Welding method for high-silicon-aluminum non-oriented silicon steel hot rolled plate

Abstract

The invention relates to the technical field of welding of non-oriented silicon steel hot-rolled plates, in particular to a welding method of a high-silicon-aluminum non-oriented silicon steel hot-rolled plate. (1) ensuring that the surface temperature of a steel plate is more than or equal to 50 DEG C during welding; (2) the gap between the abutted seams is controlled to range from 0.03 mm to 0.06 mm; (3) the welding speed is controlled to range from 4.60 m / min to 5.50 m / min; 4) negative defocusing is adopted; (5) the annealing current is controlled to be 170-190 A; and 6) if the single-side difference of the width specifications of the steel plate before and after the welding seam is not less than 50mm, performing edge digging treatment on the welding seam. The welding quality of the high-silicon-aluminum non-oriented silicon steel hot-rolled plate can be effectively improved only through welding process control without a special production line, strip breakage at a welding seam is reduced, and smooth production is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of welding non-oriented silicon steel hot-rolled plates, in particular to a welding method for high-silicon-aluminum non-oriented silicon steel hot-rolled plates. Background Art

[0002] Non-oriented silicon steel is an important metal functional soft magnetic material. With the development of the new energy vehicle industry, the demand for non-oriented silicon steel for drive motors is also increasing. Due to the complex operating conditions of new energy vehicle drive motors, the medium and low frequency electromagnetic properties of non-oriented silicon steel are very high, so the composition is designed with high silicon aluminum. However, high silicon aluminum non-oriented silicon steel must undergo normalization heat treatment during industrial production. The normalization unit is a continuous production unit, and the hot-rolled plate needs to be connected end to end. If the welding quality is poor, on the one hand, if re-welding occurs, the process section will slow down, the organization will be uneven, and the subsequent cold rolling and finished product performance will be affected; on the other hand, if the weld breaks after normalization, the steel strip in the furnace will be scrapped, the yield rate will be reduced, the labor intensity will increase, and the cost will increase. Therefore, ensuring good weld quality and improving the weld pass rate are effective guarantees for stabilizing the normalization production of high silicon aluminum non-oriented silicon steel. However, the existing welding method is not suitable for welding high silicon aluminum non-oriented silicon steel hot-rolled plates, resulting in poor welding quality and easy breakage at the weld.

[0003] The Chinese patent document with publication number CN110936103A discloses "a laser welding method for hot-rolled high-silicon steel plates", which mainly adopts laser welding technology, assisted by preheating, filling stainless steel welding wire and post-annealing means to reduce the weld break rate and improve the weld strength. This method is only applicable to production lines with preheating and post-annealing. The Chinese patent with publication number CN112139645B discloses "a narrow lap rolling seam welding method for high-silicon thin-gauge oriented silicon steel", which is not applicable to hot-rolled plates with a thickness of 2.0 to 2.3 mm. The Chinese patent with publication number CN106041305B discloses "a laser welding method for high-silicon steel", which can achieve good results, but is only applicable to production lines with preheating and post-welding insulation devices. The Chinese patent with announcement number CN111299830B discloses "a high silicon steel laser welding method", which can achieve good results, reduce costs and save raw materials, but is only applicable to production lines with laser welding equipment and requires gas protection and heat preservation treatment. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the present invention provides a high-silicon-aluminum non-oriented silicon steel hot-rolled plate welding method, which does not require a special production line. Only through welding process control, the welding quality of high-silicon-aluminum non-oriented silicon steel hot-rolled plates can be effectively improved, the breakage at the weld can be reduced, and smooth production can be ensured.

[0005] To achieve the above object, the present invention is implemented by the following technical solutions:

[0006] A welding method for hot-rolled high-silicon-aluminum non-oriented silicon steel sheets, wherein the mass percentage content of Si + Al in the hot-rolled high-silicon-aluminum non-oriented silicon steel sheets is greater than 4.0%, the thickness of the hot-rolled high-silicon-aluminum non-oriented silicon steel sheets is 2.0 - 2.3 mm, and the width is 920 - 1200 mm.

[0007] Specifically as follows:

[0008] 1) Ensure that the surface temperature of the steel sheet during welding is ≥ 50 °C;

[0009] 2) Control the butt joint gap to be 0.03 - 0.06 mm;

[0010] 3) Control the welding speed to be 4.60 - 5.50 m / min;

[0011] 4) Adopt negative defocus;

[0012] 5) Control the annealing current to be 170 - 190 A;

[0013] 6) If the unilateral difference in the width specifications of the steel sheets before and after the weld is ≥ 50 mm, perform edge cutting treatment at the weld.

[0014] Further, in 1), ensure that the surface temperature of the steel sheet during welding is 55 - 90 °C.

[0015] Further, in 1), ensure that the surface temperature of the steel sheet during welding is 55 - 70 °C.

[0016] Further, in 2), control the butt joint gap to be 0.045 - 0.055 mm.

[0017] Further, in 2), control the butt joint gap to be 0.046 - 0.054 mm.

[0018] Further, in 3), control the welding speed to be 4.90 - 5.50 m / min.

[0019] Further, in 3), control the welding speed to be 4.95 - 5.50 m / min.

[0020] Further, in 5), control the annealing current to be 174 - 185 A.

[0021] Further, in 5), control the annealing current to be 174 - 183 A.

[0022] Further, the mass percentage content of Si + Al in the hot-rolled high-silicon-aluminum non-oriented silicon steel sheets is 4.08% - 4.3%.

[0023] Compared with the existing methods, the beneficial effects of the present invention are:

[0024] 1. The present invention controls the seam gap to be 0.03 - 0.06 mm. Since the grains of high-silicon-aluminum non-oriented silicon steel grow and the crystal lattice becomes loose after normalization treatment, the smaller the seam gap, the better the welding molten pool effect. It can effectively increase the welding amount between the front and rear plates and improve the weld strength.

[0025] 2. The present invention controls the welding speed to be 4.60 - 5.50 m / min. By increasing the welding speed, the present invention increases the molten pool amount of the steel strip, reduces the nodulation of the laser nozzle, makes the weld more plump and smooth, and the cupping test effect is more ideal, reducing the influence of welding residual stress on the weld quality.

[0026] 3. The high-silicon-aluminum composition system requires a relatively large penetration depth. Since the welding of high-silicon-aluminum non-oriented silicon steel plates needs to increase the penetration depth of the lower surface of the weld to avoid excessive influence of residual stress on the base material after welding, the present invention significantly improves the weld passing rate by using negative defocus.

[0027] 4. The present invention controls the annealing current to be 170 - 190 A, effectively improving the yield strength and tensile strength of the welding area. Since local instantaneous plastic deformation and changes in the microstructure occur during the welding of high-silicon-aluminum non-oriented silicon steel plates, residual stress is generated during the welding process. Post-welding annealing can affect the weld quality and relieve the increase in residual stress generated inside due to the rapid cooling at the moment of welding completion, especially at a relatively low temperature in the welding area. It can meet the requirements of industrial mass production under conditions such as high tension and high-temperature heating.

[0028] In summary, the present invention does not require a special production line. Only through welding process control, it can effectively improve the welding quality of high-silicon-aluminum non-oriented silicon steel hot-rolled plates, reduce the breakage of the steel strip at the weld, and ensure the smooth progress of production. Specific Embodiments

[0029] The present invention discloses a welding method for high-silicon-aluminum non-oriented silicon steel hot-rolled plates. Those skilled in the art can draw on the content of this article and appropriately modify the process parameters to achieve it. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are all considered to be included in the present invention. The method and application of the present invention have been described through preferred embodiments. Relevant personnel can obviously make changes or appropriate alterations and combinations to the methods and applications described herein without departing from the content, spirit, and scope of the present invention to implement and apply the technology of the present invention.

[0030] A welding method for hot-rolled high-silicon-aluminum non-oriented silicon steel sheets, which is applicable to the production of hot-rolled sheets for cold-rolled non-oriented silicon steel with a mass percentage content of (Si + Al) greater than 4.0%. The thickness of the hot-rolled sheets for cold-rolled non-oriented silicon steel is 2.0 - 2.3 mm, and the width is 920 - 1200 mm. Starting from the welding process, by continuously adjusting the process parameters and through comparative analysis, a welding control method suitable for hot-rolled high-silicon-aluminum non-oriented silicon steel sheets has been summarized, effectively improving the weld strength and meeting the normalizing high-temperature heating and process of high-silicon-aluminum steel.

[0031] The above-mentioned welding method for hot-rolled high-silicon-aluminum non-oriented silicon steel sheets is as follows:

[0032] 1. After the coiler of the normalizing unit is opened, a preheating device is added to ensure that the surface temperature of the steel sheet during welding is ≥ 50 °C.

[0033] 2. Seam gap: 0.03 - 0.06 mm.

[0034] Since the grains of high-silicon-aluminum non-oriented silicon steel grow and the crystal lattice becomes loose after normalizing treatment, the smaller the seam gap, the better the welding molten pool effect. It can effectively increase the welding amount of the front and rear plates and improve the weld strength.

[0035] 3. Welding speed: 4.60 - 5.50 m / min.

[0036] Increasing the welding speed can increase the molten pool amount of the steel strip, reduce the nodulation of the laser nozzle, make the weld more plump and smooth, and the cupping test effect is more ideal. It can also reduce the influence of welding residual stress on the weld quality.

[0037] 4. Use negative defocus.

[0038] The high-silicon-aluminum composition system requires a relatively large penetration depth. Since the welding of high-silicon-aluminum non-oriented silicon steel sheets needs to increase the penetration depth of the lower surface of the weld to avoid excessive residual stress after welding affecting the base metal, negative defocus is used, which can significantly improve the weld passing rate.

[0039] 5. Annealing current: 170 - 190 A.

[0040] It can effectively improve the yield strength and tensile strength of the welding area. Due to the local instantaneous plastic deformation and the change of the microstructure of the high-silicon-aluminum non-oriented silicon steel sheet during welding, residual stress is generated during welding. Post-weld annealing can affect the weld quality and relieve the increase of residual stress generated inside due to the instantaneous cooling after welding, especially when the temperature of the welding area is relatively low. It can meet the industrial large-scale production under conditions such as large tension and high-temperature heating.

[0041] 6. When the unilateral difference in the width specifications of the steel sheets before and after the weld is ≥ 50 mm, edge trimming treatment is carried out at the weld.

[0042] Example:

[0043] In the embodiments of the present invention, the thickness and main components of the hot-rolled sheet are shown in Table 1, the main welding processes of each embodiment are shown in Table 2, and the technical effects of the embodiments are shown in Table 3.

[0044] Table 1 Thickness and Main Components of the Hot-Rolled Sheet in the Embodiments

[0045] Components Hot-rolled plate thickness Si + Als, % Example 1 2.0 mm 4.08 Example 2 2.2 mm 4.15 Example 3 2.3 mm 4.23

[0046] Table 2 Main Welding Processes

[0047] Steel plate temperature during welding Butt joint gap Welding speed Annealing current Example 1 56℃ 0.048 mm 5.50 m / min 174A Example 2 60℃ 0.051 mm 4.95 m / min 180A Example 3 55℃ 0.049 mm 5.00 m / min 182A

[0048] Table 3 Embodiment Effects

[0049] Weld quality Weld breakage condition Example 1 Good None Example 2 Good None Example 3 Good None

[0050] As shown in the above table, the present invention does not require a special production line. Only by controlling the welding process can the welding quality of the hot-rolled sheet of high-silicon aluminum non-oriented silicon steel be effectively improved, no breakage of the strip at the weld seam be achieved, and the smooth progress of production be ensured.

[0051] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and all should be covered within the protection scope of the present invention.

Claims

1. A method for welding high silicon aluminum non-oriented silicon steel hot rolled plate, characterized in that: The mass percentage of Si+Al in the high silicon aluminum non-oriented silicon steel hot rolled plate is greater than 4.0%, and the thickness of the high silicon aluminum non-oriented silicon steel hot rolled plate is 2.0-2.3 mm, and the width is 920-1200 mm; The details are as follows: 1) Ensure that the surface temperature of the steel plate during welding is ≥50℃; 2) Control the gap between the joints to 0.03 and 0.06 mm; 3) Control the welding speed to 4.60~5.50m / min; 4) Use negative defocus; 5) Control the annealing current to 170-190A; 6) If the width of the steel plate before and after the weld differs by ≥50mm on one side, the weld should be edge-cut.

2. The method for welding high silicon aluminum non-oriented silicon steel hot rolled plate according to claim 1, characterized in that: 1) Ensure that the surface temperature of the steel plate is 55-90°C during welding.

3. The method for welding high silicon aluminum non-oriented silicon steel hot rolled plate according to claim 1, characterized in that: 1) Ensure that the surface temperature of the steel plate is 55-70°C during welding.

4. The method for welding high silicon aluminum non-oriented silicon steel hot rolled plate according to claim 1, characterized in that: 2) The gap between the joints is controlled to be 0.045 to 0.055 mm.

5. The method for welding high silicon aluminum non-oriented silicon steel hot rolled plate according to claim 1, characterized in that: 2) The gap between the joints is controlled to be 0.046 to 0.054 mm.

6. The method for welding high silicon aluminum non-oriented silicon steel hot rolled plate according to claim 1, characterized in that: 3), the welding speed is controlled to be 4.90~5.50m / min.

7. The method for welding high silicon aluminum non-oriented silicon steel hot rolled plate according to claim 1, characterized in that: 3), the welding speed is controlled to be 4.95~5.50m / min.

8. The method for welding high silicon aluminum non-oriented silicon steel hot rolled plate according to claim 1, characterized in that: 5), the annealing current is controlled to be 174-185A.

9. The method for welding high silicon aluminum non-oriented silicon steel hot rolled plate according to claim 1, characterized in that: 5), the annealing current is controlled to be 174-183A.

10. The method for welding high silicon aluminum non-oriented silicon steel hot rolled plate according to claim 1, characterized in that: The mass percentage content of Si+Al in the high silicon aluminum non-oriented silicon steel hot rolled plate is 4.08% to 4.3%.