High-strength, high-hardness reinforced wear-resistant steel and method for manufacturing the same

Abstract

The present invention discloses a high-strength, high-hardness reinforced wear-resistant steel containing Fe and unavoidable impurities, and further containing, in mass percent, at least one of C: 0.22-0.33%, Si: 0.10-1.00%, Mn: 0.50-1.80%, Cr: 0.80-2.30%, Al: 0.010-0.10%, RE: 0.01-0.10%, W: 0.01-1.0%; and Mo: 0.01-0.80%, Ni: 0.01-1.00%, Nb: 0.005-0.080%, V: 0.01-0.20%, and Ti: 0.001-0.50%. The present invention also discloses a method for producing the high-strength, high-hardness reinforced wear-resistant steel, comprising the steps of: (1) smelting and casting; (2) heating; (3) rolling; and (4) the cooling start temperature of the first cooling is (Ar3'+5) to (Ar3'+50)°C, and M 90 <Final cooling temperature s , online quenching with cooling rate of 2~15℃ / s; then air cooling to room temperature.​

Description

[Technical Field]

[0001] This invention relates to steel materials and methods for manufacturing the same, and more particularly to wear-resistant steel and methods for manufacturing the same. [Background technology]

[0002] Wear-resistant steel possesses high strength and high wear resistance, and its performance is excellent, making it effectively applied in fields such as mining, agriculture, cement production, ports, power generation, and metallurgy. For example, it can be used to manufacture mechanical products such as bulldozers, loaders, excavators, dump trucks, grabs, and stack feeders, and has a wide range of application prospects.

[0003] In recent years, the development of wear-resistant steel has progressed rapidly, and currently, the most commonly used is martensitic wear-resistant steel. In such wear-resistant steels, the mechanical performance of the wear-resistant steel is generally improved by increasing the carbon content, adding appropriate amounts of alloying elements such as chromium, molybdenum, nickel, vanadium, and boron, and making full use of phase transformation strengthening after heat treatment.

[0004] However, in relatively harsh working conditions, it is often necessary to use wear-resistant steel plates with extremely high hardness. Due to the ultra-high hardness of such wear-resistant steel, the requirements for processing equipment such as machine cutting, drilling, and bending are very high, making machining extremely difficult and causing considerable difficulties for users.

[0005] Based on this, the present invention aims to provide a new high-strength, high-hardness reinforced wear-resistant steel to address the shortcomings and defects of existing wear-resistant steels: it has lower hardness than existing conventional ultra-high-hardness wear-resistant steel sheets, which can greatly benefit users in machining; during actual use, such high-strength, high-hardness reinforced wear-resistant steel is prone to plastic-induced phase transformation, significantly increasing the hardness of the steel sheet and further improving its wear resistance; as a result of this effect, the high-strength, high-hardness reinforced wear-resistant steel according to the present invention achieves higher mechanical and wear resistance than wear-resistant steel sheets of the same hardness level during actual use. [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] One of the objectives of the present invention is to provide a high-strength, high-hardness reinforced wear-resistant steel that has excellent mechanical properties, as well as excellent machinability, thermal stability, and weldability, achieves a combination of high hardness and high toughness, has excellent machinability, and possesses excellent mechanical properties and good wear resistance during actual use, thus having very good prospects for widespread adoption and application value. [Means for solving the problem]

[0007] The high-strength, high-hardness reinforced wear-resistant steel according to the present invention is easy to process, providing convenience for general machining, and during use, it acquires excellent toughness and wear resistance through plastic-induced phase transformation, resulting in superior performance and making it widely applicable to wear-resistant parts in engineering machinery.

[0008] To achieve the above objective, the present invention provides a high-strength, high-hardness, reinforced wear-resistant steel containing Fe and unavoidable impurities, further comprising, by mass percent, at least one of the following: C: 0.22-0.33%, Si: 0.10-1.00%, Mn: 0.50-1.80%, Cr: 0.80-2.30%, Al: 0.010-0.10%, RE: 0.01-0.10%, W: 0.01-1.0%, and Mo: 0.01-0.80%, Ni: 0.01-1.00%, Nb: 0.005-0.080%, V: 0.01-0.20%, and Ti: 0.001-0.50%.

[0009] Furthermore, in the high-strength, high-hardness reinforced wear-resistant steel according to the present invention, the mass percentage of each chemical element is at least one of the following: C: 0.22~0.33%, Si: 0.10~1.00%, Mn: 0.50~1.80%, Cr: 0.80~2.30%, Al: 0.010~0.10%, RE: 0.01~0.10%, W: 0.01~1.0%; and Mo: 0.01~0.80%, Ni: 0.01~1.00%, Nb: 0.005~0.080%, V: 0.01~0.20%, Ti: 0.001~0.50%, with the remainder being Fe and unavoidable impurities.

[0010] In this invention, the high-strength, high-hardness reinforced wear-resistant steel according to the present invention mainly contains C, Si elements and Mn, Cr alloying elements, and may also contain noble metal elements such as Mo and Ni as needed. This makes it possible to keep the cost of the alloy low while ensuring the performance of the steel material.

[0011] In the high-strength, high-hardness reinforced wear-resistant steel according to the present invention, the design principles for each chemical element are as follows: C: In the high-strength, high-hardness reinforced wear-resistant steel according to the present invention, carbon (C) is the most basic and important element in wear-resistant steel. By adding an appropriate amount of C, the strength and hardness of the steel can be increased, and the wear resistance of the steel can be further improved. However, it should be noted that C also has an unfavorable effect on the toughness and weldability of the steel, so it is necessary to rationally control the C content in the steel. Based on this, considering the effect of the C content on the performance of the wear-resistant steel, in the high-strength, high-hardness reinforced wear-resistant steel according to the present invention, the mass percentage of C is controlled to 0.22-0.33%, more preferably to 0.23-0.28%. In some embodiments, the mass percentage of C is 0.22-0.31%. In some embodiments, the mass percentage of C is 0.23-0.31%. In some embodiments, the mass percentage of C is 0.23-0.30%.

[0012] Si: In the high-strength, high-hardness reinforced wear-resistant steel according to the present invention, Si can be dissolved in ferrite and austenite, and can increase their hardness and strength. However, if the Si element content is too high, the toughness of the steel material decreases rapidly. At the same time, considering that the affinity of Si element for O is stronger than that of Fe, low-melting-point silicates are easily generated during welding, which increases the fluidity of slag and molten metal and affects the welding quality, the Si element content in the steel should not be too high. Based on this, in the high-strength, high-hardness reinforced wear-resistant steel according to the present invention, the mass percentage of Si element is controlled to 0.10 to 1.00%. In some embodiments, the mass percentage of Si is 0.10 to 0.80%. In some embodiments, the mass percentage of Si is 0.15 to 0.80%. In some embodiments, the mass percentage of Si is 0.15 to 0.65%.

[0013] Mn: In the high-strength, high-hardness reinforced wear-resistant steel according to the present invention, adding an appropriate amount of Mn significantly improves the hardenability of the steel and reduces the transformation temperature and critical cooling rate of the steel. However, if the Mn content in the steel is too high, it not only tends to coarseen the crystal grains but also increases the temper brittleness susceptibility of the steel, and makes segregation and cracks more likely to occur in the cast slab, thus degrading the performance of the steel plate. Therefore, it should be noted that the Mn content in the steel should not be too high. Based on this, in the high-strength, high-hardness reinforced wear-resistant steel according to the present invention, the mass percentage of Mn is controlled to 0.50 to 1.80%, preferably 1.05 to 1.65%. In some embodiments, the mass percentage of Mn is 1.00 to 1.80%. In some embodiments, the mass percentage of Mn is 1.10 to 1.80%. In some embodiments, the mass percentage of Mn is 1.10 to 1.80%. In some embodiments, the mass percentage of Mn is 1.15 to 1.80%. In some embodiments, the mass percentage of Mn is 0.65 to 1.65%.

[0014] Cr: In the high-strength, high-hardness reinforced wear-resistant steel according to the present invention, the Cr element can reduce the critical cooling rate and improve the hardenability of the steel. Cr is present in the steel as (Fe,Cr)3C, (Fe,Cr)7C3 and (Fe,Cr) 23 Various carbides such as C7 can be formed, effectively increasing the strength and hardness of the steel. Furthermore, by adding an appropriate amount of Cr to the steel, the precipitation and aggregation of carbides during tempering can be prevented or mitigated, thereby improving the tempering stability of the steel. Based on this, considering the beneficial effects of the Cr element, the mass percentage of the Cr element in the high-strength, high-hardness reinforced wear-resistant steel according to the present invention may be controlled to 0.80 to 2.30%, more preferably to 1.25 to 2.10%. In some embodiments, the mass percentage of Cr is 1.10 to 2.20%. In some embodiments, the mass percentage of Cr is 1.10 to 2.00%. In some embodiments, the mass percentage of Cr is 1.15 to 2.00%. In some embodiments, the mass percentage of Cr is 0.95 to 2.10%.

[0015] Al: In the high-strength, high-hardness, reinforced wear-resistant steel according to the present invention, the Al element forms finely soluble AlN particles with the N element in the steel, thereby refining the crystal grains of the steel. By adding an appropriate amount of Al element to the steel, the crystal grains of the steel can be effectively refined, N and O in the steel can be fixed, the susceptibility of the steel to notches can be reduced, the aging phenomenon of the steel can be reduced or eliminated, and the toughness of the steel can be increased. Based on this, in the high-strength, high-hardness, reinforced wear-resistant steel according to the present invention, the mass percentage of the Al element is controlled to 0.010 to 0.10%, more preferably to 0.035 to 0.080%. In some embodiments, the mass percentage of Al is 0.010 to 0.080%. In some embodiments, the mass percentage of Al is 0.015 to 0.075%. In some embodiments, the mass percentage of Al is 0.015 to 0.070%. In some embodiments, the mass percentage of Al is 0.025 to 0.080%.

[0016] RE: In the high-strength, high-hardness, reinforced wear-resistant steel according to the present invention, by adding an appropriate amount of rare earth elements, the segregation of elements such as sulfur and phosphorus is reduced, the shape, size and distribution of nonmetallic inclusions are improved, and at the same time the crystal grains are refined, thereby increasing hardness. In addition, rare earth elements increase the rigidity ratio, which is advantageous in improving the toughness of low-alloy, high-strength steel and can improve the thermal stability of the steel plate. However, if the content of rare earth elements in the steel is too high, serious segregation may occur, which may reduce the quality and mechanical performance of the cast slab, so it should be noted that the content of rare earth elements in the steel should not be too high. Based on this, in the high-strength, high-hardness, reinforced wear-resistant steel according to the present invention, the mass percentage of RE is controlled to 0.01 to 0.10%, more preferably to 0.03 to 0.10%. In some embodiments, the mass percentage of RE is 0.025 to 0.080%.

[0017] W: In the high-strength, high-hardness, reinforced wear-resistant steel according to the present invention, tungsten can improve the tempering stability and thermal strength of the steel and refine certain crystal grains. In addition, tungsten can improve the wear resistance of the steel by forming hard carbides. To exert the beneficial effects of tungsten, the mass percentage of element W in the high-strength, high-hardness, reinforced wear-resistant steel according to the present invention is controlled to 0.01 to 1.0%, more preferably to 0.05 to 0.85%. In some embodiments, the mass percentage of W is 0.05 to 0.85%.

[0018] Mo: In the high-strength, high-hardness reinforced wear-resistant steel according to the present invention, by adding an appropriate amount of Mo, the crystal grains can be effectively refined, thereby increasing the strength and toughness of the steel material. Since Mo exists in both the solid solution phase and the carbide phase in the steel, Mo-containing steel simultaneously plays the role of solid solution strengthening and carbide dispersion strengthening. Furthermore, Mo is an element that reduces temper brittleness, and by adding an appropriate amount of Mo to the steel, the temper stability of the material can be improved. Based on this, in the high-strength, high-hardness reinforced wear-resistant steel according to the present invention, when added, the mass percentage of Mo is controlled to 0.01 to 0.80%, preferably 0.08 to 0.55%.

[0019] Ni: In the high-strength, high-hardness, reinforcement-type wear-resistant steel according to the present invention, Ni can mutually dissolve with Fe in any proportion, refine the ferrite crystal grains, thereby improving the low-temperature toughness of the steel, and significantly reducing the cold brittleness transformation temperature. However, if the content of Ni element in the steel is too high, the oxide scale on the surface of the steel plate is difficult to fall off, which is likely to cause a significant increase in production cost. Therefore, it should be noted that the content of Ni element in the steel should not be too high. Based on this, in the high-strength, high-hardness, reinforcement-type wear-resistant steel according to the present invention, if added, the mass percentage of Ni element is controlled to be 0.01 - 1.00%, preferably 0.25 - 0.85%.

[0020] Nb: In the high-strength, high-hardness, reinforcement-type wear-resistant steel according to the present invention, by adding an appropriate amount of Nb element, it can play the role of grain refinement and precipitation strengthening, and the contribution to the improvement of the strength and toughness of the material is extremely significant; the Nb element can effectively increase the strength and toughness of the steel by the role of grain refinement, and can also improve and enhance the performance of the steel by precipitation strengthening and phase transformation strengthening. Therefore, Nb has already become one of the most effective strengthening agents in high-strength low-alloy structural steel; also, Nb is also a strong carbide and nitride forming element, and can strongly suppress the growth of austenite crystal grains. Based on this, in the high-strength, high-hardness, reinforcement-type wear-resistant steel according to the present invention, if added, the mass percentage of Nb element is controlled to be 0.005 - 0.080%, preferably 0.01 - 0.045%.

[0021] V: In the high-strength, high-hardness, reinforcement-type wear-resistant steel according to the present invention, by adding an appropriate amount of V element, the crystal grains can be effectively refined, and the growth of austenite crystal grains can be prevented from becoming coarse during the heating stage of the steel billet. Thereby, during the subsequent multiple rolling processes, the crystal grains of the steel can be further refined, and the strength and toughness of the steel can be further increased. Based on this, in the high-strength, high-hardness, reinforcement-type wear-resistant steel according to the present invention, if added, the mass percentage of V element is controlled to be 0.01 - 0.20%, preferably 0.03 - 0.15%.

[0022] Ti: In the high-strength, high-hardness, reinforced wear-resistant steel according to the present invention, Ti is one of the strong carbide-forming elements. The Ti element can combine with the C element to form fine TiC particles. Among them, the TiC particles are small and can be distributed at the grain boundaries, thereby realizing the effect of refining the crystal grains; also, the TiC particles are hard and can improve the wear resistance of the steel. Based on this, considering the beneficial effects of the Ti element, in the high-strength, high-hardness, reinforced wear-resistant steel according to the present invention, if added, the mass percentage of the Ti element is controlled to be 0.001 - 0.50%, preferably 0.015 - 0.45%.

[0023] More preferably, in the high-strength, high-hardness, reinforced wear-resistant steel according to the present invention, the mass percentages of each chemical element satisfy C: 0.22 - 0.31%, Si: 0.10 - 0.80%, Mn: 1.00 - 1.80%, Cr: 1.10 - 2.20%, Al: 0.010 - 0.080%.

[0024] Even more preferably, in the high-strength, high-hardness, reinforced wear-resistant steel according to the present invention, the mass percentages of each chemical element satisfy C: 0.23 - 0.31%, Si: 0.15 - 0.80%, Mn: 1.10 - 1.80%, Cr: 1.10 - 2.00%, Al: 0.015 - 0.075%.

[0025] Most preferably, in the high-strength, high-hardness, reinforced wear-resistant steel according to the present invention, the mass percentages of each chemical element satisfy C: 0.23 - 0.30%, Si: 0.15 - 0.65%, Mn: 1.15 - 1.80%, Cr: 1.15 - 2.00%, Al: 0.015 - 0.070%.

[0026] Furthermore, in the high-strength, high-hardness, reinforced wear-resistant steel according to the present invention, in the inevitable impurities, P ≤ 0.030% and / or S ≤ 0.010%.

[0027] In the present invention, P and S are both unavoidable impurities, and to ensure the quality of the wear-resistant steel, it is preferable to have a lower content of impurity elements in the steel, as far as conditions allow. P and S are both harmful elements, and their content should be strictly controlled. Therefore, in the high-strength, high-hardness reinforced wear-resistant steel according to the present invention, the unavoidable impurity elements are controlled to satisfy P ≤ 0.030% and / or S ≤ 0.010%.

[0028] Furthermore, in the high-strength, high-hardness, reinforced wear-resistant steel according to the present invention, the microstructure consists of martensite + bainite + retained austenite + carbide.

[0029] Furthermore, in the high-strength, high-hardness, reinforced wear-resistant steel according to the present invention, the volume fraction of retained austenite is ≥ 5%, and the volume fraction of martensite is ≤ 90%. In some embodiments, in the high-strength, high-hardness, reinforced wear-resistant steel according to the present invention, the volume fraction of retained austenite is 5 to 15%, and the volume fraction of martensite is 60 to 90%. In some embodiments, in the high-strength, high-hardness, reinforced wear-resistant steel according to the present invention, the volume fraction of retained austenite is 5.3 to 12.0%, for example, 5.5 to 8.5%, and the volume fraction of martensite is 70 to 88%, for example, 77.5 to 85.6%.

[0030] Compared to ordinary low-alloy steel sheets of the same hardness level, the high-strength, high-hardness reinforced wear-resistant steel according to the present invention has a microstructure that differs from the current common martensitic structure, forming a microstructure of martensite + bainite + retained austenite + carbide.

[0031] Based on the above microstructure, the mechanical performance of the high-strength, high-hardness reinforced wear-resistant steel according to the present invention can be ensured. This high-strength, high-hardness reinforced wear-resistant steel has a slightly lower hardness, which provides great convenience to the user in machining and is applicable to situations where machining is easy.

[0032] Furthermore, during actual use, the high-strength, high-hardness reinforced wear-resistant steel according to the present invention exhibits excellent wear resistance, mainly due to the TRIP (phase transformation-induced plasticity) effect occurring during use. Specifically, because this steel sheet contains a certain proportion of austenite in addition to a certain amount of martensite or bainite, when the steel sheet is subjected to impact, pressure, and wear during use, a plastic-induced phase transformation occurs, significantly increasing the hardness of the steel sheet and further improving its wear resistance. As a result of this effect, the high-strength, high-hardness reinforced wear-resistant steel according to the present invention can achieve higher mechanical and wear resistance than ordinary wear-resistant steel sheets of the same hardness level during actual use.

[0033] Furthermore, the high-strength, high-hardness reinforced wear-resistant steel according to the present invention, by having a special microstructure and added RE and W elements, can achieve a certain degree of high-temperature resistance, and the hardness loss of this steel sheet is not significant even at high temperatures.

[0034] Furthermore, the high-strength, high-hardness reinforced wear-resistant steel according to the present invention has a Brinell hardness of 400-500 HBW, a tensile strength of 1200-1600 MPa (e.g., 1300-1600 MPa), an elongation of 10-15%, and a Charpy V longitudinal impact energy of >40 J at -40°C.

[0035] In some embodiments, the high-strength, high-hardness reinforced wear-resistant steel according to the present invention has a Brinell hardness of 420-480 HBW, a tensile strength of 1220-1450 MPa, an elongation of 10-15%, and a Charpy V longitudinal impact energy at -40°C > 40 J, for example, 41-60 J.

[0036] In some embodiments, the high-strength, high-hardness, reinforced wear-resistant steel according to the present invention has a yield strength of 800 to 1000 MPa, for example, 830 to 980 MPa. In some embodiments, the high-strength, high-hardness, reinforced wear-resistant steel according to the present invention has a flex ratio of ≤0.75, preferably ≤0.70.

[0037] In some embodiments, the high-strength, high-hardness, reinforced wear-resistant steel according to the present invention is measured to have increased by 10% or more, preferably 13% or more, on the surface of the steel plate after being subjected to an impact energy blow of 550 J. In some embodiments, the high-strength, high-hardness, reinforced wear-resistant steel according to the present invention is measured to have a Brinell hardness of ≥ 480 HBW, for example, 480 to 560 HBW, after being subjected to an impact energy blow of 550 J.

[0038] Accordingly, another objective of the present invention is to provide a simple and feasible method for manufacturing high-strength, high-hardness reinforced wear-resistant steel, the high-hardness reinforced wear-resistant steel produced by this method having excellent overall performance, a Brinell hardness of 400-500 HBW, a tensile strength of 1200-1600 MPa (e.g., 1300-1600 MPa), an elongation of 10-15%, and a Charpy V longitudinal impact energy of >40 J at -40°C, and possessing very good prospects for widespread adoption and application value.

[0039] To achieve the above objective, the present invention provides a method for manufacturing the high-strength, high-hardness, reinforced, wear-resistant steel comprising the following steps: (1) Smelting and casting; (2) heating; (3) Rolling; (4) The starting temperature for the first cooling is (Ar3'+5)~(Ar3'+50)℃, M 90 <Final cooling temperature s Online quenching with a cooling rate of 2-15°C / , followed by air cooling to room temperature.

[0040] In the method for producing high-strength, high-hardness, reinforced wear-resistant steel according to the present invention, each smelting raw material is added according to the chemical composition ratio designed by the inventors, and the high-strength, high-hardness, reinforced wear-resistant steel can be obtained by sequentially going through smelting, casting, heating, rolling, and online quenching processes.

[0041] In addition, in the online quenching process of step (4) above in the present invention, the initial cooling may be performed using water cooling or oil cooling.

[0042] ​ In this invention, Ar3' represents the temperature at which austenite begins to transform into ferrite during online quenching, and B s , Baynay to This indicates the temperature at which metamorphosis begins, M 90 This represents the temperature at which the martensite volume ratio reaches 90%.

[0043] Furthermore, in the manufacturing method described in the present invention, in step (2), the slab heating temperature is controlled to 1030 to 1230°C and maintained at that temperature for 1 to 3 hours. In some embodiments, the slab heating temperature is controlled to 1050 to 1210°C and maintained at that temperature for 1 to 3 hours.

[0044] Furthermore, in the manufacturing method described in the present invention, the slab heating temperature is controlled to 1030 to 1180°C in step (2).

[0045] Accordingly, in some other embodiments, it is more preferable to control the heating temperature to 1030-1160°C; most preferably, the heating temperature is controlled to 1030-1140°C to increase production efficiency and prevent excessive growth of austenite grains and severe oxidation of the slab surface.

[0046] Furthermore, in the manufacturing method according to the present invention, in step (3), the rough rolling temperature is controlled to 930 to 1180°C and the finish rolling temperature to 870 to 970°C. In some embodiments, in step (3), the rough rolling temperature is controlled to 950 to 1150°C and the finish rolling temperature to 885 to 955°C.

[0047] Furthermore, in the manufacturing method according to the present invention, in step (3), the rough rolling temperature is controlled to 930 to 1130°C and the finish rolling temperature to 875 to 945°C.

[0048] Furthermore, in the manufacturing method according to the present invention, in step (3), the rolling reduction ratio in the rough rolling stage is controlled to be more than 35%, and the rolling reduction ratio in the finish rolling stage is controlled to be more than 55%. Furthermore, in the manufacturing method according to the present invention, in step (3), the rolling reduction ratio in the rough rolling stage is controlled to be between 35% and 75%, and the rolling reduction ratio in the finish rolling stage is controlled to be between 55% and 80%.

[0049] More preferably, in some other embodiments, in order to obtain better implementation effects, in the present invention, the rough rolling temperature is controlled to be 930 - 1110°C, the rolling reduction rate in the rough rolling stage is 38% or more, the finish rolling temperature is controlled to be 875 - 935°C, and the rolling reduction rate in the finish rolling stage is 58% or more.

[0050] Most preferably, in step (3), during rolling, the rough rolling temperature is controlled to be 935 - 1105°C, the rolling reduction rate in the rough rolling stage exceeds 40%, the controlled finish rolling temperature is 875 - 930°C, and the rolling reduction rate in the finish rolling stage exceeds 60%.

[0051] Furthermore, in the manufacturing method according to the present invention, in step (4), the cooling start temperature of the initial cooling is (Ar3'+5) - (Ar3'+45)°C, (M 90 + 5°C) < the final cooling temperature < (B s - 15°C), and the cooling rate is 2 - 12°C / S.

[0052] In some other embodiments, the cooling start temperature of the initial cooling is (Ar3'+5) - (Ar3'+40)°C, and the final cooling temperature satisfies (M 90 + 5°C) < the final cooling temperature < (B s - 20°C), and it may be controlled such that the cooling rate is 2 - 11°C / S.

[0053] Most preferably, the cooling start temperature of the initial cooling is (Ar3'+5) - (Ar3'+38)°C, and the final cooling temperature satisfies (M 90 + 5°C) < the final cooling temperature < (B s - 23°C), and the cooling rate may be controlled to be 3 - 11°C / S.

[0054] In some embodiments, the final cooling temperature is 350 - 450°C. In some embodiments, the high-strength high-hardness wear-resistant steel according to the present invention has a thickness of 9 - 25 mm.

[0055] The high-strength, high-hardness reinforced wear-resistant steel and its manufacturing method according to the present invention have the following advantages and beneficial effects compared to the prior art: (1) When designing the chemical composition, in the high-strength, high-hardness, reinforced, wear-resistant steel according to the present invention, the alloy composition is sufficiently optimized, mainly by adding C, Si elements and Mn, CI alloy elements, and by appropriately adding noble metal elements such as Mo and Ni as needed, the alloy cost can be kept low while ensuring the performance of the steel material. (2) From a microstructural perspective, the high-strength, high-hardness reinforced wear-resistant steel according to the present invention has a microstructure of martensite + bainite + retained austenite + carbide (where the volume fraction of martensite is <90%, the volume fraction of retained austenite is >5%, and the excess is bainite and carbide), which causes a TRIP effect in the steel sheet during use, increasing the hardness and wear resistance of the steel sheet, and further improving the practicality and service life of the steel sheet. In addition, hard phases such as Ti, Cr, Mo, and W carbides that are distributed in large quantities and uniformly can further improve the wear resistance and service life of the steel sheet. (3) The high-strength, high-hardness reinforced wear-resistant steel of the present invention has lower hardness than conventional martensitic wear-resistant steel, which greatly benefits the user in machining and is suitable for situations where machining is easy; in addition, by adding RE and W elements, the high-strength, high-hardness reinforced wear-resistant steel of the present invention also has a certain degree of high-temperature resistance, and even at high temperatures, the hardness loss of this steel sheet is not significant.

[0056] Based on the above, the present invention scientifically designs carbon, alloy components, and their mixing ratios under rational production process conditions, reducing alloy costs, and its production process is simple and feasible, making it advantageous for industrial production; accordingly, the high-strength, high-hardness reinforced wear-resistant steel of the present invention possesses excellent mechanical properties (e.g., hardness, strength, elongation, impact toughness, and certain high-temperature resistance), as well as workability and usability, with a Brinell hardness of 400-500 HBW, a tensile strength of 1200-1600 MPa (e.g., 1300-1600 MPa), an elongation of 10-15%, and a Charpy V longitudinal impact energy > 40 J at -40°C, giving it very good prospects for widespread adoption and application value. [Brief explanation of the drawing]

[0057] [Figure 1] Figure 1: Metallurgical image of the high-strength, high-hardness reinforced wear-resistant steel manufactured in Example 3. [Modes for carrying out the invention]

[0058] The following provides further interpretations and explanations of the high-strength, high-hardness reinforced wear-resistant steel and its manufacturing method according to the present invention, by combining specific examples. However, these interpretations and explanations are not intended to unduly limit the configuration to the embodiments of the present invention.

[0059] Examples 1-8 The high-strength, high-hardness, reinforced wear-resistant steels of Examples 1 to 8 were all manufactured using the following process: (1) Smelting and casting were carried out according to the chemical composition ratios shown in Table 1. (2) Heating: The obtained slab was heated, controlling the slab heating temperature to 1030-1230°C and kept warm for 1-3 hours; of course, the slab heating temperature may also be preferably controlled to 1030-1180°C. (3) Rolling: The heated slab was rolled, with the rough rolling temperature controlled to 930-1180°C and the finish rolling temperature to 870-970°C, and the rolling reduction ratio in the rough rolling stage was controlled to more than 35% and the rolling reduction ratio in the finish rolling stage was controlled to more than 55%; of course, when controlling the rolling reduction ratio in the rough rolling stage to more than 35% and the rolling reduction ratio in the finish rolling stage to more than 55%, the rough rolling temperature may preferably be controlled to 930-1130°C and the finish rolling temperature may preferably be controlled to 875-945°C. (4) The starting temperature for the first cooling is ((Ar3'+5)~(Ar3'+50)℃, M 90 <Final cooling temperature s Online quenching with a cooling rate of 2-15°C / s; followed by air cooling to room temperature; preferably, the initial cooling start temperature is (Ar3'+5)-(Ar3'+50)°C and the final cooling temperature is (M 90 +5℃)<Final cooling temperature<(B s The system is controlled to maintain a temperature of -15°C, and the cooling rate is controlled to be between 2 and 12°C / s. ​

[0060] Furthermore, the high-strength, high-hardness, reinforced, wear-resistant steels of Examples 1 to 8 according to the present invention were all manufactured using the above process, and their chemical composition and related process parameters all meet the design specification management requirements of the present invention.

[0061] Table 1 shows the mass percentages of each chemical element in the high-strength, high-hardness reinforced wear-resistant steel of Examples 1 to 8.

[0062] [Table 1]

[0063] Tables 2-1 and 2-2 show the specific process parameters in each step of the above manufacturing method for the high-strength, high-hardness reinforced wear-resistant steel of Examples 1 to 8.

[0064] [Table 2-1]

[0065] [Table 2-2]

[0066] Note: In Table 2-2, Ar3' represents the temperature at which austenite begins to transform into ferrite during online quenching of the test steel, B s This represents the temperature at which baynite begins to metamorphose, M 90 This represents the temperature at which the martensite volume ratio reaches 90%.

[0067] Finally, samples were taken from each of the high-hardness reinforced wear-resistant steels obtained in Examples 1 to 8. The samples of high-hardness reinforced wear-resistant steels from Examples 1 to 8 were observed and analyzed. From the observation, it was found that the microstructure of all high-hardness reinforced wear-resistant steels from Examples 1 to 8 consisted of martensite + bainite + retained austenite + carbide. A photograph of the metallographic structure of Example 3 is shown in Figure 1.

[0068] Accordingly, further analysis was performed on the microstructure of the high-hardness, reinforced, wear-resistant steels of Examples 1 to 8 to obtain the volume fractions of the retained austenite structure and the martensite structure. Here, the volume fraction of retained austenite was >5% in all cases, and the volume fraction of martensite was <90% in all cases. The results for the volume fraction of the retained austenite structure are shown in Table 3 below.

[0069] [Table 3]

[0070] From Table 3 above, it can be seen that the high-strength, high-hardness reinforced wear-resistant steels of Examples 1 to 8 according to the present invention have a volume fraction of retained austenite of 5.6 to 8.3%.

[0071] After completing the microstructural observation of the high-strength, high-hardness reinforced wear-resistant steels of Examples 1 to 8 of the present invention, the mechanical performance of the high-strength, high-hardness reinforced wear-resistant steel samples of Examples 1 to 8 was further tested to obtain the mechanical performance parameters of the high-hardness reinforced wear-resistant steels of Examples 1 to 8. The obtained test results are shown in Table 4 below.

[0072] The testing methods for correlational dynamics performance are as follows: Tensile Test: Tensile performance tests were conducted at room temperature using an SCL 233200kN room temperature tensile testing machine in accordance with the GB / T 228.1 standard, and the tensile strength and elongation of the high-strength, high-hardness reinforced wear-resistant steel samples of Examples 1 to 8 were measured at room temperature.

[0073] Cold bending test: Bending tests were performed at room temperature on each of the high-strength, high-hardness reinforced wear-resistant steels of Examples 1 to 8, and corresponding results were obtained. The bending tests were performed at room temperature using a YJW-2000 electro-hydraulic server bending tester in accordance with the GB / T232 standard. After the bending test, the sample was observed without using an expansion device, and if no cracks were observed on the outer surface of the sample, it was judged as "pass".

[0074] Brinell hardness testing: Brinell hardness testing was performed at room temperature using an SCL 246 Brinell hardness tester, in accordance with the GB / T 231.1 standard. Hardness testing was performed on the surface of each of the high-strength, high-hardness reinforced wear-resistant steel samples from Examples 1 to 8, and the Brinell hardness for the corresponding example was obtained.

[0075] After obtaining the Brinell hardness of the high-hardness, high-hardness reinforced wear-resistant steel samples of Examples 1 to 8, the steel plates of each example were subjected to an impact energy of 550 J using a self-made hammering device, and the Brinell hardness of the steel plate surface was measured to obtain the Brinell hardness after reinforcement.

[0076] Impact Test: An impact performance test was conducted at -40°C using an SCL 186750J instrumented impact tester, in accordance with GB / T 229. Impact toughness was tested for each of the high-strength, high-hardness reinforced wear-resistant steel samples from Examples 1 to 8, and the corresponding impact energy was obtained.

[0077] Table 4 shows the results of the mechanical performance tests at the surface location of the high-strength, high-hardness reinforced wear-resistant steels of Examples 1 to 8.

[0078] [Table 4]

[0079] Note: Hardness after strengthening: Brinell hardness of the steel plate surface measured after applying a 550J impact energy to the sample steel plate using a self-made hammering device.

[0080] As shown in Table 4 above, the high-strength, high-hardness reinforced wear-resistant steels of Examples 1 to 8 according to the present invention possess excellent mechanical properties, not only having characteristics such as high strength, high hardness, and high elongation, but also excellent low-temperature impact toughness, with a yield strength of 835 to 980 MPa, a tensile strength of 1240 to 1415 MPa, an elongation of 12 to 15%, a surface Brinell hardness of 422 to 475 HBW, and a Charpy V longitudinal impact energy of 42 to 57 J at -40°C.

[0081] The high-hardness, high-hardness reinforced wear-resistant steels of Examples 1 to 8 according to the present invention retained good Brinell hardness even after strengthening. The Brinell hardness of the steel plates after strengthening in each example, measured after impacting the sample steel plates with 550 J of impact energy using a self-made hammering device, ranged from 493 to 545 HBW.

[0082] Accordingly, the high-strength, high-hardness reinforced wear-resistant steels of Examples 1 to 8 according to the present invention all exhibited excellent cold bending performance, and no cracks were observed on the outer surface of the samples after bending tests, resulting in all of them passing the test. Because the steel plates according to the present invention have extremely low yield strength, they exhibit significantly superior forming performance, such as bending, compared to ordinary wear-resistant steels of the same hardness level.

[0083] Based on the above, the high-strength, high-hardness, reinforced wear-resistant steel according to the present invention provides a wear-resistant steel with a microstructure of martensite + bainite + retained austenite + carbide through rational chemical elemental composition design and formulation optimization technology; this high-strength, high-hardness, reinforced wear-resistant steel possesses excellent mechanical properties (e.g., hardness, strength, elongation, impact toughness, and a certain degree of high-temperature resistance) while also having good workability and usability.

[0084] The high-strength, high-hardness reinforced wear-resistant steel according to the present invention is not only easy to process and convenient for ordinary machining, but also possesses excellent toughness and wear resistance during use, making it widely applicable to wear-resistant parts in engineering machinery.

[0085] Furthermore, the prior art portion within the scope of protection of the present invention is not limited to the embodiments described in this application, but includes, but is not limited to, all prior art, prior patent documents, prior publications, prior use, etc. that are not inconsistent with aspects of the present invention.

[0086] Furthermore, the combination methods of each technical feature in this case are not limited to the combination methods described in the claims or the combination methods described in the specific embodiments. All technical features described in this case may be freely combined or combined in any manner, as long as they do not conflict with each other.

[0087] It should be noted that the above-mentioned examples are only specific embodiments of the present invention, and it is clear that the present invention is not limited to the above embodiments, and that there are many similar variations. All modifications that can be directly derived from the disclosure of the present invention or that can be conceivable by those skilled in the art are included within the scope of protection of the present invention.

Claims

1. A high-strength, high-hardness reinforced wear-resistant steel comprising the following mass percentages of each chemical element: C, Si, Mn, Cr, Al, RE, and W: C: 0.22-0.33%, Si: 0.10-1.00%, Mn: 0.50-1.80%, Cr: 0.80-2.30%, Al: 0.010-0.10%, RE: 0.01-0.10%, W: 0.01-1.0%. The aforementioned high-strength, high-hardness reinforced wear-resistant steel further contains at least one chemical element selected from the group consisting of Mo, Ni, Nb, V, and Ti in the following mass percentages: Mo: 0.01-0.80%, Ni: 0.01-1.00%, Nb: 0.005-0.080%, V: 0.01-0.20%, Ti: 0.001-0.50%. The remainder consists of Fe and unavoidable impurities. The aforementioned high-strength, high-hardness, reinforced wear-resistant steel is a high-strength, high-hardness, reinforced wear-resistant steel having a microstructure of martensite + bainite + retained austenite + carbide.

2. The high-strength, high-hardness, reinforced wear-resistant steel according to claim 1, wherein the mass percentages of each chemical element are: C: 0.22–0.31%, Si: 0.10–0.80%, Mn: 1.00–1.80%, Cr: 1.10–2.20%, and Al: 0.010–0.080%.

3. The high-strength, high-hardness, reinforced wear-resistant steel according to Claim 1, wherein the mass percentages of each chemical element are: C: 0.23-0.31%, Si: 0.15-0.80%, Mn: 1.10-1.80%, Cr: 1.10-2.00%, and Al: 0.015-0.075%.

4. The high-strength, high-hardness, reinforced wear-resistant steel according to Claim 1, wherein the mass percentages of each chemical element are: C: 0.23-0.30%, Si: 0.15-0.65%, Mn: 1.15-1.80%, Cr: 1.15-2.00%, and Al: 0.015-0.070%.

5. The high-strength, high-hardness, reinforced wear-resistant steel according to claim 1, wherein the mass percentage of chemical elements has one or more of the following characteristics. The carbon content is 0.23–0.28%; the silicon content is 0.15–0.65%; the manganese content is 1.05–1.65%; the chromium content is 1.25–2.10%; and the algal content is 0.035–0.080%.

6. The high-strength, high-hardness, reinforced wear-resistant steel according to claim 1, wherein the content of P, an unavoidable impurity, is P ≤ 0.030%, and the content of S, an unavoidable impurity, is S ≤ 0.010%.

7. The high-strength, high-hardness, reinforced wear-resistant steel according to claim 1, wherein the volume fraction of retained austenite is ≥ 5% and the volume fraction of martensite is ≤ 90%.

8. The high-strength, high-hardness, reinforced wear-resistant steel according to Claim 1, wherein the volume fraction of retained austenite is 5 to 15% and the volume fraction of martensite is 60 to 90%.

9. The high-strength, high-hardness, reinforced wear-resistant steel according to Claim 1, wherein the volume fraction of retained austenite is 5.3 to 12.0% and the volume fraction of martensite is 70 to 88%.

10. The high-strength, high-hardness, reinforced wear-resistant steel according to claim 9, wherein the volume fraction of retained austenite is 5.5 to 8.5%.

11. The high-strength, high-hardness, reinforced wear-resistant steel according to claim 9, wherein the volume fraction of martensite is 77.5 to 85.6%.

12. The high-strength, high-hardness, reinforced wear-resistant steel according to claim 1, having a Brinell hardness of 400 to 500 HBW, a tensile strength of 1200 to 1600 MPa, an elongation of 10 to 15%, and a Charpy V-type longitudinal impact energy > 40 J at -40°C.

13. The high-strength, high-hardness, reinforced wear-resistant steel according to Claim 1, wherein the yield strength is 800 to 1000 MPa.

14. The high-strength, high-hardness, reinforced wear-resistant steel according to claim 1, wherein the yield strength is 830 to 980 MPa.

15. The high-strength, high-hardness reinforced wear-resistant steel according to Claim 1, wherein the strength ratio is ≤0.

75.

16. The high-strength, high-hardness reinforced wear-resistant steel according to Claim 1, wherein the strength ratio is ≤0.

70.

17. A method for manufacturing high-strength, high-hardness, reinforced wear-resistant steel according to any one of claims 1 to 16, comprising the following steps. (1) Smelting and casting; (2) Heating; (3) Rolling; (4) The starting temperature for the initial cooling is (Ar3'+5) to (Ar3'+50)°C, M ９０ <Final cooling temperature <B ｓ Online quenching with a cooling rate of 2-15°C / day; followed by air cooling to room temperature.

18. The manufacturing method according to claim 17, wherein in step (2), the slab heating temperature is controlled to 1030 to 1230°C and the temperature is maintained for 1 to 3 hours.

19. The manufacturing method according to claim 18, wherein in step (2), the slab heating temperature is controlled to 1030 to 1180°C.

20. The manufacturing method according to claim 17, wherein in step (3), the rough rolling temperature is controlled to 930 to 1180°C and the finish rolling temperature to 870 to 970°C.

21. The manufacturing method according to claim 20, wherein in step (3), the rough rolling temperature is controlled to 930 to 1130°C and the finish rolling temperature is controlled to 875 to 945°C.

22. The manufacturing method according to claim 17, wherein in step (3), the rolling reduction ratio in the rough rolling stage is controlled to be more than 35%, and the rolling reduction ratio in the finish rolling stage is controlled to be more than 55%.

23. In step (4), the initial cooling start temperature is (Ar3'+5) to (Ar3'+45)°C, and (M ９０ +5℃)<Final cooling temperature<(B ｓ The manufacturing method according to claim 17, wherein the temperature is -15°C and the cooling rate is 2 to 12°C / S.

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