CN106435607B - Environment-friendly continuous annealing and pickling production method for stainless steel hot-rolled coil and pickling solution - Google Patents
Environment-friendly continuous annealing and pickling production method for stainless steel hot-rolled coil and pickling solution Download PDFInfo
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- CN106435607B CN106435607B CN201610505060.8A CN201610505060A CN106435607B CN 106435607 B CN106435607 B CN 106435607B CN 201610505060 A CN201610505060 A CN 201610505060A CN 106435607 B CN106435607 B CN 106435607B
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
- C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
- C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
- C23G1/08—Iron or steel
- C23G1/086—Iron or steel solutions containing HF
Abstract
Environment-friendly continuous annealing and pickling production method for stainless steel hot-rolled coilThe production method comprises annealing, straightening, shot blasting, pre-pickling and pickling, wherein the pickling comprises at least one pickling step, and the mixed acid used for pickling mainly comprises the following components: 10-80 g/L sulfuric acid, 0-40 g/L hydrofluoric acid, 0-30 g/L hydrogen peroxide and 30-50 g/L Fe3+，0＜Fe2+Less than or equal to 30g/L, 1-5 g/L of acid washing additive and the balance of water; the pickling also comprises at least one spray pickling, the spray pickling is carried out after the pickling, and the spray pickling mainly comprises the following spray acid liquid: 10-80 g/L sulfuric acid, 0-40 g/L hydrofluoric acid, 10-50 g/L hydrogen peroxide and 30-50 g/L Fe3+，0＜Fe2+Less than or equal to 30g/L, 1-5 g/L of acid washing additive and the balance of water. The invention adopts the combination of acid leaching and pickling and spraying and pickling, combines the improved formula of acid leaching and acid spraying, effectively solves the technical problems of yellow spots on the surface of the strip steel, corrosion resistance reduction of the strip steel and the like, and meets the requirements of a new environmental protection method.
Description
Technical Field
The invention belongs to the technical field of stainless steel annealing and pickling, and particularly relates to an environment-friendly continuous annealing and pickling production method of a stainless steel hot-rolled coil and a pickling solution.
Background
The stainless steel hot rolled coil has a high-temperature oxidation phenomenon in the production process, and an oxidation layer formed on the surface of the stainless steel hot rolled coil influences the quality and the processing performance of the processed surface, so that the stainless steel hot rolled coil can be completely removed for subsequent production and use. In the large production process, the acid cleaning and the annealing of the stainless steel hot rolled coil are combined together to form an annealing and acid cleaning combined unit, and the acid cleaning process flow mainly comprises the working procedures of mechanical descaling, pre-acid cleaning and mixed acid cleaning.
The mixed acid pickling mainly utilizes the pickling solution and FeO and Fe in the oxide skin3O4、Fe2O3、Cr2O3NiO and SiO2And the substances are subjected to forced chemical reaction to promote the dissolution of the oxide skin. In the process, three actions of dissolving the oxide scale by acid, mechanically stripping the oxide scale by hydrogen and reducing partial oxide scale by hydrogen are carried out simultaneously or alternately. At present, it is mature andthe widely used mixed acid pickling method for stainless steel is HNO3+ HF acid leaching process. The method has the advantages of high pickling speed, clean peeling and good pickling surface quality. However, the process also presents the polluting gas NOxAnd environmental protection factors such as nitrate discharge and sludge landfill treatment. In 2015, China begins to implement new environmental protection laws and emission standards, and the total nitrogen in the steel industry is required to be not more than 15mg/l, which is for HNO3The + HF pickling process presents a serious challenge.
In recent years, a part of factories begin to use mixed acid liquid without nitric acid, such as sulfuric acid, hydrofluoric acid and hydrogen peroxide, to carry out pickling on stainless steel cold-rolled annealed coils, and a good pickling effect is achieved. However, the pickling method has strong corrosion capability and weak passivation capability, and the problems of yellow spots, reduced corrosion resistance and the like easily occur after acid pickling of the stainless steel hot rolled coil when the pickling method is applied to pickling of the stainless steel hot rolled coil.
Disclosure of Invention
The invention aims to provide an environment-friendly stainless steel hot-rolled coil continuous annealing and pickling production method and pickling solution, which solve the problems that yellow spots are easy to appear on the surface of a stainless steel hot-rolled coil after pickling in the prior art, the corrosion resistance of steel is reduced and the like, and the pickling solution does not contain nitric acid, meets the requirements of a new environment-friendly method, and simultaneously realizes efficient and rapid production of stainless steel.
In order to achieve the purpose, the technical scheme of the invention is as follows:
an environment-friendly continuous annealing and pickling production method of a stainless steel hot-rolled coil comprises the following steps: annealing, straightening, shot blasting, pre-pickling and pickling, wherein the pickling comprises at least one pickling step,
the main composition and content of the mixed acid liquid used for acid pickling are as follows:
furthermore, the acid cleaning also comprises at least one spray acid cleaning, which is carried out after the acid pickling, wherein,
the spraying acid liquor used for spraying and pickling mainly comprises the following components in percentage by weight:
and in the spraying and pickling process, spraying and pickling are carried out on the upper surface and the lower surface of the stainless steel hot-rolled coil in the acid leaching and pickling process.
The pickling additive in the mixed acid liquid and the sprayed acid liquid is a pickling inhibitor and/or a pickling promoter.
Preferably, the pickling inhibitor is urotropin (hexamethylenetetramine), a pickling corrosion inhibitor HIBIRON and other inhibitors suitable for stainless steel pickling.
Preferably, the pickling accelerator is SUNSPEED and other accelerators suitable for pickling stainless steel.
The invention relates to an environment-friendly pickling solution for stainless steel hot-rolled coils, which is a mixed acid solution for pickling stainless steel hot-rolled coils, and the mixed acid solution mainly comprises the following components in percentage by weight:
the invention relates to an environment-friendly stainless steel hot-rolled coil pickling solution, which is a spraying acid solution for spraying pickling of stainless steel hot-rolled coils, and the spraying acid solution mainly comprises the following substances in parts by weight:
wherein the pickling additive is a pickling inhibitor and/or a pickling accelerator.
Preferably, the acid pickling inhibitor is urotropin (hexamethylenetetramine) and/or acid pickling corrosion inhibitor HIBIRON, and other inhibitors suitable for stainless steel acid pickling.
Preferably, the pickling accelerator is SUNSPEED and other accelerators suitable for pickling stainless steel.
In the mixed acid solution, sulfuric acid mainly dissolves oxide skin on the inner layer of stainless steel and a substrate, so that the oxide skin mechanically peels off the substrate; hydrofluoric acid mainly removes the outer oxide skin of the stainless steel; the hydrogen peroxide mainly removes the chromium-poor layer of the stainless steel and also plays the role of an oxidant to react Fe2+Oxidation to Fe3+；Fe3+Mainly plays a role in passivation and improves the corrosion resistance of the surface of the stainless steel; the pickling promoter can promote the pickling efficiency; the pickling inhibitor can effectively inhibit the corrosion of acid liquor to the strip steel matrix and improve the surface quality of the strip steel. For the rolled austenitic and duplex stainless steel with better corrosion resistance, the surface quality of the steel plate is good after acid pickling by adopting the mixed acid liquid.
Compared with the traditional mixed acid of nitric acid and hydrofluoric acid, the acid pickling method has the advantages that the acid pickling corrosion products of sulfuric acid and hydrofluoric acid are more, and Fe3+The passivation capability is relatively weak, and for nickel-saving austenitic stainless steel, low-chromium ferrite and martensitic stainless steel with poor corrosion resistance, yellow spots and the corrosion resistance of strip steel are easy to appear on the surface of a stainless steel hot-rolled coil subjected to acid washing by only adopting an acid pickling method. Although the problem can be improved by increasing the content of hydrogen peroxide in the mixed acid solution, the problems of increased pickling cost and unobvious improvement effect still exist. Therefore, the spraying device is additionally arranged at the outlet of the acid leaching tank for spraying and pickling, so that the problems can be well solved.
According to the invention, the content of hydrogen peroxide in the sprayed acid liquid is increased to 10-50 g/L, and through high-pressure spraying and pickling, the effect of removing corrosion products on the surface of the stainless steel hot-rolled coil can be improved, and the surface passivation capability of the stainless steel hot-rolled coil can be obviously improved. In addition, the spraying and pickling are added, so that the pickling speed can be obviously improved, and the production cost is saved.
The invention has the beneficial effects that:
according to the invention, through the combination of acid pickling and spray pickling, and by combining the improvement of the formula of acid pickling and acid liquor spraying, the technical problems of yellow spots on the surface of the stainless steel hot-rolled coil, the reduction of the corrosion resistance of strip steel and the like are effectively solved, the efficient continuous annealing and pickling of martensite, ferrite, austenite and dual-phase stainless steel hot-rolled coils are realized, and the surface quality of the pickled steel plate is good.
The continuous annealing and pickling production method does not adopt nitric acid, does not discharge nitride, and meets the discharge requirement of a new environmental protection method.
Drawings
FIG. 1 is a schematic view of a continuous annealing and pickling line for a hot-rolled stainless steel coil according to an embodiment of the present invention.
FIG. 2 is a front view of a combined pickling section of pickling and spraying according to an embodiment of the present invention.
Fig. 3 is a top view of fig. 2.
FIG. 4 is a photograph showing the surface macro-morphology of SUS304 stainless steel after acid pickling according to the method of example 1.
FIG. 5 is a photograph showing the macro-morphology of the surface of SUS439 stainless steel after acid pickling by the method of example 2.
FIG. 6 is a photograph showing the macro-morphology of the surface of SUS409L stainless steel after acid pickling in the same manner as in example 3.
Detailed Description
The following examples are given to illustrate specific embodiments of the present invention, but the present invention is not limited to the following examples.
As shown in fig. 1-3, the continuous annealing and pickling production line for the environment-friendly stainless steel hot rolled coil comprises an annealing furnace 1, a pulling, straightening and descaling machine 2, a shot blasting machine 3, a pre-pickling section 4, a pickling section I5 and a pickling section II 6.
In this example, two acid washes were performed, including acid wash stage I5 and acid wash stage II 6. The pickling I section 5 comprises an acid tank 51 and a spraying device 52, the pickling II section 6 comprises an acid tank 61 and a spraying device 62, and the lengths of the acid tank 51 and the acid tank 61 are 22 meters.
In the acid washing production, the strip steel 7 enters the acid tank 51 and the acid tank 61 in an approximately upward opening parabola due to the self weight, wherein the strip steel 7 is sent into the acid tank 61 through the pinch roll 8 after exiting the acid tank 51. The length of the steel strip 7 submerged in each acid tank 51, 61 is about 20 meters, and the length of the steel strip 7 at the two ends of each acid tank 51, 61 is 1 meter higher than that of the mixed acid liquid 53, 63. A set of spray devices 52 and 62 are respectively arranged on the upper surface and the lower surface of the strip steel 7 500mm in front of the outlets of the acid tank 51 and the acid tank 61, each set of spray devices is provided with 6 spray nozzles, the total number of the spray devices is 4, and the total number of the spray nozzles is 24. The spraying devices 52 and 62 are connected with a spraying acid liquid tank through a spraying pipeline 9.
Example 1
This example is an acid wash of hot rolled coils of duplex and austenitic stainless steels.
The steel coil is welded on a production line, and the concentration of each substance of the mixed acid liquid used in the pickling section I5 and the pickling section II 6 is as follows:
in this embodiment, the pickling additive is a pickling accelerator SUNSPEED produced by North China fir chemical Co.
The concentration of hydrogen peroxide in the composition of the sprayed acid solution used in the spraying devices 52 and 62 is 10g/L, and the rest is the same as above.
The temperature of the mixed acid solution and the temperature of the sprayed acid solution are both 50 ℃, the acid washing speed is 55m/min, and the macroscopic morphology of the surface of the SUS304 stainless steel after acid washing is shown in FIG. 4.
As can be seen from FIG. 4, the surface of the strip steel is white and smooth, and is cleaned by acid pickling, and the surface quality is good.
Example 2
This example is an acid pickling of a hot-rolled 400 high and high chromium ferritic stainless steel coil.
The steel coil is welded on a production line, and the concentrations of all substances in the mixed acid liquor of the I section 5 and the II section 6 are mixed acid washing:
in the embodiment, the pickling additive is 1.5g/L pickling accelerator SUNSPEED and 1.5g/L pickling corrosion inhibitor HIBIRON, which are produced by North China fir chemical Co., Ltd.
The concentration of hydrogen peroxide in the spraying acid liquid composition is 30g/L, and the rest is the same as above.
The temperature of the mixed acid solution and the temperature of the sprayed acid solution are both 45 ℃, the acid washing speed is 50m/min, and the macroscopic morphology of the surface of the SUS439 stainless steel after acid washing is shown in FIG. 5.
As can be seen from FIG. 5, the surface of the strip steel is white and smooth, and is cleaned by acid pickling, and the surface quality is good.
Example 3
In this example, a hot-rolled 400 low-chromium ferrite and martensitic stainless steel coil was pickled.
The steel coil is welded on a production line, and the concentrations of all substances in the mixed acid liquor of the mixed acid washing I section 5 and the mixed acid washing II section 6 are as follows:
the concentration of hydrogen peroxide in the spraying acid liquid composition is 50g/L, and the rest is the same as above.
The temperature of the mixed acid solution and the temperature of the sprayed acid solution are both 40 ℃, the acid washing speed is 50m/min, and the macro-morphology and the micro-morphology of the surface of the SUS409L stainless steel after acid washing are shown in FIG. 6.
As can be seen from FIG. 6, the surface of the strip steel is white and smooth, and is cleaned by acid pickling, and the surface quality is good.
Claims (9)
1. An environment-friendly stainless steel hot-rolled coil continuous annealing and pickling production method comprises annealing, straightening and withdrawal treatment, shot blasting treatment, pre-pickling and pickling, and is characterized in that the pickling comprises at least one acid pickling step,
the main composition and content of the mixed acid solution used for acid pickling are as follows:
the acid cleaning also comprises at least one spray acid cleaning which is carried out after the acid cleaning, wherein,
the spraying acid liquor used for spraying and pickling mainly comprises the following components in percentage by weight:
2. the continuous annealing and pickling process for a hot-rolled stainless steel coil according to claim 1, wherein the spray pickling process comprises spray pickling the upper and lower surfaces of the hot-rolled stainless steel coil.
3. The continuous annealing pickling production method of a stainless steel hot-rolled coil according to claim 1, wherein the pickling additive is a pickling inhibitor and/or a pickling accelerator.
4. The continuous annealing and pickling production method of the stainless steel hot-rolled coil according to claim 3, wherein the pickling inhibitor is hexamethylenetetramine and/or a pickling corrosion inhibitor HIBIRON.
5. The continuous annealing and pickling production method of the stainless steel hot-rolled coil according to claim 3, wherein the pickling accelerant is pickling accelerant SUNSPEED.
6. The environment-friendly pickling solution for the stainless steel hot-rolled coil is characterized by comprising a mixed acid solution for pickling, wherein the mixed acid solution mainly comprises the following components in percentage by weight:
the pickling solution also comprises a spraying acid solution for spraying pickling, and the spraying acid solution mainly comprises the following components in percentage by weight:
7. the pickling solution for hot-rolled stainless steel coils of claim 6, wherein the pickling additive is a pickling inhibitor and/or a pickling accelerator.
8. The pickling solution for hot-rolled stainless steel coils according to claim 7, wherein the pickling inhibitor is hexamethylenetetramine and/or a pickling corrosion inhibitor HIBIRON.
9. The pickling solution for hot-rolled stainless steel coils according to claim 7, wherein the pickling accelerator is SUNSPEED.
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| CN110699695A (en) * | 2019-10-22 | 2020-01-17 | 曲靖中铭科技有限公司 | Heterochromatic treatment method for stainless steel MIM product |
| CN110747407B (en) * | 2019-11-19 | 2021-04-27 | 浦项(张家港)不锈钢股份有限公司 | Austenitic stainless steel for preparing fork spoon and manufacturing method and application thereof |
| CN111575452A (en) * | 2020-05-21 | 2020-08-25 | 山东泰山钢铁集团有限公司 | Method for reducing hot-rolled pickling surface roughness of 10Cr17 stainless steel |
| CN111876582A (en) * | 2020-06-28 | 2020-11-03 | 中北大学 | Continuous annealing and pickling method for iron-aluminum-chromium alloy hot coil |
| CN112323082B (en) * | 2020-09-28 | 2022-09-09 | 甘肃酒钢集团宏兴钢铁股份有限公司 | Annealing and pickling method for duplex stainless steel strip and steel strip produced by using annealing and pickling method |
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