Method for reducing oxidation of non-oriented silicon steel normalized plate and normalizing furnace

Abstract

The invention discloses a method for reducing oxidation of a non-oriented silicon steel normalized plate and a normalizing furnace, and the method comprises the following steps: S1, arranging a sealing roller at an inlet / outlet of the normalizing furnace, and controlling a roller gap between an upper roller and a lower roller of the sealing roller; s2, sealing control is conducted on an inlet and an outlet of the normalizing furnace and a furnace area by adopting a height-adjustable sealing curtain and injecting N2; s3, the furnace pressure of the normalizing furnace is gradually reduced from the outlet of the radiant tube cooling section to the inlet of the non-oxidation heating furnace, and the furnace pressure of the normalizing furnace is controlled by taking the inlet furnace of the non-oxidation heating furnace as the furnace pressure control reference furnace pressure; and S4, an analysis instrument is arranged in the normalizing furnace, and the furnace pressure of the normalizing furnace is controlled according to data feedback detected by the analysis instrument. By adjusting the control mode of the furnace pressure of the normalizing furnace, improving the sealing mode between the furnace sections and adding the feedback control of the analysis instrument, the serious oxidation condition in the process of producing the non-oriented silicon steel by the normalizing furnace can be effectively solved.

Description

Technical Field

[0001] This invention relates to the field of normalizing furnace production technology, and more specifically, to a method and a normalizing furnace for reducing oxidation of non-oriented silicon steel normalized plates. Background Technology

[0002] In the production of non-oriented silicon steel in normalizing furnaces, severe internal oxidation frequently occurs on the product surface, affecting subsequent rolling processes and the surface quality of the finished product. The main sections of the normalizing furnace include the non-oxidizing heating furnace, the soaking furnace, and the radiant tube cooling section. The non-oxidizing heating furnace generally uses an open-flame burner direct combustion mode. The combustion products of the combustion air and fuel gas include H2O, CO2, and nitrogen oxides. If the ratio of combustion air to fuel gas is abnormally controlled, residual oxygen may remain. Exhaust gas from the non-oxidizing heating furnace flows back into the subsequent furnace sections (soaking and radiant tube cooling sections), causing severe oxidation of the strip surface and affecting product quality. Due to limitations in existing annealing furnace control methods and furnace section sealing designs, it is difficult to reduce oxidation in the normalizing furnace.

[0003] Chinese Patent Application No. 201210060176.7 discloses a method for producing high-quality silicon steel normalized substrates, including steelmaking, hot rolling, and normalizing steps. In the normalizing step, a normalizing furnace is used. The normalizing furnace, along the strip running direction, sequentially includes a preheating section, a non-oxidizing heating section, a furnace throat, subsequent normalizing treatment sections, and an outlet sealing chamber. The furnace pressure of the normalizing furnace has the following distribution: the furnace pressure is highest in the downstream section adjacent to the furnace throat along the strip running direction; the furnace pressure gradually decreases from the section with the highest pressure towards the furnace inlet; and the furnace pressure gradually decreases from the section with the highest pressure towards the furnace outlet. The method of this invention can successfully prevent the formation of dense oxides during the normalizing process, thereby improving the quality of the silicon steel normalized substrate. This technology features simple subsequent normalization processes and reduced costs, and can be used for large-scale production of high-quality silicon steel normalized substrates. However, the furnace pressure control reference furnace pressure provided by the above technology is small, and the furnace pressure of the downstream section adjacent to the furnace throat is set as the maximum furnace pressure. The furnace pressure difference between the furnace sections before and after the furnace throat is small, and the arrangement and related control of the furnace throat and sealing curtain are not involved.

[0004] In view of the above situation, there is an urgent need to research a new technology that can solve the problem of severe oxidation in the normalizing furnace production of non-oriented silicon steel. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method and normalizing furnace for reducing oxidation of non-oriented silicon steel normalizing plates. By adjusting the furnace pressure control method, improving the sealing method between furnace sections, and adding analytical instrument feedback control, the severe oxidation problem in the normalizing furnace production of non-oriented silicon steel can be effectively solved.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] The first aspect of the present invention provides a method for reducing oxidation of normalized non-oriented silicon steel plates.

[0008] Sealing rollers are arranged at the inlet and outlet of the normalizing furnace, and the roller gap of the sealing rollers is controlled.

[0009] A height-adjustable sealing curtain and injected N2 are used to control the sealing of the normalizing furnace inlet and outlet as well as the furnace area;

[0010] The furnace pressure of the normalizing furnace is controlled by using the furnace pressure at the inlet of the non-oxidizing heating furnace as the control reference furnace pressure, so as to ensure that the furnace pressure of the normalizing furnace gradually decreases from the outlet of the radiant tube cooling section to the inlet of the non-oxidizing heating furnace.

[0011] Analytical instruments are installed inside the normalizing furnace, and the furnace pressure is controlled based on the feedback data from the analytical instruments.

[0012] Preferably, the sealing roller at the inlet of the normalizing furnace is located at the inlet of the non-oxidizing heating furnace, and the sealing roller at the outlet of the normalizing furnace is located at the outlet sealing chamber at the end of the radiant tube cooling section. The lower roller of the sealing roller supports the strip steel, and the upper roller of the sealing roller is driven by a motor.

[0013] The gap between the sealing rollers satisfies: h = h m +k1; where h is the roll gap of the sealing roller, in mm; h m is the maximum thickness of the strip, in mm, and k1 is the roll gap compensation coefficient, 0 < k1 ≤ 5.

[0014] Preferably, the sealing control method for the inlet and outlet of the normalizing furnace and the furnace area is as follows:

[0015] S21, the number of N2 injection points Y0≥1 is set in the sealed chamber at the inlet of the non-oxidizing heating furnace;

[0016] S22, the furnace throat between the non-oxidizing heating furnace and the soaking furnace is isolated and sealed by multiple height-adjustable sealing curtains and multiple N2 injection points;

[0017] S23, multiple N2 injection points are set in both the soaking furnace and the radiant tube cooling section;

[0018] S24, a height-adjustable sealing curtain is used to isolate and seal the isolation section between the soaking furnace and the radiant tube cooling section;

[0019] S25 employs multiple height-adjustable sealing curtains and multiple N2 injection points to isolate and seal the outlet sealing chamber at the end of the radiant tube cooling section.

[0020] Preferably, in step S22:

[0021] The lifting height f1 of the sealing curtain installed in the furnace throat satisfies: f1 = h m +k2, where f1 is the lifting height of the sealing curtain in mm, h m is the maximum thickness of the strip steel, in mm; k2 is the compensation coefficient of the furnace throat sealing curtain, 0 < k2 ≤ 10;

[0022] The number of sealing curtains in the furnace throat is X1≥2, and an N2 injection point is arranged between adjacent sealing curtains. The number of N2 injection points in the furnace throat is Y1=X1-1.

[0023] Preferably, in step S23:

[0024] The number of N2 injection points Y2 in the soaking furnace is equal to the number of furnace zones in the soaking furnace;

[0025] The number of N2 injection points in the radiant tube cooling section Y3 is ≥ 1;

[0026] The N2 injection rate of the soaking furnace satisfies the following: the dew point rise slope of the soaking furnace is k5 = ΔT / Δt, with the unit being ℃ / h. When k5 ≥ 5, the N2 injection rate of the soaking furnace is increased by 10% based on the set value.

[0027] The N2 injection amount of the radiant tube cooling section satisfies the following: the dew point rise slope of the radiant tube cooling section is k6 = ΔT / Δt, with the unit being ℃ / h. When k6 ≥ 5, the N2 injection amount of the radiant tube cooling section is increased by 10% based on the set value.

[0028] Preferably, in step S24, the number of sealing curtains in the isolation section X2≥1, and the lifting height f2 of the sealing curtains satisfies: f2=h m +k3, where f2 is the lifting height of the sealing curtain in mm, h m K represents the maximum thickness of the strip steel in mm, and k3 is the compensation coefficient of the sealing curtain of the isolation section, where 0 < k3 ≤ 10.

[0029] Preferably, in step S25:

[0030] The number of sealing curtains in the outlet sealing chamber is X3≥2, and an N2 injection point is arranged between adjacent sealing curtains. The number of N2 injection points in the outlet sealing chamber is Y4=X3-1.

[0031] The lifting height f3 of the sealing curtain installed in the outlet sealing chamber satisfies: f2 = h m +k4, where f3 is the lifting height of the sealing curtain in mm, h m K is the maximum thickness of the strip steel in mm, and k4 is the compensation coefficient of the sealing curtain of the outlet sealing chamber, where 0 < k4 ≤ 10.

[0032] Preferably, the furnace pressure control process of the normalizing furnace is as follows:

[0033] S31, using the inlet furnace pressure of the non-oxidizing heating furnace as the control reference furnace pressure, the furnace pressure of the non-oxidizing heating furnace is adjusted and controlled by adjusting the speed of the exhaust fan of the normalizing furnace and the opening of the baffle.

[0034] S32, the furnace pressure difference between the inlet of the soaking furnace and the outlet of the non-oxidizing heating furnace is controlled by adjusting the amount of N2 injected into the furnace throat and the soaking furnace;

[0035] S33, by adjusting the N2 injection amount in each furnace zone of the soaking furnace, the furnace pressure gradient of the soaking furnace is controlled to control the atmosphere of the soaking furnace to flow from the outlet to the inlet;

[0036] S34, the flow direction of the atmosphere in the normalizing furnace is from the outlet of the radiant tube cooling section to the inlet of the non-oxidizing heating furnace. The furnace pressure at the outlet of the radiant tube cooling section is the highest furnace pressure point. The furnace pressure of the normalizing furnace gradually decreases from the outlet of the radiant tube cooling section to the inlet of the non-oxidizing heating furnace.

[0037] Preferably, in step S31, the inlet furnace pressure P1 of the non-oxidizing heating furnace satisfies: P1=26+k7, where P1 is the inlet furnace pressure of the non-oxidizing heating furnace in Pa, and k7 is the inlet furnace pressure compensation coefficient, 0≤k7≤30;

[0038] In step S32, the furnace pressure difference δP1 between the inlet of the soaking furnace and the outlet of the non-oxidizing heating furnace satisfies: δP1=P3-P2≥15+k8, where δP1 is the furnace pressure difference between the inlet of the soaking furnace and the outlet of the non-oxidizing heating furnace, in Pa; P2 is the furnace pressure at the outlet of the non-oxidizing heating furnace, in Pa; P3 is the furnace pressure at the inlet of the soaking furnace, in Pa; and k8 is the furnace throat pressure compensation coefficient, 0≤k8≤50.

[0039] In step S33, the furnace pressure difference δP2 between the outlet and inlet of the soaking furnace satisfies: δP2=P4-P3=5+k9, where δP2 is the furnace pressure difference between the outlet and inlet of the soaking furnace, in Pa; P4 is the furnace pressure at the outlet of the soaking furnace, in Pa; and k9 is the furnace pressure compensation coefficient of the soaking furnace, 0≤k9≤20.

[0040] In step S34, the furnace pressure difference δP3 between the outlet of the radiant tube cooling section and the outlet of the soaking furnace satisfies: δP3=P5-P4=1+k 10 In the formula, δP3 is the furnace pressure difference between the outlet of the radiant tube cooling section and the outlet of the soaking furnace, in Pa; P5 is the furnace pressure at the outlet of the radiant tube cooling section, in Pa, kJ / m³. 10 k is the furnace pressure compensation coefficient for radiant tube furnaces, 0≤k 10 ≤10.

[0041] Preferably, the process of controlling the furnace pressure of the normalizing furnace based on the feedback of the analytical instrument detection data is as follows:

[0042] S41, an oxygen analyzer is installed at the outlet of the non-oxidizing heating furnace of the normalizing furnace, and a CO analyzer is installed at the inlet of the soaking furnace.

[0043] S42, the oxygen content at the outlet of the non-oxidizing heating furnace is detected by an oxygen analyzer. When the oxygen analyzer detects an increase of 0.1% in the O2 content, the furnace pressure difference δP1 between the inlet of the soaking furnace and the outlet of the non-oxidizing heating furnace is made to be greater than 40 Pa by adjusting the N2 injection amount of the furnace throat and the soaking furnace.

[0044] S43, the CO content at the inlet of the soaking furnace is detected by a CO analyzer. When the CO content detected by the CO analyzer increases by 0.1%, the N2 injection rate of the soaking furnace and the radiant tube cooling section is adjusted to make the furnace pressure difference δP2 between the outlet and inlet of the soaking furnace > 10 Pa.

[0045] A second aspect of the present invention provides a normalizing furnace for reducing oxidation of non-oriented silicon steel normalizing plates, comprising, in sequence, an oxidation-free heating furnace, a furnace throat, a soaking furnace, an isolation section, and a radiant tube cooling section.

[0046] Sealing rollers are respectively installed at the inlet of the non-oxidizing heating furnace and at the outlet of the radiant tube cooling section; the inlet of the non-oxidizing heating furnace is provided with an inlet sealing chamber; the end of the radiant tube cooling section is provided with an outlet sealing chamber;

[0047] The inlet sealing chamber, soaking furnace, and radiant tube cooling section of the non-oxidizing heating furnace are isolated and sealed by injecting N2.

[0048] The isolation section is sealed using a height-adjustable sealing curtain;

[0049] The furnace throat and the outlet sealing chamber at the end of the radiant tube cooling section are isolated and sealed by multiple height-adjustable sealing curtains and multiple N2 injection points, with an N2 injection point arranged between adjacent sealing curtains.

[0050] An oxygen analyzer is installed at the outlet of the non-oxidizing heating furnace, and a CO analyzer is installed at the inlet of the homogenizing furnace.

[0051] Preferably, the inlet sealing chamber of the non-oxidizing heating furnace is provided with at least one N2 injection point;

[0052] The homogenizing furnace is equipped with multiple N2 injection points, and each furnace zone of the homogenizing furnace is equipped with one N2 injection point. The number of N2 injection points is equal to the number of furnace zones of the homogenizing furnace.

[0053] The radiant tube cooling section is provided with at least one N2 injection point.

[0054] Preferably, the isolation section is provided with at least one height-adjustable sealing curtain;

[0055] The number of sealing curtains arranged in the furnace throat is ≥2, and the number of N2 injection points in the furnace throat is one less than the number of sealing curtains arranged.

[0056] The number of sealing curtains arranged in the outlet sealing chamber is ≥2, and the number of N2 injection points in the outlet sealing chamber is one less than the number of sealing curtains arranged.

[0057] Preferably, both the soaking furnace and the radiant tube cooling section are equipped with dew point meters.

[0058] The present invention provides a method and normalizing furnace for reducing oxidation of non-oriented silicon steel normalized plates, which have the following beneficial effects:

[0059] 1. The furnace pressure control benchmark furnace pressure strategy of this invention can prevent atmospheric intake into the furnace and cause strip steel oxidation; the furnace pressure at the outlet of the radiant tube is used as the highest furnace pressure control point, the furnace pressure difference before and after the furnace throat is large, the backflow of exhaust gas from the non-oxidizing heating furnace to the rear furnace section is small, and the furnace pressure difference is used to control the nitrogen injection in the furnace section, improve the control method of the furnace throat and sealing curtain, and control the furnace pressure through the feedback of the analysis instrument data. The furnace atmosphere control method is precise, the furnace pressure and furnace pressure gradient control of each section are stable, the backflow of exhaust gas from the rear furnace section of the non-oxidizing heating furnace is small, the oxidation degree of the product is very light, and the surface quality is excellent.

[0060] 2. The normalizing furnace atmosphere control of the present invention is stable, the furnace pressure gradient of each section is maintained within the set range, the dew point of the soaking furnace and the radiant tube cooling section is stable, effectively reducing the oxidation of the normalizing plate, and no serious product oxidation has occurred. Attached Figure Description

[0061] Figure 1 This is a furnace pressure distribution diagram of the normalizing furnace in the method for reducing oxidation of non-oriented silicon steel normalizing plates according to the present invention;

[0062] In the diagram, 1 is the non-oxidizing heating furnace; 2 is the furnace throat; 3 is the soaking furnace; 4 is the isolation section; 5 is the radiant tube cooling section; 6 is the outlet sealing chamber; 7 is the inlet sealing chamber; 8 is the sealing roller; and 9 is the sealing curtain. Detailed Implementation

[0063] To better understand the above-mentioned technical solutions of the present invention, the technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0064] Because existing technologies often result in severe surface oxidation of non-oriented silicon steel produced in normalizing furnaces, this invention employs a high furnace pressure control benchmark strategy to prevent atmospheric intake into the furnace and subsequent strip oxidation. The furnace pressure at the radiant tube outlet is used as the maximum furnace pressure control point, resulting in a large pressure difference before and after the furnace throat. This pressure difference is used to control nitrogen injection in the furnace section, and the furnace pressure is further controlled via instrument data feedback. This precise furnace atmosphere control ensures stable control of furnace pressure and pressure gradient in each section, minimizes backflow of exhaust gas from the non-oxidizing heating section, and results in very low oxidation levels and excellent surface quality in the product. Non-oriented silicon steel produced using this invention effectively reduces surface oxidation in normalizing furnaces and can be widely used in normalizing furnaces for hot-rolled strip steel.

[0065] Combination Figure 1 As shown, the present invention provides a method for reducing oxidation of normalized non-oriented silicon steel plates, specifically achieved through the following measures:

[0066] (1) A sealing roller 8 is arranged at the inlet and outlet of the normalizing furnace, and the roller gap of the sealing roller 8 is controlled.

[0067] Requirements for the arrangement and gap control of sealing rollers 8: During the normalizing process, the strip is rotated by the furnace rollers. The sealing roller 8 at the inlet of the normalizing furnace is located at the inlet of the non-oxidizing heating furnace 1, and the sealing roller 8 at the outlet of the normalizing furnace is located at the outlet sealing chamber 6 at the end of the radiant tube cooling section 5. The lower roller of the sealing roller 8 supports the strip, and the upper roller of the sealing roller 8 is driven by a motor. To reduce the entry of atmospheric air into the non-oxidizing heating furnace 1 and the radiant tube cooling section 5, the gap of the sealing roller 8 must satisfy: h = h m +k1; where h is the roll gap of the sealing roller 8, in mm; h m is the maximum thickness of the strip, in mm, and k1 is the roll gap compensation coefficient, 0 < k1 ≤ 5.

[0068] (2) A height-adjustable sealing curtain 9 and N2 injection are used to control the sealing of the normalizing furnace inlet and outlet as well as the furnace area;

[0069] This measure addresses the sealing control requirements for the inlet and outlet of the normalizing furnace, as well as the furnace area and adjacent sections. It mainly includes control requirements for: the inlet sealing chamber (7), the furnace throat (2), the soaking furnace (3), the isolation section (4), the radiant tube cooling section (5), and the outlet sealing chamber (6). The specific sealing control methods for the normalizing furnace inlet and outlet, and the furnace area are as follows:

[0070] S21, the number of N2 injection points Y0≥1 is set in the inlet sealing chamber 7 of the non-oxidizing heating furnace 1;

[0071] S22, the furnace throat 2 between the non-oxidizing heating furnace 1 and the soaking furnace 3 is isolated and sealed by multiple height-adjustable sealing curtains 9 and multiple N2 injection points;

[0072] The throat 2 is located between the non-oxidizing furnace 1 and the soaking furnace 3. To reduce the backflow of exhaust gas from the non-oxidizing furnace into the soaking furnace 3, a multi-height adjustable sealing curtain 9 and multiple N2 injection points are used for isolation and sealing. The lifting height f1 of the sealing curtain 9 in the throat 2 section is controlled by an encoder, and the lifting height f1 of the sealing curtain 9 satisfies: f1 = h m +k2, where f1 is the lifting height of the sealing curtain 9, in mm, h m Where is the maximum thickness of the strip steel in mm, and k2 is the compensation coefficient of the furnace throat sealing curtain, 0 < k2 ≤ 10. The number of sealing curtains 9 arranged in the furnace throat 2 is X1 ≥ 2, and an N2 injection point is arranged between adjacent sealing curtains 9. The number of N2 injection points in the furnace throat 2 is Y1 = X1 - 1.

[0073] S23, multiple N2 injection points are set in both the soaking furnace 3 and the radiant tube cooling section 5;

[0074] This process involves controlling N2 in the furnace area. In the normalizing furnace area, N2 injection points are arranged in the furnace section to control the furnace pressure and dew point. These mainly include: the soaking furnace 3 and the radiant tube cooling section 5.

[0075] The number of N2 injection points Y2 in the soaking furnace 3 is equal to the number of furnace zones in the soaking furnace 3, that is, each furnace zone of the soaking furnace 3 is equipped with one N2 injection point.

[0076] The number of 5N2 injection points in the radiant tube cooling section, Y3, is ≥ 1.

[0077] The dew point rise slope is ΔT / Δt, in °C / h; the dew point rise slopes of the soaking furnace 3 and the radiant tube cooling section 5 are represented by k5 and k6, respectively. The N2 injection rate of the soaking furnace 3 satisfies: the dew point rise slope k5 of the soaking furnace 3 = ΔT / Δt, in °C / h. When k5 ≥ 5, the N2 injection rate of the soaking furnace 3 increases by 10% from the set value. The N2 injection rate of the radiant tube cooling section 5 satisfies: the dew point rise slope k6 of the radiant tube cooling section 5 = ΔT / Δt, in °C / h. When k6 ≥ 5, the N2 injection rate of the radiant tube cooling section 5 increases by 10% from the set value.

[0078] S24, the isolation section 4 between the soaking furnace 3 and the radiant tube cooling section 5 is sealed with a height-adjustable sealing curtain 9;

[0079] The soaking furnace 3 and the radiant tube cooling section 5 form an isolation section 4, which is isolated and sealed by a height-adjustable sealing curtain 9; the number of sealing curtains 9 arranged in the isolation section 4 is X2≥1; the isolation section 4 also uses an encoder to control the lifting height of the sealing curtain 9, and the lifting height f2 of the sealing curtain 9 satisfies: f2=h m +k3, where f2 is the lifting height of the sealing curtain 9, in mm, h mK represents the maximum thickness of the strip steel in mm, and k3 is the compensation coefficient of the sealing curtain of the isolation section, where 0 < k3 ≤ 10.

[0080] S25, the outlet sealing chamber 6 at the end of the radiant tube cooling section 5 is sealed by multiple height-adjustable sealing curtains 9 and multiple N2 injection points.

[0081] The outlet sealing chamber 6 at the end of the radiant tube cooling section 5 is designed with multiple sealing curtains 9 and N2 injection points for isolation and sealing. The number of sealing curtains 9 in the outlet sealing chamber 6 is X3≥2, and an N2 injection point is arranged between adjacent sealing curtains 9. The number of N2 injection points in the outlet sealing chamber 6 is Y4=X3-1. The outlet sealing chamber 6 also uses an encoder to control the lifting height of the sealing curtains 9. The lifting height f3 of the sealing curtains 9 in the outlet sealing chamber 6 satisfies: f2=h m +k4, where f3 is the lifting height of the sealing curtain 9 in mm, h m K is the maximum thickness of the strip steel in mm, and k4 is the compensation coefficient of the sealing curtain of the outlet sealing chamber, where 0 < k4 ≤ 10.

[0082] (3) The furnace pressure of the normalizing furnace is controlled by taking the furnace pressure at the inlet of the non-oxidizing heating furnace 1 as the control reference furnace pressure, so as to ensure that the furnace pressure of the normalizing furnace gradually decreases from the outlet of the radiant tube cooling section 5 to the inlet of the non-oxidizing heating furnace 1.

[0083] This measure specifies the pressure control requirements for the normalizing furnace. Specifically, the inlet pressure of the non-oxidizing heating furnace 1 is P1 (Pa); the outlet pressure of the non-oxidizing heating furnace 1 is P2 (Pa); the inlet pressure of the soaking furnace 3 is P3 (Pa); the outlet pressure of the soaking furnace 3 is P4 (Pa); and the outlet pressure of the radiant tube cooling section 5 is P5 (Pa). The detailed process is as follows:

[0084] S31, using the inlet furnace pressure of the non-oxidizing heating furnace 1 as the control reference furnace pressure, the furnace pressure of the non-oxidizing heating furnace 1 is adjusted and controlled by adjusting the speed of the exhaust gas fan of the normalizing furnace and the opening of the baffle.

[0085] The inlet furnace pressure P1 of the non-oxidizing heating furnace 1 is selected as the control reference furnace pressure of the normalizing furnace. The furnace pressure of the non-oxidizing heating furnace 1 is adjusted and controlled by adjusting the speed of the exhaust fan and the opening of the damper of the normalizing furnace. A large furnace pressure control method is adopted to prevent air from being sucked into the furnace through the gap of the inlet sealing roller 8 due to atmospheric fluctuations in the normalizing furnace. The inlet furnace pressure P1 of the non-oxidizing heating furnace 1 satisfies: P1=26+k7, where P1 is the inlet furnace pressure of the non-oxidizing heating furnace 1 in Pa, and k7 is the inlet furnace pressure compensation coefficient, 0≤k7≤30.

[0086] S32, the furnace pressure difference between the inlet of the homogenizing furnace 3 and the outlet of the non-oxidizing heating furnace 1 is controlled by adjusting the N2 injection amount of the furnace throat 2 and the homogenizing furnace 3;

[0087] To minimize the backflow of exhaust gas from the non-oxidizing furnace 1 from the furnace throat 2 to the soaking furnace 3, the furnace pressure difference δP1 between the inlet of the soaking furnace 3 and the outlet of the non-oxidizing furnace 1 is controlled with a large value to create a large gradient atmosphere. δP1 is automatically controlled by adjusting the N2 injection rate of the furnace throat 2 and the soaking furnace 3. The furnace pressure difference δP1 between the inlet of the soaking furnace 3 and the outlet of the non-oxidizing furnace 1 satisfies: δP1=P3-P2≥15+k8, where δP1 is the furnace pressure difference between the inlet of the soaking furnace 3 and the outlet of the non-oxidizing furnace 1, in Pa; P2 is the furnace pressure at the outlet of the non-oxidizing furnace 1, in Pa; P3 is the furnace pressure at the inlet of the soaking furnace 3, in Pa; and k8 is the furnace throat pressure compensation coefficient, 0≤k8≤50.

[0088] S33, by adjusting the N2 injection amount in each furnace zone of the soaking furnace 3, the furnace pressure gradient of the soaking furnace 3 is controlled to control the atmosphere of the soaking furnace 3 to flow from the outlet to the inlet;

[0089] The soaking furnace 3 has M furnace zones, each with one N2 injection point, which can be used to adjust the furnace pressure gradient and control the atmosphere flow from the outlet to the inlet. The furnace pressure difference δP2 between the outlet and inlet of the soaking furnace 3 satisfies: δP2=P4-P3=5+k9, where δP2 is the furnace pressure difference between the outlet and inlet of the soaking furnace 3, in Pa; P4 is the furnace pressure at the outlet of the soaking furnace 3, in Pa; P3 is the furnace pressure at the inlet of the soaking furnace 3, in Pa; and k9 is the furnace pressure compensation coefficient, 0≤k9≤20.

[0090] S34, the atmosphere flow direction in the normalizing furnace is from the outlet of the radiant tube cooling section 5 to the inlet of the non-oxidizing heating furnace 1. The furnace pressure at the outlet of the radiant tube cooling section 5 is the highest furnace pressure point. The furnace pressure of the normalizing furnace gradually decreases from the outlet of the radiant tube cooling section 5 to the inlet of the non-oxidizing heating furnace 1 (see...). Figure 1 (As shown).

[0091] The atmosphere flow within the normalizing furnace is from the outlet of the radiant tube cooling section 5 to the inlet of the non-oxidizing heating furnace 1. The furnace pressure at the outlet of the radiant tube cooling section 5 is considered the highest furnace pressure point. The furnace pressure gradually decreases from the outlet of the radiant tube cooling section 5 to the inlet of the non-oxidizing heating furnace 1. The furnace pressure difference δP3 between the outlet of the radiant tube cooling section 5 and the outlet of the soaking furnace 3 satisfies: δP3=P5-P4=1+k 10 In the formula, δP3 is the furnace pressure difference between the outlet of the radiant tube cooling section 5 and the outlet of the soaking furnace 3, in Pa; P5 is the furnace pressure at the outlet of the radiant tube cooling section 5, in Pa, kJ. 10 k is the furnace pressure compensation coefficient for radiant tube furnaces, 0≤k 10 ≤10.

[0092] (4) Arrange analytical instruments in the normalizing furnace and control the furnace pressure based on the feedback of the analytical instrument detection data.

[0093] This measure uses the feedback from analytical instrument readings to further control the furnace pressure of the normalizing furnace. The specific process is as follows:

[0094] S41, an oxygen analyzer is installed at the outlet of the non-oxidizing heating furnace 1 of the normalizing furnace, and a CO analyzer is installed at the inlet of the soaking furnace 3.

[0095] This step involves arranging analytical instruments inside the normalizing furnace. The furnace pressure regulator can be controlled based on the oxygen content feedback from the non-oxidizing heating furnace 1. Therefore, an oxygen analyzer is arranged at the outlet of the non-oxidizing heating furnace 1 in the normalizing furnace. The degree of backflow of exhaust gas from the non-oxidizing heating furnace 1 can also be determined based on the CO content at the inlet of the soaking furnace 3. Therefore, a CO analyzer is arranged at the inlet of the soaking furnace 3.

[0096] S42, the oxygen content at the outlet of the non-oxidizing heating furnace 1 is detected by an oxygen analyzer. When the O2 content detected by the oxygen analyzer increases by 0.1%, the N2 injection amount of the furnace throat 2 and the soaking furnace 3 is adjusted to make the furnace pressure difference δP1 between the inlet of the soaking furnace 3 and the outlet of the non-oxidizing heating furnace 1 > 40 Pa.

[0097] According to step S41, the oxygen analyzer installed at the outlet of the non-oxidizing heating furnace 1 will detect the oxygen content at the outlet of the non-oxidizing heating furnace 1 in real time. When the O2 content detected by the oxygen analyzer increases by 0.1%, the N2 injection amount of the furnace throat 2 and the soaking furnace 3 will be adjusted so that the furnace pressure difference δP1 between the inlet of the soaking furnace 3 and the outlet of the non-oxidizing heating furnace 1 is greater than 40 Pa.

[0098] S43, the CO content at the inlet of the soaking furnace 3 is detected by a CO analyzer. When the CO content detected by the CO analyzer increases by 0.1%, the N2 injection rate of the soaking furnace 3 and the radiant tube cooling section 5 is adjusted to make the furnace pressure difference δP2 between the outlet and inlet of the soaking furnace 3 > 10 Pa.

[0099] In this step, the homogenizing furnace 3 adopts point heating. According to step S41, the CO content at the inlet of the homogenizing furnace 3 is detected in real time by a CO analyzer placed at the inlet of the homogenizing furnace 3 (the CO content at the inlet of the homogenizing furnace 3 can characterize the degree of backflow of exhaust gas from the non-oxidizing heating furnace 1). When the CO content detected by the CO analyzer increases by 0.1%, the N2 injection amount of the homogenizing furnace 3 and the radiant tube cooling section 5 is adjusted to make the furnace pressure difference δP2 between the outlet and inlet of the homogenizing furnace 3 > 10 Pa.

[0100] Combination Figure 1As shown, the present invention also provides a normalizing furnace for reducing oxidation of non-oriented silicon steel normalizing plates, comprising a non-oxidizing heating furnace 1, a furnace throat 2, a soaking furnace 3, an isolation section 4, and a radiant tube cooling section 5 arranged sequentially. Sealing rollers 8 are respectively installed at the inlet of the non-oxidizing heating furnace 1 and the outlet of the radiant tube cooling section 5; an inlet sealing chamber 7 is provided at the inlet of the non-oxidizing heating furnace 1; and an outlet sealing chamber 6 is provided at the end of the radiant tube cooling section 5. The inlet sealing chamber 7 of the non-oxidizing heating furnace 1, the soaking furnace 3, and the radiant tube cooling section 5 are isolated and sealed by injecting N2. The isolation section 4 is isolated and sealed by a height-adjustable sealing curtain 9. The outlet sealing chamber 6 at the end of the furnace throat 2 and the radiant tube cooling section 5 is isolated and sealed by multiple height-adjustable sealing curtains 9 and multiple N2 injection points, with one N2 injection point arranged between adjacent sealing curtains 9. An oxygen analyzer is arranged at the outlet of the non-oxidizing heating furnace 1, and a CO analyzer is arranged at the inlet of the soaking furnace 3.

[0101] Combination Figure 1 As shown, the inlet sealing chamber 7 of the non-oxidizing heating furnace 1 is equipped with at least one N2 injection point. Multiple N2 injection points are arranged within the soaking furnace 3, with one N2 injection point per furnace zone. The number of N2 injection points equals the number of furnace zones in the soaking furnace 3. The radiant tube cooling section 5 is equipped with at least one N2 injection point.

[0102] Combination Figure 1 As shown, the isolation section 4 is equipped with at least one height-adjustable sealing curtain 9. The number of sealing curtains 9 within the furnace throat 2 is ≥2, and the number of N2 injection points within the furnace throat 2 is one less than the number of sealing curtains 9. The number of sealing curtains 9 within the outlet sealing chamber 6 is ≥2, and the number of N2 injection points within the outlet sealing chamber 6 is one less than the number of sealing curtains 9. The lifting height of the aforementioned sealing curtains 9 can be adjusted and controlled by a corresponding encoder.

[0103] Combination Figure 1 As shown, dew point meters are installed in both the soaking furnace 3 and the radiant tube cooling section 5 to detect the dew point in the soaking furnace 3 and the radiant tube cooling section 5.

[0104] Example

[0105] Combination Figure 1 As shown, Examples 1-3 employ the method and normalizing furnace of the present invention for reducing oxidation of non-oriented silicon steel normalizing plates. Some process parameters are shown in Table 1, and the specific process is as follows:

[0106] I. Requirements for the Arrangement and Gap Control of Inlet and Outlet Sealing Rollers. During the strip normalizing process, sealing rollers rotate via furnace rollers. Sealing rollers are arranged at the inlet and outlet of the normalizing furnace. The inlet sealing rollers are located at the inlet of the non-oxidizing heating furnace, and the outlet sealing rollers are located at the outlet sealing chamber at the end of the radiant tube cooling section. The lower sealing roller supports the strip, and the upper roller rotates via a motor. The maximum product thickness is h.m The unit is mm; the gap between the upper and lower rollers is h, in mm; k1 is the roller gap compensation coefficient, 0 < k1 ≤ 5. To reduce atmospheric entry into the non-oxidizing heating furnace and the radiant tube cooling section, h = h m +k1.

[0107] II. Sealing control requirements for the inlet and outlet of the normalizing furnace and adjacent sections of the furnace area. This mainly includes the control requirements for the inlet sealing chamber, furnace throat, isolation section, and outlet sealing chamber.

[0108] 1) The number of N2 injection points in the inlet sealing chamber Y0 ≥ 1.

[0109] 2) The throat is located between the non-oxidizing furnace and the soaking furnace. To reduce the backflow of exhaust gas from the non-oxidizing furnace into the soaking furnace, a multi-layered sealing curtain and multiple N2 injection points are used for isolation and sealing. The height f1 of the sealing curtain in the throat section is controlled by an encoder (unit: mm), so f1 = h. m +k2, k2 is the compensation coefficient of the furnace throat sealing curtain, 0<k2≤10, the number of sealing curtains arranged is X1≥2, one N2 injection point is arranged between adjacent sealing curtains, and the number of furnace throat N2 injection points is Y1=X1-1.

[0110] 3) The soaking furnace and the radiant tube cooling section are isolated by a sealing curtain. The number of sealing curtains X2≥1, and the lifting height of the sealing curtain is f2 in mm. Then f2=hm+k3, where k3 is the compensation coefficient of the sealing curtain in the isolation section, 0<k3≤10.

[0111] 4) The radiant tube cooling section outlet sealing chamber is designed with multiple sealing curtains and N2 injection point isolation sealing. The number of sealing curtains X3≥2, and the lifting height of the sealing curtains is f3 (in mm). Therefore, f3=h m +k4, where k4 is the compensation coefficient for the sealing curtain of the outlet sealing chamber, 0 < k4 ≤ 10. An N2 injection point is arranged between adjacent sealing curtains, and the number of N2 injection points in the outlet sealing chamber is Y4 = X3 - 1.

[0112] III. N2 Control Requirements in the Furnace Area. To control furnace pressure and dew point in the normalizing furnace area, N2 injection points are arranged in the furnace section area, mainly including: the soaking furnace and the radiant tube cooling section.

[0113] 1) Number of N2 injection points in the soaking furnace Y2 = Number of furnace zones in the soaking furnace.

[0114] 2) The number of N2 injection points in the radiant tube cooling section, Y3, is ≥ 1;

[0115] 3) The dew point rise slope is ΔT / Δt, in °C / h; the dew point rise slopes of the soaking furnace and the radiant tube cooling section are represented by k5 and k6, respectively. When k5≥5, the N2 injection amount of the soaking furnace is increased by 10% based on the set value. When k6≥5, the N2 injection amount of the soaking furnace is increased by 10% based on the set value.

[0116] IV. Pressure Control Requirements for Normalizing Furnaces. The inlet pressure of the non-oxidizing heating furnace is P1 (Pa); the outlet pressure of the non-oxidizing heating furnace is P2 (Pa); the inlet pressure of the soaking furnace is P3 (Pa); the outlet pressure of the soaking furnace is P4 (Pa); and the outlet pressure of the radiant tube cooling section is P5 (Pa).

[0117] 1) Select the furnace pressure P1 at the inlet section of the non-oxidizing heating furnace as the reference furnace pressure for normalizing furnace control. Adjust and control the normalizing furnace exhaust fan speed and baffle opening. Use large furnace pressure control to prevent air from being drawn into the furnace from the inlet sealing roller gap due to atmospheric fluctuations in the normalizing furnace. k7 is the inlet furnace pressure compensation coefficient, 0≤k7≤30, P1=26+k7.

[0118] 2) In order to minimize the backflow of exhaust gas from the non-oxidizing heating furnace to the soaking furnace, the furnace pressure difference δP1 between the inlet of the soaking furnace and the outlet of the non-oxidizing heating furnace is controlled with a large value to form a large gradient atmosphere. δP1 is automatically controlled by adjusting the amount of N2 injected into the furnace throat and the soaking furnace. k8 is the furnace throat pressure compensation coefficient, 0≤k8≤50, δP1=P3-P2≥15+k8.

[0119] 3) The number of furnace zones in the soaking furnace is M, and each furnace zone has one N2 injection point, which can be used to adjust the furnace pressure gradient and control the atmosphere of the soaking furnace from the outlet to the inlet. The difference between the furnace pressure at the outlet and the furnace pressure at the inlet of the soaking furnace is δP2, and k9 is the furnace pressure compensation coefficient of the soaking furnace, 0≤k9≤20, δP2=P4-P3=5+k9.

[0120] 4) The entire furnace atmosphere flow direction is from the outlet of the radiant tube cooling section of the normalizing furnace to the inlet of the non-oxidizing heating furnace. The furnace pressure at the outlet of the radiant tube cooling section is taken as the highest furnace pressure point. The furnace pressure of the normalizing furnace gradually decreases from the outlet of the radiant tube cooling section to the inlet of the non-oxidizing heating furnace (see...). Figure 1 As shown), the pressure difference between the outlet furnace pressure of the radiant tube cooling section and the outlet furnace pressure of the soaking furnace is δP3, k. 10 k is the furnace pressure compensation coefficient for radiant tube furnaces, 0≤k 10 ≤10, δP3=P5-P4=1+k 10 .

[0121] 5. Control the furnace pressure by using analytical instruments to detect numerical feedback.

[0122] 1) The oxygen content feedback control furnace pressure regulator for the non-oxidizing heating furnace is set up with an oxygen analyzer at the outlet of the end section of the non-oxidizing heating furnace. When the O2 value detected by the oxygen analyzer increases by 0.1%, the N2 injection amount in the furnace throat and the soaking furnace is adjusted to make δP1 > 40Pa.

[0123] 2) The soaking furnace adopts electric heating. A CO analyzer is installed at the inlet section of the soaking furnace. The CO content can characterize the degree of backflow of exhaust gas from the non-oxidizing heating furnace. When the CO content detected by the CO analyzer increases by 0.1%, the N2 injection rate of the soaking furnace and the radiant tube cooling section is adjusted to make δP2 > 10Pa.

[0124] Table 1 Process parameters for Examples 1-3

[0125]

[0126] In summary, the above embodiments, when implemented in newly built normalizing units, ensured stable atmosphere control in the normalizing furnace, maintained furnace pressure gradients within the set range in each section, and stable dew points in the soaking furnace and radiant tube cooling sections. This effectively reduced oxidation of non-oriented silicon steel normalized plates, and no cases of severe product oxidation occurred.

[0127] Those skilled in the art should recognize that the above embodiments are merely illustrative of the present invention and are not intended to limit the present invention. Any variations or modifications to the above embodiments that are within the spirit and essence of the present invention will fall within the scope of the claims of the present invention.

Claims

1. A method for reducing oxidation of normalized non-oriented silicon steel plates, characterized in that: Sealing rollers are arranged at the inlet and outlet of the normalizing furnace, and the roller gap of the sealing rollers is controlled. A height-adjustable sealing curtain and injected N2 are used to control the sealing of the normalizing furnace inlet and outlet as well as the furnace area; The furnace pressure of the normalizing furnace is controlled by using the furnace pressure at the inlet of the non-oxidizing heating furnace as the control reference furnace pressure, so as to ensure that the furnace pressure of the normalizing furnace gradually decreases from the outlet of the radiant tube cooling section to the inlet of the non-oxidizing heating furnace. Analytical instruments are installed inside the normalizing furnace, and the furnace pressure is controlled based on the feedback data from the analytical instruments.

2. The method for reducing oxidation of normalized non-oriented silicon steel plates according to claim 1, characterized in that: The sealing roller at the inlet of the normalizing furnace is installed at the inlet of the non-oxidizing heating furnace, and the sealing roller at the outlet of the normalizing furnace is installed at the outlet sealing chamber at the end of the radiant tube cooling section. The lower roller of the sealing roller supports the strip steel, and the upper roller of the sealing roller is driven by a motor; The gap between the sealing rollers satisfies: h = h m +k1; where h is the roll gap of the sealing roller, in mm; h m is the maximum thickness of the strip, in mm, and k1 is the roll gap compensation coefficient, 0 < k1 ≤ 5.

3. The method for reducing oxidation of normalized non-oriented silicon steel plates according to claim 1, characterized in that, The sealing control methods for the inlet and outlet of the normalizing furnace and the furnace area are as follows: S21, the number of N2 injection points Y0≥1 is set in the sealed chamber at the inlet of the non-oxidizing heating furnace; S22, the furnace throat between the non-oxidizing heating furnace and the soaking furnace is isolated and sealed by multiple height-adjustable sealing curtains and multiple N2 injection points; S23, multiple N2 injection points are set in both the soaking furnace and the radiant tube cooling section; S24, a height-adjustable sealing curtain is used to isolate and seal the isolation section between the soaking furnace and the radiant tube cooling section; S25 employs multiple height-adjustable sealing curtains and multiple N2 injection points to isolate and seal the outlet sealing chamber at the end of the radiant tube cooling section.

4. The method for reducing oxidation of normalized non-oriented silicon steel plates according to claim 3, characterized in that, In step S22: The lifting height f1 of the sealing curtain installed in the furnace throat satisfies: f1 = h m +k2, where f1 is the lifting height of the sealing curtain in mm, h m is the maximum thickness of the strip steel, in mm; k2 is the compensation coefficient of the furnace throat sealing curtain, 0 < k2 ≤ 10; The number of sealing curtains in the furnace throat is X1≥2, and an N2 injection point is arranged between adjacent sealing curtains. The number of N2 injection points in the furnace throat is Y1=X1-1.

5. The method for reducing oxidation of normalized non-oriented silicon steel plates according to claim 3, characterized in that, In step S23: The number of N2 injection points Y2 in the soaking furnace is equal to the number of furnace zones in the soaking furnace; The number of N2 injection points in the radiant tube cooling section Y3 is ≥ 1; The N2 injection rate of the soaking furnace satisfies the following: the dew point rise slope of the soaking furnace is k5 = ΔT / Δt, with the unit being ℃ / h. When k5 ≥ 5, the N2 injection rate of the soaking furnace is increased by 10% based on the set value. The N2 injection amount of the radiant tube cooling section satisfies the following: the dew point rise slope of the radiant tube cooling section is k6 = ΔT / Δt, with the unit being ℃ / h. When k6 ≥ 5, the N2 injection amount of the radiant tube cooling section is increased by 10% based on the set value.

6. The method for reducing oxidation of normalized non-oriented silicon steel plates according to claim 3, characterized in that, In step S24, the number of sealing curtains in the isolation section X2≥1, and the lifting height f2 of the sealing curtains satisfies: f2=h m +k3, where f2 is the lifting height of the sealing curtain in mm, h m K represents the maximum thickness of the strip steel in mm, and k3 is the compensation coefficient of the sealing curtain of the isolation section, where 0 < k3 ≤ 10.

7. The method for reducing oxidation of normalized non-oriented silicon steel plates according to claim 3, characterized in that, In step S25: The number of sealing curtains in the outlet sealing chamber is X3≥2, and an N2 injection point is arranged between adjacent sealing curtains. The number of N2 injection points in the outlet sealing chamber is Y4=X3-1. The lifting height f3 of the sealing curtain installed in the outlet sealing chamber satisfies: f2 = h m +k4, where f3 is the lifting height of the sealing curtain in mm, h m K is the maximum thickness of the strip steel in mm, and k4 is the compensation coefficient of the sealing curtain of the outlet sealing chamber, where 0 < k4 ≤ 10.

8. The method for reducing oxidation of normalized non-oriented silicon steel plates according to claim 1, characterized in that, The process for controlling the furnace pressure of the normalizing furnace is as follows: S31, using the inlet furnace pressure of the non-oxidizing heating furnace as the control reference furnace pressure, the furnace pressure of the non-oxidizing heating furnace is adjusted and controlled by adjusting the speed of the exhaust fan of the normalizing furnace and the opening of the baffle. S32, the furnace pressure difference between the inlet of the soaking furnace and the outlet of the non-oxidizing heating furnace is controlled by adjusting the amount of N2 injected into the furnace throat and the soaking furnace; S33, by adjusting the N2 injection amount in each furnace zone of the soaking furnace, the furnace pressure gradient of the soaking furnace is controlled to control the atmosphere of the soaking furnace to flow from the outlet to the inlet; S34, the flow direction of the atmosphere in the normalizing furnace is from the outlet of the radiant tube cooling section to the inlet of the non-oxidizing heating furnace. The furnace pressure at the outlet of the radiant tube cooling section is the highest furnace pressure point. The furnace pressure of the normalizing furnace gradually decreases from the outlet of the radiant tube cooling section to the inlet of the non-oxidizing heating furnace.

9. The method for reducing oxidation of normalized non-oriented silicon steel plates according to claim 8, characterized in that: In step S31, the inlet furnace pressure P1 of the non-oxidizing heating furnace satisfies: P1=26+k7, where P1 is the inlet furnace pressure of the non-oxidizing heating furnace in Pa, and k7 is the inlet furnace pressure compensation coefficient, 0≤k7≤30; In step S32, the furnace pressure difference δP1 between the inlet of the soaking furnace and the outlet of the non-oxidizing heating furnace satisfies: δP1=P3-P2≥15+k8, where δP1 is the furnace pressure difference between the inlet of the soaking furnace and the outlet of the non-oxidizing heating furnace, in Pa; P2 is the furnace pressure at the outlet of the non-oxidizing heating furnace, in Pa; P3 is the furnace pressure at the inlet of the soaking furnace, in Pa; and k8 is the furnace throat pressure compensation coefficient, 0≤k8≤50. In step S33, the furnace pressure difference δP2 between the outlet and inlet of the soaking furnace satisfies: δP2=P4-P3=5+k9, where δP2 is the furnace pressure difference between the outlet and inlet of the soaking furnace, in Pa; P4 is the furnace pressure at the outlet of the soaking furnace, in Pa; and k9 is the furnace pressure compensation coefficient of the soaking furnace, 0≤k9≤20. In step S34, the furnace pressure difference δP3 between the outlet of the radiant tube cooling section and the outlet of the soaking furnace satisfies: δP3=P5-P4=1+k 10 In the formula, δP3 is the furnace pressure difference between the outlet of the radiant tube cooling section and the outlet of the soaking furnace, in Pa; P5 is the furnace pressure at the outlet of the radiant tube cooling section, in Pa, kJ / m³. 10 k is the furnace pressure compensation coefficient for radiant tube furnaces, 0≤k 10 ≤10.

10. The method for reducing oxidation of normalized non-oriented silicon steel plates according to claim 1, characterized in that, The process of controlling the furnace pressure of the normalizing furnace based on feedback data from analytical instruments is as follows: S41, an oxygen analyzer is installed at the outlet of the non-oxidizing heating furnace of the normalizing furnace, and a CO analyzer is installed at the inlet of the soaking furnace. S42, the oxygen content at the outlet of the non-oxidizing heating furnace is detected by an oxygen analyzer. When the oxygen analyzer detects an increase of 0.1% in the O2 content, the furnace pressure difference δP1 between the inlet of the soaking furnace and the outlet of the non-oxidizing heating furnace is made to be greater than 40 Pa by adjusting the N2 injection amount of the furnace throat and the soaking furnace. S43, the CO content at the inlet of the soaking furnace is detected by a CO analyzer. When the CO content detected by the CO analyzer increases by 0.1%, the N2 injection rate of the soaking furnace and the radiant tube cooling section is adjusted to make the furnace pressure difference δP2 between the outlet and inlet of the soaking furnace > 10 Pa.

11. A normalizing furnace for reducing oxidation of non-oriented silicon steel normalizing plates, comprising a non-oxidizing heating furnace, a furnace throat, a soaking furnace, an isolation section, and a radiant tube cooling section arranged sequentially, characterized in that: Sealing rollers are respectively installed at the inlet of the non-oxidizing heating furnace and at the outlet of the radiant tube cooling section; the inlet of the non-oxidizing heating furnace is provided with an inlet sealing chamber; the end of the radiant tube cooling section is provided with an outlet sealing chamber; The inlet sealing chamber, soaking furnace, and radiant tube cooling section of the non-oxidizing heating furnace are isolated and sealed by injecting N2. The isolation section is sealed using a height-adjustable sealing curtain; The furnace throat and the outlet sealing chamber at the end of the radiant tube cooling section are isolated and sealed by multiple height-adjustable sealing curtains and multiple N2 injection points, with an N2 injection point arranged between adjacent sealing curtains. An oxygen analyzer is installed at the outlet of the non-oxidizing heating furnace, and a CO analyzer is installed at the inlet of the homogenizing furnace.

12. The normalizing furnace for reducing oxidation of non-oriented silicon steel normalizing plates according to claim 11, characterized in that: The inlet sealed chamber of the non-oxidizing heating furnace is provided with at least one N2 injection point; The homogenizing furnace is equipped with multiple N2 injection points, and each furnace zone of the homogenizing furnace is equipped with one N2 injection point. The number of N2 injection points is equal to the number of furnace zones of the homogenizing furnace. The radiant tube cooling section is provided with at least one N2 injection point.

13. The normalizing furnace for reducing oxidation of non-oriented silicon steel normalizing plates according to claim 11, characterized in that: The isolation section is equipped with at least one height-adjustable sealing curtain; The number of sealing curtains arranged in the furnace throat is ≥2, and the number of N2 injection points in the furnace throat is one less than the number of sealing curtains arranged. The number of sealing curtains arranged in the outlet sealing chamber is ≥2, and the number of N2 injection points in the outlet sealing chamber is one less than the number of sealing curtains arranged.

14. The normalizing furnace for reducing oxidation of non-oriented silicon steel normalizing plates according to claim 11, characterized in that: Both the soaking furnace and the radiant tube cooling section are equipped with dew point meters.

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