High-corrosion-resistance maritime work steel plate produced through electroslag remelting and manufacturing method of high-corrosion-resistance maritime work steel plate

Abstract

The invention relates to the technical field of high-corrosion-resistance maritime work steel plates, in particular to a high-corrosion-resistance maritime work steel plate produced through electroslag remelting and a manufacturing method of the high-corrosion-resistance maritime work steel plate. The high-strength steel is composed of the following chemical components in percentage by weight: 0%-0.02% of C, 0.3%-0.5% of Si, 1.1%-1.6% of Mn, less than or equal to 0.02% of P, less than or equal to 0.01% of S, 5.0%-6.5% of Ni, 22%-25% of Cr, 2.8%-3.2% of Mo, 0.1%-0.15% of Cu, 0.1%-0.4% of Co, 0.02%-0.05% of V, 0.05%-0.15% of Sb, 0.15%-0.2% of N, less than or equal to 0.002% of O and the balance of Fe and inevitable impurities. The maximum thickness of a steel plate finished product can reach 80 mm, the impact energy of a core part at the temperature of-60 DEG C is larger than or equal to 150 J, the seawater corrosion resisting rate of the steel plate is 50% or below of the EH550 performance, the marine atmosphere corrosion resisting rate of the steel plate is 50% or below of the EH550 performance, and meanwhile the steel plate is resistant to marine organism adhesion.

Description

Technical Field

[0001] This invention relates to the field of high corrosion-resistant marine engineering steel plate technology, specifically to a high corrosion-resistant marine engineering steel plate produced by electroslag remelting and its manufacturing method. Background Technology

[0002] Since the beginning of the 21st century, the shipbuilding and marine engineering sector has developed rapidly, with increasing demand for cold-water and Arctic shipping routes, placing higher demands on related technologies and equipment. Simultaneously, as research into marine engineering steel materials for extreme environments deepens, new types of marine engineering steel materials are constantly emerging to meet increasingly stringent requirements. In recent years, the development of cold-water and Arctic shipping routes has intensified. The Arctic region possesses abundant energy resources such as oil and natural gas, thus holding enormous development potential. Along with the growth of Arctic shipping, higher demands are placed on the technology and performance of related ships and marine engineering equipment, including resistance to low temperatures, corrosion, and the Bauschinger effect. Furthermore, environmental protection issues associated with Arctic shipping routes, such as ship emissions and marine pollution, also require the support of relevant technologies and equipment. To adapt to these changes and challenges, the development of new marine engineering steel materials has become a key area. Currently, research on marine engineering steel materials focuses on advanced technologies such as microalloying, controlled rolling cooling, and heat treatment processes to improve their freeze resistance, corrosion resistance, and other properties.

[0003] Microalloying technology is also a hot research area in marine engineering steel materials. By adding appropriate trace alloying elements, the resistance of steel plates to the Bauschinger effect and their resistance to corrosion in marine environments can be significantly improved. Innovative rolling methods and optimized heat treatment processes are also important technological directions. Adopting novel rolling processes can effectively control the microstructure and phase transformation of steel, improving its low-temperature toughness and corrosion resistance.

[0004] The corrosion resistance of steel plates is crucial for the development of marine engineering equipment, significantly improving its reliability, safety, and economic efficiency. Adding appropriate trace alloying elements and employing advanced heat treatment processes can effectively enhance the corrosion resistance of steel plates. To meet the new requirements for high service safety in marine engineering steel plates, the selection of steel materials and processing techniques must comprehensively consider factors such as performance, cost, and feasibility. Although new types of marine engineering steel materials have emerged, their prices remain relatively high; therefore, reasonable choices must be made based on different needs and economic conditions in specific applications. Furthermore, in addition to trace alloying technology and heat treatment processes, ultrasonic surface modification treatment and other methods can also be used to improve corrosion resistance.

[0005] Currently, steel for marine engineering can meet most of the market demand in the marine engineering field. However, special steels with lower ductile-brittle transition temperature and excellent corrosion resistance are still the development goal of countries around the world. High-strength steel plates with high service safety are difficult to research, have strict production processes, high equipment requirements, and are difficult to develop. Summary of the Invention

[0006] To overcome the shortcomings of existing technologies, this invention provides a high corrosion-resistant marine engineering steel plate produced by electroslag remelting and its manufacturing method. Its mechanical properties and high service safety performance meet the service conditions of marine engineering equipment. The impact energy of the steel plate core at -60℃ is ≥150J. The seawater corrosion resistance rate of the steel plate is less than 50% of that of EH550, and the marine atmospheric corrosion resistance rate is less than 50% of that of EH550. At the same time, the steel plate is resistant to marine organism adhesion.

[0007] To achieve the above objectives, the present invention employs the following technical solution:

[0008] A high corrosion-resistant marine engineering steel plate produced by electroslag remelting is composed of the following chemical composition by weight percentage:

[0009] C: 0%~0.02%, Si: 0.3%~0.5%, Mn: 1.1%~1.6%, P≤0.02%, S≤0.01%, Ni: 5.0%~6.5%, Cr: 22%~25%, Mo: 2.8%~3.2%, Cu: 0.1%~0.15%, Co: 0.1%~0.4%, V: 0.02%~0.05%, Sb: 0.05%~0.15%, N: 0.15%~0.2%, O≤0.002%, with the remainder being Fe and unavoidable impurities.

[0010] The effect of selecting the above alloying elements and their contents:

[0011] 1. While carbon (C) can improve the yield and tensile strength of steel plates, it is also the biggest factor causing corrosion in steel materials. Increasing the C content significantly reduces the corrosion resistance of the steel plate, and also decreases its low-temperature toughness. Therefore, this invention precisely controls the C content to 0~0.02%.

[0012] 2. In the steelmaking process, silicon (Si) acts as a reducing agent and deoxidizer, reducing the oxygen (O) content in steel and improving the purity of the billet. Simultaneously, Si can also increase the strength of the steel plate. When the Si content is below 0.3%, the deoxidation effect is not significant; when the Si content is above 0.5%, high-alloy steel plates show a significant increase in brittle phases, resulting in reduced corrosion resistance and low-temperature toughness and plasticity. Therefore, this invention precisely controls the Si content to be between 0.3% and 0.5%.

[0013] 3. While manganese (Mn) can improve the strength of steel plates, excessive Mn levels can cause core segregation during the solidification of thick cast billets, affecting the low-temperature toughness of the core in ultra-thick steel plates. This invention employs an electroslag remelting process, which significantly reduces the impact of core segregation on the steel plate's microstructure. Adding appropriate amounts of Mn in combination with Co effectively improves the elongation properties, resistance to hydrogen-induced cracking, and fatigue corrosion resistance of thick steel plates. Therefore, this invention precisely controls the Mn content to 1.1%~1.6%.

[0014] 4. P and S elements have no benefit to the mechanical properties of steel plates, especially elongation. P should be controlled to ≤0.02% and S to ≤0.01%.

[0015] 5. The role of Ni is to improve the strength, toughness, and corrosion resistance of steel plates. The combination of Ni, Mo, and Nb in steel ensures high strength. Simultaneously, adding a large amount of Ni can lower the ductile-brittle transition temperature and improve low-temperature toughness. Furthermore, a large amount of Ni can work synergistically with Cr, Mo, and Co to enhance the corrosion resistance of the steel plate in marine environments. Therefore, this invention precisely controls the Ni content to 5.0%~6.5%.

[0016] 6. Cr can effectively improve the strength of steel plates, compensating for the insufficient strength caused by the low C content in this invention; at the same time, Cr can also form a dense oxide layer on the surface of the steel plate, effectively improving the steel plate's resistance to intergranular corrosion and pitting corrosion. Therefore, this invention precisely controls the Cr content to be 22%~25%.

[0017] 7. Mo can refine the grain size in steel, which improves the strength and fatigue corrosion resistance of the steel plate. The addition of Mo can also improve the tempering stability of the steel plate during tempering. Mo combined with Cu and Ni can also improve the steel plate's resistance to pitting corrosion, further extending its service life under corrosive marine environments. Therefore, this invention precisely controls the Mo content to be 2.8%~3.2%.

[0018] 8. Cu can increase the strength and hardness of steel, thus improving the wear resistance and fatigue corrosion resistance of steel plates. At the same time, Cu can improve the pitting corrosion resistance of steel plates, reduce the formation of fatigue crack initiation sites, and extend service life. However, excessive Cu addition will increase the tendency for hot cracking. Therefore, this invention precisely controls the Cu content to 0.1%~0.15%.

[0019] 9. Co is dissolved in the matrix of steel, which can effectively improve the hardness and strength of the steel plate, thereby significantly improving its fatigue resistance. Combined with elements such as Mn and Ni, it can improve corrosion resistance while ensuring low-temperature toughness. Furthermore, Co can prevent performance deterioration caused by carbide aggregation during heat treatment. Therefore, this invention precisely controls the Co content to 0.1%~0.4%.

[0020] 10. Vanadium (V) is an important additive element in this invention. V has a strong binding force with C and N elements in steel, forming stable CN compounds. These fine and stable precipitates are dispersed on the austenite grain boundaries, hindering austenite grain growth during heating and thus refining the grain size. The addition of V also enhances the steel plate's resistance to the Bauschinger effect. V promotes the formation of a passivation film on the steel surface, which slows down the oxidation reaction and enhances its corrosion resistance. Especially in environments containing chloride ions, vanadium significantly reduces pitting and caking corrosion. The combination of V and C improves resistance to hydrogen corrosion. Therefore, this invention precisely controls the V content to 0.02%~0.05%.

[0021] 11. Sb enhances the corrosion resistance of steel plates through multiple mechanisms. First, the addition of Sb expands the passivation range of steel, forming a protective passivation film over a wider potential range, thereby enhancing the steel's corrosion resistance. Sb promotes the formation of rust layers, which are mainly composed of α-FeOOH, γ-FeOOH, Fe3O4, and trace amounts of γ-Fe2O3, exhibiting high protective capabilities and slowing down corrosion reactions. Furthermore, Sb enrichment in the rust layer may generate Sb oxides to protect the rust layer, further enhancing corrosion resistance. Therefore, this invention precisely controls the Sb content to 0.05%~0.15%.

[0022] 12. Nitrogen (N), as a solid solution strengthening element, can work synergistically with microalloying elements during heat treatment to improve the strength and hardness of steel plates. Ni can also interact with elements such as Ni and Cr to form a dense oxide film, preventing oxygen and water penetration and thus improving the steel plate's resistance to corrosion in marine environments. However, excessive Ni content can reduce the toughness of the steel plate and increase its crack susceptibility. Therefore, this invention precisely controls the Ni content to 0.15%~0.2%.

[0023] 13. O element reduces the toughness and plasticity of steel plates. At the same time, when the O element in steel exceeds 20 ppm, it will increase the fatigue corrosion rate of steel plates during use. The O content should be controlled at ≤0.002%.

[0024] The high corrosion-resistant marine steel plate produced by the above electroslag remelting has a maximum thickness of 80mm, a yield strength ≥550MPa, a tensile strength of 720~820MPa, an elongation ≥25%, a Charpy impact energy of -60℃ in the core of the steel plate ≥150J, a seawater corrosion resistance rate of less than 50% of that of EH550, a marine atmospheric corrosion resistance rate of less than 50% of that of EH550, and is also resistant to marine organism adhesion.

[0025] The metallographic structure and CN compound morphology of the steel plate are 50%~65% ferrite + austenite + CN compound, with ferrite accounting for 50%~65% and the CN compound size being 10~60 nm.

[0026] The manufacturing method for the high corrosion-resistant marine steel plate produced by electroslag remelting adopts a process of high-cleanliness and alloying smelting + electroslag remelting + high-efficiency heating + staged high-quality rolling + normalizing. The manufacturing method specifically includes the following steps:

[0027] 1) Steel refining:

[0028] Molten steel is refined through electric furnaces, LF furnaces, and RH furnaces to further reduce the content of P, S and non-metallic inclusions.

[0029] 2) Continuous casting:

[0030] The entire casting process is protected, with the molten steel in the tundish superheated to 20~25℃. The continuous casting billet pulling speed is ≤1m / min.

[0031] 3) Electroslag remelting:

[0032] A ternary slag system is used, with a slag formation time of 90-120 minutes. Argon gas is started 20-40 minutes in advance, and argon gas is used for protection throughout the process, with an argon gas flow rate of 15-50 m³ / h. 3 In the electroslag smelting process, in addition to blowing argon gas to prevent oxidation, Al and Ca are used for deoxidation, with a total dosage of 1~3.5 kg / t. The feeding time is ≥3h, and the slow cooling time is 48~72h.

[0033] Electroslag remelting (ESR) can effectively reduce core segregation and compositional inhomogeneity caused by alloy segregation in steel plates. Simultaneously, the use of protective slag, argon protection, and deoxidizers can effectively and precisely control the chemical composition, reduce the ingress of harmful gas elements, and minimize alloy oxidation during ESR. Precise and uniform control of the alloy composition can effectively reduce the internal alloy potential difference in the steel plate, improving its corrosion resistance. Furthermore, ESR is more conducive to achieving optimal core mechanical properties in extra-thick steel plates.

[0034] 4) Rolling process:

[0035] The billet is placed into the heating furnace at a furnace temperature of 600~750℃ and held for 30~60 minutes. The temperature is then rapidly increased to the heating temperature of 1200~1300℃ for 120~150 minutes.

[0036] The purpose of placing the billet into the heating furnace for heat preservation is to maintain a consistent temperature along the thickness direction during the low-temperature stage, ensuring the uniformity of the microstructure in extra-thick slabs. Rapidly raising the temperature to 1200~1300℃ aims to ensure sufficient homogenization of the high-alloy billet while preventing abnormal growth of the as-cast microstructure.

[0037] The initial rolling temperature for the first stage is 1180~1280℃, the reduction in the first two passes is ≥60mm, and the total deformation in the first stage is 50%~60%. The initial rolling temperature for the second stage is 1000~1100℃, and the final rolling temperature is 950~1050℃.

[0038] The purpose of the first-stage rolling is to use a large reduction rolling process, taking advantage of the high temperature stage of the first two passes to increase the rolling deformation as much as possible and break the as-cast structure. The second-stage rolling process avoids abnormal growth of the intermediate billet structure while ensuring a large compression ratio deformation of the core of the intermediate billet. The low-temperature rolling at 1000~1100℃ in the ultra-low C alloy system ensures the strength and low-temperature toughness of the steel plate core.

[0039] 5) Normalizing process:

[0040] The normalizing temperature is 950~1050℃. After normalizing, air cooling or water mist cooling is used to ensure a surface cooling rate of 2~5℃ / s for the steel plate. The purpose of the normalizing process is to maintain the temperature at which CN compounds are uniformly dispersed and precipitated for a period of time, so that the size of the CN compounds is accurately within 10~60nm. The uniformly dispersed precipitates enable the steel plate to have excellent low-temperature service performance while being resistant to marine corrosion, achieving a good combination of corrosion resistance and low-temperature resistance. Controlling the cooling rate of the steel plate after normalizing also aims to control the size and distribution of the CN compounds.

[0041] Compared with the prior art, the beneficial effects of the present invention are:

[0042] 1. This invention utilizes ultra-low carbon content to improve the corrosion resistance of steel materials. Adding a large amount of Ni lowers the ductile-brittle transition temperature and improves the low-temperature toughness of the steel. Together with Cr, Mo, and Co, it enhances the corrosion resistance of the steel plate in marine environments. Adding Cu increases the strength and hardness of the steel, improving its wear resistance and fatigue corrosion resistance. Simultaneously, Cu improves the steel plate's resistance to pitting corrosion, reduces fatigue crack initiation, and extends its service life. V is a key additive element in this invention, refining the grain size and forming a passivation film on the steel surface, significantly reducing pitting and efflorescence corrosion. Adding Sb expands the passivation range of the steel, forming a protective passivation film over a wider potential range, thereby enhancing the steel's corrosion resistance.

[0043] 2. The electroslag remelting process of this invention can effectively reduce the problems of core segregation and compositional inhomogeneity. Simultaneously, the protective slag, argon protection, and deoxidizer used effectively and precisely control the chemical composition, reducing harmful gas elements and alloy oxidation. Through precise and uniform control of the alloy composition, the internal alloy potential difference of the steel plate is effectively reduced, improving the corrosion resistance of the steel plate. Furthermore, the electroslag remelting process is more conducive to achieving the core mechanical properties of extra-thick steel plates.

[0044] 3. In this invention, the billet is loaded into the heating furnace at a furnace temperature of 600~750℃ and held for 30~60 minutes to ensure that the billet maintains a uniform temperature in the thickness direction during the low-temperature stage, thus guaranteeing the uniformity of the microstructure of the extra-thick slab. Afterwards, the temperature is rapidly increased to the heating temperature of 1200~1300℃ for 120~150 minutes. The purpose of this holding process is to ensure sufficient homogenization of the high-alloy billet while preventing abnormal growth of the as-cast microstructure.

[0045] 4. The first stage of this invention employs a large reduction rolling process to break down the as-cast microstructure. As the steel plate temperature decreases, a two-phase microstructure (soft and hard) emerges. Because of the presence of Cu and Co elements in the steel, large deformation in the low-temperature rolling range easily leads to surface cracks. Therefore, it is necessary to utilize the high-temperature stages of the first two passes to maximize the rolling deformation and refine the core microstructure. This is an innovative process design based on the unique composition of this invention. The second-stage rolling process avoids abnormal growth of the intermediate billet microstructure while ensuring a large compression ratio deformation in the core of the intermediate billet. Low-temperature rolling at 1000~1100℃ in the ultra-low C alloy system ensures the strength and low-temperature toughness of the steel plate core.

[0046] 5. The normalizing temperature of this invention is 950~1050℃. After normalizing, air cooling or water mist cooling is used to ensure a surface cooling rate of 2~5℃ / s for the steel plate. The purpose of controlling the cooling rate of the steel plate after normalizing is to control the size and distribution of CN compounds, so that the size of the CN compounds is accurate to 10~60nm. This ensures that the steel plate has excellent low-temperature service performance while resisting corrosion in marine environments. The good combination of corrosion resistance and low-temperature resistance is the greatest innovative effect of this invention.

[0047] In summary, this invention employs a composition design that combines ultra-low C with high levels of Mn, Ni, Mo, Cu, Co, and microalloyed V and Sb elements. Combined with electroslag remelting, staged rolling, and normalizing processes, it has developed an ultra-high-strength steel plate with a maximum thickness of 80 mm. The steel plate exhibits a yield strength ≥ 550 MPa, tensile strength 720~820 MPa, elongation ≥ 25%, Charpy impact energy at -60℃ in the core ≥ 150 J, and seawater corrosion resistance and marine atmospheric corrosion resistance rates are both below 50% of those of EH550. Furthermore, the steel plate is resistant to marine organism adhesion. Attached Figure Description

[0048] Figure 1 This is a metallographic diagram of Embodiment 1 of the present invention.

[0049] Figure 2 This is a morphology diagram of the CN compound from Embodiment 1 of the present invention. Detailed Implementation

[0050] This invention discloses a high corrosion-resistant marine engineering steel plate produced by electroslag remelting and its manufacturing method. Those skilled in the art can refer to the content of this document and appropriately modify the process parameters to achieve the same result. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The methods and applications of this invention have been described through preferred embodiments, and those skilled in the art can obviously make modifications or appropriate alterations and combinations to the methods and applications described herein without departing from the content, spirit, and scope of this invention to realize and apply the technology of this invention.

[0051] To address the compositional performance requirements of low-temperature toughness marine engineering steel plates resistant to marine corrosion in extremely cold marine environments, this invention utilizes a compositional design combining C, Mn, Ni, Mo, Cu, Co, and microalloyed V and Sb elements, along with key production technologies for such steel plates. To achieve the objectives of this invention, extensive and systematic experimental research was conducted in several aspects, including alloy element screening and proportioning, steel cleanliness control, and optimization and parameter selection of efficient rolling processes. Ultimately, the alloy element proportions and production processes that meet the objectives of this invention were determined. The chemical composition of the steel in the embodiments of this invention is shown in Table 1, the production method in the embodiments of this invention is shown in Table 2, the tensile and impact properties in the embodiments of this invention are shown in Table 3, and the marine corrosion resistance properties in the embodiments of this invention are shown in Table 4.

[0052] Table 1. Chemical composition (wt%) of steel in the embodiments of the present invention

[0053]

[0054] Table 2 Production Method of Embodiments of the Invention

[0055]

[0056] Table 3 Tensile and impact properties of embodiments of the present invention

[0057]

[0058] Table 4. Corrosion resistance of the embodiments of the present invention in marine environments

[0059]

[0060] Note: The full immersion test reference standard JBT 7901, and the salt spray test reference standard GBT 10125. The comparison steel composition is 0.12C~0.3Si~1.20Mn~0.5Ni~0.2Cr~0.04Nb~0.04V~0.01Ti.

[0061] like Figure 1 , Figure 2 As shown, the metallographic structure and CN compound morphology of Example 1 are ferrite + austenite + CN compound, with ferrite accounting for 50%~65% and the CN compound size being 10~60nm, exhibiting good mechanical properties.

[0062] This invention employs a composition design that combines ultra-low C with high levels of Mn, Ni, Mo, Cu, Co, and microalloyed V and Sb elements. Combined with electroslag remelting, staged rolling, and normalizing processes, it has developed an ultra-high-strength steel plate with a maximum thickness of 80mm. Its mechanical properties and high service safety performance meet the requirements for marine engineering equipment. The steel plate has a yield strength ≥550MPa, tensile strength 720~820MPa, elongation ≥25%, and a Charpy impact energy of ≥150J at -60℃ in the core. Its seawater corrosion resistance rate is less than 50% of that of EH550, its marine atmospheric corrosion resistance rate is less than 50% of that of EH550, and it is also resistant to marine organism adhesion.

[0063] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A high corrosion-resistant marine steel plate produced by electroslag remelting, characterized in that, Composed of the following chemical components in weight percentage composition: C: 0%~0.02%, Si: 0.3%~0.5%, Mn: 1.1%~1.6%, P≤0.02%, S≤0.01%, Ni: 5.0%~6.5%, Cr: 22%~25%, Mo: 2.8%~3.2%, Cu: 0.1%~0.15%, Co: 0.1%~0.4%, V: 0.02%~0.05%, Sb: 0.05%~0.15%, N: 0.15%~0.2%, O≤0.002%, with the remainder being Fe and unavoidable impurities; The maximum thickness of the finished steel plate is 80mm, with a yield strength ≥550MPa, tensile strength 720~820MPa, elongation ≥25%, and Charpy impact energy of the steel plate core at -60℃ ≥150J. The metallographic structure and CN compound morphology of the steel plate are ferrite + austenite + CN compound, with ferrite accounting for 50%~65% and CN compound size ranging from 10 to 60 nm.

2. A method for manufacturing high corrosion-resistant marine steel plates produced by electroslag remelting as described in claim 1, characterized in that, The manufacturing method specifically includes the following steps: 1) Steel refining; 2) Continuous casting: The entire casting process is protected, the molten steel in the tundish is superheated to 20~25℃, and the continuous casting billet pulling speed is ≤1m / min; 3) Electroslag remelting: A ternary slag system is used, with a slag formation time of 90-120 minutes. Argon gas is started 20-40 minutes in advance, and argon gas is used for protection throughout the process, with an argon gas flow rate of 15-50 m³ / h. 3 / h; Deoxidation was performed using Al and Ca. 4) Rolling: The initial rolling temperature is 1180~1280℃; The initial rolling temperature for the second stage is 1000~1100℃, and the final rolling temperature is 950~1050℃. 5) Positive heat: The normalizing temperature is 950~1050℃, and the cooling rate is 2~5℃ / s.

3. The method for manufacturing high corrosion-resistant marine steel plates produced by electroslag remelting according to claim 2, characterized in that, In step 1), refining is carried out using an electric furnace, an LF furnace, or an RH furnace.

4. The method for manufacturing high corrosion-resistant marine steel plates produced by electroslag remelting according to claim 2, characterized in that, 3) The total amount of Al and Ca used is 1~3.5 kg / t.

5. The method for manufacturing high corrosion-resistant marine steel plates produced by electroslag remelting according to claim 2, characterized in that, 3) The compensation time is ≥3h, and the slow cooling time is 48~72h.

6. The method for manufacturing high corrosion-resistant marine steel plates produced by electroslag remelting according to claim 2, characterized in that, 4) The billet is loaded into the heating furnace at a furnace temperature of 600~750℃, held for 30~60 minutes, heated at 1200~1300℃ for 120~150 minutes.

7. The method for manufacturing high corrosion-resistant marine steel plates produced by electroslag remelting according to claim 2, characterized in that, 4) In the first stage, the reduction of the first two passes is ≥60mm, and the total deformation of the first stage is 50%~60%.

8. The method for manufacturing high corrosion-resistant marine steel plates produced by electroslag remelting according to claim 2, characterized in that, 5) After normalizing, air cooling or water mist cooling is used to ensure the cooling rate of the steel plate surface.

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