Production method of grinding-free high-chromium ultra-pure ferritic stainless steel cold-rolled sheet

Abstract

The invention discloses a grinding-free high-chromium ultra-pure ferritic stainless steel cold-rolled sheet production method which comprises the following steps: raw material annealing and pickling: after a shot blasting procedure and a sulfuric acid pickling procedure of the raw material annealing and pickling, respectively using a heavy brush to brush iron scales on the surface of the raw material, controlling the rotating speed of the heavy brush to be 500-750rpm, controlling the power to be 50-70KW, and controlling the reduction ratio to be greater than or equal to 20%; during cold rolling, the roughness and deformation of a roller are controlled, specifically, in the first pass of cold rolling, the roughness of the roller is 0.8-1.0 mu m, and the deformation is controlled to be 22-25%; from the second pass of cold rolling to the pass before a finished product, the roughness of a roller is 0.2-0.4 mu m, and the deformation is controlled to be 13-20%; and in the finished product pass of cold rolling, the roughness of the roller is 0.1-0.2 mu m, and the deformation is controlled to be 10-20%. According to the method, the surface quality of the high-chromium ultra-pure ferrite stainless steel cold-rolled sheet is ensured, the coping procedure can be omitted, a hot coil is free of coping, the production efficiency and the yield are improved, the manufacturing cost is reduced, and the economical efficiency and competitiveness of products are effectively improved.

Description

Technical Field

[0001] The invention belongs to the technical field of ferritic stainless steel production, and in particular relates to a method for producing a grinding-free high-chromium ultra-pure ferritic stainless steel cold-rolled plate. Background Art

[0002] The main production process of ferritic stainless steel cold-rolled sheet is: smelting → continuous casting → hot rolling → cold rolling. High chromium ultra-pure ferritic stainless steel with chromium content ≥ 20% is prone to surface stripes and scale defects due to roller sticking during hot rolling. In the subsequent cold rolling production, it is often necessary to grind the surface before rolling to improve the surface defects before rolling.

[0003] The grinding process can improve surface defects and remove residual oxide scale on the surface. However, compared with hot wire and cold wire, the grinding process is extremely inefficient. Adding the grinding process not only increases the process cost, but also prolongs the delivery time, reduces the yield rate, and affects the competitiveness of the product. Summary of the invention

[0004] In order to solve the technical problems existing in the above-mentioned prior art, the present invention provides a method for producing a grinding-free high-chromium ultra-pure ferritic stainless steel cold-rolled sheet, which is particularly suitable for the cold rolling production of high-chromium ultra-pure ferritic stainless steel products with a chromium content of 20 to 22%, comprising:

[0005] (1) Raw material annealing and pickling: After the shot blasting process of raw material annealing and pickling and after the sulfuric acid pickling process, the iron scale on the raw material surface is brushed with a heavy brush, wherein the bristles of the heavy brush are made of hard bristles doped with silicon carbide, the heavy brush speed is controlled to be 500-750rpm, the power is controlled to be 50-70KW, and the reduction ratio is controlled to be ≥20%;

[0006] (2) Control of roll roughness and deformation during cold rolling: In the first pass of cold rolling, the roll roughness is 0.8-1.0 μm, and the deformation is controlled to be 22-25%; in the second pass to the pass before the finished product, the roll roughness is 0.2-0.4 μm, and the deformation is controlled to be 13-20%; in the finished product pass of cold rolling, the roll roughness is 0.1-0.2 μm, and the deformation is controlled to be 10-20%.

[0007] The method for producing high-chromium ultra-pure ferritic stainless steel cold-rolled sheet without grinding of the present invention has the following advantages and beneficial effects: the present invention significantly improves the cleaning performance by using the heavy brush during the annealing and pickling of the raw materials, and can further clean the surface scales, and the heavy brushed surface has a metallic luster, eliminating the white surface caused by passivation; by controlling the roughness and deformation of the roller during cold rolling, the surface quality of the high-chromium ultra-pure ferritic stainless steel cold-rolled sheet is further ensured, the product has no surface defects, the surface brightness is effectively improved, the surface roughness is significantly reduced, and the surface qualified rate reaches more than 96%. Moreover, the method for producing high-chromium ultra-pure ferritic stainless steel cold-rolled sheet without grinding of the present invention can omit the grinding process, and the hot coil does not need to be ground, which improves the production efficiency and yield rate, reduces the manufacturing cost, and effectively improves the economic and competitive nature of the product. DETAILED DESCRIPTION

[0008] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific 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 making creative work are within the scope of protection of the present invention.

[0009] After a large number of industrial production certifications, the grinding-free high-chromium ultra-pure ferritic stainless steel cold-rolled plate production method proposed in the present invention is suitable for the cold rolling production of high-chromium ultra-pure ferritic stainless steel products with a chromium content of 20-22%. Its main technical measures include: (1) optimizing the raw material annealing and pickling process before cold rolling, and improving the conventional raw material annealing and pickling process including annealing-scaling-shot blasting-sulfuric acid pickling-mixed acid pickling to a new raw material annealing and pickling process including annealing-scaling-shot blasting-rebrushing-sulfuric acid pickling-rebrushing-mixed acid pickling; (2) controlling the roughness and deformation of the rollers during cold rolling.

[0010] Specifically, the method for producing a grinding-free high-chromium ultrapure ferrite stainless steel cold-rolled sheet of the present invention comprises:

[0011] (1) Raw material annealing and pickling: After the shot blasting process of raw material annealing and pickling and after the sulfuric acid pickling process, the iron scale on the raw material surface is brushed with a heavy brush. The bristles of the heavy brush are made of hard bristles doped with silicon carbide, for example, imported bristles from Japan CONTANY Company can be used. The heavy brush speed is controlled to 500-750rpm, the power is controlled to 50-70KW, and the reduction ratio is controlled to ≥20%;

[0012] (2) Control of roll roughness and deformation during cold rolling: In the first pass of cold rolling, the roll roughness is 0.8-1.0 μm, and the deformation is controlled to 22-25% to increase metal flow; in the second pass to the pass before the finished product, the roll roughness is 0.2-0.4 μm, and the deformation is controlled to 13-20%; in the finished product pass of cold rolling, the roll roughness is 0.1-0.2 μm, and the deformation is controlled to 10-20%.

[0013] The following is a detailed description of the method for producing a grinding-free high-chromium ultra-pure ferritic stainless steel cold-rolled sheet of the present invention in conjunction with specific embodiments. The implementation methods in the following embodiments without specifying specific conditions are carried out according to conventional methods and conditions, and the present invention does not make specific limitations on this.

[0014] The embodiment of the present invention is applied to the batch production of TTS443M high chromium ultra-pure ferrite stainless steel cold-rolled sheet for elevator panels, with a production volume of about 3,000 tons / month and a product qualification rate of more than 96%, wherein the raw material annealing and pickling are carried out on the 3# hot line, the cold rolling is carried out on the narrow width 2-8# rolling mill, and the finished product pickling is carried out on the 3# cold line, specifically including:

[0015] (1) Raw material annealing and pickling: the process is implemented according to annealing-scaling-shot blasting-re-brushing-sulfuric acid pickling-re-brushing-mixed acid pickling, wherein the scale breaking is controlled according to the tension mode and the tension is set to 340KN; 6 shot blasting machines are used, the speed of the shot blasting machines is 1750rpm, and the current is controlled at 90A; the sulfuric acid concentration for sulfuric acid pickling is 280g / l, the temperature is 80°C, and the iron ion concentration is controlled within 45g / l; after shot blasting and sulfuric acid pickling, the iron scale on the raw material surface is brushed with re-brushing, the re-brushing speed is 600rpm, the power is 55KW, and the reduction ratio is 21%;

[0016] (2) Control of roll roughness and deformation during cold rolling: In the first pass of cold rolling, a roll with a roughness of 0.94 μm and a deformation of 23% is selected; in the second pass to the pass before the finished product, a roll with a roughness of 0.28 μm and a deformation of 15-18% is selected; in the finished product pass of cold rolling, a roll with a roughness of 0.14 μm and a deformation of 15% is selected.

[0017] In summary, the method for producing high-chromium ultra-pure ferritic stainless steel cold-rolled sheet without grinding of the present invention can significantly improve the cleaning performance by using the heavy brushing during the annealing and pickling of the raw materials, and can further clean the surface scales. The heavy brushed surface has a metallic luster, eliminating the white surface caused by passivation. By controlling the roughness and deformation of the rollers during cold rolling, the surface quality of the high-chromium ultra-pure ferritic stainless steel cold-rolled sheet is further ensured, the product has no surface defects, the surface brightness is effectively improved, the surface roughness is significantly reduced, and the surface qualified rate reaches more than 96%. More importantly, the method for producing high-chromium ultra-pure ferritic stainless steel cold-rolled sheet without grinding of the present invention can omit the grinding process, and the hot coil is free of grinding, which improves the production efficiency and yield rate, reduces the manufacturing cost, and effectively improves the economic and competitive nature of the product.

[0018] It should be noted that, in this article, the term "comprise" or any other variation thereof is intended to cover non-exclusive inclusion, so that an article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such article or device.

[0019] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for producing grinding-free high-chromium ultra-pure ferrite stainless steel cold-rolled sheet, characterized in that: include: (1) Raw material annealing and pickling: After the shot blasting process of raw material annealing and pickling and after the sulfuric acid pickling process, the iron scale on the raw material surface is brushed with a heavy brush, wherein the bristles of the heavy brush are made of hard bristles doped with silicon carbide, the heavy brush speed is controlled to be 500-750rpm, the power is controlled to be 50-70KW, and the reduction ratio is controlled to be ≥20%; (2) Control of roll roughness and deformation during cold rolling: In the first pass of cold rolling, the roll roughness is 0.8-1.0 μm, and the deformation is controlled to be 22-25%; in the second pass to the pass before the finished product, the roll roughness is 0.2-0.4 μm, and the deformation is controlled to be 13-20%; in the finished product pass of cold rolling, the roll roughness is 0.1-0.2 μm, and the deformation is controlled to be 10-20%.

2. The method for producing grinding-free high-chromium ultra-pure ferrite stainless steel cold-rolled sheet according to claim 1, characterized in that: It is used for cold rolling production of high chromium ultra-pure ferritic stainless steel products with chromium content of 20-22%.