Hot-rolled annealed sheet for non-oriented electrical steel sheet, method for producing same, and method for producing non-oriented electrical steel sheet

Abstract

The average crystal grain size of the cross section in the rolling direction of the pickled steel sheet is 40-250 [mu] m by heating, hot rolling, hot-rolled sheet annealing, shot blasting, and pickling a steel slab containing prescribed amounts of C, Si, Mn, P, S, Al, N, O, Sn, and Sb so as to satisfy prescribed conditions, or by heating, hot rolling, hot-rolled sheet annealing, brushing, and pickling the steel slab so as to satisfy prescribed conditions. A hot-rolled and annealed sheet for a non-oriented electromagnetic steel sheet, which has both prevention of sheet breakage during cold rolling and excellent magnetic properties after annealing of the cold-rolled sheet, is obtained by setting the integrated strength of Fe-Al-based oxides in the surface layer of the steel sheet as determined by X-ray diffraction measurement to 200 cps degrees or less. A non-oriented electrical steel sheet is produced using the hot-rolled and annealed sheet.

Description

Technical Field

[0001] This invention relates to a hot-rolled annealed sheet for non-oriented electromagnetic steel sheets with excellent fracture resistance in cold rolling, a method for manufacturing the same, and a method for manufacturing non-oriented electromagnetic steel sheets using the aforementioned hot-rolled annealed sheet. Background Technology

[0002] In recent years, due to increased environmental awareness, the demand for reducing CO2 emissions and conserving energy has been growing, and there is a strong demand for higher efficiency in electrical equipment, including electric vehicles. Therefore, there is a strong need to improve the iron loss characteristics of non-oriented electromagnetic steel sheets, which are widely used as core materials for motors in electrical equipment. To this end, efforts have been made to improve iron loss by adding large amounts of elements that increase resistivity, such as Si and Al, or by reducing the sheet thickness.

[0003] On the other hand, the large addition of Si, Al and other elements, and the reduction in the final plate thickness will lead to an increase in the manufacturing load during cold rolling. Therefore, it is also important to prevent steel plate fractures and other failures during cold rolling while improving magnetic properties.

[0004] Therefore, in order to solve this problem, techniques such as controlling the annealing temperature of hot-rolled plates and improving toughness to suppress plate fracture in cold rolling have been proposed.

[0005] For example, Patent Document 1 discloses a non-oriented electromagnetic steel sheet containing, by mass%, C: 0.0010–0.0050%, Si: 2.5–4.0%, Al: 0.2–2.0%, Mn: 0.05–2.0%, P: 0.005–0.15%, S: 0.0001–0.0030%, Ti: 0.0005–0.0030%, N: 0.0010–0.0030%, with the balance consisting of Fe and unavoidable impurities. The thickness of the steel base is 0.10 mm or more and 0.35 mm or less. The Al concentration in the depth direction from the surface of the steel base satisfies the relationship shown in Equation (1). Based on this, it can be explained that when the homogenization temperature of the hot-rolled sheet annealing is higher than 1100°C, or when the homogenization time exceeds 300 seconds, steel base fracture may occur during the subsequent cold rolling.

[0006] 0.1≤Al(x≤2μm) / Al(x=10μm)<1.0…(1)

[0007] Here, in the above formula (1), x is the depth [μm] from the surface of the steel substrate, Al (x≤2μm) is the average Al concentration from the surface of the steel substrate to a depth of 2μm, and Al (x=10μm) is the Al concentration at a depth of 10μm.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent Application Publication No. 2018-021241 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] However, the prior art disclosed in the aforementioned patent documents has the following problems.

[0013] According to the inventor's investigation, it was found that controlling the annealing conditions of hot-rolled plates as described in the aforementioned patent document 1 alone is not necessarily able to suppress fracture, and it is difficult to balance the fracture resistance in cold rolling with the good magnetic properties of cold-rolled plates after annealing.

[0014] The present invention was made in view of the above-mentioned problems, and aims to provide a hot-rolled annealed sheet for non-oriented electromagnetic steel sheet that prevents breakage during cold rolling after hot-rolled sheet annealing and has excellent magnetic properties after cold-rolled sheet annealing, as well as a method for manufacturing the same and a method for manufacturing non-oriented electromagnetic steel sheet using the above-mentioned hot-rolled annealed sheet.

[0015] Methods for solving problems

[0016] The hot-rolled annealed sheet for non-oriented electromagnetic steel sheet of the present invention, which advantageously solves the above problems, is configured as follows.

[0017] [1] A hot-rolled annealed sheet for non-oriented electromagnetic steel sheet, comprising, by mass%, C: less than 0.0050%, Si: 2.0 to 5.0%, Mn: 0.2 to 2.0%, P: less than 0.030%, S: less than 0.0050%, Al: 0.25 to 2.50%, N: less than 0.0050%, O: less than 0.0050%, one or more of Sn and Sb: totaling 0.01 to 0.20%, and the balance being composed of Fe and unavoidable impurities, the average grain size of the cross section in the rolling direction of the steel sheet being 40 to 250 μm, and the integral intensity of the Fe-Al oxide on the surface of the steel sheet, as determined by X-ray diffraction, being less than 200 cps·degree.

[0018] [2] The hot-rolled annealed sheet for non-oriented electromagnetic steel sheet according to [1] above, wherein, based on the above composition, it also contains, by mass%, one or more components selected from groups A to D below.

[0019] Group A: Selected from one or more of Ca, Mg, and REM: Total 0.0010–0.0080%

[0020] Group B: Selected from one or more of Cr, Mo, Cu, and Ni: Total 0.01–0.60%

[0021] Group C: Selected from one or more of Ti, Nb, and V: Total 0.0005–0.0030%

[0022] Group D: B: 0.0001~0.0020%

[0023] [3] The hot-rolled annealed sheet for non-oriented electromagnetic steel sheet according to [1] or [2] above is characterized in that, based on the above composition, it further contains, by mass%, one or more components selected from the following groups E to J.

[0024] ·Group E: Zn: 0.001~0.010%

[0025] Group F: Selected from one or more of Zr, Ta, W, and Se: Total 0.001–0.010%

[0026] Group G: Selected from one or more of Ga and Ge: Total 0.0001~0.0200%

[0027] Group H: Selected from one or more of Pb and Bi: Total 0.00005~0.0020%

[0028] ·Group I: Co: 0.001~0.100%

[0029] Group J: As: 0.0005~0.020%

[0030] The method for manufacturing a hot-rolled annealed sheet for non-oriented electromagnetic steel sheet according to the present invention, which advantageously solves the above-mentioned problems, is configured as follows.

[0031] [4] A method for manufacturing a hot-rolled annealed sheet for non-oriented electromagnetic steel plates, comprising: a hot rolling process, wherein a steel billet is heated and hot-rolled to produce a hot-rolled steel sheet, wherein the steel billet has, by mass%, the following components: C: less than 0.0050%, Si: 2.0-5.0%, Mn: 0.2-2.0%, P: less than 0.030%, S: less than 0.0050%, Al: 0.25-2.50%, N: less than 0.0050%, O: less than 0.0050%, one or more of Sn and Sb: totaling 0.01-0.20%, and the balance being composed of Fe and unavoidable impurities. The composition includes: a hot-rolled steel sheet annealing process, wherein the hot-rolled steel sheet is annealed to produce a hot-rolled annealed sheet; a shot blasting process, wherein the hot-rolled annealed sheet is shot blasted; and a pickling process, wherein the shot-blasted hot-rolled annealed sheet is pickled. In the hot rolling process, the heating temperature of the steel billet is set to below 1150°C, the finishing rolling temperature is set to below 960°C, and the coiling temperature is set to below 700°C. In the hot-rolled steel sheet annealing process, the annealing temperature is set to above 800°C and below 1100°C. In the shot blasting process, the hot-rolled annealed sheet is subjected to a shot density of 10–40 kg / m³. 2 The shot blasting process involves pickling the steel plate after shot blasting under the following conditions: hydrochloric acid concentration of 5% or higher, pickling temperature of 70°C or higher, and pickling time of 10 seconds or more and 120 seconds or less.

[0032] [5] The method for manufacturing hot-rolled annealed sheet for non-oriented electromagnetic steel sheet according to [4] above is characterized in that the steel billet, in addition to the above composition, contains one or more components selected from groups A to D below in terms of mass%.

[0033] Group A: Selected from one or more of Ca, Mg, and REM: Total 0.0010–0.0080%

[0034] Group B: Selected from one or more of Cr, Mo, Cu, and Ni: Total 0.01–0.60%

[0035] Group C: Selected from one or more of Ti, Nb, and V: Total 0.0005–0.0030%

[0036] Group D: B: 0.0001~0.0020%

[0037] [6] The method for manufacturing hot-rolled annealed sheet for non-oriented electromagnetic steel sheet according to [4] or [5] above is characterized in that the steel billet, in addition to the above composition, contains one or more components selected from the following groups E to J by mass%.

[0038] ·Group E: Zn: 0.001~0.010%

[0039] Group F: Selected from one or more of Zr, Ta, W, and Se: Total 0.001–0.010%

[0040] Group G: Selected from one or more of Ga and Ge: Total 0.0001~0.0200%

[0041] Group H: Selected from one or more of Pb and Bi: Total 0.00005~0.0020%

[0042] ·Group I: Co: 0.001~0.100%

[0043] Group J: As: 0.0005~0.020%

[0044] [7] The method for manufacturing a hot-rolled annealed sheet for non-oriented electromagnetic steel sheet according to any one of [4] to [6] above is characterized in that, before annealing the hot-rolled steel sheet, the hot-rolled steel sheet is subjected to rolling and / or stretching bending processing with an elongation of 0.1 to 10.0%.

[0045] [8] The method for manufacturing hot-rolled annealed sheet for non-oriented electromagnetic steel sheet according to any one of [4] to [7] above is characterized in that, after the pickling process above, the surface and back of the pickled steel sheet are brushed.

[0046] The method for manufacturing the non-oriented electromagnetic steel sheet of the present invention, which advantageously solves the above-mentioned problems, is configured as follows.

[0047] [9] A method for manufacturing a non-oriented electromagnetic steel sheet, wherein the hot-rolled annealed sheet obtained in any one of [4] to [8] above is subjected to one cold rolling or two or more cold rolling processes including intermediate annealing to produce a cold-rolled sheet with a final sheet thickness, and the cold-rolled sheet is subjected to cold-rolled annealing at a homogenization temperature of 700 to 1100°C to produce a cold-rolled annealed sheet.

[0048] Another method for manufacturing the hot-rolled annealed sheet for the non-oriented electromagnetic steel sheet of the present invention, which advantageously solves the above-mentioned problems, is configured as follows.

[0049]

[10] A method for manufacturing a hot-rolled annealed sheet for non-oriented electromagnetic steel plates, comprising: a hot rolling process, wherein a steel billet is heated and hot-rolled to produce a hot-rolled steel sheet, the steel billet having, by mass%, a composition comprising: C: less than 0.0050%, Si: 2.0 to 5.0%, Mn: 0.2 to 2.0%, P: less than 0.030%, S: less than 0.0050%, Al: 0.25 to 2.50%, N: less than 0.0050%, O: less than 0.0050%, one or more of Sn and Sb: totaling 0.01 to 0.20%, and the balance being Fe and unavoidable impurities; and a hot-rolled sheet annealing process, wherein... The hot-rolled steel sheet is annealed to produce a hot-rolled annealed sheet; a brushing process is performed, wherein the hot-rolled annealed sheet is brushed; and a pickling process is performed, wherein the brushed hot-rolled annealed sheet is pickled. In the hot rolling process, the heating temperature of the steel billet is set to below 1150°C, the finishing rolling temperature is set to below 960°C, and the coiling temperature is set to below 700°C. In the hot-rolled sheet annealing process, the annealing temperature is set to above 800°C and below 1100°C. In the pickling process, the brushed steel sheet is pickled under the conditions of a hydrochloric acid concentration of above 5%, a pickling temperature of above 70°C, and a pickling time of above 10s and below 120s.

[0050]

[11] In the manufacturing method of the hot-rolled annealed sheet for non-oriented electromagnetic steel sheet according to

[10] above, the steel billet contains, in addition to the above composition, one or more components selected from groups A to D below in terms of mass%.

[0051] Group A: Selected from one or more of Ca, Mg, and REM: Total 0.0010–0.0080%

[0052] Group B: Selected from one or more of Cr, Mo, Cu, and Ni: Total 0.01–0.60%

[0053] Group C: Selected from one or more of Ti, Nb, and V: Total 0.0005–0.0030%

[0054] Group D: B: 0.0001~0.0020%

[0055]

[12] The method for manufacturing hot-rolled annealed sheet for non-oriented electromagnetic steel sheet according to

[10] or

[11] above is characterized in that the steel billet, in addition to the above composition, contains one or more components selected from the following groups E to J by mass%.

[0056] ·Group E: Zn: 0.001~0.010%

[0057] Group F: Selected from one or more of Zr, Ta, W, and Se: Total 0.001–0.010%

[0058] Group G: Selected from one or more of Ga and Ge: Total 0.0001~0.0200%

[0059] Group H: Selected from one or more of Pb and Bi: Total 0.00005~0.0020%

[0060] ·Group I: Co: 0.001~0.100%

[0061] Group J: As: 0.0005~0.020%

[0062]

[13] The method for manufacturing a hot-rolled annealed sheet for non-oriented electromagnetic steel sheet according to any one of

[10] to

[12] above is characterized in that, before annealing the hot-rolled steel sheet, the hot-rolled steel sheet is subjected to rolling and / or stretching bending processing with an elongation of 0.1 to 10.0%.

[0063]

[14] The method for manufacturing a hot-rolled annealed sheet for non-oriented electromagnetic steel sheet according to any one of

[10] to

[13] above is characterized in that, after the pickling process above, the surface and back of the pickled steel sheet are brushed.

[0064] Another method for manufacturing the non-oriented electromagnetic steel sheet of the present invention, which advantageously solves the above-mentioned problems, is as follows.

[0065]

[15] A method for manufacturing a non-oriented electromagnetic steel sheet, wherein the hot-rolled annealed sheet obtained in any one of

[10] to

[14] above is subjected to one cold rolling or two or more cold rolling processes including intermediate annealing to produce a cold-rolled sheet with a final sheet thickness, and the cold-rolled sheet is subjected to cold-rolled sheet annealing at a homogenization temperature of 700 to 1100°C to produce a cold-rolled annealed sheet.

[0066] Invention Effects

[0067] According to the present invention, non-oriented electromagnetic steel sheets that suppress the fracture of steel sheets during cold rolling and have excellent magnetic properties can be manufactured efficiently. Detailed Implementation

[0068] The inventors conducted in-depth research into the causes of sheet fracture during cold rolling. The results revealed that for steel sheets with a high concentration of Si and Al, as in this invention, not only iron oxides but also Si and Al oxides are formed on the steel sheet surface during hot rolling or annealing. Particularly, a dense Fe-Al oxide scale forms near the interface between the steel substrate and the oxide layer. This Fe-Al oxide scale is poorly soluble in acids, and if it cannot be completely removed during pickling, it promotes wear on the cold rolling rolls and makes the steel sheet prone to fracture. To address this problem, the mechanical and chemical conditions related to oxide scale removal were studied, and suitable conditions for the stable removal of oxide scale, including Fe-Al oxide scale, were found, leading to the development of this invention.

[0069] The following describes the hot-rolled annealed sheet for non-oriented electromagnetic steel sheets according to this embodiment.

[0070] First, the composition of the hot-rolled annealed sheet for non-oriented electromagnetic steel sheet of this embodiment and the reasons for its limitation will be explained. In the following description, unless otherwise specified, "%" refers to "mass %".

[0071] Hot-rolled annealed sheet for non-oriented electromagnetic steel sheets

[0072] The hot-rolled annealed sheet for non-oriented electromagnetic steel sheet of this embodiment contains the following composition by mass%: C: 0.0050% or less, Si: 2.0 to 5.0%, Mn: 0.2 to 2.0% or less, P: 0.030% or less, S: 0.0050% or less, Al: 0.25 to 2.50% or less, N: 0.0050% or less, O: 0.0050% or less, and one or more of Sn and Sb: totaling 0.01 to 0.20%, with the balance consisting of Fe and unavoidable impurities.

[0073] C: Below 0.0050%

[0074] Carbon (C) is an element that forms carbides, thus deteriorating iron loss after final annealing. Furthermore, C increases the hardness of hot-rolled annealed sheets, inducing sheet fracture during cold rolling. Therefore, the C content is set to 0.0050% or less. Preferably, the C content is 0.0030% or less. While there is no particular limitation on the lower limit of the C content, from the viewpoint of improving the toughness of hot-rolled annealed sheets and preventing sheet fracture during cold rolling, it is preferable to set it to 0.0010% or more.

[0075] Si: 2.0–5.0%

[0076] Si has the effect of increasing the resistivity of steel and reducing iron loss after final annealing, so the content is set to 2.0% or more. Preferably, it is 2.7% or more. On the other hand, when the Si content exceeds 5.0%, the hot-rolled annealed sheet becomes excessively hardened and brittle, and is prone to breakage during cold rolling, so the upper limit is set to 5.0%. Preferably, it is 4.5% or less.

[0077] Mn: 0.2~2.0%

[0078] Mn, like Si, is a useful element for reducing iron loss and also improves the toughness of the steel matrix and inhibits sheet fracture during cold rolling. Therefore, the Mn content is set to 0.2% or more, preferably 0.35% or more. On the other hand, when the Mn content exceeds 2.0%, the hot-rolled annealed sheet becomes excessively hardened and prone to fracture during cold rolling, so it is set to 2.0% or less.

[0079] P: below 0.030%

[0080] Polymer (P) has the effect of increasing the strength of steel and can be used to adjust strength. On the other hand, when the P content exceeds 0.030%, the steel becomes embrittled, leading to reduced manufacturability. Therefore, the P content is set to 0.030% or less. From the viewpoint of preventing embrittlement, a P content of 0.015% or less is preferred. It should be noted that there is no particular limitation on the lower limit of the P content, but from the viewpoint of reducing the P removal load, it is preferred to set it to about 0.004%.

[0081] S: Below 0.0050%

[0082] Sulfur segregates at grain boundaries, causing embrittlement in hot-rolled annealed steel sheets. Consequently, the steel sheets are prone to fracture during cold rolling, and fine sulfides form, leading to deterioration of iron loss after final annealing. Therefore, the upper limit of sulfur content is set at 0.0050%. Preferably, the sulfur content is 0.0025% or less. It should be noted that the lower limit of sulfur content is not particularly limited, but from the viewpoint of reducing the sulfur removal load, it is preferably set to about 0.001%.

[0083] Al: 0.25–2.50%

[0084] Al, like Si, increases the resistivity of steel sheets and reduces iron loss after final annealing; therefore, the Al content is set to 0.25% or more. Furthermore, Al forms AlN, which, through a pinning effect, reduces the average grain size of hot-rolled annealed sheets, thus improving fracture resistance during cold rolling. Therefore, the Al content is preferably 0.50% or more, more preferably 0.70% or more. On the other hand, when the Al content exceeds 2.50%, the Fe-Al oxides in the oxide scale generated during hot rolling and annealing increase significantly, and cannot be completely removed by pickling, becoming a cause of sheet fracture during cold rolling. Therefore, the upper limit for Al is set to 2.50%, preferably 2.30% or less.

[0085] N: below 0.0050%

[0086] Nitrogen (N) forms nitrides and can sometimes be the starting point for sheet fracture during cold rolling; therefore, the upper limit for N content is set at 0.0050%. It should be noted that fine nitrides can hinder grain growth and degrade iron loss after final annealing; therefore, the preferred N content is below 0.0035%.

[0087] O: Below 0.0050%

[0088] O forms oxides and can sometimes be the starting point for sheet fracture during cold rolling, so the upper limit is set at 0.0050%. In addition, the formed oxides can hinder the grain growth of ferrite structure and deteriorate the iron loss after final annealing, so the preferred O content is 0.0025% or less.

[0089] One or more of Sn and Sb: Total 0.01–0.20%

[0090] Sn and Sb improve magnetic properties by enhancing the texture after cold rolling and final annealing, and also improve fracture resistance during cold rolling by suppressing the formation of Fe-Al oxides through surface segregation. Therefore, the total content of one or more of Sn and Sb is set to 0.01% or more, preferably 0.02% or more. On the other hand, even if added in excess, the effect will saturate, and the toughness of the hot-rolled annealed sheet will deteriorate, making the sheet prone to fracture during cold rolling. Therefore, the upper limit of the total content of Sn and Sb is set to 0.20%.

[0091] The above are the basic components of the hot-rolled annealed sheet for non-oriented electromagnetic steel sheet according to this embodiment. However, in order to improve various properties, it is preferable to also contain components selected from at least one group of groups A to D below.

[0092] Group A: Selected from one or more of Ca, Mg, and REM: Total 0.0010–0.0080%

[0093] Ca, Mg, and REM have the effect of fixing S in the form of sulfides and improving iron loss. Therefore, it is preferable that one or more of Ca, Mg, and REM are contained in a total of 0.0010% or more. More preferably, 0.0020% or more. On the other hand, when the total content of Ca, Mg, and REM exceeds 0.0080%, excessive inclusions are generated, resulting in reduced manufacturability; therefore, the upper limit is set to 0.0080%. Preferably, the total content of Ca, Mg, and REM is 0.0060% or less.

[0094] Group B: Selected from one or more of Cr, Mo, Cu, and Ni: Total 0.01–0.60%

[0095] Cr, Mo, Cu, and Ni have the effect of increasing the resistivity of steel and improving iron loss. Therefore, it is preferable that one or more of Cr, Mo, Cu, and Ni are contained in a total of 0.01% or more. On the other hand, excessive addition will cause the hot-rolled annealed sheet to harden, making it prone to breakage during cold rolling. Therefore, the upper limit of the total content is preferably set at 0.40%.

[0096] Group C: Selected from one or more of Ti, Nb, and V: Total 0.0005–0.0030%

[0097] Ti, Nb, and V have the effect of refining the microstructure of hot-rolled annealed sheets, improving toughness, and suppressing sheet fracture during cold rolling. Therefore, the content of Ti, Nb, and V is preferably set to 0.0005% or more in total. On the other hand, excessive addition will generate a large amount of fine precipitates, which will significantly hinder grain growth. Therefore, the upper limit of the total content of Ti, Nb, and V is preferably set to 0.0030%.

[0098] Group D: B: 0.0001~0.0020%

[0099] Boron (B) segregates at grain boundaries, thus improving toughness and suppressing sheet fracture during cold rolling. Therefore, the B content is preferably set to 0.0001% or more, more preferably 0.0003% or more. On the other hand, when the B content exceeds 0.0020%, iron boride is formed, and the toughness-improving effect disappears; therefore, the upper limit is preferably set to 0.0020%.

[0100] To enhance various properties, it is preferable to further contain components selected from at least one group of groups E to J below.

[0101] Group E: Zn: 0.001~0.010%

[0102] Zn has the effect of coarsening inclusions and promoting grain growth during final annealing, thereby improving the iron loss of the final annealed plate. Therefore, the Zn content is preferably set to 0.001% or more. On the other hand, even if the Zn content exceeds 0.010%, the above effect will saturate, so the upper limit is preferably set to 0.010%.

[0103] Group F: Selected from one or more of Zr, Ta, W, and Se: Total 0.001–0.010%

[0104] Zr, Ta, W, and Se have the effect of forming precipitates and reducing the particle size of hot-rolled annealed sheets, thereby helping to improve cold-rollability. Therefore, it is preferable to select one or more of Zr, Ta, W, and Se and contain more than 0.001% in total. On the other hand, when the total content exceeds 0.010%, the iron loss of the final annealed sheet may deteriorate, so the upper limit is preferably set to 0.010%.

[0105] Group G: Selected from one or more of Ga and Ge: Total 0.0001–0.0200%

[0106] Ga and Ge have the effect of improving the texture of the final annealed plate and enhancing its magnetic properties. Therefore, it is preferable to contain at least 0.0001% of one or more of Ga and Ge in total. On the other hand, even if the content exceeds 0.0200%, the above-mentioned effects will saturate, so the upper limit is preferably set to 0.0200%.

[0107] Group H: Selected from one or more of Pb and Bi: Total 0.00005–0.0020%

[0108] Pb and Bi have the effect of reducing the grain size of hot-rolled annealed sheets, thereby improving cold-rollability. Therefore, it is preferable to contain at least 0.00005% of one or more of Pb and Bi in total. On the other hand, when the content exceeds 0.0020%, the iron loss of the final annealed sheet deteriorates, so the upper limit is preferably set to 0.0020%.

[0109] Group I: Co: 0.001~0.100%

[0110] Co has the effect of increasing magnetic flux density. Therefore, it is preferable to contain 0.001% or more. On the other hand, when the content exceeds 0.100%, precipitates are formed, which ultimately deteriorates the iron loss of the annealed plate. Therefore, the upper limit is preferably set to 0.100%.

[0111] Group J: As: 0.0005~0.020%

[0112] As segregation at grain boundaries reduces the grain size of hot-rolled annealed sheets, thereby improving cold rollability. Therefore, it is preferable to contain 0.0005% or more. On the other hand, when the content exceeds 0.020%, it promotes grain boundary fracture and reduces cold rollability; therefore, the upper limit is preferably set at 0.020%.

[0113] In the chemical composition of the hot-rolled annealed sheet for non-oriented electromagnetic steel sheet of this embodiment, the balance other than the above-mentioned elements is Fe and unavoidable impurities.

[0114] <Steel microstructure of hot-rolled annealed sheet for non-oriented electromagnetic steel>

[0115] Next, the steel structure of the hot-rolled annealed sheet for non-oriented electromagnetic steel sheet according to this embodiment will be described.

[0116] Average grain size of steel plate in the rolling direction section: 40–250 μm

[0117] When the microstructure of hot-rolled annealed sheet is coarse, the sheet becomes brittle and prone to fracture during cold rolling. Therefore, the average grain size is set to be 250 μm or less. From the viewpoint of suppressing fracture, it is preferable to be 180 μm or less, and more preferably 120 μm or less.

[0118] On the other hand, when the average grain size is less than 40 μm, the hot-rolled annealed sheet will harden, increasing the load during cold rolling and making the sheet prone to breakage. Therefore, it needs to be set to 40 μm or more. Preferably, the average grain size is 60 μm or more.

[0119] Integral strength of Fe-Al oxides on the surface of steel plate: below 200 cps·degrees

[0120] Fe-Al oxides are hard and have poor wettability with lubricating oil. Therefore, if they remain on the steel plate surface, they can damage the rolls during cold rolling, increasing the coefficient of friction and rolling load, making rolling unstable, and ultimately leading to plate breakage. Therefore, it is necessary to thoroughly remove Fe-Al oxides during the pickling process. As an indicator, the integrated intensity of Fe-Al oxides on the surface of the hot-rolled annealed steel plate, as measured by X-ray diffraction, should be below 200 cps·degree.

[0121] <Manufacturing Method of Hot-Rolled Annealed Sheet for Non-Oriented Electromagnetic Steel Sheets>

[0122] Next, the manufacturing method of the hot-rolled annealed sheet for non-oriented electromagnetic steel sheet according to this embodiment will be described.

[0123] The manufacturing method of hot-rolled annealed sheet for non-oriented electromagnetic steel sheet according to this embodiment includes: a hot rolling process of heating and hot rolling a steel billet having the above-mentioned composition to produce a hot-rolled steel sheet; a hot-rolled sheet annealing process of annealing the hot-rolled steel sheet to produce a hot-rolled annealed sheet; a shot blasting process of shot blasting the hot-rolled annealed sheet; and a pickling process of pickling the shot-blasted hot-rolled annealed sheet. In the hot rolling process, the heating temperature of the steel billet is set to 1150°C or lower, the finishing rolling temperature is set to 960°C or lower, and the coiling temperature is set to 700°C or lower. In the hot-rolled sheet annealing process, the annealing temperature is set to 800°C or higher and 1100°C or lower. In the shot blasting process, the hot-rolled annealed sheet is subjected to a shot blasting density of 10 to 40 kg / m³. 2 Shot blasting. Next, in the pickling process, the shot-blasted steel plate is pickled under the conditions of hydrochloric acid concentration of 5% or higher, pickling temperature of 70°C or higher, and pickling time of 10 seconds or more and 120 seconds or less.

[0124] The following is a detailed explanation.

[0125] [Hot rolling process]

[0126] steel billet

[0127] The composition of the steel billet used to manufacture the hot-rolled annealed sheet for non-oriented electromagnetic steel sheets of this embodiment is adjusted to the range described above. The steel can be smelted using known refining processes such as converters, electric furnaces, or vacuum degassing devices, and is not particularly limited. Furthermore, continuous casting is preferred as the method for manufacturing the steel billet. Additionally, scrap iron or direct reduced iron can be used as raw materials. In particular, elements such as Cu and Ni, which are useful for reducing iron loss, can be obtained inexpensively from scrap iron, and are therefore preferred.

[0128] Heating temperature: below 1150℃

[0129] Hot rolling is a process in which a hot-rolled sheet of a specified thickness is obtained by hot rolling immediately after the steel billet with the above-mentioned composition is manufactured, or by hot rolling after cooling to a specified temperature. If the heating temperature of the billet is too high, AlN and MnS will dissolve again and precipitate finely in subsequent processes after hot rolling, deteriorating grain growth and iron loss. Therefore, an upper limit of 1150°C is set. To coarsen AlN and MnS in the billet and improve grain growth and iron loss, the heating temperature is preferably set to 1000°C or higher. Furthermore, from the viewpoint of stabilizing manufacturing by reducing the hot rolling load, 1050°C or higher is more preferable.

[0130] Finishing rolling temperature: below 960℃

[0131] When the finishing temperature of hot-rolled steel exceeds 960°C, the oxide scale on the hot-rolled plate becomes thicker, reducing its pickling properties. Therefore, the finishing temperature is set below 960°C. A preferred finishing temperature is below 920°C. On the other hand, if the finishing temperature is too low, the rolling load increases, thus the lower limit is preferably set at 750°C. More preferably, it is 780°C or higher.

[0132] Winding temperature: below 700℃

[0133] When the coiling temperature exceeds 700°C, the oxide scale increases, especially the Fe-Al oxides thicken, reducing pickling effectiveness; therefore, the upper limit is set at 700°C. Preferably, it is 620°C or lower. On the other hand, if the coiling temperature is too low, the temperature fluctuation increases due to the rapid cooling from the completion of hot rolling to coiling; therefore, the lower limit is preferably set at 450°C. From the viewpoint of coarsening the precipitates during coiling to reduce iron loss, a coiling temperature of 480°C or higher is preferred.

[0134] [Hot-rolled sheet annealing process]

[0135] Annealing temperature of hot-rolled steel sheet: 800~1100℃

[0136] Annealing of hot-rolled plates is carried out to homogenize the microstructure, control the ferrite grain size within a specified range, thereby improving the fracture resistance during cold rolling and improving the magnetic properties after cold rolling and final annealing.

[0137] When the annealing temperature of hot-rolled steel sheet exceeds 1100°C, the microstructure becomes excessively coarse, reducing toughness and making the sheet prone to fracture during cold rolling. Therefore, the annealing temperature needs to be set below 1100°C. A preferred annealing temperature for hot-rolled steel sheet is 1030°C or below. Furthermore, from the viewpoint of suppressing oxide scale growth during annealing of hot-rolled steel sheet, a temperature of 960°C or below is preferred.

[0138] On the other hand, when the annealing temperature of hot-rolled steel is below 800°C, the particle size cannot grow sufficiently, resulting in a decrease in the magnetic properties after annealing. Therefore, it is necessary to set the annealing temperature to 800°C or higher. A preferred annealing temperature for hot-rolled steel is 900°C or higher. The annealing time is not particularly limited, but from the viewpoint of ensuring uniformity, it is preferably set to 10 seconds or higher.

[0139] [Shot blasting process]

[0140] Shot blasting density: 10-40 kg / m³ 2

[0141] Shot blasting of hot-rolled annealed sheets before pickling introduces cracks into the oxide scale, thereby promoting its removal during pickling. This is especially important for Fe-Al oxide scale, which is poorly soluble in acid; therefore, introducing cracks allows the acid to penetrate to the exposed steel substrate and dissolve it from the substrate side of the interface. Thus, a shot blasting density of 10 kg / m³ is required. 2 The above. Preferably, it is 15 kg / m³. 2 above.

[0142] On the other hand, exceeding 40kg / m 2 At this time, not only will cracks be introduced into the oxide scale, but deformation will also occur near the surface of the steel base, becoming the starting point for plate fracture during cold rolling. Therefore, the projection density is set at 40 kg / m³. 2 The preferred projection density is 35 kg / m³. 2 the following.

[0143] When the particle size of the shot blasting particles is too large, even at the same projection density, the number of impacts per unit area will decrease, meaning the number of cracks introduced into the oxide scale will also decrease, leading to reduced pickling performance. Therefore, the average particle size of the shot blasting particles is preferably 0.50 mm or less. From the viewpoint of promoting pickling performance, 0.30 mm or less is more preferable. Conversely, if the particle size is too small, the crack induction effect is weak. Therefore, the average particle size of the shot blasting particles is preferably 0.15 mm or more. The average particle size of the shot blasting particles can be determined, for example, by particle size analysis - laser diffraction / scattering method as described in JIS Z 8825:2013. In addition, if the shot blasting particles are soft, they will deform upon impact with the steel plate, making it difficult to effectively introduce cracks into the oxide scale. Therefore, the Vickers hardness of the shot blasting particles is preferably 400 HV or more.

[0144] [Brushing process (before acid washing)]

[0145] Instead of shot blasting, brushing the hot-rolled annealed plate before pickling can introduce cracks into the oxide scale, thus promoting the removal of oxide scale during pickling.

[0146] To achieve uniform grinding of the steel plate surface, brush grinding preferably uses brush rollers. The raw material of the brush and grinding conditions can be appropriately selected, but from the viewpoint of uniformly grinding along the shape of the steel plate, the bristle material is preferably made of chemical fibers softer than metal. Furthermore, from the viewpoint of effectively introducing cracks into the oxide scale, it is preferable that the brush contains abrasive grains such as alumina-based, silicon carbide-based, or diamond-based grains. During brush grinding, it is preferable to remove abrasive powder and prevent the brush from overheating by spraying cooling water.

[0147] [Pickling process]

[0148] Pickling: Hydrochloric acid concentration above 5%, pickling temperature above 70℃, pickling time above 10s and below 120s

[0149] The pickling process removes the oxide scale from the hot-rolled annealed sheet after shot blasting and brushing. By thoroughly removing iron oxides and Fe-Al oxide scale, sheet breakage during cold rolling can be suppressed. Therefore, the hydrochloric acid concentration is set to 5% or more, preferably 8% or more. There is no particular upper limit, but to prevent over-pickling, the hydrochloric acid concentration is preferably set to 20% or less. To promote pickling, the temperature of the pickling solution (pickling temperature) is set to 70°C or more, preferably 75°C or more. If the pickling temperature is too high, over-pickling is likely to occur, and the evaporation of the pickling solution increases, increasing manufacturing costs; therefore, it is preferably set to 96°C or less. For thorough pickling, the pickling time is set to 10 seconds or more, preferably 15 seconds or more. When it exceeds 120 seconds, hydrogen production increases, and due to hydrogen embrittlement, the sheet is prone to breakage during cold rolling; therefore, the upper limit for the pickling time is set to 120 seconds. As mentioned earlier, pickling properties vary depending on Al content, hot rolling finishing temperature, and coiling temperature. Therefore, pickling accelerators and pickling inhibitors can be added to the pickling solution as needed to adjust the properties.

[0150] Furthermore, in this invention, from the viewpoint of completely removing Fe-Al oxide scale, it is preferable to add the following steps to the descaling process described above.

[0151] Rolling and / or stretching bending processes with an elongation of 0.1% to 10.0% before annealing of hot-rolled sheets.

[0152] By introducing cracks into the oxide scale, particularly Fe-Al based oxide scale, during hot rolling, the steel matrix is ​​exposed, altering the oxidation behavior of the hot-rolled sheet during annealing. Specifically, iron oxides that are relatively soluble in acid are formed in the exposed portion of the steel matrix. Therefore, these iron oxides dissolve during pickling, becoming the starting point for the dissolution of the steel matrix. This dissolution of the steel matrix allows the removal of the Fe-Al based oxide scale.

[0153] Therefore, it is preferable to elongate the hot-rolled sheet through light rolling and / or stretch bending. It is preferable to use a finishing mill or a tension leveler to process the hot-rolled sheet before annealing with an elongation of 0.1% or more. The elongation is preferably 0.3% or more. When it exceeds 10.0%, not only will the above effect saturate, but the average grain size of the hot-rolled annealed sheet will become too large due to strain-induced grain growth. Therefore, the elongation is preferably set to 10.0% or less. More preferably, it is 6.0% or less. It should be noted that when rolling and / or stretch bending with an elongation of 0.1% to 10.0% is performed before annealing the hot-rolled sheet, it is preferable to perform the above processing so that the integral strength of the pickled hot-rolled annealed sheet is 150 cps·degrees or less.

[0154] [Brushing process (after acid washing)]

[0155] The preferred method is to mechanically remove some of the residual Fe-Al oxide scale from the pickling process by brushing the surface and back of the steel plate. However, removing all oxide scale, including Fe-based and Fe-Al-based scale, solely through brushing would require large-scale equipment, leading to increased introduction and maintenance costs.

[0156] Therefore, by removing most of the oxide scale through acid pickling and only removing a portion of the residual Fe-Al oxide scale through brushing, the cost of the equipment can be reduced.

[0157] To achieve uniform grinding of the steel plate surface, brush grinding is preferably performed using brush rollers. The raw materials of the brush and grinding conditions can be appropriately selected, but from the viewpoint of uniform grinding following the shape of the steel plate, it is preferable to use chemical fibers that are softer than metal for the bristles. From the viewpoint of effectively removing Fe-Al based oxide scale, it is preferable that the brush contains abrasive grains such as alumina-based, silicon carbide-based, or diamond-based grains. During brush grinding, it is preferable to remove the grinding powder and prevent the brush from overheating by spraying cooling water.

[0158] It should be noted that when brushing the surface and back of the steel plate after pickling, it is preferable to brush the plate so that the integral strength of the hot-rolled annealed plate after brushing is below 60 cps·degree.

[0159] Next, a method for manufacturing non-oriented electromagnetic steel sheets from hot-rolled annealed sheets obtained by the manufacturing method of the present invention described above will be explained.

[0160] [Cold rolling process]

[0161] Preferably, the hot-rolled annealed sheet after pickling is subjected to one or more cold rolling processes, including intermediate annealing, to produce a cold-rolled sheet of the final thickness. From a production efficiency point of view, a tandem rolling mill is preferred, but a reversible rolling mill can also be used, and rolling can be performed using conventional methods.

[0162] [Final annealing process]

[0163] Final annealing temperature: 700~1100℃

[0164] The aforementioned final annealing process after cold rolling is a process that allows the cold-rolled sheet to recrystallize and grow grains to obtain good magnetic properties. The soaking temperature in the final annealing is preferably set to 700°C or higher, more preferably 800°C or higher. On the other hand, if the soaking temperature in the final annealing is too high, nitriding may occur during annealing, or the grains may become too coarse, leading to deterioration of iron loss. Therefore, it is preferably set to 1100°C or lower, more preferably 1050°C or lower.

[0165] Example

[0166] The embodiments of the present invention are further illustrated by way of examples. It should be noted that the present invention is not limited to the manufacturing conditions and product performance shown in the following embodiments. The desired performance can be achieved within the scope of the present invention.

[0167] (Example 1)

[0168] Steel containing the various components shown in Table 1, with the balance consisting of Fe and unavoidable impurities, is smelted using a conventional refining process and then continuously cast into slabs. Next, the slabs are heated in a gas furnace under the conditions shown in Tables 2-1 and 2-2, and then hot-rolled using roughing and finishing rolling processes to produce hot-rolled plates with a thickness of 1.8 mm and a width of 1200 mm. Afterward, the hot-rolled plates are hot-rolled and annealed, followed by pickling to obtain hot-rolled annealed plates. At this point, for a portion of the hot-rolled plates, one or both of the following are applied: light rolling before hot-rolled annealing using a finishing mill, or brushing after pickling. Brushing uses silicon carbide brush rollers with nylon bristles and silicon carbide abrasive grains. The elongation (%) of the light rolling before hot-rolled annealing, and the torque (N·m) and rotational speed (rpm) during brushing after pickling are recorded in Tables 2-1 and 2-2.

[0169] steel plate structure

[0170] A sample with a cross-section allowing observation of the rolling direction was cut from the obtained hot-rolled annealed sheet. After embedding, grinding, and etching to reveal the microstructure, the steel sheet microstructure was observed. Based on the photographs of the microstructure, the average grain size was calculated through image analysis. Here, the average grain size is set as the equivalent circle diameter.

[0171] Integral intensity of oxides

[0172] Samples with a thickness of 25×30mm were cut from the obtained hot-rolled annealed sheet. The residual amount of oxide scale on the steel sheet surface was determined by X-ray diffraction. The X-ray incident angle was set to 1 degree for measurement, and the integrated intensity of the (311) plane peak of Fe-Al oxide (iron spinel, FeAl2O4) appearing at 2θ = approximately 36.4 degrees was calculated.

[0173] Fracture resistance in cold rolling

[0174] For the obtained hot-rolled annealed plate, a tandem cold rolling mill was used, with the final thickness set to 0.25 mm and the plate speed at the final stand exit side (excluding the unsteady section near the weld) set to 600 m / min for a total rolling of 8000 m. Cases with more than one fracture were marked as ×, cases without fracture were marked as ○, and cases without fracture and with small load changes in the initial stand were marked as ◎.

[0175] Here, "small load variation" means that when rolling is performed at 600 m / min using a tandem mill, the average value of the rolling load of #1std is set as L. ave When the difference between the maximum and minimum values ​​of the aforementioned rolling load is ΔL, the average value L of the aforementioned rolling load is... ave The ratio of the maximum and minimum values ​​ΔL / L ave ×100 is less than 10%.

[0176] Iron loss W of the final annealed plate 10 / 400

[0177] For the cold-rolled sheets described above, final annealing was performed under the conditions shown in Tables 2-1 and 2-2. The soaking time was set to 10 s. Test pieces measuring 30 mm wide and 280 mm long were cut from the obtained final annealed sheets along the L direction (rolling direction) and the C direction (direction perpendicular to the rolling direction). Iron loss W was measured according to JIS C 2550-1. 10 / 400 .

[0178] The above measurement results are recorded in Tables 2-1 and 2-2. These results show that by controlling the manufacturing conditions of the steel plate within the scope of this invention, it is possible to obtain a hot-rolled annealed sheet for non-oriented electromagnetic steel that combines fracture prevention during cold rolling after hot-rolled annealing with excellent magnetic properties after cold-rolled annealing.

[0179] [Table 1]

[0180] (Example 2)

[0181] The slab manufactured in Example 1, containing all the components shown in Table 1 and with the balance consisting of Fe and unavoidable impurities, was heated in a gas furnace under the conditions shown in Tables 3-1 and 3-2, and then hot-rolled by roughing and finishing to produce a hot-rolled plate with a thickness of 1.8 mm and a width of 1200 mm. The hot-rolled plate was then hot-rolled and annealed, followed by brushing and pickling to obtain a hot-rolled annealed plate. For a portion of the hot-rolled plate, one or both of the following were applied: light rolling before hot-rolled annealing using a finishing mill, or brushing after pickling. Brushing was performed using silicon carbide brush rollers with nylon bristles and silicon carbide abrasive grains. The elongation (%) of the light rolling before hot-rolled annealing, the torque (N·m) and rotational speed (rpm) during brushing before pickling, and the torque (N·m) and rotational speed (rpm) during brushing after pickling are recorded in Tables 3-1 and 3-2.

[0182] steel plate structure

[0183] A sample with a cross-section allowing observation of the rolling direction was cut from the obtained hot-rolled annealed sheet. After embedding, grinding, and etching to reveal the microstructure, the steel sheet microstructure was observed. Based on the photographs of the microstructure, the average grain size was calculated through image analysis. Here, the average grain size is set as the equivalent circle diameter.

[0184] Integral intensity of oxides

[0185] Samples with a thickness of 25×30mm were cut from the obtained hot-rolled annealed sheet. The residual amount of oxide scale on the steel sheet surface was determined by X-ray diffraction. The X-ray incident angle was set to 1 degree for measurement, and the integrated intensity of the (311) plane peak of Fe-Al oxide (iron spinel, FeAl2O4) appearing at 2θ = approximately 36.4 degrees was calculated.

[0186] Fracture resistance in cold rolling

[0187] For the obtained hot-rolled annealed plate, a tandem cold rolling mill was used, with the final thickness set to 0.25 mm and the plate speed at the final stand exit side (excluding the unsteady section near the weld) set to 600 m / min for a total rolling of 8000 m. Cases with more than one fracture were marked as ×, cases without fracture were marked as ○, and cases without fracture and with small load changes in the initial stand were marked as ◎.

[0188] Here, "small load variation" means that when rolling is performed at 600 m / min using a tandem mill, the average value of the rolling load of #1std is set as L. aveWhen the difference between the maximum and minimum values ​​of the aforementioned rolling load is ΔL, the average value L of the aforementioned rolling load is... ave The ratio of the maximum and minimum values ​​ΔL / L ave ×100 is less than 10%.

[0189] Iron loss W of the final annealed plate 10 / 400

[0190] For the cold-rolled sheets described above, final annealing was performed under the conditions shown in Tables 3-1 and 3-2. The soaking time was set to 10 s. Test pieces with a width of 30 mm and a length of 280 mm were cut from the obtained final annealed sheets along the L direction (rolling direction) and the C direction (direction perpendicular to the rolling direction). Iron loss W was determined according to JIS C 2550-1. 10 / 400 .

[0191] The above measurement results are recorded in Tables 3-1 and 3-2. These results show that by controlling the manufacturing conditions of the steel plate within the scope of this invention, it is possible to obtain a hot-rolled annealed sheet for non-oriented electromagnetic steel that combines fracture prevention during cold rolling after hot-rolled annealing with excellent magnetic properties after cold-rolled annealing.

[0192]

Claims

1. A hot-rolled annealed sheet for non-oriented electromagnetic steel, comprising, by mass%, 0.0050% or less of C, 2.0-5.0% of Si, 0.2-2.0% of Mn, 0.030% or less of P, 0.0050% or less of S, 0.25-2.50% of Al, 0.0050% or less of N, 0.0050% or less of O, and one or more of Sn and Sb, totaling 0.01-0.20%, with the balance being Fe and unavoidable impurities. The average grain size of the steel plate in the rolling direction section is 40–250 μm. The integrated intensity of the Fe-Al oxide layer on the surface of the steel plate, as determined by X-ray diffraction, is below 200 cps·degree.

2. The hot-rolled annealed sheet for non-oriented electromagnetic steel sheet according to claim 1, characterized in that, Based on the aforementioned composition, the product also contains, by mass%, one or more components selected from groups A to D below. Group A: Selected from one or more of Ca, Mg, and REM: Total 0.0010–0.0080%; Group B: Selected from one or more of Cr, Mo, Cu, and Ni: Total 0.01–0.60%; Group C: Selected from one or more of Ti, Nb, and V: Total 0.0005–0.0030%; Group D: B: 0.0001~0.0020%.

3. The hot-rolled annealed sheet for non-oriented electromagnetic steel sheet according to claim 1 or 2, characterized in that, Based on the aforementioned composition, the product also contains, by mass%, one or more components selected from groups E to J below. ·Group E: Zn: 0.001~0.010%; Group F: Selected from one or more of Zr, Ta, W, and Se: Total 0.001–0.010%; Group G: Selected from one or more of Ga and Ge: Total 0.0001–0.0200%; • Group H: Selected from one or more of Pb and Bi: Total 0.00005~0.0020%; ·Group I: Co: 0.001~0.100%; ·Group J: As: 0.0005~0.020%.

4. A method for manufacturing hot-rolled annealed sheet for non-oriented electromagnetic steel sheets. It includes: The hot rolling process involves heating and hot rolling a steel billet to produce a hot-rolled steel plate. The steel billet has the following composition by mass%: C: less than 0.0050%, Si: 2.0-5.0%, Mn: 0.2-2.0%, P: less than 0.030%, S: less than 0.0050%, Al: 0.25-2.50%, N: less than 0.0050%, O: less than 0.0050%, and one or more of Sn and Sb: totaling 0.01-0.20%, with the balance consisting of Fe and unavoidable impurities. The hot-rolled steel sheet annealing process involves annealing the hot-rolled steel sheet to produce a hot-rolled annealed sheet. The shot blasting process includes shot blasting the hot-rolled annealed sheet; and The pickling process involves pickling the hot-rolled annealed sheet after shot blasting. In the hot rolling process, the heating temperature of the steel billet is set below 1150℃, the finishing rolling temperature is set below 960℃, and the coiling temperature is set below 700℃. In the hot-rolled sheet annealing process, the annealing temperature is set to above 800℃ and below 1100℃. In the shot blasting process, the hot-rolled annealed plate is subjected to a shot blasting density of 10–40 kg / m³. 2 shot blasting, In the pickling process, the steel plate after shot blasting is pickled under the conditions of hydrochloric acid concentration of 5% or more, pickling temperature of 70°C or more, and pickling time of 10 seconds or more and 120 seconds or less.

5. The method for manufacturing hot-rolled annealed sheet for non-oriented electromagnetic steel sheet according to claim 4, characterized in that, The steel billet, in addition to the aforementioned composition, also contains, by mass percent, one or more components selected from groups A to D below. Group A: Selected from one or more of Ca, Mg, and REM: Total 0.0010–0.0080%; Group B: Selected from one or more of Cr, Mo, Cu, and Ni: Total 0.01–0.60%; Group C: Selected from one or more of Ti, Nb, and V: Total 0.0005–0.0030%; Group D: B: 0.0001~0.0020%.

6. The method for manufacturing hot-rolled annealed sheet for non-oriented electromagnetic steel sheet according to claim 4 or 5, characterized in that, The steel billet, in addition to the aforementioned composition, also contains, by mass percent, one or more components selected from groups E to J below. ·Group E: Zn: 0.001~0.010%; Group F: Selected from one or more of Zr, Ta, W, and Se: Total 0.001–0.010%; Group G: Selected from one or more of Ga and Ge: Total 0.0001–0.0200%; • Group H: Selected from one or more of Pb and Bi: Total 0.00005~0.0020%; ·Group I: Co: 0.001~0.100%; ·Group J: As: 0.0005~0.020%.

7. A method for manufacturing hot-rolled annealed sheet for non-oriented electromagnetic steel sheet according to any one of claims 4 to 6, characterized in that, Before annealing the hot-rolled steel sheet, the hot-rolled steel sheet is subjected to rolling and / or tensile bending processes with an elongation of 0.1 to 10.0%.

8. The method for manufacturing hot-rolled annealed sheet for non-oriented electromagnetic steel sheet according to any one of claims 4 to 7, characterized in that, After the pickling process, the surface and back of the pickled steel plate are brushed and polished.

9. A method for manufacturing a non-oriented electromagnetic steel sheet, wherein, A cold-rolled sheet with a final thickness is produced by performing a single cold rolling or two or more cold rolling processes including intermediate annealing on the hot-rolled annealed sheet obtained in any one of claims 4 to 8, and then annealing the cold-rolled sheet at a homogenization temperature of 700 to 1100°C.

10. A method for manufacturing hot-rolled annealed sheet for non-oriented electromagnetic steel sheets. It includes: The hot rolling process involves heating and hot rolling a steel billet to produce a hot-rolled steel plate. The steel billet has the following composition by mass%: C: less than 0.0050%, Si: 2.0-5.0%, Mn: 0.2-2.0%, P: less than 0.030%, S: less than 0.0050%, Al: 0.25-2.50%, N: less than 0.0050%, O: less than 0.0050%, and one or more of Sn and Sb: totaling 0.01-0.20%, with the balance consisting of Fe and unavoidable impurities. The hot-rolled steel sheet annealing process involves annealing the hot-rolled steel sheet to produce a hot-rolled annealed sheet. The brushing process includes brushing the hot-rolled annealed plate; and The pickling process involves pickling the brushed and polished hot-rolled annealed sheet. In the hot rolling process, the heating temperature of the steel billet is set below 1150℃, the finishing rolling temperature is set below 960℃, and the coiling temperature is set below 700℃. In the hot-rolled sheet annealing process, the annealing temperature is set to above 800℃ and below 1100℃. In the pickling process, the brushed steel plate is pickled under the conditions of hydrochloric acid concentration of 5% or higher, pickling temperature of 70°C or higher, and pickling time of 10 seconds or more and 120 seconds or less.

11. The method for manufacturing hot-rolled annealed sheet for non-oriented electromagnetic steel sheet according to claim 10, characterized in that, The steel billet, in addition to the aforementioned composition, also contains, by mass percent, one or more components selected from groups A to D below. Group A: Selected from one or more of Ca, Mg, and REM: Total 0.0010–0.0080%; Group B: Selected from one or more of Cr, Mo, Cu, and Ni: Total 0.01–0.60%; Group C: Selected from one or more of Ti, Nb, and V: Total 0.0005–0.0030%; Group D: B: 0.0001~0.0020%.

12. The method for manufacturing hot-rolled annealed sheet for non-oriented electromagnetic steel sheet according to claim 10 or 11, characterized in that, The steel billet, in addition to the aforementioned composition, also contains, by mass percent, one or more components selected from groups E to J below. ·Group E: Zn: 0.001~0.010%; Group F: Selected from one or more of Zr, Ta, W, and Se: Total 0.001–0.010%; Group G: Selected from one or more of Ga and Ge: Total 0.0001–0.0200%; • Group H: Selected from one or more of Pb and Bi: Total 0.00005~0.0020%; ·Group I: Co: 0.001~0.100%; ·Group J: As: 0.0005~0.020%.

13. A method for manufacturing hot-rolled annealed sheet for non-oriented electromagnetic steel sheet according to any one of claims 10 to 12, characterized in that, Before annealing the hot-rolled steel sheet, the hot-rolled steel sheet is subjected to rolling and / or tensile bending processes with an elongation of 0.1 to 10.0%.

14. A method for manufacturing hot-rolled annealed sheet for non-oriented electromagnetic steel sheet according to any one of claims 10 to 13, characterized in that, After the pickling process, the surface and back of the pickled steel plate are brushed and polished.

15. A method for manufacturing a non-oriented electromagnetic steel sheet, wherein, A cold-rolled sheet of final thickness is produced by cold rolling the hot-rolled annealed sheet obtained in any one of claims 10 to 14 once or by cold rolling twice or more including intermediate annealing, and then annealing the cold-rolled sheet at a homogenization temperature of 700 to 1100°C.

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