Low-alloy martensite wear-resistant steel, preparation method and application

Abstract

The invention provides low-alloy martensite wear-resistant steel as well as a preparation method and application thereof, and the low-alloy martensite wear-resistant steel comprises the following chemical components in percentage by mass: 0.1 to 0.25 percent of C, 0.2 to 0.5 percent of Si, 1.2 to 1.6 percent of Mn, 0 to 0.02 percent of P, 0 to 0.002 percent of S, 0.05 to 0.25 percent of Cr, 0.01 to 0.3 percent of Ni, 0.2 to 0.5 percent of Mo, 0.0001 to 0.001 percent of La, 0.0001 to 0.001 percent of Ce and the balance of iron and other inevitable impurities. The Brinell hardness of the low-alloy martensitic wear-resistant steel ranges from 330 HBW to 390 HBW. The process method is simple, convenient to operate and suitable for large-scale production, the production cost and energy consumption are reduced, and the prepared low-alloy martensite wear-resistant steel remarkably prolongs the service life of parts in the manufacturing process of engineering mechanical parts.

Description

Technical Field

[0001] This invention belongs to the field of wear-resistant steel production technology, and particularly relates to a low-alloy martensitic wear-resistant steel, its preparation method, and its application. Background Technology

[0002] With the rapid development of science and technology and modern industry, the operating speed of mechanical equipment is increasing, and wear is one of the main failure modes of materials. Many workpieces and equipment fail rapidly due to wear. Millions of tons of steel are consumed annually due to abrasive wear, resulting in material waste and economic losses. The development of wear-resistant materials has become a crucial factor affecting modern production efficiency. Wear-resistant steel is widely used in various wear conditions, such as in excavators, bulldozers, mining machinery, roadbed equipment, and dump trucks. It plays a vital role in mitigating wear and tear on mechanical parts and extending product lifespan. Wear-resistant steel needs to have a high hardness value to ensure its resistance to friction and wear under harsh working conditions.

[0003] Currently, the main wear-resistant materials used are high-manganese steel, low-alloy cast iron, and low-alloy steel. Although these materials have certain wear resistance, they are prone to brittleness and insufficient toughness under specific working conditions, especially in low-temperature environments, which limits their application. There are few reports on low-alloy steels that simultaneously possess good strength, hardness, and wear resistance. Therefore, this invention proposes a low-alloy martensitic wear-resistant steel, its preparation method, and its applications. Summary of the Invention

[0004] The main objective of this invention is to provide a low-alloy martensitic wear-resistant steel, its preparation method, and its application, aiming to solve the technical problem of insufficient toughness and wear resistance of low-alloy wear-resistant steel under low-temperature conditions in the prior art.

[0005] To achieve the above objectives, the present invention provides a low-alloy martensitic wear-resistant steel, wherein the chemical composition of the low-alloy martensitic wear-resistant steel, by mass fraction, comprises: C 0.1-0.25%, Si 0.2-0.5%, Mn 1.2-1.6%, P 0-0.02%, S 0-0.002%, Cr 0.05-0.25%, Ni 0.01-0.3%, Mo 0.2-0.5%, La 0.0001-0.001%, Ce 0.0001-0.001%, with the remainder being iron and other unavoidable impurities.

[0006] The low-alloy martensitic wear-resistant steel has a Brinell hardness of 330–390 HBW.

[0007] According to the embodiments of this application, the low-alloy martensitic wear-resistant steel has an impact toughness ≥140J at a low temperature of -20℃; an impact toughness ≥120J at a low temperature of -40℃; and an impact toughness ≥80J at a low temperature of -60℃.

[0008] According to the embodiments of this application, the low-alloy martensitic wear-resistant steel has a yield strength of 900-1150 MPa, a tensile strength of 1000-1250 MPa, an elongation after fracture of 15-30%, and a low-temperature impact toughness of 140-170 J at -20℃.

[0009] According to an embodiment of this application, the precipitated phase of the low-alloy martensitic wear-resistant steel is carbide nanoparticles, and the particle size of the carbide nanoparticles is <60nm.

[0010] The present invention also provides a method for preparing the above-mentioned low-alloy martensitic wear-resistant steel, the steps of which include:

[0011] After desulfurization pretreatment of molten iron, converter smelting, LF+RH refining, addition of rare earth alloys to the tundish, and continuous casting, a cast billet is obtained.

[0012] The billet is rolled to obtain a steel coil; after heat treatment, the low-alloy martensitic wear-resistant steel is obtained.

[0013] The superheat of the intermediate ladle is 10–25°C.

[0014] The heat treatment includes: quenching and tempering the steel coil; the quenching temperature is 860-920℃, and the relationship between the quenching holding time t (minutes) and the thickness h (mm) of the steel plate is t = 1.4 × h + 15; the tempering temperature is 160-240℃, and the tempering holding time is 35-70 min.

[0015] According to the embodiments of this application, the holding time for quenching the single plate is 20 to 40 minutes; the cooling medium for quenching the single plate is water, and the temperature of the water is 10 to 50°C.

[0016] According to the embodiments of this application, the refining temperature is ≥1530℃ and the refining time is ≥45min.

[0017] The thickness of the billet is 170–230 mm, and the continuous casting speed is 0.9–1.2 m / min.

[0018] According to an embodiment of this application, the rolling process includes: heating the billet, rough rolling, finish rolling, and coiling to obtain the steel coil.

[0019] The billet is heated at a temperature of 1200–1230°C for 150–240 minutes.

[0020] The roughing temperature is 1100–1150℃, the finishing temperature is 880–940℃, and the coiling temperature is 550–620℃.

[0021] According to an embodiment of this application, the roughing includes 5 to 7 passes, with a single pass reduction rate of 10 to 15%.

[0022] The finishing rolling process includes 3 to 4 passes, with a single pass reduction rate of 5 to 8%.

[0023] Application of low-alloy martensitic wear-resistant steel prepared according to the above-mentioned method in the manufacture of engineering machinery parts.

[0024] The beneficial effects of this invention are:

[0025] The low-alloy martensitic wear-resistant steel of this invention utilizes the synergistic effect of low-alloy elements (such as Cr and Mn) and rare earth elements (such as La and Ce) in a specific process. During the quenching step, a martensitic matrix is ​​formed, and tempering promotes the precipitation of nanoscale carbides, resulting in a precipitation strengthening effect. This significantly refines the martensitic grain structure, improving both the material's strength and hardness while enhancing its toughness, achieving a balance between wear resistance and impact resistance. The addition of rare earth elements transforms harmful impurities in the steel, such as sulfur and oxygen, into stable sulfides and oxides, effectively reducing the number of inclusions and improving the steel's purity. The resulting low-alloy martensitic wear-resistant steel has a Brinell hardness of 330–390 HBW, and a stable hardened layer can form on the material surface to mitigate wear failure.

[0026] The above-mentioned process is simple and easy to operate, reducing production costs and energy consumption. It is suitable for large-scale production, and the low-alloy martensitic wear-resistant steel produced can significantly extend the service life of engineering machinery parts and reduce the frequency of equipment maintenance and replacement costs. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0028] Figure 1 This is a comparison chart of the impact energy of low-alloy martensitic wear-resistant steel (NM360PLUS) in Example 1 and ordinary wear-resistant steel (NM360) in Comparative Example 1 at different temperatures.

[0029] Figure 2 This is a SEM image of the low-alloy martensitic wear-resistant steel of Embodiment 1 of the present invention.

[0030] The realization of the objective, functional characteristics and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0033] To achieve the above objectives, the present invention provides a low-alloy martensitic wear-resistant steel, wherein the chemical composition of the low-alloy martensitic wear-resistant steel, by mass fraction, comprises: C 0.1-0.25%, Si 0.2-0.5%, Mn 1.2-1.6%, P 0-0.02%, S 0-0.002%, Cr 0.05-0.25%, Ni 0.01-0.3%, Mo 0.2-0.5%, La 0.0001-0.001%, Ce 0.0001-0.001%, with the remainder being iron and other unavoidable impurities.

[0034] The low-alloy martensitic wear-resistant steel has a Brinell hardness of 330–390 HBW.

[0035] In some embodiments, carbon dissolves in austenite, forming high-hardness lath martensite after quenching. Due to its finer substructure and higher proportion of retained austenite, it enhances the ability to absorb impact energy. The introduction of carbon improves the wear resistance of steel. Silicon acts as a deoxidizer, deoxidizing during smelting, reducing oxide inclusions in the steel, inhibiting cementite precipitation, and improving the steel's strength and tempering stability. The introduction of manganese promotes the transformation of austenite to full martensite and refines the grain size. The introduction of chromium generates chromium oxide, which acts as a passivation layer, enhancing the steel's wear resistance and oxidation resistance. Nickel, in combination with Mo and Cr, improves low-temperature impact toughness. Molybdenum can form Mo2C carbides with carbon, enhancing the steel's wear resistance and inhibiting the segregation of impurities such as phosphorus at grain boundaries, improving tempering brittleness. The introduction of rare earth elements lanthanum and cerium effectively removes harmful impurities such as sulfur and oxygen from steel by forming stable sulfides and oxides, thus reducing the number of inclusions. This not only improves the purity of the steel but also optimizes its internal structure, thereby enhancing the overall performance of the material. Simultaneously, the introduction of rare earth elements can transform inclusions such as MnS into rare earth sulfur oxides, reducing stress concentration. It also promotes the formation of crystal nuclei in the steel, slowing down grain growth and refining the grain size, thereby enhancing the strength and toughness of the steel. Through optimization of the composition and content of different elements, the resulting low-alloy martensitic wear-resistant steel has a Brinell hardness of 330–390 HBW.

[0036] The aforementioned low-alloy martensitic wear-resistant steel, through the synergistic effect of low-alloy elements (such as Cr and Mn) and rare earth elements (such as La and Ce), combined with advanced processing techniques, promotes the precipitation of nanoscale carbides, resulting in a precipitation strengthening effect. This significantly refines the martensitic grain structure, improving both the material's strength and hardness while enhancing its toughness, achieving a balance between wear resistance and impact resistance. The addition of rare earth elements transforms harmful impurities in the steel, such as sulfur and oxygen, into stable sulfides and oxides, effectively reducing the number of inclusions and increasing the steel's purity. The resulting low-alloy martensitic wear-resistant steel has a Brinell hardness of 330–390 HBW, and a stable hardened layer can form on the material surface to mitigate wear failure.

[0037] In some embodiments, the low-alloy martensitic wear-resistant steel has an impact toughness ≥140J at a low temperature of -20℃; an impact toughness ≥120J at a low temperature of -40℃; and an impact toughness ≥80J at a low temperature of -60℃.

[0038] In some specific embodiments, the low-alloy martensitic wear-resistant steel exhibits an impact toughness of 161 J at -20°C, 128 J at -40°C, and 102 J at -60°C. This low-temperature impact toughness demonstrates the excellent resistance to low-temperature brittleness and adaptability to extreme environments inherent in this low-alloy martensitic wear-resistant steel.

[0039] In some embodiments, the low-alloy martensitic wear-resistant steel has a yield strength of 900–1150 MPa, a tensile strength of 1000–1250 MPa, an elongation after fracture of 15–30%, and a low-temperature impact toughness of 140–170 J at -20°C.

[0040] In some embodiments, the low-alloy martensitic wear-resistant steel has a yield strength of 950–1150 MPa, a tensile strength of 1100–1250 MPa, and an elongation after fracture of 15–30%.

[0041] In some embodiments, the precipitated phase of the low-alloy martensitic wear-resistant steel is carbide nanoparticles, and the particle size of the carbide nanoparticles is <60nm.

[0042] In some embodiments, the microstructure of the low-alloy martensitic wear-resistant steel is nanoscale martensite, with nanoscale precipitates and high-density dislocation clusters distributed within the martensite laths, and carbide nanoparticles including (V... x Ti y C(x+y=1), VC, TiC, M 2.5 C and M3C (M represents Fe, Mn and Cr elements) form a precipitation enhancement effect, and the particle size of the carbide nanoparticles is <60nm.

[0043] The present invention also provides a method for preparing the above-mentioned low-alloy martensitic wear-resistant steel, the steps of which include:

[0044] After desulfurization pretreatment of molten iron, converter smelting, LF+RH refining, addition of rare earth alloys to the tundish, and continuous casting, a cast billet is obtained.

[0045] The billet is rolled to obtain a steel coil; after heat treatment, the low-alloy martensitic wear-resistant steel is obtained.

[0046] The superheat of the intermediate ladle is 10–25°C.

[0047] The heat treatment includes: quenching and tempering the steel coil; the quenching temperature is 860-920℃, and the relationship between the quenching holding time t (minutes) and the thickness h (mm) of the steel plate is t = 1.4 × h + 15; the tempering temperature is 160-240℃, and the tempering holding time is 35-70 min.

[0048] In some implementations, the steel coil is further cut into individual steel sheets, followed by single-sheet quenching and single-sheet tempering.

[0049] In some embodiments, molten iron containing the same chemical composition as low-alloy martensitic wear-resistant steel undergoes desulfurization pretreatment, converter smelting, LF+RH refining, rare earth alloy addition in the tundish, and continuous casting to obtain a billet. The refining temperature is controlled at ≥1530℃, and the refining time at ≥45min. The superheat of the tundish is controlled at 10–25℃, and 70–100 kg of rare earth alloy is added to the tundish. This alloy reacts with impurities such as oxygen and sulfur in the steel to form rare earth compounds with high melting points, thereby reducing inclusions and improving the purity of the steel. Simultaneously, the addition of rare earth elements also improves the steel's oxidation resistance, corrosion resistance, and crack resistance. By controlling the continuous casting speed to 0.9–1.2 m / min, a billet with a thickness of 170–230 mm is obtained.

[0050] In some embodiments, the billet is rolled, which includes heating, rough rolling, finish rolling, and coiling to obtain the steel coil, thereby making the internal structure of the material more uniform and eliminating segregation and inhomogeneity in the billet. The billet is heated at a temperature of 1200–1230°C for a duration of 150–240 minutes.

[0051] The roughing temperature is 1100–1150℃, the finishing temperature is 880–940℃, and the coiling temperature is 550–620℃.

[0052] In some embodiments, the heating time of the billet is 150 to 200 minutes.

[0053] In some implementations, the finishing rolling speed is 6.0 to 10.0 m / s, such as 6.8 m / s, to match the rolling speed with the temperature and prevent excessive cooling, which would affect the stability of the rolling force and the mechanical properties of the steel.

[0054] In some implementations, the surface quality of steel coils can be improved by controlling appropriate rolling temperatures. For example, controlling the billet heating temperature can suppress excessive iron oxide scale formation and reduce surface wear. The rough rolling process can refine grains, improving the quality of intermediate billets and rolling efficiency. Controlling the finish rolling temperature can reduce uneven distribution of thermal stress during rolling, avoiding shape defects such as warping and waviness. The coiling temperature can suppress residual stress and maintain the stability of the martensitic structure. A suitable coiling temperature can reduce interlayer oxidative adhesion and surface color difference in steel coils. Through the coordination of the above process parameters, the low-alloy martensitic wear-resistant steel is obtained.

[0055] In some embodiments, the roughing includes 5 to 7 passes, with a single pass reduction of 10 to 15%.

[0056] The finishing rolling process includes 3 to 4 passes, with a single pass reduction rate of 5 to 8%.

[0057] In some implementations, the roughing process employs multi-pass rolling to significantly thin the billet, and controlling the reduction rate per pass can disperse deformation stress, preventing defects such as edge cracks and central porosity. It can also balance efficiency and safety to gradually refine the grain size. Finishing rolling is typically used to gradually thin to the target thickness, allowing for precise dimensional control. Multi-pass rolling combined with a rolling temperature gradient can promote dynamic recrystallization, refine the grain size, and improve the strength and toughness of the steel.

[0058] In some implementations, to obtain high-performance low-alloy martensitic wear-resistant steel, steel coils are typically cut into individual steel sheets, which are then quenched and tempered individually. The quenching and tempering temperatures are controlled to ensure that the resulting low-alloy martensitic wear-resistant steel has stable and uniform properties.

[0059] In some implementations, after the steel coil is slowly cooled to room temperature in a slow cooling box, it is cut into single-layer steel sheets according to different size requirements.

[0060] In some implementations, a heating furnace is used to heat the single steel sheet. After the temperature of the heating furnace stabilizes at the quenching temperature of the single sheet (860–920°C), the single sheet is placed in the heating furnace for heating and holding at that temperature to ensure complete austenitization. For example, if the thickness of the single sheet is 10 mm, the holding time is 29 minutes.

[0061] In some embodiments, the holding time for quenching the single plate is 20 to 40 minutes; the cooling medium for quenching the single plate is water, and the temperature of the water is 10 to 50°C.

[0062] In some implementations, the veneer is cooled with water after being removed from the furnace. The water temperature is 15–35°C, and the veneer is quenched and cooled to the same temperature as the water. Rapid cooling prevents the austenite from transforming into other phases, such as pearlite or ferrite, thereby obtaining martensite.

[0063] In some embodiments, the tempering temperature of the single veneer is 170–190°C, and the holding time for tempering is 35–70 minutes. After tempering, the single veneer is air-cooled to room temperature to obtain the low-alloy martensitic wear-resistant steel.

[0064] In some implementations, after tempering, the single board is slowly cooled on a cooling bed until it reaches room temperature, after which it is packaged and printed.

[0065] The above-mentioned process is simple, easy to operate, reduces production costs and energy consumption, and is suitable for large-scale production.

[0066] The application of the low-alloy martensitic wear-resistant steel prepared by the above-mentioned method in the manufacturing of engineering machinery parts can significantly extend the service life of the parts and reduce the frequency of equipment maintenance and replacement costs.

[0067] To further illustrate the present invention, the following examples are provided:

[0068] Example 1

[0069] An embodiment of the present invention provides a low-alloy martensitic wear-resistant steel, the chemical composition of which is shown in Table 1. The preparation steps include: pre-treatment of molten iron by desulfurization, smelting in a converter, refining with LF+RH, adding rare earth alloys to the tundish and continuous casting to obtain a billet; the billet is rolled to obtain a steel coil; and then heat-treated to obtain the final product.

[0070] The superheat of the tundish was 15℃, and 100kg of rare earth alloy was added to the tundish. A converter plant produced 200t of molten steel according to the chemical composition in Table 1, which was then continuously cast. The casting speed was 1.1m / min, and the billet thickness was 230mm. The billet was heated to 1200℃ and held for 210min before being removed from the furnace. It then underwent rough rolling, finish rolling, and coiling. The billet underwent 7 passes of rough rolling at 1125℃, finish rolling at 920℃, and coiling at 580℃, resulting in steel coils.

[0071] After receiving steel coils cooled to room temperature, the cross-cutting line of a heat treatment plant flattens the steel plates according to requirements and cuts them into individual sheets according to dimensions. Then, each sheet undergoes single-sheet quenching and tempering. The quenching temperature is 900℃, and the holding time is 30 minutes. The tempering temperature is 220℃, and the holding time is 40 minutes. After slow cooling to room temperature, the sheets are packaged and printed.

[0072] Tests showed that the low-alloy martensitic wear-resistant steel has a yield strength of 959 MPa, a tensile strength of 1146 MPa, an elongation after fracture of 22.6%, a Brinell hardness of 368 HBW, a low-temperature impact toughness of 161 J at -20℃, a low-temperature impact toughness of 128 J at -40℃, and a low-temperature impact toughness of 102 J at -60℃.

[0073] Comparative Example 1

[0074] A common wear-resistant steel is provided, the chemical composition of which is shown in Table 2. The preparation steps include: desulfurizing and pretreating molten iron, smelting in a converter, refining with LF+RH and continuous casting to obtain a billet. The billet is then rolled to obtain a steel coil, which is then heat-treated to obtain the final product.

[0075] A converter plant produced 200 tons of molten steel according to the chemical composition in Table 1, which was then continuously cast at a casting speed of 0.9 m / min. The billet was heated to 1220℃ and held at that temperature, followed by rough rolling, finish rolling, and cooling. The rough rolling temperature was 830℃, and the finish rolling temperature was 700℃. The billet was then stacked for slow cooling and subjected to heat treatment processes of quenching and low-temperature tempering. The quenching temperature was 875℃, and the quenching holding time was 65 min. The tempering temperature was 190℃, and the tempering holding time was 100 min. After tempering, the billet was stacked for slow cooling to room temperature to obtain ordinary wear-resistant steel.

[0076] Tests show that the yield strength of ordinary wear-resistant steel is 850 MPa, the tensile strength is 1020 MPa, the elongation after fracture is 15%, the Brinell hardness is 360 HBW, the impact toughness at -20℃ is 95 J, the impact toughness at -40℃ is 81 J, and the impact toughness at -60℃ is 69 J.

[0077] Table 1. Chemical composition (wt%) of low-alloy martensitic wear-resistant steel and ordinary wear-resistant steel

[0078] element C Si Mn P S Cr Ni Mo La Ce B Ti Example 1 0.16 0.50 1.50 0.009 0.001 0.25 0.08 0.25 0.006 0.007 - - Comparative Example 1 0.13 0.25 1.30 ≤0.02 ≤0.005 0.42 0.30 0.10 - - 0.0006 0.012

[0079] Table 1 shows the chemical composition of low-alloy martensitic wear-resistant steel and ordinary wear-resistant steel. Figure 1 This is a comparison chart of the impact energy of low-alloy martensitic wear-resistant steel (NM360PLUS) in Example 1 and ordinary wear-resistant steel (NM360) in Comparative Example 1 at different temperatures. Figure 2 This is a SEM image of the low-alloy martensitic wear-resistant steel of Embodiment 1 of the present invention. From... Figure 1 As can be seen, through the synergistic effect of low-alloy elements (such as Cr and Mn) and rare earth elements (such as La and Ce), and in conjunction with the processing technology, the low-alloy martensitic wear-resistant steel prepared has a yield strength of 900–1150 MPa, a tensile strength of 1000–1250 MPa, an elongation after fracture of 15–30%, and a Brinell hardness of 330–390 HBW. It exhibits excellent impact toughness at low temperatures. Ordinary wear-resistant steel has an impact toughness of 69 J at -60℃, while the low-alloy martensitic wear-resistant steel of this invention has an impact toughness of 102 J at -60℃, maintaining high impact toughness even at low temperatures, and possessing high impact resistance and wear resistance.

[0080] Figure 2 As can be seen, the low-alloy martensitic wear-resistant steel of the present invention has a uniform morphology. The process of the present invention is simple and easy to operate, reducing production costs and energy consumption, and is suitable for large-scale production. Furthermore, the application of the low-alloy martensitic wear-resistant steel prepared according to the above-mentioned method in the manufacture of engineering machinery components can significantly extend the service life of components and reduce equipment maintenance frequency and replacement costs.

[0081] In summary, the above-described technical solutions of the present invention are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention's specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A low-alloy martensitic wear-resistant steel, characterized in that, The chemical composition of the low-alloy martensitic wear-resistant steel, by mass fraction, includes: C 0.1-0.25%, Si 0.2-0.5%, Mn 1.2-1.6%, P 0-0.02%, S 0-0.002%, Cr 0.05-0.25%, Ni 0.01-0.3%, Mo 0.2-0.5%, La 0.0001-0.001%, Ce 0.0001-0.001%, with the remainder being iron and other unavoidable impurities; The low-alloy martensitic wear-resistant steel has a Brinell hardness of 330–390 HBW.

2. The low-alloy martensitic wear-resistant steel according to claim 1, characterized in that, The low-alloy martensitic wear-resistant steel has an impact toughness ≥140J at -20℃, ≥120J at -40℃, and ≥80J at -60℃.

3. The low-alloy martensitic wear-resistant steel according to claim 1, characterized in that, The low-alloy martensitic wear-resistant steel has a yield strength of 900–1150 MPa, a tensile strength of 1000–1250 MPa, an elongation after fracture of 15–30%, and a low-temperature impact toughness of 140–170 J at -20℃.

4. The low-alloy martensitic wear-resistant steel according to claim 1, characterized in that, The precipitated phase of the low-alloy martensitic wear-resistant steel is carbide nanoparticles, and the particle size of the carbide nanoparticles is <60nm.

5. A method for preparing low-alloy martensitic wear-resistant steel as described in any one of claims 1 to 4, characterized in that, step... include: After desulfurization pretreatment of molten iron, converter smelting, LF+RH refining, addition of rare earth alloys to the tundish and continuous casting, a billet is obtained. The billet is rolled to obtain a steel coil; After further heat treatment, the low-alloy martensitic wear-resistant steel is obtained. The superheat of the intermediate ladle is 10–25°C; The heat treatment includes: quenching and tempering the steel coil; the quenching temperature is 860-920℃, and the relationship between the quenching holding time t (minutes) and the thickness h (mm) of the steel plate is t = 1.4 × h + 15; the tempering temperature is 160-240℃, and the tempering holding time is 35-70 min.

6. The method for preparing low-alloy martensitic wear-resistant steel according to claim 5, characterized in that, The quenching holding time is 20-40 minutes; the quenching cooling medium is water, and the water temperature is 10-50℃.

7. The method for preparing low-alloy martensitic wear-resistant steel according to claim 5, characterized in that, The refining temperature is ≥1530℃ and the refining time is ≥45min; The thickness of the billet is 170–230 mm, and the continuous casting speed is 0.9–1.2 m / min.

8. The method for preparing low-alloy martensitic wear-resistant steel according to claim 5, characterized in that, The rolling process includes: heating the billet, rough rolling, finish rolling and coiling to obtain the steel coil; The temperature for heating the billet is 1200–1230°C, and the heating time is 150–240 min. The roughing temperature is 1100–1150℃, the finishing temperature is 880–940℃, and the coiling temperature is 550–620℃.

9. The method for preparing low-alloy martensitic wear-resistant steel according to claim 8, characterized in that, The roughing process includes 5 to 7 passes, with a single pass reduction of 10 to 15%. The finishing rolling process includes 3 to 4 passes, with a single pass reduction rate of 5 to 8%.

10. The application of the low-alloy martensitic wear-resistant steel according to any one of claims 1 to 4 or the low-alloy martensitic wear-resistant steel prepared by the preparation method according to any one of claims 5 to 9 in the manufacture of engineering machinery parts.

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