oriented silicon steel products of different thicknesses, among which the brand number of 0.27 mm thickness is 27Q095-110, the brand number of 0.23 mm thickness is 23Q085-100, and the brand number of 0.20 mm thickness is 20Q080-090. The coating adhesion of the oriented silicon steel products is all level 1, which meets the requirements of excellent magnetic properties and excellent coating adhesion of the oriented silicon steel products. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a physical picture of the pickled oriented silicon steel coil prepared in Example 1 of the present invention;

[0024] Figure 2 The oriented silicon steel product is prepared from the oriented silicon steel pickling coil obtained in Example 1 of the present invention;

[0025] Figure 3 This is a physical picture of the oriented silicon steel pickling coil prepared in Comparative Example 1 of the present invention;

[0026] Figure 4 The oriented silicon steel finished product is prepared from the oriented silicon steel pickling coil obtained in Comparative Example 1 in the present invention;

[0027] Figure 5 This is a physical picture of the oriented silicon steel pickling coil prepared in Comparative Example 2 of the present invention. DETAILED DESCRIPTION

[0028] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0029] Since the iron oxide scale FeO has a Fuji structure and is easy to clean, but under the conditions of 350-570℃, the Fuji FeO is unstable and will transform into Fe3O4 which is not easy to clean. Therefore, in order to reduce the possibility of FeO transforming into Fe3O4, the hot rolled coil is quenched in a protective atmosphere after coiling, and the coil temperature is quickly reduced to below 350℃, which can effectively prevent the formation of Fe3O4 which is difficult to clean.

[0030] In order to ensure that the iron oxide scale on the surface of the strip is cleaned, the pickling speed of the strip is determined according to the length of the acid tank to ensure that the pickling time of the strip is not less than 90s. At the same time, to avoid over-pickling of the strip, while adding inhibitors to the acid solution, the pickling time of the strip is required to be no more than 120s; because the outer ring of the strip cools faster and the inner ring cools slower after hot rolling and curling, and the time in the high temperature zone is longer, the inner ring is generally oxidized more seriously than the outer ring, so during pickling, in order to ensure the consistency of the pickling quality of the entire strip surface, the pickling time of the strip head can be controlled at 90-100s, and the pickling time of the strip tail can be controlled at 110-120s. In this article, the strip head refers to the strip head to 1 / 3 of the length, and the strip tail refers to the length from 2 / 3 to the tail.

[0031] In order to promote the cleaning of the iron oxide scale on the surface of the hot-rolled strip, a pickling accelerator is added to the acid solution in the pickling process; a complexing agent composed of sulfite and a furandione derivative containing a carbon-carbon double bond is used as a reducing agent. The complexing agent reacts with the Fe3O4 and Fe2O3 on the outside of the iron oxide scale that are difficult to clean, generating Fuji structure FeO that is easy to pickle, thereby promoting the cleaning of the iron oxide scale.

[0032] The first aspect of the present invention provides a method for preparing an oriented silicon steel pickling coil, the method comprising the following steps:

[0033] Step S1, heating the continuous casting slab, dephosphorizing the heated continuous casting slab, and hot rolling the dephosphorizing continuous casting slab to obtain a hot rolled coil;

[0034] Step S2, cooling the hot-rolled coil in a protective atmosphere to obtain a steel strip, and subjecting the steel strip to a shot blasting treatment;

[0035] Step S3, pickling the shot blasted strip in an acid solution to which a pickling accelerator is added to obtain a pickled plate. During the pickling process, the pickling time of the strip head is 90 to 100 seconds, and the pickling time of the strip tail is 110 to 120 seconds, wherein the pickling accelerator includes a complexing agent composed of a sulfite and a furanedione derivative containing a carbon-carbon double bond.

[0036] In a specific embodiment of the preparation method of the present invention, molten steel is continuously cast into a slab with a thickness of 200 to 230 mm.

[0037] In a specific embodiment of the preparation method of the present invention, the chemical composition of the continuous casting slab includes, by weight percentage: C: 0.030-0.045%, for example, 0.030%, 0.035%, 0.037%, 0.038%, 0.039%, 0.040% or 0.045%; Si: 3.05-3.30%, for example, 3.05%, 3.10%, 3.16%, 3.25% or 3.30%; Mn: 0.15-0.25%, for example, 0.15%, 0.19%, 0.20% or 0.25%; Als: 0.015-0.025%, for example, 0.015%, 0.020%, 0.023% or 0.025%; N: 0.0080-0.0100%, For example, it can be 0.0080%, 0.0085%, 0.0090%, 0.0095% or 0.0100%; S: 0.0050-0.0100%, for example, it can be 0.0050%, 0.0055%, 0.0060%, 0.0065%, 0.0070%, 0.0080%, 0.0090% or 0.0100%; Cu: 0.45-0.60%, for example, it can be 0.45%, 0.48%, 0.49%, 0.50% or 0.60%; P: ≤0.020%, for example, it can be 0.013%, 0.014% or 0.015%; Ti: ≤0.003%, for example, it can be 0.0013%, 0.0018% or 0.0020%; the rest is Fe and unavoidable impurities.

[0038] In the continuous casting slab, if the carbon content is less than 0.030%, the amount of γ phase will be reduced, or even no phase change will occur. At the same time, hot rolling and cold rolling will be difficult, and the hot-rolled plate will be prone to transverse cracks. If the carbon content is greater than 0.045%, the decarburization process will be difficult to decarburize, and the solid solution temperature of MnS will be increased, and the ingot needs a higher heating temperature. If the silicon content is less than 3.05%, the magnetic properties of the finished product will be reduced. Although a certain Si content can improve the magnetic properties, when the silicon content is greater than 3.30%, the inhibitor's inhibitory ability is weakened, which is not conducive to the development of secondary recrystallization. At the same time, if the Si content is too high, it will hinder the dynamic recrystallization of hot rolling, and the hot-rolled plate structure and composition will be uneven. MnS is used as an inhibitor. If the manganese content is less than 0.15%, the amount of MnS will be reduced, and the inhibitory ability will be insufficient. If the manganese content is greater than 0.25%, there will be too many MnS inhibitors, which is not conducive to secondary recrystallization. Als (acid-soluble aluminum) is an important inhibitor. If the acid-soluble aluminum content is less than 0.015%, the amount of AlN will be insufficient, which will reduce the recrystallization rate. Low inhibition ability, acid-soluble aluminum content greater than 0.025% will lead to surface quality problems such as gold leakage in the bottom layer of the finished product; nitrogen content less than 0.0080% will lead to insufficient AlN inhibitors, and when the nitrogen content is greater than 0.0100%, bubble defects are prone to occur in the finished product; sulfur content less than 0.0050% will lead to a decrease in the amount of MnS and insufficient inhibition ability, and sulfur content greater than 0.0100% will lead to difficulty in desulfurization during high-temperature purification; Cu2S, as an inhibitor in ordinary oriented silicon steel, can also expand the γ phase region. Copper content less than 0.45% will reduce the number of Cu2S inhibitors, and copper content greater than 0.60% will cause CuO to appear in the oxide layer on the surface of the matrix, affecting the decarburization efficiency; phosphorus content greater than 0.020% will lead to uneven distribution of MnS in the hot-rolled plate and reduce the magnetic properties of the finished product; titanium, as an impurity element, can form TiN with N element when the titanium content is greater than 0.003%, reducing the N content and forming stable carbides to hinder decarburization.

[0039] In a specific embodiment of the preparation method of the present invention, the continuous casting slab is directly loaded into a heating furnace for heating, the temperature of the soaking section of the heating furnace is controlled at 1270-1320° C., and the total heating time is 250-300 min.

[0040] In a specific embodiment of the preparation method of the present invention, in order to reduce the content of iron oxide scale before rough rolling, the pressure of the dephosphorization water used in the dephosphorization treatment is ≥200 bar. When the pressure of the dephosphorization water is less than 200 bar, the iron oxide scale on the surface of the strip is not completely removed, and the subsequent pickling is not thorough, which hinders the decarburization effect and affects the magnetic properties of the finished product.

[0041] In a specific embodiment of the preparation method of the present invention, the continuous casting slab after dephosphorization treatment is subjected to hot rolling, wherein the hot rolling includes rough rolling and finish rolling. Specifically, the continuous casting slab after dephosphorization treatment is rough rolled to an intermediate billet of 40 to 50 mm, the rough rolling temperature is 1070 to 1140°C, and then the intermediate billet is finish rolled to a strip with a thickness of 2.2 to 2.6 mm, the final rolling temperature is 940 to 970°C, and the coiling temperature is 540 to 570°C.

[0042] In the actual operation process of cooling the hot rolled coil in a protective atmosphere, when the strip temperature drops below 350° C., N2 cooling can be stopped and air cooling can be selected.

[0043] In a specific embodiment of the preparation method of the present invention, during the shot blasting treatment, the shot blasting speed is 60 to 80 m / s, for example, it can be 60 m / s, 65 m / s, 70 m / s or 80 m / s; when the shot blasting speed is less than 60 m / s, the iron oxide scale on the surface of the strip is not completely broken, and when the shot blasting speed is greater than 80 m / s, pits are prone to appear on the surface of the strip, and the increase in roughness leads to an increase in the rolling force during the cold rolling process, and the rolling force is unstable.

[0044] In a specific embodiment of the preparation method of the present invention, the sulfite is hydrated ammonium sulfite or sodium sulfite; the furandione derivative containing carbon-carbon double bonds is an organic substance in which the two ends of the alkane chain are substituted by carbon-carbon double bonds and furandione respectively; in a preferred case, the furandione derivative containing carbon-carbon double bonds in the alkane is 3-octadecane-dihydro-2,5-furandione. In this article, the pickling accelerator also includes a surfactant, a stabilizer and water, wherein the surfactant is sodium alkylbenzene sulfonate and / or sodium dodecylbenzene sulfonate, and the stabilizer is 1,4-butynediol.

[0045] In a specific embodiment of the preparation method of the present invention, based on the total mass of the pickling accelerator as 100%, the content of hydrated ammonium sulfite or sodium sulfite is ≥30%. When the content of hydrated ammonium sulfite or sodium sulfite is less than 30%, the surface oxide scale of the strip steel will not be pickled cleanly; the content of 3-octadecane-dihydro-2,5-furandione is ≤5%. In a preferred embodiment, based on the total mass of the pickling accelerator as 100%, the content of hydrated ammonium sulfite or sodium sulfite is 30-35%, for example, 30%, 31%, 32%, 33%, 34% or 35%; the content of 3-octadecane-dihydro-2,5-furandione is 3-5%, for example, 3%, 4% or 5%.

[0046] In a preferred embodiment of the preparation method of the present invention, in the acid solution to which the pickling accelerator is added, the concentration of the pickling accelerator is 0.3-0.5%, for example, 0.3%, 0.4% or 0.5%. When the concentration of the pickling accelerator is less than 0.3%, the oxide scale on the surface of the strip will not be pickled cleanly.

[0047] In a specific embodiment of the preparation method of the present invention, the acid solution is hydrochloric acid, the concentration of the hydrochloric acid is 150-200 g / L, and the temperature of the hydrochloric acid is 85-90°C.

[0048] In a specific embodiment of the preparation method of the present invention, the silicon content in the oriented silicon steel is high, and the weld is prone to breakage during the continuous production process. Therefore, the quality of the weld is more important during the continuous production process. In order to reduce the influence of the pickling accelerator on the weld quality, the crescent shear blade surface at the head and tail welds of the strip is oiled; at the same time, in order to reduce the contact time between the pickling accelerator and the weld, the strip speed is increased when the weld enters the acid solution, and restored to normal speed when the weld exits the acid solution. Taking the acid tank length of 120m of the domestic continuous rolling mill as an example, when the weld enters the acid tank, the pickling speed is increased from 60m / min to 80m / min, and when the weld exits the acid tank, the pickling speed is restored from 80m / min to 60m / min.

[0049] In a specific embodiment of the preparation method of the present invention, the pickled plate is washed in a rinsing tank and then dried, and the rinsing temperature is 50-90°C.

[0050] The second aspect of the present invention provides an oriented silicon steel pickled coil obtained according to the above-mentioned preparation method.

[0051] The third aspect of the present invention proposes a oriented silicon steel product, which is obtained by subjecting the oriented silicon steel pickling coil mentioned above to a single cold rolling, decarburization annealing, secondary cold rolling and coating. The specific operation process is: the oriented silicon steel pickling coil is sequentially subjected to a single cold rolling, decarburization annealing, secondary cold rolling, magnesium oxide coating, high temperature annealing, stretching annealing, notching and slitting. In this article, the detailed operation processes of the single cold rolling, decarburization annealing, secondary cold rolling, magnesium oxide coating, high temperature annealing, stretching annealing, notching and slitting are all conventional technical means in the field.

[0052] The experimental methods or test methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials are obtained from conventional commercial channels or prepared by conventional methods unless otherwise specified.

[0053] Example 1

[0054] A method for preparing an oriented silicon steel pickling coil, the method comprising the following steps:

[0055] Step S1, molten steel is continuously cast into a continuous casting slab with a thickness of 230 mm, and the chemical composition of the continuous casting slab includes, by weight percentage: C: 0.038%, Si: 3.25%, Mn: 0.20%, Als: 0.023%, N: 0.0095%, S: 0.0065%, Cu: 0.50%, P: 0.013%, Ti: 0.0013%, and the rest is Fe and unavoidable impurities, and the continuous casting slab is directly loaded into a heating furnace, the temperature of the heating furnace soaking section is 1295°C, and the total heating time is 280min. The heated continuous casting slab is dephosphorized at a dephosphorization water pressure of 210 bar, and the dephosphorized continuous casting slab is roughly rolled to 42 mm at 1110°C to obtain an intermediate slab, and then the intermediate slab is finish rolled to a thickness of 2.3 mm, the final rolling temperature is 955°C, the coiling temperature is 550°C, and the hot rolled coil is produced;

[0056] Step S2, after coiling, the hot rolled coil is first cooled to 350° C. in N2, and then air-cooled to obtain a steel strip, and the steel strip is shot blasted at a shot blasting speed of 65 m / s;

[0057] Step S3, pickling the strip steel after shot blasting in hydrochloric acid to which a pickling accelerator is added, wherein the concentration of the hydrochloric acid is 180 g / L, the temperature of the hydrochloric acid is 85° C., the pickling accelerator is composed of 33% of ammonium sulfite hydrate, 5% of 3-octadecane-dihydro-2,5-furandione, 3% of sodium dodecylbenzenesulfonate (surfactant), 3% of 1,4-butynediol (stabilizer) and 56% of water, and the concentration of the pickling accelerator in the acid solution to which the pickling accelerator is added is 0.4%; The tank length is 120m. During the pickling process, the pickling speed from the head to 1 / 3 of the strip is 70m / min, and the pickling speed from 2 / 3 to the tail is 60m / min. In continuous production, the crescent shear blade surface at the strip weld is oiled. When the weld enters the acid tank, the pickling speed is 80m / min. When the weld exits the acid tank, the pickling speed is restored to 70m / min. After the pickling is completed, the pickled plate is obtained. The pickled plate is cleaned in a rinsing tank and then dried. The rinsing temperature is 60℃ to obtain the oriented silicon steel pickled coil A1.

[0058] The surface whiteness of the oriented silicon steel pickled coil A1 is 65; the hit rate of 27Q095 grade produced by oriented silicon steel pickled coil A1 is more than 50%, the hit rate of 23Q090 grade is more than 50%, the hit rate of 20Q085 grade is more than 40%, and the coating adhesion is level 1.

[0059] Example 2

[0060] A method for preparing an oriented silicon steel pickling coil, the method comprising the following steps:

[0061] Step S1, molten steel is continuously cast into a continuous casting slab with a thickness of 230 mm, and the chemical composition of the continuous casting slab includes, by weight percentage: C: 0.037%, Si: 3.16%, Mn: 0.19%, Als: 0.020%, N: 0.0090%, S: 0.0060%, Cu: 0.48%, P: 0.015%, Ti: 0.0018%, and the rest is Fe and inevitable impurities, and the continuous casting slab is directly loaded into a heating furnace, the temperature of the heating furnace soaking section is 1280°C, and the total heating time is 280min, and the heated continuous casting slab is dephosphorized at a dephosphorization water pressure of 210bar, and the dephosphorized continuous casting slab is roughly rolled to 45mm at 1100°C to obtain an intermediate slab, and then the intermediate slab is finish rolled to a thickness of 2.3mm, the final rolling temperature is 948°C, the coiling temperature is 548°C, and the hot rolled coil is produced;

[0062] Step S2, after coiling, the hot rolled coil is first cooled to 350° C. in N2, and then air-cooled to obtain a steel strip, and the steel strip is shot blasted at a shot blasting speed of 65 m / s;

[0063] Step S3, pickling the strip steel after shot blasting in hydrochloric acid to which a pickling accelerator is added, wherein the concentration of the hydrochloric acid is 165 g / L, the temperature of the hydrochloric acid is 84° C., the pickling accelerator is composed of 30% sodium sulfite, 4% 3-octadecane-dihydro-2,5-furandione, 3% sodium alkylbenzene sulfonate (surfactant), 3% 1,4-butynediol (stabilizer) and 60% water, and the concentration of the pickling accelerator in the acid solution to which the pickling accelerator is added is 0.3%; the acid tank length is 1000 μm, the temperature of the hydrochloric acid is 84° C., the pickling accelerator is 200 μm, the concentration of the pickling accelerator is 100 μm, the temperature of the pickling accelerator is 84° C., the pickling accelerator is 200 μm, the concentration of the pickling accelerator is 200 μm, the concentration of the pickling accelerator is 0.3%, the acid tank length is 1000 μm, the temperature of the pickling accelerator is 84° C., the pickling accelerator is 200 μm, the concentration of the pickling accelerator is 200 μm, the concentration of the pickling accelerator is 0.3%, the concentration of the pickling accelerator is 0.3%, the temperature of the pickling accelerator is 84° C., the concentration of the pickling accelerator is 1000 μm, the temperature of the pickling accelerator is 84° C., the concentration of the pickling accelerator is 2000 μm, the temperature of the pickling accelerator is 84° C., the concentration of the pickling accelerator The pickling speed is 120m. During the pickling process, the pickling speed from the head to 1 / 3 of the strip is 75m / min, and the pickling speed from 2 / 3 to the tail is 65m / min. In continuous production, the crescent shear blade surface at the strip weld is oiled. When the weld enters the acid tank, the pickling speed is 80m / min. When the weld comes out of the acid tank, the pickling speed is restored to 65m / min. After the pickling is completed, the pickled plate is obtained. The pickled plate is cleaned in a rinsing tank and then dried. The rinsing temperature is 60℃ to obtain the oriented silicon steel pickled coil A2.

[0064] The surface whiteness of the oriented silicon steel pickled coil A2 is 63; the hit rate of 27Q095 grade produced by oriented silicon steel pickled coil A2 is more than 45%, the hit rate of 23Q090 grade is more than 45%, the hit rate of 20Q085 grade is more than 35%, and the coating adhesion is level 1.

[0065] Example 3

[0066] A method for preparing an oriented silicon steel pickling coil, the method comprising the following steps:

[0067] Step S1, molten steel is continuously cast into a continuous casting slab with a thickness of 230 mm, and the chemical composition of the continuous casting slab includes, by weight percentage: C: 0.039%, Si: 3.10%, Mn: 0.20%, Als: 0.020%, N: 0.0085%, S: 0.0065%, Cu: 0.49%, P: 0.014%, Ti: 0.0020%, and the rest is Fe and inevitable impurities, and the continuous casting slab is directly loaded into a heating furnace, the temperature of the heating furnace soaking section is 1285°C, and the total heating time is 280min. The heated continuous casting slab is dephosphorized at a dephosphorization water pressure of 205bar, and the dephosphorized continuous casting slab is roughly rolled to 42mm at 1085°C to obtain an intermediate slab, and then the intermediate slab is finish rolled to a thickness of 2.3mm, the final rolling temperature is 945°C, the coiling temperature is 545°C, and the hot rolled coil is produced;

[0068] Step S2, after coiling, the hot rolled coil is first cooled to 350° C. in N2, and then air-cooled to obtain a steel strip, and the steel strip is shot blasted at a shot blasting speed of 65 m / s;

[0069] Step S3, pickling the strip steel after shot blasting in hydrochloric acid to which a pickling accelerator is added, wherein the concentration of the hydrochloric acid is 155 g / L, the temperature of the hydrochloric acid is 86° C., the pickling accelerator is composed of 30% sodium sulfite, 3% 3-octadecane-dihydro-2,5-furandione, 3% sodium alkylbenzene sulfonate (surfactant), 3% 1,4-butynediol (stabilizer) and 61% water, and the concentration of the pickling accelerator in the acid solution to which the pickling accelerator is added is 0.25%; the acid tank length ...0 g / L, the temperature of the hydrochloric acid is 86° C., the pickling accelerator is 150 g / L, the temperature of the hydrochloric acid is 86° C., the pickling accelerator is 150 g / L, the temperature of the hydrochloric acid is 86° C., the pickling accelerator is 150 g / L, the temperature of the hydrochloric acid is 86° C., the pickling accelerator is 150 g / L, the temperature of the hydrochloric acid is 86° C., the concentration of the pickling accelerator is 150 g / L, the The length is 120m. During the pickling process, the pickling speed from the head to 1 / 3 of the strip is 80m / min, and the pickling speed from 2 / 3 to the tail is 65m / min. In continuous production, the crescent shear blade surface at the strip weld is oiled. When the weld enters the acid tank, the pickling speed is 80m / min. When the weld comes out of the acid tank, the pickling speed is restored to 65m / min. After the pickling is completed, the pickled plate is obtained. The pickled plate is cleaned in a rinsing tank and then dried. The rinsing temperature is 60℃ to obtain the oriented silicon steel pickled coil A3.

[0070] The surface whiteness of the oriented silicon steel pickled coil A3 is 60; the hit rate of 27Q095 grade produced by oriented silicon steel pickled coil A3 is more than 40%, the hit rate of 23Q090 grade is more than 40%, the hit rate of 20Q085 grade is more than 30%, and the coating adhesion is level 1.

[0071] Comparative Example 1

[0072] A method for preparing an oriented silicon steel pickling coil, the method comprising the following steps:

[0073] Step S1, molten steel is continuously cast into a continuous casting slab with a thickness of 230 mm, and the chemical composition of the continuous casting slab includes, by weight percentage: C: 0.038%, Si: 3.25%, Mn: 0.20%, Als: 0.023%, N: 0.0095%, S: 0.0065%, Cu: 0.50%, P: 0.013%, Ti: 0.0013%, and the rest is Fe and inevitable impurities, and the continuous casting slab is directly loaded into a heating furnace, the temperature of the heating furnace soaking section is 1270°C, and the total heating time is 280min, and the heated continuous casting slab is dephosphorized at a dephosphorization water pressure of 190bar, and the dephosphorized continuous casting slab is roughly rolled to 42mm at 1070°C to obtain an intermediate slab, and then the intermediate slab is finish rolled to a thickness of 2.3mm, the final rolling temperature is 955°C, the coiling temperature is 550°C, and the hot rolled coil is produced;

[0074] Step S2, after coiling, the hot rolled coil is first cooled to 350° C. in N2, and then air-cooled to obtain a steel strip, and the steel strip is shot blasted at a shot blasting speed of 55 m / s;

[0075] Step S3, pickling the strip after shot blasting in hydrochloric acid, the concentration of hydrochloric acid is 140g / L, the temperature of hydrochloric acid is 85°C; the length of the acid tank is 120m, the pickling speed of the strip is 70m / min, and the pickling plate is obtained after the pickling is completed. The pickled plate is washed in a rinsing tank and then dried. The rinsing temperature is 60°C to obtain the oriented silicon steel pickled coil B1.

[0076] The surface whiteness of the oriented silicon steel pickled coil B1 is 45; the hit rate of 27Q095 grade produced by oriented silicon steel pickled coil B1 is more than 20%, the hit rate of 23Q090 grade is more than 10%, and the hit rate of 20Q085 grade is more than 20%. The coating adhesion is level 2 to 3, and the coating adhesion is unqualified.

[0077] Comparative Example 2

[0078] A method for preparing an oriented silicon steel pickling coil, the method comprising the following steps:

[0079] Step S1, molten steel is continuously cast into a continuous casting slab with a thickness of 230 mm, and the chemical composition of the continuous casting slab includes, by weight percentage: C: 0.038%, Si: 3.13%, Mn: 0.20%, Als: 0.020%, N: 0.0083%, S: 0.0065%, Cu: 0.49%, P: 0.015%, Ti: 0.0020%, and the rest is Fe and inevitable impurities, and the continuous casting slab is directly loaded into a heating furnace, the temperature of the heating furnace soaking section is 1285°C, and the total heating time is 280min, and the heated continuous casting slab is dephosphorized at a dephosphorization water pressure of 190bar, and the dephosphorized continuous casting slab is roughly rolled to 42mm at 1085°C to obtain an intermediate slab, and then the intermediate slab is finish rolled to a thickness of 2.3mm, the final rolling temperature is 945°C, the coiling temperature is 545°C, and the hot rolled coil is produced;

[0080] Step S2, air-cooling the hot-rolled coil after coiling to obtain a steel strip, and performing shot blasting on the steel strip at a shot blasting speed of 50 m / s;

[0081] Step S3, pickling the strip steel after shot blasting in hydrochloric acid added with a pickling accelerator, the concentration of the hydrochloric acid is 140g / L, the temperature of the hydrochloric acid is 85°C, the pickling accelerator is composed of 15% sodium sulfite, 1% 3-octadecane-dihydro-2,5-furandione, 3% sodium alkylbenzene sulfonate (surfactant), 3% 1,4-butynediol (stabilizer) and 75% water, and the concentration of the pickling accelerator in the acid solution added with the pickling accelerator is 0.15%; the length of the acid tank is 120m, the pickling speed of the strip steel is 120m / min, and in continuous production, the crescent shear blade surface at the strip steel weld is oiled, and the pickling is completed to obtain a pickled plate, which is cleaned in a rinsing tank and then dried, and the rinsing temperature is 60°C to obtain an oriented silicon steel pickled roll B2.

[0082] The surface whiteness of the oriented silicon steel pickling coil B2 is 55, and the surface is dark; the oriented silicon steel pickling coil B2 is used to produce 27Q095 grade hit rate of more than 30%, 23Q090 grade hit rate of more than 30%, 20Q085 grade hit rate of more than 30%, and the qualified rate of coating adhesion level 1 is 70%.

[0083] Test Case

[0084] The oriented silicon steel pickled coils A1-A3 and B1-B2 are respectively subjected to primary cold rolling, decarburization annealing, secondary cold rolling, MgO coating, high temperature annealing, stretching annealing, notching and slitting to obtain oriented silicon steel finished products A1-A3 and B1-B2 respectively;

[0085] The magnetic induction properties of the oriented silicon steel products A1-A3 and B1-B2 were tested using the GB / T 3655 method. The test results are shown in Table 1.

[0086] Table 1 Magnetic induction performance test results of A1~A3 and B1~B2 (mean)

[0087]

[0088] According to the results in Table 1, the iron loss P of the oriented silicon steel products with different thicknesses prepared by using the oriented silicon steel pickling rolls A1 to A3 is 1.7 / 50 and magnetic induction B8 are superior to those of the oriented silicon steel finished product prepared from the oriented silicon steel pickling coils B1~B2. This is because in the process of preparing the oriented silicon steel pickling coils, the surface of the strip is firstly cooled to a certain temperature by rapid cooling with inert gas after hot rolling and curling to prevent the formation of Fe3O4, and at the same time, a specific type of pickling accelerator is added during the pickling process to promote the cleaning of the oxide scale on the surface of the hot-rolled strip, and at the same time, the pickling time of the strip is controlled to ensure the consistency of the pickling quality of the entire strip surface. Therefore, the oriented silicon steel pickling coils obtained by the present invention are used to produce oriented silicon steel finished products with excellent magnetic properties, which is of great significance in reducing energy consumption, improving equipment efficiency, and enhancing equipment stability.

[0089] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preparing an oriented silicon steel pickling coil, characterized in that: The preparation method comprises the following steps: Step S1, heating the continuous casting slab, dephosphorizing the heated continuous casting slab, and hot rolling the dephosphorizing continuous casting slab to obtain a hot rolled coil; Step S2, cooling the hot-rolled coil in a protective atmosphere to obtain a steel strip, and subjecting the steel strip to a shot blasting treatment; Step S3, pickling the strip after shot blasting in an acid solution to which a pickling accelerator is added. During the pickling process, the pickling time of the strip head is 90 to 100 seconds, and the pickling time of the strip tail is 110 to 120 seconds, wherein the pickling accelerator includes a complexing agent composed of sulfite and a furanedione derivative containing a carbon-carbon double bond.

2. The method for preparing the oriented silicon steel pickled coil according to claim 1, characterized in that: The sulfite is hydrated ammonium sulfite or sodium sulfite; The furandione derivative containing a carbon-carbon double bond is an organic substance in which the two chain ends of an alkane are substituted by a carbon-carbon double bond and furandione respectively.

3. The method for preparing the oriented silicon steel pickled coil according to claim 2, characterized in that: The furandione derivative containing a carbon-carbon double bond is 3-octadecane-dihydro-2,5-furandione.

4. The method for preparing the oriented silicon steel pickled coil according to claim 3, characterized in that: Based on the total mass of the pickling accelerator being 100%, the content of hydrated ammonium sulfite or sodium sulfite is ≥30%, and the content of 3-octadecane-dihydro-2,5-furandione is ≤5%.

5. The method for preparing the oriented silicon steel pickled coil according to claim 4, characterized in that: Based on the total mass of the pickling accelerator being 100%, the content of hydrated ammonium sulfite or sodium sulfite is 30-35%, and the content of 3-octadecane-dihydro-2,5-furandione is 3-5%.

6. The method for preparing the oriented silicon steel pickled coil according to claim 5, characterized in that: In the acid solution to which the pickling accelerator is added, the concentration of the pickling accelerator is 0.3 to 0.5%; The acid solution is hydrochloric acid, the concentration of the hydrochloric acid is 150-200 g / L, and the temperature of the hydrochloric acid is 85-90°C.

7. The method for preparing the oriented silicon steel pickled coil according to claim 1, characterized in that: The pressure of dephosphorization water used in dephosphorization treatment is ≥200bar; In shot blasting, the shot blasting speed is 60 to 80 m / s.

8. The method for preparing the oriented silicon steel pickled coil according to claim 1, characterized in that: The chemical composition of the continuous casting slab, measured by weight percentage, includes: C: 0.030-0.045%, Si: 3.05-3.30%, Mn: 0.15-0.25%, Als: 0.015-0.025%, N: 0.0080-0.0100%, S: 0.0050-0.0100%, Cu: 0.45-0.60%, P: ≤0.020%, Ti: ≤0.003%, and the rest is Fe and unavoidable impurities.

9. An oriented silicon steel pickled coil obtained according to the preparation method according to any one of claims 1 to 8.

10. A oriented silicon steel product, characterized in that: The oriented silicon steel finished product is obtained by subjecting the oriented silicon steel pickling coil as claimed in claim 9 to primary cold rolling, decarburization annealing, secondary cold rolling and coating.

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