A low-consumption, corrosion-resistant, high-surface-quality production method that replaces cold products with heat

Abstract

The invention relates to a low-consumption method for producing products with corrosion resistance and high surface quality by replacing cold-rolling by hot-rolling. The method comprises the following steps: uncoiling by an uncoiler; crushing oxides on the surface of strip steel by a temper mill; further crushing and peeling the oxides on the surface of the strip steel by a multi-roll straightening machine; removing part of oxides on the surface of the strip steel by using a washing device; pickling and rinsing the flatten, straightened and washed strip steel; introducing the pickled strip steel into a mechanical grinding device to repair surface defects; removing residues on the surface of the strip steel in a mechanical manner; coiling by a coiler. By adopting the technical scheme, the method has the advantages that: the quick permeation of the acid liquid is facilitated and the pickling efficiency is improved; part of oxide is removed, the pickling reaction amount is reduced and the acid consumption is reduced; the yield strength additional value of the strip steel processed by phosphorus breakage is low, the performance is almost not influenced; Luders strips which are normally formed on the surfaces of common hot rolling products are avoided; through mechanical surface grinding, the surface quality of the strip steel is improved; due to the mechanical manner of cleaning the residues on the surface, the corrosion resistance of products is improved.

Description

technical field [0001] The invention belongs to the technical field of deep processing of ordinary hot-rolled flat materials, and in particular relates to a production method of low-consumption, corrosion-resistant, high-surface-quality products by substituting heat for cold products. Background technique [0002] Such as figure 1 As shown, the traditional pickling unit consists of uncoiler 1, inlet looper 2, tension leveler 3, pickling 4, rinse 30, exit looper 5, skin pass machine 22 and coiler 6, and the tension leveler 3. Mechanical phosphorus breaking is carried out. Restricted by the phosphorus breaking effect, the pickling time of the unit is long and the efficiency is low. After pickling 4, the surface of the product is a chemical reaction surface, with poor coloring and various surface quality defects. It is difficult to achieve cold rolling after skin pass. The general quality requirements of the board. [0003] Such as figure 2 As shown, the main reason for the...

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Problems solved by technology

[0004] In order to maintain the performance of the strip steel 7, it is necessary to set the elongation of the tension leveler 3 above the yield limit of the strip steel, so that the strip steel 7 produces plastic deformation. In this working condition, after the strip steel 7 leaves the tension leveler 3 It can partially maintain the gap of surface oxide 8 and improve pickling efficiency, but the performance loss of the product is serious. For conventional hot-rolled sheets with interstitial atoms such as carbon and nitrogen content ≥ 30ppm, unevenness will occur on the strip surface after tension leveling Surface yielding, commonly known as Lüders band 10; for high-strength steel and IF steel, although Lüders band 10 will not be produced on the surface of the strip, because its yield strength increases unidirectionally with the increase of elongation, therefore, Increased elongation will undoubtedly deteriorate product performance

[0005] like Figure 4 and Figure 5 As shown, after pickling 4, the main reason for the poor surface quality of the product is that the final surface of the product is a direct chemical reaction surface. 8 are Fe 2 o 3 31. Fe 3 o 4 32. FeO 33, the above three kinds of oxides 8 have different degrees of difficulty in reacting with acid, the FeO 33 located in the lowest layer is the most likely to react with pickling 4, in this state, the acid solution and oxide 8 and the The reaction time of the steel 7 body is basically the same, and the surface quality of the strip steel 7 after pickling 4 is uniform; however, in actual production, some Fe 3 o 4 32 will be deposited on the surface of strip steel 7, due to Fe 3 o 4 32 and FeO 33 have different reaction times with the acid solution, resulting in uneven reaction between the acid solution and the strip steel 7, resulting in the surface quality of the strip steel 7 after pickling 4 cannot meet the use requirements of most products

[0006] After strip steel is through pickling 4, there will be acid solution residual on the surface, and, for the strip steel 7 that surface quality is poorer, the residual amount of surface acid solution is bigger, and these residual chloride ions can seriously corrode the strip steel 7 surface, make the strip steel The surface of steel strips is yellow or yellow-green spots, and these strips are not as bright as normal strips after rolling, and the finished products are prone to re-corrosion

[0007] In order to reduce acid residue, the strip steel 7 is traditionally cleaned by multi-stage rinsing 30 , and the temperature of rinsing 30 is continuously raised during the rinsing 30 , increasing the kinetic energy of molecules in the rinsing 30 tank, and accelerating the diffusion of acid solution. Generally, the last stage rinsing 30 The temperature of the rinsing 30 is about 85°C, which increases the energy consumption of the production process. Even so, from the actual production situation, the acid concentration in the final rinsing 30 tank is still 100mg / l-150mg / l

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