A low-crack-sensitive ultra-high-grade wear-resistant steel plate and a preparation method thereof
By optimizing the chemical composition and process flow, the problem of easy cracking of ultra-high grade wear-resistant steel during processing was solved, achieving low crack sensitivity under high hardness and high strength, improving processing adaptability, and enhancing product qualification rate and safety.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANJING IRON & STEEL CO LTD
- Filing Date
- 2026-03-02
- Publication Date
- 2026-06-05
AI Technical Summary
Existing ultra-high grade wear-resistant steel is prone to cracking during processing, affecting product qualification rate and service safety, and it is difficult to improve its processing adaptability under high hardness and high strength.
By optimizing the chemical composition and process flow, including precise control of strengthening alloying elements such as Mn, Cr, Mo, and Ni, adding rare earth cerium-iron alloys for deep deoxidation, and adopting controlled rolling and slow cooling processes, combined with pre-heat treatment and quenching and tempering processes, the grains are refined and segregation and internal stress are reduced.
It significantly reduces the crack sensitivity of steel plates, reducing the crack rate from 10% to less than 1%, while ensuring high hardness and high strength, improving processing adaptability, and enhancing plasticity and toughness.
Smart Images
Figure SMS_1
Abstract
Description
Technical Field
[0001] This invention relates to a steel plate and its preparation method, specifically to a low-crack-sensitivity ultra-high-grade wear-resistant steel plate and its preparation method, belonging to the field of steel production technology. Background Technology
[0002] Wear-resistant steel, with its excellent comprehensive mechanical properties, has become the most widely used wear-resistant material in mining, machinery, metallurgy, and military industries. Under the background of energy conservation, emission reduction, and the "dual carbon" target, downstream industries have placed higher demands on the wear resistance and service life of equipment. Key components such as mine car bodies, scraper conveyors, and screens are gradually adopting higher-grade wear-resistant steels, with Brinell hardness reaching 500HB–620HB and tensile strength as high as 1500–2300MPa. However, with the increase in strength and hardness, this type of ultra-high-strength wear-resistant steel also faces severe challenges in production and application: due to its high stress level and relatively low plasticity reserve, it is extremely prone to cracking during processing such as cutting and welding, which not only seriously affects the product qualification rate and service safety but also brings significant economic losses to manufacturers and end users.
[0003] Currently, patent CN121272300A describes a high-wear-resistant, environmentally friendly, pre-hardened, low-crack-sensitivity saw blade steel and its manufacturing method. The manufactured saw blade steel has a thickness of 6-12mm, a width ≤4800mm, an unevenness ≤5mm / 2m, a 24-hour wear rate <20mg, a yield strength ≥1135MPa, a tensile strength ≥1468MPa, an elongation ≥21%, a room temperature impact energy (AKV) ≥145J, a hardness of 43-48HRC, and a tooth tip quenching hardness ≥58HRC. Patent CN103397272B describes a wear-resistant steel plate with low crack sensitivity index and high strength, and its preparation method. This wear-resistant steel plate has low carbon content, good weldability, low added precious metal content, and low cost. Its weld crack sensitivity index (Pcm) is below 0.30%, and its Brinell hardness value HBW430-470 can reach NM450. The wear-resistant steel plate of this grade can better meet the welding requirements of relevant application industries for NM450 wear-resistant steel plates; the two patents mentioned above have low strength, thin thickness, low cracking sensitivity, and low production difficulty.
[0004] Therefore, how to improve the adaptability of wear-resistant steel to processing technology while ensuring high hardness and high strength has become a key issue that urgently needs to be addressed in the current research and application of wear-resistant steel. Summary of the Invention
[0005] The technical problem to be solved by the present invention is to provide a low-crack-sensitivity ultra-high-grade wear-resistant steel plate and its preparation method, in view of the shortcomings of the above-mentioned prior art.
[0006] The technical solution of this invention to solve the above technical problems is: A low-crack-sensitivity ultra-high-grade wear-resistant steel plate has the following chemical composition by mass percentage: C: 0.26%–0.48%, Si: 0.15%–0.35%, Mn: 0.3%–0.6%, Nb: 0.035%–0.065%, Mo: 0.001%–0.50%, Ni: 0.001%–0.30%, V: 0.035%–0.065%, Ti: 0.002%–0.006%, Cr: 1.2%–2.5%, B: 0.0003%–0.0020%, Alt: 0.04%–0.075%, N≤0.0050%, H≤0.0002%, P≤0.015%, S≤0.0020%, Ce≥5ppm, with the remainder being Fe and unavoidable impurities. The sum of all the above components is 100%.
[0007] The technical solution further defined in this invention is as follows: Furthermore, the chemical composition of the aforementioned low-crack-sensitivity ultra-high-grade wear-resistant steel plate, by mass percentage, is as follows: C: 0.26%–0.29%, Si: 0.20%–0.30%, Mn: 0.4%–0.5%, Nb: 0.035%–0.050%, Mo: 0.001%–0.50%, Ni: 0.001%–0.30%, V: 0.035%–0.050%, Ti: 0.002%–0.004%, Cr: 1.6%–1.8%, B: 0.0005%–0.0018%, Alt: 0.055%–0.065%, N≤0.0035%, H≤0.00012%, P≤0.015%, S≤0.0020%, Ce≥5ppm, with the remainder being Fe and unavoidable impurities. The sum of all the above components is 100%.
[0008] The aforementioned ultra-high wear-resistant steel plate with low crack sensitivity has the following chemical composition by mass percentage: C: 0.30%–0.35%, Si: 0.15%–0.25%, Mn: 0.3%–0.45%, Nb: 0.030%–0.045%, Mo: 0.001%–0.50%, Ni: 0.001%–0.30%, V: 0.035%–0.045%, Ti: 0.002%–0.004%, Cr: 1.2%–1.4%, B: 0.0008%–0.0015%, Alt: 0.055%–0.065%, N≤0.0035%, H≤0.00012%, P≤0.015%, S≤0.0020%, Ce≥5ppm, with the remainder being Fe and unavoidable impurities. The sum of all the above components is 100%.
[0009] The aforementioned ultra-high wear-resistant steel plate with low crack sensitivity has the following chemical composition by mass percentage: C: 0.43%–0.45%, Si: 0.15%–0.25%, Mn: 0.30%–0.45%, Nb: 0.035%–0.055%, Mo: 0.001%–0.50%, Ni: 0.001%–0.30%, V: 0.035%–0.045%, Ti: 0.002%–0.004%, Cr: 1.2%–1.4%, B: 0.0006%–0.0015%, Alt: 0.055%–0.065%, N≤0.0035%, H≤0.00012%, P≤0.015%, S≤0.0020%, Ce≥5ppm, with the remainder being Fe and unavoidable impurities. The sum of all the above components is 100%.
[0010] This invention also designs a method for preparing ultra-high grade wear-resistant steel plates with low crack sensitivity. The process is as follows: hot metal desulfurization pretreatment - converter smelting - LF+RH refining - continuous casting - billet cooling - billet acceptance - billet heating - descaling - rolling - steel plate cooling - flaw detection - preheat treatment - shot blasting - quenching - tempering - straightening - cutting and sampling - marking - inspection - warehousing, wherein: The rolling process adopts controlled rolling technology, and the thickness of the strip billet is controlled to be (mm) (1.5~3)*h, where h is the thickness of the finished steel plate in mm, and the final rolling temperature is ≤ the quenching temperature. After rolling, the steel plate needs to be slowly cooled in a heated insulation pit. The slow cooling time (hours) is set according to the thickness of the steel plate as (10~20)*h, where h is the thickness of the finished steel plate in cm. Preferably, the maximum time should not exceed 12 days. Before offline quenching, preheating treatment is performed at a temperature between 500 and 800℃. The heat treatment time (minutes) is (4 to 10) * h, where h is the thickness of the finished steel plate in mm. Preferably, the maximum time is no more than 900 minutes.
[0011] The technical solution further defined in this invention is as follows: In the aforementioned method for preparing ultra-high wear-resistant steel plates with low crack sensitivity, the mass fraction of S in the molten iron after desulfurization pretreatment and slag removal is ≤0.0025%.
[0012] In the aforementioned method for preparing ultra-high wear-resistant steel plates with low crack sensitivity, 50-200 kg of 5%-40% rare earth cerium-iron alloy is added during the converter tapping process.
[0013] In the aforementioned method for preparing ultra-high wear-resistant steel plates with low crack sensitivity, the tundish baking time during continuous casting is ≥5 hours.
[0014] In the aforementioned method for preparing ultra-high wear-resistant steel plates with low crack sensitivity, the quenching temperature is 830~930℃ and the tempering temperature is 120~220℃.
[0015] In the aforementioned method for preparing ultra-high wear-resistant steel plates with low crack sensitivity, the prepared steel plates have a Brinell hardness of 500HB to 620HB, a strength of 1500 to 2300 MPa, and a crack incidence rate of ≤1% during the cutting process.
[0016] The beneficial effects of this invention are: (1) In terms of composition optimization, this invention optimizes the composition by precisely controlling strengthening alloying elements such as Mn, Cr, Mo, and Ni, and optimizing microalloying elements such as Nb, V, Ti, and Al. This ensures that all mechanical properties meet national standards while effectively reducing the segregation index. Specifically: Mn primarily functions as an economical and efficient element for improving the hardenability of steel plates. It also exhibits significant solid solution strengthening effects, significantly reducing the transformation temperature (Ar3 point) of austenite to ferrite and pearlite, and refining ferrite grains at room temperature. However, Mn is a positive segregation element, and adding excessive Mn will exacerbate the segregation index. This invention precisely controls its content to 0.3%–0.6%. Cr improves hardenability, corrosion resistance and high-temperature oxidation resistance. This invention precisely controls its content to 1.2% to 2.5% to achieve the best balance between cost and performance. It forms carbides such as (Fe,Cr)7C3 with carbon, which improves wear resistance. However, the amount is controlled at 1.2% to 2.5% to avoid excessive amount leading to a decrease in toughness. Mo, a powerful hardenability element, far surpasses Mn and Cr in its effects, ensuring uniform mechanical properties in steel plates after heat treatment. It also effectively improves the stability of the austenite phase region and suppresses grain coarsening at high temperatures, resulting in a more uniform and finer microstructure after heat treatment. This refining effect not only directly contributes to increased material strength but also improves plasticity and low-temperature toughness. This invention precisely controls its content to be 0.001%–0.50%. Ni can improve strength and hardenability without significantly reducing toughness, and can lower the brittle transition temperature, making it the most critical element for improving low-temperature toughness. The Ni-Cr-Mo-Mn combination achieves a combination of high strength, high hardenability, and excellent toughness.
[0017] Nb, as a strong grain refiner and precipitation strengthener, precipitates in austenite during hot rolling, strongly pinning grain boundaries and delaying recrystallization. Through controlled rolling in the non-recrystallized zone, the austenite grains are significantly refined, thus achieving the effect of grain refinement and better weldability. Vanadium (V) plays a crucial role in steel primarily through the formation of carbonitrides (V(C,N)). These fine particles strongly impede dislocation movement (precipitation strengthening), significantly enhancing the strength of the steel. They also pin grain boundaries and refine grains, maintaining or improving toughness while increasing strength. Vanadium has a strong affinity for hydrogen, acting as a "deep trap" to firmly capture hydrogen atoms, permanently fixing them in the crystal lattice and significantly reducing the content of freely diffusing, embrittlement-causing hydrogen. Ti primarily functions to fix nitrogen and prevent N from forming boron nitride with B, which would affect hardenability. However, excessive Ti content can lead to the formation of angular TiN, which can easily cause cracking of the steel plate. In this invention, the Ti content is controlled at 0.002% to 0.006%.
[0018] Al, the main deoxidizer and important grain refiner, forms Al2O3, which purifies the molten steel. The solute Al can pin the grain boundaries and inhibit the growth of austenite grains. Since the Ti content is reduced, sufficient Al is needed to replace Ti for nitrogen fixation. The Al content in this invention is 0.040% to 0.075%.
[0019] (2) During the converter tapping process, 50-200 kg of rare earth alloy is added for deep deoxidation and inclusion modification to improve the purity of the molten steel. Specifically: Rare earth elements have far stronger deoxidation and desulfurization capabilities than aluminum and calcium. When added during steelmaking, they can react with trace amounts of residual oxygen and sulfur in the molten steel to form high-melting-point rare earth oxides (such as Ce2O3) and rare earth oxysulfides (such as Ce2O2S), further reducing the dissolved oxygen and sulfur content in the steel. This results in "cleaner" molten steel than traditional aluminum deoxidation, laying the foundation for high-performance steel grades. Rare earth elements can also "spheroidize" and refine inclusions. Even after calcium treatment, some harmful inclusions such as Al2O3 and MnS will still exist in the steel. Al2O3 is clustered, hard, and brittle, while MnS tends to extend along the rolling direction during hot working, forming strips that severely deteriorate the transverse properties and toughness of the steel. Rare earth elements can modify these harmful inclusions into rare earth inclusions with an elastic modulus closer to that of the steel matrix.
[0020] (3) The steel rolling adopts the controlled rolling process to ensure a certain amount of temperature-controlled billet thickness. Combined with the large reduction of a single pass of the 5000mm rolling mill, it ensures fine grain size and improves crack resistance.
[0021] (4) After rolling, the steel plates are stacked in a heated insulation pit for slow cooling to reduce internal stress and H content.
[0022] (5) After the steel plates are stacked and slow cooled, they are preheated to eliminate the high internal stress and brittleness of the mixed structure of pearlite, martensite, bainite and other structures in the hot-rolled matrix, to homogenize the structure, and to further reduce the H content in the steel plate and reduce crack sensitivity.
[0023] (6) The steel plate prepared by the present invention has low crack sensitivity, and the crack rate is reduced from 10% in conventional processes to less than 1%. Detailed Implementation
[0024] To make the content of this invention easier to understand, the invention will be further described in detail below based on specific embodiments and performance. This embodiment is implemented based on the technical solution of this invention, providing detailed implementation methods and specific operating procedures. However, the scope of protection of this invention is not limited to the following embodiments. All other embodiments obtained by those skilled in the art based on the given embodiments without innovative effort are within the scope of protection of this application. Example 1
[0025] This embodiment provides a low-crack-sensitivity ultra-high-grade wear-resistant steel plate, the chemical composition of which is as follows by mass percentage: C: 0.27%, Si: 0.23%, Mn: 0.46%, Nb: 0.040%, Mo: 0.12%, Ni: 0.15%, V: 0.040%, Ti: 0.003%, Cr: 1.7%, B: 0.0012%, Alt: 0.060%, N: 0.0032%, H: 0.00011%, P: 0.008%, S: 0.0005%, Ce: 16ppm, with the remainder being Fe and unavoidable impurities, and the sum of the above components is 100%.
[0026] The preparation method of the above-mentioned low-crack-sensitivity ultra-high-grade wear-resistant steel plate is as follows: hot metal desulfurization pretreatment - converter smelting - LF+RH refining - continuous casting - billet cooling - billet acceptance - billet heating - descaling - rolling - steel plate cooling - flaw detection - preheat treatment - shot blasting - quenching - tempering - straightening - cutting and sampling - marking - inspection - warehousing, wherein: The mass fraction of sulfur in the molten iron after desulfurization pretreatment and slag removal is ≤0.0025%; 150 kg of 5%-40% rare earth cerium ferroalloy is added during the converter tapping process; the alloy must be pre-baked when adding alloy in LF, and the baking time of the tundish during continuous casting is 6 hours; a controlled rolling process is adopted during rolling, controlling the thickness of the strip billet to 160 mm and the final rolling temperature to 873℃; the rolled steel plate needs to be slowly cooled in a heated insulation pit, and the slow cooling time (hours) is set according to the thickness of the steel plate to 162 hours; preheating is carried out before offline quenching, the heat treatment temperature is 685℃, and the heat treatment time (minutes) is 725 minutes; the quenching temperature is 880℃, and the tempering temperature is 200℃.
[0027] The thickness, mechanical properties and cracking rate of the steel plate prepared by the above method are shown in Table 1. Example 2
[0028] This embodiment provides a low-crack-sensitivity ultra-high-grade wear-resistant steel plate, the chemical composition of which is as follows by mass percentage: C: 0.33%, Si: 0.21%, Mn: 0.40%, Nb: 0.038%, Mo: 0.35%, Ni: 0.20%, V: 0.036%, Ti: 0.003%, Cr: 1.3%, B: 0.0009%, Alt: 0.062%, N: 0.0025%, H: 0.0001%, P: 0.010%, S: 0.0008%, Ce: 12ppm, with the remainder being Fe and unavoidable impurities, and the sum of the above components is 100%.
[0029] The preparation method of the above-mentioned low-crack-sensitivity ultra-high-grade wear-resistant steel plate is as follows: hot metal desulfurization pretreatment - converter smelting - LF+RH refining - continuous casting - billet cooling - billet acceptance - billet heating - descaling - rolling - steel plate cooling - flaw detection - preheat treatment - shot blasting - quenching - tempering - straightening - cutting and sampling - marking - inspection - warehousing, wherein: The mass fraction of sulfur in the molten iron after desulfurization pretreatment and slag removal is ≤0.0025%; 150 kg of 5%-40% rare earth cerium ferroalloy is added during the converter tapping process; the alloy must be pre-baked when adding alloy in LF, and the baking time of the tundish during continuous casting is 7 hours; a controlled rolling process is adopted during rolling, the thickness of the strip billet is controlled to 150 mm, and the final rolling temperature is 855℃; the rolled steel plate needs to be slowly cooled in a heated insulation pit for 160 hours, and the steel plate is pre-heat treated at a temperature of 750℃ for 700 minutes, with a quenching temperature of 870℃ and a tempering temperature of 200℃.
[0030] The thickness, mechanical properties and cracking rate of the steel plate prepared by the above method are shown in Table 1. Example 3
[0031] This embodiment provides a low-crack-sensitivity ultra-high-grade wear-resistant steel plate, the chemical composition of which is as follows by mass percentage: C: 0.44%, Si: 0.22%, Mn: 0.43%, Nb: 0.039%, Mo: 0.18%, Ni: 0.25%, V: 0.042%, Ti: 0.0029%, Cr: 1.28%, B: 0.0008%, Alt: 0.062%, N: 0.0032%, H: 0.00009%, P: 0.005%, S: 0.0007%, Ce: 25ppm, with the remainder being Fe and unavoidable impurities, and the sum of the above components is 100%.
[0032] The preparation method of the above-mentioned low-crack-sensitivity ultra-high-grade wear-resistant steel plate is as follows: hot metal desulfurization pretreatment - converter smelting - LF+RH refining - continuous casting - billet cooling - billet acceptance - billet heating - descaling - rolling - steel plate cooling - flaw detection - preheat treatment - shot blasting - quenching - tempering - straightening - cutting and sampling - marking - inspection - warehousing, wherein: The mass fraction of sulfur in the molten iron after desulfurization pretreatment and slag removal is ≤0.0025%; 160 kg of 5%-40% rare earth cerium-iron alloy is added during the converter tapping process; the tundish baking time during continuous casting is 10 hours; a controlled rolling process is adopted during rolling, controlling the thickness of the strip billet to 136 mm, and the final rolling temperature is 852℃; the rolled steel plate needs to be slowly cooled in a heated insulation pit for 152 hours; preheating is carried out before offline quenching, with the heat treatment temperature between 660℃ and the heat treatment time (minutes) being 800 minutes; the quenching temperature is 860℃, and the tempering temperature is 165℃.
[0033] The thickness, mechanical properties and cracking rate of the steel plate prepared by the above method are shown in Table 1.
[0034] Table 1 Mechanical properties of steel plates
[0035] As can be seen from Table 1 above, the method of the present invention can improve the adaptability of processing technology while ensuring high thickness, high hardness and high strength. It can effectively solve the problem of cracking that is prone to occur in processing links such as cutting and welding, without affecting the product qualification rate and service safety.
[0036] In addition to the embodiments described above, the present invention may have other implementations. All technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.
Claims
1. A low-crack-sensitivity ultra-high-grade wear-resistant steel plate, characterized in that: Its chemical composition by mass percentage is as follows: C: 0.26%–0.48%, Si: 0.15%–0.35%, Mn: 0.3%–0.6%, Nb: 0.035%–0.065%, Mo: 0.001%–0.50%, Ni: 0.001%–0.30%, V: 0.035%–0.065%, Ti: 0.002%–0.006%, Cr: 1.2%–2.5%, B: 0.0003%–0.0020%, Alt: 0.04%–0.075%, N≤0.0050%, H≤0.0002%, P≤0.015%, S≤0.0020%, Ce≥5ppm, with the remainder being Fe and unavoidable impurities. The sum of all the above components is 100%.
2. The low crack sensitivity ultra-high grade wear-resistant steel plate according to claim 1, characterized in that: Its chemical composition by mass percentage is as follows: C: 0.26%~0.29%, Si: 0.20%~0.30%, Mn: 0.4%~0.5%, Nb: 0.035%~0.050%, Mo: 0.001%~0.50%, Ni: 0.001%~0.30%, V: 0.035%~0.050%, Ti: 0.002%~0.004%, Cr: 1.6%~1.8%, B: 0.0005%~0.0018%, Alt: 0.055%~0.065%, N≤0.0035%, H≤0.00012%, P≤0.015%, S≤0.0020%, Ce≥5ppm, with the remainder being Fe and unavoidable impurities. The sum of the above components is 100%.
3. The low crack sensitivity ultra-high grade wear-resistant steel plate according to claim 1, characterized in that: Its chemical composition by mass percentage is as follows: C: 0.30%–0.35%, Si: 0.15%–0.25%, Mn: 0.3%–0.45%, Nb: 0.030%–0.045%, Mo: 0.001%–0.50%, Ni: 0.001%–0.30%, V: 0.035%–0.045%, Ti: 0.002%–0.004%, Cr: 1.2%–1.4%, B: 0.0008%–0.0015%, Alt: 0.055%–0.065%, N≤0.0035%, H≤0.00012%, P≤0.015%, S≤0.0020%, Ce≥5ppm, with the remainder being Fe and unavoidable impurities. The sum of all the above components is 100%.
4. The low crack sensitivity ultra-high grade wear-resistant steel plate according to claim 1, characterized in that: Its chemical composition by mass percentage is as follows: C: 0.43%–0.45%, Si: 0.15%–0.25%, Mn: 0.30%–0.45%, Nb: 0.035%–0.055%, Mo: 0.001%–0.50%, Ni: 0.001%–0.30%, V: 0.035%–0.045%, Ti: 0.002%–0.004%, Cr: 1.2%–1.4%, B: 0.0006%–0.0015%, Alt: 0.055%–0.065%, N≤0.0035%, H≤0.00012%, P≤0.015%, S≤0.0020%, Ce≥5ppm, with the remainder being Fe and unavoidable impurities. The sum of all the above components is 100%.
5. A method for preparing a low-crack-sensitivity ultra-high-grade wear-resistant steel plate as described in any one of claims 1-4, characterized in that, The process is as follows: hot metal desulfurization pretreatment - converter smelting - LF+RH refining - continuous casting - billet cooling - billet acceptance - billet heating - descaling - rolling - steel plate cooling - flaw detection - preheat treatment - shot blasting - quenching - tempering - straightening - cutting and sampling - marking - inspection - warehousing, among which: During the rolling process, the thickness of the heated billet is controlled to be (1.5~3)*h, where h is the thickness of the finished steel plate in mm, and the final rolling temperature is ≤ the quenching temperature. After rolling, the steel plate is slowly cooled in a heated insulation pit. The slow cooling time is in hours and is set according to the thickness of the steel plate as (10~20) * h, where h is the finished thickness of the steel plate in cm. Before offline quenching, preheating treatment is performed at a temperature between 500 and 800℃. The heat treatment time is in minutes and is calculated as (4 to 10) * h, where h is the thickness of the finished steel plate in mm.
6. The method for preparing ultra-high wear-resistant steel plate with low crack sensitivity according to claim 5, characterized in that: The mass fraction of sulfur in the molten iron after desulfurization pretreatment and slag removal is ≤0.0025%.
7. The method for preparing ultra-high wear-resistant steel plate with low crack sensitivity according to claim 5, characterized in that: During the steel tapping process in the converter, 50-200 kg of 5%-40% rare earth cerium-iron alloy is added.
8. The method for preparing ultra-high wear-resistant steel plate with low crack sensitivity according to claim 5, characterized in that: The tundish baking time during the continuous casting process is ≥5 hours.
9. The method for preparing ultra-high wear-resistant steel plate with low crack sensitivity according to claim 5, characterized in that: The quenching temperature is 830–930℃, and the tempering temperature is 120–220℃.
10. The method for preparing ultra-high wear-resistant steel plate with low crack sensitivity according to claim 5, characterized in that: The prepared steel plate has a Brinell hardness of 500HB to 620HB and a strength of 1500 to 2300 MPa. The crack incidence rate of the steel plate during the cutting process is ≤1%.