A CO2 corrosion resistant pipeline steel plate with high crack arrest toughness and a production method thereof

Abstract

The present invention discloses a CO2 corrosion resistant pipeline steel plate with high crack arrest toughness and a production method thereof, wherein the chemical composition is: C: 0.025%-0.055%, Si: 0.15%-0.30%, Mn: 1.35%-1.55%, P≤0.015%, S≤0.002%, Cr: 0.35%-0.65%, Mo: 0.10%-0.20%, Ni+Cu: 0.40%-0.60%, Nb: 0.040%-0.060%, Ti: 0.010%-0.030%, Al: 0.020%-0.050%, and the balance is Fe and unavoidable impurities; the production method thereof comprises billet heating, rolling and accelerated cooling. The present invention obtains a single organization type of granular bainite through the interaction between the elements and with appropriate heating, rolling and cooling processes, and the steel plate of the present invention has both excellent crack arrest toughness and CO2 corrosion resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of metal material production, and in particular to a CO resistant metallurgical material having high crack arrest toughness. 2 Corroded pipeline steel plate and production method thereof. Background Art

[0002] CO 2 Carbon capture, utilization and storage (CCUS) is a new and promising technology for effectively controlling carbon dioxide emissions. Long-distance pipeline transportation is an important part of CCUS technology, in which supercritical CO 2 (Temperature>31℃, pressure>7.4MPa) Pipeline transportation technology has developed rapidly due to its optimal economy.

[0003] Pipeline transportation of supercritical CO 2 If cracks occur in the pipeline, a high stress state will continue to exist at the crack tip, and the crack will continue to expand, leading to long-distance pipeline cracking accidents. During rapid pressure relief, due to the Joule-Thomson effect, the material is exposed to a temperature below the triple point (-56.6°C), and a rapidly propagating ductile fracture occurs at the same time, which requires the pipe to have excellent low-temperature crack arrest performance. In addition, supercritical CO 2 The high-pressure pipeline transportation and high-pressure service conditions also increase the corrosion rate of the pipe. The existing API carbon steel system pipelines used to transport natural gas may leak and fail in the event of occasional corrosion, reducing the service life of the pipe. Although stainless steel pipelines have good corrosion resistance, they are expensive and difficult to apply to long-distance and large-scale CO 2 Therefore, the development of low-alloy carbon steel pipes with high crack arrest toughness and good corrosion resistance is the key to achieving supercritical CO 2 The key to safe long-distance pipeline transportation.

[0004] The invention patent with publication number CN202110097162.1 discloses a CO2-resistant 2 Steel plate for corrosion and preparation method. Its chemical composition is: C: 0.03%-0.07%, Cr: 4.0%-6.0%, Ni: 0.15%-2.50%, Nb: 0.01%-0.06%, P≤0.005%, S≤0.005%, and the rest is Fe and inevitable impurity elements. The Cr content in its chemical composition reaches more than 4%, and the corrosion resistance is enhanced by relying on the high content of Cr element. The production method adopts controlled rolling and controlled cooling + quenching and tempering heat treatment process.

[0005] The invention patent with publication number CN202211192415.4 discloses a low Cr content CO resistant 2Corrosion oil casing and preparation method thereof. Its chemical composition is: C: 0.21%-0.29%, Si: 0.25%-0.45%, Mn: 0.90%-1.10%, Cr: 2.95%-5.50%, Mo: 0.35%-0.50%, Ni: 0.15%-0.25%, Cu: 0.15%-0.25%, Nb: 0.05%-0.08%, Ti: 0.02%-0.05%, N: 0.001%-0.010%, Ce: 0.006%-0.010%, Al: 0.005%-0.020%, Ca: 0.005%-0.010%, P≤0.015%, S≤0.005%, O≤0.002%, H≤0.00015%, and the balance is Fe and unavoidable impurities. Its chemical composition contains 0.21%-0.29% of C element, 2.95%-5.50% of Cr element and 0.006%-0.010% of Ce element, and the product is a seamless pipe for oil casing, which is produced through hot perforation, hot continuous rolling and heat treatment processes.

[0006] The invention patent with the publication number CN02137308.6 discloses a low alloy steel for resisting carbon dioxide and hydrogen sulfide corrosion. Its chemical composition is: C: 0.15%-0.30%, Si: 0.01%-1.0%, Mn: 0.10%-2.0%, Cr: 0.50%-3.0%, Mo: 0.01%-1.0%, Ce: 0.005%-0.25%, V: 0.005%-0.1%, Cu: 0.05%-1.02%, Al: 0.01%-0.10%, a small amount of Nb and other elements are added when necessary, and the balance is iron and other inevitable impurities. Its chemical composition contains 0.15%-0.30% C element, 0.005%-0.25% Ce element and 0.005%-0.1% V element, and the product is a seamless pipe for oil well pipe, and the organizational type is troostite.

[0007] The invention patent with publication number CN201310217916.8 discloses a CO2-resistant gas generator for ground gathering and transmission. 2Preparation method of corrosion pipeline steel. Its chemical composition is: C: 0.01%-0.08%, Si: 0.10%-0.50%, Mn: 0.50%-1.50%, P≤0.02%, S≤0.006%, Nb+V+Ti≤0.1%, Cr: 1.0%-3.0%, Mo: 0.10%-0.30%, Cu: 0.10%-0.50%, Ni: 0.10%-0.50%, the remainder is Fe and inevitable impurities. Its chemical composition contains V element and 1.0%-3.0% Cr element, and the corrosion resistance is enhanced by the high content of Cr element. The metallographic structure is a complex phase structure of acicular ferrite and granular bainite. In addition, the service condition of the steel plate described in the invention is an oil and gas transportation environment with a total gas pressure of normal pressure.

[0008] The invention patent with publication number CN202010105910.1 discloses an 8-15mm thick corrosion-resistant and high crack arrest submarine pipeline steel X65MO and its production method. Its chemical composition is: C: 0.05%-0.08%, Si: 0.10%-0.20%, Mn: 1.00%-1.20%, P≤0.015%, S≤0.002%, Nb: 0.025%-0.035%, Ti: 0.015%-0.025%, Cr: 0.15%-0.25%, Ce: 0.0010%-0.0020%, H≤2.0ppm, O≤30ppm, N≤60ppm, and the rest is Fe and unavoidable impurities. Its chemical composition contains 1.00%-1.20% Mn and 0.0010%-0.0020% Ce. The product is a steel coil with a thickness of 8-15mm. The metallographic structure is a dual-phase structure of polygonal ferrite and acicular ferrite. The finished product has H resistance. 2 S corrosion resistance, and no CO resistance 2 Corrosion properties.

[0009] The invention patent with publication number CN200410066297.8 discloses an acicular ferrite X70 pipeline steel with high crack arrest toughness and a manufacturing method thereof. Its chemical composition is: C: 0.020%-0.060%, Mn: 1.45%-1.75%, Si: 0.100%-0.500%, S≤0.0020%, P: 0.004%-0.012%, Nb: 0.050%-0.080%, Ti: 0.005%-0.025%, V: 0.010%-0.060%, Mo: 0.10%-0.30%, Ca: 0.0015%-0.0040%, N≤0.0080%, Al: 0.015%-0.045%. Its chemical composition contains 0.010%-0.060% V and no Cr. Its organizational characteristics are acicular ferrite. In addition, it does not involve CO resistance. 2Corrosion properties.

[0010] The invention patent with publication number CN201710196157.X discloses a high-strength thick steel plate with excellent crack arrestability and a manufacturing method thereof. Its chemical composition is: C: 0.04%-0.16%, Si: 0.1%-0.5%, Mn: 0.9%-1.6%, Cu: 0.1%-0.3%, Ni: 0.2%-0.9%, P≤0.02%, S≤0.02%, Als: 0.01%-0.05%, N: 0.002-0.010%, Nb: 0.02%-0.05%, Ti: 0.01%-0.03%, and the rest is Fe and unavoidable impurities. Its chemical composition does not contain Mo and Cr elements. Its production process adopts low-temperature heating, low-temperature rolling and low-temperature cooling. The maximum heating temperature does not exceed 1150℃, the final rolling temperature does not exceed 760℃, the cooling temperature does not exceed 400℃, and it needs to be slowly cooled for 24 hours. In addition, its finished product is container ship steel with a thickness of 50-90mm, and does not involve CO2 resistance. 2 Corrosion properties.

[0011] The invention patent with publication number EP3239330B1 discloses a high-strength steel with excellent brittle crack arrest and its production method. Its chemical composition is: C: 0.05%-0.1%, Mn: 0.9%-1.5%, Ni: 0.8%-1.5%, Nb: 0.005%-0.1%, Ti: 0.005%-0.1%, Cu: 0.1%-0.6%, Si: 0.1%-0.4%, P≤100ppm, S≤40ppm, and the rest is Fe and unavoidable impurities. Its chemical composition has a high Ni content and does not contain Mo and Cr elements; its production process adopts low-temperature heating, the maximum heating temperature does not exceed 1100℃, and the steel plate cooling temperature does not exceed 700℃. In addition, its finished product does not involve CO resistance. 2 Corrosion properties.

[0012] The invention patent with publication number WO2021109439A1 discloses a pipeline steel with both HIC resistance and large deformation resistance and its manufacturing method. Its chemical composition is: C: 0.015%-0.039%, Si: 0.15%-0.35%, Mn: 1.6%-1.9%, S≤0.002%, P≤0.012%, Al: 0.02-0.045%, Cr: 0.15%-0.35%, 0.05≤Nb+V+Ti≤0.1%, Nb, V, Ti are not 0, Ni: 0.15%-0.50%, Cu: 0.01%-0.25%, Ca≤0.002%, N≤0.0046%, Mo: 0.01%-0.20%, and the rest is Fe and unavoidable impurities. Its chemical composition has a high Mn content. Although its organizational characteristics are bainite single-phase organization, its production process uses relatively low heating temperature and final cooling temperature. The maximum heating temperature does not exceed 1160℃, and the final cooling temperature is below 280℃. In addition, its finished product has H resistance. 2 S corrosion resistance, and no CO resistance 2 Corrosion properties.

[0013] In summary, the current CO 2 The main problems of corroded steel plates are as follows:

[0014] CO resistant 2 The Cr content in the corrosion resistance components is high, and the corrosion resistance of steel is improved by relying on a high content of Cr elements. In addition, the crack arrest toughness of steel is not mentioned, and no special scheme is designed to improve the crack arrest toughness of steel. However, pipeline steel with high crack arrest toughness does not involve CO resistance. 2 Corrosion resistance, not resistant to CO 2 In addition, the transport medium and material service conditions are low CO 2 The oil and gas field environment does not involve the transportation of supercritical CO 2 High pressure service environment. Summary of the invention

[0015] In view of the above problems and shortcomings, the object of the present invention is to provide a CO resistant 2 Corrosion pipeline steel plate and its production method, through the steel plate composition design, production and manufacturing process and microstructure control, obtain ideal internal quality, reduce harmful elements and impurities, and effectively improve the organizational structure and grain size of the steel plate. Relying on appropriate processes to refine and control the microstructure, ensure the excellent crack arrest toughness and CO resistance of the steel plate 2 Comprehensive corrosion performance.

[0016] In order to achieve the above object, the technical solution of the present invention is as follows:

[0017] The present invention provides a CO resistant composite material with high crack arrest toughness. 2 Corrosion pipeline steel plate, the chemical composition of the steel plate, according to weight percentage: C: 0.025%-0.055%, Si: 0.15%-0.30%, Mn: 1.35%-1.55%, P≤0.015%, S≤0.002%, Cr: 0.35%-0.65%, Mo: 0.10%-0.20%, Ni+Cu: 0.40%-0.60%, Nb: 0.040%-0.060%, Ti: 0.010%-0.030%, Al: 0.020%-0.050%, and the balance is Fe and unavoidable impurities.

[0018] In the above technical solution, further, in terms of weight percentage, Ni / Cu≥0.6.

[0019] The composition design reasons of the present invention are as follows:

[0020] C: The most basic and economical strengthening element in steel. A high C content easily causes central segregation in the steel plate, which is detrimental to the corrosion resistance and crack arrest toughness of the steel. Therefore, the present invention controls the C content to be within the range of 0.025%-0.055%.

[0021] Si: can improve the strength of steel plates through solid solution strengthening, and has the effect of improving the hardenability and corrosion resistance of the material. Among all alloy elements, Si is abundant in resources and relatively cheap in cost. Adding an appropriate amount of Si to steel can also inhibit the precipitation of cementite. At the same time, Si will be enriched around carbides, hindering the growth of carbides, causing carbides to become small and dispersed in the matrix, which is beneficial to improving strength. However, a higher content of Si makes steel tend to graphitize, making the steel brittle, reducing plasticity, and deteriorating toughness. The content of Si in the present invention is controlled at 0.15-0.30%.

[0022] Mn: It is a common strengthening element in steel and can be dissolved in the Fe matrix in large quantities to improve strength through solid solution strengthening. Manganese can reduce the critical cooling rate of steel, greatly improve hardenability, and significantly reduce the brittle transition temperature of steel, improve impact toughness, and refine the microstructure of steel. It is an important strengthening element. However, if the Mn content is too high, it is easy to form segregation in the steel, which has an adverse effect on the plasticity, toughness and corrosion resistance of the steel. Taking all factors into consideration, the present invention controls the range of Mn to be 1.35%-1.55%.

[0023] Cr: It can improve the hardenability of steel, strengthen the cooling effect of steel plates, improve the uniformity of the structure in the thickness direction, and make up for the strength loss of steel plates caused by low C and low Mn. The price of Cr alloy is not high. It can not only replace precious metal elements such as Mo and V that play a strengthening role to reduce the alloy cost, but also the hardenability effect is not as strong as Mo under similar content conditions. The right amount of Cr can more stably control the formation of medium-temperature transformation structure-granular bainite. However, a higher content of Cr will make the hardenability of steel too high, form too much hardenable structure, make the lamellar structure of the structure obvious, and deteriorate the crack arrest toughness of the steel plate. Taking all factors into consideration, the range of Cr controlled by the present invention is 0.35%-0.65%.

[0024] Mo: It can improve the hardenability of steel, has a certain grain refinement effect, can effectively improve the strength of steel, promote medium and low temperature microstructure transformation and inhibit ferrite transformation, and can improve the corrosion resistance of steel plates when combined with elements such as Ni and Cu. The price of Mo is relatively high. Excessive addition will lead to a significant increase in alloy cost on the one hand, and on the other hand, it will also make the hardenability too strong, promote the formation of a large number of lath-shaped shear-type microstructures, and is not conducive to the improvement of crack arrest performance. The present invention controls the range of Mo to be 0.10%-0.20%.

[0025] Ni, Cu: Ni can improve the strength of steel, reduce the critical cooling temperature, delay pearlite transformation, facilitate microstructure control and grain refinement, and improve low-temperature toughness. Adding Cu in appropriate amounts can improve the strength, low-temperature toughness and corrosion resistance of steel. However, excessive Cu content can easily cause embrittlement of the steel plate, produce thermal cracks, and reduce toughness. Due to the high price of Ni, it is not advisable to add too much. The composite addition of Ni and Cu can fully play their respective beneficial roles. The present invention controls Ni / Cu to be not less than 0.6, and the range of Ni+Cu is 0.40%-0.60%.

[0026] Nb: Grain refining element. When heated, the carbon and nitride particles of Nb that are not dissolved are distributed on the austenite grain boundaries, which can hinder the growth of austenite grains when the steel is heated, and can effectively delay the recrystallization of deformed austenite, play a role in refining grains, improve the strength and toughness of steel and reduce its brittle transition temperature. The present invention controls the range of Nb to be 0.040%-0.060%.

[0027] Ti: It is a strong N-fixing element. Adding a small amount of Ti to Al-containing steel can significantly reduce the corrosion rate. Ti can preferentially combine with N in the steel, reduce the amount of AlN in the steel, and improve weldability. However, when the Ti content exceeds a certain value, the TiN particles will coarsen, causing the low-temperature toughness to deteriorate. Therefore, the Ti content of the present invention is selected to be 0.010%-0.030%.

[0028] Al: It is usually used as a deoxidizer in steel. If the aluminum content is too low, deoxidation is insufficient and easily oxidized elements such as Ti will form oxides; if the aluminum content is too high, aluminum oxide inclusions will increase, reducing the cleanliness of the steel. Therefore, the present invention controls the range of Al to be 0.020%-0.050%.

[0029] P, S: As impurity elements, P and S significantly deteriorate the toughness, plasticity and weldability of steel, so the content of P and S in steel should be reduced as much as possible. In the present invention, the P and S contents are required to be controlled within P≤0.015% and S≤0.002%, respectively.

[0030] In the above technical solution, further, the yield strength of the steel plate is 470-570MPa, the tensile strength is 550-640MPa, the average impact energy of the steel plate at -60°C is ≥250J, and the average DWTT at -30°C is ≥90%.

[0031] In the above technical solution, further, the final structure of the steel plate is a single granular bainite structure, and the average crystal grain size of the bainite is ≤8 μm.

[0032] In the above technical solution, further, the thickness of the finished steel plate is 15-25 mm.

[0033] Another aspect of the present invention provides a CO resistant material having high crack arrest toughness. 2 A method for producing corroded pipeline steel plates, including billet heating, rolling and accelerated cooling;

[0034] Billet heating: The billet heating temperature is 1160-1220℃, and the holding time is not less than 120min;

[0035] The design of the heating process is mainly to ensure the full solid solution of elements such as Mn, Cr, Ni, Cu, Nb, etc., so that they can play a role in the subsequent rolling and accelerated cooling, and at the same time, effectively control the growth of austenite grains; the heating time can ensure the heating effect and temperature uniformity;

[0036] Rolling: The billet is rolled directly after it comes out of the furnace, and a three-stage rolling process is adopted, in which the rough rolling is carried out in two stages. The first stage rolling end temperature is ≥1100℃, and then air cooling is carried out to wait for the temperature. The second stage starts the rolling temperature at 1060-1080℃, and the single pass reduction rate of the last two passes before the end of rolling is ≥16%. The third stage is finishing rolling, and the finishing rolling start temperature is 870-920℃. The single pass reduction rate of the first three passes is ≥14%, and the final rolling temperature is Ar 3 +60℃-Ar 3 +90℃;

[0037] The process design of two-stage rough rolling can make the original austenite grains fully broken and refined, especially the second stage is rolling deformation at a relatively low temperature, which can effectively reduce the driving force of austenite grain growth and inhibit excessive grain growth; the design of the finishing rolling process can, on the one hand, ensure that the austenite is fully flattened and deformed and accumulates deformation energy, and on the other hand, it can promote the induction of precipitation of fine Nb precipitates, pin grain boundaries and dislocations, increase nucleation positions, and further refine grains.

[0038] Accelerated cooling: After the steel plate is rolled, it is accelerated to cool. The accelerated cooling is carried out in two stages. The first stage starts cooling at a temperature range of Ar. 3 +30℃-Ar 3 +60℃, cooling rate is 25-30℃ / s, cooling time is 5-8s, the second stage of cooling is carried out directly after the first stage of cooling, the second stage of cooling rate is 8-12℃ / s, and the final cooling temperature is M s +30℃-M s +80℃;

[0039] The purpose of the first stage cooling process is to inhibit the transformation of austenite to ferrite and obtain bainite structure at a faster cooling rate. The purpose of the second stage cooling is to control the organizational type of bainite transformation, inhibit the formation of coarse lath-like organization, promote the formation of fine irregular blocky organization, and finally obtain a single type of granular bainite organization with an average grain size of ≤8μm. The irregular organizational structure of granular bainite causes the crack propagation path of the steel plate to turn along the irregular grain boundary when cracking occurs, consumes the energy of crack propagation, significantly reduces the crack driving force, and achieves effective crack arrest. The single type of organization makes the steel plate 2 Uniform corrosion occurs in the environment, forming a corrosion passivation film attached to the surface of the steel plate; due to the single and evenly distributed tissue type, the corrosion conditions at various locations on the surface of the steel plate are the same, and local corrosion is not easy to occur; the formed corrosion passivation film can effectively hinder the further occurrence of corrosion, significantly reduce the corrosion rate, and play a good corrosion resistance role.

[0040] In the above technical solution, further, the thickness of the intermediate billet after rough rolling is 3.3-4.2t, wherein t is the thickness of the finished steel plate.

[0041] In the above technical solution, further, in the rolling process, the finishing rolling temperature is 820-850°C.

[0042] In the above technical solution, further, in the accelerated cooling process, the first stage start cooling temperature is 790-820°C, and the second stage final cooling temperature is 490-550°C.

[0043] The beneficial effects of the present invention are:

[0044] The present invention uses cheap elements such as C, Mn, Cr, Cu and trace amounts of Nb and Ni, and finally obtains a single organizational type of granular bainite through the interaction between the elements and appropriate heating, rolling and cooling processes. 2 Compared with conventional steel and its production technology, the present invention has the advantages of crack toughness and CO resistance. 2 The microstructure design is targeted to improve the corrosion performance, and the steel plate produced has excellent crack arrest toughness and CO resistance. 2 Corrosion properties.

[0045] The steel plate of the present invention has a yield strength of 470-570MPa, a tensile strength of 550-640MPa, and a strength of X65 level. The steel plate has an average impact energy of ≥250J at -60℃ and an average DWTT of ≥90% at -30℃. 2 The uniform corrosion rate in the environment is ≤0.07mm / a, and all performances meet the requirements for manufacturing supercritical CO 2 Technical requirements for X65 grade steel plates for pipeline transportation. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is a metallographic structure photograph of the steel in Example 5 of the present invention;

[0047] Figure 2 This is the SEM image of the steel in Example 5 of the present invention. DETAILED DESCRIPTION

[0048] The following examples are only some of the best embodiments of the present invention and do not limit the scope of the above invention and technical means.

[0049] Smelting was carried out according to the designed chemical composition range. The chemical compositions of the steels of Examples 1-9 and Comparative Examples 1-5 are shown in Table 1.

[0050] Table 1 Chemical composition of steels of the present invention and comparative examples (wt%)

[0051]

[0052]

[0053] The obtained molten steel is cast to obtain a billet, and the billet is heated-rolled-accelerated cooled to obtain the steel plate of the present invention;

[0054] The billet heating, rolling and accelerated cooling processes of Examples 1-9 and Comparative Examples 1-5 are shown in Tables 2 to 4.

[0055] Table 2 Billet heating process of the steel of the present invention and the comparative example

[0056] serial number Blank thickness / mm Heating temperature / ℃ Insulation time / min Example 1 250 1170-1200 133 Example 2 250 1160-1190 120 Example 3 250 1190-1220 139 Example 4 300 1160-1190 168 Example 5 300 1180-1210 125 Example 6 300 1170-1200 146 Example 7 300 1190-1220 140 Example 8 300 1180-1210 159 Example 9 300 1160-1190 152 Comparative Example 1 200 1200 90 Comparative Example 2 250 1200 120 Comparative Example 3 250 1190-1240 210-300 Comparative Example 4 250 1201 130 Comparative Example 5 300 1180 150

[0057] Table 3 Rolling process of the steel of the present invention and the comparative example

[0058]

[0059]

[0060] Table 4 Accelerated cooling process of the steel of the present invention and the comparative example

[0061]

[0062]

[0063] Conventional mechanical property tests and organizational characteristic tests were performed on the steels of Examples 1-9 of the present invention and Comparative Examples 1-5. The results are shown in Tables 5 and 6.

[0064] Table 5 Tensile properties of the steels of the embodiments of the present invention and the comparative examples

[0065]

[0066] Table 6 CO resistance of the steels of the embodiments of the present invention and the comparative examples 2 Corrosion performance and structural characteristics

[0067]

[0068]

[0069] Note: Corrosion test conditions: test temperature 40℃, pressure 10MPa, corrosive medium is supercritical CO 2 .

[0070] The above embodiments are only preferred embodiments of the present invention and are not intended to limit the implementation methods. The protection scope of the present invention shall be subject to the scope defined in the claims. Other different forms of changes or modifications may be made based on the above description. Obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A CO2 corrosion resistant pipeline steel plate with high crack arrest toughness, characterized in that: The chemical composition of the steel plate is as follows by weight percentage: C: 0.025%-0.055%, Si: 0.15%-0.30%, Mn: 1.35%-1.55%, P≤0.015%, S≤0.002%, Cr: 0.35%-0.65%, Mo: 0.10%-0.20%, Ni+Cu: 0.40%-0.60%, Nb: 0.040%-0.060%, Ti: 0.010%-0.030%, Al: 0.020%-0.050%, and the balance is Fe and unavoidable impurities; The production method of the steel plate includes billet heating, rolling and accelerated cooling; wherein: Billet heating: The billet heating temperature is 1160-1220℃, and the holding time is not less than 120min; Rolling: The billet is rolled directly after it comes out of the furnace, and a three-stage rolling process is adopted, in which the rough rolling is carried out in two stages. The first stage rolling end temperature is ≥1100℃, and then air cooling is carried out to wait for the temperature. The second stage starts the rolling temperature at 1060-1080℃, and the single pass reduction rate of the last two passes before the end of rolling is ≥16%. The third stage is finishing rolling, and the finishing rolling start temperature is 870-920℃, the single pass reduction rate of the first three passes is ≥14%, and the final rolling temperature is Ar3+60℃-Ar3+90℃; Accelerated cooling: After the steel plate is rolled, it is accelerated to cool. The accelerated cooling is carried out in two stages. The first stage cooling temperature is Ar3+30℃-Ar3+60℃, the cooling rate is 25-30℃ / s, and the cooling time is 5-8s. After the first stage cooling, the second stage cooling is carried out directly, the cooling rate is 8-12℃ / s, and the final cooling temperature is M s +30℃-M s +80℃.

2. The CO2 corrosion resistant pipeline steel plate with high crack arrest toughness according to claim 1, characterized in that: In terms of weight percentage, Ni / Cu≥0.

6.

3. The CO2 corrosion resistant pipeline steel plate with high crack arrest toughness according to claim 1, characterized in that: The yield strength of the steel plate is 470-570 MPa, the tensile strength is 550-640 MPa, the average impact energy of the steel plate at -60°C is ≥250 J, and the average DWTT at -30°C is ≥90%.

4. The CO2 corrosion resistant pipeline steel plate with high crack arrest toughness according to claim 1, characterized in that: The final structure of the steel plate is a single granular bainite structure, and the average crystal grain size of the bainite is ≤8 μm.

5. The CO2 corrosion resistant pipeline steel plate with high crack arrest toughness according to claim 1, characterized in that: The thickness of the finished steel plate is 15-25mm.

6. The CO2 corrosion resistant pipeline steel plate with high crack arrest toughness according to claim 1, characterized in that: In the rolling process, the thickness of the intermediate billet after rough rolling is (3.3-4.2)t, where t is the thickness of the finished steel plate.

7. The CO2 corrosion resistant pipeline steel plate with high crack arrest toughness according to claim 1, characterized in that: In the rolling process, the finishing temperature is 820-850℃.

8. The CO2 corrosion resistant pipeline steel plate with high crack arrest toughness according to claim 1, characterized in that: In the accelerated cooling process, the first stage of cooling is 790-820°C, and the second stage of final cooling is 490-550°C.

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