Method for annealing and pickling SUS410L cold-rolled strip steel

Abstract

The invention belongs to the field of strip steel pickling, and relates to a method for annealing and pickling SUS410L cold-rolled strip steel. The stable performance of the SUS410L strip steel is ensured, the processing rate of a continuous rolling support switching single rack is reduced, and in addition, the production efficiency is improved on the premise that the performance is ensured. According to the technical scheme, the method comprises the steps that on-line annealing is conducted on SUS410L cold-rolled strip steel, five zones are added compared with seven zones of a first hot line, the furnace temperature is 825-865 DEG C, the furnace temperature of the first three zones is set to be rapidly increased to the annealing temperature, the furnace temperature of the last nine zones is kept unchanged, and the annealing time is prolonged; scale breaking is conducted on the SUS410L cold-rolled strip steel, scale breaking is controlled according to a tension mode, the tension is set to be 340 KN, and shot blasting treatment is conducted after scale breaking; the SUS410L cold-rolled strip steel is subjected to sulfuric acid pickling; the SUS410L cold-rolled strip steel is subjected to mixed acid pickling, nitric acid and hydrofluoric acid are used for mixed acid pickling, two-stage mixed acid is used, the nitric acid concentration is 60-100 g / l, the hydrofluoric acid concentration is 0-5 g / l, the temperature is controlled to be 40-50 DEG C, and the iron ion concentration is controlled to be within 40 g / l.

Description

Technical Field

[0001] The invention belongs to the field of strip steel pickling and relates to a method for annealing and pickling of SUS410L cold-rolled strip steel. Background Art

[0002] SUS410L stainless steel is mostly used for container panels, and has high requirements for performance, plate shape and thickness. In order to ensure product quality, the production process of "bell furnace annealing + hot wire pickling + rolling + cold wire annealing and pickling" has been adopted. However, bell furnace annealing not only has a long production cycle, but also has high production costs. The edge annealing print defects also affect the qualified rate of finished products and the delivery cycle. In order to save production costs, shorten the manufacturing cycle, and reduce annealing print defects, bell furnace annealing was cancelled, and the process became "hot wire annealing and pickling + rolling + cold wire annealing and pickling". However, after a period of production, it was found that the production efficiency of other hot lines was slow and could not meet the needs of large-scale continuous rolling production. New production methods need to be studied. In addition, some coils with fluctuating plate temperatures need to be switched from continuous rolling process to single-frame process. The surface and performance of SUS410L produced by single-frame are different from those of SUS410L produced by continuous rolling, which affects the continuity of the surface and the uniformity of performance.

[0003] After analysis, it is mainly because the performance of SUS410L strip is more sensitive to the fluctuation of annealing plate temperature during hot line continuous annealing than other steel grades. A slight change in temperature will cause a large fluctuation in the elongation of the strip, affecting the safety of continuous rolling production. Therefore, it is necessary to find a method for annealing and pickling SUS410L cold-rolled strip. Summary of the invention

[0004] In order to overcome the defects in the above-mentioned related technologies, the present invention proposes a method for annealing and pickling of SUS410L cold-rolled strip steel, which ensures the stable performance of SUS410L strip steel, reduces the single-frame process rate of continuous rolling support switching, and improves production efficiency while ensuring performance.

[0005] To achieve the above technical purpose, the method for annealing and pickling SUS410L cold-rolled strip steel of the present invention comprises: performing online annealing on SUS410L cold-rolled strip steel, adding 5 zones compared with the 7 zones of the previous 1# hot line, the furnace temperature is 825-865°C, the furnace temperature of the first 3 zones is set to be quickly raised to the annealing temperature, and the furnace temperature of the last 9 zones is kept unchanged to increase the annealing time; Scaling of SUS410L cold-rolled strip steel is performed. The scale breaking is controlled according to the tension mode. The tension is set to 340KN. Shot blasting is performed after scale breaking. The SUS410L cold-rolled strip was pickled with sulfuric acid, the sulfuric acid concentration was 280 g / l, the temperature was 80 °C, and the iron ion concentration was controlled within 45 g / l; The SUS410L cold-rolled strip is pickled with mixed acid, which uses nitric acid and hydrofluoric acid mixed pickling, using two-stage mixed acid, the nitric acid concentration is 60-100g / l, the hydrofluoric acid concentration is 0-5g / l, the temperature is controlled at 40-50°C, and the iron ion concentration is controlled within 40g / l.

[0006] The shot blasting after the scale breaking includes: using 6 shot blasting machines, the rotation speed is 1750rpm, and the current is controlled at 90A.

[0007] The method for online annealing of the SUS410L cold-rolled strip also includes: the annealing temperature is 835-850° C., and the annealing time is 100-120 seconds.

[0008] The beneficial effects of the present invention are: The invention mainly ensures that the temperature fluctuation range of the SUS410L annealing plate is controlled between ±8°C, the elongation at room temperature is 22-30%, the yield strength is 310-320Mpa, the tensile strength is 460-490Mpa, the performance is excellent and meets the needs.

[0009] The hot line online annealing production of SUS410L has reduced the delivery cycle by 3 days compared with the previous bell-type furnace annealing, and increased the production efficiency by 25% compared with other previous hot line production. DETAILED DESCRIPTION

[0010] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0011] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0012] The method for annealing and pickling SUS410L cold-rolled strip steel of the present invention comprises: performing online annealing on SUS410L cold-rolled strip steel, adding 5 zones compared with the 7 zones of the previous 1# hot line, with the furnace temperature being 825°C and 850°C-865°C, setting the furnace temperature of the first 3 zones to be rapidly raised to the annealing temperature, and keeping the furnace temperature of the last 9 zones unchanged, thereby increasing the annealing time; Scaling of SUS410L cold-rolled strip steel is performed. The scale breaking is controlled according to the tension mode. The tension is set to 340KN. Shot blasting is performed after scale breaking. The SUS410L cold-rolled strip was pickled with sulfuric acid, the sulfuric acid concentration was 280 g / l, the temperature was 80 °C, and the iron ion concentration was controlled within 45 g / l; The SUS410L cold-rolled strip is pickled with mixed acid, which uses nitric acid and hydrofluoric acid mixed pickling, using two-stage mixed acid, the nitric acid concentration is 60g / l, 80g / l or 100g / l, the hydrofluoric acid concentration is 0g / l, 3g / l or 5g / l, the temperature is controlled at 40°C, 45°C or 50°C, and the iron ion concentration is controlled within 40g / l.

[0013] The shot blasting after the scale breaking includes: using 6 shot blasting machines, the rotation speed is 1750rpm, and the current is controlled at 90A.

[0014] The method for online annealing of the SUS410L cold-rolled strip also includes: the annealing temperature is 835-850° C., and the annealing time is 100-120 seconds.

[0015] In the description of this specification, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0016] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. The method for annealing and pickling of SUS410L cold-rolled strip steel is characterized in that: include: For online annealing of SUS410L cold-rolled strip, 5 zones were added compared to the previous 7 zones of 1# hot line, and the furnace temperature was 825-865℃. The furnace temperature of the first 3 zones was set to be quickly raised to the annealing temperature, and the furnace temperature of the last 9 zones was kept unchanged to increase the annealing time; Scaling of SUS410L cold-rolled strip steel is performed. The scale breaking is controlled according to the tension mode. The tension is set to 340KN. Shot blasting is performed after scale breaking. The SUS410L cold-rolled strip was pickled with sulfuric acid, the sulfuric acid concentration was 280 g / l, the temperature was 80 °C, and the iron ion concentration was controlled within 45 g / l; The SUS410L cold-rolled strip is pickled with mixed acid, which uses nitric acid and hydrofluoric acid mixed pickling, using two-stage mixed acid, the nitric acid concentration is 60-100g / l, the hydrofluoric acid concentration is 0-5g / l, the temperature is controlled at 40-50°C, and the iron ion concentration is controlled within 40g / l.

2. The method for annealing and pickling SUS410L cold-rolled strip according to claim 1, characterized in that: The shot blasting after the scale breaking includes: using 6 shot blasting machines, the rotation speed is 1750rpm, and the current is controlled at 90A.

3. The method for annealing and pickling SUS410L cold-rolled strip according to claim 1, characterized in that: The method for online annealing of the SUS410L cold-rolled strip also includes: the annealing temperature is 835-850° C., and the annealing time is 100-120 seconds.