Production method of large-thickness wind power steel plate with excellent welding performance

Abstract

The invention discloses a production method of a large-thickness wind power steel plate with excellent welding performance. The large-thickness wind power steel plate comprises the following chemical components in percentage by mass: 0.07-0.15% of C, 0.15-0.50% of S i, 1.00-1.80% of Mn, less than or equal to 0.015% of P, less than or equal to 0.005% of S, 0.025-0.045% of Nb, 0.015-0.045% of T i, 0.020-0.050% of Al and the balance of Fe and other inevitable impurities. The production method comprises the procedures of steelmaking, continuous casting and rolling. The steel plate is good in comprehensive performance, the maximum production thickness reaches 80 mm, the yield strength is larger than or equal to 460 MPa, the tensile strength is 600-800 MPa, the longitudinal impact energy at-40 DEG C is larger than or equal to 100 J, the welding energy can reach larger than or equal to 100 KJ / cm, the requirements of users for the large thickness and the excellent welding performance of the steel plate for wind power are met, and the application prospect is wide.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgy, and in particular relates to a method for producing a thick steel plate for wind power with excellent welding performance. Background Art

[0002] Wind energy is a clean, safe, low-carbon and environmentally friendly renewable energy source. The development of wind energy is of great significance to the development of clean energy in my country. At present, the domestic wind power industry technology is relatively mature. Wind power towers are gradually built in coastal areas, mountains, deserts and other places with harsh environments. Therefore, thick steel plates are required. Wind power towers are connected by segmented welding. Since the use environment of wind power towers determines that all welding points cannot have defects, the steel plates must have excellent welding performance. In order to meet the excellent welding performance and other process performance of steel for wind power towers, a thick steel for wind power towers with uniform internal structure, excellent welding performance, good strength and toughness matching, and stable performance is obtained through the control of steelmaking, continuous casting and rolling.

[0003] Patent application No. 201610301108.3 discloses a Ni-free wind power steel with excellent low-temperature toughness and a production method, providing a wind power steel with excellent low-temperature toughness and a production method that does not contain Ni and has a yield strength ≥460MPa, a tensile strength of 550-720MPa, an elongation A ≥26%, an impact energy of -60℃ ≥200J, does not contain precious metal elements, and does not require heat treatment. The patent does not clearly state the thickness specifications of the produced wind power steel, nor does it specify the welding performance.

[0004] Patent application number 202211047950.0 discloses a large unit weight and thick specification TMCP wind power steel and its manufacturing method. The production thickness specification given as an example is 50-100mm, and the tensile strength is about 550MPa, but the welding performance is not clearly stated.

[0005] Patent application number 201810236449.6 discloses a wind power steel and its preparation method, which is mainly used for offshore wind power tower engineering structure steel, wherein alloy V: 0.10-0.15%, Cr: 0.80-1.35%, Mo: 0.10-0.20%, Ce: 0.08-0.15% are added, and the corresponding hot rolling + normalizing treatment is adopted to obtain a steel plate with a yield strength of ≥420MPa and a tensile strength of 50-680MPa, so as to solve the problem that the offshore wind power engineering structure steel has a high alloy content and high production cost, and the thickness specifications and welding performance of the production are not clearly stated. Summary of the invention

[0006] The purpose of the present invention is to provide a method for producing a thick steel plate for wind power with excellent welding performance. The steel plate has a thickness specification of 50-80 mm, does not require heat treatment, has low production cost, excellent welding performance, and can be promoted and used on a large scale.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] The present invention discloses a method for producing a thick steel plate for wind power with excellent welding performance. The chemical composition and mass percentage of the steel plate are as follows: C: 0.07-0.15%, Si: 0.15-0.50%, Mn: 1.00-1.80%, P≤0.015%, S≤0.005%, Nb: 0.025-0.045%, Ti: 0.015-0.045%, Al: 0.020-0.050%, and the rest is Fe and other inevitable impurities; the production method comprises a steelmaking process, a continuous casting process, and a rolling process; the rolling process adopts a type II controlled rolling process; wherein:

[0009] The steelmaking process: the molten steel smelted in the converter is sent to the LF refining furnace for refining. During the LF refining process, argon is blown throughout the whole process, the total refining time is ≥60min, and the white slag retention time is ≥30min;

[0010] After the LF furnace is finished refining, the molten steel is sent to the RH furnace for vacuum degassing treatment, the vacuum degree is ≤66.7Pa, the vacuum holding time is ≥20min, and the vacuum is soft-blown for 10-15min after the vacuum is broken, so that the inclusions can fully float up;

[0011] The continuous casting process: a thick slab continuous casting machine is used for casting, the liquid level of the crystallizer is automatically controlled, and the superheat is controlled between 15-25°C during the casting process;

[0012] The rolling process: the continuous casting billet is heated in a continuous furnace, the maximum heating temperature is 1260°C, the soaking section temperature is 1220-1240°C, and the total heating time is ≥10min / cm;

[0013] The type II controlled rolling process is adopted: the first stage rolling temperature is 1050-1150℃, the steel thickness is h+50mm, and h is the thickness of the finished steel plate; the second stage rolling temperature is 850-950℃, and the final rolling temperature is 800-850℃;

[0014] The high cooling rate and high re-redening process is adopted, the steel plate is cooled quickly after rolling, and the re-redening temperature is controlled between 500-650℃.

[0015] Furthermore, the thickness of the steel plate is 50 to 80 mm.

[0016] Furthermore, the steel plate structure is ferrite and pearlite.

[0017] Furthermore, the mechanical properties of the steel plate meet the following requirements: yield strength ≥460MPa, tensile strength 600-800MPa, longitudinal -40°C impact energy ≥100J, and welding energy can reach ≥100KJ / cm.

[0018] Furthermore, the chemical composition and mass percentage of the steel plate are: C: 0.11%, Si: 0.43%, Mn: 1.65%, P: 0.015%, S: 0.003%, Nb: 0.045%, Ti: 0.022%, Al: 0.041%, and the rest are Fe and other inevitable impurities.

[0019] Furthermore, the chemical composition and mass percentage of the steel plate are: C: 0.10%, Si: 0.15%, Mn: 1.00%, P: 0.011%, S: 0.005%, Nb: 0.041%, Ti: 0.032%, Al: 0.020%, and the rest are Fe and other inevitable impurities.

[0020] Furthermore, the chemical composition and mass percentage of the steel plate are: C: 0.15%, Si: 0.22%, Mn: 1.34%, P: 0.013%, S: 0.004%, Nb: 0.028%, Ti: 0.045%, Al: 0.045%, and the rest are Fe and other inevitable impurities.

[0021] Furthermore, the chemical composition and mass percentage of the steel plate are: C: 0.09%, Si: 0.28%, Mn: 1.75%, P: 0.014%, S: 0.003%, Nb: 0.036%, Ti: 0.037%, Al: 0.032%, and the rest are Fe and other inevitable impurities.

[0022] Furthermore, the chemical composition and mass percentage of the steel plate are: C: 0.07%, Si: 0.35%, Mn: 1.80%, P: 0.012%, S: 0.002%, Nb: 0.025%, Ti: 0.028%, Al: 0.050%, and the rest are Fe and other inevitable impurities.

[0023] Furthermore, the chemical composition and mass percentage of the steel plate are: C: 0.12%, Si: 0.50%, Mn: 1.52%, P: 0.010%, S: 0.003%, Nb: 0.030%, Ti: 0.015%, Al: 0.028%, and the rest are Fe and other inevitable impurities.

[0024] Compared with the prior art, the beneficial technical effects of the present invention are:

[0025] The present invention adopts reasonable chemical composition design, white slag refining control in the steelmaking process, vacuum time control and reasonable soft blowing process in the RH refining process, large section and strong cooling technology at the end of solidification in the continuous casting process, and casts a continuous casting billet with large section and high internal quality. During rolling, a type II controlled rolling process is adopted, and a fast cooling and high red return process is added to obtain a continuous casting billet with a material specification of 50-80mm. The delivery state of the present invention is TMCP. The large-thickness wind power steel plate with excellent welding performance obtained by adopting reasonable chemical composition design, steelmaking, continuous casting, rolling, and strong cooling after rolling has good internal structure uniformity, good strength and toughness, and excellent welding performance, which can meet the requirements of wind power tower steel in harsh environments.

[0026] The beneficial effects of the above technical scheme are: 1. The chemical composition design of the steel plate for wind power tower with excellent welding performance of the present invention is reasonable, the internal structure of the steel plate is uniform, the performance is stable, and the welding performance is excellent. 2. The present invention adopts LF, RH and soft blowing processes to reduce the endogenous non-metallic inclusions generated by molten steel. 3. The present invention uses continuous casting billet to improve the metal yield rate and greatly reduce the production cost. 4. The present invention uses a reasonable controlled rolling process to make the steel plate have good comprehensive performance, no heat treatment is required, the production cost is low, the market competitiveness is strong, and the user's requirements for thick steel for wind power are met, and the application prospects are broad. 5. The internal structure of the steel plate produced by the present invention is uniform and dense, and the structure is ferrite and pearlite. 6. The strength and toughness of the steel plate produced by the present invention are well matched, the yield strength is ≥460MPa, the tensile strength is 600-800MPa, and the longitudinal impact energy at -40℃ is ≥100J. 7. The thickness specification of the thick steel plate of the present invention is 50-80mm, the thickness range is large, and the application range is wide. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be further described below in conjunction with the accompanying drawings.

[0028] Figure 1 This is the metallographic structure of Example 1 of the present invention. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below with reference to specific embodiments.

[0030] Example 1

[0031] The thick wind power steel plate with excellent welding performance in this embodiment is 75 mm thick, and its chemical composition and mass percentage are: C: 0.11%, Si: 0.43%, Mn: 1.65%, P: 0.015%, S: 0.003%, Nb: 0.045%, Ti: 0.022%, Al: 0.041%, and the rest is Fe and other inevitable impurities.

[0032] The production method of the thick steel plate for wind power with excellent welding performance in this embodiment includes steelmaking, continuous casting, and rolling processes, and the specific process steps are as follows:

[0033] (1) Steelmaking process: The molten steel smelted in the primary refining furnace is sent to the LF refining furnace for refining. During the LF refining process, argon blowing is good throughout the process. The total refining time is 76 minutes and the white slag holding time is 31 minutes. After refining, the molten steel is sent to the RH refining furnace for vacuum degassing treatment. The vacuum degree is 35Pa and the vacuum holding time is 22 minutes. After the vacuum is broken, soft blowing is performed for 15 minutes to allow inclusions to fully float up.

[0034] (2) Continuous casting process: A thick slab continuous casting machine is used for casting. The liquid level of the crystallizer is automatically controlled. The superheat during the casting process is 25°C. Strong cooling technology is used at the end of the solidification to cast a large-section continuous casting billet with high internal quality.

[0035] (3) Rolling process: the highest heating temperature of the continuous casting billet is 1260°C, the soaking section temperature is 1230°C, and the total heating coefficient is 10 min / cm;

[0036] The controlled rolling and controlled cold rolling process is adopted, the first stage rolling temperature is 1100℃, the high pressure rolling is adopted, the steel thickness is 145mm, the second stage rolling temperature is 900℃, and the final rolling temperature is 830℃;

[0037] (4) A high cooling rate and high re-red process is adopted. The steel plate is cooled quickly after rolling, and then the re-red temperature is raised to 630°C.

[0038] After cooling, the steel plate structure is ferrite and pearlite, the yield strength of the steel plate is 482MPa, the tensile strength is 653MPa, and the longitudinal -40°C impact energy is 135J. The produced thick wind power steel plate has excellent welding performance, high strength, good impact toughness, uniform structure and stable performance.

[0039] Example 2

[0040] The thick wind power steel plate with excellent welding performance in this embodiment is 50 mm thick, and its chemical composition and mass percentage are: C: 0.10%, Si: 0.15%, Mn: 1.00%, P: 0.011%, S: 0.005%, Nb: 0.041%, Ti: 0.032%, Al: 0.020%, and the rest is Fe and other inevitable impurities.

[0041] The production method of the thick steel plate for wind power with excellent welding performance in this embodiment includes steelmaking, continuous casting, and rolling processes, and the specific process steps are as follows:

[0042] (1) Steelmaking process: The molten steel smelted in the primary refining furnace is sent to the LF refining furnace for refining. During the LF refining process, argon blowing is good throughout the process. The total refining time is 60 minutes, and the white slag holding time is 36 minutes. After refining, the molten steel is sent to the RH refining furnace for vacuum degassing treatment. The vacuum degree is 66.7Pa, the vacuum holding time is 20 minutes, and the vacuum is soft-blown for 14 minutes after the vacuum is broken to allow inclusions to fully float up.

[0043] (2) Continuous casting process: A thick slab continuous casting machine is used for casting. The liquid level of the crystallizer is automatically controlled. The superheat during the casting process is 17°C. Strong cooling technology is used at the end of the solidification to cast a large-section continuous casting billet with high internal quality.

[0044] (3) Rolling process: the highest heating temperature of the continuous casting billet is 1260°C, the soaking zone temperature is 1235°C, and the total heating coefficient is 12 min / cm;

[0045] The steel is rolled using type II controlled rolling technology, with the first stage rolling temperature at 1050°C, high reduction rolling, steel thickness at 120mm, the second stage rolling temperature at 940°C, and the final rolling temperature at 810°C.

[0046] (4) A high cooling rate and high re-red process is adopted. The steel plate is cooled quickly after rolling, and then the re-red temperature is waited to rise. The re-red temperature is controlled at 650°C.

[0047] After cooling, the steel plate structure is ferrite and pearlite, the yield strength of the steel plate is 460MPa, the tensile strength is 600MPa, and the longitudinal -40°C impact energy is 182J. The produced thick wind power steel plate has excellent welding performance, high strength, good impact toughness, uniform structure and stable performance.

[0048] Example 3

[0049] The thick wind power steel plate with excellent welding performance in this embodiment is 65 mm thick, and its chemical composition and mass percentage are: C: 0.15%, Si: 0.22%, Mn: 1.34%, P: 0.013%, S: 0.004%, Nb: 0.028%, Ti: 0.045%, Al: 0.045%, and the rest is Fe and other inevitable impurities.

[0050] The production method of the thick steel plate for wind power with excellent welding performance in this embodiment includes steelmaking, continuous casting, and rolling processes, and the specific process steps are as follows:

[0051] (1) Steelmaking process: The molten steel smelted in the primary refining furnace is sent to the LF refining furnace for refining. During the LF refining process, argon blowing is good throughout the process. The total refining time is 71 minutes, and the white slag holding time is 34 minutes. After refining, the molten steel is sent to the RH refining furnace for vacuum degassing treatment. The vacuum degree is 45Pa, and the vacuum holding time is 22 minutes. After the vacuum is broken, soft blowing is performed for 12 minutes to allow inclusions to fully float up.

[0052] (2) Continuous casting process: A thick slab continuous casting machine is used for casting. The liquid level of the crystallizer is automatically controlled. The superheat during the casting process is 15°C. Strong cooling technology is used at the end of the solidification to cast a large-section continuous casting billet with high internal quality.

[0053] (3) Rolling process: the highest heating temperature of the continuous casting billet is 1260°C, the soaking section temperature is 1240°C, and the total heating coefficient is 12 min / cm;

[0054] The steel is rolled using type II controlled rolling technology, with the first stage rolling temperature at 1067°C, high reduction rolling, steel thickness at 135mm, the second stage rolling temperature at 950°C, and the final rolling temperature at 850°C.

[0055] (4) A high cooling rate and high re-redness process is adopted. The steel plate is cooled quickly after rolling, and then the re-redness temperature is waited to rise. The re-redness temperature is controlled at 500°C.

[0056] After cooling, the steel plate has a microstructure of ferrite and pearlite, a yield strength of 541 MPa, a tensile strength of 800 MPa, and a longitudinal impact energy of 175 J at -40°C. The produced thick wind power steel plate has excellent welding performance, high strength, good impact toughness, uniform microstructure, and stable performance.

[0057] Example 4

[0058] The thick steel plate for wind power with excellent welding performance in this embodiment is 55 mm thick, and its chemical composition and mass percentage are: C: 0.09%, Si: 0.28%, Mn: 1.75%, P: 0.014%, S: 0.003%, Nb: 0.036%, Ti: 0.037%, Al: 0.032%, and the rest is Fe and other inevitable impurities.

[0059] The production method of the thick steel plate for wind power with excellent welding performance in this embodiment includes steelmaking, continuous casting, and rolling processes, and the specific process steps are as follows:

[0060] (1) Steelmaking process: The molten steel smelted in the primary refining furnace is sent to the LF refining furnace for refining. During the LF refining process, argon blowing is good throughout the process. The total refining time is 75 minutes, and the white slag holding time is 30 minutes. After refining, the molten steel is sent to the RH refining furnace for vacuum degassing treatment. The vacuum degree is 50Pa, the vacuum holding time is 19 minutes, and the vacuum is soft-blown for 11 minutes after the vacuum is broken to allow inclusions to fully float up.

[0061] (2) Continuous casting process: A thick slab continuous casting machine is used for casting. The liquid level of the crystallizer is automatically controlled. The superheat during the casting process is 19°C. Strong cooling technology is used at the end of the solidification to cast a large-section continuous casting billet with high internal quality.

[0062] (3) Rolling process: the highest heating temperature of the continuous casting billet is 1260°C, the soaking zone temperature is 1238°C, and the total heating coefficient is 11min / cm;

[0063] The steel is rolled using type II controlled rolling technology, with the first stage rolling temperature at 1075°C, high reduction rolling, steel thickness at 125mm, the second stage rolling temperature at 930°C, and the final rolling temperature at 840°C.

[0064] (4) A high cooling rate and high re-redening process is adopted. The steel plate is cooled quickly after rolling, and then the re-redening temperature is waited to rise. The re-redening temperature is controlled at 550°C.

[0065] After cooling, the steel plate has a microstructure of ferrite and pearlite, a yield strength of 472 MPa, a tensile strength of 684 MPa, and a longitudinal impact energy of 157 J at -40°C. The thick wind power steel plate produced has excellent welding performance, high strength, good impact toughness, uniform microstructure, and stable performance.

[0066] Example 5

[0067] The thick wind power steel plate with excellent welding performance in this embodiment is 70 mm thick, and its chemical composition and mass percentage are: C: 0.07%, Si: 0.35%, Mn: 1.80%, P: 0.012%, S: 0.002%, Nb: 0.025%, Ti: 0.028%, Al: 0.050%, and the rest is Fe and other inevitable impurities.

[0068] The production method of the thick steel plate for wind power with excellent welding performance in this embodiment includes steelmaking, continuous casting, and rolling processes, and the specific process steps are as follows:

[0069] (1) Steelmaking process: The molten steel smelted in the primary refining furnace is sent to the LF refining furnace for refining. During the LF refining process, argon blowing is good throughout the process. The total refining time is 68 minutes, and the white slag holding time is 40 minutes. After refining, the molten steel is sent to the RH refining furnace for vacuum degassing treatment. The vacuum degree is 40Pa, and the vacuum holding time is 20 minutes. After the vacuum is broken, soft blowing is performed for 10 minutes to allow inclusions to fully float up.

[0070] (2) Continuous casting process: A thick slab continuous casting machine is used for casting. The liquid level of the crystallizer is automatically controlled. The superheat during the casting process is 18°C. Strong cooling technology is used at the end of the solidification to cast a large-section continuous casting billet with high internal quality.

[0071] (3) Rolling process: the highest heating temperature of the continuous casting billet is 1260°C, the temperature of the soaking section is 1226°C, and the total heating coefficient is 13 min / cm;

[0072] The type II controlled rolling process is adopted, the first stage rolling temperature is 1062℃, the high pressure rolling is adopted, the steel thickness is 140mm, the second stage rolling temperature is 860℃, and the final rolling temperature is 820℃;

[0073] (4) A high cooling rate and high re-red process is adopted. The steel plate is cooled quickly after rolling, and then the re-red temperature is waited to rise. The re-red temperature is controlled at 580°C.

[0074] After cooling, the steel plate has a microstructure of ferrite and pearlite, a yield strength of 495 MPa, a tensile strength of 749 MPa, and a longitudinal impact energy of 168 J at -40°C. The thick wind power steel plate produced has excellent welding performance, high strength, good impact toughness, uniform microstructure, and stable performance.

[0075] Example 6

[0076] The thick steel plate for wind power with excellent welding performance in this embodiment is 80 mm thick, and its chemical composition and mass percentage are: C: 0.12%, Si: 0.50%, Mn: 1.52%, P: 0.010%, S: 0.003%, Nb: 0.030%, Ti: 0.015%, Al: 0.028%, and the rest is Fe and other inevitable impurities.

[0077] The production method of the thick steel plate for wind power with excellent welding performance in this embodiment includes steelmaking, continuous casting, and rolling processes, and the specific process steps are as follows:

[0078] (1) Steelmaking process: The molten steel smelted in the primary refining furnace is sent to the LF refining furnace for refining. During the LF refining process, argon blowing is good throughout the process. The total refining time is 65 minutes, and the white slag holding time is 35 minutes. After refining, the molten steel is sent to the RH refining furnace for vacuum degassing treatment. The vacuum degree is 48Pa, and the vacuum holding time is 21 minutes. After the vacuum is broken, soft blowing is performed for 15 minutes to allow inclusions to fully float up.

[0079] (2) Continuous casting process: A thick slab continuous casting machine is used for casting. The liquid level of the crystallizer is automatically controlled. The superheat during the casting process is 20°C. Strong cooling technology is used at the end of the solidification to cast a large-section continuous casting billet with high internal quality.

[0080] (3) Rolling process: the highest heating temperature of the continuous casting billet is 1260°C, the soaking section temperature is 1220°C, and the total heating coefficient is 11min / cm;

[0081] Adopting type II controlled rolling process, the first stage rolling temperature is 1150℃, large reduction rolling is adopted, the steel thickness is 150mm, the second stage rolling temperature is 880℃, and the final rolling temperature is 800℃;

[0082] (4) A high cooling rate and high re-red process is adopted. The steel plate is cooled quickly after rolling, and then the re-red temperature is waited to rise. The re-red temperature is controlled at 600°C.

[0083] After cooling, the steel plate has a microstructure of ferrite and pearlite, a yield strength of 523 MPa, a tensile strength of 756 MPa, and a longitudinal impact energy of 191 J at -40°C. The thick wind power steel plate produced has excellent welding performance, high strength, good impact toughness, uniform microstructure, and stable performance.

[0084] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for producing a thick steel plate for wind power with excellent welding performance, characterized in that: The chemical composition and mass percentage of the steel plate are: C: 0.07-0.15%, Si: 0.15-0.50%, Mn: 1.00-1.80%, P≤0.015%, S≤0.005%, Nb: 0.025-0.045%, Ti: 0.015-0.045%, Al: 0.020-0.050%, and the rest are Fe and other inevitable impurities; the production method includes steelmaking process, continuous casting process, and rolling process; the rolling process adopts type II controlled rolling process; wherein: The steelmaking process: the molten steel smelted in the converter is sent to the LF refining furnace for refining. During the LF refining process, argon is blown throughout the whole process, the total refining time is ≥60min, and the white slag retention time is ≥30min; After the LF furnace is finished refining, the molten steel is sent to the RH furnace for vacuum degassing treatment, the vacuum degree is ≤66.7Pa, the vacuum holding time is ≥20min, and the vacuum is soft-blown for 10-15min after the vacuum is broken, so that the inclusions can fully float up; The continuous casting process: a thick slab continuous casting machine is used for casting, the liquid level of the crystallizer is automatically controlled, and the superheat is controlled between 15-25°C during the casting process; The rolling process: the continuous casting billet is heated in a continuous furnace, the maximum heating temperature is 1260°C, the soaking section temperature is 1220-1240°C, and the total heating time is ≥10min / cm; The type II controlled rolling process is adopted: the first stage rolling temperature is 1050-1150℃, the steel thickness is h+50mm, and h is the thickness of the finished steel plate; the second stage rolling temperature is 850-950℃, and the final rolling temperature is 800-850℃; The high cooling rate and high re-redening process is adopted, the steel plate is cooled quickly after rolling, and the re-redening temperature is controlled between 500-650℃.

2. The method for producing a thick steel plate for wind power generation with excellent welding performance according to claim 1, characterized in that: The thickness of the steel plate is 50 to 80 mm.

3. The method for producing a thick steel plate for wind power generation with excellent welding performance according to claim 1, characterized in that: The steel plate structure is ferrite and pearlite.

4. The method for producing a thick steel plate for wind power generation with excellent welding performance according to claim 1, characterized in that: The mechanical properties of the steel plate meet the following requirements: yield strength ≥460MPa, tensile strength 600-800MPa, longitudinal -40°C impact energy ≥100J, and welding energy can reach ≥100KJ / cm.

5. The method for producing a thick steel plate for wind power with excellent welding performance according to claim 1, characterized in that: The chemical composition and mass percentage of the steel plate are: C: 0.11%, Si: 0.43%, Mn: 1.65%, P: 0.015%, S: 0.003%, Nb: 0.045%, Ti: 0.022%, Al: 0.041%, and the rest are Fe and other inevitable impurities.

6. The method for producing a thick steel plate for wind power generation with excellent welding performance according to claim 1, characterized in that: The chemical composition and mass percentage of the steel plate are: C: 0.10%, Si: 0.15%, Mn: 1.00%, P: 0.011%, S: 0.005%, Nb: 0.041%, Ti: 0.032%, Al: 0.020%, and the rest are Fe and other inevitable impurities.

7. The method for producing a thick steel plate for wind power generation with excellent welding performance according to claim 1, characterized in that: The chemical composition and mass percentage of the steel plate are: C: 0.15%, Si: 0.22%, Mn: 1.34%, P: 0.013%, S: 0.004%, Nb: 0.028%, Ti: 0.045%, Al: 0.045%, and the rest are Fe and other inevitable impurities.

8. The method for producing a thick steel plate for wind power generation with excellent welding performance according to claim 1, characterized in that: The chemical composition and mass percentage of the steel plate are: C: 0.09%, Si: 0.28%, Mn: 1.75%, P: 0.014%, S: 0.003%, Nb: 0.036%, Ti: 0.037%, Al: 0.032%, and the rest are Fe and other inevitable impurities.

9. The method for producing a thick steel plate for wind power generation with excellent welding performance according to claim 1, characterized in that: The chemical composition and mass percentage of the steel plate are: C: 0.07%, Si: 0.35%, Mn: 1.80%, P: 0.012%, S: 0.002%, Nb: 0.025%, Ti: 0.028%, Al: 0.050%, and the rest are Fe and other inevitable impurities.

10. The method for producing a thick steel plate for wind power generation with excellent welding performance according to claim 1, characterized in that: The chemical composition and mass percentage of the steel plate are: C: 0.12%, Si: 0.50%, Mn: 1.52%, P: 0.010%, S: 0.003%, Nb: 0.030%, Ti: 0.015%, Al: 0.028%, and the rest are Fe and other inevitable impurities.

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