Wear-resistant steel resistant to high-mineralization coal mine water corrosion and preparation method thereof

Abstract

The present invention discloses a wear-resistant steel resistant to high-mineralization coal mine water corrosion and a preparation method thereof. The wear-resistant steel effectively enhances the wear-resistant steel's ability to resist high-mineralization coal mine water corrosion by composite addition of Cr, Cu, Ni, and Sb, thereby improving the wear-resistant steel's ability to resist corrosion and wear in high-mineralization coal mine working conditions. The relative wear resistance is 1.21 to 1.29 times that of low-alloy wear-resistant steel of the same hardness level. The problem of cracks in the Sb-containing wear-resistant steel during the production process is effectively suppressed. Furthermore, by composite addition of V and Mo and in conjunction with a heat treatment heating path design, a large amount of V and Mo composite carbides are retained in the tempered steel plate, and these carbides serve as hydrogen traps, thereby significantly improving the ability of the Sb-containing wear-resistant steel to resist hydrogen-induced cracking during service, thereby obtaining a wear-resistant steel resistant to high-mineralization coal mine water corrosion and wear with excellent mechanical properties and resistance to hydrogen-induced cracking.

Description

Technical Field

[0001] The present invention relates to the field of metal materials, in particular to wear-resistant steel resistant to corrosion by high-mineralization coal mine water and a preparation method thereof. Background Art

[0002] Low-alloy wear-resistant steel, with its excellent comprehensive properties, is widely used in mining, mineral processing, metallurgy, chemical engineering, and transportation. As a consumable material, its lifespan depends not only on the wear intensity of the operating conditions, but is also strongly affected by the corrosive environment of the operating conditions. Scraper conveyors are the primary equipment for coal mining and transportation. During their service underground in coal mines, they are subjected to high-intensity wear from coal, gangue, and other materials for long periods of time. The plates and bottom plates are primarily made of low-alloy wear-resistant steel. At the same time, the corrosion caused by coal mine water on the wear-resistant steel is extremely severe, which can change the service conditions of the wear-resistant steel from a single wear condition to a corrosive wear condition, exacerbating the wear of the wear-resistant steel. Therefore, it is necessary to develop corrosion-resistant and wear-resistant steel plates specifically for the mining environment, reduce the loss of wear-resistant steel, and extend the service life of wear-resistant steel and related equipment.

[0003] Publication No. CN114774772A discloses a corrosion-resistant 500HB martensitic wear-resistant steel plate. Although the corrosion resistance of the wear-resistant steel plate is significantly enhanced, the alloy cost is high due to the addition of a large amount of Ni, Cr and Mo elements.

[0004] Publication number CN110387507B discloses an HB500-grade wear-resistant steel for corrosive slurry transport containers. The patent document does not confirm the corrosion or abrasion resistance through experiments, and its manufacturing process includes online quenching, cooling from no less than 825°C to room temperature at a cooling rate of 55-65°C / s. This process is not conducive to controlling internal cracks in high-grade wear-resistant steel plates.

[0005] Publication No. CN112267073A discloses a corrosion-resistant wear steel plate with excellent low-temperature toughness and welding performance. The corrosion resistance of the steel is enhanced by adding Sb and Sn elements, but it does not take into account that Sb and Sn elements will also increase the risk of cracking in the wear-resistant steel. In addition, there is no corresponding technology to alleviate or avoid the negative effects of Sb and Sn elements on cracking in the wear-resistant steel. At the same time, the corrosion resistance or wear resistance effect has not been clarified through experiments.

[0006] Publication No. CN112159934A discloses a corrosion-resistant and wear-resistant steel plate, which adds a large amount of Cr element to ensure corrosion resistance in acidic environments. However, this will greatly increase the alloy cost of the steel and significantly deteriorate the welding performance of the steel, which is not conducive to promotion and application.

[0007] Publication No. CN112195405B discloses an economical corrosion-resistant and wear-resistant steel and a preparation method thereof. The steel has high contents of C and P and has a high risk of cracking during both the manufacturing and application processes.

[0008] In summary, corrosion-resistant and wear-resistant steels currently achieve corrosion resistance primarily through the addition of large amounts of alloying elements such as Cr, Ni, and Mo. However, this increases the cost of the steel plate and is detrimental to welding. While Sb and Sn can mitigate these cost and weldability issues, their addition to wear-resistant steel, which is highly crack-sensitive, dramatically increases the risk of cracking, particularly in wear-resistant steel used in coal mine scraper conveyors, where cracks can cause significant losses. Summary of the Invention

[0009] In view of this, the present disclosure provides a method for preparing wear-resistant steel resistant to corrosion by highly mineralized coal mine water, which effectively solves the problem that the current method mainly achieves corrosion resistance by adding a large amount of alloying elements such as Cr, Ni and Mo, but this will increase the cost of the steel plate and is not conducive to the welding of the steel plate. Even if the cost and weldability problems can be avoided by adding Sb and Sn, since Sb and Sn are low-melting-point elements, when added to wear-resistant steel with strong crack sensitivity, there is a sharp increase in the risk of cracks, especially for wear-resistant steel used in coal mine scraper conveyors, where cracks in the steel plate will cause great losses.

[0010] In addition, the present disclosure also provides wear-resistant steel produced by the above-mentioned preparation method, which has good corrosion and wear resistance under high-mineralization coal mine water conditions, and ensures that the steel plate does not crack during the manufacturing process, and has strong resistance to delayed cracking during service.

[0011] In the first aspect, the preparation method of the wear-resistant steel resistant to high-mineralization coal mine water corrosion, the chemical composition of the wear-resistant steel is as follows, calculated by weight percentage:

[0012] C: 0.18%~0.35%, Si: 0.15%~0.50%, Mn: 0.30%~0.80%, P: ≤0.015%, S: ≤0.003%, Cr: 2.20%~3.60%, Cu: 0.20%~0.60%, Ni: 0.10%~0.40%, Mo: 0.10%~0.55%, Sb: 0.06%~0.10%, V: 0.03%~0.08%, Ti: 0.006%-0.018%, Als: 0.015%-0.05%, B: 0.0008%~0.0016%, and the balance is Fe and unavoidable impurities.

[0013] In the present disclosure and possible embodiments, the method includes the steps of slow cooling of the continuous casting billet, heating, rolling, slow cooling of the steel plate and heat treatment, wherein:

[0014] During the slow cooling and heating process of the continuous casting billet, the continuous casting billet enters a slow cooling pit with a heating function or a heating furnace for heating and slow cooling. When the slow cooling starts, the temperature of the continuous casting billet is ≥450°C, the continuous casting billet is heated to 520°C~580°C and kept warm for 24h~36h, and then the heating is stopped. The continuous casting billet is cooled in the slow cooling pit or the heating furnace for 24h~36h; after slow cooling, the continuous casting billet is sent to the heating furnace, the furnace entry temperature is ≥300°C, the heating temperature is 1100°C~1200°C, and the continuous casting billet time in the furnace is 0.45~0.7min / mm.

[0015] In the present disclosure and possible embodiments, in the rolling process, the starting rolling temperature is 950°C to 1050°C, and the finishing rolling temperature is 820°C to 1050°C.

[0016] In the present disclosure and possible embodiments, in the steel plate slow cooling process, the rolled steel plates are stacked and slowly cooled offline, the stacked slowly cooled steel plate temperature is 300°C≤580°C, and the temperature is slowly cooled to ≤150°C.

[0017] In the present disclosure and possible embodiments, the heat treatment process is divided into quenching treatment and tempering treatment. The quenching heat treatment furnace for the quenching treatment is provided with a high temperature section and a cooling section. The temperature of the high temperature section is 860°C to 920°C, and the time of the high temperature section in the furnace is 14 min / mm to 2.0 min / mm; the temperature of the cooling section is 750°C to 790°C, and the time of the cooling section in the furnace is 0.5 min / mm to 1.0 min / mm; the steel plate coming out of the quenching heat treatment furnace enters a roller quenching machine for quenching, the average cooling rate of quenching is 9°C to 52°C / s, and the final quenching temperature is 120°C to 280°C.

[0018] In the present disclosure and possible embodiments, in the tempering treatment process, the tempering heat treatment furnace is set to a high temperature section and a low temperature section, the temperature of the high temperature section is 360°C to 440°C, and the time of the high temperature section in the furnace is 1.6 min / mm to 2.4 min / mm; the temperature of the low temperature section is 220°C to 260°C, and the time of the low temperature section in the furnace is 2.4 min / mm to 3.6 min / mm.

[0019] In the second aspect, the wear-resistant steel resistant to corrosion by high-mineralization coal mine water is produced by the method described in the first aspect.

[0020] The present invention has the following beneficial effects:

[0021] (1) The wear-resistant steel of the present invention effectively enhances the corrosion resistance of the wear-resistant steel to high-mineralization coal mine water by the composite addition of Cr-Cu-Ni-Sb, and improves the corrosion and wear resistance of the wear-resistant steel in high-mineralization coal mine working conditions. The relative wear resistance is 1.21 to 1.29 times that of low-alloy wear-resistant steel of the same hardness level.

[0022] (2) The present invention effectively suppresses the problem of cracks in Sb-containing wear-resistant steel during the production process through process design, and through the composite addition of V and Mo, combined with the design of the heat treatment heating path, a large amount of V and Mo composite carbides are retained in the tempered steel plate, and used as hydrogen traps, thereby greatly improving the ability of Sb-containing wear-resistant steel to resist hydrogen-induced cracks during service, and obtaining a wear-resistant steel with excellent mechanical properties, resistance to hydrogen-induced cracks, and resistance to corrosion and wear of high-mineralized coal mine water. DETAILED DESCRIPTION

[0023] The present disclosure is described below based on examples, but it is worth noting that the present disclosure is not limited to these examples. In the detailed description of the present disclosure below, some specific details are described in detail. However, for the parts that are not described in detail, those skilled in the art can also fully understand the present disclosure. At the same time, unless the context clearly requires otherwise, the words "including", "comprising" and similar words throughout the specification and claims should be interpreted as including rather than exclusive or exhaustive; that is, as "including but not limited to".

[0024] The present disclosure describes in detail the wear-resistant steel resistant to high-mineralization coal mine water corrosion and its preparation method through Examples 1-15, wherein the chemical composition and weight percentage of the wear-resistant steel are as follows:

[0025] C: 0.18~0.35%, Si: 0.15~0.50%, Mn: 0.30~0.80%, P: ≤0.015%, S: ≤0.003%, Cr: 2.20~3.60%, Cu: 0.20~0.60%, Ni: 0.10~0.40%, Mo: 0.10~0.55%, Sb: 0.06~0.10%, V: 0.03~0.08%, Ti: 0.006-0.018%, Als: 0.015-0.05%, B: 0.0008~0.0016%, and the balance is Fe and unavoidable impurities.

[0026] The above alloying element types and contents are selected in the embodiments of the present disclosure because:

[0027] C: It is the main element that determines the strength and hardness of wear-resistant steel. With the increase of carbon, the supersaturated martensite deformation becomes more severe, the strength and hardness become higher, but at the same time the brittleness increases. In order to match the strength and hardness reduction brought about by subsequent heat treatment, the range is controlled at 0.18~0.35%.

[0028] Si: It is a solid solution strengthening element and a strong deoxidizing element. It can improve the strength and hardness of steel. However, excessive addition will reduce the plasticity and toughness of the steel plate and aggravate the surface decarburization of the steel. The range is controlled within 0.15-0.5%.

[0029] Mn: It is a solid solution strengthening element that can improve the strength of steel. However, too high a Mn content will aggravate the segregation of the steel billet and cause crack initiation. In order to reduce the risk of cracks, the range is controlled between 0.3 and 0.8%.

[0030] P and S: are inevitable impurities in steel, and the range of P is controlled to be ≤ 0.015% and S ≤ 0.003%.

[0031] Cr: It is a solid solution strengthening element and also an element that improves the corrosion resistance of steel. For high mineralization coal water service environment, Cl in coal water - and SO4 2- The high ion content causes serious corrosion to the steel matrix, and the effect of corrosion on the loss of steel plates during the abrasion process of steel plates is greatly increased. Therefore, it is key to greatly improve the corrosion resistance of wear-resistant steel for service in high-mineralized coal-water wear-resistant steel. This requires that the steel plate quickly form a higher-density α-FeOOH rust layer. Cr can be enriched in large quantities in the matrix cross-section, which is conducive to the formation of the FeOOH rust layer, and as the Cr content increases, the Cr enrichment rate and content increase, the FeOOH rust layer formation rate accelerates, and the corrosion resistance of the steel is significantly enhanced. In addition, Cr and C can form fine precipitates to enhance the wear resistance of steel. The composite addition of Cr and Mo can effectively enhance the hardenability of the steel plate and increase the hardening layer of steel. It is an alloying element that effectively improves the corrosion and wear resistance of steel. The range is controlled at 2.20~3.60%.

[0032] Cu: It is an element that improves the corrosion resistance of steel to high mineralization. When added together with Cr, it can make the FeOOH rust layer denser and inhibit the diffusion of Cl- and SO42- into the steel matrix. However, excessive addition of Cu will increase the crack risk of the steel plate. The range is controlled at 0.20~0.60%.

[0033] Ni: It is an element that improves the corrosion resistance of steel to high mineralization. It is also easy to be enriched at the interface with the matrix. The Ni in the FeOOH rust layer has a significant effect on inhibiting the diffusion of Cl- into the steel matrix. At the same time, Ni can improve the toughness of steel and inhibit the surface cracks of the steel plate caused by Cu addition. At the same time, Ni is a grain boundary segregation element, which enhances the grain boundary strength, improves the crack resistance of steel, and can reduce the phase transition temperature of steel. However, due to the high price of Ni, the range is controlled at 0.1~0.4%.

[0034] Mo: Mo delays ferrite transformation and is an effective element for improving steel hardenability. It increases the depth of the hardened layer and improves wear resistance. Mo is also a strong carbide-forming element. Its addition in combination with V promotes the precipitation of V-Mo composite carbides, enhancing the precipitation effect. Mo content is controlled within the range of 0.10-0.55%.

[0035] Sb: It densifies corrosion products, inhibits the diffusion of H2O, O2, Cl-, and SO42- into the steel matrix, and accumulates near the steel matrix in highly mineralized environments, where it reacts with the concentrated Cu to form Cu2Sb, which is insoluble in alkali and resists further corrosion of the steel matrix. However, Sb is a low-melting-point element and tends to accumulate at grain boundaries, causing grain boundary cracks. The risk of steel plate cracking increases rapidly with increasing Sb content, but should be kept within a range of 0.06 to 0.10%.

[0036] V: is a strong carbide-forming element that can precipitate during heat treatment and form a hydrogen trap when combined with Mo, effectively fixing free H in the steel and preventing H from gathering at the crack source and causing delayed cracking. It is the key technology for the crack resistance of the wear-resistant steel of the present invention and is controlled within a range of 0.03 to 0.08%.

[0037] Ti: It can form TiN with N. TiN has high temperature stability. On the one hand, it inhibits the growth of austenite during the heating process of steel, and on the other hand, it reduces the solid solution N. Both of these effects can increase the toughness of steel. When the Ti content is too high, the number of large particle inclusions in the steel will increase significantly. The range is controlled within 0.45% to 0.55%.

[0038] Als: It is a strong deoxidizing element, and its content is controlled within the range of 0.015% to 0.045%.

[0039] B: It can delay the ferrite phase transformation and is an effective element for improving the hardenability of steel. However, it tends to concentrate at the grain boundaries. When the B content is too high, it will precipitate at the grain boundaries, reducing the grain boundary strength and worsening the toughness of the steel. The range is controlled within 0.0008-0.0016%.

[0040] The chemical composition of the wear-resistant steel of Examples 1-15 of the present disclosure is shown in Table 1:

[0041] Table 1 Chemical composition of example steel (wt%)

[0042] C Si Mn P S Cr Cu Ni Mo V Sb Ti Als B Example 1 0.14 0.25 0.80 0.0127 0.0018 2.88 0.33 0.28 0.3 0.06 0.03 0.012 0.048 0.0015 Example 2 0.13 0.5 0.68 0.0107 0.0021 2.44 0.23 0.22 0.45 0.06 0.06 0.007 0.046 0.0012 Example 3 0.16 0.2 0.77 0.0134 0.0022 2.20 0.3 0.13 0.31 0.07 0.03 0.018 0.047 0.0009 Example 4 0.17 0.31 0.54 0.0083 0.0021 3.24 0.48 0.27 0.26 0.09 0.04 0.009 0.029 0.0014 Example 5 0.2 0.47 0.51 0.0093 0.0027 2.80 0.33 0.25 0.17 0.06 0.02 0.007 0.016 0.001 Example 6 0.21 0.4 0.46 0.0125 0.0018 3.11 0.34 0.32 0.5 0.08 0.06 0.015 0.05 0.0008 Example 7 0.21 0.29 0.33 0.0139 0.0029 2.33 0.35 0.22 0.37 0.06 0.07 0.015 0.031 0.001 Example 8 0.23 0.36 0.49 0.0105 0.0028 2.65 0.54 0.28 0.1 0.04 0.04 0.015 0.019 0.0008 Example 9 0.23 0.2 0.53 0.0138 0.0016 2.78 0.53 0.4 0.17 0.03 0.04 0.012 0.037 0.0014 Example 10 0.26 0.47 0.65 0.0136 0.0019 3.53 0.41 0.16 0.33 0.06 0.05 0.006 0.025 0.001 Example 11 0.27 0.17 0.68 0.0136 0.0028 2.83 0.52 0.12 0.53 0.08 0.03 0.018 0.027 0.0008 Example 12 0.27 0.2 0.30 0.015 0.0016 3.60 0.45 0.12 0.32 0.06 0.02 0.012 0.037 0.0016 Example 13 0.28 0.2 0.47 0.0093 0.0015 2.71 0.47 0.35 0.29 0.07 0.08 0.01 0.031 0.0015 Example 14 0.29 0.37 0.66 0.011 0.0019 2.56 0.58 0.31 0.12 0.08 0.02 0.008 0.033 0.0012 Example 15 0.30 0.45 0.54 0.0084 0.0028 3.25 0.58 0.35 0.54 0.06 0.07 0.009 0.048 0.0016

[0043] In Examples 1-15 of the present disclosure, wear-resistant steel was prepared according to the chemical composition and content designed in Table 1. The specific process route was: molten iron pretreatment, converter steelmaking, LF furnace refining, RH vacuum degassing, continuous casting, slow cooling of the continuous casting, heating, rolling, slow cooling of the steel plate, and heat treatment, wherein:

[0044] For the slow cooling and heating process of continuous casting billets, the continuous casting billets enter the slow cooling pit or heating furnace with heating function for heating and slow cooling. The temperature of the continuous casting billets at the beginning of slow cooling is ≥450℃. The continuous casting billets are heated to 520-580℃ and kept warm for 24-36h. Then the heating is stopped and the continuous casting billets are slowly cooled in the slow cooling pit or heating furnace for 24h-36h.

[0045] After slow cooling, the continuous casting slab is sent to a heating furnace with an entry temperature of ≥300°C, a heating temperature of 1100-1200°C, and a furnace time of 0.45-0.7 min / mm. The slow cooling and heating process parameters of the continuous casting slabs of Examples 1-15 of the present disclosure are shown in Table 2 below:

[0046] Table 2 Slow cooling and heating process of continuous casting slab in Example

[0047]

[0048] During the rolling and slow cooling process, the starting rolling temperature is 950-1050°C, and the final rolling temperature is 820-1050°C. After rolling, the steel plates are quickly stacked and slowly cooled. The stacking slow cooling steel plate temperature is 300°C ≤ 580°C, and then slowly cooled to ≤ 150°C. The rolling and slow cooling process parameters of Examples 1-15 of the present disclosure are shown in Table 3 below:

[0049] Table 3 Rolling and slow cooling process of example steel

[0050]

[0051] The heat treatment process of the disclosed embodiments includes quenching and tempering, wherein the steel plate quenching heating includes a high temperature section and a cooling section. The high temperature section is 860-920°C, with a furnace time of 14-2.0 min / min; the cooling section is 750-790°C, with a furnace time of 0.5-1.0 min / min. The quenching heating process parameters of Examples 1-15 of the disclosed embodiments are shown in Table 4 below:

[0052] Table 4 Quenching and heating process of example steel

[0053]

[0054] After leaving the quenching heat treatment furnace, the steel plates are quenched in a roller quenching machine. The average cooling rate during quenching is 9-52°C / s, and the final quenching temperature is 120-280°C.

[0055] The tempering heating of the steel plate includes a high temperature section and a low temperature section. The high temperature section of the tempering heat treatment furnace is 360-440°C, and the high temperature section is in the furnace for 1.6-2.4 min / min; the low temperature section is 220-260°C, and the low temperature section is in the furnace for 2.4-3.6 min / min. The quenching cooling and tempering process parameters of Examples 1-15 of the present disclosure are shown in Table 5:

[0056] Table 5 Quenching, cooling and tempering process of example steel

[0057]

[0058]

[0059] For the preparation method disclosed herein, the parameters selected in the above steps are as follows:

[0060] Delayed cracking in wear-resistant steel is closely related to the hydrogen content and its state. The basic requirement for avoiding delayed cracking during use is that the hydrogen content in the steel is low and that the heating and slow cooling of the billet can fully release hydrogen. Among them, the purpose of adopting a furnace entry temperature of ≥450°C in this disclosure is to avoid the billet temperature being too low, which will cause hydrogen to segregate and accumulate in inclusions in the billet, resulting in cracks; the billet is heated to 520-580°C because the solid solubility of hydrogen in the ferrite phase is low and the hydrogen diffusion rate is fast at higher temperatures. At the same time, considering that Sb has a low melting point and is prone to enrichment at grain boundaries and cracks, the heating temperature should not be too high; when hydrogen is reduced to a certain level, the diffusion efficiency decreases, and the risk of hydrogen-induced cracking in the billet has been eliminated. In order to balance production efficiency and billet quality, the holding time is controlled to 24-36 hours, and then heating is stopped and the billet is slowly cooled in a slow cooling pit or heating furnace for 24-36 hours.

[0061] Because Sb is a low-melting-point element and easily accumulates at grain boundaries, causing cracks in steel billets and rolled steel plates, the preparation method disclosed herein requires low-temperature steel sintering, with a heating temperature of 1100-1200°C. At the same time, a hot delivery process is adopted, with the billet entering the furnace at a temperature ≥300°C, shortening the heating time. The billet stays in the furnace for 0.45-0.7 min / mm.

[0062] Hot rolling is used to recrystallize the austenite of the steel, making the austenite grains uniform and coarse before quenching. This is because the grain boundaries are more sensitive to high mineralization corrosion and have a high corrosion rate. Therefore, in order to avoid excessive grain boundary content and excessive grain refinement, the starting rolling temperature is 950-1050℃ and the finishing rolling temperature is 820-1050℃.

[0063] Because the steel plate is in a high temperature state after rolling and the thickness specification is reduced, rapid off-line stacking and slow cooling are conducive to the re-diffusion of hydrogen, reducing the H content in the steel plate and inhibiting the occurrence of hydrogen-induced cracks in the steel plate. In order to avoid the risk of cracks caused by Sb enrichment, the stacking steel plate temperature is 300℃≤≤580℃; to balance production efficiency, the steel plate is designed to be slowly cooled to ≤150℃ before entering the next production process.

[0064] Heat treatment includes quenching and tempering, and steel plate quenching heating includes high temperature section and cooling section. The temperature of the high temperature section of the quenching heat treatment furnace is 860-920℃, and the time in the high temperature section is 1.4-2.0min / mm. Its purpose is to quickly heat the steel plate to the austenitizing temperature to provide organizational guarantee for the subsequent quenching of the steel plate to obtain martensite. However, too high a temperature will lead to Sb enrichment at the grain boundaries, increase the risk of cracks, and increase the austenite grain size, reducing the low-temperature toughness of the steel plate. Therefore, the holding time should not exceed 1.4min / mm; the temperature of the cooling section is 750-790℃, and the time in the cooling section is 0.5-1.0min / mm. Its purpose is to reduce the austenite to above the Ar3 temperature in the cooling section, that is, to ensure that the steel plate is fully austenitized and the quenched steel plate is fully hardened. At the same time, the lower the starting quenching temperature of the steel plate, the lower the stress level of the steel plate during the quenching process, avoiding cracking of the wear-resistant steel due to the quenching process. At the same time, the design of the steel plate holding time takes into account the influence of the steel plate's uniform heat and Sb-induced cracks.

[0065] After the steel plate leaves the quenching heat treatment furnace, it enters the roller quenching machine for quenching. In order to obtain sufficient martensitic transformation and avoid excessive stress in the steel plate caused by excessive cooling rate and the occurrence of quenching cracks, the average quenching cooling rate is designed to be 9-52℃ / s; the quenching end temperature is limited to 180-280℃, with the aim of reducing the stress of the steel plate during the quenching process and avoiding quenching cracks. At the same time, it should be ensured that the austenite of the steel plate can fully complete the martensitic transformation.

[0066] Tempering heating of steel plates consists of two stages: a high-temperature stage and a low-temperature stage. The high-temperature stage is performed at a temperature of 360-440°C, with a furnace time of 1.6-2.4 min / mm. This stage aims to, on the one hand, continue to promote the outward diffusion of hydrogen from the steel plate, reducing its hydrogen content, and, on the other hand, promote the nucleation of a large number of V and Mo composite carbides through high temperature. These carbides will provide a large number of hydrogen traps within the steel plate. Considering that excessively high temperatures can reduce strength and hardness, the high-temperature stage temperature does not exceed 440°C. The low-temperature stage is performed at a temperature of 200-260°C, with a furnace time of 2.4-3.6 min / mm. This stage aims to build on the nucleation in the high-temperature stage by slowly allowing carbon to diffuse, causing the V and Mo composite carbides to grow, and improving hydrogen capture capacity.

[0067] The wear-resistant steels prepared in Examples 1-15 of the present disclosure were subjected to mechanical property tests. The specific test results are shown in Table 6 below:

[0068] Table 6 Mechanical properties of example steel

[0069]

[0070]

[0071] Wear tests were conducted on the test steels of Examples 1, 2, 4, 5, 13, and 15. Common low-alloy wear-resistant steels NM400, NM450, and NM500 with a thickness of 20 mm were selected as comparative examples. The wear test equipment was a wet rubber wheel abrasive wear tester. The wear specimen dimensions and test method were in accordance with ASTM G65. The SiC sand particle size was 80-120 mesh. The solvent was a simulated high-mineralization coal mine water solution, the chemical composition of which is shown in Table 7. The test force was 120 kN, the rotation speed was 200 r / min, and the wear time was 10 min. The mechanical properties of the comparative steels are shown in Table 8, and the wear test results are shown in Table 9.

[0072] Table 7 Main chemical composition of simulated acid mine water (mg / L)

[0073] <![CDATA[Cl - ]]> <![CDATA[SO4 2- ]]> <![CDATA[Na + ]]> <![CDATA[Ca 2+ ]]> <![CDATA[Mg 2+ ]]> pH 2256.3 1639.8 2517.3 2612.4 569.1 7

[0074] Table 8 Mechanical properties of comparative steel

[0075]

[0076] Table 9 Corrosion and wear test results

[0077]

[0078] According to Tables 6, 8 and 9, it can be seen that Examples 1 and 2 and Comparative Example 1 are both made of NM400 wear-resistant steel, and their mechanical properties are comparable, but Examples 1 and 2 are 1.27 and 1.29 times the relative wear resistance of Comparative Example 1; Examples 4 and 5 and Comparative Example 2 are both made of NM450 wear-resistant steel, and their mechanical properties are comparable, but Examples 4 and 5 are 1.21 and 1.22 times the relative wear resistance of Comparative Example 2; Examples 13 and 15 and Comparative Example 3 are both made of NM500 wear-resistant steel, and their mechanical properties are comparable, but Examples 13 and 15 are 1.23 and 1.24 times the relative wear resistance of Comparative Example 3; In summary, the wear-resistant steel manufactured according to the method of the present invention has better wear resistance under simulated high-mineralization coal mine water conditions.

[0079] The above-described embodiments are merely examples of implementation methods of the present disclosure, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art may make various modifications, equivalent substitutions, and improvements without departing from the scope of the present disclosure, and these modifications are all within the scope of protection of the present disclosure. Therefore, the scope of protection of the present invention shall be based on the appended claims.

Claims

1. A method for preparing wear-resistant steel resistant to corrosion by high-mineralization coal mine water, characterized in that: The chemical composition of the wear-resistant steel is as follows: C: 0.18% to 0.35%, Si: 0.15% to 0.50%, Mn: 0.30% to 0.80%, P: ≤0.015%, S: ≤0.003%, Cr: 2.20% to 3.60%, Cu: 0.20% to 0.60%, Ni: 0.10% to 0.40%, Mo: 0.10% to 0.55%, Sb: 0.06% to 0.10%, V: 0.03% to 0.08%, Ti: 0.006%-0.018%, Als: 0.015%-0.05%, B: 0.0008% to 0.0016%, the balance is Fe and unavoidable impurities; The method for preparing wear-resistant steel includes the steps of slow cooling, heating, rolling, slow cooling of steel plates, and heat treatment of continuous casting billets. During the slow cooling and heating steps, the continuous casting billets enter a slow cooling pit with a heating function or a heating furnace for heating and slow cooling. The temperature of the continuous casting billets is initially ≥450°C, and the continuous casting billets are heated to 520°C to 580°C and kept warm for 24 to 36 hours. Subsequently, heating is stopped, and the continuous casting billets are cooled in the slow cooling pit or the heating furnace for 24 to 36 hours. The heat treatment process is divided into quenching and tempering. The quenching heat treatment furnace for the quenching treatment is provided with a high temperature section and a cooling section. The temperature of the high temperature section is 860°C to 920°C, and the time of the high temperature section in the furnace is 14 min / mm to 2.0 min / mm; the temperature of the cooling section is 750°C to 790°C, and the time of the cooling section in the furnace is 0.5 min / mm to 1.0 min / mm. The steel plate coming out of the quenching heat treatment furnace enters a roller quenching machine for quenching. The average cooling rate of quenching is set to 9°C to 52°C / s, and the final quenching temperature is 120°C to 280°C. In the tempering treatment process, the tempering heat treatment furnace is set to a high temperature section and a low temperature section. The temperature of the high temperature section is 360°C to 440°C, and the time in the high temperature section in the furnace is 1.6 min / mm to 2.4 min / mm; the temperature of the low temperature section is 220°C to 260°C, and the time in the low temperature section in the furnace is 2.4 min / mm to 3.6 min / mm.

2. The method for preparing wear-resistant steel according to claim 1, characterized in that: The continuous casting billet is slowly cooled and then sent to a heating furnace, the furnace entry temperature is ≥300°C, the heating temperature is 1100°C to 1200°C, and the continuous casting billet is kept in the furnace for 0.45 to 0.7 min / mm.

3. The method for preparing wear-resistant steel according to claim 2, characterized in that: In the rolling process, the starting rolling temperature is 950°C to 1050°C, and the finishing rolling temperature is 820°C to 1050°C.

4. The method for preparing wear-resistant steel according to claim 3, characterized in that: In the steel plate slow cooling process, the rolled steel plates are stacked and slowly cooled offline, the temperature of the stacked and slowly cooled steel plates is 300°C≤580°C, and the temperature is slowly cooled to ≤150°C.

5. A wear-resistant steel resistant to corrosion in highly mineralized coal mine water, characterized by: The method is prepared by any one of claims 1 to 4.

Images