Production method for continuously rolling high-grade silicon steel through pickling cold continuous rolling mill

Abstract

The invention discloses a production method for continuously rolling high-grade silicon steel through a pickling cold continuous rolling mill, and relates to the technical field of one-time hard coil rolling of high-grade silicon steel produced through a common pickling cold continuous rolling mill. Aiming at the problems of difficult machine welding, strip breakage of a withdrawal and straightening machine, incomplete acid washing, strip breakage of a welding seam of a rolling mill and the like of the steel in the production of a common acid rolling mill unit, stable production is realized through whole-flow process optimization. The method specifically comprises the steps that laser welding parameters are optimized, and clamp screws are fastened regularly; the extension rate of a withdrawal and straightening machine is 0.1-0.4%, a welding seam is empty, and a working roller is not put into use; controlling the gradient concentration of a pickling tank, adding an accelerant and optimizing a trimming process; the rolling mill adopts a smooth roll with a small roll diameter, the reduction rate is reasonably distributed, and the wave shape value is controlled to be less than 15I-U. The method can ensure that the weld joint is qualified, strip breakage is avoided, the pickling effect is good, qualified rolled hard coils are obtained, and the method is suitable for electrical steel core production.

Description

Technical Field

[0001] This invention relates to the field of coil technology, specifically to a production method for continuously rolling high-grade silicon steel using a pickling and cold continuous rolling mill. Background Technology

[0002] High-grade silicon steel faces numerous difficulties in production on ordinary pickling and rolling mills, such as welding difficulties, frequent strip breakage in the straightening machine, incomplete pickling in the pickling section, and frequent weld strip breakage in the rolling mill.

[0003] The purpose of this invention is to solve the problems of welding, strip breakage in the straightening machine, pickling difficulties, and frequent strip breakage of the weld seam in the rolling mill for high-grade silicon steel, and to produce qualified once-rolled hardened silicon steel coils for use in the production of electrical steel cores. The steel grade is MBRNQ00006, with a typical thickness of 2.3±0.1mm for hot-rolled feedstock and a rolling thickness of 0.63mm±0.018mm for hardened coils. Summary of the Invention

[0004] The purpose of this invention is to provide a method for producing high-grade silicon steel by continuous rolling in a pickling and cold rolling mill, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a production method for continuously rolling high-grade silicon steel using a pickling and cold rolling mill, characterized in that it includes welding, tension leveling, pickling and trimming, and rolling.

[0006] S1 Welding Process: The steel plate is welded using a laser welding machine with a laser power of 12000w, a welding speed of 3.0m / min, a gap of -0.35mm, a welding wire speed of 3.5m / min, a preheating current of 120A, and a postheating current of 150A.

[0007] S2 tension straightening treatment: The steel substrate is tension straightened using a tension straightening machine. The tension straightening elongation is controlled at 0.1~0.4%. Welds are not tension straightened if they pass through empty, and the working rollers of the tension straightening machine are removed and not used.

[0008] S3 Pickling and Edge Trimming: The steel coils that have undergone tension straightening are sequentially fed into pickling tanks #1, #2, and #3 for pickling. The HCl concentration range for pickling tank #1 is 160-200 g / L, for pickling tank #2 it is 120-160 g / L, and for pickling tank #3 it is 80-120 g / L. The temperature of each pickling tank is controlled at 85℃. After pickling, the steel plates are dried in a dryer at 130℃. The insertion depth of the upper roller of #7 CPC is adjusted from 120 mm to 90 mm. Edge trimmers are used to trim the edges of the steel plates. The steel plates are not wound up without trimming.

[0009] S4 mill rolling process: The rolling oil concentration of the emulsion is controlled at 2.2-2.8%, and the emulsion temperature is controlled at 58℃. There are a total of 10 work rolls (5 pairs) from the 1st to the 5th stands, all of which adopt the smooth roll mode. The work roll diameter is 390-410mm. The roughness of the 1st and 2nd work rolls is 0.9-1.0μm, the roughness of the 3rd work roll is 0.6-0.7μm, and the roughness of the 4th and 5th work rolls is 0.4-0.5μm. The reduction rate distribution of the 1st to 5th stands is 22%, 31%, 27%, 21.9%, and 13%, respectively. The downward stroke of the three-roll stabilizing roll at the mill entrance is increased from 140mm to 38mm, and the waviness value is controlled to be <15I-U.

[0010] Preferably, the high-grade silicon steel is MCGO-C1, with a silicon content of 3.05-3.25%.

[0011] Preferably, in step S1, the welding machine clamp screws are checked and tightened once every 3 hours. For welds that are poorly welded and have been welded more than 3 times, the affected part of the welder's heating process, including the beginning and end, is cut off before welding again.

[0012] Preferably, in step S3, for every 200t of silicon steel produced, 150kg of accelerator is added to the hydrochloric acid in the pickling tank.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0014] This invention discloses a method for producing high-grade silicon steel by continuous rolling in a pickling and cold rolling mill. This method solves the problems of welding, strip breakage in the straightening machine, pickling difficulties, and frequent strip breakage of the weld seam in the rolling mill for high-grade silicon steel, and produces qualified single-rolled hard silicon steel coils, which are used in the production of electrical steel cores. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the key equipment in the pickling section of the pickling line of the present invention;

[0016] Figure 2 This is a schematic diagram of key equipment in the acid rolling mill section of the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] This invention discloses a method for continuously rolling high-grade silicon steel using a pickling and cold rolling mill, specifically including the following production steps:

[0019] 1. Welding method: This patent uses a welding machine ( Figure 1 The No. 1 welding machine is a laser butt welding machine for pickling and cold continuous rolling, used for welding steel plates. Ordinary welding wire is used. Laser power: 12000W, welding speed: 3.0m / min, Gap: -0.35mm (compensated based on measured butt gap), wire speed: 3.5m / min, pre-heating current: 120A, post-heating current: 150A. If the weld is unsatisfactory, repeat the welding process more than 3 times, cutting off the affected portion from the welding machine's heating process before re-welding. During production, the welding machine clamp screws are checked and tightened every 3 hours to prevent accuracy drift. Purpose: Ordinary welding wire has a good welding promoting effect on high-grade silicon steel; the wire filling speed is greater than the welding speed, which is beneficial to improving the fusion performance of the filler wire to the strip steel in the weld.

[0020] 2. Control method of tension leveling machine: ( Figure 1 The 2-inch tension leveler uses an elongation rate controlled at 0.1-0.4%, with weld seams passing through without tension leveling. The working rolls of the tension leveler are removed and not used. This elongation rate effectively breaks down the phosphate layer during tension leveling, preventing the steel substrate from breaking, while significantly improving subsequent pickling for iron oxide removal. Keeping the working rolls of the tension leveler off eliminates the risk of cracks and strip breakage when sections with poor plate shape pass through.

[0021] 3. Pickling and trimming process: ( Figure 1 The pickling tanks consist of three sections: Tank #1 has an HCl concentration range of 160-200 g / L, Tank #2 has an HCl concentration range of 120-160 g / L, and Tank #3 has an HCl concentration range of 80-120 g / L. The target temperature for all tanks is controlled at 85℃. Based on production tonnage, 150 kg of accelerator is added to the hydrochloric acid in the pickling tanks for every 200 tons of grain-oriented silicon steel produced. Figure 1 The dryer (4-inch model) is used for drying at 130℃. Figure 1 The insertion depth of the upper roller of the 7#CPC (CPC No. 5) has been increased from 120mm to 90mm. Figure 1 The 6-inch edge-cutting shear is used to break up the edges instead of using edge-cutting coiling. By employing methods such as high concentration, high temperature, accelerators, high-temperature drying, and centering roller adjustment, the pickling effect is improved, and the temperature in the weld area is increased. Using the edge-cutting shear allows for smooth edge cutting, avoiding production interruptions caused by edge breakage during edge-cutting coiling.

[0022] 4. Rolling mill ( Figure 2 The process employs smooth roll rolling as follows: the rolling oil concentration in the emulsion is 2.2-2.8%, and the target temperature of the emulsion is 58℃. Figure 2The system comprises 10 work rolls (5 pairs, 1-5 sets), all in smooth roll configuration. The work roll diameter is a small diameter of 390-410 mm. The surface roughness of sets 1 and 2 is 0.9-1.0 μm, set 3 is 0.6-0.7 μm, and sets 4 and 5 are 0.4-0.5 μm. The reduction rates for sets 1-5 are 22%, 31%, 27%, 21.9%, and 13%, respectively. Figure 2 The downward stroke of the three-roll stabilizing roll at the inlet of the No. 7 mill was increased from 140mm to 38mm. The waviness value was controlled to be <15I-U. These measures aimed to reduce rolling force, minimize the load on 3-4 stands, reduce weld bends at the inlet, and lower the probability of weld breakage. These measures yielded good production results.

[0023] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for producing high-grade silicon steel by continuous rolling in a pickling and cold rolling mill, characterized in that: This includes welding, tension leveling, pickling and trimming, and rolling. S1 Welding Process: The steel plate is welded using a laser welding machine with a laser power of 12000w, a welding speed of 3.0m / min, a gap of -0.35mm, a welding wire speed of 3.5m / min, a preheating current of 120A, and a postheating current of 150A. S2 tension straightening treatment: The steel substrate is tension straightened using a tension straightening machine. The tension straightening elongation is controlled at 0.1~0.4%. Welds are not tension straightened if they pass through empty, and the working rollers of the tension straightening machine are removed and not used. S3 Pickling and Edge Trimming: The steel coils that have undergone tension straightening are sequentially fed into pickling tanks #1, #2, and #3 for pickling. The HCl concentration range for pickling tank #1 is 160-200 g / L, for pickling tank #2 it is 120-160 g / L, and for pickling tank #3 it is 80-120 g / L. The temperature of each pickling tank is controlled at 85℃. After pickling, the steel plates are dried in a dryer at 130℃. The insertion depth of the upper roller of #7 CPC is adjusted from 120 mm to 90 mm. Edge trimmers are used to trim the edges of the steel plates. The steel plates are not wound up without trimming. S4 mill rolling process: The rolling oil concentration of the emulsion is controlled at 2.2-2.8%, and the emulsion temperature is controlled at 58℃. There are a total of 10 work rolls (5 pairs) from the 1st to the 5th stands, all of which adopt the smooth roll mode. The work roll diameter is 390-410mm. The roughness of the 1st and 2nd work rolls is 0.9-1.0μm, the roughness of the 3rd work roll is 0.6-0.7μm, and the roughness of the 4th and 5th work rolls is 0.4-0.5μm. The reduction rate distribution of the 1st to 5th stands is 22%, 31%, 27%, 21.9%, and 13%, respectively. The downward stroke of the three-roll stabilizing roll at the mill entrance is increased from 140mm to 38mm, and the waviness value is controlled to be <15I-U.

2. The production method of high-grade silicon steel by continuous rolling in a pickling and cold rolling mill according to claim 1, characterized in that: The high-grade silicon steel is MCGO-C1, with a silicon content of 3.05-3.25%.

3. The production method of high-grade silicon steel by continuous rolling in a pickling and cold rolling mill according to claim 1, characterized in that: In step S1, the welding machine clamp screws are checked and tightened once every 3 hours. For welds that are poorly welded and have been welded more than 3 times, the affected part of the welder's heating is cut off at the beginning and end before welding again.

4. The production method of high-grade silicon steel by continuous rolling in a pickling and cold rolling mill according to claim 1, characterized in that: In step S3, for every 200 tons of silicon steel produced, 150 kg of accelerator is added to the hydrochloric acid in the pickling tank.

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