Method for high-precision and high-efficiency electrolytic extraction of non-metallic inclusions in steel

Abstract

The invention relates to the technical field of metal physical research methods, in particular to a method for high-precision and high-efficiency electrolytic extraction of non-metallic inclusions in steel, which comprises the following steps: 1) preparing a steel sample; 2) magnetizing the steel sample; 3) electrolysis; and (4) inclusions are collected. The magnetized low-carbon steel sample to be electrolyzed is put into the heat treatment furnace, the magnetic performance of the steel sample can be improved through heat treatment, and internal stress generated in the magnetization process can be eliminated. The magnetized low-carbon steel sample to be electrolyzed serves as an anode, during electrolysis, under the action of a magnetic field, metal particles can be adsorbed to the anode, electrolysis continues until metal disappears completely, under the action of the magnetic field, the ion moving track is changed, the activity degree of charged ions between electrodes is improved, the uniformity of the electrolytic reaction is improved, and the electrolysis efficiency is improved. And meanwhile, the electrolysis efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of metal physical research methods, and particularly to a method for electrolytically extracting non-metallic inclusions in steel with high precision and high efficiency. Background Art

[0002] With the development of modern engineering technology, people's requirements for the purity of steel are constantly increasing. To a certain extent, the quality of steel depends on the quantity, morphology, and size distribution of inclusions in the steel. The inclusion content is an important indicator for evaluating the grade of steel. The reported methods for extracting non-metallic inclusions generally include acid dissolution method and electrolysis method. Among them, the electrolysis method includes aqueous solution electrolysis and non-aqueous solution electrolysis. Both methods separate the inclusions from the steel through electrolysis, and then filter, extract, and weigh them. Through particle size and chemical composition analysis, information on the content, type, and particle size of non-metallic inclusions in the steel can be obtained.

[0003] Chinese Patent with application number 200910084741.1 discloses a method for electrolytically extracting fine inclusions in steel using a neutral salt electrolyte solution. This method uses aqueous solution electrolysis. Specifically, sodium citrate, sodium chloride, ferrous sulfate, and ammonium chloride are mixed in a certain proportion as the neutral electrolytic solution. After electrolysis, the undissolved matter is continuously reacted with ammonium chloride solution in a water bath, and the precipitate is repeatedly dissolved until the precipitate mass no longer changes. The obtained substance is the required inclusion.

[0004] Chinese Patent with application number 201910494354.9 discloses a method for electrolytically extracting inclusions in steel using a non-aqueous solution. This method uses non-aqueous solution electrolysis. By preparing a non-aqueous solution electrolyte, under certain electrolysis parameters, the inclusions and the steel matrix are electrolyzed into the non-aqueous solution, and then the inclusions are extracted and separated by centrifugation. The composition of the non-aqueous solution electrolyte (mass percentage) is 10% acetylacetone, 0.7% tetramethylammonium chloride, 1 - 5% ammonium thiocyanate, and the rest is anhydrous methanol. This invention enables the electrolysis process not to damage the inclusions in the steel, achieving the purpose of non-destructively extracting the inclusions in the steel.

[0005] Although the above electrolysis methods can achieve the purpose of extracting non-metallic inclusions in steel, there are still certain defects. Since metal particles will fall off from the anode metal during the electrolysis process. The fallen metal particles will contain non-metallic inclusions, resulting in the inability to extract these inclusions, and thus leading to deviations in the total amount of non-metallic inclusions counted. Summary of the Invention

[0006] To overcome the defects of the prior art, the technical problem solved by the present invention is to provide a method for electrolytically extracting non-metallic inclusions in steel with high precision and high efficiency, which can solve the problem that it is difficult to extract non-metallic inclusions contained in the fallen metal particles.

[0007] To achieve the above object, the present invention is implemented by the following technical solutions:

[0008] A method for electrolytically extracting non-metallic inclusions in steel with high precision and high efficiency, comprising the following steps:

[0009] 1) Prepare a steel sample

[0010] Prepare a low-carbon steel sample, which is in a cuboid structure;

[0011] Grind and polish the low-carbon steel sample, clean it with an organic solvent or an alkaline solution after grinding and polishing, then rinse it with clean water, and perform a drying treatment to finally obtain a low-carbon steel sample to be electrolyzed;

[0012] 2) Magnetize the steel sample

[0013] Put the low-carbon steel sample to be electrolyzed obtained in step 1) into a magnetizer for magnetization, and the magnetization time is 30 - 180 s; the maximum surface magnetic field intensity of the magnetized steel sample is not less than 0.08 T;

[0014] Put the magnetized low-carbon steel sample to be electrolyzed into a heat treatment furnace for annealing, and cool it to room temperature after annealing; package the cooled low-carbon steel sample to be electrolyzed for later use;

[0015] 3) Electrolyze

[0016] Take out the low-carbon steel sample to be electrolyzed from the package as the anode, and put it into an electrolytic cell for electrolysis. The composition of the electrolyte is 1 - 5% isophthalic acid, 3 - 9% triethanolamine, 3 - 9% glycerol, 1 - 4% acetylacetone by weight percentage, and the balance is anhydrous methanol; the length and width of the cathode plate are not less than those of the anode; the maximum surfaces of the anode and the cathode plate are kept parallel, the long sides of the anode and the cathode plate are perpendicular to the bottom surface of the electrolytic cell, and after fixing, connect to a power supply. Adjust the current density to 0.1 - 0.5 A / cm 2 ; control the temperature of the electrolyte to be 20 - 30 °C, and continuously introduce argon into the electrolytic cell during electrolysis, and the flow rate is 0.1 - 0.3 L / min;

[0017] 4) Collect inclusions

[0018] After electrolysis, wash the anode mud containing inclusions with anhydrous ethanol, suck out the magnetic substance particles with a magnet, and then centrifuge and clarify repeatedly through a centrifuge. Finally, obtain non-metallic inclusions; weigh the non-metallic inclusions after sufficient drying to obtain the total amount of non-metallic inclusions.

[0019] The carbon content of the low-carbon steel is less than 0.25%.

[0020] The drying treatment method is natural air drying or drying in a low-temperature drying oven.

[0021] The surface roughness of the low-carbon steel sample to be electrolyzed obtained in step 1) is not greater than 0.05 mm.

[0022] The organic solvent is acetone.

[0023] The electrolytic cathode material is graphite, metallic titanium or stainless steel.

[0024] The heat treatment furnace is heated to the annealing temperature at a rate of 10 - 20 °C / min, the annealing temperature is 300 - 500 °C, the annealing holding time is 30 - 90 min; the cooling rate is 5 - 10 °C / min.

[0025] The length and width of the cuboid structure are both 150 - 400 mm, and the thickness is 5 - 20 mm.

[0026] The thickness of the cathode plate is 1 - 20 mm.

[0027] The amount of the electrolyte is 1 / 2 - 4 / 5 of the volume of the electrolytic cell.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] In the present invention, the magnetized low-carbon steel sample to be electrolyzed is put into a heat treatment furnace. Through heat treatment, the magnetic properties of the steel sample can be improved, the internal stress generated during the magnetization process can be eliminated, and the stability of the steel sample can be enhanced.

[0030] In the present invention, the magnetized low-carbon steel sample to be electrolyzed is used as the anode. During electrolysis, under the action of the magnetic field, metal particles will adsorb on the anode. Continue electrolysis until the metal completely disappears. And under the action of the magnetic field, the running trajectory of ions is changed, the activity degree of charged ions between the electrodes is increased, the uniformity of the electrolysis reaction is improved, the generation of metal particles is reduced, and at the same time, the electrolysis efficiency is enhanced.

[0031] The electrolyte prepared in the present invention is a non-aqueous electrolyte. After electrolysis for a long time, the pH value of the electrolyte can still be maintained between 6.5 and 7.5. This non-aqueous neutral electrolyte can ensure that the electrolyte does not damage inclusions.

[0032] In the present invention, the length and width of the cathode plate are not less than those of the anode sample, which can ensure the improvement of the electrolysis efficiency. Detailed Embodiments

[0033] The following further describes the detailed embodiments of the present invention:

[0034] Example 1

[0035] The present invention provides a method for electrolytically extracting non-metallic inclusions in steel with high precision and high efficiency, including the following steps:

[0036] 1) Prepare a steel sample

[0037] Prepare a low-carbon steel sample as DH36, which has a cuboid structure with a length of 380 mm, a width of 180 mm, and a thickness of 10 mm. The carbon content of the low-carbon steel sample is 0.12% (mass percentage).

[0038] Grind and polish the low-carbon steel sample, clean it with acetone after grinding and polishing, then rinse it with clean water, and air-dry it naturally or dry it in a low-temperature drying oven. Finally, obtain the low-carbon steel sample to be electrolyzed. The surface roughness of the low-carbon steel sample to be electrolyzed is 0.04 mm.

[0039] 2) Magnetize the steel sample

[0040] Put the low-carbon steel sample to be electrolyzed obtained in step 1) into a magnetizer for magnetization. The magnetization time is 50 s; the maximum surface magnetic field strength of the magnetized steel sample is 0.1 T;

[0041] Put the magnetized low-carbon steel sample to be electrolyzed into a heat treatment furnace for annealing, and cool it to room temperature after annealing; pack the cooled low-carbon steel sample to be electrolyzed for later use. The heat treatment furnace heats up to the annealing temperature at a rate of 12 °C / min, the annealing temperature is 350 °C, and the annealing holding time is 35 min; the cooling rate is 6 °C / min. The low-carbon steel sample to be electrolyzed can be packed with plastic film. After packing, avoid vibration and avoid placing it in a strong magnetic field area.

[0042] 3) Electrolysis

[0043] Take out the low-carbon steel sample to be electrolyzed from the package as the anode and put it into the electrolytic cell for electrolysis. The electrolyte composition by weight percentage is 3% isophthalic acid, 6% triethanolamine, 6% glycerol, 1.5% acetylacetone, and the balance is anhydrous methanol. The amount of the electrolyte is 3 / 5 of the volume of the electrolytic cell.

[0044] The length of the graphite cathode plate is 400 mm, the width is 190 mm, and the thickness of the cathode plate is 10 mm. The maximum surfaces of the anode and the cathode plate are kept parallel, and the long sides of the anode and the cathode plate are perpendicular to the bottom surface of the electrolytic cell. After fixing, connect to the power supply. During electrolysis, adjust the current density to 0.15 A / cm 2 ; Control the temperature of the electrolyte to 25 °C, and continuously introduce argon into the electrolytic cell during electrolysis at a flow rate of 0.15 L / min.

[0045] 4) Collect inclusions

[0046] After electrolysis, the anode mud containing inclusions was washed with absolute ethanol, and the magnetic substance particles were sucked out with a magnet. Then, it was centrifuged and clarified repeatedly by a centrifuge, and finally non-metallic inclusions were obtained. After the non-metallic inclusions were fully dried, they were weighed, and the total amount of non-metallic inclusions was 342 mg. The total amount of the consumed anode during electrolysis was 4.15 kg. The ratio of the total amount of non-metallic inclusions to the total amount of the consumed anode during electrolysis can be used to obtain the percentage of the mass of inclusions in steel per unit mass, which is 82.4 mg / 1 kg.

[0047] Example 2

[0048] The present invention provides a method for electrolytically extracting non-metallic inclusions in steel with high precision and high efficiency, including the following steps:

[0049] 1) Prepare a steel sample

[0050] A low-carbon steel sample DH36 was prepared, which had a cuboid structure with a length of 300 mm, a width of 200 mm, and a thickness of 15 mm. The carbon content of the low-carbon steel sample was 0.12% (mass percentage).

[0051] The low-carbon steel sample was ground and polished, washed with acetone after grinding and polishing, then rinsed with clean water, and air-dried naturally or dried in a low-temperature drying oven. Finally, a low-carbon steel sample to be electrolyzed was obtained. The surface roughness of the low-carbon steel sample to be electrolyzed was 0.03 mm.

[0052] 2) Magnetize the steel sample

[0053] The low-carbon steel sample to be electrolyzed obtained in step 1) was placed in a magnetizer for magnetization, and the magnetization time was 100 s; the maximum surface magnetic field strength of the magnetized steel sample was 0.3 T;

[0054] The magnetized low-carbon steel sample to be electrolyzed was placed in a heat treatment furnace for annealing, and then cooled to room temperature after annealing; the cooled low-carbon steel sample to be electrolyzed was packaged for use. Among them, the heat treatment furnace was heated to the annealing temperature at a speed of 18 °C / min, the annealing temperature was 400 °C, and the annealing holding time was 50 min; the cooling speed was 8 °C / min. The low-carbon steel sample to be electrolyzed can be packaged in a paper box. After packaging, it should be avoided from being vibrated and placed in a strong magnetic field area.

[0055] 3) Electrolysis

[0056] The low-carbon steel sample to be electrolyzed was taken out from the package as the anode and placed in an electrolytic cell for electrolysis. The composition of the electrolyte by weight percentage was 2% isophthalic acid, 7% triethanolamine, 4% glycerol, 3% acetylacetone, and the balance was anhydrous methanol. The amount of the electrolyte was 4 / 5 of the volume of the electrolytic cell.

[0057] The length of the titanium cathode plate is 310 mm, the width is 220 mm, and the thickness of the cathode plate is 2 mm. The largest surfaces of the anode and the cathode plate are kept parallel. The long sides of the anode and the cathode plate are perpendicular to the bottom surface of the electrolytic cell. After fixation, it is connected to the power supply. During electrolysis, the current density is adjusted to 0.2 A / cm 2 ; The temperature of the electrolyte is controlled at 22 °C. During electrolysis, argon gas is continuously introduced into the electrolytic cell at a flow rate of 0.2 L / min.

[0058] 4) Collect inclusions

[0059] After electrolysis, the anode mud containing inclusions is washed with absolute ethanol, and the magnetic substance particles are sucked out with a magnet. Then, it is centrifuged and clarified repeatedly by a centrifuge. Finally, non-metallic inclusions are obtained; after the non-metallic inclusions are fully dried and weighed, the total amount of non-metallic inclusions is 501 mg. The total amount of the consumed anode during electrolysis is 6.21 kg. The ratio of the total amount of non-metallic inclusions to the total amount of the consumed anode during electrolysis can be used to obtain the percentage of the mass of inclusions in steel per unit mass, which is 80.7 mg / 1 kg.

[0060] Comparative example

[0061] The experimental conditions of this comparative example are the same as those of Example 1, but the steel sample is not magnetized. Finally, the total amount of non-metallic inclusions obtained is 218 mg. The total amount of the consumed anode during electrolysis is 4.21 kg. The ratio of the total amount of non-metallic inclusions to the total amount of the consumed anode during electrolysis can be used to obtain the percentage of the mass of inclusions in steel per unit mass, which is 51.8 mg / 1 kg. It can be seen that the total amount of inclusions obtained by applying the method of this invention patent is significantly higher than that of the electrolysis method of the comparative example, indicating that the accuracy of extracting inclusions by this invention is relatively high.

[0062] However, this comparative example is only for illustrating the benefits brought by magnetizing the anode, and does not affect the novelty and creativity of other technical features of this invention, such as the shape and treatment method of the steel sample, the electrolyte ratio, the electrolysis parameters, etc.

[0063] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention. In addition, it should be noted that, among the various specific technical features described in the above specific embodiments, they can be combined in any suitable manner without conflict. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods. In addition, any combination can be made between various different embodiments of the present invention, as long as it does not violate the idea of the present invention, it should also be regarded as the content disclosed by the present invention.

Claims

1. A method for high-precision and high-efficiency electrolytic extraction of non-metallic inclusions in steel, characterized in that: The steps include: 1) Prepare steel sample A low-carbon steel sample is prepared, which is a rectangular parallelepiped structure; the low-carbon steel sample is ground and polished, and then cleaned with an organic solvent or an alkaline solution, and then rinsed with clean water, and dried to finally obtain the low-carbon steel sample to be electrolyzed; 2) Magnetized steel sample The low-carbon steel sample to be electrolyzed obtained in step 1) is placed in a magnetizer for magnetization, and the magnetization time is 30 to 180 seconds; the maximum surface magnetic field intensity of the magnetized steel sample is not less than 0.08T; The magnetized low-carbon steel sample to be electrolyzed is placed in a heat treatment furnace for annealing, and then cooled to room temperature after annealing; the cooled low-carbon steel sample to be electrolyzed is packaged for standby use; 3) Electrolysis Take out the low-carbon steel sample to be electrolyzed from the package as the anode, and put it into the electrolytic cell for electrolysis. The electrolyte composition is 1-5% isophthalic acid, 3-9% triethanolammonium, 3-9% propylene glycol, 1-4% acetylacetone, and the balance is anhydrous methanol. The length and width of the cathode plate are not less than the length and width of the anode. The largest surfaces of the anode and cathode plates are kept parallel, and the long sides of the anode and cathode plates are perpendicular to the bottom of the electrolytic cell. After fixing, connect the power supply, and adjust the current density to 0.1-0.5A / cm during electrolysis. 2 ; The temperature of the electrolyte is controlled at 20-30°C, and argon is continuously introduced into the electrolytic cell during electrolysis, with a flow rate of 0.1-0.3 L / min; 4) Collect inclusions After the electrolysis is completed, the anode mud containing inclusions is cleaned with anhydrous ethanol, the magnetic material particles are sucked out with a magnet, and then repeatedly centrifuged and clarified by a centrifuge to finally obtain non-metallic inclusions; the non-metallic inclusions are fully dried and weighed to obtain the total amount of non-metallic inclusions.

2. A method for high-precision and high-efficiency electrolytic extraction of non-metallic inclusions in steel according to claim 1, characterized in that: The carbon content of the low carbon steel is less than 0.25%.

3. The method for high-precision and high-efficiency electrolytic extraction of non-metallic inclusions in steel according to claim 1, characterized in that: The drying method in step 1) is to dry naturally or put it in a low-temperature drying box for drying.

4. The method for high-precision and high-efficiency electrolytic extraction of non-metallic inclusions in steel according to claim 1, characterized in that: The surface roughness of the low-carbon steel sample to be electrolyzed obtained in step 1) is not greater than 0.05 mm.

5. The method for high-precision and high-efficiency electrolytic extraction of non-metallic inclusions in steel according to claim 1, characterized in that: The organic solvent is acetone.

6. The method for high-precision and high-efficiency electrolytic extraction of non-metallic inclusions in steel according to claim 1, characterized in that: The electrolytic cathode material is graphite, metal titanium or stainless steel.

7. The method for high-precision and high-efficiency electrolytic extraction of non-metallic inclusions in steel according to claim 1, characterized in that: The heat treatment furnace is heated to an annealing temperature at a speed of 10 to 20°C / min, the annealing temperature is 300 to 500°C, the annealing holding time is 30 to 90 minutes, and the cooling speed is 5 to 10°C / min.

8. The method for high-precision and high-efficiency electrolytic extraction of non-metallic inclusions in steel according to claim 1, characterized in that: The length and width of the rectangular parallelepiped structure are both 150-400 mm, and the thickness is 5-20 mm.

9. The method for high-precision and high-efficiency electrolytic extraction of non-metallic inclusions in steel according to claim 1, characterized in that: The thickness of the cathode plate is 1 to 20 mm.

10. The method for high-precision and high-efficiency electrolytic extraction of non-metallic inclusions in steel according to claim 1, characterized in that: The amount of the electrolyte is 1 / 2 to 4 / 5 of the volume of the electrolytic cell.