Pickling method for 2205 duplex stainless steel coils
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A duplex stainless steel and pickling technology, applied in the field of metallurgy, can solve problems affecting the pickling effect of strip steel, achieve the effects of shortening pickling time, reasonable step design, and ensuring utilization efficiency
Inactive Publication Date: 2019-03-12
ZHENSHI GROUP EASTERN SPECIAL STEEL
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Problems solved by technology
The most important pickling of typical duplex stainless steel lies in the pre-pickling and other supporting pickling sections, because the pre-pickling and other supporting pickling sections determine the pickling surface quality and pickling time, only for pre-pickling and other supporting pickling sections The pickling speed of the steel coil can be controlled only if the solution ratio in the pickling section is reasonable, and the steel coil that meets the customer's requirements can be washed out with the best pickling speed and reasonable acid concentration and temperature. There are also shortcomings and deficiencies in existing pickling methods. For example, the Chinese invention patent whose authorization notification number is CN103820798B: a continuous pickling production method for hot-rolled duplex stainless steel strips. In this application, the pickling method steps are followed by phosphorus removal, sulfuric acid Electrolytic pickling pre-pickling, abrasive scrubbing, sulfuric acid pickling, mixed acid pickling, and re-washing mixed acid pickling. There is no rinsing step between the steps of this pickling method, so the actual concentration of the acid solution in each step is not the set acid. The concentration of the liquid will ultimately affect the pickling effect of the strip
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Embodiment 1
[0018] In this embodiment, the hot-rolled and annealed 022Cr23Ni5Mo3N duplex stainless steel coil with a thickness of 8.0mm is pickled, and the specific steps are:
[0019] Step 1: Use a shot blasting machine to mechanically descale the annealed steel coil, with a total throwing rate of 2200kg / min;
[0020] Step 2: The steel coil after descaling enters the pickling section for pre-pickling. The medium used for pre-pickling is sulfuric acid with a concentration of 280g / l. The pickling temperature is 75°C. The metal ion content is 25g / l. 10m / min;
[0021] Step 3: After the pre-pickling, enter the first-level brushing. The medium used in the first-level brushing is water. The equipment for the first-level brushing uses multiple sets of brush rollers. The front and back of the brush rollers are equipped with water spray pipes. For the reactants remaining on the surface of the strip, the feeding speed is 10m / min;
[0022] Step 4: After first-level scrubbing, enter double-mixed ac...
Embodiment 2
[0029] In this embodiment, the hot-rolled and annealed 022Cr23Ni5Mo3N duplex stainless steel coil with a thickness of 10.0mm is pickled, and the specific steps are:
[0030] Step 1: Use a shot blasting machine to mechanically descale the annealed steel coil, with a total throwing rate of 2200kg / min;
[0031] Step 2: The steel coil after descaling enters the pickling section for pre-pickling. The medium used for pre-pickling is sulfuric acid with a concentration of 290g / l. The pickling temperature is 73°C. The metal ion content is 23g / l. 10m / min;
[0032] Step 3: After the pre-pickling, enter the first-level scrubbing. The medium used in the first-level scrubbing is water. The equipment for the first-level scrubbing uses multiple sets of brush rollers. The front and rear of the brush rollers are equipped with water spray pipes. For the reactants remaining on the surface of the strip, the feeding speed is 10m / min;
[0033] Step 4: After first-level brushing, enter double-mixed...
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Abstract
The invention relates to a pickling method for 2205 duplex stainless steel coils. The pickling method comprises the following steps that mechanical descaling is carried out on annealed steel coils; pre-pickling is carried out on descaled steel coil in the pickling stage; primary scrubbing is carried out after the pre-pickling; double-mixed acid pickling is carried out after the primary scrubbing;three-stage scrubbing is carried out after the double-mixed acid pickling; and a cleaning stage is entered after the three-stage scrubbing, and a drying stage is entered after cleaning. The pickling process is reasonable, complete and simple in step design; a high-concentration sulfuric acid solution and a low-concentration mixed acid solution are adopted, the metal ions is guaranteed, and the utilization efficiency of the acid liquid is guaranteed; and the solutions of the pre-pickling and other matched acid washing stages are reasonable proportioned, the pickling speed, the acid liquid concentration and the temperature are reasonable, so that the pickling time is shortened, the iron oxide scale on the surface of the duplex stainless steel coil is removed, and therefore the use requirements of NO.1 plate can be met.
Description
technical field [0001] The invention relates to the field of metallurgy, in particular to a pickling method for 2205 duplex stainless steel coils. Background technique [0002] Stainless steel pickling is to use acid to carry out surface acid chemical treatment on stainless steel with scale on the surface, remove the oxide layer and chromium-poor layer formed on the surface of stainless steel after high temperature annealing, and passivate simultaneously to form no oxide layer residue, and finally reach the market The surface state of the NO.1 board required. [0003] Due to the particularity of the composition and structure of duplex stainless steel, its structure is a stainless steel in which austenite phase and ferrite phase coexist. Compared with other stainless steels, due to the different content of Cr, Ni, N, and Mo, the double phase The oxide layer on the surface of phase stainless steel is extremely dense, and the structure type of the formed oxide is very complex....
Claims
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Application Information
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