High-toughness, corrosion-resistant and easy-to-weld steel for anchor chain

Abstract

The invention relates to the technical field of alloy steel, and discloses high-toughness, corrosion-resistant and easy-to-weld anchor chain steel which comprises core functional components, limiting elements and the balance of Fe. The core functional components comprise C, Si, Mn, Al, Cr, Cu, Ni, Mo, V and N, and the limiting elements comprise Ti, B and Nb. By regulating and controlling a high aluminum-chromium-copper-nickel and titanium-boron-free alloy system, aluminum and nitrogen are combined to generate dispersed aluminum nitride particles, an austenite grain boundary is pinned to refine grains, meanwhile, chromium, copper and nickel cooperate to construct a compact protective layer on the steel surface, and chloride ion erosion is inhibited; the contents of titanium, boron and niobium are synchronously and strictly controlled, brittle phases or inclusions are prevented from being formed, the strength and toughness, corrosion resistance and weldability are synergistically improved, the service requirements of the anchor chain in alternating load and high-corrosion environments are met, and the problem that in the prior art, single performance optimization causes sacrifice of other performance is solved.

Description

Technical Field

[0001] This invention relates to the field of alloy steel technology, specifically to a high-strength, high-toughness, corrosion-resistant, and easy-to-weld steel for anchor chains. Background Technology

[0002] Anchor chain steel is a special type of steel used to manufacture anchor chains for marine engineering equipment (such as international shipping vessels, offshore floating platforms, and port facilities). As a key load-bearing component connecting equipment to the seabed, the anchor chain needs to be used for a long time in extreme environments with high chloride ion concentration, low temperature, and alternating loads. Therefore, there are comprehensive and stringent requirements for the strength, toughness, corrosion resistance, and weldability of anchor chain steel. Its performance directly determines the service safety and service life of the anchor chain.

[0003] In existing technologies, to meet the performance requirements of anchor chain steel, some solutions refine the room temperature microstructure by adding vanadium to improve strength and toughness, and combine it with copper, nickel, and calcium to improve resistance to alkaline corrosion. Other solutions focus on the interaction between titanium and aluminum to design a grain refinement scheme, while limiting the content of elements such as chromium, copper, and nickel to reduce weld sensitivity. Some solutions also further optimize the strength and toughness balance and microstructure stability of the steel by controlling the ratio of manganese to molybdenum, titanium to aluminum, and nitrogen.

[0004] The most critical shortcoming of existing technologies is that it is difficult to achieve synergistic results in strength, toughness, corrosion resistance and weldability within a single anchor chain steel system. Often, other properties are sacrificed in order to optimize one property. For example, adding boron to improve hardenability can lead to grain boundary embrittlement and increased sensitivity to weld cracks, while adding titanium to refine grains can increase costs and may reduce corrosion resistance. This technology cannot meet the actual needs of anchor chains for synergistic performance in extreme service environments. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a high-strength, high-toughness, corrosion-resistant, and easily weldable steel for anchor chains, thus solving the problems mentioned in the background section.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: a high-strength, high-toughness, corrosion-resistant, and easy-to-weld steel for anchor chains, comprising core functional components, limiting elements, and a balance of Fe; the core functional components include C, Si, Mn, Al, Cr, Cu, Ni, Mo, V, and N, and the limiting elements include Ti, B, and Nb.

[0007] Preferably, the mass percentages of each component are as follows: C 0.27–0.33%, Si 0.15–0.55%, Mn 1.30–1.90%, Al 0.02–0.04%, Cr 0.1–1.0%, Cu 0.01–2.0%, Ni 0.01–2.0%, Mo 0.01–0.5%, V 0.01–0.1%, N 0.01–0.013%; the upper limit of the mass percentage of the restricted elements is Ti ≤0.001%, B ≤0.0005%, Nb ≤0.001%.

[0008] A method for preparing the high-strength, high-toughness, corrosion-resistant, and easily weldable anchor chain steel as described in claim 1 or 2, comprising the following steps: S1 alloy smelting involves feeding the core functional component raw materials and Fe into an electric arc furnace in a specific ratio, controlling the amount of Ti, B, and Nb introduced into the raw materials, setting the smelting temperature and holding time for melting, and obtaining the initial molten steel. S2 steel refining: Take the initial steel obtained from S1, add Al as the main deoxidizer to the steel, adjust the amount of Al added to control the mass percentage of Al in the steel at 0.02-0.04%, remove impurities in the steel, set the refining temperature and refining time for purification treatment, and obtain refined steel. S3 continuous casting is used to take the refined molten steel obtained from S2 and send it into the continuous casting equipment. The continuous casting cooling rate is set to avoid shrinkage cavities and porosity defects inside the billet. The billet cross-sectional size is set according to the subsequent rolling requirements to complete the continuous casting and obtain the billet. S4 Homogenization treatment: Take the billet obtained from S3, put it into a heating furnace and heat it to 1100-1200℃, hold it for 2-3 hours, so that the internal structure of the billet is homogenized and the casting stress is eliminated, and a homogenized billet is obtained. S5 hot rolling: Take the homogenized billet obtained from S4, perform multiple hot rolling passes in the austenitic temperature range, set the rolling deformation amount to ensure that the steel obtains a fine rolling structure, and complete the rolling to obtain hot rolled steel. S6 post-rolling cooling: Take the hot-rolled steel obtained from S5 and cool it to room temperature using natural cooling method to obtain cooled steel. S7 finished product heat treatment: Take the cooled steel obtained from S6 and send it into a heat treatment furnace for tempering treatment. Heat it to 550-650℃, hold it for 110-130 minutes, and then air cool it to room temperature to promote the formation of dispersed precipitates and obtain steel for anchor chains.

[0009] Preferably, the smelting temperature of the electric arc furnace in S1 is set to 1550-1650℃, and the holding time is set to 60-90 minutes.

[0010] Preferably, the refining temperature in step S2 is set to 1500–1580°C, and the refining time is set to 40–60 minutes.

[0011] Preferably, in S3, the continuous casting cooling rate is set to 5-15℃ / min, the anchor chain billet size is 120mm-300mm, and the rolled diameter is 12-190mm.

[0012] Preferably, the austenite temperature range in S5 is set to 950–1100°C, and the rolling deformation is controlled at 60–80%.

[0013] Preferably, during the accelerated cooling process in S6, the temperature fluctuation range is controlled within 20–30 °C / min.

[0014] Preferably, the heating rate of the tempering treatment in S7 is set to 10-15°C / min.

[0015] An application of the high-strength, high-toughness, corrosion-resistant, and easy-to-weld anchor chain steel as described in claim 1 or 2, wherein the anchor chain steel is used to manufacture anchor chains for marine engineering equipment or anchor chains for international shipping vessels; the anchor chain is used in service environments with high chloride ion concentration, low temperature, and alternating loads, and is adapted to anchor chain welding connection processes.

[0016] This invention provides a high-strength, high-toughness, corrosion-resistant, and easily weldable steel for anchor chains. It possesses the following beneficial effects: 1. This invention regulates the alloy system of high aluminum-chromium-copper-nickel and titanium-free-boron, enabling aluminum to combine with nitrogen to form dispersed aluminum nitride particles, which pin the austenite grain boundaries to refine the grains. At the same time, chromium, copper, and nickel work together to build a dense protective layer on the steel surface, inhibiting chloride ion corrosion. Simultaneously, the content of titanium, boron, and niobium is strictly controlled to avoid the formation of brittle phases or inclusions, achieving a synergistic improvement in strength, toughness, corrosion resistance, and weldability. This invention is suitable for the service requirements of anchor chains under alternating loads and highly corrosive environments, solving the problem of other performance sacrifices caused by single performance optimization in existing technologies.

[0017] 2. This invention links the alloy smelting, continuous casting, hot rolling and tempering processes. In the smelting stage, the proportion of core functional components is precisely controlled. In the continuous casting stage, the cooling rate is adjusted to avoid shrinkage and porosity. In the rolling stage, the deformation is controlled in the austenite range to refine the microstructure. In the tempering stage, aluminum nitride and carbides are dispersed and precipitated. The design of each process link and composition forms a closed loop, which ensures the uniform microstructure of the thick section anchor chain after heat treatment. This solves the problem that a single process cannot simultaneously achieve hardenability and performance uniformity, and ensures the stability of mass production.

[0018] 3. This invention utilizes an aluminum-nitrogen grain refinement mechanism and a multi-element corrosion-resistant element linkage design to replace the grain refinement effect of titanium with dispersed aluminum nitride, thus avoiding the increased cost and processing defects associated with titanium. It also leverages the synergistic effect of chromium-copper-nickel to enhance corrosion resistance, overcoming the limitations of relying on a single corrosion-resistant element in existing technologies. Furthermore, by matching process parameters and composition ranges, it avoids the sensitivity to welding cracks caused by boron, thereby reducing production costs while improving the overall service performance and process adaptability of anchor chain steel. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating the manufacturing process of high-strength, tough, corrosion-resistant, and easily weldable anchor chain steel. Figure 2 This is a schematic diagram of the hardenability of Comparative Example 1 and Examples 1-3 of the present invention; Figure 3 This is a schematic diagram of the rolled OM microstructure of Comparative Example 1 and Examples 1-3 of the present invention; Figure 4 These are schematic diagrams of the rolled SEM microstructure of Comparative Example 1 and Examples 1-3 of the present invention; Figure 5 This is a schematic diagram of the impact energy of Comparative Example 1 and Examples 1-3 of the present invention; Figure 6 This is a schematic diagram of the typical impact fracture shape of Comparative Example 1 and Examples 1-3 of the present invention. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] This invention provides a high-strength, high-toughness, corrosion-resistant, and easily weldable anchor chain steel, comprising: C 0.27–0.33%, Si 0.15–0.55%, Mn 1.30–1.90%, Al 0.02–0.04%, Cr 0.1–1.0%, Cu 0.01–2.0%, Ni 0.01–2.0%, Mo 0.01–0.5%, V 0.01–0.1%, N 0.01–0.013%, Ti ≤0.001%, B ≤0.0005%, and Nb ≤0.001%.

[0022] Please see the appendix Figure 1 - Appendix Figure 6 A method for preparing high-strength, high-toughness, corrosion-resistant, and easily weldable anchor chain steel includes the following steps: Example 1: Steel for anchor chains based on standard composition S1 alloy smelting: The core functional components (C 0.27%, Si 0.15%, Mn 1.30%, P 0.020%, S 0.006%, Al 0.02%, Cr 0.1%, Cu 0.01%, Ni 0.01%, Mo 0.01%, V 0.01%, N 0.01%) and the balance Fe are added to an electric arc furnace in a specific ratio; the amount of Ti, B, and Nb introduced into the raw materials is strictly controlled to ensure that Ti ≤ 0.001%, B ≤ 0.0005%, and Nb ≤ 0.001%; ​​the smelting temperature is set at 1550℃ and the holding time is 60 minutes. After the raw materials are completely melted and the composition is homogeneous, the initial molten steel is obtained. S2 steel refining: Take the initial steel liquid of S1, add Al as the main deoxidizer to the steel liquid, adjust the amount of Al added to stabilize the mass percentage of Al in the steel liquid at 0.02%, and remove excess impurities in the steel liquid at the same time; set the refining temperature to 1500℃ and the refining time to 40 minutes, and obtain the refined steel liquid after purification. S3 continuous casting: Take the refined steel liquid of S2 and send it into the continuous casting equipment. Control the continuous casting cooling rate to 5℃ / min. Set the billet cross-section size to 150mm×150mm according to the subsequent rolling requirements. Complete the continuous casting to obtain the billet. S4 billet homogenization treatment: Take the S3 billet, put it into a heating furnace and heat it to 1100℃, hold it for 2.5 hours to obtain a homogenized billet; S5 hot rolling: Take the homogenized billet of S4 and perform multi-pass hot rolling in the austenitic temperature range of 950℃, control the rolling deformation to 60%, and complete the rolling to obtain hot-rolled steel. S6 Post-rolling cooling: Take S5 hot-rolled steel, use natural cooling method, ambient temperature 20-30℃, cool to room temperature to obtain cooled steel; S7 Finished Product Heat Treatment: Take the cooled S6 steel and send it into a heat treatment furnace for tempering. Set the heating rate to 10℃ / min, heat to 550℃, hold for 30 minutes, and then air cool to room temperature to promote the formation of dispersed precipitates such as AlN and carbides, and obtain high Al-Cr-Cu-Ni-OTi-OB type anchor chain steel, which is suitable for conventional marine anchor chains.

[0023] Example 2: Steel for anchor chains with medium content of functional components The difference from Example 1 is as follows: In the S1 alloy smelting, the mass percentage of the core functional components is C 0.30%, Si 0.35%, Mn 1.60%, P 0.017%, S 0.005%, Al 0.03%, Cr 0.5%, Cu 1.00%, Ni 1.00%, Mo 0.25%, V 0.05%, N 0.012%, and the limiting elements are Ti≤0.001%, B≤0.0005%, and Nb≤0.001%; ​​in the S4 billet homogenization treatment, the heating temperature is 1150℃ and the holding time is 2.5 hours; in the S5 hot rolling, the austenite temperature range is 1000℃ and the rolling deformation is 70%; the remaining steps are the same as in Example 1, resulting in anchor chain steel suitable for marine engineering equipment anchor chains, meeting the requirements of chloride ion corrosion resistance and strength-toughness balance.

[0024] Example 3: Steel for anchor chains with high functional component content The difference from Example 1 is that in the S1 alloy smelting, the mass percentage of the core functional components is C 0.33%, Si 0.55%, Mn 1.90%, P 0.016%, S 0.004%, Al 0.04%, Cr 1.0%, Cu 2.00%, Ni 2.00%, Mo 0.5%, V 0.1%, N 0.013%, with the limiting elements Ti ≤ 0.001%, B ≤ 0.0005%, and Nb ≤ 0.001%. This reaches the upper limits for C, Si, Mn, Al, and Cr, while Cu / Ni, Mo, V, and N are all within the specified ranges. In the S2 steel refining process, the refining temperature is 1580℃ and the refining time is 60 minutes to enhance the impurity removal effect. In the S3 continuous casting process, the continuous casting cooling rate is 15℃ / min and the billet cross-section size is 200mm×200mm to meet the thick cross-section requirements of heavy anchor chains. In the S7 finished product heat treatment process, the tempering temperature is 650℃ and the holding time is 2.5 hours to improve tempering stability and meet the load-bearing requirements of heavy anchor chains. The remaining steps are the same as in Example 1, resulting in anchor chain steel suitable for heavy ship anchor chains, which meets the technical design of high Cr / Cu / Ni to improve corrosion resistance and high Al to refine grains.

[0025] Comparative Example 1: Steel used for anchor chains with excessive Ti / B / Nb content The difference from Example 1 is that in the smelting of S1 alloy, the restricted elements introduced by the raw materials exceeded the limits, specifically Ti 0.014%, B 0.0023%, and Nb 0.002%, all of which exceeded the limits of Ti ≤ 0.001%, B ≤ 0.0005%, and Nb ≤ 0.001% in the example; the core functional component raw materials are C 0.31%, Si 0.28%, Mn 1.53%, P 0.020%, S 0.007%, Al, Cr, Cu, Ni, Mo, V, and N 0.0012% were not added; the remaining steps were the same as in Example 1, and the comparative steel was obtained.

[0026] Experimental process Hardenability test Referring to GB / T225-2006, the end-quenching method was adopted. Anchor chain steel billets from Examples 1-3 and Comparative Example 1 were selected and machined into standard specimens with a diameter of 25 mm and a length of 100 mm. The specimens were heated to 850℃ and held for 30 minutes before being rapidly placed in an end-quenching device. One end of the specimen was continuously cooled by water spray. After cooling, the microstructure of each cross-section of the specimen was observed using an electron microscope, the hardness values ​​at different locations were measured, and hardenability curves were plotted.

[0027] Impact toughness test Referring to GB / T229-2020, the Charpy V-notch impact test was adopted. Steels from Examples 1-3 and Comparative Example 1 were selected and processed into standard impact specimens of 10mm × 10mm × 55mm. The test temperature was set to 0℃, meeting the requirements of the marine cryogenic service environment. Each sample was tested three times, and the impact energy was recorded. The average value was taken as the final result. Simultaneously, the fracture surface of the specimens after impact was observed using a scanning electron microscope to analyze the fracture morphology.

[0028] Welding performance test Referring to GB / T4675.1-1984, a weld crack test using a beveled Y-groove was conducted, with steels from Examples 1-3 and Comparative Example 1 selected as the base materials. E5015 welding electrodes were used, with welding current controlled at 120-140A, arc voltage at 22-24V, and welding speed at 10-12cm / min. After welding, the samples were placed at room temperature for 24 hours, and then sections were taken along the weld direction for macroscopic and microscopic crack detection, and the crack rate was statistically analyzed.

[0029] Corrosion resistance test Referring to GB / T10125-2021, a neutral salt spray test was conducted. Steel samples from Examples 1-3 and Comparative Example 1 were selected and processed into standard specimens measuring 50mm × 100mm × 3mm. The test solution was a 5% sodium chloride aqueous solution, with the pH adjusted to 6.5-7.2. The test temperature was controlled at 35℃, and continuous spraying was performed for 1000 hours. After the test, the specimens were removed, the surface corrosion was observed, the corrosion rate was calculated, and the presence or absence of red rust was recorded.

[0030] Microscopic tissue observation Rolled steel samples from Examples 1-3 and Comparative Example 1 were selected and processed into metallographic specimens. After etching with 4% nitric acid alcohol solution, the grain size and microstructure were observed using a metallographic microscope (OM). Simultaneously, the morphology, size, and distribution of inclusions in the steel were observed using a scanning electron microscope (SEM), with a focus on analyzing the precipitation state of AlN particles.

[0031] Experimental conclusions Based on the test data and microscopic analysis results, the high Al-Cr-Cu-Ni-OTi-OB anchor chain steel prepared in Examples 1-3 of this invention exhibits significant advantages in hardenability and impact toughness. The excellent performance of these properties is clearly related to the alloy composition design and process control, as detailed below: A well-designed alloy composition ensures an excellent balance between strength and toughness: the average impact energy of Examples 1-3 is significantly higher than that of Comparative Example 1, with Example 2 exhibiting the best impact energy, reaching a high level. This result stems from the synergistic effect of Al and N in the alloy. The dispersed AlN particles formed by the combination of Al and N effectively pin the austenite grain boundaries, inhibit grain growth, and refine the microstructure, thereby significantly improving the impact toughness of the steel. In contrast, Comparative Example 1, lacking Al, could not form sufficient AlN particles, resulting in coarse grains and a significantly lower impact energy. Furthermore, the C content in these examples was controlled at 0.27-0.33%, ensuring both the strength of the steel and avoiding a decrease in toughness due to excessive C content, achieving a good balance between strength and toughness.

[0032] Strictly controlling the content of limiting elements improves welding performance. In Examples 1-3, with Ti ≤ 0.001%, B ≤ 0.0005%, and Nb ≤ 0.001%, the welding crack rate is almost zero. In contrast, Comparative Example 1, due to excessive Ti content (0.014%) and B content (0.0023%), shows obvious cracks after welding, with a higher crack rate. This is because Ti easily forms brittle inclusions in the weld and heat-affected zone, while B easily segregates at grain boundaries to form brittle films, both of which increase the susceptibility to welding cracks. This invention solves the problem of poor welding performance at its root by strictly controlling the content of these limiting elements, adapting to the process requirements of anchor chain welding connections.

[0033] Synergistic Enhancement of Corrosion Resistance by Multiple Corrosion-Resistant Elements: Examples 1-3 showed no obvious red rust on the surface after 1000 hours of neutral salt spray testing, and the corrosion rate was much lower than that of Comparative Example 1. This is attributed to the synergistic effect of corrosion-resistant elements such as Cr, Cu, and Ni. Cr forms a dense oxide film on the steel surface, Cu forms a stable Cu-rich protective layer, and Ni enhances the steel's resistance to chloride ion corrosion. Comparative Example 1, lacking the addition of Cr, Cu, and Ni, exhibited poor corrosion resistance, and a large amount of red rust appeared on its surface after the test.

[0034] The optimized composition range ensures good hardenability: The hardenability curves of Examples 1-3 are stable and the hardened layer depth is uniform, which can meet the processing requirements of anchor chains of different specifications. This is because the contents of elements such as Mn, Cr, and Mo are controlled within a reasonable range, which effectively improves the hardenability of the steel and ensures that the structure of the thick section anchor chain is uniform after heat treatment. However, Comparative Example 1 has poor hardenability due to the lack of synergistic effect of relevant alloying elements, and cannot meet the performance requirements of large-specification anchor chains.

[0035] Microstructure refinement enhances the overall performance of steel: Microstructure observation results show that the steels in Examples 1-3 have fine and uniform grains, with AlN particles dispersed within the grains and at grain boundaries, effectively hindering dislocation movement and grain growth. In contrast, the grains in Comparative Example 1 are significantly coarser, lacking dispersed AlN particles, and containing more and larger inclusions. This difference in microstructure directly results in the examples exhibiting superior strength, toughness, and wear resistance compared to the comparative example, fully demonstrating the effectiveness of the alloy composition design in refining the microstructure and optimizing performance.

[0036] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-strength, high-toughness, corrosion-resistant, and easily weldable steel for anchor chains, characterized in that, It includes core functional components, limiting elements, and the balance Fe; the core functional components include C, Si, Mn, Al, Cr, Cu, Ni, Mo, V, and N, and the limiting elements include Ti, B, and Nb.

2. The high-strength, high-toughness, corrosion-resistant, and easily weldable steel for anchor chains according to claim 1, characterized in that, The specific mass percentages of each component are as follows: C 0.27–0.33%, Si 0.15–0.55%, Mn 1.30–1.90%, Al 0.02–0.04%, Cr 0.1–1.0%, Cu 0.01–2.0%, Ni 0.01–2.0%, Mo 0.01–0.5%, V 0.01–0.1%, N 0.01–0.013%; the upper limits of the mass percentages of the restricted elements are Ti ≤0.001%, B ≤0.0005%, and Nb ≤0.001%.

3. A method for preparing the high-strength, high-toughness, corrosion-resistant, and easily weldable anchor chain steel as described in claim 1 or 2, characterized in that, Includes the following steps: S1 alloy smelting involves feeding the core functional component raw materials and Fe into an electric arc furnace in a specific ratio, controlling the amount of Ti, B, and Nb introduced into the raw materials, setting the smelting temperature and holding time for melting, and obtaining the initial molten steel. S2 steel refining: Take the initial steel obtained from S1, add Al as the main deoxidizer to the steel, adjust the amount of Al added to control the mass percentage of Al in the steel at 0.02-0.04%, remove impurities in the steel, set the refining temperature and refining time for purification treatment, and obtain refined steel. S3 continuous casting is used to take the refined molten steel obtained from S2 and send it into the continuous casting equipment. The continuous casting cooling rate is set to avoid shrinkage cavities and porosity defects inside the billet. The billet cross-sectional size is set according to the subsequent rolling requirements to complete the continuous casting and obtain the billet. S4 Homogenization treatment: Take the billet obtained from S3, put it into a heating furnace and heat it to 1100-1200℃, hold it for 2-3 hours, so that the internal structure of the billet is homogenized and the casting stress is eliminated, and a homogenized billet is obtained. S5 hot rolling: Take the homogenized billet obtained from S4, perform multiple hot rolling passes in the austenitic temperature range, set the rolling deformation amount to ensure that the steel obtains a fine rolling structure, and complete the rolling to obtain hot rolled steel. S6 post-rolling cooling: Take the hot-rolled steel obtained from S5 and cool it to room temperature using an accelerated cooling method to obtain cooled steel. S7 finished product heat treatment: Take the cooled steel obtained from S6 and send it into a heat treatment furnace for tempering treatment. Heat it to 550-650℃, hold it for 110-130 minutes, and then air cool it to room temperature to promote the formation of dispersed precipitates and obtain steel for anchor chains.

4. The high-strength, high-toughness, corrosion-resistant, and easily weldable steel for anchor chains according to claim 1, characterized in that, The smelting temperature of the electric arc furnace in S1 is set to 1550-1650℃, and the holding time is set to 60-90 minutes.

5. The high-strength, high-toughness, corrosion-resistant, and easily weldable steel for anchor chains according to claim 1, characterized in that, The refining temperature in S2 is set to 1500-1580℃, and the refining time is set to 40-60 minutes.

6. The high-strength, high-toughness, corrosion-resistant, and easily weldable steel for anchor chains according to claim 1, characterized in that, In S3, the continuous casting cooling rate is set to 5-15℃ / min, the anchor chain billet size is 120mm-300mm, and the rolled diameter is 12-190mm.

7. The high-strength, high-toughness, corrosion-resistant, and easily weldable steel for anchor chains according to claim 1, characterized in that, The austenite temperature range in S5 is set to 950–1100℃, and the rolling deformation is controlled at 60–80%.

8. The high-strength, high-toughness, corrosion-resistant, and easily weldable steel for anchor chains according to claim 1, characterized in that, During the accelerated cooling process in S6, the temperature fluctuation range is controlled within 20–30 °C / min.

9. The high-strength, high-toughness, corrosion-resistant, and easily weldable steel for anchor chains according to claim 1, characterized in that, The heating rate for the tempering process in S7 is set to 10-15 °C / min.

10. The application of the high-strength, high-toughness, corrosion-resistant, and easily weldable anchor chain steel as described in claim 1 or 2, characterized in that, The steel used for this anchor chain is used to manufacture anchor chains for marine engineering equipment or anchor chains for international shipping vessels; the anchor chain is used in service environments with high chloride ion concentration, low temperature and alternating loads, and is adapted to anchor chain welding connection technology.

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