A method for producing products with low acid consumption and high surface quality by substituting heat for cold products

Abstract

The invention relates to a method for producing products by replacing cold by using heat with low acid consumption and high surface quality. The method comprises the following steps: uncoiling by an uncoiler; crushing and peeling 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 the shed and loosened oxides on the surface of the strip steel by using a washing roller in a washing device; pickling and poaching the flatten, straightened and washed strip steel; introducing the pickled strip steel into a mechanical grinding device for carrying out surface grinding; homogenizing the surface roughness of the strip steel; coiling the processed strip steel into a finished product. By adopting the technical scheme, the method has the advantages that 1, the quick permeation of the acid liquid is facilitated and the pickling efficiency is improved; 2, part of oxide peel is removed, the pickling reaction amount is reduced and the acid consumption is reduced; 3, the yield strength additional value of the processed strip steel is low; 4, Luders strips, which are normally formed on the surfaces of common hot rolling products are avoided; 5, through mechanical surface treatment after pickling, the surface quality of the strip steel is improved.

Description

technical field [0001] The invention belongs to the field of deep processing of ordinary hot-rolled flat materials, and in particular relates to a production method for products with low acid consumption and high surface quality by substituting heat for cold products. Background technique [0002] In the existing technology, such as figure 1 As shown, the traditional pickling unit consists of an uncoiler 1, an inlet looper 2, a tension leveler 3, pickling 4, an outlet looper 5, a skin pass machine 22 and a coiler 6. The hot-rolled strip 7 passes through the surface The treatment process removes the oxide 8 on the surface of the board, and then it can replace some cold-rolled products after being treated by a skin pass machine. It is used in construction, automobiles, home appliances and other fields. This product has a great cost competitive advantage. A tension leveler 3 is installed at the entrance of the unit for mechanical descaling. The strip steel after descaling ente...

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Problems solved by technology

[0004] In order to maintain the performance of the strip steel 7, the elongation of the tension leveler 3 needs to be set below the yield limit of the strip steel. The oxide cracks 9 on the surface of the steel 7 are closed, so in the process of pickling 4, it is difficult for the acid solution to penetrate from the closed oxide cracks 9 to FeO33 and react with it, and the pickling efficiency is very low

[0005] In order to improve the pickling efficiency, 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 can be plastically deformed. In this working condition, the strip steel 7 can be Partially maintain the gap of surface oxide 8 to improve pickling efficiency, but this method will cause serious loss of product performance

[0006] like image 3 As shown, for conventional hot-rolled sheets with interstitial atoms such as carbon and nitrogen content ≥ 30ppm, after tension leveling machine 3 performs tension leveling, uneven surface yielding will occur on the surface of strip steel 7, commonly known as Lüders strip 10; for carbon Although the high-strength steel and IF steel in the steel will not produce Lüders band 10 on the surface of the strip, because the yield strength increases unidirectionally with the increase of the elongation, increasing the elongation will undoubtedly deteriorate the product. performance

[0007] like Figure 4 and Figure 5 Shown, after carrying out pickling 4, the main reason that product surface quality is not high is that the final surface of product is the direct chemical reaction surface, under ideal state, the oxide 8 on strip steel 7 surface, the oxidation of from surface layer to inner layer 8 are Fe 2 o 3 31. Fe 3 o 4 32. FeO33, the above-mentioned three kinds of oxides 8 have different degrees of difficulty in reacting with acid, and the FeO33 located in the lowest layer is the most likely to react with pickling 4. In this state, the acid solution, oxide 8 and strip steel 7 The reaction time of the 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 strip surface, due to Fe 3 o 4 32 and FeO33 have different reaction times with the acid solution, resulting in an uneven reaction between the acid solution and the strip steel 7, resulting in the surface of the strip steel 7 after pickling 4 being treated by the unit outlet tempering machine, unable to completely eliminate color difference and Other surface defects cannot meet the use requirements of most products. Therefore, the traditional production process of substituting heat for cooling restricts the market application of substituting heat for cooling products

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