Production method for avoiding abnormal full-length magnetic properties of low-temperature oriented silicon steel

Abstract

The application provides a production method for avoiding abnormal full-length magnetic performance of low-temperature oriented silicon steel, comprising collecting information of iron loss of a normalized plate and iron loss of a decarburized plate; comparing the information with a system set alarm range, if the information is within the range, it is normal, otherwise, it is abnormal; after the abnormality, if a thickness detection deviation of the normalized plate exceeds 50 microns, thickness correction is performed, if the thickness detection deviation does not exceed 50 microns, normalized temperature is adjusted according to ΔT1=α×ΔP1, ΔT1 is normalized temperature change, α is a coefficient, and ΔP1 is a difference value between the iron loss detection value and the alarm range; after the abnormality, if a thickness detection deviation of the decarburized plate exceeds 10 microns, thickness correction is performed, if the thickness detection deviation does not exceed 10 microns, if nitrogen content of the decarburized plate is greater than 180ppm, nitrogen content adjustment is performed to be within the range, if the nitrogen content is lower than 180ppm, nitrogen content adjustment is performed to be within the range, if the nitrogen content is higher than 180ppm, decarburized annealing temperature is adjusted according to ΔT2=β×ΔP2+γ×P1; ΔT2 is decarburized annealing temperature change, β and γ are coefficients, ΔP2 is a difference value between the iron loss detection value and the alarm range, and P1 is a corresponding normalized plate iron loss detection value.

Description

TECHNICAL FIELD

[0001] The present application relates to a metal material manufacturing method, in particular to a production method for avoiding abnormal full-length magnetic properties of low-temperature oriented silicon steel. BACKGROUND

[0002] Oriented silicon steel is a kind of soft magnetic functional material, mainly used for manufacturing transformer cores. The manufacturing of oriented silicon steel utilizes the principle of secondary recrystallization, and the general production process is steelmaking, hot rolling, normalizing pickling, cold rolling, decarburization annealing and nitriding, high-temperature annealing, hot stretching and skin pass annealing, etc. The finished product thickness of oriented silicon steel products is generally 0.23mm, 0.27mm and 0.30mm. In recent years, the demand for low-loss oriented silicon steel products has increased sharply. Because thin-gauge oriented silicon steel with a thickness of 0.23mm and below has the advantages of low iron loss and excellent performance, more and more oriented silicon steel manufacturers have begun to develop oriented silicon steel products with a thickness of 0.20mm, 0.18mm or even 0.15mm. Due to the thinning of the strip steel, the secondary recrystallization is not easy to perfect, and the magnetic property abnormality is prone to occur. On the other hand, the current mainstream oriented silicon steel production process is a low-temperature process, i.e. the slab heating temperature is between 1100-1250℃, and AlN, CuS and other inhibitors are used, and the method of forming inhibitors after decarburization and nitriding is needed to obtain the inhibition ability. This production method has high process requirements, narrow process window, and is also prone to full-length magnetic property abnormality. The magnetic property abnormality referred to here means that the finished product does not occur or partially occurs secondary recrystallization phenomenon, and the B8 value (magnetic flux density of silicon steel plate under an excitation magnetic field of 800A / m) is generally lower than 1.85T according to the finished product magnetic property test results.

[0003] The technical solution provided in patent document CN107460292B adjusts the equiaxed crystal ratio of the casting blank, the superheat degree of the continuous casting molten steel, the temperature of nitriding, and other measures to ensure the formation depth and uniformity of the inhibitors, effectively controlling the magnetic property abnormality of the strip steel edge caused by linear crystals and uneven grains.

[0004] The technical solution provided in patent document CN105177444B sets the normalizing temperature by utilizing the relationship between the P1.1 / 50 value of the normalizing steel plate and the steel plate temperature in the high-temperature section of the normalizing heat treatment, so as to control the P1.1 / 50 value of the different Als normalizing coils within the required range, thereby obtaining products with excellent magnetic properties.

[0005] The technical solution provided in patent document CN106834614A adds a magnetic field annealing device to the hot stretching and skin pass annealing line to increase the thin strip recrystallization Goss texture component.

[0006] The technical scheme provided in the patent document CN106755874B adjusts decarburization annealing and nitriding annealing, so that the P1.3 / 50 value and the nitriding amount ΔN of the steel coil material are simultaneously within the limited reasonable range, the magnetic performance of the product with a thickness of not more than 0.30 mm reaches more than 1.92T excellent magnetic performance, and high-end notch grade products can be produced by using the high-quality base material.

[0007] In the technical scheme provided in the patent document CN201811474652, after the component relationship between Als and N in the steel is limited according to the Alr value range, the component smelting is limited, the billet is continuously cast, heated, and subjected to conventional hot rolling, and then two-stage normalizing annealing is performed.

[0008] The document Electrotechnical Steel P519 describes that some patents collectively detect the iron loss of decarburized plates, calculate the size of the primary grain size, and then obtain beneficial magnetic performance.

[0009] In summary, the prior art has the following problems:

[0010] (1) Because the process flow of oriented silicon steel is long, the magnetic performance is influenced by complex factors, even if the process conditions are strictly controlled, the product state still fluctuates between the same furnace and the same batch, and the accumulation of the fluctuation will cause abnormal magnetic performance of the final product.

[0011] (2) Single process adjustment still inevitably has the situation that the adjustment is not in place, so the magnetic performance is still abnormal.

[0012] (3) In order to avoid the full-length magnetic performance abnormality, the oriented silicon steel is sampled and detected before and after each process to monitor the organization, composition and other parameters, which will greatly increase the workload and cause unnecessary material waste. SUMMARY

[0013] The technical problem to be solved by the present application is to overcome the above-mentioned deficiencies of the prior art, and to provide a production method for avoiding the full-length magnetic performance abnormality of low-temperature oriented silicon steel.

[0014] The technical problem to be solved can be implemented by the following technical scheme.

[0015] A production method for avoiding the full-length magnetic performance abnormality of low-temperature oriented silicon steel, characterized in that the method comprises the following processing steps:

[0016] (1) Collecting the iron loss information of the normalizing plate;

[0017] (2) According to the information collected in step (1), the iron loss of the normalizing plate is compared with the normalizing iron loss alarm range set in the system. If it is within the alarm value range, normal production is carried out, otherwise it is determined that the normalizing plate iron loss detection value is abnormal;

[0018] Wherein, after determining the abnormality, if the thickness detection deviation of the normalizing plate exceeds 50 microns, thickness correction is carried out, and if it does not exceed 50 microns, the normalizing temperature is adjusted according to the following formula (a):

[0019] ΔT1 = α × ΔP1; (a)

[0020] In formula (a), ΔT1 is the change of normalizing temperature, α is the coefficient, and the value of α is obtained by fitting production performance and control requirements; ΔP1 is the change of iron loss of the normalizing plate, which is the difference between the iron loss detection value and the alarm range;

[0021] (3) Collecting the iron loss information of the decarburization plate;

[0022] (4) According to the information collected in step (3), the iron loss of the decarburization plate is compared with the decarburization iron loss alarm range set in the system. If it is within the alarm value range, normal production is carried out, otherwise it is determined that the decarburization plate iron loss detection value is abnormal;

[0023] Wherein, after determining the abnormality, if the decarburization plate iron loss detection is determined to be abnormal, first confirm whether the thickness detection deviation of the decarburization plate exceeds 10 microns, if it exceeds, thickness correction is carried out, if it does not exceed, confirm whether the nitrogen content of the decarburization plate is greater than 180ppm, if it is lower than 180ppm, adjust the nitriding amount to be within the range, if it is higher than 180ppm, adjust the decarburization annealing temperature according to the following formula (b):

[0024] ΔT2 = β × ΔP2 + γ × P1; (b)

[0025] In formula (b), ΔT2 is the change of decarburization annealing temperature, β and γ are coefficients, and the values of β and γ are obtained by fitting production performance and control requirements; ΔP2 is the change of iron loss of the decarburization plate, which is the difference between the iron loss detection value and the alarm range; P1 is the corresponding normalizing plate iron loss detection value.

[0026] As a further improvement of the technical solution, comparing the iron loss of the normalizing plate with the normalizing iron loss alarm value set in the system means that the average value of the iron loss of the first 100m of the normalizing plate strip is compared, and then every 10m of the detection average value is compared.

[0027] Also as a further improvement of the technical solution, comparing the iron loss of the decarburization plate with the decarburization plate iron loss alarm value set in the system means that the average value of the iron loss of the first 500m of the decarburization plate strip is compared, and then every 50m of the detection average value is compared.

[0028] As a further improvement of the present technical solution, the normalizing iron loss alarm range and the decarburization iron loss alarm range are alarm thresholds set according to production performance and control requirements.

[0029] As a further improvement of the present technical solution, the detected normalizing plate iron loss and the decarburization plate iron loss are iron losses measured through online detection.

[0030] Preferably, the iron loss detection value refers to an online iron loss value at a detection frequency of 50 Hz and a magnetic induction intensity of 1.0 T.

[0031] Further, when the normalizing plate iron loss detection value is greater than the upper alarm limit, ΔP1 is the difference between the iron loss detection value and the upper alarm limit; and when the normalizing plate iron loss detection value is less than the lower alarm limit, ΔP1 is the difference between the iron loss detection value and the lower alarm limit.

[0032] Further, when the decarburization plate iron loss detection value is greater than the upper alarm limit, ΔP2 is the difference between the iron loss detection value and the upper alarm limit; and when the decarburization plate iron loss detection value is less than the lower alarm limit, ΔP2 is the difference between the iron loss detection value and the lower alarm limit.

[0033] Further, the α value ranges from 100 to 500.

[0034] Further, the β value ranges from 100 to 500, and the γ value is less than 1.

[0035] The concept of the present application is based on the following considerations: the production process of oriented silicon steel is long, and each process realizes corresponding organization regulation. In addition to the purification effect of residual elements, the high-temperature annealing process also realizes the secondary recrystallization of oriented silicon steel. Therefore, from the perspective of avoiding magnetic property abnormalities, whether the oriented silicon steel has magnetic property abnormalities after the completion of the high-temperature annealing process can be judged, and thus measures to avoid magnetic property abnormalities of low-temperature oriented silicon steel should be implemented in the high-temperature annealing process and the previous processes. On the other hand, the production process of oriented silicon steel can be understood as a process in which the iron loss gradually decreases. After research, the present inventor finally found that the iron loss of the steel coil that has perfect secondary recrystallization in the finished product is distributed within a certain range, and the iron loss of the coil that has magnetic property abnormalities is either particularly high or particularly low. Therefore, magnetic property abnormalities can be avoided by adjusting the iron loss within a control range. The inter-process iron loss detection can adopt an online iron loss detection method. Considering the production rhythm and the convenience of equipment installation, online iron loss detection devices can be arranged after normalizing and pickling, based on the fact that the plate surface is clean after normalizing and pickling, and interference is small, so as to measure the normalizing plate iron loss; and the online iron loss detection devices can be arranged after decarburization annealing and nitriding, based on the fact that the plate shape is flat after annealing, and interference is small, so as to measure the decarburization plate iron loss. According to the detection results, the process technology can be adjusted accordingly. In this way, the adjustment purpose is achieved, and excessive process adjustment is avoided.

[0036] The method for avoiding abnormal magnetic properties of low-temperature oriented silicon steel has the following advantages and beneficial effects compared with the prior art:

[0037] (1) The production of the constant-annealed plate and the decarburized plate is facilitated by online detection to obtain the iron loss information, compared with sampling detection, which saves materials, manpower and time, and is particularly suitable for the production rhythm on site.

[0038] (2) The full-length magnetic property abnormality can be effectively avoided by detecting the constant annealing and decarburization annealing processes, the material yield is improved, the quality loss is effectively reduced, and the batch and furnace batch quantity is prevented from being scrapped. DETAILED DESCRIPTION

[0039] The application provides a production method for avoiding abnormal full-length magnetic properties of low-temperature oriented silicon steel, which comprises the following steps:

[0040] (1) collecting the iron loss information of the constant-annealed plate;

[0041] If the iron loss of the constant-annealed plate is compared with the alarm range of the constant-annealed iron loss set in the system, and is within the alarm value range, normal production is carried out, otherwise it is determined that the iron loss detection value of the constant-annealed plate is abnormal, and corresponding adjustment is carried out;

[0042] If it is determined that the iron loss detection value of the constant-annealed plate is abnormal, firstly, it is confirmed whether the thickness detection deviation of the constant-annealed plate exceeds 50 microns, if it exceeds, thickness correction is carried out; wherein the thickness is a factor affecting the iron loss detection of the constant-annealed plate, so the thickness detection deviation is confirmed, the thickness detection on site is carried out by X-ray thickness measurement, and correction (calibration) can be completed by using the conventional means in the field, if it is not exceeded, the constant-annealing temperature is adjusted according to the following formula:

[0043] ΔT1=α×ΔP1;

[0044] Wherein, ΔT1 is the change of the constant-annealing temperature, alpha is the coefficient (the value of alpha can be fitted by production performance and control demand, the value range is 100-500), ΔP1 is the change of the iron loss of the constant-annealed plate, which is the difference between the detection value and the alarm range, that is, if the detection value is greater than the upper limit of the alarm, it is the difference between the detection value and the upper limit of the alarm, if the detection value is less than the lower limit of the alarm, it is the difference between the detection value and the lower limit of the alarm.

[0045] (2) collecting the iron loss information of the decarburized plate;

[0046] If the iron loss of the decarburized plate is compared with the alarm range of the decarburization iron loss set in the system, and is within the alarm value range, normal production is carried out, otherwise it is determined that the iron loss detection value of the decarburized plate is abnormal, and corresponding adjustment is carried out;

[0047] If the decarburization plate iron loss detection is abnormal, first confirm whether the decarburization plate thickness detection deviation exceeds 10 microns, if yes, carry out thickness correction, if no, confirm whether the decarburization plate nitrogen content is greater than 180ppm, if less than 180ppm, adjust the nitriding amount to be within the range, if greater than 180ppm, adjust the decarburization annealing temperature according to the following formula:

[0048] ΔT2=β×ΔP2+γ×P1;

[0049] Wherein, ΔT2 is the decarburization annealing temperature change, β, γ are coefficients (β, γ values can be fitted by production performance and control requirements, β value range 100-500, γ value <1), ΔP2 is the decarburization plate iron loss change, which is the difference between the detection value and the alarm range, that is, if the detection value is greater than the upper limit of the alarm, it is the difference between the detection value and the upper limit of the alarm, if the detection value is less than the lower limit of the alarm, it is the difference between the detection value and the lower limit of the alarm; P1 is the corresponding normalized plate iron loss detection value.

[0050] The normalized plate iron loss is compared with the normalized iron loss alarm value set in the system, which refers to the normalized plate strip head 100m iron loss average, and then every 10m detection average is taken for comparison.

[0051] The decarburization plate iron loss is compared with the decarburization plate iron loss alarm value set in the system, which refers to the decarburization plate strip head 500m iron loss average, and then every 50m detection average is taken for comparison.

[0052] The normalized iron loss alarm range and the decarburization iron loss alarm range are alarm thresholds set according to production performance and control requirements.

[0053] The detected normalized plate iron loss and decarburization plate iron loss are iron losses measured by online detection; the iron loss detection value refers to the online iron loss value under the detection frequency of 50Hz and the magnetic induction intensity of 1.0T.

[0054] The method for avoiding low-temperature oriented silicon steel magnetic property abnormality described in the present application will be further explained and described below in conjunction with specific examples, however, the explanation and description do not constitute undue limitation on the technical solutions of the present application.

[0055] An oriented silicon steel manufacturer has an online iron loss instrument arranged after normalizing and pickling, which can detect the online iron loss of the normalized plate; an online iron loss instrument is arranged after decarburization annealing and nitriding, which can detect the online iron loss of the decarburization plate. The two online iron losses are both iron losses under the detection frequency of 50Hz and the magnetic induction intensity of 1.0T. By collecting the normalized plate and decarburization plate iron loss data and combining with the composition and process requirements, the normalized plate iron loss alarm range and the decarburization plate iron loss alarm range are set, and ΔT1=α×ΔP1, ΔT2=β×ΔP2+γ×P1 are fitted, and the corresponding α, β, γ values.

[0056] At some time, the plant normalizing pickling unit produced 5 rolls of A component oriented silicon steel, see Table 1, No. 1-5, and 4 rolls of B component oriented silicon steel, see Table 2, No. 6-9, which were produced by low temperature process, after steelmaking and hot rolling process, the steel rolls were produced and adjusted in the normalizing pickling unit and decarburization annealing unit as shown in Table 1 and Table 2; the final product was detected for B8 value, and after pickling bottom layer, the secondary recrystallization was observed, the results are shown in Table 1 and Table 2. Among them, the data with underline in the table indicates that no process adjustment is made.

[0057] Table 1:

[0058]

[0059] Table 2:

[0060]

[0061] As shown in Table 1, the iron loss value of No. 1 steel roll after normalizing pickling is within the normalizing plate iron loss alarm range, so normal production is carried out.

[0062] When producing No. 2 steel roll, the iron loss value of 100m strip head is 10.16W / Kg, which is lower than the normalizing plate iron loss alarm value, the thickness deviation is within 100 microns, so the normalizing temperature is adjusted according to ΔT1=α×ΔP1, wherein α=408, ΔP1=-0.04, and ΔT1 is calculated as-16.32℃, so the normalizing temperature is reduced by 16℃ for production, and after the process is stabilized, the average value of 10m iron loss detection is 10.24W / Kg, which is within the normalizing plate iron loss alarm value.

[0063] When producing No. 3 steel roll, the iron loss value of 100m strip head is 10.36W / Kg, which is greater than the normalizing plate iron loss alarm value, the thickness deviation is within 100 microns, so the normalizing temperature is adjusted according to ΔT1=α×ΔP1, wherein α=408, ΔP1=-0.06, and ΔT1 is calculated as 24.48℃, so the normalizing temperature is increased by 24℃ for production, and after the process is stabilized, the average value of 10m iron loss detection is 10.24W / Kg, which is within the normalizing plate iron loss alarm value.

[0064] The process adjusted steel rolls of No. 1, 2 and 3 are detected for iron loss value of decarburization and nitriding plate within the alarm range after cold rolling, decarburization and nitriding, so the decarburization annealing temperature is not adjusted, after high temperature annealing and hot stretching and annealing, the secondary recrystallization is perfect, and the magnetic properties are normal, without full length magnetic property abnormality.

[0065] The normalizing plate iron loss and decarburization plate iron loss of No. 4 and 5 steel rolls are all beyond the control range, the final product secondary recrystallization is not perfect, the product B8 value is lower than 1.85T, and the magnetic property abnormality occurs.

[0066] As shown in Table 2, when producing the steel coil of production serial number 6-9, the iron loss value detected after normalizing and pickling is within the alarm range of the normalizing plate, so normal production is carried out. After cold rolling, decarburization and nitriding, when producing the steel coil of production serial number 6, the iron loss value detected at 500m of the strip head is 2.19W / Kg, which is lower than the alarm value of the decarburized plate, the thickness deviation is within 10 microns, the nitrogen content of the decarburized plate is greater than 180ppm, the thickness and nitriding reasons are excluded, so the decarburization temperature is adjusted according to ΔT2=β×ΔP2+γ×P1, wherein β=435.27, γ=0.17, ΔP1=-0.02, P1=9.62, ΔT2 is calculated as-7.07℃, so the decarburization annealing temperature is reduced by 7℃ for production, and after the process is stable, the average value of the 50m iron loss detection is 2.26W / Kg, which is within the alarm range of the decarburized plate, so no further adjustment is made. When producing the steel coil of production serial number 7, the iron loss value detected at 500m of the strip head is 2.32W / Kg, which is higher than the alarm value of the decarburized plate, the thickness deviation is within 10 microns, the nitrogen content of the decarburized plate is greater than 180ppm, the thickness and nitriding reasons are excluded, so the decarburization temperature is adjusted according to ΔT2=β×ΔP2+γ×P1, wherein β=435.27, γ=0.17, ΔP1=0.01, P1=9.69, ΔT2 is calculated as 6℃, so the decarburization annealing temperature is increased by 6℃ for production, and after the process is stable, the average value of the 50m iron loss detection is 2.25W / Kg, which is within the alarm range of the decarburized plate, so no further adjustment is made. After high temperature annealing and hot tensile leveling annealing of the steel coil of production serial number 6 and 7, the secondary recrystallization is perfect, and the magnetic properties are normal, and no full-length magnetic property abnormality occurs.

[0067] The average iron loss of the decarburized plate of the comparison coil of serial number 8 and 9 is beyond the control range, the secondary recrystallization of the final product is not perfect, the product B8 value is lower than 1.85T, and the magnetic property abnormality occurs.

[0068] The production method for avoiding the magnetic property abnormality of low-temperature oriented silicon steel provided by the present application effectively avoids the occurrence of the magnetic property abnormality by detecting the iron loss of the normalizing plate and the iron loss of the decarburized plate and comparing and controlling them with the alarm range.

[0069] It should be noted that the above-mentioned embodiments are only specific embodiments of the present application. Apparently, the present application is not limited to the above-mentioned embodiments, and similar changes or modifications made on the basis of the disclosure of the present application are directly derived or easily thought of by those skilled in the art, and all should belong to the protection scope of the present application.

Claims

1. A production method for avoiding abnormal full-length magnetic properties of low-temperature oriented silicon steel, characterized by, The method comprises the following processing steps: (1) collecting the iron loss information of the normalizing plate; (2) comparing the iron loss of the normalizing plate with the normalizing iron loss alarm range set in the system according to the information collected in step (1), if it is within the alarm value range, then normal production, otherwise it is determined that the iron loss detection value of the normalizing plate is abnormal; Wherein, after determining the abnormality, if the thickness detection deviation of the normalizing plate exceeds 50 microns, then thickness correction is performed, if it does not exceed 50 microns, then the normalizing temperature is adjusted according to the following formula (a): ΔT1 = α × ΔP1; (a) In formula (a), ΔT1 is the change of the normalizing temperature, α is the coefficient, and the value of α is obtained by fitting the production performance and control requirements; ΔP1 is the change of the iron loss of the normalizing plate, which is the difference between the iron loss detection value and the alarm range; (3) collecting the iron loss information of the decarburization plate; (4) comparing the iron loss of the decarburization plate with the decarburization iron loss alarm range set in the system according to the information collected in step (3), if it is within the alarm value range, then normal production, otherwise it is determined that the iron loss detection value of the decarburization plate is abnormal; Wherein, after determining the abnormality, if the iron loss detection value of the decarburization plate is determined to be abnormal, first confirm whether the thickness detection deviation of the decarburization plate exceeds 10 microns, if it exceeds, then thickness correction is performed, if it does not exceed, then confirm whether the nitrogen content of the decarburization plate is greater than 180ppm, if it is lower than 180ppm, then adjust the nitrogen content to be within the range, if it is higher than 180ppm, then adjust the decarburization annealing temperature according to the following formula (b): ΔT2 = β × ΔP2 + γ × P1; (b) In formula (b), ΔT2 is the change of the decarburization annealing temperature, β and γ are coefficients, and the values of β and γ are obtained by fitting the production performance and control requirements; ΔP2 is the change of the iron loss of the decarburization plate, which is the difference between the iron loss detection value and the alarm range; P1 is the iron loss detection value of the corresponding normalizing plate.

2. The production method of avoiding abnormal full-length magnetic properties of low temperature oriented silicon steel according to claim 1, characterized in that, The comparison of the iron loss of the normalizing plate with the normalizing iron loss alarm value set in the system refers to the average value of the iron loss of the first 100m of the normalizing plate, and then the detection average value every 10m is compared.

3. The production method of avoiding abnormal full-length magnetic properties of cryogenic-oriented silicon steel according to claim 1, characterized by, The comparison of the iron loss of the decarburization plate with the decarburization iron loss alarm value set in the system refers to the average value of the iron loss of the first 500m of the decarburization plate, and then the detection average value every 50m is compared.

4. The production method of avoiding abnormal full-length magnetic properties of cryogenic-oriented silicon steel according to claim 1, characterized by, The normalizing iron loss alarm range and the decarburization iron loss alarm range are alarm thresholds set according to production performance and control requirements.

5. The production method of avoiding abnormal full-length magnetic properties of cryogenic-oriented silicon steel according to claim 1, characterized by, The detected iron loss of the normalizing plate and the decarburization plate is the iron loss measured by online detection.

6. The production method of avoiding abnormal full-length magnetic properties of cryogenic-oriented silicon steel according to claim 1, characterized by, The iron loss detection value refers to the online iron loss value at a detection frequency of 50Hz and a magnetic induction intensity of 1.0T.

7. The production method of avoiding abnormal full-length magnetic properties of cryogenic-oriented silicon steel according to claim 1, characterized by, When the iron loss detection value of the normalizing plate is greater than the upper limit of the alarm, ΔP1 is the difference between the iron loss detection value and the upper limit of the alarm; when the iron loss detection value of the normalizing plate is less than the lower limit of the alarm, ΔP1 is the difference between the iron loss detection value and the lower limit of the alarm.

8. The production method of avoiding abnormal full-length magnetic properties of cryogenic-oriented silicon steel according to claim 1, characterized by, When the iron loss detection value of the decarburization plate is greater than the upper limit of the alarm, ΔP2 is the difference between the iron loss detection value and the upper limit of the alarm; when the iron loss detection value of the decarburization plate is less than the lower limit of the alarm, ΔP2 is the difference between the iron loss detection value and the lower limit of the alarm.

9. The production method of avoiding abnormal full-length magnetic properties of cryogenic-oriented silicon steel according to claim 1, characterized by, The value of α ranges from 100 to 500.

10. The production method of avoiding abnormal full-length magnetic properties of cryogenic-oriented silicon steel according to claim 1, characterized by, The value of β ranges from 100 to 500, and the value of γ is less than 1.

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