Method for producing a 450mpa grade low alloy high toughness hydrogen resistant vessel steel

Abstract

This invention discloses a method for producing 450MPa grade low-alloy high-toughness hydrogen-resistant container steel, including smelting, rolling, quenching heating, quenching cooling, and heat treatment processes; wherein, during the quenching cooling process of the steel plate, the total water volume in the high-pressure section is controlled at 2400-3500 m³ / h. 3 The rolling speed of the steel plate in the high-pressure section is 5-10 m / min. During the smelting process, after strong deoxidation, a large argon gas stirring operation is performed, with an argon gas pressure of 0.3-0.6 MPa. During the rolling process, high-pressure water is applied to the billet before it enters the rolling mill, with a water pressure of 0.2-0.3 MPa and a steel feeding speed of 20-30 m / min. The quenching process adopts segmented heating. After quenching, tempering treatment is performed. The steel plate produced by the above method has an impact absorption energy of ≥100 J at -50℃ in the core, a yield strength of 290-370 MPa, a tensile strength of 460-530 MPa, and good resistance to hydrogen-induced cracking.

Description

Technical Field

[0001] This invention belongs to the field of iron and steel metallurgy technology, specifically relating to a production method of 450MPa grade low alloy high toughness hydrogen-resistant container steel. Background Technology

[0002] To adapt to the gradual depletion of oil and gas resources in recent years, and to address the issue of corrosive media such as H2S and Cl... - With the successive exploitation of oil and gas fields with severely corrosive environments, the service environment for pressure vessel steel has become increasingly harsh. Its shell and welded joints directly bear the physical and chemical effects of corrosive media, including H2S and Cl- in oil and gas. - It is highly corrosive and easily causes corrosion to the base steel plate and joints. As the most widely used and consumed special steel among pressure vessel steels, low alloy pressure vessel steel is difficult to meet the increasingly harsh service environment requirements.

[0003] Meanwhile, most pressure vessel steels are used in environments with extremely low temperatures, or during oil and gas purification and condensation processes, where reaction temperatures are often within extremely low ranges. When the temperature drops below the ductile-brittle transition point, the steel's toughness decreases significantly. To ensure safe equipment operation, petrochemical equipment steels are required to have low ductile-brittle transition temperatures and good low-temperature impact resistance. However, for thick low-alloy pressure vessel steels, due to the large thickness of the steel plate, the core microstructure transformation is incomplete during production, making it difficult to meet the required environmental and operational requirements for low-temperature impact resistance.

[0004] Therefore, there is an urgent need to develop pressure vessel steel that combines mechanical properties and corrosion resistance. This invention patent develops a 450MPa grade low-alloy high-toughness hydrogen-resistant vessel steel by optimizing the steel plate production process. Summary of the Invention

[0005] The technical problem to be solved by the present invention is the production method of 450MPa grade low alloy high toughness hydrogen-resistant container steel.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] A method for producing 450MPa grade low-alloy high-toughness hydrogen-resistant container steel includes smelting, rolling, quenching heating, quenching cooling, and heat treatment processes; wherein, during the quenching cooling process of the steel plate, the total water volume in the high-pressure section is controlled at 2400-3500 m³ / h. 3 / h, the roller speed of the steel plate passing through the high-pressure section is 5-10m / min.

[0008] The total water volume of the high-pressure section described in this invention is achieved by turning on one group of water every 1-2 groups.

[0009] Furthermore, in the steel plate quenching heating process described in this invention, the quenching furnace is heated in two sections: the first section is a high-temperature section with a temperature of 900-920℃, and the second section is a low-temperature section with a temperature of 840-860℃.

[0010] Furthermore, in the rolling process described in this invention, for the first 8-10 passes, high-pressure water is applied to the billet before it enters the rolling mill, with a water pressure of 0.2-0.3 MPa and a steel feeding speed of 20-30 m / min.

[0011] Furthermore, in the smelting process described in this invention, after strong deoxidation, a large argon gas stirring operation is performed, with an argon gas pressure of 0.3-0.6 MPa.

[0012] Furthermore, in the heat treatment process described in this invention, the tempering temperature of the steel plate is 550-650℃.

[0013] Furthermore, the steel plate of the present invention has a thickness of 100-200mm; the steel plate composition (wt%) is: C 0.12-0.18, Si 0.4-0.5, Mn 1.25-1.55, P≤0.015, S≤0.004, Ni≤0.1, Nb≤0.05.

[0014] The steel plate described in this invention conforms to the standard GB / T 713-2014.

[0015] The beneficial effects of adopting the above technical solutions are as follows: During the quenching heating process of steel plates, segmented quenching is used. During the quenching cooling process, the water volume in the high-pressure section and the roller speed of the steel plate passing through the high-pressure section are strictly controlled. This allows the steel plate to generate a certain amount of proeutectoid ferrite under the premise that the alloying elements are fully dissolved. By strictly controlling the heating temperature and cooling rate, the morphology and distribution of proeutectoid ferrite can be precisely controlled, thereby improving the core properties of the steel plate. During the rolling process of steel plates, high-pressure water is applied to the billet before it enters the rolling mill. This allows the surface temperature of the billet to be lower while the core temperature is higher during the rolling process, increasing the core reduction and further refining the core structure. During the billet smelting process, strong deoxidation followed by large-scale argon blowing can further reduce the sulfur content of the steel plate and improve its hydrogen resistance.

[0016] This invention innovates the production process by focusing on the smelting, rolling, and heat treatment steps, thereby improving the mechanical properties and resistance to hydrogen-induced cracking of the steel plate. The steel plate core absorbs ≥100J of impact energy at -50℃, with a yield strength of 290-370MPa and a tensile strength of 460-530MPa. The steel plate exhibits excellent resistance to hydrogen-induced cracking, with a CLR ≤3%, CTR ≤1.0%, and CSR ≤0.3%. This patent only optimizes the production process without adding new equipment or increasing production costs. Detailed Implementation

[0017] The present invention will now be described in further detail with reference to specific embodiments. Example 1

[0018] The steel plate in this embodiment has a thickness of 200mm and a steel plate composition (wt%) of: C 0.18, Si 0.4, Mn 1.25, P 0.015, S 0.004, Ni 0.1, Nb 0.05.

[0019] The steel plate production method in this embodiment includes smelting, rolling, quenching heating, quenching cooling, and heat treatment processes; wherein:

[0020] During the smelting process, after strong deoxidation, a large argon gas stirring operation is carried out with an argon gas pressure of 0.6 MPa.

[0021] During the rolling process, for the first 8 passes, high-pressure water is sprayed on the billet before it enters the rolling mill. The water pressure is 0.3 MPa and the steel feeding speed is 30 m / min.

[0022] During the quenching heating process, the quenching furnace is heated in two sections: the first section is a high-temperature section with a temperature of 920℃, and the second section is a low-temperature section with a temperature of 860℃.

[0023] During the quenching and cooling process, in the high-pressure section of the quenching machine, water is turned on every other set, with the total water volume controlled at 3500m³. 3 / h, the speed of the steel plate passing through the high-pressure section is controlled at 10m / min;

[0024] During heat treatment, the tempering temperature of the steel plate is 650℃.

[0025] The impact energy absorption, tensile properties, and resistance to hydrogen-induced cracking of the steel plate at -50℃ are shown in Table 1. Example 2

[0026] The steel plate in this embodiment has a thickness of 100mm and a steel plate composition (wt%) of: C 0.12, Si 0.5, Mn 1.55, P 0.012, S 0.003, Ni 0.07, and Nb 0.02.

[0027] The steel plate production method in this embodiment includes smelting, rolling, quenching heating, quenching cooling, and heat treatment processes; wherein:

[0028] During the smelting process, after strong deoxidation, a large argon gas stirring operation is carried out with an argon gas pressure of 0.3 MPa.

[0029] During the rolling process, for the first 10 passes, high-pressure water is sprayed on the billet before it enters the rolling mill. The water pressure is 0.2 MPa and the steel feeding speed is 20 m / min.

[0030] During the quenching heating process, the quenching furnace is heated in two sections: the first section is a high-temperature section with a temperature of 900℃, and the second section is a low-temperature section with a temperature of 840℃.

[0031] During the quenching and cooling process, in the high-pressure section of the quenching machine, water is turned on every two sets of equipment, controlling the total water volume at 2400m³. 3 / h; The speed of the steel plate passing through the high-pressure section should be controlled at 5m / min;

[0032] During heat treatment, the tempering temperature of the steel plate is 550℃.

[0033] The impact energy absorption, tensile properties, and resistance to hydrogen-induced cracking of the steel plate at -50℃ are shown in Table 1. Example 3

[0034] The steel plate in this embodiment has a thickness of 154 mm and a steel plate composition (wt%) of: C 0.15, Si 0.42, Mn 1.39, P 0.014, S 0.002, Ni 0.08, and Nb 0.03.

[0035] The steel plate production method in this embodiment includes smelting, rolling, quenching heating, quenching cooling, and heat treatment processes; wherein:

[0036] During the smelting process, after strong deoxidation, a large argon gas stirring operation is carried out with an argon gas pressure of 0.34 MPa.

[0037] During the rolling process, for the first 8 passes, high-pressure water is sprayed on the billet before it enters the rolling mill. The water pressure is 0.23 MPa and the steel feeding speed is 27 m / min.

[0038] During the quenching heating process, the quenching furnace is heated in two sections: the first section is a high-temperature section with a temperature of 912℃, and the second section is a low-temperature section with a temperature of 852℃.

[0039] During the quenching and cooling process, in the high-pressure section of the quenching machine, water is turned on every two sets of equipment, with the total water volume controlled at 2759m³. 3 / h; The speed of the steel plate passing through the high-pressure section should be controlled at 8m / min;

[0040] During heat treatment, the tempering temperature of the steel plate is 590℃.

[0041] The impact energy absorption, tensile properties, and resistance to hydrogen-induced cracking of the steel plate at -50℃ are shown in Table 1. Example 4

[0042] The steel plate in this embodiment has a thickness of 114 mm and a steel plate composition (wt%) of: C 0.14, Si 0.45, Mn 1.29, P 0.011, S 0.003, Ni 0.09, and Nb 0.04.

[0043] The steel plate production method in this embodiment includes smelting, rolling, quenching heating, quenching cooling, and heat treatment processes; wherein:

[0044] During the smelting process, after strong deoxidation, a large argon gas stirring operation is carried out with an argon gas pressure of 0.42 MPa.

[0045] During the rolling process, for the first 8 passes, high-pressure water is applied to the billet before it enters the rolling mill. The water pressure is 0.29 MPa and the steel feeding speed is 24 m / min.

[0046] During the quenching heating process, the quenching furnace is heated in two sections: the first section is a high-temperature section with a temperature of 905℃, and the second section is a low-temperature section with a temperature of 842℃.

[0047] During the quenching and cooling process, in the high-pressure section of the quenching machine, water is turned on every two sets of equipment, with the total water volume controlled at 3021m³. 3 / h; The speed of the steel plate passing through the high-pressure section should be controlled at 6m / min;

[0048] During the heat treatment process, the tempering temperature of the steel plate is 621℃.

[0049] The impact energy absorption, tensile properties, and resistance to hydrogen-induced cracking of the steel plate at -50℃ are shown in Table 1. Example 5

[0050] The steel plate in this embodiment has a thickness of 120mm and a steel plate composition (wt%) of: C 0.16, Si 0.47, Mn 1.42, P 0.010, S 0.004, Ni 0.08, and Nb 0.05.

[0051] The steel plate production method in this embodiment includes smelting, rolling, quenching heating, quenching cooling, and heat treatment processes; wherein:

[0052] During the smelting process, after strong deoxidation, a large argon gas stirring operation is carried out with an argon gas pressure of 0.49 MPa.

[0053] During the rolling process, for the first 9 passes, high-pressure water is sprayed on the billet before it enters the rolling mill. The water pressure is 0.27MPa and the steel feeding speed is 22m / min.

[0054] During the quenching heating process, the quenching furnace is heated in two sections: the first section is a high-temperature section with a temperature of 911℃, and the second section is a low-temperature section with a temperature of 852℃.

[0055] During the quenching and cooling process, in the high-pressure section of the quenching machine, water is turned on every other set, with the total water volume controlled at 2598m³. 3 / h; The speed of the steel plate passing through the high-pressure section is controlled at 9m / min;

[0056] During heat treatment, the tempering temperature of the steel plate is 579℃.

[0057] The impact energy absorption, tensile properties, and resistance to hydrogen-induced cracking of the steel plate at -50℃ are shown in Table 1. Example 6

[0058] The steel plate in this embodiment has a thickness of 129 mm and a steel plate composition (wt%) of: C 0.13, Si 0.48, Mn 1.52, P 0.013, S 0.003, Ni 0.07, and Nb 0.02.

[0059] The steel plate production method in this embodiment includes smelting, rolling, quenching heating, quenching cooling, and heat treatment processes; wherein:

[0060] During the smelting process, after strong deoxidation, a large argon gas stirring operation is carried out with an argon gas pressure of 0.51 MPa.

[0061] During the rolling process, for the first 10 passes, high-pressure water is sprayed on the billet before it enters the rolling mill. The water pressure is 0.24 MPa and the steel feeding speed is 22 m / min.

[0062] During the quenching heating process, the quenching furnace is heated in two sections: the first section is a high-temperature section with a temperature of 903℃, and the second section is a low-temperature section with a temperature of 847℃.

[0063] During the quenching and cooling process, in the high-pressure section of the quenching machine, water is turned on every two sets of equipment, with the total water volume controlled at 3259m³. 3 / h; The speed of the steel plate passing through the high-pressure section should be controlled at 8m / min;

[0064] During heat treatment, the tempering temperature of the steel plate is 624℃.

[0065] The impact energy absorption, tensile properties, and resistance to hydrogen-induced cracking of the steel plate at -50℃ are shown in Table 1. Example 7

[0066] The steel plate in this embodiment has a thickness of 173 mm and a steel plate composition (wt%) of: C 0.17, Si 0.43, Mn 1.34, P 0.013, S 0.002, Ni 0.09, and Nb 0.04.

[0067] The steel plate production method in this embodiment includes smelting, rolling, quenching heating, quenching cooling, and heat treatment processes; wherein:

[0068] During the smelting process, after strong deoxidation, a large argon gas stirring operation is carried out with an argon gas pressure of 0.39 MPa.

[0069] During the rolling process, for the first 9 passes, high-pressure water is applied to the billet before it enters the rolling mill. The water pressure is 0.25 MPa and the steel feeding speed is 28 m / min.

[0070] During the quenching heating process, the quenching furnace is heated in two sections: the first section is a high-temperature section with a temperature of 902℃, and the second section is a low-temperature section with a temperature of 849℃.

[0071] During the quenching and cooling process, in the high-pressure section of the quenching machine, water is turned on every two sets of equipment, with the total water volume controlled at 3218m³.3 / h; The speed of the steel plate passing through the high-pressure section should be controlled at 7m / min;

[0072] During heat treatment, the tempering temperature of the steel plate is 569℃.

[0073] The impact energy absorption, tensile properties, and resistance to hydrogen-induced cracking of the steel plate at -50℃ are shown in Table 1. Example 8

[0074] The steel plate in this embodiment has a thickness of 148mm and a steel plate composition (wt%) of: C 0.15, Si 0.43, Mn 1.31, P 0.011, S 0.003, Ni 0.09, and Nb 0.04.

[0075] The steel plate production method in this embodiment includes smelting, rolling, quenching heating, quenching cooling, and heat treatment processes; wherein:

[0076] During the smelting process, after strong deoxidation, a large argon gas stirring operation is carried out with an argon gas pressure of 0.51 MPa.

[0077] During the rolling process, for the first nine passes, high-pressure water is applied to the billet before it enters the rolling mill. The water pressure is 0.28 MPa and the steel feeding speed is 27 m / min.

[0078] During the quenching heating process, the quenching furnace is heated in two sections: the first section is a high-temperature section with a temperature of 902℃, and the second section is a low-temperature section with a temperature of 849℃.

[0079] During the quenching and cooling process, the water volume in the high-pressure section and the roller speed of the steel plate passing through the high-pressure section must be strictly controlled.

[0080] During the quenching cooling process, the water volume in the high-pressure section of the quenching machine is controlled by turning on one set of water every two sets, maintaining a total water volume of 3018m³. 3 / h;

[0081] During the quenching and cooling process, the speed of the steel plate passing through the high-pressure section is controlled at 7 m / min;

[0082] During heat treatment, the tempering temperature of the steel plate is 608℃.

[0083] The impact energy absorption, tensile properties, and resistance to hydrogen-induced cracking of the steel plates in each embodiment at -50℃ are shown in Table 1.

[0084] Table 1. Steel plate properties of each embodiment

[0085] Serial Number -50℃ Impact Absorbed Energy (J) Yield strength (MPa) Tensile strength (MPa) Hydrogen-induced cracking resistance Example ① 100 290 460 CLR=3%, CTR=1.0%, CSR=0.3% Example ② 159 370 530 CLR=2.9%, CTR=0.6%, CSR=0.2% Example ③ 123 293 489 CLR=2.3%, CTR=0.7%, CSR=0.3% Example 4 148 345 495 CLR=2.6%, CTR=0.7%, CSR=0.2% Example 5 198 321 521 CLR=2.4%, CTR=1.0%, CSR=0.3% Example 6 209 314 485 CLR=2.6%, CTR=0.3%, CSR=0.2% Example ⑦ 124 309 503 CLR=2.4%, CTR=0.4%, CSR=0.1% Example ⑧ 109 356 489 CLR=2.5%, CTR=0.9%, CSR=0.3%

[0086] The above embodiments are only used to illustrate and not limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention without departing from the spirit and scope of the present invention. Any modifications or partial substitutions should be covered within the scope of the claims of the present invention.

Claims

The production method of 1.450MPa grade low-alloy high-toughness hydrogen-resistant container steel includes smelting, rolling, quenching heating, quenching cooling, and heat treatment processes; among which, During the quenching and cooling process of steel plates, the total water volume in the high-pressure section should be controlled at 2400-3500 m³ / h. 3 / h, the roller speed of the steel plate passing through the high-pressure section is 5-10m / min; During the steel plate quenching heating process, the quenching furnace is heated in two sections: one is a high-temperature section with a temperature of 900-920℃, and the other is a low-temperature section with a temperature of 840-860℃. During the rolling process, in the first 8-10 passes, high-pressure water is sprayed on the billet before it enters the rolling mill. The water pressure is 0.2-0.3MPa and the steel feeding speed is 20-30m / min. The steel plate composition (wt%) is as follows: C 0.12-0.18, Si 0.4-0.5, Mn 1.25-1.55, P≤0.015, S≤0.004, Ni≤0.1, Nb≤0.

05.

2. The method for producing 450MPa grade low-alloy high-toughness hydrogen-resistant container steel according to claim 1, characterized in that: During the smelting process, after strong deoxidation, a large argon gas stirring operation is performed with an argon gas pressure of 0.3-0.6 MPa.

3. The method for producing 450MPa grade low-alloy high-toughness hydrogen-resistant container steel according to claim 2, characterized in that: During the heat treatment process, the tempering temperature is 550-650℃.

4. The method for producing 450MPa grade low-alloy high-toughness hydrogen-resistant container steel according to any one of claims 1-3, characterized in that: The thickness of the steel plate is 100-200mm.

5. The method for producing 450MPa grade low-alloy high-toughness hydrogen-resistant container steel according to any one of claims 1-3, characterized in that: The steel plate produced by the method has an impact absorption energy of ≥100J at -50℃ in the core, a yield strength of 290-370MPa, and a tensile strength of 460-530MPa. Resistance of steel plates to hydrogen-induced cracking: CLR≤3%, CTR≤1.0%, CSR≤0.3%.