A production method for improving the quality of the edge portion of silicon steel

Abstract

The present application belongs to the technical field of special steel processing, and particularly relates to a silicon steel edge quality control method based on thin strip continuous casting production, in particular, an edge quality control method of the trimming process of hot coils. By coordinately controlling parameters such as the storage time of the hot coil in the intermediate warehouse, the uncoiling temperature at the trimming line, the temperature in the specific area of the edge, and the overlapping amount of shearing, the edge quality of the silicon steel is improved. By controlling the strip steel temperature according to the composition of the silicon steel, the temperature of the silicon steel with different compositions is determined, the purpose of effectively controlling the edge quality of the silicon steel after trimming is achieved, the quality problems of the silicon steel edge cracks, edge loss and edge cracks are solved, the rollability of the subsequent process of cold rolling is improved, and the cold rolling breakage rate is reduced to below 0.4%.

Description

Technical Field

[0001] This invention relates to the field of edge quality control technology for thin strip continuously cast silicon steel, and in particular to a production control method for improving the edge quality of silicon steel strip after edge trimming. Background Technology

[0002] The thin-strip casting and rolling process for silicon steel involves passing molten silicon steel through a distributor into a pair of counter-rotating crystallizing rollers. As the rollers rotate, the silicon steel thin casting strip is drawn out and then hot-rolled into hot-rolled thin strip steel in one or two passes, which is then coiled. After being stored in an intermediate warehouse for a certain period, the hot-rolled silicon steel coils are trimmed on a trimming production line for subsequent cold rolling.

[0003] The cold rolling production of silicon steel is quite difficult, and it has high requirements for the edge quality of the hot-rolled coil. Defects such as cracks, edge damage, and edge splits on the edge directly affect the rollability of the cold rolling process. These defects directly cause cold rolling strip breakage, affecting the production efficiency of cold rolling, as well as the strip yield and product quality.

[0004] Existing edge quality control methods for silicon steel cannot solve the edge trimming quality problem of hot-rolled silicon steel produced by thin strip casting and rolling processes. Patent 201310257357.3 provides a shearing method for high-yield-strength grain-oriented silicon steel to address the edge trimming problem after cold rolling and annealing, but does not address hot-rolled edge trimming quality control. Patent 201811485401.5 discloses a hot-rolled edge quality control method for low-temperature, high-magnetic-induction grain-oriented silicon steel, addressing defects at the strip edge during hot rolling by controlling the furnace temperature and roughing speed before hot rolling, but does not address edge trimming quality control. Patent 202311538937.X discloses a silicon steel strip shearing method that reduces the probability of strip breakage by controlling the coiling speed, but also does not address edge quality control. Patent 202410254672.9 discloses a method to improve the edge quality of hot-rolled grain-oriented silicon steel strip by adjusting the gap between the billet and the furnace before hot rolling to control the hot rolling exit temperature and improve the edge quality of the hot rolling process. Patent application 202411328187.8 discloses a production method to avoid edge cracking of hot-rolled grained silicon steel. By controlling the temperature of the billet in the heating furnace before hot rolling and the atmosphere in the heating furnace, the edge quality of the grained silicon steel is improved.

[0005] Existing technologies cannot solve the edge quality problem of hot-rolled silicon steel with a thickness of no more than 1.8 mm produced by thin strip continuous casting, nor do they address the defects such as cracks, edge damage, and edge splits that occur on the edge of thin strip steel. It is evident that solving the edge quality problem of hot-rolled silicon steel produced by thin strip casting and rolling is still a gap in existing technologies. Summary of the Invention

[0006] The purpose of this invention is to provide a production control method for improving the edge quality of hot-rolled thin-gauge silicon steel in thin strip casting and rolling production. By controlling the uncoiling temperature at the edge cutting line, the edge temperature of the strip in the edge cutting area, the overlap of the disc shear, and the coiling tension, the method solves the quality problems of edge cracks, edge damage, and edge splits after edge cutting of thin-gauge silicon steel, improves the rollability of subsequent cold rolling processes, and reduces the strip breakage rate in cold rolling.

[0007] Specifically, the technical solution adopted in this invention is as follows:

[0008] According to a first aspect of the present invention, a method for improving the edge quality of silicon steel is provided, the method comprising the following steps:

[0009] (1) Thin strip continuous casting and rolling: Steel with qualified composition is obtained by steelmaking in electric furnace or converter. The content of Si element in the steel is between 0.2-3.5wt%, the content of Mn is between 0.4-1.5wt%, and the content of Al is less than 1.5wt%. The steel is cast into a thin strip with a thickness of H by a pair of counter-rotating crystallizing rolls. Then, the thin strip is hot rolled into a thin strip steel with a thickness of h in one or two passes and coiled into a steel coil.

[0010] (2) The steel coils are stored in an intermediate warehouse;

[0011] (3) The steel coil is uncoiled by an uncoiler into the thin strip steel, wherein the uncoiling temperature of the steel coil at the shaving line is controlled at T. hr Between ±10℃, the single-sided trimming amount of the thin strip steel edge is A;

[0012] (4) Before the edge trimming process, the thin strip steel is heated in a heating furnace, and the temperature within the A+B region of the edge of the thin strip steel is controlled to be between Tc and 5℃, where the value of B is between 10-80mm. The temperature Tc is controlled as follows: Tc = 30.50 + 0.33x 3 -5.42x 2 +31.46x, where x is the sum of the Si and Al content of the thin strip steel;

[0013] (5) The heated thin strip steel is trimmed by a disc shear, the overlap of which is between D±0.01mm;

[0014] (6) The thin strip steel after trimming is coiled into coils by a coiler.

[0015] According to the production method for improving the edge quality of silicon steel according to the present invention, preferably, in the thin strip continuous casting and rolling in step (1), the thickness H of the thin strip cast by the crystallizing roll is in the range of 1.5-2.8 mm.

[0016] According to the production method for improving the edge quality of silicon steel of the present invention, preferably, in the continuous casting and rolling of thin strip in step (1), the thickness h of the thin strip steel after hot rolling is in the range of 0.8-1.8 mm.

[0017] According to the production method for improving the edge quality of silicon steel according to the present invention, preferably, in step (2), the steel coil is stored in the intermediate warehouse for 36-120 hours.

[0018] According to the production method for improving the edge quality of silicon steel of the present invention, preferably, in step (3), the uncoiling temperature T of the shaving wire is... hr The range of values ​​for is:

[0019]

[0020] According to the production method for improving the edge quality of silicon steel according to the present invention, preferably, in step (3), the edge cutting process adopts asymmetrical edge cutting, and the difference between the single-sided edge cutting amount on both sides is controlled between 0-20mm.

[0021] According to the production method for improving the edge quality of silicon steel according to the present invention, preferably, in step (3), the value of A is between 5 and 200 mm.

[0022] According to the production method for improving the edge quality of silicon steel according to the present invention, preferably, in step (5), the method for controlling the overlap amount is: D = 1.16 * h - 0.68.

[0023] According to the production method for improving the edge quality of silicon steel according to the present invention, preferably, in step (6), the winding tension is controlled between 10-25 MPa.

[0024] According to the production method for improving the edge quality of silicon steel of the present invention, preferably, optionally, the thin cast strip is directly coiled into a steel coil without undergoing a hot rolling process.

[0025] According to a second aspect of the invention, a thin strip steel is provided, wherein the production process of the thin strip steel employs one or more production methods having the aforementioned characteristics.

[0026] Beneficial technical effects

[0027] Compared with the prior art, the technical concept and corresponding technical solution of the present invention can achieve at least the following beneficial technical effects:

[0028] This invention addresses the edge quality issues of thin-gauge silicon steel hot-rolled coils produced by thin-strip continuous casting after edge trimming. It is the first to control the edge trimming process for thin-gauge silicon steel coils. By limiting the storage time of the hot-rolled coil in the intermediate warehouse after it comes off the production line, the unwinding temperature of the thin-gauge silicon steel coil at the edge trimming line is controlled. Simultaneously, based on the composition and microstructure of the silicon steel, the control range of the edge temperature during trimming is determined. Furthermore, the overlap of the coils at the edge trimming line is controlled according to the thickness of the thin-gauge silicon steel. This improves the stability of the silicon steel coil edge trimming, enhances the edge quality of the silicon steel coil after trimming, solves problems such as cracks, edge damage, and edge splitting after trimming, improves the edge quality of the silicon steel coil, reduces strip breakage during subsequent cold rolling, and increases the rolling yield. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention.

[0030] Figure 1 This is a schematic diagram of defects in the rolled edge of silicon steel.

[0031] Figure 2 This is a schematic diagram of the silicon steel rolled edge portion of the present invention. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0033] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0034] The following are embodiments of the present invention. The described embodiments are only a part of the embodiments of the present invention. All other embodiments that can be obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0035] The present invention will be further illustrated below through specific embodiments 1-3:

[0036] Example 1

[0037] Molten steel with a Si content of 0.4 wt% and a Mn content of 0.5 wt% is obtained through electric arc furnace or converter steelmaking. This molten steel is then cast into a 2.5 mm thick thin strip using a pair of counter-rotating crystallizing rolls. After hot rolling, it is produced into a 1.6 mm thick strip and coiled. The coil is then stored in an intermediate warehouse for 110 hours, followed by edge trimming at 30°C. The edge trimming on each side of the hot-rolled strip is 40 mm, and the temperature within 80 mm of the edge is heated to 42.2°C using a heater. The disc shear overlap is 1.2 mm, and the coiling tension is 23 MPa. The trimmed strip is then coiled for cold rolling, with no breakage during the cold rolling process.

[0038] Example 2

[0039] Molten steel with the required composition is obtained through electric arc furnace or converter steelmaking, containing 2.2 wt% Si, 0.8 wt% Mn, and 0.5 wt% Al. This molten steel is then cast into a 2.0 mm thick thin strip using a pair of counter-rotating crystallizing rolls. After hot rolling, it is produced into a 1.3 mm thick strip and coiled. The coil is then stored in an intermediate warehouse for 90 hours, followed by edge trimming at 43°C. The edge trimming is 80 mm on each side, and the temperature within 140 mm of the edge is heated to 82.4°C. The disc shear overlap is 0.8 mm, and the coiling tension is 18 MPa. The trimmed strip is then coiled for cold rolling, with no breakage during the cold rolling process.

[0040] Example 3

[0041] Molten steel with the required composition is obtained through electric arc furnace or converter steelmaking, containing 3.3 wt% Si, 1.2 wt% Mn, and 1.0 wt% Al. This molten steel is then cast into a 1.8 mm thick thin strip using a pair of counter-rotating crystallizing rolls. After hot rolling, it is produced into a 0.9 mm thick strip and coiled. The coil is then stored in an intermediate warehouse for 40 hours, followed by edge trimming at 65°C. The edge trimming on the hot-rolled strip is 120 mm, and the temperature within 195 mm of the edge is heated to 91.8°C. The disc shear overlap is 0.4 mm, and the coiling tension is 12 MPa. The trimmed strip is then coiled for cold rolling, with no breakage during the cold rolling process.

[0042] The above description is only a specific embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A production method for improving the edge quality of silicon steel, characterized in that, The production method includes the following steps: (1) Thin strip continuous casting and rolling: Steel with qualified composition is obtained by steelmaking in electric furnace or converter. The content of Si element in the steel is between 0.2-3.5wt%, the content of Mn is between 0.4-1.5wt%, and the content of Al is less than 1.5wt%. The steel is cast into a thin strip with a thickness of H by a pair of counter-rotating crystallizing rolls. Then, the thin strip is hot rolled into a thin strip steel with a thickness of h in one or two passes and coiled into a steel coil. (2) The steel coils are stored in an intermediate warehouse; (3) The steel coil is uncoiled by an uncoiler into the thin strip steel, wherein the uncoiling temperature of the steel coil at the shaving line is controlled at T. hr Between ±10℃, the single-sided trimming amount of the thin strip steel edge is A; (4) Before the edge trimming process, the thin strip steel is heated in a heating furnace, and the temperature within the A+B region of the edge of the thin strip steel is controlled to be between Tc and 5℃, where the value of B is between 10-80mm. The temperature Tc is controlled as follows: Tc = 30.50 + 0.33x 3 -5.42x 2 +31.46x, where x is the sum of the Si and Al content of the thin strip steel; (5) The heated thin strip steel is trimmed by a disc shear, the overlap of which is between D±0.01mm; (6) The thin strip steel after trimming is coiled into coils by a coiler.

2. The production method for improving the edge quality of silicon steel according to claim 1, characterized in that: In the thin strip continuous casting and rolling in step (1), the thickness H of the thin strip cast by the crystallizing roll ranges from 1.5 to 2.8 mm.

3. The production method for improving the edge quality of silicon steel according to claim 1, characterized in that: In the continuous casting and rolling of thin strip in step (1), the thickness h of the thin strip after hot rolling is in the range of 0.8-1.8 mm.

4. The production method for improving the edge quality of silicon steel according to claim 1, characterized in that: In step (2), the steel coil is stored in the intermediate warehouse for 36-120 hours.

5. The production method for improving the edge quality of silicon steel according to claim 1, characterized in that: In step (3), the unwinding temperature T of the tangent wire hr The range of values ​​for is:

6. The production method for improving the edge quality of silicon steel according to claim 1, characterized in that: In step (3), the edge cutting process adopts asymmetrical edge cutting, and the difference between the single-sided edge cutting amount on both sides is controlled between 0-20mm.

7. The production method for improving the edge quality of silicon steel according to claim 1, characterized in that: In step (3), the value of A is between 5 and 200 mm.

8. The production method for improving the edge quality of silicon steel according to claim 1, characterized in that: In step (5), the method for controlling the overlap amount is: D = 1.16 * h - 0.

68.

9. The production method for improving the edge quality of silicon steel according to claim 1, characterized in that: In step (6), the winding tension is controlled between 10-25 MPa.

10. A thin strip steel, characterized in that, The production process of the thin strip steel adopts the production method according to any one of claims 1-9.

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