1100MPa-grade corrosion-resistant steel plate as well as preparation method and application thereof

Abstract

The invention provides a 1100MPa-grade corrosion-resistant steel plate, a preparation method and application, and the 1100MPa-grade corrosion-resistant steel plate comprises the following chemical components in percentage by mass: 0.15 to 0.21 percent of C, 0.06 to 0.10 percent of Si, 1.30 to 1.80 percent of Mn, 0.50 to 0.80 percent of Cr, 0.20 to 0.30 percent of Mo, 0.002 to 0.005 percent of B, less than or equal to 0.015 percent of P, less than or equal to 0.005 percent of S, 0.04 to 0.09 percent of Nb, V and Ti, and the balance of Fe and other inevitable impurities. The structure of the steel plate is tempered martensite, the yield strength is larger than or equal to 1150 MPa, the tensile strength is larger than or equal to 1350 MPa, and the impact energy at the temperature of minus 40 DEG C is larger than The process method disclosed by the invention is simple and convenient to operate, and the prepared 1100MPa-grade corrosion-resistant steel plate has wide applicability.

Description

Technical Field

[0001] The present invention belongs to the technical field of advanced steel material manufacturing, and in particular relates to an 1100MPa-grade corrosion-resistant steel plate, a preparation method and an application thereof. Background Art

[0002] Engineering machinery, ships, and oil and gas pipelines are often exposed to complex and harsh corrosive environments during their service life, which severely reduces their safety and service life. Currently, the corrosion problem of steel products is mainly addressed by applying protective coatings to the steel plates to isolate them from the corrosive media and mitigate the corrosion. However, protective coatings are prone to failure due to factors such as aging and external impact, resulting in direct contact between the steel products and the corrosive media. Therefore, the surface quality of the steel plate itself is closely related to its corrosion resistance.

[0003] While prior art has improved the corrosion resistance of steel through optimization of composition and ratios, the composition contains a high Si content. Si reacts with oxygen in the steel to form FeO / Fe2SiO4, which pins the steel to the surface and is difficult to completely remove, affecting the steel's corrosion resistance. Other reports have also reported improving the corrosion resistance of steel through cleaning pretreatment and surface fluorination protection, but this method has high coating costs and is difficult to promote and apply on a large scale. Based on this, the present application proposes an 1100 MPa-grade corrosion-resistant steel plate, a preparation method, and its application. Summary of the Invention

[0004] The main purpose of the present invention is to provide an 1100MPa grade corrosion-resistant steel plate, a preparation method and an application thereof, aiming to solve the technical problems of poor corrosion resistance and high cost of steel plates in the prior art.

[0005] To achieve the above objectives, the present invention provides an 1100 MPa corrosion-resistant steel plate. The chemical composition of the 1100 MPa corrosion-resistant steel plate, measured by mass fraction, includes: C 0.15-0.21%, Si 0.06-0.10%, Mn 1.30-1.80%, Cr 0.50-0.80%, Mo 0.20-0.30%, B 0.002-0.005%, P ≤ 0.015%, S ≤ 0.005%, Nb + V + Ti 0.04-0.09%, and the balance is Fe and other inevitable impurities.

[0006] The microstructure of the 1100MPa grade corrosion-resistant steel plate is tempered martensite, the yield strength is ≥1150MPa, the tensile strength is ≥1350MPa, and the impact energy at -40°C is ≥40J.

[0007] According to an embodiment of the present application, the 1100 MPa grade corrosion-resistant steel plate has a thickness of 10 to 30 mm and a width of 1800 to 4300 mm.

[0008] The application further provides a preparation method of the 1100MPa-grade corrosion-resistant steel plate, comprising the following steps: after the casting blank is sequentially subjected to heating, rough rolling, finish rolling, cooling, surface treatment, quenching and tempering, the 1100MPa-grade corrosion-resistant steel plate is obtained.

[0009] The chemical composition of the casting blank is the same as that of the 1100MPa-grade corrosion-resistant steel plate.

[0010] The temperature of the heating is 1200-1260℃, and the holding time is 30-50min.

[0011] The cooling is performed by three-stage cooling distributed along the running direction of the plate blank after the finish rolling, and the cooling water amount ratio of the first stage, the second stage and the third stage is (1.3-1.6):(1.2-1.4):1 in terms of volume ratio.

[0012] According to the embodiment of the application, the rough rolling temperature is 1100-1200℃, and the finish rolling temperature is 980-1050℃; the thickness of the intermediate blank after the rough rolling is 4-8 times of the target rolling thickness.

[0013] The rough rolling comprises 5-8 rolling passes, the single-pass reduction rate of at least three rolling passes is greater than or equal to 15%, and the single-pass reduction rate of at least one rolling pass is greater than or equal to 20%.

[0014] According to the embodiment of the application, the finish rolling temperature is 850-890℃, and the finish rolling temperature is 750-800℃.

[0015] The finish rolling comprises 7-11 rolling passes, and the single-pass reduction rate is 6-15%.

[0016] According to the embodiment of the application, the starting temperature of the cooling is 720-760℃, the cooling rate is 12-18℃ / s, and the re-red temperature is 450-500℃.

[0017] According to the embodiment of the application, the surface treatment adopts a high-speed shot blasting process.

[0018] The shot blasting amount is 950-1150kg / min, the shot blasting speed is 65-75m / s, and the dust removal air volume is 55000-65000m 3 / h.

[0019] According to the embodiment of the application, the quenching adopts a protective gas-water mist mixed quenching process.

[0020] The quenching temperature is 860-920℃, and the cooling rate is 15-30℃ / s.

[0021] The protective gas includes at least one of nitrogen, argon and carbon dioxide.

[0022] According to an embodiment of the present application, the tempering temperature is 250-300° C., and the tempering time is 60-120 minutes.

[0023] Application of the above-mentioned 1100 MPa corrosion-resistant steel plate or the 1100 MPa corrosion-resistant steel plate prepared by the above-mentioned preparation method in the field of engineering machinery.

[0024] The beneficial effects of the present invention are:

[0025] The 1100MPa-grade corrosion-resistant steel plate described in the present invention has a suitable chemical composition and content. The low Si content promotes the removal of iron oxide scale on the steel plate surface, while the high Cr content promotes the formation of a Cr-containing corrosion-resistant layer. Combined with process control, the resulting 1100MPa-grade corrosion-resistant steel plate has a tempered martensite structure, a yield strength of 1150MPa or greater, a tensile strength of 1350MPa or greater, and an impact energy of 40J or greater at -40°C. This effectively improves the surface quality and performance of the 1100MPa-grade corrosion-resistant steel plate.

[0026] The above-mentioned process method is simple, easy to operate, reduces production costs and energy consumption, and is suitable for large-scale industrial production. The 1100MPa-grade corrosion-resistant steel plate produced has a wide range of applicability and can effectively improve the corrosion resistance of steel plates in fields such as engineering machinery and oil and gas transportation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0028] Figure 1 This is a SEM image of the 1100 MPa corrosion-resistant steel plate of the present invention.

[0029] The realization of the objectives, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort fall within the protection scope of the present application.

[0031] In addition, the technical solutions among the various embodiments of the present application can be combined with each other, but it must be based on the fact that a person of ordinary skill in the art can realize the combination. When the combination of technical solutions appears to be contradictory or unachievable, it should be considered that the combination of technical solutions does not exist and is not within the protection scope of the present application.

[0032] To achieve the above object, the present application provides a 1100MPa-grade corrosion-resistant steel plate, the chemical composition of the 1100MPa-grade corrosion-resistant steel plate comprises, in mass fraction: C 0.15-0.21%, Si 0.06-0.10%, Mn 1.30-1.80%, Cr 0.50-0.80%, Mo 0.20-0.30%, B 0.002-0.005%, P≤0.015%, S≤0.005%, Nb+V+Ti 0.04-0.09%, and the balance is Fe and other inevitable impurities.

[0033] The 1100MPa-grade corrosion-resistant steel plate has a microstructure of tempered martensite, a yield strength of ≥1150MPa, a tensile strength of ≥1350MPa, and an impact energy at-40℃ of ≥40J.

[0034] In some embodiments, the chemical composition content of the 1100MPa-grade corrosion-resistant steel plate is regulated, such as Si content≤0.1%, Ni content≤0.25%, and Cr content≥0.5%. When the content of Si element is high, it will react with oxygen elements in the steel to form FeO / Fe2SiO4, which is pinned on the surface of the steel plate and is difficult to completely remove the oxide layer. Ni is easy to react with S element to generate low-melting-point NiS, which destroys the protective film generated by the steel plate under low-temperature conditions and accelerates surface oxidation. Therefore, the composition design with low Si and no Ni element can effectively remove the surface iron oxide scale, improve the surface quality of the steel plate, and reduce the corrosion rate. In combination with the addition of appropriate Cr element, the mechanical properties are ensured, and the formation of Cr-rich corrosion product layer during corrosion is promoted, thereby improving the corrosion resistance of the steel plate.

[0035] In some embodiments, in the chemical composition of the 1100MPa grade corrosion-resistant steel plate, chromium and molybdenum can form a dense oxide film on the surface of the steel plate, effectively preventing the invasion of corrosive media and improving corrosion resistance. Carbon and manganese elements can improve the strength of the steel plate. Silicon and titanium can refine the grains, improve and enhance the plasticity and toughness of the steel plate. Vanadium and niobium elements improve the wear resistance of steel by forming carbides and nitrides. The introduction of boron is conducive to obtaining a uniform structure. The corrosion resistance of the 1100MPa grade corrosion-resistant steel plate is improved by adding different alloying elements. The structure of the resulting steel plate is tempered martensite, and the tempered martensite structure is usually high in hardness and has good wear resistance. The yield strength is ≥1150MPa, the tensile strength is ≥1350MPa, and the impact energy at -40°C is ≥40J.

[0036] In some embodiments, the low-temperature impact energy at -40°C is ≥40J, so that the steel plate has good low-temperature toughness, that is, the steel plate can still absorb a large amount of energy without breaking in a low-temperature environment, and is suitable for mechanical parts working in a cold environment.

[0037] In some embodiments, the 1100 MPa corrosion-resistant steel plate has a thickness of 10 to 30 mm and a width of 1800 to 4300 mm.

[0038] In some embodiments, the 1100 MPa corrosion-resistant steel plate has a thickness of 20 mm and a width of 4000 mm.

[0039] In some embodiments, the thickness and width of the 1100 MPa corrosion-resistant steel plate are regulated to ensure that the quality of the steel plate meets production requirements. Therefore, the dimensions of the steel plate are not specifically limited. Optimizing the dimensions can reduce losses during the production process, improve material utilization, and reduce costs.

[0040] The aforementioned 1100MPa-grade corrosion-resistant steel plate has been optimized for its chemical composition and content. A low Si content promotes the removal of surface oxide scale, while a high Cr content promotes the formation of a Cr-containing corrosion-resistant layer. Combined with process control, the resulting 1100MPa-grade corrosion-resistant steel plate exhibits a tempered martensite structure, a yield strength ≥1150MPa, a tensile strength ≥1350MPa, and an impact energy ≥40J at -40°C. This effectively improves the surface quality and performance of the 1100MPa-grade corrosion-resistant steel plate.

[0041] The present invention also provides a method for preparing an 1100MPa corrosion-resistant steel plate, comprising the following steps: heating, rough rolling, finish rolling, cooling, surface treating, quenching and tempering the ingot in sequence to obtain the 1100MPa corrosion-resistant steel plate.

[0042] The chemical composition of the ingot is the same as that of the 1100MPa grade corrosion-resistant steel plate.

[0043] The heating temperature is 1200-1260° C., and the heat preservation time is 30-50 minutes.

[0044] The cooling adopts three-stage cooling distributed along the traveling direction of the slab after finish rolling. In terms of volume ratio, the cooling water volume ratio of the first stage: the second stage: the third stage is (1.3-1.6): (1.2-1.4): 1.

[0045] In some embodiments, the chemical composition of the cast steel sheet, by mass, includes: C 0.18%, Mn 1.60%, Mo 0.30%, Nb + V + Ti 0.08%, B 0.004%, Si 0.06%, Cr 0.8%, with the balance being Fe and unavoidable impurities. The cast steel sheet is heated at 1200-1260°C and held for 30-50 minutes. Thereafter, the steel sheet undergoes rough rolling, finish rolling, cooling, surface treatment, quenching, and tempering to produce an 1100 MPa corrosion-resistant steel sheet.

[0046] In some embodiments, the cooling is distributed along the traveling direction of the slab after finish rolling in three stages, and the amount of cooling water in each stage is controlled. Among them, the amount of cooling water in the first stage can cool quickly, which is conducive to efficient quenching of the steel plate to ensure the uniformity of the distribution of the mechanical properties of the steel plate and good strength. The amount of cooling water in the second stage is used to achieve medium-speed cooling as a transition. The amount of cooling water in the third stage is used for slow cooling, which is conducive to alleviating the residual stress of the steel plate during the cooling process, so that the steel plate has good plate shape and toughness. Through three-stage cooling, the reaction temperature of FeO eutectic can be avoided. At the same time, no pre-straightening after finish rolling can avoid the iron oxide from being pressed into the surface of the steel plate to form defects during straightening.

[0047] In some embodiments, the starting rolling temperature of the rough rolling is 1100-1200° C., and the finishing rolling temperature is 980-1050° C.; the thickness of the intermediate billet after the rough rolling is 4-8 times the target rolling thickness.

[0048] Wherein, the rough rolling includes 5 to 8 rolling passes; the single-pass reduction ratio of at least three rolling passes is ≥15%, and the single-pass reduction ratio of at least one rolling pass is ≥20%.

[0049] In some embodiments, the temperature of rough rolling is controlled so that the rough rolling is performed at a higher temperature, which reduces the resistance to rolling deformation and is beneficial for controlling the shape of the steel plate.

[0050] In some embodiments, the start rolling temperature of the finishing rolling is 850-890°C, and the final rolling temperature is 750-800°C.

[0051] The finishing rolling includes 7 to 11 rolling passes, and the reduction rate of each pass is 6 to 15%.

[0052] In some embodiments, finishing rolling is performed in a lower temperature range to avoid the intrusion of oxide scale caused by rolling in the high-temperature range. By regulating the finishing temperature, recrystallization during rolling is avoided, ensuring the steel plate maintains good plasticity during rolling. By controlling the number of rolling passes and the reduction ratio per pass, grain size can be refined and the material microstructure optimized. This helps achieve the desired size and shape of 1100 MPa corrosion-resistant steel plates.

[0053] In some embodiments, the cooling start temperature is 720-760°C, the cooling rate is 12-18°C / s, and the red-return temperature is 450-500°C. By regulating the cooling start temperature, uniform microstructure is maintained during the cooling process of the steel plate. Controlling the cooling rate promotes the transformation of the microstructure to high-hardness tempered martensite, significantly improving the hardness and wear resistance of the steel plate. Controlling the red-return temperature eliminates the internal stress generated by the tempered martensite transformation, reducing the brittleness of the steel plate and improving its toughness.

[0054] In some embodiments, the surface treatment is performed using a high-speed shot blasting process.

[0055] Among them, the shot blasting amount is 950~1150kg / min, the shot blasting speed is 65~75m / s, and the dust removal air volume is 55000~65000m 3 / h.

[0056] In some embodiments, the shot blasting amount is 1080-1120 kg / min, the shot blasting speed is 65-75 m / s, and the dust removal air volume is 55000-65000 m 3 / h. High-speed shot blasting effectively removes surface scale, rust, and burrs from steel plates, improving their surface condition. This method optimizes heating and cooling uniformity during the quenching process, reducing structural inhomogeneities and internal stress concentrations caused by local temperature differences. This improves plate shape issues such as warping and buckling that can occur during the quenching process, and enhances the dimensional stability and overall mechanical properties of the steel plates.

[0057] In some embodiments, the quenching is performed using a protective gas-water mist mixed quenching process.

[0058] The quenching temperature is 860-920°C, and the cooling rate is 15-30°C / s.

[0059] The protective gas includes at least one of nitrogen, argon and carbon dioxide.

[0060] In some embodiments, the quenching temperature is 875-885°C, the protective gas-water mist mixed quenching process dissipates heat evenly, and the cooling rate is precisely controlled, which is beneficial to the shape control of the steel plate. By mixing with the protective gas, the oxidation tendency of the steel plate surface is reduced, which is beneficial to improving the surface quality.

[0061] In some embodiments, the tempering temperature is 250-300° C. and the tempering time is 60-120 minutes. Tempering can reduce residual stress and reduce the risk of deformation and cracking during subsequent processing or service.

[0062] The above process is simple, easy to operate, reduces production costs and energy consumption, and is suitable for industrial large-scale production.

[0063] Application of the above-mentioned 1100 MPa corrosion-resistant steel plate or the 1100 MPa corrosion-resistant steel plate prepared by the above-mentioned preparation method in the field of engineering machinery.

[0064] The 1100MPa-grade corrosion-resistant steel plate produced by the above method has wide applicability and can effectively improve the corrosion resistance of steel plates in fields such as engineering machinery and oil and gas transportation.

[0065] For further understanding of the present invention, now give examples:

[0066] Example 1

[0067] The cast slab was heated at 1200°C and held at this temperature for 30 minutes. The chemical composition of the cast slab, by mass, was as follows: C 0.18%, Si 0.06%, Mn 1.60%, Cr 0.80%, Mo 0.30%, B 0.004%, P ≤ 0.015%, S ≤ 0.005%, Nb + V + Ti 0.08%, with the balance being Fe and other unavoidable impurities. After heating, rolling was performed, with the start temperature of rough rolling controlled at 1150°C and the finish temperature at 1000°C. The rough rolling process consisted of six passes, with two passes having a reduction ratio of 16% per pass and one pass having a reduction ratio of 20%. The intermediate slab thickness after rough rolling was 80 mm. The finish rolling process started at 860°C and ended at 760°C. The finish rolling process consisted of nine passes, with a reduction ratio of 12% per pass.

[0068] After rolling, a three-stage cooling process was carried out. The volume ratio of cooling water for the first stage, second stage, and third stage was 1.3:1.2:1. The cooling starting temperature was 740°C, the cooling rate was 15°C / s, and the red-hot temperature was 450°C. The surface was then treated by shot blasting, with a controlled shot blasting rate of 1100kg / min, a shot blasting speed of 70m / s, and a dust removal air volume of 60,000m. 3 / h. After surface treatment, a protective gas-water mist mixed quenching process was used at a quenching temperature of 880°C, a quenching time of 40 minutes, and a cooling rate of 20°C / s. Finally, tempering was performed at 300°C for 90 minutes to obtain an 1100 MPa corrosion-resistant steel plate.

[0069] The test results show that the yield strength of the 1100MPa corrosion-resistant steel plate is 1170MPa, the tensile strength is 1372MPa, and the impact energy at -40°C is 50J. After the obtained 1100MPa corrosion-resistant steel plate was immersed in a 3.5% NaCl solution for 168 hours, the corrosion rate was measured to be 5.1mg / cm 2 .

[0070] Example 2

[0071] Compared with Example 1, the content of silicon in the ingot was changed.

[0072] The content of silicon is 0.06%. Other process steps and parameters are the same as those in Example 1.

[0073] The test results show that the yield strength of the 1100MPa corrosion-resistant steel plate is 1187MPa, the tensile strength is 1385MPa, and the impact energy at -40°C is 42J. After the obtained 1100MPa corrosion-resistant steel plate was immersed in a 3.5% NaCl solution for 168 hours, the corrosion rate was measured to be 5.6mg / cm 2 .

[0074] Example 3

[0075] Compared with Example 1, the content of chromium in the ingot was changed.

[0076] The content of Cr element is 0.50%. Other process steps and parameters are the same as those in Example 1.

[0077] The test results show that the yield strength of the 1100MPa corrosion-resistant steel plate is 1153MPa, the tensile strength is 1354MPa, and the impact energy at -40°C is 55J. After the obtained 1100MPa corrosion-resistant steel plate was immersed in a 3.5% NaCl solution for 168 hours, the corrosion rate was measured to be 5.8mg / cm 2 .

[0078] Example 4

[0079] Compared with Example 1, the start temperature of the finish rolling was changed.

[0080] The start rolling temperature of the finishing rolling is 880° C. Other process steps and parameters are the same as those in Example 1.

[0081] The test results show that the yield strength of the 1100MPa corrosion-resistant steel plate is 1158MPa, the tensile strength is 1362MPa, and the impact energy at -40°C is 54J. After the obtained 1100MPa corrosion-resistant steel plate was immersed in a 3.5% NaCl solution for 168 hours, the corrosion rate was measured to be 5.4mg / cm 2 .

[0082] Example 5

[0083] Compared with Example 1, the shot blasting amount in the shot blasting process was changed.

[0084] The other process steps and parameters are the same as those in Example 1.

[0085] The test results show that the yield strength of the 1100MPa corrosion-resistant steel plate is 1165MPa, the tensile strength is 1366MPa, and the impact energy at -40°C is 52J. After the obtained 1100MPa corrosion-resistant steel plate was immersed in a 3.5% NaCl solution for 168 hours, the corrosion rate was measured to be 5.6mg / cm 2 .

[0086] Comparative Example 1

[0087] Compared with Example 1, the content of silicon in the ingot was changed.

[0088] The silicon content in the ingot was 0.20%. The other process steps and parameters were the same as those in Example 1, and a 1100 MPa grade steel plate was obtained.

[0089] The test results show that the yield strength of the 1100MPa grade steel plate is 1210MPa, the tensile strength is 1403MPa, and the impact energy at -40℃ is 28J. After the obtained 1100MPa grade corrosion-resistant steel plate was immersed in a 3.5% NaCl solution for 168 hours, the corrosion rate was measured to be 6.8mg / cm 2 .

[0090] Comparative Example 2

[0091] Compared with Example 1, the content of chromium in the ingot was changed.

[0092] The chromium content in the ingot is 0.20%. The other process steps and parameters are the same as those in Example 1, and a 1100 MPa grade steel plate is obtained.

[0093] The test results show that the yield strength of the 1100MPa grade steel plate is 1135MPa, the tensile strength is 1342MPa, and the impact energy at -40℃ is 54J. After the obtained 1100MPa grade corrosion-resistant steel plate was immersed in a 3.5% NaCl solution for 168 hours, the corrosion rate was measured to be 7.2mg / cm 2 .

[0094] Comparative Example 3

[0095] Compared with Example 1, the start temperature of the finish rolling was changed.

[0096] The start temperature of the finishing rolling is 930° C. The other process steps and parameters are the same as those in Example 1, and a 1100 MPa grade steel plate is obtained.

[0097] The test results show that the yield strength of the 1100MPa grade steel plate is 1140MPa, the tensile strength is 1350MPa, and the impact energy at -40℃ is 55J. After the obtained 1100MPa grade corrosion-resistant steel plate was immersed in a 3.5% NaCl solution for 168 hours, the corrosion rate was measured to be 6.5mg / cm 2 .

[0098] Comparative Example 4

[0099] Compared with Example 1, the shot blasting amount in the shot blasting process was changed.

[0100] The shot blasting rate was 600 kg / min. Other process steps and parameters were the same as those in Example 1, and a 1100 MPa grade steel plate was obtained.

[0101] The test results show that the yield strength of the 1100MPa grade steel plate is 1155MPa, the tensile strength is 1356MPa, and the impact energy at -40℃ is 52J. After the obtained 1100MPa grade corrosion-resistant steel plate was immersed in a 3.5% NaCl solution for 168 hours, the corrosion rate was measured to be 6.6mg / cm 2 .

[0102] Comparative Example 5

[0103] Compared with Example 1, the shot blasting amount in the shot blasting process was changed.

[0104] The shot blasting rate was 1200 kg / min. Other process steps and parameters were the same as those in Example 1, and a 1100 MPa grade steel plate was obtained.

[0105] The test results show that the yield strength of the 1100MPa grade steel plate is 1174MPa, the tensile strength is 1373MPa, and the impact energy at -40℃ is 46J. After the obtained 1100MPa grade corrosion-resistant steel plate was immersed in a 3.5% NaCl solution for 168 hours, the corrosion rate was measured to be 7.0mg / cm 2 .

[0106] Comparative Example 6

[0107] Compared with Example 1, the quenching method was changed.

[0108] The quenching method is water-cooling quenching. Other process steps and parameters are the same as those in Example 1, and a 1100 MPa grade steel plate is obtained.

[0109] The test results show that the yield strength of the 1100MPa grade steel plate is 1160MPa, the tensile strength is 1362MPa, and the impact energy at -40℃ is 48J. After the obtained 1100MPa grade corrosion-resistant steel plate was immersed in a 3.5% NaCl solution for 168 hours, the corrosion rate was measured to be 6.8mg / cm 2 .

[0110] in, Figure 1 This is a SEM image of the 1100 MPa-grade corrosion-resistant steel plate of the present invention. The 1100 MPa-grade corrosion-resistant steel plate of the present invention has a tempered martensite structure. As can be seen from Examples 1 to 5, by adjusting the appropriate chemical composition and content, combined with process control, the 1100 MPa-grade corrosion-resistant steel plate achieves a yield strength ≥1150 MPa, a tensile strength ≥1350 MPa, an impact energy ≥40 J at -40°C, and a low corrosion rate. This effectively improves the surface quality and performance of the 1100 MPa-grade corrosion-resistant steel plate. In Comparative Example 1, however, the corresponding silicon content is too high, causing it to react with oxygen in the steel plate, forming FeO / Fe2SiO4 pins that are pinned to the surface, making complete descaling difficult. This reduces corrosion resistance and low-temperature toughness, resulting in excessively low impact energy at -40°C. In Comparative Example 2, the corresponding chromium content is low, significantly reducing corrosion resistance. In Comparative Example 3, the start temperature of the finish rolling is too high, resulting in grain coarsening and reduced yield strength. In Comparative Examples 4 and 5, the shot blasting rate was too low, resulting in incomplete surface treatment of the steel plate and increased scale residue. Excessive shot blasting resulted in a rough surface and increased energy consumption. In Comparative Example 6, water-cooling quenching was used, resulting in uneven cooling and the absence of a protective gas. The resulting oxide layer reduced the corrosion resistance of the steel plate.

[0111] Moreover, the process method of the present invention is simple and easy to operate, which reduces production costs and energy consumption and is suitable for large-scale industrial production. The 1100MPa-grade corrosion-resistant steel plate produced has wide applicability and can effectively improve the corrosion resistance of steel plates in fields such as engineering machinery and oil and gas transportation.

[0112] In summary, the above technical solutions of the present invention are only preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention's description and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A 1100MPa corrosion-resistant steel plate, characterized in that: The chemical composition of the 1100 MPa grade corrosion-resistant steel plate, calculated by mass fraction, includes: C 0.15-0.21%, Si 0.06-0.10%, Mn 1.30-1.80%, Cr 0.50-0.80%, Mo 0.20-0.30%, B 0.002-0.005%, P≤0.015%, S≤0.005%, Nb+V+Ti 0.04-0.09%, and the balance is Fe and other unavoidable impurities; The microstructure of the 1100MPa grade corrosion-resistant steel plate is tempered martensite, the yield strength is ≥1150MPa, the tensile strength is ≥1350MPa, and the impact energy at -40°C is ≥40J.

2. The 1100 MPa corrosion-resistant steel plate according to claim 1, characterized in that: The 1100MPa corrosion-resistant steel plate has a thickness of 10 to 30mm and a width of 1800 to 4300mm.

3. A method for preparing the 1100 MPa corrosion-resistant steel plate according to claim 1 or 2, characterized in that: The following steps are involved: The ingot is heated, rough rolled, finished rolled, cooled, surface treated, quenched and tempered in sequence to obtain 1100MPa corrosion-resistant steel plate; The chemical composition of the ingot is the same as that of the 1100MPa grade corrosion-resistant steel plate; The heating temperature is 1200-1260°C and the holding time is 30-50 minutes; The cooling adopts three-stage cooling distributed along the traveling direction of the slab after finish rolling. In terms of volume ratio, the cooling water volume ratio of the first stage: the second stage: the third stage is (1.3-1.6): (1.2-1.4):

1.

4. The method for preparing the 1100 MPa corrosion-resistant steel plate according to claim 3, characterized in that: The starting rolling temperature of the rough rolling is 1100-1200°C, and the finishing rolling temperature is 980-1050°C; the thickness of the intermediate billet after the rough rolling is 4-8 times the target rolling thickness; Wherein, the rough rolling includes 5 to 8 rolling passes; the single-pass reduction ratio of at least three rolling passes is ≥15%, and the single-pass reduction ratio of at least one rolling pass is ≥20%.

5. The method for preparing the 1100 MPa corrosion-resistant steel plate according to claim 3, wherein: The start rolling temperature of the finishing rolling is 850-890°C, and the final rolling temperature is 750-800°C; The finishing rolling includes 7 to 11 rolling passes, and the reduction rate of each pass is 6 to 15%.

6. The method for preparing the 1100 MPa corrosion-resistant steel plate according to claim 3, characterized in that: The cooling starting temperature is 720-760° C., the cooling rate is 12-18° C. / s, and the red-returning temperature is 450-500° C.

7. The method for preparing the 1100 MPa corrosion-resistant steel plate according to claim 3, wherein: The surface treatment adopts high-speed shot blasting process; Among them, the shot blasting amount is 950~1150kg / min, the shot blasting speed is 65~75m / s, and the dust removal air volume is 55000~65000m 3 / h.

8. The method for preparing the 1100 MPa corrosion-resistant steel plate according to claim 3, wherein: The quenching adopts a protective gas-water mist mixed quenching process; Among them, the quenching temperature is 860-920°C, and the cooling rate is 15-30°C / s; The protective gas includes at least one of nitrogen, argon and carbon dioxide.

9. The method for preparing the 1100 MPa corrosion-resistant steel plate according to claim 3, wherein: The tempering temperature is 250-300° C., and the tempering time is 60-120 minutes.

10. Use of the 1100 MPa corrosion resistant steel plate according to claim 1 or 2, or the 1100 MPa corrosion resistant steel plate produced by the production method according to any one of claims 3 to 9, in the field of engineering machinery.

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