Wear-resistant steel and method for producing same

Abstract

The application discloses a wear-resistant steel and a preparation method thereof. The preparation method of the wear-resistant steel comprises the following steps: pouring molten steel into a thin slab by using a thin slab continuous casting machine; heating the thin slab to a preset temperature by using a heating furnace, and then removing the furnace-born iron scale by using a finishing rolling descaling machine; and rolling the descaled thin slab by using a multi-stand hot continuous rolling mill group, wherein the first-stand pass reduction rate is not less than 60%, the finish rolling temperature is 825-880 DEG C, and a steel strip with a target thickness is obtained; then, the steel strip is subjected to laminar cooling at a cooling speed of 30-80 DEG C / s, and then the steel strip is naturally cooled to room temperature, so that the wear-resistant steel is obtained. According to the embodiment of the application, the wear-resistant steel meeting the requirements of high wear resistance and high toughness can be continuously and low-cost produced.

Description

Technical Field

[0001] This application belongs to the field of metallic materials and relates to a wear-resistant steel and its preparation method. Background Technology

[0002] Low-alloy high-strength wear-resistant steel is mainly used in engineering machinery and equipment, as well as special vehicles, in mining, railway, and coal industries. For mining trucks and mechanical wear-resistant parts (such as: large autogenous mill liners, coal mining machine buckets, chisels, tooth plates, etc.), wear-resistant steel needs to meet extremely high wear resistance and excellent toughness when used.

[0003] However, existing wear-resistant steels cannot simultaneously satisfy both high wear resistance and excellent toughness. Summary of the Invention

[0004] This application provides a wear-resistant steel and its preparation method, which enables continuous and low-cost production of wear-resistant steel that simultaneously meets the requirements of high wear resistance and high toughness.

[0005] In a first aspect, embodiments of this application provide a method for preparing wear-resistant steel, comprising:

[0006] Molten steel is cast into thin slabs using a thin slab continuous casting machine. These slabs contain austenitic grains. The slabs are then heated to a preset temperature in a furnace and descaled using a descaling machine to remove the furnace-grown iron oxide scale. A multi-stand hot rolling mill is used to roll the scaled slabs, with a reduction rate of at least 60% on the first stand and a final rolling temperature of 825–880℃, yielding a steel strip of the target thickness. Laminar flow cooling is employed at a rate of 30–80℃ / s to cool the strip to 300–340℃, followed by natural cooling to room temperature to obtain wear-resistant steel. By weight percentage, the wear-resistant steel comprises: C 0.62%–0.75%, Si 1.8%–2.2%, Mn 0.8%–1.2%, Cr 0.8%–1.2%, Cu 0.4%–0.8%, Ni 0.9%–1.1%, Al 0.015%–0.05%, P ≤0.01%, S ≤0.01%, N ≤0.005%, Nb 0.01%–0.05%, V 0.05%–0.35%, with the remainder being Fe and unavoidable impurities.

[0007] In any embodiment of this application, during the laminar flow cooling step, the austenite grains in the steel strip are transformed into lower bainite. At the same time, the Cr element dissolved in the austenite grains improves the hardenability of the intermediate slab and promotes the formation of lower bainite and martensite.

[0008] In any embodiment of this application, the Nb and V elements added to the wear-resistant steel form microalloyed carbonitrides with C and N, respectively, which hinder the growth of austenite grains and refine the austenite grains, thereby improving the toughness of the wear-resistant steel while increasing its strength.

[0009] In any embodiment of this application, in the step of casting molten steel into thin slabs using a thin slab continuous casting machine, the thickness of the thin slab is 55-65 mm.

[0010] In any embodiment of this application, in the step of heating the thin slab to a preset temperature using a heating furnace, the preset temperature is 1250-1300°C.

[0011] In any embodiment of this application, the wear-resistant steel comprises, by weight percentage: C 0.62%–0.75%, Si 1.8%–2.2%, Mn 0.8%–1.2%, Cr 0.8%–1.2%, Cu 0.4%–0.8%, Ni 0.9%–1.1%, Al 0.021%–0.037%, P ≤0.01%, S ≤0.01%, N ≤0.005%, Nb 0.011%–0.029%, V 0.063%–0.081%, with the remainder being Fe and unavoidable impurities.

[0012] Secondly, this application provides a wear-resistant steel, which is obtained by the above-described preparation method.

[0013] In any embodiment of this application, the thickness of the wear-resistant steel is 2 to 8 mm.

[0014] In any embodiment of this application, the wear-resistant steel has a Brinell hardness ≥450HBW and a room temperature impact energy ≥47J.

[0015] In any embodiment of this application, the wear-resistant steel contains bainite and martensite, wherein the lower bainite accounts for 90% to 95% and the martensite accounts for 5% to 10%.

[0016] The wear-resistant steel and its preparation method in this application embodiment, by compounding Nb and V elements and controlling the Cr, Cu, Ni and other elements in the composition, and then using a CSP production line for production, can not only ensure the wear resistance and toughness of the wear-resistant steel while ensuring the strength level, but also reduce the repeated heating, uncoiling and bending of the plate coil in the production process, and can also eliminate the cold rolling and annealing heat treatment processes, thereby further reducing the production cost. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 The typical metallographic structure of the wear-resistant steel plate prepared in Examples 1 and 5 of this application is shown. Detailed Implementation

[0019] To better understand the above-mentioned objectives, features, and advantages of this application, the solution of this application will be further described below. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0020] Numerous specific details are set forth in the following description in order to provide a full understanding of this disclosure, but this application may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only some embodiments of this application, and not all embodiments.

[0021] The following detailed description, with appropriate reference to the accompanying drawings, discloses an embodiment of a wear-resistant steel and its preparation method according to this application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided for the purpose of enabling those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0022] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60–120 and 80–110 are listed for a specific parameter, it is understood that ranges of 60–110 and 80–120 are also expected. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1–3, 1–4, 1–5, 2–3, 2–4, and 2–5. In this application, unless otherwise stated, the numerical range "a–b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0023] Unless otherwise specified, all embodiments and optional embodiments of this application may be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of this application.

[0024] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions, and such technical solutions shall be deemed to be included in the disclosure of this application.

[0025] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0026] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0027] Unless otherwise specified, this application uses conventional testing methods or testing methods recommended by the instrument.

[0028] CN107217202A discloses a wear-resistant steel with a Brinell hardness of 400 and its manufacturing method. The chemical composition of the steel, by mass percentage, is: C 0.25-0.28%, Si 0.22-0.28%, Mn 1.15-1.24%, P≤0.01%, S≤0.005%, Cr 0.2-0.25%, Cu 0.01-0.015%, Al 0.03-0.05%, Ni 0.04-0.045%, Mo 0.01-0.02%, Ti 0.03-0.04%, V 0.007-0.018%, B≤0.004%, with the remainder being iron and unavoidable impurities. The invention yields a tempered martensitic structure, and the wear-resistant steel has a tensile strength of 1730-1800 MPa, an elongation ≥9%, and an impact energy exceeding 25 J at -20℃. The material prepared by this invention has high wear resistance, but poor toughness and insufficient overall performance.

[0029] CN109055857A discloses an HB500 grade martensitic wear-resistant steel for shovel blades and its processing method. The steel's composition by mass percentage includes: C 0.30–0.40%, Si 0.25–0.50%, Mn 0.30–0.80%, P ≤0.015%, S ≤0.010%, Cr 0.65–1.15%, Mo 0.55–0.85%, Ti 0.12–0.20%, B 0.002–0.006%, Als 0.02–0.05%, with the remainder being Fe and trace impurities. The tempered martensitic structure obtained by this invention has a steel plate thickness range of 20–40 mm, a tensile strength ≥1600 MPa, an elongation ≥9%, and HBW / 10 / 3000 ≥500. The material prepared by this invention has high wear resistance, but poor toughness and insufficient overall performance.

[0030] CN116904871A discloses an HB400 grade high-toughness wear-resistant steel and its production method. The components and their mass percentages include: C: 0.10–0.18%, Mn: 0.2–1.3%, P ≤0.020%, S ≤0.010%, Als: 0.03–0.06%, Nb: 0.010–0.02%, Ti: 0.005–0.02%, Si: ≤0.020% or B: ≤0.003%, or a combination of both in any proportion, with the remainder being Fe and trace impurities. The steel obtained by this invention exhibits a fine tempered martensitic structure. Under the premise that the product hardness HB is not less than 400, yield strength not less than 930 MPa, tensile strength not less than 1100 MPa, elongation not less than 10%, and impact energy at 40℃ not less than 50 J, the material prepared by this invention has high toughness, but its wear resistance is poor and its overall performance is insufficient.

[0031] CN113881894A discloses a method for preparing a precipitate-reinforced bainitic-martensitic multiphase wear-resistant liner. By adding carbide-forming elements and controlling the heat treatment process, a large number of micron-sized precipitates are precipitated in the multiphase steel, thereby improving the wear resistance of the material without increasing the carbon content. The final multiphase steel liner has a hardness of HBW426-445 and an impact toughness of 25-35J. While the material prepared by this invention has high wear resistance, its toughness is poor and its overall performance is insufficient.

[0032] CN116875876A discloses a bainitic / martensitic multiphase wear-resistant steel and its heat treatment method. The components and their mass percentages are as follows: C: 0.4–0.9%, Si: 1.3–2.5%, Mn: 0.7–2.4%, Cr: 0.5–1.4%, Al: 0.8–2.5%, S≤0.01%, P≤0.01%, with the remainder being Fe and unavoidable impurities. The preparation method includes ingot preparation, forging into billets, spheroidizing annealing, austenitizing, and isothermal quenching. The prepared high-strength, high-toughness, and wear-resistant steel has a nano-bainitic microstructure, a minimum tensile strength of 1873 MPa, a minimum elongation of 12.4%, a minimum Brinell hardness of 607 HBW, and a minimum room-temperature impact toughness of 40 J / cm². 2 The patent has a high Al content, which causes problems such as transverse depressions, cracks, and billet breakage in the continuously cast slab. It can only be used for ingot production and is difficult to realize continuous multi-furnace casting production in hot rolling production lines, resulting in low efficiency and high cost.

[0033] In summary, existing wear-resistant steels mainly rely on martensitic strengthening to ensure wear resistance, but their toughness is poor after low-temperature tempering, making it difficult to simultaneously achieve high wear resistance and high toughness. Furthermore, wear-resistant steels containing bainite-martensite structure struggle to balance toughness with continuous production. Therefore, there is an urgent need to research a wear-resistant steel with excellent comprehensive properties—high wear resistance, high toughness, and ease of continuous, low-cost manufacturing.

[0034]

Preparation Method

[0035] A method for preparing wear-resistant steel includes: S1. Casting molten steel into thin slabs using a thin slab continuous casting machine, the thin slabs containing austenitic grains; S2. Heating the thin slabs to a preset temperature using a heating furnace, and then descaling them using a descaling machine to obtain thin slabs with removed furnace-grown iron oxide scale; S3. Rolling the thin slabs with removed furnace-grown iron oxide scale using a multi-stand hot continuous rolling mill, wherein the reduction rate of the first stand pass is not less than 60%, and the final rolling temperature is 825-880℃, to obtain a steel strip of the target thickness; S4. Cooling the steel strip to 300-340℃ using laminar flow cooling at a cooling rate of 30-80℃ / s, and then naturally cooling to room temperature to obtain wear-resistant steel; S5. By weight percentage, the wear-resistant steel includes: C 0.62%-0.75%, Si 1.8%-2.2%, Mn 0.8%-1.2%, Cr The composition is as follows: 0.8%–1.2% Cu, 0.4%–0.8% Ni, 0.9%–1.1% Al, 0.015%–0.05% P≤0.01%, S≤0.01%, N≤0.005%, Nb 0.01%–0.05%, V 0.05%–0.35%, with the remainder being Fe and unavoidable impurities. In step S1, the prepared molten steel, after refining, is poured into the crystallizer through the pouring head of a thin slab continuous casting machine. The cooling water in the crystallizer then rapidly cools the molten steel, causing it to solidify. After continuous casting, the first slab is obtained. During this process, carbon dissolves in the interstitial solid solution in α-Fe to form ferrite. The ferrite then transforms into austenite at 912℃ to 1394℃, changing from a body-centered cubic structure to a face-centered cubic structure. In step S2, a heating furnace is used to maintain the temperature of the thin slab to facilitate surface treatment processes such as descaling, thereby improving the surface quality of the wear-resistant steel. In step S3, a multi-stand hot continuous rolling mill is used to perform roughing and finishing rolling on the surface-treated slab. The reduction rate of the first stand pass is not less than 60%, which can effectively roll the continuously cast slab with a thickness of 55-65mm into a thickness of 20-25mm. In addition, the larger reduction rate can transform the coarse austenite structure in the first slab into a flat austenite structure, and then transform it into a fine austenite structure through subsequent heating and recrystallization, thus refining the austenite grain size. The finishing rolling temperature is 825–880℃ because the deformation termination temperature has a significant impact on the microstructure and properties of steel. A higher deformation termination temperature leads to a stronger tendency for grain agglomeration and growth, resulting in coarser austenite grains and lower strength. To ensure the slab is rolled within a uniform austenite region to obtain a uniform microstructure and good properties, the finishing rolling temperature must be controlled above the ferrite transformation initiation temperature. In step S4, after laminar cooling, the steel coil is placed in air and allowed to cool naturally to room temperature. In this wear-resistant steel, carbon (C) is a fundamental element and the most economical and effective strengthening element. A lower carbon content design results in decreased strength after hot stamping; however, an excessively high carbon content reduces the steel's plasticity and is detrimental to weldability.Therefore, considering both economic efficiency and overall performance, the carbon content is controlled between 0.62% and 0.75%. Silicon is the most basic element in steel and also one of the most important elements in the wear-resistant steel of this application. Si can inhibit the precipitation of cementite within a certain temperature range, but its inhibitory effect on ε-carbides is relatively limited. Si inhibits cementite precipitation, allowing carbon atoms to diffuse from martensite into the retained austenite, thereby stabilizing the retained austenite. The Si content is generally not less than 1.8%, otherwise it cannot inhibit cementite precipitation; the Si content should also generally not exceed 2.2%, otherwise hot cracking is likely to occur during steel plate welding, causing difficulties in the application of the steel plate. Therefore, the Si content is controlled within the range of 1.8% to 2.2%. Mn has a solid solution strengthening effect and is one of the important elements for improving material strength; however, excessive manganese content can be detrimental to weldability. Therefore, the upper limit of manganese is set at 1.20%, and the manganese content added to the wear-resistant steel of this application is 0.8% to 1.2%. Cr is an important element for improving the hardenability of steel. It dissolves into austenite, increasing its stability and contributing to the formation of bainitic microstructure. Simultaneously, chromium improves the tempering stability of steel. However, its effect on improving hardenability becomes excessive when the chromium content exceeds 1.2%. In this application, the chromium content is controlled between 0.8% and 1.2%. Cu's prominent role in steel is improving the atmospheric corrosion resistance of ordinary low-alloy steel, especially when used in combination with phosphorus. Adding copper also increases the strength and yield ratio of steel without adversely affecting weldability. At low copper content, its effect is similar to that of nickel, but weaker; at higher content, it is detrimental to hot deformation processing, leading to copper embrittlement during hot deformation. In this application, the copper content is controlled between 0.4% and 0.8%. Ni can significantly improve the strength of steel while maintaining extremely high toughness. Nickel is a precious metal; considering both cost and performance, the nickel content is controlled between 0.9% and 1.1%. Als is added for deoxidation; its effect is negligible when the Al content is less than 0.015%. On the other hand, adding excessive amounts of aluminum easily forms alumina agglomerates, so the aluminum content is controlled within the range of 0.015% to 0.050%. P is a harmful element in steel, easily causing segregation at the center of the cast billet. During subsequent hot rolling, it tends to agglomerate at grain boundaries, significantly increasing the steel's brittleness. Considering cost and without affecting steel performance, its content is controlled below 0.01%. S is a very harmful element; sulfur in steel often exists as manganese sulfides. These sulfide inclusions deteriorate the steel's toughness and cause anisotropy in its properties. Therefore, the sulfur content in steel should be controlled as low as possible. Considering manufacturing costs, the sulfur content in steel is controlled below 0.01%. Nitrogen (N) can increase the strength of steel; however, nitrogen has a strong affinity for niobium and vanadium, which can form large niobium nitride and vanadium nitride particles in steel at high temperatures, severely impairing the plasticity and toughness of the steel. In addition, a higher nitrogen content will increase the amount of microalloying elements required to stabilize nitrogen, thereby increasing costs.Therefore, the nitrogen content should be minimized; in this application, nitrogen is controlled below 0.005%. Niobium (Nb) is a carbon and nitrogen strengthening element. Adding a small amount of niobium to steel can form a certain amount of niobium carbides and nitrides, thereby hindering austenite grain growth and refining the austenite grains. This achieves ultra-high strength while improving the steel's ductility and toughness. However, excessive niobium will combine with carbon to form coarse carbonitrides, thus reducing the material's hardness and strength. Simultaneously, the nanoscale precipitates of Nb can act as hydrogen traps, preventing hydrogen embrittlement. Therefore, its total content is controlled to not exceed 0.05%. V can improve the hardenability of steel, dissolve in ferrite to have a strengthening effect, form stable carbides, and refine grains. N can enhance the effect of V. Simultaneously, the nanoscale precipitates of V can also act as hydrogen traps, preventing hydrogen embrittlement. Therefore, V is controlled to not exceed 0.35%.

[0036] In some embodiments, the heating furnace in step S2 may be a tunnel-type roller hearth furnace.

[0037] In some embodiments, the multi-stand hot rolling mill in step S3 can be a 7-stand hot rolling mill with vertical rolls.

[0038] In some embodiments, during the laminar flow cooling step, the austenite grains in the steel strip transform into lower bainite. Simultaneously, the Cr element dissolved in the austenite grains improves the hardenability of the intermediate slab, thereby obtaining a small amount of martensite. Within this temperature range, the formation of brittle upper bainite can be avoided, resulting in a lower bainite structure with excellent toughness, ensuring good toughness and plasticity. Austenite is a lamellar microstructure of steel, typically a non-magnetic solid solution of a small amount of carbon dissolved in γ-Fe, also known as woestenite or γ-Fe. In step S1, the interstitial solid solution of carbon dissolved in α-Fe forms ferrite, which then transforms into austenite at temperatures between 912°C and 1394°C.

[0039] In some embodiments, laminar cooling in step S4 can be performed using UFC+TMCP. Ultra-Fast Cooling (UFC) is a new technology developed internationally in recent years for controlling the cooling of strip steel. Controlled rolling and controlled cooling technology, namely TMCP technology, is one of the greatest achievements of the 20th-century steel industry. Using UFC+TMCP for cooling can improve the strength and toughness of wear-resistant steel.

[0040] In some embodiments, step S4, after laminar cooling, further includes a winding process.

[0041] In some embodiments, the Nb and V elements added to the wear-resistant steel form microalloyed carbonitrides with C and N, respectively, which hinder austenite grain growth and refine the austenite grains, thereby improving both the strength and toughness of the wear-resistant steel. The nanoscale precipitates of Nb can act as hydrogen traps, preventing hydrogen embrittlement of the material.

[0042] In some embodiments, in the step of casting molten steel into thin slabs using a thin slab continuous casting machine, the thickness of the thin slab is 55-65 mm.

[0043] In some embodiments, in the step of heating the slab to a preset temperature using a heating furnace, the preset temperature is 1250–1300°C.

[0044] In some embodiments, the wear-resistant steel comprises, by weight percentage: C 0.62%–0.75%, Si 1.8%–2.2%, Mn 0.8%–1.2%, Cr 0.8%–1.2%, Cu 0.4%–0.8%, Ni 0.9%–1.1%, Al 0.021%–0.037%, P ≤0.01%, S ≤0.01%, N ≤0.005%, Nb 0.011%–0.029%, V 0.063%–0.081%, with the remainder being Fe and unavoidable impurities.

[0045] Wear-resistant steel

[0046] A wear-resistant steel is obtained by the above-described preparation method.

[0047] In some embodiments, the thickness of the wear-resistant steel is 2 to 8 mm.

[0048] In some embodiments, the wear-resistant steel has a Brinell hardness ≥450HBW and an impact energy at room temperature ≥47J.

[0049] In some embodiments, the wear-resistant steel has a Brinell hardness of 510–530 HBW and an impact energy of 60–65 J at room temperature.

[0050] In some embodiments, the wear-resistant steel contains bainite and martensite, wherein the bainite accounts for 90% to 95% and the martensite accounts for 5% to 10%.

[0051] In some embodiments, the tensile strength of the wear-resistant steel is 1260–1400 MPa.

[0052] In some embodiments, the elongation A of the wear-resistant steel 50mm The percentage is 13.5% to 15.2%.

[0053] Examples 1-10

[0054] 1. Prepare materials according to the chemical composition of items 1-10 in Table 1, pour them into the crystallizer through the pouring head of the thin slab continuous casting machine, and then cool them rapidly with cooling water in the crystallizer to solidify the molten steel. After continuous casting, a thin slab is obtained.

[0055] 2. After heating the thin slab to the homogenization temperature corresponding to serial numbers 1-10 in Table 2 using a tunnel-type roller bottom heating furnace, remove the furnace-grown iron oxide scale using a descaling machine.

[0056] 3. A 7-stand hot continuous rolling mill with vertical rolls is used to roll the descaled slab. The reduction rate of the first stand and the final rolling temperature are the parameters corresponding to serial numbers 1-10 in Table 2, to obtain the steel strip of the target thickness.

[0057] 4. Using UFC+TMCP laminar flow cooling, the steel strip is cooled to the cooling temperatures corresponding to serial numbers 1-10 in Table 2 at a cooling rate of 50℃ / s, and then naturally cooled to room temperature to obtain wear-resistant steel coils, which are denoted as 1-10 respectively.

[0058] Table 1. Chemical composition (wt.%) of the wear-resistant steels in Examples 1-10

[0059] Serial Number C Si Mn Cr Cu Ni Al P S N V Nb 1 0.66 2.12 0.87 0.86 0.43 1.09 0.021 0.005 0.003 0.004 0.064 0.022 2 0.65 1.83 0.80 0.88 0.78 0.96 0.023 0.005 0.007 0.002 0.066 0.024 3 0.70 2.16 1.04 0.92 0.64 0.96 0.03 0.007 0.004 0.004 0.073 0.025 4 0.73 1.96 0.97 0.97 0.55 1.01 0.033 0.004 0.009 0.003 0.069 0.019 5 0.64 2.10 0.93 1.05 0.66 1.00 0.027 0.004 0.008 0.005 0.074 0.018 6 0.62 2.17 0.99 0.83 0.58 0.94 0.032 0.005 0.008 0.004 0.081 0.011 7 0.74 2.02 1.02 1.17 0.70 1.10 0.033 0.007 0.006 0.004 0.077 0.016 8 0.71 1.83 0.98 1.20 0.40 1.10 0.030 0.009 0.006 0.004 0.069 0.013 9 0.68 2.04 1.15 1.03 0.57 1.07 0.031 0.005 0.003 0.002 0.063 0.020 10 0.73 1.99 1.12 0.90 0.69 0.94 0.035 0.004 0.002 0.003 0.070 0.029

[0060] Table 2 Process parameters for Examples 1-10

[0061]

[0062]

[0063] Data Analysis

[0064] The wear-resistant steels No. 1-10 prepared in Examples 1-10 were tested for thickness, tensile strength, elongation, room temperature impact energy and Brinell hardness.

[0065] The testing method is as follows:

[0066] Tensile strength was tested using a tensile testing machine.

[0067] Elongation was tested using a tensile testing machine.

[0068] The room temperature impact energy was tested using a Charpy impact testing machine.

[0069] Brinell hardness was tested using a Brinell hardness tester.

[0070] The test results are shown in Table 3:

[0071] Table 3. Test results of wear-resistant steel in Examples 1-10

[0072]

[0073] As shown in Table 3, the wear-resistant steel produced by the CSP production line has excellent comprehensive performance, with high wear resistance (Burl hardness ≥ 420) and high toughness (room temperature impact energy ≥ 47J), and is easy to manufacture continuously and at low cost on the CSP production line.

[0074] The above description is merely a specific implementation of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the protection scope of this application.

Claims

1. A method for preparing wear-resistant steel, characterized in that, include: Molten steel is cast into thin slabs using a thin slab continuous casting machine, and the thin slabs contain austenitic grains; After heating the thin slab to a preset temperature in a heating furnace, a descaling machine is used to descale it, resulting in a thin slab with the furnace-grown iron oxide scale removed. The thin slab after removing the furnace iron oxide scale is rolled using a multi-stand hot continuous rolling mill, wherein the reduction rate of the first stand pass is not less than 60%, and the final rolling temperature is 825-880℃, to obtain a steel strip of the target thickness. The steel strip is cooled to 300-340°C using laminar flow cooling at a cooling rate of 30-80°C / s, and then naturally cooled to room temperature to obtain the wear-resistant steel. The wear-resistant steel comprises, by weight percentage: C 0.62%–0.75%, Si 1.8%–2.2%, Mn 0.8%–1.2%, Cr 0.8%–1.2%, Cu 0.4%–0.8%, Ni 0.9%–1.1%, Al 0.015%–0.05%, P ≤ 0.01%, S ≤ 0.01%, N ≤ 0.005%, Nb 0.01%–0.05%, V 0.05%–0.35%, with the remainder being Fe and unavoidable impurities.

2. The preparation method according to claim 1, characterized in that, In the laminar flow cooling step, the austenite grains in the steel strip are transformed into lower bainite. At the same time, the Cr element dissolved in the austenite grains improves the hardenability of the intermediate slab and promotes the formation of lower bainite and martensite.

3. The preparation method according to claim 1, characterized in that, The Nb and V elements added to the wear-resistant steel form microalloyed carbonitrides with C and N, respectively, which hinder the growth of austenite grains and refine the austenite grains, thereby improving the toughness of the wear-resistant steel while increasing its strength.

4. The preparation method according to claim 1, characterized in that, In the step of casting molten steel into thin slabs using a thin slab continuous casting machine, the thickness of the thin slab is 55-65 mm.

5. The preparation method according to claim 1, characterized in that, In the step of heating the thin slab to a preset temperature using a heating furnace, the preset temperature is 1250-1300℃.

6. The preparation method according to claim 1, characterized in that, The wear-resistant steel comprises, by weight percentage: C 0.62%–0.75%, Si 1.8%–2.2%, Mn 0.8%–1.2%, Cr 0.8%–1.2%, Cu 0.4%–0.8%, Ni 0.9%–1.1%, Al 0.021%–0.037%, P ≤0.01%, S ≤0.01%, N ≤0.005%, Nb 0.011%–0.029%, V 0.063%–0.081%, with the remainder being Fe and unavoidable impurities.

7. A wear-resistant steel, characterized in that, It is obtained by the preparation method according to any one of claims 1-6.

8. The wear-resistant steel according to claim 7, characterized in that, The wear-resistant steel has a thickness of 2 to 8 mm.

9. The wear-resistant steel according to claim 7, characterized in that, The wear-resistant steel has a Brinell hardness ≥450HBW and an impact energy at room temperature ≥47J.

10. The wear-resistant steel according to claim 7, characterized in that, The wear-resistant steel contains bainite and martensite, wherein lower bainite accounts for 90% to 95% and martensite accounts for 5% to 10%.

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