High-toughness corrosion-resistant high-polishing nitrogen-containing stainless steel and preparation method thereof

Abstract

The invention provides high-toughness corrosion-resistant high-polishing nitrogen-containing stainless steel and a preparation method thereof. The high-toughness corrosion-resistant high-polishing nitrogen-containing stainless steel comprises the following components in percentage by weight: 0.2%-0.4% of carbon, 0.1%-0.4% of Si, 0.4%-0.6% of Mn, 12%-25% of chromium, 0.25%-4% of nickel, 0.1%-0.3% of nitrogen, 0.5%-3% of molybdenum, 0.5%-3% of vanadium and the balance of iron and residual elements. The preparation method comprises the following steps: preparing an electrode blank through electric furnace smelting, nitrogen blowing and alloy nitride adding, obtaining an electroslag ingot through electroslag remelting and adopting a ternary or multi-element slag system, and obtaining a finished product through forging and ultra-refining, thereby obtaining the material with good corrosion resistance, high hardness, polishing property and toughness.

Description

Technical Field

[0001] The invention relates to the technical field of nitrogen-containing stainless steel preparation, in particular to high-toughness, corrosion-resistant and high-polishing nitrogen-containing stainless steel and a preparation method thereof. Background Art

[0002] High toughness, corrosion resistant, high polish nitrogen-containing stainless steel is a stainless steel material with special properties. High toughness means that this stainless steel material has good tensile and impact resistance. It can withstand large forces without breaking or deforming easily, so it performs well in applications that require strength and durability. This stainless steel has excellent corrosion resistance and can resist erosion by oxidation, acidic and alkaline environments. This makes it widely used in marine environments, chemical industries and other fields. The material has good polishing properties and can obtain a very smooth surface through mechanical or chemical methods. The high polishing effect gives the stainless steel an aesthetic appearance. The addition of nitrogen can change the microstructure and properties of stainless steel. The introduction of nitrogen can improve the hardness, strength and wear resistance of the material while maintaining good corrosion resistance.

[0003] The current plastic mold steel market lacks materials that are corrosion-resistant, high hardness, polishable, and tough. Therefore, according to the applicant's invention, a high-toughness, corrosion-resistant, high-polish nitrogen-containing stainless steel and a preparation method thereof were invented to solve the problem that the mold cannot meet the use requirements. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the deficiencies in the prior art, the present invention provides a high-toughness, corrosion-resistant, high-polishing nitrogen-containing stainless steel and a preparation method thereof, which solves the problem that the mold cannot meet the use requirements.

[0006] (II) Technical solution

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions: A high-toughness, corrosion-resistant, high-polishing, nitrogen-containing stainless steel, comprising:

[0008] Chromium is 12%-25%, nickel is 0.25%-4%, nitrogen is 0.1%-0.3%, molybdenum is 0.5%-3%, and iron is 80%-85%.

[0009] Preferably, the nitrogen content is controlled at 1200ppm-1300ppm.

[0010] A method for preparing high-toughness, corrosion-resistant and highly polished nitrogen-containing stainless steel comprises the following steps:

[0011] S1. Select the above raw materials, and smelt and cast them according to the above components to obtain nitrogen-containing electrode blanks, and anneal the electrode blanks;

[0012] S2, remelting the electrode blank in an atmosphere-protected electroslag furnace to obtain a steel ingot, and annealing the steel ingot;

[0013] S3, forging the steel ingot to obtain a forging blank and annealing it;

[0014] S4, ultra-fine treatment of forging blank;

[0015] S5, spheroidizing annealing the steel billet after ultra-fine treatment, and obtaining steel after mechanical processing;

[0016] S6. Temper the steel and perform surface treatment such as polishing to obtain high hardness and high polishing surface;

[0017] S5. Conduct testing and quality control on the prepared materials, including chemical composition analysis, metallographic microscope observation, and mechanical property testing to ensure that the materials meet the specified requirements and standards.

[0018] Preferably, the smelting adopts an electroslag process, and the electroslag adopts a ternary slag system and a multi-component slag system.

[0019] Preferably, the electroslag ingot annealing process is divided into two stages, as follows: in the first stage, the furnace is loaded at 400°C, the temperature is evenly increased to 550°C within two hours, kept warm for 3 hours, the temperature is evenly increased to 780°C within 3 hours, kept warm for 18 hours, the temperature is evenly reduced to 550°C within 12 hours, the natural gas furnace is turned off for cooling, the temperature is reduced to 400°C, the fan is turned off for cooling, the temperature is reduced to 200°C and the furnace is taken out of the furnace, the temperature is kept warm for 16 hours, and the furnace is cooled to 100°C and the furnace is taken out of the furnace.

[0020] Preferably, the forging is preceded by at least two upsettings with a forging ratio of ≥6; during the upsetting, the upsetting ratio is ≥2, the final forging temperature is not less than 850°C, and the finishing temperature is not less than 800°C.

[0021] Preferably, after forging, air cooling is performed to 280-320° C., and then air cooling is performed to 280-320° C. before loading into the furnace.

[0022] (III) Beneficial effects

[0023] The present invention provides a high-toughness, corrosion-resistant, high-polishing nitrogen-containing stainless steel and a preparation method thereof. It has the following beneficial effects:

[0024] Through electric furnace smelting and controlling the nitrogen content, electrode blanks are made, and electroslag ingots are obtained by electroslag remelting. The finished product is obtained after forging and ultra-fine processing. Since the finished product has uniform composition, no obvious segregation, and low inclusion content, the material with guaranteed corrosion resistance, high hardness, polishability and toughness can be obtained through tempering, which can realize industrial mass production and the finished steel can reach more than 5 tons. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Embodiment 1:

[0027] The embodiment of the present invention provides a high-toughness, corrosion-resistant, high-polishing nitrogen-containing stainless steel, comprising:

[0028] Chromium is 12%, nickel is 4%, nitrogen is 0.1%, molybdenum is 0.5% and iron is 83.4%. The chromium content determines the corrosion resistance of stainless steel. The addition of nickel can improve the corrosion resistance and toughness of stainless steel. The addition of nitrogen can improve the hardness, strength and wear resistance of stainless steel. The addition of molybdenum can improve the corrosion resistance and strength of stainless steel.

[0029] A method for preparing high-toughness, corrosion-resistant and highly polished nitrogen-containing stainless steel comprises the following steps:

[0030] S1. Select the above raw materials, and smelt and cast them according to the above components to obtain nitrogen-containing electrode blanks, and anneal the electrode blanks.

[0031] S2. The electrode blank is remelted in an atmosphere-protected electroslag furnace to obtain a steel ingot, which is then annealed. The electroslag process is used for smelting, and the electroslag uses a ternary slag system and a multi-component slag system.

[0032] S3. Forge the steel ingot to obtain the forging blank and anneal it. Before forging, it shall be upset for at least twice and the forging ratio shall be ≥6. During upsetting, the upsetting ratio shall be ≥2. The final forging temperature shall be not less than 850℃ and the finishing temperature shall be not less than 800℃. After forging, it shall be air-cooled to 280-320℃ and then air-cooled to 280-320℃ before loading into the furnace.

[0033] S4. Perform ultra-fine processing on the forging blank.

[0034] S5. Spheroidizing annealing is performed on the steel billet after ultra-fine treatment, and steel is obtained after mechanical processing.

[0035] S6. Temper the steel and perform surface treatment such as polishing to obtain high hardness and high polishing surface.

[0036] S5. Test and quality control the prepared materials, including chemical composition analysis, metallographic microscope observation, and mechanical property testing, to ensure that the materials meet the specified requirements and standards. The electroslag ingot annealing process is divided into two stages, as follows: in the first stage, the furnace is loaded at 400℃, the temperature is evenly increased to 550℃ within two hours, and the temperature is kept for 3 hours. The temperature is evenly increased to 780℃ within 3 hours, and the temperature is kept for 18 hours. The temperature is evenly reduced to 550℃ within 12 hours, the natural gas furnace is turned off to cool, the temperature is reduced to 400℃, the fan is turned off to cool the furnace, and the temperature is reduced to 200℃ before being taken out of the furnace. In the second stage, the furnace is loaded at 200℃, the temperature is evenly increased to 450℃ within 4 hours, and the temperature is kept for 4 hours. The temperature is evenly increased to 730℃ within 6 hours, and the temperature is kept for 28 hours. The temperature is evenly reduced to 660℃ within 8 hours, and the temperature is kept for 16 hours. The furnace is cooled to 100℃ and taken out of the furnace.

[0037] Embodiment 2:

[0038] The embodiment of the present invention provides a high-toughness, corrosion-resistant, high-polishing nitrogen-containing stainless steel, comprising:

[0039] Chromium is 18%, nickel is 1%, nitrogen is 0.3%, molybdenum is 0.7% and iron is 80%. The chromium content determines the corrosion resistance of stainless steel. The addition of nickel can improve the corrosion resistance and toughness of stainless steel. The addition of nitrogen can improve the hardness, strength and wear resistance of stainless steel. The addition of molybdenum can improve the corrosion resistance and strength of stainless steel.

[0040] A method for preparing high-toughness, corrosion-resistant and highly polished nitrogen-containing stainless steel comprises the following steps:

[0041] S1. Select the above raw materials, and smelt and cast them according to the above components to obtain nitrogen-containing electrode blanks, and anneal the electrode blanks.

[0042] S2. The electrode blank is remelted in an atmosphere-protected electroslag furnace to obtain a steel ingot, which is then annealed. The electroslag process is used for smelting, and the electroslag uses a ternary slag system and a multi-component slag system.

[0043] S3. Forge the steel ingot to obtain the forging blank and anneal it. Before forging, it shall be upset for at least twice and the forging ratio shall be ≥6. During upsetting, the upsetting ratio shall be ≥2. The final forging temperature shall be not less than 850℃ and the finishing temperature shall be not less than 800℃. After forging, it shall be air-cooled to 280-320℃ and then air-cooled to 280-320℃ before loading into the furnace.

[0044] S4. Perform ultra-fine processing on the forging blank.

[0045] S5. Spheroidizing annealing is performed on the steel billet after ultra-fine treatment, and steel is obtained after mechanical processing.

[0046] S6. Temper the steel and perform surface treatment such as polishing to obtain high hardness and high polishing surface.

[0047] S5. Test and quality control the prepared materials, including chemical composition analysis, metallographic microscope observation, and mechanical property testing, to ensure that the materials meet the specified requirements and standards. The electroslag ingot annealing process is divided into two stages, as follows: in the first stage, the furnace is loaded at 400℃, the temperature is evenly increased to 550℃ within two hours, and the temperature is kept for 3 hours. The temperature is evenly increased to 780℃ within 3 hours, and the temperature is kept for 18 hours. The temperature is evenly reduced to 550℃ within 12 hours, the natural gas furnace is turned off to cool, the temperature is reduced to 400℃, the fan is turned off to cool the furnace, and the temperature is reduced to 200℃ before being taken out of the furnace. In the second stage, the furnace is loaded at 200℃, the temperature is evenly increased to 450℃ within 4 hours, and the temperature is kept for 4 hours. The temperature is evenly increased to 730℃ within 6 hours, and the temperature is kept for 28 hours. The temperature is evenly reduced to 660℃ within 8 hours, and the temperature is kept for 16 hours. The furnace is cooled to 100℃ and taken out of the furnace.

[0048] Embodiment three:

[0049] The embodiment of the present invention provides a high-toughness, corrosion-resistant, high-polishing nitrogen-containing stainless steel, comprising:

[0050] Chromium is 12%, nickel is 4%, nitrogen is 0.3%, molybdenum is 3% and iron is 80.7%. The chromium content determines the corrosion resistance of stainless steel. The addition of nickel can improve the corrosion resistance and toughness of stainless steel. The addition of nitrogen can improve the hardness, strength and wear resistance of stainless steel. The addition of molybdenum can improve the corrosion resistance and strength of stainless steel.

[0051] A method for preparing high-toughness, corrosion-resistant and highly polished nitrogen-containing stainless steel comprises the following steps:

[0052] S1. Select the above raw materials, and smelt and cast them according to the above components to obtain nitrogen-containing electrode blanks, and anneal the electrode blanks.

[0053] S2. The electrode blank is remelted in an atmosphere-protected electroslag furnace to obtain a steel ingot, which is then annealed. The electroslag process is used for smelting, and the electroslag uses a ternary slag system and a multi-component slag system.

[0054] S3. Forge the steel ingot to obtain the forging blank and anneal it. Before forging, it shall be upset for at least twice and the forging ratio shall be ≥6. During upsetting, the upsetting ratio shall be ≥2. The final forging temperature shall be not less than 850℃ and the finishing temperature shall be not less than 800℃. After forging, it shall be air-cooled to 280-320℃ and then air-cooled to 280-320℃ before loading into the furnace.

[0055] S4. Perform ultra-fine processing on the forging blank.

[0056] S5. Spheroidizing annealing is performed on the steel billet after ultra-fine treatment, and steel is obtained after mechanical processing.

[0057] S6. Temper the steel and perform surface treatment such as polishing to obtain high hardness and high polishing surface.

[0058] S5. Test and quality control the prepared materials, including chemical composition analysis, metallographic microscope observation, and mechanical property testing, to ensure that the materials meet the specified requirements and standards. The electroslag ingot annealing process is divided into two stages, as follows: in the first stage, the furnace is loaded at 400℃, the temperature is evenly increased to 550℃ within two hours, and the temperature is kept for 3 hours. The temperature is evenly increased to 780℃ within 3 hours, and the temperature is kept for 18 hours. The temperature is evenly reduced to 550℃ within 12 hours, the natural gas furnace is turned off to cool, the temperature is reduced to 400℃, the fan is turned off to cool the furnace, and the temperature is reduced to 200℃ before being taken out of the furnace. In the second stage, the furnace is loaded at 200℃, the temperature is evenly increased to 450℃ within 4 hours, and the temperature is kept for 4 hours. The temperature is evenly increased to 730℃ within 6 hours, and the temperature is kept for 28 hours. The temperature is evenly reduced to 660℃ within 8 hours, and the temperature is kept for 16 hours. The furnace is cooled to 100℃ and taken out of the furnace.

[0059] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-toughness, corrosion-resistant, high-polishing nitrogen-containing stainless steel, characterized in that: include: Chromium is 12%-25%, nickel is 0.25%-4%, nitrogen is 0.1%-0.3%, molybdenum is 0.5%-3%, and iron is 80%-85%.

2. The high-toughness, corrosion-resistant, high-polishing nitrogen-containing stainless steel according to claim 1, characterized in that: The nitrogen content is controlled at 1200ppm-1300ppm.

3. A method for preparing high-toughness, corrosion-resistant, high-polishing nitrogen-containing stainless steel, characterized in that: The following steps are involved: S1. Select the above raw materials, and smelt and cast them according to the above components to obtain nitrogen-containing electrode blanks, and anneal the electrode blanks; S2, remelting the electrode blank in an atmosphere-protected electroslag furnace to obtain a steel ingot, and annealing the steel ingot; S3, forging the steel ingot to obtain a forging blank and annealing it; S4, ultra-fine treatment of forging blank; S5, spheroidizing annealing the steel billet after ultra-fine treatment, and obtaining steel after mechanical processing; S6. Temper the steel and perform surface treatment such as polishing to obtain high hardness and high polishing surface; S5. Conduct testing and quality control on the prepared materials, including chemical composition analysis, metallographic microscope observation, and mechanical property testing to ensure that the materials meet the specified requirements and standards.

4. The method for preparing high-toughness, corrosion-resistant, high-polishing nitrogen-containing stainless steel according to claim 3, characterized in that: The smelting adopts an electroslag process, and the electroslag adopts a ternary slag system and a multi-component slag system.

5. The method for preparing high-toughness, corrosion-resistant, high-polishing nitrogen-containing stainless steel according to claim 3, characterized in that: The electroslag ingot annealing process is divided into two stages, which are as follows: in the first stage, the furnace is loaded at 400°C, the temperature is evenly increased to 550°C within two hours, the temperature is kept for 3 hours, the temperature is evenly increased to 780°C within 3 hours, the temperature is kept for 18 hours, the temperature is evenly reduced to 550°C within 12 hours, the natural gas furnace is turned off to cool, the temperature is reduced to 400°C, the fan furnace is turned off to cool, the temperature is reduced to 200°C and the furnace is taken out; in the second stage, the furnace is loaded at 200°C, the temperature is evenly increased to 450°C within 4 hours, the temperature is kept for 4 hours, the temperature is evenly increased to 730°C within 6 hours, the temperature is kept for 28 hours, the temperature is evenly reduced to 660°C within 8 hours, the temperature is kept for 16 hours, the furnace is cooled to 100°C and the furnace is taken out.

6. The method for preparing high-toughness, corrosion-resistant, high-polishing nitrogen-containing stainless steel according to claim 3, characterized in that: The forging is preceded by no less than two upsettings with a forging ratio of ≥6; during the upsetting, the upsetting ratio is ≥2, the final forging temperature is not less than 850°C, and the finishing temperature is not less than 800°C.

7. The method for preparing high-toughness, corrosion-resistant, high-polishing nitrogen-containing stainless steel according to claim 3, characterized in that: After forging, the steel is subjected to air cooling to 280-320° C., and then air cooling to 280-320° C. before being loaded into a furnace.