Rolling method for starting rolling of non-oriented silicon steel raw plate with 3.5~5% silicon and aluminum content in UCMW continuous rolling mill

Abstract

The present invention discloses a rolling method for starting rolling of raw plates of non-oriented silicon steel with a silicon-aluminum content of 3.5-5% by threading the strip on a UCMW continuous rolling mill. The present invention adopts a method of starting rolling by pressing down in succession, which is different from the traditional method of starting rolling by pressing down in succession on 5 stands at the same time. It reasonably sets the appropriate rolling process for stands 1 to 5#, which can effectively improve the starting success rate of raw plates of non-oriented silicon steel with a silicon-aluminum content of 3.5-5%, and quickly resume production after the strip breaks during rolling. By using the method of the present invention to start rolling by threading the raw plates, the difficulty of non-steady-state rolling of each stand can be greatly reduced, the fluctuation of the rolling force and tension of each stand can be reduced, and the strip breaks during rolling can be avoided, providing the prerequisite for the UCMW cold continuous rolling mill to mass-produce high-grade non-oriented silicon steel with a silicon-aluminum alloy content of 3.5-5%.

Description

Technical Field

[0001] The invention relates to the technical field of silicon steel raw plate strip rolling, and in particular to a rolling method for starting strip rolling of non-oriented silicon steel raw plate strip with a silicon-aluminum content of 3.5-5% produced by a UCMW continuous rolling mill. Background Art

[0002] High-grade non-oriented silicon steel is primarily used in the manufacture of large and medium-sized motors and generators. With the rapid development of the new energy vehicle industry, the market for steel used in new energy drive motors is growing, creating a strong demand for high-grade non-oriented silicon steel (with a silicon and aluminum content of 3.5% or more). Improving the production efficiency and reducing the cost per ton of non-oriented silicon steel with a silicon and aluminum content of 3.5% to 5% is crucial. Currently, non-oriented silicon steel with a silicon and aluminum content of 3.5% to 5% is primarily produced using reversing mills, which have low production efficiency and high costs. However, the traditional operating methods of the highly efficient and low-cost 5-stand UCMW cold tandem mill (with a work roll diameter range of 385 to 425 mm) are not capable of mass-producing this type of steel. The threading rolling process on a UCMW cold tandem mill is a non-steady-state rolling process. Traditionally, threading rolling on a tandem mill involves the simultaneous start-up of all five stands, with each stand dynamically pressing down. Once the rolling state transition conditions are met, steady-state rolling begins. This method of starting rolling by threading the original plate with 5 stands started simultaneously has a high success rate for steel strips with low alloy content. However, when the silicon-aluminum alloy content reaches 3.5-5% and the rolling force reaches more than 1,300 tons, the fluctuation of rolling force and tension can easily cause strip breakage, resulting in failure of threading and rolling. Summary of the Invention

[0003] To address the above-mentioned issues, the present invention provides a rolling method for the start-up rolling of non-oriented silicon steel raw sheets with a silicon and aluminum content of 3.5-5% on a UCMW continuous rolling mill. Through research, the present invention adopts a sequential reduction start-up rolling method, which differs from the traditional simultaneous reduction start-up rolling method for five stands. By rationally setting appropriate rolling processes for stands 1-5, the method effectively improves the start-up success rate of non-oriented silicon steel raw sheets with a silicon and aluminum content of 3.5-5%, and rapidly resumes production after a strip break during rolling.

[0004] In order to solve the above technical problems, the present invention is implemented through the following technical solutions:

[0005] A rolling method for producing non-oriented silicon steel raw plate with a silicon-aluminum content of 3.5-5% by a UCMW continuous rolling mill through strip threading and starting rolling, comprising:

[0006] S1. Select pickled non-oriented steel strip with a silicon and aluminum content of 3.5-5%;

[0007] S2. Put the steel strip into the electromagnetic heating furnace for heating. After the steel strip is heated, thread it until it is coiled and wrapped tightly.

[0008] S3, adopt the pass-by-pass original plate starting method, cancel the thickness automatic control module, and press down the 1~5# racks in sequence, as follows:

[0009] S31, put into operation 1# stand, reduce rate 30-40%, control rolling force 1200-1600×10KN, entrance unit tension 4.2-5.5×10N / mm 2 , winding unit tension 9.7~11×10N / mm 2 Among them, the 1# stand adopts a large reduction rate, mainly to crush the grains to a greater extent and refine the grains. Thin steel strips with coarse grains are very likely to develop edge cracks and breakage accidents during the rolling process of the rear stand. The coiling unit tension value is 9.7~11×10N / mm 2 The main reasons are: ① the total tension allowed by the coiler equipment capacity has reached the upper limit; ② the larger coiling tension can reduce the pressing load of the 1# stand and reduce the rolling force of the 1# stand;

[0010] After the steel strip of S32# stand passes through the roll gap of 2# stand (to ensure that the thickness of the steel strip does not change dramatically when 2# stand is pressed down, and the thickness of the steel strip does not suddenly change from the original plate thickness to the exit thickness of 1# stand, thus avoiding the drastic change of rolling force due to the drastic change of plate thickness and maintaining the stability of the steel strip between stands), it is put into 2# stand with a reduction rate of 35-45%, a rolling force controlled at 1100-1500×10KN, and a unit tension of 12-14.8×10N / mm between 1# and 2# stands. 2 , winding unit tension 10~11.7×10N / mm 2 ; Among them, the winding unit tension value is 10~11.7×10N / mm 2 The main reason is: the larger coiling tension can reduce the pressing load of the 2# stand and reduce the rolling force of the 2# stand;

[0011] After the steel strip of S33 and 2# stands passes through the roll gap of 3# stand (to ensure that the thickness of the steel strip does not change dramatically when 3# stand is pressed down, and the thickness of the steel strip does not suddenly change from the original plate thickness to the exit thickness of 2# stand, thus avoiding the drastic change of rolling force due to the drastic change of plate thickness and maintaining the stability of the steel strip between stands), it is put into 3# stand with a reduction rate of 25-32%, a rolling force control of 900-1400×10 kN, and a unit tension of 13-16×10 N / mm for 2# to 3# stands. 2 , winding unit tension 9~11×10N / mm 2 Among them, after the 3# frame is pressed down, the thickness of the steel strip is reduced to a certain extent. It is necessary to ensure the stability of the steel strip by reducing the coiling unit tension to prevent the steel strip from tearing due to excessive coiling tension.

[0012] After the steel strip of S34 and 3# stands passes through the roll gap of 4# stand (to ensure that the thickness of the steel strip does not change dramatically when 4# stand is pressed down, and the thickness of the steel strip does not suddenly change from the original plate thickness to the exit thickness of 3# stand, thus avoiding the drastic change of rolling force due to the drastic change of plate thickness and maintaining the stability of the steel strip between stands), it is put into 4# stand with a reduction rate of 18-28%, a rolling force controlled at 850-1350×10KN, and a unit tension of 14-17×10N / mm for 3# to 4# stands. 2 , winding unit tension 8~10.5×10N / mm 2 Among them, after the 4# frame is pressed down, the thickness of the steel strip is further reduced, and it is necessary to further reduce the coiling unit tension to ensure the stability of the steel strip and prevent the steel strip from tearing due to excessive coiling tension;

[0013] After the steel strip of S35 and 4# stands passes through the roll gap of 5# stand (to ensure that the thickness of the steel strip does not change dramatically when 5# stand is pressed down, and the thickness of the steel strip does not suddenly change from the original plate thickness to the exit thickness of 4# stand, thus avoiding the drastic change of rolling force due to the drastic change of plate thickness and maintaining the stability of the steel strip between stands), it is put into 5# stand with a reduction rate of 18-25%, a rolling force control of 800-1300×10KN, and a unit tension of 14.5-18×10N / mm for 4# to 5# stands. 2 , winding unit tension 7~10×10N / mm 2 Among them, after the 5# frame is pressed down, the thickness of the steel strip is further reduced, and it is necessary to further reduce the coiling unit tension to ensure the stability of the steel strip and prevent the steel strip from tearing due to excessive coiling tension;

[0014] After the S36 and 5# stand steel strip rolling lines are wrapped into the coiler, the machine is shut down and the thickness automatic control module is restored before resuming rolling production.

[0015] Preferably, in step S1, the thickness of the steel strip is 1.8-2.4 mm.

[0016] Preferably, in step S2, the electromagnetic heating furnace operates at a temperature of 80-100°C. Heating the steel strip in the electromagnetic heating furnace can reduce the yield strength and tensile strength of the steel strip. This can effectively reduce the rolling load and rolling force of the rolling mill, and reduce the probability of bending and breaking during the threading and coiling process. If the heating furnace temperature is too high, the electricity consumption per ton of steel will increase, the aging of the heating furnace cables will accelerate, and the cost per ton of steel will increase as well as the equipment failure rate. If the heating furnace temperature is too low, the purpose of reducing the rolling load and the incidence of bending and breaking will not be achieved.

[0017] Preferably, in step S3, the total reduction ratio of stands 1 to 5 is 70% to 90%. The reduction ratio set in steps S31 to S35 refers to the thickness before rolling - the thickness after rolling) / the thickness before rolling after rolling of each stand in each step, and the total reduction ratio refers to the thickness before rolling of stand 1 - the thickness after rolling of stand 5 / the thickness before rolling of stand 1).

[0018] Preferably, in step S3, the diameter of the work rolls of stands 1 to 5 is 385 to 410 mm, and the surface roughness of the work rolls is 0.2 to 0.4 μm. The work rolls of the 5-stand continuous rolling mill have a diameter of 385 to 425 mm. Using small-diameter rolls can effectively reduce rolling loads and rolling forces. Similarly, the surface roughness of general-purpose work rolls ranges from 0.2 to 0.7 μm. Using work rolls with a small roughness can effectively reduce rolling forces.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] By using the method of the present invention to start rolling by threading the raw plate, the difficulty of non-steady-state rolling of each stand can be greatly reduced, the fluctuation of rolling force and tension of each stand can be reduced, and strip breakage during rolling can be avoided, thereby providing the prerequisite for the UCMW cold rolling mill to mass-produce non-oriented high-grade silicon-aluminum alloy with a content of 3.5-5%. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the technical solutions of the present invention, preferred embodiments of the present invention are described below in conjunction with specific examples, but this should not be construed as limiting this patent.

[0022] Unless otherwise specified, the experimental methods or test methods described in the following examples are all conventional methods; the reagents and materials described are all obtained from conventional commercial channels or prepared by conventional methods unless otherwise specified.

[0023] Example 1

[0024] A pickling continuous rolling mill is used to produce normalized non-oriented silicon steel coils with a silicon and aluminum content of 3.8% and a plate width of 1100 mm. The finished product thickness is 0.35 mm. The specific steps for starting rolling after threading the raw plate are as follows:

[0025] (1) The smelting, continuous casting, hot rolling and normalizing pickling units use conventional non-oriented processes, and the thickness of silicon steel before cold rolling is 2.2 mm;

[0026] (2) The working roll diameter is 385 mm and the working roll surface roughness is 0.2 μm;

[0027] (3) Put the steel strip into the electromagnetic heating furnace, control the temperature at 80°C, and pass the steel strip through the heating zone until it is coiled and wrapped tightly;

[0028] (4) Using the pass-by-pass original plate starting method, canceling the thickness automatic control module (AGC), and pressing down the 1 to 5# racks in sequence;

[0029] 4.1) Put into operation the 1# stand, with a reduction rate of 35.5%, a rolling force of 1340×10 kN, and an inlet unit tension of 5.18×10 N / mm. 2 , winding unit tension 11.01×10N / mm 2 ;

[0030] 4.2) After the rolling line of the steel strip of the 1# stand passes through the roll gap of the 2# stand, it is put into the 2# stand with a reduction rate of 38.5%, a rolling force controlled at 1200×10KN, and a unit tension of 1~2# stands of 13.2×10N / mm. 2 , winding unit tension 10.63×10N / mm 2 ;

[0031] 4.3) After the rolling line of the steel strip of the 2# stand passes through the roll gap of the 3# stand, it is put into the 3# stand with a reduction rate of 29.5%, a rolling force controlled at 1022×10KN, and a unit tension of 14.62×10N / mm between the 2# and 3# stands. 2 , winding unit tension 10.53×10N / mm 2 ;

[0032] 4.4) After the rolling line of the steel strip of the 3# stand passes through the roll gap of the 4# stand, it is put into the 4# stand with a reduction rate of 24.6%, a rolling force controlled at 870×10 kN, and a unit tension of 15.64×10 N / mm between the 3# and 4# stands. 2 , winding unit tension 9.85×10N / mm 2 ;

[0033] 4.5) After the rolling line of the steel strip of the 4# stand passes through the roll gap of the 5# stand, it is put into the 5# stand with a reduction rate of 20.9%, a rolling force controlled at 850×10KN, and a unit tension of 16.21×10N / mm between the 4# and 5# stands. 2 , winding unit tension 9.01×10N / mm 2 ;

[0034] 4.6) After the 5# stand steel strip rolling line is wrapped into the coiler, the machine is shut down and the thickness automatic control module (AGC) is restored before resuming rolling production.

[0035] The final product of this example was successfully threaded and rolled without any breakage.

[0036] Example 2

[0037] A pickling continuous rolling mill is used to produce normalized non-oriented silicon steel coils with a silicon and aluminum content of 4.81% and a plate width of 1250mm. The finished product thickness is 0.35mm. The specific steps for starting rolling after threading the raw plate are as follows:

[0038] (1) The smelting, continuous casting, hot rolling and normalizing pickling units use conventional non-oriented processes, and the thickness of silicon steel before cold rolling is 2.2 mm;

[0039] (2) The working roll diameter is 400 mm and the working roll surface roughness is 0.3 μm;

[0040] (3) Put the steel strip into the electromagnetic heating furnace, control the temperature at 100°C, and pass the steel strip through the heating zone until it is coiled and wrapped tightly;

[0041] (4) Using the pass-by-pass original plate starting method, canceling the thickness automatic control module (AGC), and pressing down the 1 to 5# racks in sequence;

[0042] 4.1) Put into operation the 1# stand, the reduction rate is 35.5%, the rolling force is controlled at 1460×10 kN, and the entrance unit tension is 4.92×10 N / mm 2 , winding unit tension 10.6×10N / mm 2 ;

[0043] 4.2) After the rolling line of the steel strip of the 1# stand passes through the roll gap of the 2# stand, it is put into the 2# stand with a reduction rate of 38.5%, a rolling force controlled at 1350×10KN, and a unit tension of 1~2# stands of 13.4×10N / mm. 2 , winding unit tension 10.63×10N / mm 2 ;

[0044] 4.3) After the rolling line of the steel strip of the 2# stand passes through the roll gap of the 3# stand, it is put into the 3# stand with a reduction rate of 29.5%, a rolling force controlled at 1022×10KN, and a unit tension of 15×10N / mm between the 2# and 3# stands. 2 , winding unit tension 9.74×10N / mm 2 ;

[0045] 4.4) After the rolling line of the steel strip of the 3# stand passes through the roll gap of the 4# stand, it is put into the 4# stand with a reduction rate of 24.6%, a rolling force controlled at 870×10KN, and a unit tension of 15.9×10N / mm between the 3# and 4# stands. 2 , winding unit tension 8.68×10N / mm 2 ;

[0046] 4.5) After the rolling line of the steel strip of the 4# stand passes through the roll gap of the 5# stand, it is put into the 5# stand with a reduction rate of 20.9%, a rolling force controlled at 850×10KN, and a unit tension of 16.8×10N / mm between the 4# and 5# stands. 2, winding unit tension 7.8×10N / mm 2 ;

[0047] 4.6) After the 5# stand steel strip rolling line is wrapped into the coiler, the machine is shut down and the thickness automatic control module (AGC) is restored before resuming rolling production.

[0048] The final product of this example was successfully threaded and rolled without any breakage.

[0049] Example 3

[0050] A pickling continuous rolling mill is used to produce normalized non-oriented silicon steel coils with a silicon and aluminum content of 3.6% and a plate width of 1200 mm. The finished product thickness is 0.35 mm. The specific steps for starting rolling after threading the raw plate are as follows:

[0051] (1) The smelting, continuous casting, hot rolling and normalizing pickling units use conventional non-oriented processes, and the thickness of silicon steel before cold rolling is 2.2 mm;

[0052] (2) The working roll diameter is 392 mm and the working roll surface roughness is 0.2 μm;

[0053] (3) Put the steel strip into the electromagnetic heating furnace, control the temperature at 90°C, and pass the steel strip through the heating zone until it is coiled and wrapped tightly;

[0054] (4) Using the pass-by-pass original plate starting method, cancel the thickness automatic control module (AGC), and press down the 1 to 5# racks in sequence;

[0055] 4.1) Put into operation the 1# stand, with a reduction rate of 35%, a rolling force of 1400×10KN, and an inlet unit tension of 4.5×10N / mm. 2 , winding unit tension 10.2×10N / mm 2 ;

[0056] 4.2) After the rolling line of the steel strip of the 1# stand passes through the roll gap of the 2# stand, it is put into the 2# stand with a reduction rate of 38.7%, a rolling force controlled at 1310×10 kN, and a unit tension of 1~2# stands of 12.7×10 N / mm. 2 , winding unit tension 10.43×10N / mm 2 ;

[0057] 4.3) After the rolling line of the steel strip of the 2# stand passes through the roll gap of the 3# stand, it is put into the 3# stand with a reduction rate of 28%, a rolling force controlled at 1004×10KN, and a unit tension of 14.2×10N / mm between the 2# and 3# stands. 2 , winding unit tension 9.51×10N / mm 2 ;

[0058] 4.4) After the rolling line of the steel strip of the 3# stand passes through the roll gap of the 4# stand, it is put into the 4# stand with a reduction rate of 23.2%, a rolling force controlled at 860×10 kN, and a unit tension of 15.9×10 N / mm between the 3# and 4# stands. 2 , winding unit tension 8.2×10N / mm 2 ;

[0059] 4.5) After the rolling line of the steel strip of the 4# stand passes through the roll gap of the 5# stand, it is put into the 5# stand with a reduction rate of 19.8%, a rolling force controlled at 820×10KN, and a unit tension of 14.9×10N / mm between the 4# and 5# stands. 2 , winding unit tension 7.3×10N / mm 2 ;

[0060] 4.6) After the 5# stand steel strip rolling line is wrapped into the coiler, the machine is shut down and the thickness automatic control module (AGC) is restored before resuming rolling production.

[0061] The final product of this example was successfully threaded and rolled without any breakage.

[0062] Comparative Example 1

[0063] The only difference between Comparative Example 1 and Example 1 is that in step (3), the temperature of the electromagnetic heating furnace is controlled at 60°C.

[0064] The steel strip of this comparative example was bent and broken during the strip threading and coiling process.

[0065] Comparative Example 2

[0066] The only difference between Comparative Example 2 and Example 1 is that in step (4.1), rack 1# is put into use and the reduction rate is 20%.

[0067] The steel strip of this comparative example suffered from edge cracking and strip breakage during the rolling process.

[0068] Comparative Example 3

[0069] The only difference between Comparative Example 3 and Example 1 is that in step (4.2), the rolling line of the steel strip of the 1# stand does not pass through the roll gap of the 2# stand, that is, it is put into the 2# stand.

[0070] The steel strip of this comparative example was broken at the location where the thickness varied.

[0071] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be construed as limiting the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. Persons skilled in the art will appreciate that improvements and modifications may be made without departing from the spirit and scope of the present invention, and such improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A rolling method for producing non-oriented silicon steel raw plate with silicon and aluminum content of 3.5-5% by strip threading and starting rolling on a UCMW continuous rolling mill, characterized in that: include: S1. Select pickled non-oriented steel strip with a silicon and aluminum content of 3.5-5%; S2. Put the steel strip into the electromagnetic heating furnace for heating. After the steel strip is heated, thread it until it is coiled and wrapped tightly. S3, adopt the pass-by-pass original plate starting method, cancel the thickness automatic control module, and press down the 1~5# racks in sequence, as follows: S31, put into 1# stand, reduce rate 30-40%, control rolling force 1200-1600×10KN, entrance unit tension 4.2-5.5×10N / mm 2 , winding unit tension 9.7~11×10N / mm 2 ; S32, the rolling line of the steel strip of the 1# stand passes through the roll gap of the 2# stand and is put into the 2# stand with a reduction rate of 35-45%, a rolling force controlled at 1100-1500×10KN, and a unit tension of 1-2# stands of 12-14.8×10N / mm. 2 , winding unit tension 10~11.7×10N / mm 2 ; The S33 and 2# stand steel strips are rolled through the roll gap of the 3# stand and then put into the 3# stand with a reduction rate of 25-32%, a rolling force controlled at 900-1400×10KN, and a unit tension of 13-16×10N / mm for the 2# to 3# stands. 2 , winding unit tension 9~11×10N / mm 2 ; The S34, 3# stand steel strip rolling line passes through the 4# stand roll gap and is put into the 4# stand with a reduction rate of 18-28%, a rolling force controlled at 850-1350×10KN, and a unit tension of 14-17×10N / mm for 3# to 4# stands. 2 , winding unit tension 8~10.5×10N / mm 2 ; The rolling line of the S35 and 4# stand steel strips passes through the roll gap of the 5# stand and is put into the 5# stand with a reduction rate of 18-25%, a rolling force controlled at 800-1300×10KN, and a unit tension of 14.5-18×10N / mm for the 4-5# stands. 2 , winding unit tension 7~10×10N / mm 2 ; After the S36 and 5# stand steel strip rolling lines are wrapped into the coiler, the machine is shut down and the thickness automatic control module is restored before resuming rolling production.

2. The rolling method for producing non-oriented silicon steel raw plate with silicon and aluminum content of 3.5-5% by strip threading and starting rolling on a UCMW continuous rolling mill according to claim 1, characterized in that: In step S1, the thickness of the steel strip is 1.8 to 2.4 mm.

3. The rolling method for producing non-oriented silicon steel raw plate with silicon and aluminum content of 3.5-5% by strip threading and starting rolling on a UCMW continuous rolling mill according to claim 1, characterized in that: In step S2, the electromagnetic heating furnace operates at a temperature of 80-100°C.

4. The rolling method for producing non-oriented silicon steel raw plate with silicon and aluminum content of 3.5-5% by strip threading and starting rolling on a UCMW continuous rolling mill according to claim 1, characterized in that: In step S3, the total reduction ratio of the 1# to 5# frames is 70% to 90%.

5. The rolling method for producing non-oriented silicon steel raw plate with silicon and aluminum content of 3.5-5% by strip threading and starting rolling on a UCMW continuous rolling mill according to claim 1, characterized in that: In step S3, the diameter of the working rolls of the 1# to 5# frames is 385-410 mm, and the surface roughness of the working rolls is 0.2-0.4 μm.