High-toughness alloy steel and preparation method thereof

Abstract

The invention discloses high-toughness alloy steel and a preparation method thereof. The invention relates to the technical field of metal preparation. The expression formula of alloy steel is as follows: Fe <-0.15 > C <-1.5 > Mn <-0.5 > Si <-0.3 > Cr <-0.1 > Ni <-0.5 > Mo <-0.2 > V <-0.03 > Nb <-B-xAl. Compared with the prior art, according to the high-toughness alloy steel and the preparation method thereof, in the smelting process, the temperature control accuracy can be improved by controlling the temperature of the electric arc furnace, and therefore the performance of the alloy steel is guaranteed. In the smelting process, vacuum deoxidation treatment is carried out, a proper amount of aluminum material is added, and vacuum degassing treatment is carried out, so that the content of oxygen and gas in molten steel can be reduced, and the purity and performance of the alloy steel are improved. After smelting is completed, molten steel is subjected to electromagnetic stirring and ultrasonic treatment, the liquidity of the molten steel can be improved, uniform distribution of alloy elements is promoted, and the performance of the alloy steel is improved. The casting mould is preheated before casting, and quenching and tempering are carried out after casting is completed, so that the performance and quality of the casting can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of metal preparation, in particular to a high-toughness alloy steel and a preparation method thereof. Background Art

[0002] High-toughness alloy steel plays an important role in modern industry. It is widely used in aerospace, automobile manufacturing, engineering machinery and other fields. These fields have extremely high requirements for materials, requiring materials to have high strength and good toughness. However, there are some limitations in the traditional preparation methods of alloy steel, which limit the further improvement of material performance. During use, high-toughness alloy steel usually faces the following problems: 1. Traditional preparation methods are difficult to accurately control the chemical composition of alloy steel, resulting in large fluctuations in performance. 2. The temperature control accuracy during the smelting process is insufficient, which affects the performance of the alloy steel. 3. Traditional vacuum treatment methods are difficult to effectively reduce the oxygen and gas content in the molten steel, affecting the purity and performance of the alloy steel. 4. The heat treatment after casting is difficult to achieve ideal performance, affecting the overall performance of the alloy steel. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention provides a high-toughness alloy steel and a preparation method thereof, which solves the problem of low performance of the existing high-toughness alloy steel.

[0004] To achieve the above-mentioned purpose, the present invention is implemented through the following technical scheme: a high-toughness alloy steel, the expression of the alloy steel is: Fe-0.15C-1.5Mn-0.5Si-0.3Cr-0.1Ni-0.5Mo-0.2V-0.03Nb-B-xAl, wherein x=0.01-1.5%.

[0005] Preferably, the boron content is 0.0005-0.005%.

[0006] The present application also provides a method for preparing high-toughness alloy steel, comprising the following steps:

[0007] S1. According to the chemical composition expression of alloy steel Fe-0.15C-1.5Mn-0.5Si-0.3Cr-0.1Ni-0.5Mo-0.2V-0.03Nb-B-xAl, prepare raw materials of corresponding mass proportion, including iron material, carbon powder, manganese material, ferrosilicon, ferrochrome, nickel plate, ferromolybdenum, ferrovanadium, ferroniobium, ferroboron and aluminum material, and dry the raw materials to remove moisture and oil stains;

[0008] S2. Add the prepared iron and other alloying elements into the electric arc furnace in a certain order. When smelting begins, add the iron first, followed by carbon powder, manganese, ferrosilicon, ferrochrome, nickel plate, ferromolybdenum, ferrovanadium and ferroniobium. During the smelting process, control the temperature of the electric arc furnace between 1600-1650℃.

[0009] S3, during the smelting process, vacuum deoxidation treatment is performed, and an appropriate amount of aluminum material is added; at the same time, vacuum degassing treatment is performed to reduce the gas content in the molten steel; wherein the final aluminum content is between 0.01-1.5%;

[0010] S4. After smelting is completed, the molten steel is electromagnetically stirred;

[0011] S5, pouring the electromagnetically stirred molten steel into a preheated casting mold for casting;

[0012] S6. Quench and temper the cast alloy steel.

[0013] Preferably, in step S1, the drying process comprises using a drying device to dry the raw material at a temperature of 100-150° C. for at least 2 hours.

[0014] Preferably, in step S2, the order of adding alloy elements is: first add carbon powder, then add manganese material, ferrosilicon, ferrochrome, nickel plate, ferromolybdenum, ferrovanadium and ferroniobium in sequence, and finally add ferroboron.

[0015] Preferably, in step S3, the vacuum degree of the vacuum deoxidation treatment is controlled at 0.1-0.5 Torr.

[0016] Preferably, in step S4, the frequency of electromagnetic stirring is controlled at 5-50 Hz, and the stirring time lasts for 5-15 minutes.

[0017] Preferably, ultrasonic treatment is performed after electromagnetic stirring, and the ultrasonic action time is greater than 90 seconds.

[0018] Preferably, in step S5, the preheating temperature of the mold before casting is controlled at 200-300°C to reduce thermal stress during the cooling process of the casting.

[0019] Preferably, in step S6, the quenching temperature is controlled at 900-1050°C, and the tempering temperature is controlled at 550-650°C.

[0020] Beneficial effects of the present invention: By using a high-toughness alloy steel and a preparation method thereof provided by the present invention, compared with the prior art, during the smelting process, by controlling the temperature of the electric arc furnace, the accuracy of temperature control can be improved, thereby ensuring the performance of the alloy steel. During the smelting process, vacuum deoxidation treatment is performed, an appropriate amount of aluminum material is added, and vacuum degassing treatment is performed, which can reduce the oxygen and gas content in the molten steel and improve the purity and performance of the alloy steel. After the smelting is completed, electromagnetic stirring and ultrasonic treatment are performed on the molten steel, which can improve the fluidity of the molten steel, promote the uniform distribution of alloy elements, and improve the performance of the alloy steel. Preheating the mold before casting, and quenching and tempering after casting are completed, can improve the performance and quality of the casting. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the surface texture of the high-toughness alloy steel of the present invention. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. As long as the effects of the present invention can be exerted, various changes can be made to the implementation scheme.

[0023] A high-toughness alloy steel, the alloy steel has the following formula: Fe-0.15C-1.5Mn-0.5Si-0.3Cr-0.1Ni-0.5Mo-0.2V-0.03Nb-B-xAl, wherein x=0.01-1.5%, and the boron content is 0.0005-0.005%.

[0024] The chemical composition of the thick high-toughness alloy steel plate of the present invention is determined as follows:

[0025] Iron (Fe): As a matrix element, it provides strength and toughness to the alloy.

[0026] Carbon (C): mainly forms carbides with other elements, plays the role of organizational strengthening and precipitation strengthening, and can significantly improve strength and hardness. But it may also reduce toughness, so the C content is controlled at 0.07-0.15%.

[0027] Manganese (Mn): Manganese is an alloying element used to increase the strength and toughness of the alloy while improving welding performance. Manganese can also form manganese sulfide with sulfur to reduce the harm of sulfur. The manganese content is usually controlled at 1-2%. In this alloy steel, the manganese content is 1.5%.

[0028] Silicon (Si): Silicon can increase the strength of the alloy and improve toughness. Silicon can also promote the formation of ferrite, thereby improving toughness. The silicon content is usually controlled at 0.5-1%. In this alloy steel, the silicon content is 0.5%.

[0029] Chromium (Cr): Chromium can improve the corrosion resistance of the alloy and improve wear resistance. Chromium can also form chromium carbide with carbon to improve hardness and wear resistance. The chromium content is usually controlled at 0.2-0.5%. In this alloy steel, the chromium content is 0.3%.

[0030] Nickel (Ni): Nickel can improve the toughness of the alloy and improve welding performance. Nickel can also form nickel carbide with carbon to improve hardness and wear resistance. The nickel content is usually controlled at 0.1-0.5%. In this alloy steel, the nickel content is 0.1%.

[0031] Molybdenum (Mo): Molybdenum can improve the strength and toughness of the alloy, while improving corrosion resistance. Molybdenum can also form molybdenum carbide with carbon to improve hardness and wear resistance. The content of molybdenum is usually controlled at 0.2-0.5%. In this alloy steel, the content of molybdenum is 0.5%.

[0032] Vanadium (V): Vanadium can improve the strength and toughness of the alloy, while improving corrosion resistance. Vanadium can also form vanadium carbide with carbon to improve hardness and wear resistance. The vanadium content is usually controlled at 0.1-0.5%. In this alloy steel, the vanadium content is 0.2%.

[0033] Niobium (Nb): Niobium can improve the strength and toughness of the alloy, while improving corrosion resistance. Niobium can also form niobium carbide with carbon to improve hardness and wear resistance. The niobium content is usually controlled at 0.01-0.05%. In this alloy steel, the niobium content is 0.03%.

[0034] Boron (B): Boron can refine grains and improve the strength and toughness of alloys. Boron can also form boronized carbon with carbon to improve hardness and wear resistance. The content of boron is usually controlled at 0.0005-0.005%. In this alloy steel, the content of boron is 0.0005%.

[0035] Aluminum (Al): Aluminum can improve the strength and toughness of the alloy, while improving corrosion resistance. Aluminum can also form aluminized carbon with carbon to improve hardness and wear resistance. The aluminum content is usually controlled at 0.01-1.5%. In this alloy steel, the aluminum content is X%. X is the remaining amount of the high-toughness alloy steel plate.

[0036] The present invention also provides a method for preparing high-toughness alloy steel, comprising the following steps:

[0037] S1. According to the chemical composition expression of alloy steel Fe-0.15C-1.5Mn-0.5Si-0.3Cr-0.1Ni-0.5Mo-0.2V-0.03Nb-B-xAl, prepare raw materials of corresponding mass proportion, including iron material, carbon powder, manganese material, ferrosilicon, ferrochrome, nickel plate, ferromolybdenum, ferrovanadium, ferroniobium, ferroboron and aluminum material, and dry the raw materials;

[0038] The drying process includes drying the raw materials at a temperature of 100-150° C. for at least 2 hours using a drying device.

[0039] In this step, the moisture and oil in the raw materials are removed through drying to avoid affecting the chemical composition and properties of the alloy steel during the smelting process. Ensure that the raw materials are dry to provide pure raw materials for the subsequent smelting process. Ensure that the drying temperature and time are appropriate to avoid over-drying or incomplete drying of the raw materials.

[0040] S2. Add the prepared iron and other alloying elements into the electric arc furnace in a certain order. When smelting begins, add the iron first, followed by carbon powder, manganese, ferrosilicon, ferrochrome, nickel plate, ferromolybdenum, ferrovanadium and ferroniobium. During the smelting process, control the temperature of the electric arc furnace between 1600-1650℃.

[0041] The order of adding alloying elements is: first add carbon powder, then add manganese material, ferrosilicon, ferrochrome, nickel plate, ferromolybdenum, ferrovanadium and ferroniobium in sequence, and finally add ferroboron.

[0042] By controlling the melting temperature and the order of adding alloy elements, the uniformity of alloy steel composition and the stability of the melting process are ensured, and high-toughness alloy steel with uniform composition and stable performance is obtained.

[0043] It is important to ensure that the temperature of the arc furnace is controlled within an appropriate range to avoid excessively high or low temperatures.

[0044] S3. During the smelting process, vacuum deoxidation treatment is performed and an appropriate amount of aluminum material is added; at the same time, vacuum degassing treatment is performed to reduce the gas content in the molten steel; wherein the final aluminum content is between 0.01-1.5%; and the vacuum degree of vacuum deoxidation treatment is controlled at 0.1-0.5 Torr.

[0045] Through vacuum deoxidation and degassing treatment, the oxygen and gas content in the molten steel is reduced, and the purity and performance of the alloy steel are improved. In this way, high-toughness alloy steel with high purity and excellent performance is obtained.

[0046] S4. After smelting is completed, the molten steel is subjected to electromagnetic stirring; the frequency of the electromagnetic stirring is controlled at 5-50 Hz, and the stirring time lasts for 5-15 minutes. After the electromagnetic stirring, ultrasonic treatment is performed, and the ultrasonic action time is greater than 90 seconds.

[0047] Through electromagnetic stirring and ultrasonic treatment, the fluidity of molten steel is improved, the uniform distribution of alloy elements is promoted, and the performance of alloy steel is improved. High-toughness alloy steel with good fluidity and uniform composition is obtained.

[0048] S5. Pour the electromagnetically stirred molten steel into a preheated casting mold for casting; the preheating temperature of the casting mold is controlled at 200-300° C. before casting to reduce thermal stress during the cooling process of the casting.

[0049] By preheating the casting mold, the thermal stress during the cooling process of the casting is reduced, the performance of the casting is improved, and high-toughness alloy steel castings with stable performance are obtained.

[0050] S6. Quench and temper the cast alloy steel. The quenching temperature is controlled at 900-1050°C, and the tempering temperature is controlled at 550-650°C.

[0051] Through quenching and tempering treatment, the performance of alloy steel is improved and its toughness is increased, so that alloy steel with high toughness and excellent performance is obtained.

[0052] This preparation method achieves the preparation of high-toughness alloy steel by precisely controlling key steps such as raw material drying, smelting temperature, order of adding alloy elements, vacuum deoxidation and degassing treatment, electromagnetic stirring and ultrasonic treatment, preheating mold, quenching and tempering temperature, and has the advantages of simple operation and stable performance.

[0053] 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 alloy steel, characterized in that: The alloy steel has the formula: Fe-0.15C-1.5Mn-0.5Si-0.3Cr-0.1Ni-0.5Mo-0.2V-0.03Nb-B-xAl, wherein x=0.01-1.5%.

2. The high-toughness alloy steel according to claim 1, characterized in that: The boron content is 0.0005-0.005%.

3. A method for preparing high-toughness alloy steel, characterized in that: The following steps are involved: S1. According to the chemical composition expression of alloy steel Fe-0.15C-1.5Mn-0.5Si-0.3Cr-0.1Ni-0.5Mo-0.2V-0.03Nb-B-xAl, prepare raw materials of corresponding mass proportion, including iron material, carbon powder, manganese material, ferrosilicon, ferrochrome, nickel plate, ferromolybdenum, ferrovanadium, ferroniobium, ferroboron and aluminum material, and dry the raw materials to remove moisture and oil stains; S2. Add the prepared iron and other alloying elements into the electric arc furnace in a certain order. When smelting begins, add the iron first, followed by carbon powder, manganese, ferrosilicon, ferrochrome, nickel plate, ferromolybdenum, ferrovanadium and ferroniobium. During the smelting process, control the temperature of the electric arc furnace between 1600-1650℃. S3, during the smelting process, vacuum deoxidation treatment is performed, and an appropriate amount of aluminum material is added; at the same time, vacuum degassing treatment is performed to reduce the gas content in the molten steel; wherein the final aluminum content is between 0.01-1.5%; S4. After smelting is completed, the molten steel is subjected to electromagnetic stirring; S5, pouring the electromagnetically stirred molten steel into a preheated casting mold for casting; S6. Quench and temper the cast alloy steel.

4. The method for preparing a high-toughness alloy steel according to claim 3, characterized in that: In step S1, the drying process includes using a drying device to dry the raw material at a temperature of 100-150° C. for at least 2 hours.

5. The method for preparing a high-toughness alloy steel according to claim 3, characterized in that: In step S2, the order of adding alloy elements is: first add carbon powder, then add manganese material, ferrosilicon, ferrochrome, nickel plate, ferromolybdenum, ferrovanadium and ferroniobium in sequence, and finally add ferroboron.

6. The method for preparing a high-toughness alloy steel according to claim 3, characterized in that: In step S3, the vacuum degree of the vacuum deoxidation treatment is controlled at 0.1-0.5 Torr.

7. The method for preparing a high-toughness alloy steel according to claim 3, characterized in that: In step S4, the frequency of electromagnetic stirring is controlled at 5-50 Hz, and the stirring time lasts for 5-15 minutes.

8. The method for preparing a high-toughness alloy steel according to claim 7, characterized in that: After electromagnetic stirring, ultrasonic treatment is performed, and the ultrasonic action time is greater than 90s.

9. The method for preparing a high-toughness alloy steel according to claim 3, characterized in that: In step S5, the preheating temperature of the casting mold is controlled at 200-300°C before casting to reduce thermal stress during the cooling process of the casting.

10. The method for preparing a high-toughness alloy steel according to claim 3, characterized in that: In step S6, the quenching temperature is controlled at 900-1050°C, and the tempering temperature is controlled at 550-650°C.

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