Non-oriented electrical steel sheet having excellent punchability and manufacturing method therefor

Abstract

Disclosed in the present invention is a non-oriented electrical steel sheet having excellent punchability. In addition to Fe and inevitable impurities, the non-oriented electrical steel sheet further contains the following chemical elements in percentage by mass: greater than 0% and less than or equal to 0.004% of C, 1.6-3.4% of Si, 0.05-0.50% of Mn, 0.02-0.10% of P, greater than 0% and less than or equal to 0.50% of Al, 0.0003-0.0040% of Ca, and 0.01-0.20% of Cr, wherein the total of Si and Al is 1.8 to 3.6%. Further disclosed in the present invention is a manufacturing method for the non-oriented electrical steel sheet. The non-oriented electrical steel sheet of the present invention not only has low iron loss and high magnetic induction, but also exhibits excellent punchability.

Description

Non-oriented electrical steel sheet having excellent blanking processability and manufacturing method thereof TECHNICAL FIELD

[0001] The present invention relates to a steel sheet and a manufacturing method thereof, and more particularly, to a non-oriented electrical steel sheet and a manufacturing method thereof. BACKGROUND

[0002] Various motors, compressors, driving motors and the like are major consumers of electric power energy. In order to reduce the electric power consumption of the electric appliances as much as possible, the non-oriented electrical steel sheet used to manufacture the core of the electric appliances needs to have a low iron loss, a high magnetic induction and good blanking processability.

[0003] However, it is difficult to simultaneously consider the iron loss, the magnetic induction and the blanking processability. Generally, by adding a large amount of alloying elements such as Si, Mn and Al into the steel, the iron loss of the non-oriented electrical steel sheet is greatly reduced, but the magnetic induction of the material is also greatly reduced. At the same time, the mechanical properties of the material are also increased, which deteriorates the blanking processability. SUMMARY

[0004] One of the purposes of the present invention is to provide a non-oriented electrical steel sheet having excellent blanking processability, which is obtained by optimizing the chemical composition design of the steel, and has excellent blanking processability on the basis of excellent magnetic properties.

[0005] In order to achieve the above-mentioned purpose, the present invention provides a non-oriented electrical steel sheet having excellent blanking processability, which contains, in addition to Fe and inevitable impurities, the following chemical elements in the mass percentage as follows:

[0006] 0 < C ≤ 0.004%, Si: 1.6-3.4%, Mn: 0.05-0.50%, P: 0.02-0.10%, 0 < Al ≤ 0.50%, Ca: 0.0003-0.0040%, Cr: 0.01-0.20%; wherein the total amount of Si+Al is 1.8-3.6%.

[0007] Preferably, the mass percentage of each chemical element of the non-oriented electrical steel sheet of the present disclosure is as follows:

[0008] 0 < C ≤ 0.004%, Si: 1.6-3.4%, Mn: 0.05-0.50%, P: 0.02-0.10%, 0 < Al ≤ 0.50%, Ca: 0.0003-0.0040%, Cr: 0.01-0.20%; the balance being Fe and inevitable impurities;

[0009] wherein the total amount of Si+Al is 1.8-3.6%.

[0010] Preferably, the non-oriented electrical steel sheet of the present disclosure further contains at least one of the following chemical elements in the mass percentage as follows: 0 < Ge ≤ 0.02%; 0 < Bi ≤ 0.01%; 0 < REM ≤ 0.02%.

[0011] Preferably, the non-oriented electrical steel sheet of the present disclosure further contains at least one of Sn and Sb. In one embodiment, Sn: 0 ~ 0.20%, Sn is preferably 0.02 ~ 0.20%. In one embodiment, Sb: 0 ~ 0.10%, Sb is preferably 0.01 ~ 0.10%. In one embodiment, 0 < Sn + Sb ≤ 0.25%, preferably 0.03 ≤ Sn + Sb ≤ 0.25%.

[0012] Preferably, the inevitable impurities in the non-oriented electrical steel sheet of the present disclosure include S, N and Ti, and S ≤ 0.0030%, N ≤ 0.0030%, Ti ≤ 0.0010%.

[0013] Preferably, the average grain size of the non-oriented electrical steel sheet of the present disclosure is 85 ~ 130 μm.

[0014] Preferably, the thickness of the non-oriented electrical steel sheet of the present disclosure is 0.35 ~ 0.50 mm.

[0015] Preferably, the yield strength Y S of the non-oriented electrical steel sheet of the present disclosure is 280 ~ 400 MPa.

[0016] In the present disclosure, the yield strength Y S of the finished steel sheet has a close relationship with the punching processability. On the one hand, a lower yield strength Y S is not conducive to the punching process, because the material is too soft to form burrs, and the abnormal increase of the shear surface will lead to the reduction of the lamination factor, and the degradation of the electromagnetic performance of the finished steel sheet. On the other hand, a higher yield strength Y S is also not conducive to the punching process, because the material is too hard to damage the die, which will cause the abnormal reduction of the die life, and the abnormal increase of the pull-off surface will generate shear stress. In addition, too high yield strength will also degrade the electromagnetic performance of the finished steel sheet. Based on this, the present disclosure limits the yield strength Y S of the non-oriented electrical steel sheet to 280 ~ 400 MPa.

[0017] Preferably, the iron loss P 1.5 / 200 of the non-oriented electrical steel sheet of the present disclosure is ≤ 11.2 W / kg, and the magnetic induction B 300 is ≥ 1.40 T.

[0018] More preferably, the iron loss P 1.5 / 200 of the non-oriented electrical steel sheet of the present disclosure is 10.0 ~ 11.2 W / kg, and the magnetic induction B 300is 1.40-1.43T.

[0019] More preferably, the performance of the non-oriented electrical steel sheet of the present disclosure satisfies: the iron loss deterioration rate is not greater than 1% within 3 million times of punching; the iron loss deterioration rate is not greater than 2% within 5 million times of punching.

[0020] Another object of the present application is to provide a manufacturing method of a non-oriented electrical steel sheet with excellent punching processability, which obtains a non-oriented electrical steel sheet with good iron loss, magnetic induction and punching processability by optimizing the continuous annealing process.

[0021] In order to achieve the above-mentioned object, the present application provides a method for manufacturing a non-oriented electrical steel sheet, comprising the following steps:

[0022] (1) smelting and casting;

[0023] (2) heating and hot rolling;

[0024] (3) cold rolling after pickling;

[0025] (4) continuous annealing: soaking time is 5-60s, soaking temperature is T=850+20a[Si+Al], wherein the unit of soaking temperature T is ℃, [Si+Al] represents the numerical value before the percentage sign of the total mass percentage of Si and Al, and a represents a texture factor coefficient, wherein a=1.2-3.6.

[0026] In the present application, the soaking temperature of the continuous annealing is related to the total content of chemical components Si and Al and the texture factor coefficient a. The texture factor coefficient a is the ratio of crystal texture (111) / [(100)+(110)+(111)], which can be obtained by detecting the crystal texture of (100), (110), (111) in the finished steel sheet by X-RD (X-ray diffractometer). When the total content of Si and Al is high, a higher soaking temperature is needed to reduce the iron loss of the finished steel sheet; when the texture factor coefficient is large, (111) is easy to generate. Therefore, the soaking temperature needs to be controlled to ensure that the beneficial texture (100), (110) grows rapidly in the high temperature stage after the Curie temperature, so as to improve the punching processability of the material.

[0027] Preferably, in the manufacturing method of the present disclosure, a normalizing step is further included between steps (2) and (3), the normalizing temperature is 850-1050℃, and the atmosphere is hydrogen with a volume fraction of 0-40%+ nitrogen with the balance.

[0028] Preferably, in step (2) of the manufacturing method of the present disclosure, the tapping temperature of the cast blank is 1050-1200℃, the final rolling temperature is 800-1000℃, and the coiling temperature is 500-750℃.

[0029] Preferably, in step (2) of the manufacturing method of the present disclosure, the hot-rolled plate thickness is 1.2-2.8 mm.

[0030] Preferably, in step (1) of the manufacturing method of the present disclosure, calcium treatment is performed during smelting to improve the control effect of inclusions.

[0031] In the manufacturing method of the present disclosure, an insulating coating can also be applied as needed after continuous annealing.

[0032] The non-oriented electrical steel sheet of the present disclosure has the following advantages and beneficial effects:

[0033] The non-oriented electrical steel sheet of the present disclosure not only has a lower iron loss, but also has a higher magnetic induction and excellent blanking processability.

[0034] In some embodiments, the yield strength Y S of the non-oriented electrical steel sheet of the present disclosure is 280-400 MPa, the iron loss P 1.5 / 200 is ≤11.2 W / kg, and the magnetic induction B 300 is ≥1.40 T.

[0035] In some embodiments, the performance of the non-oriented electrical steel sheet of the present disclosure meets the following requirements: the iron loss degradation rate is not greater than 1% within 3 million times of blanking; the iron loss degradation rate is not greater than 2% within 5 million times of blanking.

[0036] The manufacturing method of the non-oriented electrical steel sheet of the present disclosure is simple, easy to control, low in cost, high in precision, and easy to implement. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 shows the relationship between the yield strength Y S and the blanking processability of the non-oriented electrical steel sheet.

[0038] Figure 2 shows the difference in iron loss P 1.5 / 200 degradation effect during the blanking process of the non-oriented electrical steel sheet of Example 1 and the comparative steel sheet of Comparative Example 1.

[0039] Figure 3 shows a schematic diagram of the shearing surface and the broken surface of the non-oriented electrical steel sheet of Example 3 during the shearing and blanking process. DETAILED DESCRIPTION

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0041] In this context, the average grain size is determined in accordance with the Chinese national standard GB T 6394-2017 using the metal average grain size determination method.

[0042] In the present text, the iron loss P 1.5 / 200 refers to the iron loss at a magnetic flux density of 1.5 T and a magnetization frequency of 200 Hz. The iron loss P 1.5 / 200 is determined according to the Chinese national standard GB / T 3658-1990 by means of the Epstein square method.

[0043] In the present text, the magnetic induction B 300 refers to the magnetic induction measured at an applied magnetic field strength of 300 A / m. The magnetic induction B 300 is determined according to the Chinese national standard GB / T 3658-1990 by means of the Epstein square method.

[0044] In the present text, the yield strength Y S is determined according to the Chinese national standard GB / T 228.1-2010.

[0045] In the present text, the texture factor is the ratio of the crystal texture (111) / [(100) + (110) + (111)], which is obtained by detecting the crystal textures (100), (110), (111) in the finished steel plate by means of X-RD (X-ray diffractometer).

[0046] In the non-oriented electrical steel plate of the present disclosure, the design principles of each chemical element are as follows:

[0047] C: In the non-oriented electrical steel plate of the present disclosure, when the content of C element is higher than 0.004%, it will cause magnetic aging and deteriorate the electromagnetic properties of the steel. Therefore, in the non-oriented electrical steel plate of the present disclosure, the mass percentage content of C element is controlled between 0 < C ≤ 0.004%, preferably 0 < C ≤ 0.0039%, more preferably 0.0012 < C ≤ 0.0039%.

[0048] Si: In the non-oriented electrical steel plate of the present disclosure, when the content of Si element is lower than 1.6%, it cannot effectively reduce the iron loss of the steel; when the content of Si element is higher than 3.4%, it will cause a significant reduction in processability. Therefore, in the non-oriented electrical steel plate of the present disclosure, the mass percentage content of Si element is controlled between 1.6-3.4%.

[0049] Mn: In the non-oriented electrical steel plate of the present disclosure, when the content of Mn element is lower than 0.05%, it cannot effectively expand the austenite phase region; when the content of Mn element is higher than 0.5%, it will cause a significant increase in cost. Therefore, in the non-oriented electrical steel plate of the present disclosure, the mass percentage content of Mn element is controlled between 0.05-0.50%.

[0050] P: In the non-oriented electrical steel sheet of the present disclosure, when the content of P element is lower than 0.02%, the proportion of favorable crystal texture cannot be effectively improved; when the content of P element is higher than 0.10%, the cold rolling stability is reduced. Therefore, in the non-oriented electrical steel sheet of the present disclosure, the mass percentage content of P element is controlled between 0.02-0.10%.

[0051] Al: In the non-oriented electrical steel sheet of the present disclosure, when the content of Al element is higher than 0.5%, the proportion of favorable grain texture is significantly reduced, and the magnetic induction of the steel is greatly deteriorated. Therefore, in the non-oriented electrical steel sheet of the present disclosure, the mass percentage content of Al element is controlled between 0

[0052] Ca: In the non-oriented electrical steel sheet of the present disclosure, when the content of Ca element is lower than 0.0003%, it is not conducive to control the harmful inclusions in the steel; when the content of Ca element is higher than 0.004%, the continuous casting stability is reduced. Therefore, in the non-oriented electrical steel sheet of the present disclosure, the mass percentage content of Ca element is controlled between 0.0003-0.0040%.

[0053] Cr: In the non-oriented electrical steel sheet of the present disclosure, when the content of Cr element is lower than 0.01%, it is not conducive to improve the blanking process performance; when the content of Cr element is higher than 0.20%, the proportion of favorable crystal texture is reduced. Therefore, in the non-oriented electrical steel sheet of the present disclosure, the mass percentage content of Cr element is controlled between 0.01-0.20%.

[0054] In addition, in order to achieve balanced improvement of the iron loss, magnetic induction performance and blankable processability of the non-oriented electrical steel sheet, 1.8%≤(Si+Al)≤3.6% is controlled.

[0055] Preferably, the non-oriented electrical steel sheet of the present disclosure further contains at least one of the following chemical elements with a mass percentage content of: 0

[0056] Ge: In the non-oriented electrical steel sheet of the present disclosure, Ge element can significantly improve the proportion of favorable crystal texture. When the content of Ge element is higher than 0.02%, the manufacturing cost is greatly increased. Therefore, in the non-oriented electrical steel sheet of the present disclosure, the mass percentage content of Ge element is controlled to be 0

[0057] Bi: In the non-oriented electrical steel sheet of the present disclosure, Bi element can significantly improve the proportion of favorable crystal texture. When the content of Bi element is higher than 0.01%, the grain size is seriously refined. Therefore, in the non-oriented electrical steel sheet of the present disclosure, the mass percentage content of Bi element is controlled to be 0

[0058] REM: In the non-oriented electrical steel sheet of the present disclosure, REM can improve the cleanliness of the steel and promote grain size growth. When the content of REM elements is higher than 0.02%, it will cause a substantial increase in manufacturing costs. Therefore, in the non-oriented electrical steel sheet of the present disclosure, the mass percentage content of REM elements is controlled to be 0 < REM < 0.02%.

[0059] Preferably, the non-oriented electrical steel sheet of the present disclosure also contains at least one of Sn and Sb, and Sn: 0-0.20%, Sb: 0-0.10%, 0 < Sn + Sb < 0.25%.

[0060] Sn, Sb: In the non-oriented electrical steel sheet of the present disclosure, Sn and Sb elements can promote the growth of favorable crystal texture, promote the increase of magnetic induction and the decrease of iron loss. However, when Sn and Sb elements are added in excess, it will cause grain refinement and abnormal segregation. Therefore, in the non-oriented electrical steel sheet of the present disclosure, the mass percentage content of Sn elements is controlled to be 0-0.20%, the mass percentage content of Sb elements is controlled to be 0-0.10%, and the sum of the mass percentage content of Sn and Sb elements is controlled to be 0 < Sn + Sb < 0.25%.

[0061] In the above technical solution, S, N and Ti are all impurity elements in steel. In the case where the technical conditions permit, in order to obtain steel with better performance and higher quality, the content of impurity elements in steel should be reduced as much as possible, wherein:

[0062] S: In the non-oriented electrical steel sheet of the present disclosure, when the content of S elements is higher than 0.003%, it will significantly increase sulfide inclusions and inhibit grain size growth. Therefore, in the non-oriented electrical steel sheet of the present disclosure, the mass percentage content of S elements is controlled to be S < 0.0030%.

[0063] N: In the non-oriented electrical steel sheet of the present disclosure, when the content of N elements is higher than 0.003%, it will significantly increase nitride inclusions and inhibit grain size growth. Therefore, in the non-oriented electrical steel sheet of the present disclosure, the mass percentage content of N elements is controlled to be N < 0.0030%.

[0064] Ti: In the non-oriented electrical steel sheet of the present disclosure, when the content of Ti elements is higher than 0.001%, it will significantly increase nitride inclusions and inhibit grain size growth. Therefore, in the non-oriented electrical steel sheet of the present disclosure, Ti elements are controlled as impurities, and the content thereof is controlled to be Ti < 0.0010%.

[0065] In one embodiment, in the manufacturing method of the present disclosure, the steelmaking raw material is blast furnace molten iron or high-quality scrap steel, or a combination of blast furnace molten iron and high-quality scrap steel in a certain proportion. In one embodiment, in the manufacturing method of the present disclosure, the steelmaking raw material is blast furnace molten iron or high-quality scrap steel, or a combination of blast furnace molten iron and high-quality scrap steel in a certain proportion.

[0066] In one embodiment, in the manufacturing method of the present disclosure, steelmaking is performed by converter steelmaking with continuous casting, or electric furnace steelmaking with continuous casting.

[0067] The non-oriented electrical steel sheet and the manufacturing method thereof of the present disclosure will be further explained and illustrated in connection with specific examples and the accompanying drawings of the specification, however the explanation and illustration do not constitute undue limitation on the technical solutions of the present disclosure.

[0068] Examples 1-8 and Comparative Examples 1-2

[0069] The non-oriented electrical steel sheets of Examples 1-8 and Comparative Examples 1-2 are prepared by using the following steps:

[0070] (1) Smelting and casting: steelmaking is performed by converter steelmaking with continuous casting. During smelting, calcium treatment is performed ( ) or not performed ( ).

[0071] (2) Heating and hot rolling: the casting blank is heated to a temperature of 1050-1200℃, the final rolling temperature is 800-1000℃, the coiling temperature is 500-750℃, and the hot rolling plate thickness is 1.2-2.8mm; then directly proceed to step (4), or first proceed to step (3), and then proceed to step (4);

[0072] (3) Normalization, holding, slow cooling, and bell furnace annealing: the normalization temperature is 850-1050℃, and the atmosphere is hydrogen with a volume fraction of 0-40% + nitrogen with a volume fraction of 60-100%;

[0073] (4) Cold rolling after pickling: after pickling, cold rolling is performed by using a tandem cold rolling mill or a reciprocating rolling mill; wherein the cold rolling target thickness of the non-oriented electrical steel sheet is controlled to be 0.35-0.50mm;

[0074] (5) Continuous annealing: the soaking time is controlled to be 5-60s, and the soaking temperature is T=850+20a[Si+Al], wherein the unit of the soaking temperature T is ℃, [Si+Al] represents the numerical value before the percentage sign of the total mass percentage of Si and Al, and a represents a texture factor coefficient, and the value range of a is 1.2-3.6.

[0075] Comparative Example 1 and Comparative Example 2 use a conventional continuous annealing process, and the soaking temperature is not designed based on the soaking temperature T=850+20a[Si+Al].

[0076] Table 1-1 and Table 1-2 list the mass percentage of each chemical element in the non-oriented electrical steel sheets of Examples 1-8 and the comparative steels of Comparative Examples 1-2.

[0077] Table 1-1. (wt%, the balance is Fe and other unavoidable impurities except S, N and Ti)

[0078] Table 1-2. (wt%, the balance being Fe and unavoidable impurities other than S, N and Ti)

[0079] Table 2 lists the specific process parameters of the non-oriented electrical steel sheets of Examples 1-8 and the comparative steels of Comparative Examples 1-2.

[0080] Table 2. Note: Texture factor coefficient a is the ratio of crystal texture (111) / [(100)+(110)+(111)], which is obtained by detecting the crystal textures of (100), (110), (111) in the finished steel sheet by X-RD (X-ray diffractometer).

[0081] The non-oriented electrical steel sheets of Examples 1-8 and the comparative steels of Comparative Examples 1-2 were sampled, and the samples of each example and comparative steel sheet were observed, and the relevant properties were tested. The results obtained by observation and relevant property testing are listed in Table 3, and the specific testing methods of the relevant properties are described as follows:

[0082] Grain size testing: Based on Chinese national standard GB T 6394-2017, the metal average grain size determination method was used for testing.

[0083] Iron loss performance testing: Based on Chinese national standard GB / T 3658-1990, the iron loss performance was tested by Epstein square method, the test temperature was 20°C constant temperature test, the sample size was 30mm x 300mm, the target mass was 0.5kg, and the test parameters were P1.5 / 200.

[0084] Magnetic induction performance testing: Based on Chinese national standard GB / T 3658-1990, the iron loss performance was tested by Epstein square method, the test temperature was 20°C constant temperature test, the sample size was 30mm x 300mm, the target mass was 0.5kg, and the test parameters were B 300 .

[0085] Yield strength testing: Based on Chinese national standard GB / T 228.1-2010, the yield strength was tested by machining standard samples, the test temperature was 20°C constant temperature test, the sample tensile test gauge length was 50mm, and the measurement results were shown as the average of 3 times.

[0086] Table 3 lists the observation results and relevant property test results of the non-oriented electrical steel sheets of Examples 1-8 and the comparative steels of Comparative Examples 1-2.

[0087] Table 3.

[0088] As can be seen from Table 3 above, the average grain size of the non-oriented electrical steel sheets of Examples 1-8 is between 85 and 130 μm, the iron loss P 1.5 / 200 is between 10.0 and 11.2 W / kg, the magnetic induction B 300 is between 1.41 and 1.43 T, and the electromagnetic properties thereof are excellent. In addition, the yield strength Y S of Examples 1-8 is between 280 and 400 MPa, and the punching processability thereof is excellent.

[0089] FIG. 1 shows the relationship between the yield strength Y S and the punching processability of the non-oriented electrical steel sheet.

[0090] As shown in FIG. 1, when the yield strength Y S is low, for example, less than 280 MPa, the material of the steel is too soft, and burrs are easily formed. In addition, the abnormal increase of the shear surface leads to a decrease in the lamination factor, and the electromagnetic properties of the finished steel sheet are deteriorated, and thus the punching processability is not good. When the yield strength Y S is high, for example, more than 400 MPa, the material of the steel is too hard, and the die is easily damaged, leading to an abnormal decrease in the die life. In addition, the abnormal increase of the pull-off surface leads to the generation of shear stress, and the electromagnetic properties of the finished steel sheet are deteriorated, and thus the punching processability is not good.

[0091] FIG. 2 shows the difference in the deterioration effect of the iron loss P 1.5 / 200 of the non-oriented electrical steel sheet of Example 1 and the comparative steel sheet of Comparative Example 1 during the punching process.

[0092] As the punching process continues, the punching area of the end portion of the test sample becomes larger and larger, and for each punching surface, the shear surface and the pull-off surface change. As shown in FIG. 2, as the punching process continues, the difference in the deterioration of the iron loss P 1.5 / 200 of Example 1 and Comparative Example 1 becomes more and more obvious.

[0093] The average grain size of the comparative steel sheet of Comparative Example 1 is 135 μm, the yield strength Y S is 265 MPa, the iron loss P 1.5 / 200 is 11.4 W / kg, and the magnetic induction B 300 is 1.36 T, and the performance thereof is obviously worse than that of the examples of the present application.

[0094] The average grain size of the comparative steel sheet of Comparative Example 2 is 82 μm, the yield strength Y S is 420 MPa, the iron loss P 1.5 / 200 is 11.7 W / kg, and the magnetic induction B 300 is 1.38 T, and the performance thereof is obviously worse than that of the examples of the present application.

[0095] Figure 3 shows a schematic diagram of the shearing surface and the tensile fracture surface of the non-oriented electrical steel sheet of Example 3 during shearing and blanking processing.

[0096] As shown in Figure 3, in the sample fracture surface morphology, the proportion of the shearing surface and the tensile fracture surface is relatively balanced, the shearing surface is very flat and smooth, and the boundary between the shearing surface and the tensile fracture surface is obvious, indicating that the residual stress generated by the material during processing is small, and the effect of controlling the iron loss deterioration of the finished product sample is good.

[0097] All publications, patent applications, patents, and other references mentioned in this disclosure are incorporated by reference in their entirety.

[0098] Although the present disclosure has been illustrated and described with reference to certain preferred embodiments thereof, it should be understood by the skilled in the art that the foregoing is a further detailed description of the disclosure and is not intended to limit the disclosure to the specific embodiments described. Various changes in form and detail can be made thereto without departing from the spirit and scope of the disclosure.

Claims

1. A non-oriented electrical steel sheet comprising, in addition to Fe and inevitable impurities, the following chemical elements in mass %: 0 < C < 0.004%, Si: 1.6-3.4%, Mn: 0.05-0.50%, P: 0.02-0.10%, 0 < Al < 0.50%, Ca: 0.0003-0.0040%, Cr: 0.01-0.20%; wherein the total of Si + Al is 1.8-3.6%.

2. The non-oriented electrical steel sheet of claim 1, wherein, The non-oriented electrical steel sheet comprises, in mass %, the following chemical elements: 0 < C < 0.004%, Si: 1.6-3.4%, Mn: 0.05-0.50%, P: 0.02-0.10%, 0 < Al < 0.50%, Ca: 0.0003-0.0040%, Cr: 0.01-0.20%; the balance being Fe and inevitable impurities; wherein the total of Si + Al is 1.8-3.6%.

3. The non-oriented electrical steel sheet according to claim 1 or 2, wherein The non-oriented electrical steel sheet further comprises at least one of the following chemical elements in mass %: 0 < Ge < 0.02%; 0 < Bi < 0.01%; 0 < REM < 0.02%.

4. The non-oriented electrical steel sheet according to claim 1 or 2, wherein The non-oriented electrical steel sheet further comprises at least one of Sn and Sb, and Sn: 0-0.20%, preferably 0.02-0.20%, Sb: 0-0.10%, preferably 0.01-0.10%, 0 < Sn + Sb < 0.25%, preferably 0.03 < Sn + Sb < 0.25%.

5. The non-oriented electrical steel sheet according to claim 1 or 2, wherein The inevitable impurities include S, N and Ti, and S < 0.0030%, N < 0.0030%, Ti < 0.0010%.

6. The non-oriented electrical steel sheet according to claim 1 or 2, wherein The non-oriented electrical steel sheet has an average grain size of 85-130 μm.

7. The non-oriented electrical steel sheet according to claim 1 or 2, wherein The non-oriented electrical steel sheet has a thickness of 0.35-0.50 mm.

8. The non-oriented electrical steel sheet according to claim 1 or 2, wherein The yield strength Y of the non-oriented electrical steel sheet S is 280 to 400 MPa.

9. The non-oriented electrical steel sheet according to claim 1 or 2, wherein The iron loss P of the non-oriented electrical steel sheet 1.5 / 200 ≤ 11.2 W / kg, magnetic induction B 300 ≥ 1.40 T.

10. The non-oriented electrical steel sheet according to claim 1 or 2, wherein The non-oriented electrical steel sheet has a performance that satisfies: iron loss degradation rate is not more than 1% within 3 million times of blanking; iron loss degradation rate is not more than 2% within 5 million times of blanking.

11. A method for manufacturing the non-oriented electrical steel sheet according to any one of claims 1-10, comprising the following steps: (1) smelting and casting: preferably calcium treatment is performed during smelting; (2) heating and hot rolling; (3) cold rolling after pickling; (4) continuous annealing: soaking time is 5-60 s, soaking temperature is T = 850 + 20a [Si + Al], wherein the unit of soaking temperature T is °C, [Si + Al] represents the value before the mass % symbol of Si and Al, and a represents a texture factor coefficient, wherein a = 1.2-3.

6.

12. The method of claim 11, wherein, A normalizing step is further included between steps (2) and (3), and the normalizing temperature is 850-1050 °C, and the atmosphere is 0-40% hydrogen + the balance nitrogen.

13. The method of claim 11, wherein, In step (2), the casting blank has a tapping temperature of 1050-1200 °C, a final rolling temperature of 800-1000 °C, and a coiling temperature of 500-750 °C.

14. The method of claim 11, wherein, In step (2), the hot-rolled sheet has a thickness of 1.2-2.8 mm.

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