A cooling roll for producing an extremely thin strip of non-oriented silicon steel by plane flow casting and a method of manufacturing

Abstract

A cooling roller for producing non-oriented silicon steel ultra-thin strip by plane flow casting, which is composed of a cooling copper roller, characterized in that a nickel plating layer is provided on the surface of the cooling copper roller, and the thickness of the nickel plating layer is controlled to be 30-60 microns; the preparation method comprises the following steps: oil removal; pickling; alkali washing; chemical nickel plating; rinsing; drying; standby. The application can ensure that the B 50 ≥1.63T, P 1T / 400Hz ≤10.21W / kg, thickness is 0.02-0.16 mm, the nickel plating layer is formed by chemical nickel plating on the surface of the cooling copper roller, the adhesion of the cooling copper roller can be increased by 10% compared with that of the cooling copper roller, the production cost is relatively reduced by 25% compared with the current one, the surface of the cooling copper roller is not easy to be oxidized, and the qualified rate of the prepared non-oriented silicon steel ultra-thin strip is increased from the current 76% to not less than 85%.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of metal material preparation, and particularly relates to a cooling roller for producing an oriented silicon steel ultra-thin strip by plane flow casting and a preparation method. BACKGROUND

[0002] With the development of the power electronics industry towards high frequency, miniaturization and high power density, there are higher and higher requirements for the miniaturization and loss of magnetic devices, and the demand for oriented silicon steel ultra-thin strips with a thickness of less than 0.10 mm will greatly increase.

[0003] At present, the preparation of silicon steel ultra-thin strips mainly relies on multi-pass rolling method, but the traditional rolling technology has problems such as long process, high energy consumption and high cost. In recent years, some documents report the use of plane flow casting technology to prepare oriented silicon steel ultra-thin strips. This technology directly prepares silicon steel ultra-thin strips by cooling copper roller spinning. Compared with the traditional method, the process flow is relatively simple and the production efficiency is relatively high. However, due to the high melting point, poor flowability and high surface tension of the silicon steel melt, the adhesion and wettability of the cooling copper roller are poor, which makes the qualified rate of the oriented silicon steel ultra-thin strips produced by the technology not more than 70%, and the surface quality of the oriented silicon steel ultra-thin strips is poor and the magnetic properties are poor.

[0004] In order to solve the above problems, improving the wettability between the silicon steel melt and the cooling copper roller has become a research object. Some documents report that by adding surface active elements during silicon steel smelting to reduce the surface tension and viscosity of the melt, the wettability and spreading performance of the silicon steel melt and the cooling copper roller during plane flow casting are improved, the thin strip formability and surface quality are improved. For example, the search results are as follows:

[0005] The document with the Chinese patent publication number CN104561838A discloses a trace amount of tellurium modified silicon steel ultra-thin strip and a preparation method thereof. The silicon content of the oriented silicon steel thin strip is 2.8-3.3wt%, the tin content is 0.03-0.06wt%, and the tellurium content is 0.003-0.004wt%. The semi-process oriented silicon steel ultra-thin strip is formed by rapidly solidifying the high-temperature melt by spinning method, and then the trace amount of tellurium modified silicon steel ultra-thin strip is obtained by high-temperature annealing.

[0006] The document with the Chinese patent publication number CN117026081A discloses an oriented silicon steel ultra-thin strip containing element bismuth and a preparation method thereof. The silicon content of the oriented silicon steel ultra-thin strip is 2-4wt%, and the bismuth content is 0.005-0.05wt%. The oriented silicon steel ultra-thin strip is prepared by plane flow casting, and then the ultra-thin strip product is obtained by flattening and annealing.

[0007] The above two patent documents are to reduce the surface tension and viscosity of the melt by adding surface active elements such as tellurium or bismuth, and to improve the wetting and spreading performance of the silicon steel melt on the cooling copper roller. However, tellurium is easy to oxidize in the silicon steel smelting process, and bismuth is easy to volatilize in the smelting process, and both are expensive, which will lead to difficult smelting of the ultra-thin strip of non-oriented silicon steel and high production cost. Although the qualified rate of the produced non-oriented silicon steel ultra-thin strip is more than 70%, but also only not more than 76%, the surface quality and wetting and spreading of the non-oriented silicon steel ultra-thin strip are still poor. SUMMARY

[0008] The present application is to overcome the poor sticking problem between the silicon steel melt and the cooling copper roller in the prior art, and to provide a cooling roller for planar flow casting production of non-oriented silicon steel ultra-thin strip, which can ensure B 50 ≥1.63T, P 1T / 400Hz ≤10.21W / kg, thickness in the range of 0.04-0.12mm, by plating nickel on the cooling copper roller, the sticking of the cooling copper roller can be improved by 10%, and the production cost is relatively reduced by 25% compared with the current, the qualified rate of the prepared non-oriented silicon steel ultra-thin strip is increased from the current 76% to not less than 85%.

[0009] The measures to achieve the above purpose are:

[0010] A cooling roller for planar flow casting production of non-oriented silicon steel ultra-thin strip, which is composed of a cooling copper roller, wherein a nickel plating layer is provided on the surface of the cooling copper roller, and the thickness of the nickel plating layer is controlled to be 30-60μm.

[0011] It is suitable for preparing a non-oriented silicon steel ultra-thin strip containing silicon in a weight percentage of 2-4.5%, the rest being iron and a small amount of other unavoidable impurities, and the prepared non-oriented silicon steel ultra-thin strip is in the range of 0.04-0.12mm.

[0012] A method for preparing a cooling roller for planar flow casting production of non-oriented silicon steel ultra-thin strip, comprising the following steps:

[0013] 1) oil removal, the cooling copper roller is placed in an oil removal liquid with a temperature of 50-65℃ for cleaning for 15-25min, and stirring is continued until the oil removal is completed;

[0014] 2) pickling, the oil-removed cooling copper roller is placed in a pickling solution with a nitric acid concentration of 10-15wt% for pickling for 10-15min;

[0015] 3) alkaline cleaning, the pickled cooling copper roller is placed in an alkaline cleaning solution containing sodium hydroxide 4.5-6.0wt%, sodium dodecylbenzenesulfonate 0.1-0.4wt% at a temperature of 50-65℃ for alkaline cleaning for 15-20min, and then repeatedly washed with distilled water until clean.

[0016] 4) performing chemical nickel plating, immersing the cooled copper roller rinsed by distilled water into a chemical nickel plating solution for 30-40 min, so as to make it fully react and deposit a 30-60 μm-thick nickel plating layer on the surface of the cooled copper roller, and stirring is performed during the period;

[0017] The temperature of the chemical nickel plating solution is controlled at 70-85 ℃, the pH of the chemical nickel plating solution is controlled at 4.5-5.0, and the nickel content in the formed nickel plating layer is not less than 85 wt%;

[0018] 5) performing rinsing, using distilled water to rinse the residual liquid on the surface of the nickel plating layer clean;

[0019] 6) performing drying, controlling the drying temperature at 100-110 ℃, and controlling the drying time at 2-3 h;

[0020] 7) standby.

[0021] The composition and weight percentage content of the oil removal liquid are as follows: sodium carbonate: 2.0-3.0%, sodium phosphate: 2.0-3.5%, sodium dodecyl benzene sulfonate: 0.1-0.3%, and the rest is water.

[0022] The composition and weight percentage content of the chemical nickel plating solution are as follows: nickel chloride: 9.5-12%, nickel sulfate: 3.0-5.5%, citric acid: 3.5-5.0%, ethylenediamine sulfate: 1.5-3.0%, boric acid: 2.0-3.0%, sodium thiosulfate: 1.5-2.0%, sodium hypophosphite: 2.5-4.0%, and the rest is water; the pH of the chemical nickel plating solution is 4.5-5.0, and the pH value is adjusted by boric acid.

[0023] The role and mechanism of the main process in the application

[0024] The reason why the nickel plating is performed on the surface of the cooled copper roller in the application is that, compared with adding expensive surface active elements in raw materials, the chemical nickel plating treatment on the copper roller has low cost, simple process, and does not need to consider the problems such as oxidation or volatilization of surface active elements in the smelting process; at the same time, the sticking property between the prepared non-oriented ultra-thin strip and the cooled roller is obviously improved, the plasticity and toughness of the thin strip are good, the yield is high, and the quality and magnetic performance are obviously improved. This is because the chemical nickel plating on the cooled copper roller can improve the wettability and spreading performance of the silicon steel melt, thereby improving the yield, surface quality and magnetic performance of the prepared non-oriented silicon steel ultra-thin strip by plane flow casting. The chemical nickel plating on the copper roller has low cost, simple process and is relatively mature, and the influence of the thin plating layer on the heat transfer of the cooled copper roller is small. And in the non-oriented silicon steel, expensive tellurium and bismuth and other surface active elements do not need to be added, the smelting is easier, and the material preparation is lower.

[0025] The present application performs the steps of oil removal, pickling, alkaline cleaning, electroless nickel plating, rinsing and drying, mainly to ensure that the plating solution formed in the process of electroless nickel plating has good stability and suitable reactivity. The synergistic effect of various steps and components helps to form a uniform and dense coating and provides the required physicochemical properties.

[0026] The present application controls the concentration of sodium phosphate to be 2.0-3.5%, because the addition of phosphorus ions can improve the stability of the solution during nickel plating. This helps to prevent the precipitation of metal impurities, maintain the cleanliness of the plating solution, and avoid negative effects on the adhesion of the coating. Phosphorus ions provide active sites for the adsorption of hydrogen and nickel ions, acting as a catalyst to accelerate the nickel plating reaction and deposit more nickel on the surface of the copper roller to form a uniform coating. The dense structure of phosphorus increases the wear resistance, corrosion resistance and hardness of the coating.

[0027] The present application controls the concentration of nickel chloride to be 9.5-12% and the concentration of nickel sulfate to be 3.0-5.5%, because this concentration range has a moderate deposition rate, good hardness and toughness. Higher concentrations of nickel chloride or nickel sulfate may increase the deposition rate and consume more nickel chloride in local areas of the workpiece, leading to uneven deposition of the nickel layer. In addition, the accelerated consumption of nickel ions causes poor stability of the plating solution, easy spontaneous decomposition, deposition of other impurities on the surface of the copper roller, increased brittleness of the nickel layer, and a rough surface of the coating. Lower concentrations mean slower deposition rate, reduced production efficiency and thinner coating, which cannot achieve the desired effect.

[0028] The present application controls the concentration of sodium hypophosphite to be 2-4.5%, because this concentration range has a moderate reaction speed. Higher concentrations may cause the reaction to speed up, the plating solution to undergo spontaneous decomposition, and the process control to be more difficult. Lower concentrations cannot control the pH value of the electroless plating solution and regulate the stability of the plating solution, leading to decreased stability of the plating solution, uneven quality of the coating, and difficult control of the reaction rate. By adjusting the reaction process, the density, gloss and uniformity of the coating can be improved, ensuring good mechanical properties and appearance characteristics.

[0029] The present application controls the concentration of citric acid to be 3.5-5.0% and the concentration of boric acid to be 2.0-3.0%, because this concentration range has a greater impact on the quality of the plating solution and the density, gloss and uniformity of the coating. Higher concentrations of citric acid or boric acid may cause the plating solution to be too acidic or have too strong buffering capacity, leading to decreased coating quality and unstable reaction rate. Lower concentrations may cause insufficient buffering capacity of the plating solution, making it difficult to maintain stable reaction conditions and affecting the quality and uniformity of the coating.

[0030] The present application controls the concentration of ethylenediamine sulfate at 1.5-3.0%, because too high concentration leads to the decrease of plating solution stability, affects the uniformity and quality of the plated layer, even produces organic pollutants, increases the brittleness of the plated layer, reduces the corrosion resistance of the plated layer, and further causes defects of the plated layer; too low concentration leads to the lack of necessary organic additives in the plating solution, so that the plated layer surface is not smooth enough and the brightness is reduced. The addition of ethylenediamine sulfate can make the plated layer surface have better gloss, and at the same time, the pH value of the plating solution can be adjusted to provide a stable plating solution environment.

[0031] Compared with the prior art, the present application guarantees B 50 ≥1.63T, P 1T / 400Hz ≤10.21W / kg, the thickness is in the range of 0.04-0.12mm, the nickel plating layer is formed by electroless nickel plating on a cooling copper roller, the adhesion to the roller of the cooling copper roller can be improved by 10%, the production cost is relatively reduced by 25% compared with the current, and the qualified rate of the prepared extremely thin strip of non-oriented silicon steel is increased from the current 76% to not less than 85%. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 It is a structural schematic diagram of the cooling copper roller of the present application;

[0033] Figure 2 It is an extremely thin strip of non-oriented silicon steel prepared by the embodiment of the present application;

[0034] In the figure: 1-cooling copper roller, 2-nickel plating layer. DETAILED DESCRIPTION

[0035] The present application will be described in detail below in combination with the drawings:

[0036] Table 1 is a list of main process parameters of each embodiment of the present application;

[0037] Table 2 is a list of composition and content values of each solution in the process of each embodiment of the present application;

[0038] Table 3 is a list of effect detection situations of each embodiment of the present application.

[0039] A cooling copper roller for preparing an extremely thin strip of non-oriented silicon steel by plane flow casting, which is composed of a cooling copper roller 1, the surface of which is treated by electroless nickel plating to form a nickel plating layer 2 with a thickness of 30-60μm.

[0040] Each embodiment is prepared according to the following method, and the steps are as follows:

[0041] 1) oil removal, the cooling copper roller 1 is put into an oil removal liquid with a temperature of 50-65℃ for cleaning for 15-25min, and stirring is continuously carried out until the oil removal is completed;

[0042] 2) acid washing, the cooled copper roller 1 after oil removal is placed in the acid washing liquid with the concentration of nitric acid of 10-15wt% for acid washing for 10-15min;

[0043] 3) alkali washing, the cooled copper roller 1 after acid washing is placed in the alkali washing liquid with the temperature of 50-65 DEG C and containing 4.5-6.0wt% of sodium hydroxide and 0.1-0.4wt% of sodium dodecyl benzene sulfonate for alkali washing for 15-20min, and then repeatedly washed with distilled water until clean;

[0044] 4) chemical nickel plating, the cooled copper roller 1 after washing with distilled water is immersed in the chemical nickel plating solution for 30-40min, so that it is fully reacted and a nickel plating layer 2 with the thickness of 30-60um is deposited on the surface of the cooled copper roller 1, and stirring is carried out during the period; the temperature of the chemical nickel plating solution is controlled at 70-85 DEG C, the pH of the chemical nickel plating solution is controlled at 4.5-5.0; the content of nickel in the formed nickel plating layer is not less than 85wt%;

[0045] 5) rinsing, residual liquid on the surface of the nickel plating layer 2 is rinsed clean with distilled water;

[0046] 6) drying, the drying temperature is controlled at 100-110 DEG C, and the drying time is 2-3h;

[0047] 7) standby.

[0048] The present application is described in the preparation of the oriented silicon steel very thin strip:

[0049] 1, the following examples: all for the preparation of silicon weight percentage in 2-4.5%, the rest is iron and a small amount of other inevitable impurities, the preparation thickness in the range of 0.04-0.12mm of non-oriented silicon steel very thin strip.

[0050] 2, the present application needs to control the equipment related parameters before spinning, wherein, the roll nozzle distance is controlled at 0.1-0.3mm, the nozzle injection pressure is controlled at 30-70kPa, and the cooling roller speed is controlled at 10-25m / s. The reason is that the non-oriented silicon steel very thin strip prepared in the above process parameter range has the best formability, fewer defects and good surface quality.

[0051] 3, the present application controls the superheat of the master alloy melt at 30-100 DEG C, because the viscosity of the melt is lower, the flowability is better, and the oxidation degree of the melt is smaller in the temperature range, avoiding the problems of large viscosity and poor flowability of the melt caused by low superheat and easy oxidation of the melt caused by high superheat.

[0052] 4、The present application needs to level and anneal the prepared cast strip, wherein the leveling reduction is controlled at 2-5%, the reason is that small reduction not only can improve the surface quality of the thin strip, but also can improve the magnetic properties to a certain extent, but too large reduction will destroy the already formed favorable texture and lead to the decrease of magnetic properties. The annealing temperature is controlled at 800-1000℃, and the temperature is kept for 40-100min, which is because it can control the best grain size and texture, so that the magnetic properties are further improved.

[0053] Table 1 list of main process parameters of each embodiment of the present application

[0054]

[0055] Table 2 list of composition and content value of each solution in the process of each embodiment of the present application (wt%)

[0056]

[0057] Table 2 continued

[0058]

[0059]

[0060] Table 3 list of effect detection results of each embodiment of the present application

[0061]

[0062] From Table 3, the quality of the plating layer is crucial to the successful preparation of non-oriented silicon steel thin strip. If the chemical nickel plating process parameters are not within the appropriate range, the formed plating layer is often uneven, leading to uneven surface of the thin strip, poor plating layer adhesion and easy to fall off, and then affecting the thin strip yield. In addition, higher porosity will also reduce the surface quality of the thin strip. Therefore, it is necessary to operate within the above chemical nickel plating process parameter range to ensure the uniformity and quality of the plating layer.

[0063] The specific embodiments are only the best examples, and are not a restrictive implementation of the technical solutions of the present application.

Claims

1. A cooling roller for planar flow casting to produce ultra-thin non-oriented silicon steel strips, comprising a cooling copper roller, characterized in that: A nickel plating layer is provided on the surface of the cooling copper roller, and the thickness of the nickel plating layer is controlled to be 30~60μm; Preparation method: 1) To remove oil, immerse the cooling copper roller in an oil removal solution at a temperature of 50~65℃ for 15~25 minutes and continue stirring until the oil removal is complete; 2) Perform pickling: Place the degreased cooled copper roller in a pickling solution with a nitric acid concentration of 10~15wt% for pickling for 10~15 minutes; 3) Perform alkaline washing. Place the acid-washed cooled copper roller in an alkaline washing solution containing 4.5-6.0 wt% sodium hydroxide and 0.1-0.4 wt% sodium dodecylbenzenesulfonate at a temperature of 50-65℃ for 15-20 minutes, and then rinse repeatedly with distilled water until clean. 4) Perform electroless nickel plating. Immerse the cooled copper roller, after rinsing with distilled water, in the electroless nickel plating solution for 33-40 minutes to allow for full reaction and deposition of a 30-60 μm thick nickel plating layer on the surface of the cooled copper roller, while stirring during the process. The temperature of the electroless nickel plating solution is controlled at 70-85℃, and the pH of the electroless nickel plating solution is controlled at 4.5-5. The nickel content in the formed nickel plating layer is not less than 85 wt%. 5) Rinse thoroughly with distilled water to remove any residual liquid from the nickel plating layer. 6) Dry the product, controlling the drying temperature at 100~110℃ and the drying time at 2~3 hours; 7) Reserved.

2. The cooling roller for producing non-oriented silicon steel ultra-thin strips by planar flow casting as described in claim 1, characterized in that: It is suitable for preparing silicon steel strips with a weight percentage of 2-4.5%, the remainder being iron and a small amount of other unavoidable impurities, and the resulting non-oriented silicon steel strips are 0.04-0.12 mm thick.

3. A method for preparing a cooling roller for producing non-oriented silicon steel ultrathin strips by planar flow casting as described in claim 1, comprising the following steps: 1) To remove oil, immerse the cooling copper roller in an oil removal solution at a temperature of 50~65℃ for 15~25 minutes and continue stirring until the oil removal is complete; 2) Perform pickling: Place the degreased cooled copper roller in a pickling solution with a nitric acid concentration of 10~15wt% for pickling for 10~15 minutes; 3) Perform alkaline washing. Place the acid-washed cooled copper roller in an alkaline washing solution containing 4.5-6.0 wt% sodium hydroxide and 0.1-0.4 wt% sodium dodecylbenzenesulfonate at a temperature of 50-65℃ for 15-20 minutes, and then rinse repeatedly with distilled water until clean. 4) Perform electroless nickel plating. Immerse the cooled copper roller, after rinsing with distilled water, in the electroless nickel plating solution for 33-40 minutes to allow for full reaction and deposition of a 30-60 μm thick nickel plating layer on the surface of the cooled copper roller, while stirring during the process. The temperature of the electroless nickel plating solution is controlled at 70-85℃, and the pH of the electroless nickel plating solution is controlled at 4.5-5. The nickel content in the formed nickel plating layer is not less than 85 wt%. 5) Rinse thoroughly with distilled water to remove any residual liquid from the nickel plating layer. 6) Dry the product, controlling the drying temperature at 100~110℃ and the drying time at 2~3 hours; 7) Reserved.

4. The method for preparing a cooling roller for producing non-oriented silicon steel ultrathin strips by planar flow casting as described in claim 3, characterized in that: The composition and weight percentage of the degreasing solution are as follows: sodium carbonate: 2.0~3.0%, sodium phosphate: 2.0~3.5%, sodium dodecylbenzenesulfonate: 0.1~0.3%, and the remainder is water.

5. The method for preparing a cooling roller for producing non-oriented silicon steel ultrathin strips by planar flow casting as described in claim 3, characterized in that: The composition and weight percentage of the electroless nickel plating solution are as follows: nickel chloride: 9.5~12%, nickel sulfate: 3.0~5.5%, citric acid: 3.5~5.0%, ethylenediamine sulfate: 1.5~3.0%, boric acid: 2.0~3.0%, sodium thiosulfate: 1.5~2.0%, sodium hypophosphite: 2.5~4.0%, and the remainder is water; the pH of the electroless nickel plating solution is 4.5~5.0, and its pH value is adjusted by boric acid.

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