Semi-process non-oriented silicon steel production method adopting carbon steel continuous annealing furnace

Abstract

The invention relates to a semi-process non-oriented silicon steel production method adopting a carbon steel continuous annealing furnace. The semi-process non-oriented silicon steel production method comprises the steps of smelting, continuous casting, hot rolling, acid pickling, cold rolling, annealing and flattening. The key control comprises the following steps: 1) hot rolling: heating a plate blank in a furnace, and preserving heat at 850-900 DEG C in a preheating section for 0.8-1.0 h; heat preservation is conducted for 1.0-1.2 h at the high-temperature section of 950-1190 Heat preservation is conducted for 0.5-1.5 h at the temperature of 1100-1150 DEG C in the soaking The finish rolling temperature is 840-880 DEG C, and the coiling temperature is 660-700 DEG C; and 2) annealing: annealing by adopting a carbon steel continuous annealing furnace at the annealing temperature of 650-850 DEG C and the running speed of 80-200m / min. The purpose of producing the semi-process non-oriented silicon steel through the carbon steel continuous annealing furnace is achieved, and it can be guaranteed that the magnetic induction, hardness, iron loss and other aspects of non-oriented silicon steel products all meet the requirements of high-end products.

Description

Technical Field

[0001] This invention relates to the field of non-oriented silicon steel production technology, and in particular to a semi-process non-oriented silicon steel production method using a carbon steel continuous annealing furnace. Background Technology

[0002] Non-oriented silicon steel typically refers to low-carbon steel with a silicon content of 0.5% to 3.5%. The grains in non-oriented silicon steel are randomly arranged, and its magnetic properties are isotropic (i.e., the magnetization characteristics are similar in all directions). Non-oriented silicon steel is an important soft magnetic material, mainly used in the manufacture of cores for electrical equipment such as motors, transformers, and generators. Its excellent magnetic properties and high permeability can effectively reduce iron loss and improve equipment efficiency.

[0003] There are many types of non-oriented silicon steel, each with different applications and advantages and disadvantages, but all require very strict performance and quality standards. The quality of non-oriented silicon steel directly affects the service life of electrical equipment and even the safety of the entire electrical device during operation.

[0004] Semi-processed non-oriented silicon steel is a type of silicon steel material that is annealed after cold rolling but not subjected to final annealing. Users need to perform annealing themselves after stamping into cores to optimize final magnetic properties. It offers processing flexibility and cost advantages; users can eliminate stress through annealing after stamping and customize magnetic properties. By eliminating the final annealing step, production energy consumption and costs are reduced. The final performance of non-oriented silicon steel products depends on subsequent processing, determined by the user's annealing process parameters (including temperature, time, and atmosphere).

[0005] The conventional production process of semi-process non-oriented silicon steel includes smelting and hot rolling, pickling and cold rolling, intermediate annealing, finishing, and coating. Intermediate annealing typically uses a bell-type annealing furnace. However, carbon steel production often employs a continuous annealing furnace (referred to as a carbon steel continuous annealing furnace). Continuous annealing furnaces and bell-type annealing furnaces differ significantly in process objectives, equipment design, and control parameters due to the different material properties and final performance requirements. Bell-type annealing furnaces have a slow heating rate, which is detrimental to grain growth and results in lower production efficiency, while continuous annealing furnaces have a fast heating rate, which is beneficial to grain growth and results in higher production efficiency. Therefore, this invention develops a method for producing non-oriented silicon steel using a carbon steel continuous annealing furnace. Summary of the Invention

[0006] This invention provides a semi-process non-oriented silicon steel production method using a carbon steel continuous annealing furnace, achieving the goal of producing semi-process non-oriented silicon steel using a carbon steel continuous annealing furnace, and ensuring that the non-oriented silicon steel products meet the requirements of high-end products in terms of magnetic induction, hardness, and iron loss.

[0007] To achieve the above objectives, the present invention employs the following technical solution:

[0008] A semi-process method for producing non-oriented silicon steel using a carbon steel continuous annealing furnace. The production process of non-oriented silicon steel includes smelting, continuous casting, hot rolling, pickling, cold rolling, annealing, and leveling; the following processes are controlled:

[0009] 1) Hot rolling: The slab is heated in the furnace. The preheating zone temperature is 850-900℃, heated under a slight negative pressure of -5Pa to -50Pa, and the holding time is 0.8-1.0h; the high temperature zone temperature is 950-1190℃, and the holding time is 1.0-1.2h; the soaking zone temperature is 1100-1150℃, and the holding time is 0.5-1.5h; the hot rolling final rolling temperature is 840-880℃, and the coiling temperature is 660-700℃.

[0010] 2) Annealing: The steel coils are annealed in a carbon steel continuous annealing furnace. The annealing temperature is controlled at 650-850℃ and the running speed of the carbon steel continuous annealing furnace is controlled at 80-200m / min.

[0011] The chemical composition of non-oriented silicon steel, by mass percentage, is: C ≤ 0.003%; Si: 0.30%–1.0%; Mn: 0.4%–0.8%; P: 0.04%–0.14%; S < 0.0040%; Al: 0.10%–0.50%; with the balance being Fe and unavoidable impurities.

[0012] The thickness of continuously cast slabs is 225–235 mm, and the thickness of hot-rolled coils is 2.0–3.0 mm.

[0013] After hot rolling, the steel coils are pickled with hydrochloric acid with a mass concentration of 5% to 20% and then cold rolled. The cold rolling is carried out using a five-stand six-roll continuous rolling mill.

[0014] The elongation rate during leveling is controlled at 1% to 5%, and the surface roughness Ra of the steel strip after leveling is 0.6 to 1.2 μm.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] (1) The semi-process non-oriented silicon steel is produced by using a carbon steel continuous annealing furnace, which ensures the magnetic properties of the steel.

[0017] (2) By matching reasonable component design with appropriate production process, the surface quality of the product is guaranteed.

[0018] (3) The finished steel products can meet the requirements of high-end products in terms of magnetic induction, hardness and iron loss. Detailed Implementation

[0019] The present invention discloses a semi-process method for producing non-oriented silicon steel using a carbon steel continuous annealing furnace. The production process of non-oriented silicon steel includes smelting, continuous casting, hot rolling, pickling, cold rolling, annealing, and leveling; the following processes are controlled:

[0020] 1) Hot rolling: The slab is heated in the furnace. The preheating zone temperature is 850-900℃, heated under a slight negative pressure of -5Pa to -50Pa, and the holding time is 0.8-1.0h; the high temperature zone temperature is 950-1190℃, and the holding time is 1.0-1.2h; the soaking zone temperature is 1100-1150℃, and the holding time is 0.5-1.5h; the hot rolling final rolling temperature is 840-880℃, and the coiling temperature is 660-700℃.

[0021] 2) Annealing: The steel coils are annealed in a carbon steel continuous annealing furnace. The annealing temperature is controlled at 650-850℃ and the running speed of the carbon steel continuous annealing furnace is controlled at 80-200m / min.

[0022] The chemical composition of non-oriented silicon steel, by mass percentage, is: C ≤ 0.003%; Si: 0.30%–1.0%; Mn: 0.4%–0.8%; P: 0.04%–0.14%; S < 0.0040%; Al: 0.10%–0.50%; with the balance being Fe and unavoidable impurities.

[0023] The thickness of continuously cast slabs is 225–235 mm, and the thickness of hot-rolled coils is 2.0–3.0 mm.

[0024] After hot rolling, the steel coils are pickled with hydrochloric acid with a mass concentration of 5% to 20% and then cold rolled. The cold rolling is carried out using a five-stand six-roll continuous rolling mill.

[0025] The elongation rate during leveling is controlled at 1% to 5%, and the surface roughness Ra of the steel strip after leveling is 0.6 to 1.2 μm.

[0026] This invention uses a carbon steel continuous annealing furnace to produce semi-process non-oriented silicon steel. The carbon steel continuous annealing furnace has a fast heating rate, which can heat the steel plate from room temperature to 850°C in a short time. This meets the high-temperature and rapid process characteristics required for silicon steel annealing, which is conducive to promoting grain growth in non-oriented silicon steel and reducing iron loss in non-oriented silicon steel.

[0027] To more intuitively illustrate the present invention, the embodiments of the present invention will be further described in conjunction with the examples. The following examples are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any technical solutions that can be obviously obtained by those skilled in the art within the scope of the technology disclosed in the present invention, including simple variations or equivalent substitutions, are all within the scope of protection of the present invention.

[0028]

Example 1

[0029] This embodiment produces semi-process non-oriented silicon steel. Annealing is carried out using a carbon steel continuous annealing furnace. The specific production process is as follows:

[0030] 1. Optimization of chemical composition of non-oriented silicon steel;

[0031] The chemical composition of non-oriented silicon steel, by mass percentage, is: C: 0.002%; Si: 0.55%; Mn: 0.5%; P: 0.07%; S: 0.0020%; Al: 0.25%; with the balance being Fe and unavoidable impurities.

[0032] 2. Hot rolling;

[0033] The thickness of the continuously cast slab is 230mm.

[0034] Heating process parameters: The preheating section temperature is 875℃, heated under a slight negative pressure of -20Pa, and held for 0.9h; the high temperature section temperature is 1180℃, and held for 1.1h; the soaking section temperature is 1130℃, and held for 0.5h.

[0035] The finishing rolling temperature is 860℃, the coiling temperature is 680℃, and the thickness of the hot-rolled coil is 2.75mm.

[0036] 3. Cold rolling;

[0037] After hot rolling, the steel coils are pickled with 10% hydrochloric acid and then cold rolled using a five-stand, six-roll continuous rolling mill.

[0038] 4. Annealing;

[0039] The steel coils are annealed in a carbon steel continuous annealing furnace; the annealing temperature is controlled at 700℃ according to the required electromagnetic performance, and the operating speed of the carbon steel continuous annealing furnace is controlled at 120m / min.

[0040] 5. Flat;

[0041] The flattening elongation rate is controlled at 2%, and the surface roughness Ra of the flattened steel strip is 0.8μm, so no anti-rust oil is required.

[0042] The inspection results of the semi-process non-oriented silicon steel products produced in this embodiment are shown in Table 1.

[0043]

Example 2

[0044] This embodiment produces semi-process non-oriented silicon steel. Annealing is carried out using a carbon steel continuous annealing furnace. The specific production process is as follows:

[0045] 1. Optimization of chemical composition of non-oriented silicon steel;

[0046] The chemical composition of non-oriented silicon steel, by mass percentage, is: C: 0.001%; ​​Si: 0.58%; Mn: 0.5%; P: 0.07%; S: 0.0018%; Al: 0.20%; with the balance being Fe and unavoidable impurities.

[0047] 2. Hot rolling;

[0048] The thickness of the continuously cast slab is 232 mm.

[0049] Heating process parameters: The preheating section temperature is 870℃, heated under a slight negative pressure of -20Pa, and held for 0.5h; the high temperature section temperature is 1180℃, and held for 1h; the soaking section temperature is 1124℃, and held for 0.5h.

[0050] The finishing rolling temperature is 860℃, the coiling temperature is 685℃, and the thickness of the hot-rolled coil is 2.25mm.

[0051] 3. Cold rolling;

[0052] After hot rolling, the steel coils are pickled with 12% hydrochloric acid and then cold rolled using a five-stand, six-roll continuous rolling mill.

[0053] 4. Annealing;

[0054] The steel coils are annealed in a carbon steel continuous annealing furnace; the annealing temperature is controlled at 800℃ according to the required electromagnetic performance, and the operating speed of the carbon steel continuous annealing furnace is controlled at 130m / min.

[0055] 6. Flat;

[0056] The flattening elongation rate is controlled at 5%, and the surface roughness Ra of the flattened steel strip is 0.9μm, so no anti-rust oil is required.

[0057] The inspection results of the semi-process non-oriented silicon steel products produced in this embodiment are shown in Table 1.

[0058]

Example 3

[0059] This embodiment produces semi-process non-oriented silicon steel. Annealing is carried out using a carbon steel continuous annealing furnace. The specific production process is as follows:

[0060] 1. Optimization of chemical composition of non-oriented silicon steel;

[0061] The chemical composition of non-oriented silicon steel, by mass percentage, is: C: 0.002%; Si: 0.6%; Mn: 0.6%; P: 0.09%; S: 0.0020%; Al: 0.22%; with the balance being Fe and unavoidable impurities.

[0062] 2. Hot rolling;

[0063] The thickness of the continuously cast slab is 230mm.

[0064] Heating process parameters: The preheating section temperature is 870℃, heated under a slight negative pressure of -20Pa, and held for 0.5h; the high temperature section temperature is 1160℃, and held for 1.1h; the soaking section temperature is 1120℃, and held for 0.6h.

[0065] The finishing rolling temperature is 870℃, the coiling temperature is 670℃, and the thickness of the hot-rolled coil is 2.5mm.

[0066] 3. Cold rolling;

[0067] After hot rolling, the steel coils are pickled with 9% hydrochloric acid and then cold rolled using a five-stand, six-roll continuous rolling mill.

[0068] 4. Annealing;

[0069] The steel coils are annealed in a carbon steel continuous annealing furnace; the annealing temperature is controlled at 750℃ according to the required electromagnetic performance, and the operating speed of the carbon steel continuous annealing furnace is controlled at 115m / min.

[0070] 7. Flat;

[0071] The flattening elongation rate is controlled at 5%, and the surface roughness Ra of the flattened steel strip is 0.9μm, so no anti-rust oil is required.

[0072] The inspection results of the semi-process non-oriented silicon steel products produced in this embodiment are shown in Table 1.

[0073] Table 1 Inspection Results of Semi-Process Non-Oriented Silicon Steel Products

[0074]

[0075] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for producing non-oriented silicon steel by a semi-process using a carbon steel continuous annealing furnace, wherein the production process of the non-oriented silicon steel comprises smelting, continuous casting, hot rolling, pickling, cold rolling, annealing and temper rolling, and is characterized in that, The process is controlled as follows: 1) Hot rolling: slab is heated in a furnace, the temperature in the preheating section is 850-900℃, the slab is heated under a micro negative pressure of -5Pa to -50Pa, the holding time is 0.8-1.0h; the temperature in the high temperature section is 950-1190℃, the holding time is 1.0-1.2h; the temperature in the soaking section is 1100-1150℃, the holding time is 0.5-1.5h; the final rolling temperature is 840-880℃, and the coiling temperature is 660-700℃; 2) Annealing: the steel coil is put into a carbon steel continuous annealing furnace for annealing treatment, the annealing temperature is controlled at 650-850℃, and the running speed of the carbon steel continuous annealing furnace is controlled at 80-200m / min.

2. A method of producing non-oriented silicon steel by a semi-process using a carbon steel continuous annealing furnace according to claim 1, characterized in that, The chemical composition of the non-oriented silicon steel, in terms of mass percentage, is C≤0.003%; Si: 0.30%-1.0%; Mn: 0.4%-0.8%; S: <0.0040%; Al: 0.10%-0.50%; and the balance is Fe and inevitable impurities. P：0.04％～0.14％； The thickness of the continuous casting slab is 225-235mm, and the thickness of the hot-rolled coil is 2.0-3.0mm.

3. A method of producing non-oriented silicon steel by a semi-process using a carbon steel continuous annealing furnace according to claim 1, characterized in that, The hot-rolled coil is pickled with hydrochloric acid with a mass concentration of 5%-20% before cold rolling, and the cold rolling is performed by using a five-stand six-roll continuous rolling mill.

4. The method of producing non-oriented silicon steel by semi-process without taking out according to claim 1, characterized in that, The elongation during the skin pass is controlled at 1%-5%, and the surface roughness Ra of the steel strip after the skin pass is 0.6-1.2μm.

5. The method of producing non-oriented silicon steel by semi-process without taking out according to claim 1, characterized in that, ​

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