A wear-resistant, ductile steel and a method of making and using the same

Abstract

The application belongs to the technical field of alloys, and discloses a wear-resistant and tough steel as well as a preparation method and application thereof. The steel comprises, in terms of mass fraction, Cr 4.8-10.2%, Mo 0.8-2.5%, V 1.5-3.5%, C 0.8-1.5%, Si 0.8-1.8%, Mn 0.3-0.8%, Fe 79.7-90.7%, and inevitable impurities. The steel of the application is composed of Cr, Mo, V, C, Si, Mn and Fe with specific components and contents, so that the steel can meet the requirements of wear resistance and high toughness at the same time. The transverse impact energy of the 10*10*55mm unnotched Charpy impact specimen of the steel is 30-50J, and the longitudinal impact energy is 60-90J when the hardness is HRC60-64.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of alloy, in particular relates to a kind of wear-resistant, tough steel and its preparation method and application. BACKGROUND

[0002] The existing steel material is widely used, for example, is made into various parts, is used as cutter or die.This requires steel to have good wear resistance and toughness.General steel has high hardness, which is beneficial to improve wear resistance.But improve wear resistance, toughness is often poor.

[0003] Therefore, it is urgent to provide a new steel material, which can meet the high wear resistance and high toughness performance. SUMMARY

[0004] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application proposes a kind of wear-resistant, tough steel and its preparation method and application. The steel described in the present application has high hardness, thereby having good wear resistance, and at the same time also meets the requirement of good toughness performance.

[0005] The inventive concept of the present application: the steel described in the present application is composed of Cr, Mo, V, C, Si, Mn and Fe with specific components and contents, so that the steel can meet the requirements of wear resistance and high toughness at the same time.

[0006] The first aspect of the present application provides a kind of wear-resistant, tough steel.

[0007] Specifically, a kind of wear-resistant, tough steel, according to mass fraction, includes Cr 4.8-10.2%, Mo 0.8-2.5%, V1.5-3.5%, C 0.8-1.5%, Si 0.8-1.8%, Mn 0.3-0.8%, Fe 79.7-90.7%, and inevitable impurities.

[0008] Preferably, the steel, according to mass fraction, includes Cr 5.0-10.0%, Mo 1.0-2.0%, V 1.5-3.0%, C 0.8-1.5%, Si 0.8-1.5%, Mn 0.3-0.8%, Fe 81.2-85.1%, and inevitable impurities.

[0009] Preferably, the inevitable impurities include P and / or S.

[0010] Preferably, the mass fraction of the inevitable impurities is less than or equal to 0.1%, and further preferably less than or equal to 0.03%.

[0011] Preferably, the content of P is less than or equal to 0.055%, and further preferably less than or equal to 0.025%.

[0012] Preferably, the content of S is less than or equal to 0.045%, and more preferably less than or equal to 0.015%.

[0013] Preferably, the Rockwell hardness of the steel after quenching and tempering heat treatment is HRC60-64.

[0014] Preferably, the transverse impact energy of a 10×10×55mm unnotched Charpy impact test specimen of the steel at a hardness of HRC60-64 is 30-50J, and the longitudinal impact energy is 60-90J.

[0015] A second aspect of the present invention provides a method for preparing wear-resistant and tough steel.

[0016] Specifically, a method for preparing a wear-resistant and tough steel includes the following steps:

[0017] (1) Steel smelting: Weigh the raw material components, mix them, and smelt them to obtain molten steel;

[0018] (2) Spray forming: The molten steel is sprayed into steel ingots;

[0019] (3) Forging and heat treatment: The steel ingot is forged, then annealed, and after rough machining, it is quenched, tempered and cryogenically treated to obtain the steel.

[0020] Preferably, in step (1), the melting is carried out under a protective atmosphere, which includes nitrogen or a rare gas (e.g., argon).

[0021] Preferably, in step (1), the melting temperature is 1600-1650℃, more preferably 1620-1650℃. At this temperature, the molten steel is superheated and mixed evenly.

[0022] Preferably, in step (1), the smelting is carried out in an induction furnace, and the furnace lining of the induction furnace is alkaline or weakly alkaline.

[0023] Preferably, in step (2), the process conditions during the spray forming process are as follows: the flow rate of molten steel is 40-160 kg / min, the atomizing gas is nitrogen, the working pressure is 4-14 atm, and the molten steel is atomized into 5-150 μm particles and sprayed onto the deposition plate at a speed of 100-300 m / s to form a cylindrical steel ingot. The cooling rate of the spray-formed molten steel is approximately 10,000 degrees / second, which is on the order of 10,000 times that of traditional ingot casting or electroslag remelting and other metallurgical processes. The resulting steel ingot has no macroscopic segregation and a fine and uniform grain structure.

[0024] More preferably, the process conditions during the spray forming process are as follows: the flow rate of molten steel is 50-150 kg / min, the atomizing gas is nitrogen, the working pressure is 6-12 atm, and the molten steel is atomized into 10-100μm particles and sprayed onto the deposition plate at a speed of 200-300 m / s to form a cylindrical steel ingot.

[0025] Spray forming involves spraying using existing spray forming machines.

[0026] Preferably, in step (3), the starting temperature of forging is 1100-1180℃, and the ending temperature of forging is 800-880℃; more preferably, the starting temperature of forging is 1160-1180℃, and the ending temperature of forging is 830-860℃. Forging can produce steel billet forgings of various shapes.

[0027] Preferably, in step (3), the annealing process is as follows: holding at 840-890℃ for 3-5 hours, then cooling at a rate of 10-15℃ / h to 700-780℃ and holding for 2-4 hours, then furnace cooling to 500-700℃ and finally air cooling to a hardness ≤220HB; more preferably, the annealing process is as follows: holding at 870-880℃ for 3-5 hours, then cooling at a rate of 12-15℃ / h to 740-750℃ and holding for 2-4 hours, then furnace cooling to 550-600℃ and finally air cooling to a hardness ≤220HB.

[0028] Preferably, in step (3), the quenching is performed by vacuum oil quenching. The austenitizing temperature of the corresponding steel part before vacuum oil quenching is 1050-1100℃.

[0029] Preferably, in step (3), the tempering is performed at 500-550℃ for 2-8 hours; for workpieces with a wall thickness greater than 30mm, the tempering is performed at 510-550℃ for 4-8 hours.

[0030] Preferably, in step (3), the cryogenic treatment is performed at -90°C for 2-10 hours; more preferably, the cryogenic treatment is performed at -160°C for 4-8 hours depending on the workpiece wall thickness.

[0031] Preferably, after cryogenic and tempering treatment, the steel parts can be precision machined as needed.

[0032] A third aspect of the invention provides the application of the aforementioned wear-resistant and tough steel.

[0033] A component comprising the aforementioned steel.

[0034] Preferably, the components include any one of cutting tools, screws, dies, and cold rolling rolls. Specifically, examples include stamping or forming dies, slitting knives, shearing knives, thread rolling knives, wear parts for engineering machinery, woodworking tools, ceramic and metal powder pressing dies, precision blanking dies, cold heading dies, injection molding feed screws and tips, high-end hand tools, waste shredders, and cold rolling rolls.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] The steel described in this invention is composed of specific components and contents of Cr, Mo, V, C, Si, Mn, and Fe, enabling it to simultaneously meet the requirements of wear resistance and high toughness. A 10×10×55mm unnotched Charpy impact specimen with a Rockwell hardness of HRC60-64 exhibits a transverse impact energy of 30-50 J and a longitudinal impact energy of 60-90 J. Attached Figure Description

[0037] Figure 1 This is a metallographic diagram of the steel in Example 1 of the present invention;

[0038] Figure 2 This is a metallographic diagram of the steel used in Comparative Example 1 of this invention;

[0039] Figure 3 This is a metallographic diagram of the steel used in Comparative Example 2 of this invention;

[0040] Figure 4 This is a metallographic diagram of the steel used in Comparative Example 3 of this invention. Detailed Implementation

[0041] To enable those skilled in the art to more clearly understand the technical solutions described in this invention, the following embodiments are provided for illustration. It should be noted that the following embodiments do not constitute a limitation on the scope of protection claimed by this invention.

[0042] Unless otherwise specified, the raw materials, reagents or devices used in the following examples are available from conventional commercial sources or can be obtained by existing known methods.

[0043] Example 1: Preparation of wear-resistant and tough steel

[0044] A wear-resistant and tough steel comprising, by mass fraction, 7.8% Cr, 1.6% Mo, 2.4% V, 1.1% C, 1.2% Si, 0.4% Mn, balance Fe, and unavoidable impurities.

[0045] Unavoidable impurities include P and S.

[0046] A method for preparing wear-resistant and tough steel includes the following steps:

[0047] (1) Steel melting: Weigh the raw material components according to the content of each component in the target steel, mix them, and melt them in an induction furnace under a protective atmosphere of nitrogen. The melting temperature is 1630℃ to obtain molten steel.

[0048] (2) Spray forming: The existing spray forming machine is used to spray molten steel into steel ingots. The process conditions during the spray forming process are: the flow rate of molten steel is 100 kg / min, the atomizing gas is nitrogen, the working pressure is 8 atmospheres, and the molten steel is atomized into 40-150μm particles and sprayed onto the deposition plate at a speed of 250 m / s to form cylindrical steel ingots.

[0049] (3) Forging and heat treatment: The steel ingot is forged at a starting temperature of 1170℃ and a ending temperature of 860℃. Then it is annealed. The annealing process is as follows: hold at 860℃ for 3 hours, then cool to 720℃ at a cooling rate of 15℃ / h and hold for 3 hours, then furnace cool to 550℃ and take out of the furnace, and finally air cool to a hardness of 200-205HB. Then it is quenched by vacuum oil quenching at a quenching temperature of 1050℃. Tempering is carried out by holding at 510℃ for 4 hours. Cryogenic treatment is carried out by holding at -120℃ for 5 hours to obtain a rod-shaped steel part with a hardness of HRC62.

[0050] Example 2: Preparation of wear-resistant and tough steel

[0051] A wear-resistant and tough steel comprising, by mass fraction, 5.5% Cr, 1.8% Mo, 2.8% V, 1.4% C, 0.9% Si, 0.7% Mn, balance Fe, and unavoidable impurities.

[0052] Unavoidable impurities include P and S.

[0053] A method for preparing wear-resistant and tough steel includes the following steps:

[0054] (1) Steel melting: Weigh the raw material components according to the content of each component in the target steel, mix them, and melt them in an induction furnace under a protective atmosphere of nitrogen at a melting temperature of 1650℃ to obtain molten steel.

[0055] (2) Spray forming: The existing spray forming machine is used to spray molten steel into steel ingots. The process conditions during the spray forming process are: the flow rate of molten steel is 120 kg / min, the atomizing gas is nitrogen, the working pressure is 9 atmospheres, and the molten steel is atomized into 30-100μm particles and sprayed onto the deposition plate at a speed of 260 m / s to form cylindrical steel ingots.

[0056] (3) Forging and heat treatment: The steel ingot is forged at a starting temperature of 1160℃ and a ending temperature of 850℃. Then it is annealed. The annealing process is as follows: hold at 850℃ for 4 hours, then cool to 730℃ at a cooling rate of 14℃ / h and hold for 3 hours, then furnace cool to 560℃ and take out of the furnace. Finally, air cool to a hardness of ≤220HB and then quench. The quenching is carried out by vacuum oil quenching at a quenching temperature of 1080℃. Tempering is carried out at 530℃ for 4 hours. Cryogenic treatment is carried out at -90℃ for 6 hours to obtain bar-shaped steel with a hardness of HRC62.

[0057] Example 3: Preparation of wear-resistant and tough steel

[0058] A wear-resistant and tough steel comprising, by mass fraction, 9.5% Cr, 1.1% Mo, 2.0% V, 1.0% C, 0.8% Si, 0.5% Mn, balance Fe, and unavoidable impurities.

[0059] Unavoidable impurities include P and S.

[0060] A method for preparing wear-resistant and tough steel includes the following steps:

[0061] (1) Steel melting: Weigh the raw material components according to the content of each component in the target steel, mix them, and melt them in an induction furnace under a protective atmosphere of nitrogen. The melting temperature is 1640℃ to obtain molten steel.

[0062] (2) Spray forming: The existing spray forming machine is used to spray molten steel into steel ingots. The process conditions during the spray forming process are: the flow rate of molten steel is 110 kg / min, the atomizing gas is nitrogen, the working pressure is 10 atmospheres, and the molten steel is atomized into 20-60μm particles and sprayed onto the deposition plate at a speed of 270 m / s to form cylindrical steel ingots.

[0063] (3) Forging and heat treatment: The steel ingot is forged at a starting temperature of 1180℃ and a ending temperature of 840℃. Then it is annealed. The annealing process is as follows: hold at 840℃ for 5 hours, then cool to 720℃ at a cooling rate of 12℃ / h and hold for 3 hours, then furnace cool to 550℃ and take out of the furnace. Finally, air cool to a hardness of ≤220HB and then quench. The quenching is carried out by vacuum oil quenching at a quenching temperature of 1080℃. Tempering is carried out at 530℃ for 4 hours. Cryogenic treatment is carried out at -90℃ for 8 hours to obtain bar-shaped steel with a hardness of HRC63.5.

[0064] Comparative Example 1

[0065] Compared to Example 1, the steel of Comparative Example 1, by mass fraction, includes 12% Cr, 0.8% Mo, 0.8% V, 1.5% C, 0.5% Si, 0.4% Mn, the balance Fe, and unavoidable impurities. Unavoidable impurities include P and S. The steel of Comparative Example 1 was prepared in the same manner as in Example 1, except for the different raw material proportions; the resulting steel is called PSF1211.

[0066] Comparative Example 2

[0067] Compared to Example 1, the steel of Comparative Example 2, by mass fraction, includes 8.0% Cr, 2.0% Mo, 0.25% V, 1.0% C, 1.0% Si, 0.4% Mn, the balance Fe, and unavoidable impurities. Unavoidable impurities include P and S. The steel of Comparative Example 2 was prepared in the same manner as in Example 1, except for the different raw material proportions; the resulting steel is called PSF1820.

[0068] Comparative Example 3

[0069] Compared to Example 1, the steel of Comparative Example 3, by mass fraction, includes 7.8% Cr, 1.6% Mo, 3.8% V, 1.1% C, 1.2% Si, 0.4% Mn, the balance Fe, and unavoidable impurities. Unavoidable impurities include P and S. The steel of Comparative Example 3 was prepared in the same manner as in Example 1, except for the different raw material proportions; the resulting steel is called PSF1824.

[0070] Product effectiveness test

[0071] 1. Metallographic structure test

[0072] Take the above-mentioned rod-shaped steel (200 mm in diameter) from Example 1 and Comparative Examples 1-2, immerse them in a 3% (w / w) nitric acid-alcohol mixture for etching, and then obtain metallographic samples longitudinally at half the radius of the rod to obtain the metallographic microstructure of the steel from Example 1 and Comparative Examples 1-3. The results are as follows: Figures 1-4 As shown.

[0073] Figure 1 This is a metallographic diagram of the steel in Example 1 of the present invention; Figure 2 This is a metallographic diagram of the steel used in Comparative Example 1 of this invention; Figure 3 This is a metallographic diagram of the steel used in Comparative Example 2 of this invention; Figure 4 This is a metallographic diagram of the steel used in Comparative Example 3 of this invention.

[0074] from Figure 1It can be seen that the carbide inhomogeneity in the steel prepared in Example 1 is grade 1, with a particle size of less than 10 μm. The carbide inhomogeneity in the steel prepared in Comparative Example 1 is grade 2, with a particle size of approximately 20 μm. The carbide inhomogeneity in the steel prepared in Comparative Example 2 is grade 3, with a particle size of approximately 30 μm. The carbide inhomogeneity in the steel prepared in Comparative Example 3 is grade 1, with a particle size of approximately 20 μm.

[0075] 2. Hardness and toughness testing

[0076] Hardness and impact toughness tests were conducted on the steels from Examples 1-2 and Comparative Examples 1-3 (the standards for testing hardness and impact toughness were GB / T 230.1-2018 and GB / T229-2020), and the results are shown in Table 1.

[0077] Table 1

[0078]

[0079] As can be seen from Table 1, the steel in the embodiments of the present invention has significantly improved impact toughness compared with the comparative example. That is, the steel of the present invention has both wear resistance and high toughness, and can meet the working requirements of HRC62-64.

[0080] In addition, due to the significant advantages of the steel in Example 1 in terms of structure, strength, toughness, and wear resistance, the lifespan of tools and dies such as thread rolling wheels, silicon steel sheet stamping dies, and excavator bucket teeth made from this steel is 2-4 times longer than that of conventional steel (with a composition close to that of Comparative Example 2 steel).

Claims

1. A type of steel, characterized in that, The product, by mass fraction, contains the following components: Cr 4.8-10.2%, Mo 0.8-2.5%, V 1.5-3.5%, C 0.8-1.5%, Si 0.8-1.8%, Mn 0.3-0.8%, with the balance being Fe and unavoidable impurities. Its preparation method includes the following steps: (1) Steel smelting: Weigh the raw material components, mix them, and smelt them to obtain molten steel; (2) Spray forming: The molten steel is sprayed into a steel ingot; (3) Forging and heat treatment: The steel ingot is forged, then annealed, and after rough machining, it is subjected to quenching and tempering heat treatment and deep cryogenic treatment to obtain the steel; The steel, after quenching and tempering heat treatment, has a Rockwell hardness of HRC60-64. The transverse impact energy of a 10×10×55mm unnotched Charpy impact specimen with a hardness of HRC60-64 is 30-50J, and the longitudinal impact energy is 60-90J.

2. The steel according to claim 1, characterized in that, Based on mass fraction, it has the following components: Cr 5.0-10.0%, Mo 1.0-2.0%, V 1.5-3.0%, C 0.8-1.5%, Si 0.8-1.5%, Mn 0.3-0.8%, with the balance being Fe and unavoidable impurities.

3. The steel according to claim 1, characterized in that, The unavoidable impurities include P and / or S.

4. The steel according to claim 1, characterized in that, The mass fraction of the unavoidable impurities is less than or equal to 0.1%.

5. The steel according to claim 1, characterized in that, In step (1), the melting temperature is 1600-1650℃; and / or, in step (2), the process conditions during the spray forming process are: the flow rate of molten steel is 40-160 kg / min, the atomizing gas is nitrogen, the working pressure is 4-14 atm, and the molten steel is atomized into 5-150μm particles and sprayed at a speed of 100-300 m / s to form steel ingots.

6. The steel according to claim 1, characterized in that, In step (3), the starting temperature of the forging is 1100-1180℃, and the ending temperature of the forging is 800-880℃; and / or, the annealing process is as follows: hold at 840-890℃ for 3-5 hours, then cool to 700-780℃ at a cooling rate of 10-15℃ / h, hold for 2-4 hours, then furnace cool to 500-700℃ and finally air cool to a hardness ≤220HB.

7. A component, characterized in that, Includes the steel described in any one of claims 1-6.

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