Shell section forge piece with high impact toughness and preparation method of shell section forge piece

Abstract

The invention provides a shell ring forge piece with high impact toughness and a preparation method thereof, and relates to the technical field of forging. By improving the forging ratio of first fire forging, internal gaps of the forge piece can be better pressed in the upsetting process, internal grain structures of the forge piece are crushed to be finer, and the yield of the forge piece is improved. Therefore, the internal structure of the forge piece is improved, the structure defect is eliminated, and the strength and impact toughness of the forge piece are improved. In addition, the heating temperature is properly reduced in the last fire forging process, grains in the forge piece can be effectively prevented from excessively growing, and the impact toughness of the forge piece can be further improved. And finally, the quenching temperature is controlled to be 950-970 DEG C, so that the high strength and the high impact toughness of the shell ring forge piece can be further ensured. In conclusion, the 12Cr2Mo1V shell ring forged piece manufactured through the method has the high strength and the high impact toughness.

Description

Technical Field

[0001] The invention relates to the technical field of forging, and in particular to a barrel section forging with higher impact toughness and a preparation method thereof. Background Art

[0002] The cylinder section is the core component of the hydrogenation reactor of petroleum refining equipment. Its weight can account for up to 95% of the total weight of the entire hydrogenation reactor. Its main function is to support and protect the reactor. Due to the harsh operating conditions of the hydrogenation reactor, its core component, the cylinder section, needs to withstand greater pressure and impact during use. At present, the material of the cylinder section forging is mainly 12Cr2Mo1V steel. In order to meet the ever-increasing use requirements, the 12Cr2Mo1V steel cylinder section forgings are required not only to have higher strength, but also to have higher impact toughness. However, the existing 12Cr2Mo1V steel cylinder section forgings often find it difficult to have both higher strength and higher impact toughness. Summary of the invention

[0003] The problem solved by the invention is how to obtain a 12Cr2Mo1V steel cylinder section forging with higher strength and higher impact toughness.

[0004] In order to solve the above problems, the present invention provides a method for preparing a barrel section forging with high impact toughness, comprising:

[0005] Step S1, cutting off the discarded materials at the nozzle end and the riser end of the steel ingot to obtain a blank; the material of the steel ingot is 12Cr2Mo1V steel;

[0006] Step S2, first fire forging: heating the blank to 1240° C. to 1260° C., heat preservation treatment, and then upsetting and punching to obtain a first intermediate forging; the forging ratio of the first fire forging is 1.50-1.54;

[0007] Step S3, second fire forging: heating the first intermediate forging to 1240° C. to 1260° C., performing heat preservation treatment, and performing mandrel drawing to obtain a second intermediate forging;

[0008] Step S4, third fire forging: heating the second intermediate forging to 1240° C. to 1260° C., heat preservation treatment, and flattening to obtain a third intermediate forging;

[0009] Step S5, fourth fire forging: heating the third intermediate forging to 1240° C. to 1260° C., heat preservation treatment, and expanding the hole by a horse bar to obtain a fourth intermediate forging;

[0010] Step S6, fifth fire forging: heating the third intermediate forging to 1190° C. to 1210° C., performing heat preservation treatment, and performing hole expansion through a rolling mill to obtain a fifth intermediate forging;

[0011] Step S7, performing post-forging heat treatment on the fifth intermediate forging to obtain a cylinder section forging;

[0012] Wherein, in the step S7, the post-forging heat treatment of the fifth intermediate forging to obtain the barrel section forging includes:

[0013] Step S71, quenching treatment: heating the fifth intermediate forging to 650° C. to 700° C. at a first heating rate, keeping the temperature for 6 h to 10 h, then heating to the quenching temperature at a second heating rate, keeping the temperature for 8 h to 10 h, and then water cooling to 90 to 100° C. to obtain a sixth intermediate forging; wherein the quenching temperature is 950° C. to 970° C.;

[0014] Step S72, tempering treatment: heating the sixth intermediate forging to 300°C to 400°C, keeping it warm for 4h to 6h, then heating it to 650°C to 700°C at a third heating rate, keeping it warm for 8h to 10h, and then air-cooling it to room temperature to obtain the barrel section forging.

[0015] Optionally, in step S3, the forging ratio of the second fire forging is 1.50 to 1.90.

[0016] Optionally, in step S4, the forging ratio of the third fire forging is 1.04 to 1.06.

[0017] Optionally, in step S5, the forging ratio of the fourth fire forging is 1.60 to 1.70.

[0018] Optionally, in step S6, the forging ratio of the fifth fire forging is 1.36 to 1.40.

[0019] Optionally, in step S71, the first heating rate is 80°C / h to 100°C / h.

[0020] Optionally, in step S71, the second heating rate is 80°C / h to 100°C / h.

[0021] Optionally, in step S72, the third heating rate is 50°C / h to 70°C / h.

[0022] Optionally, the chemical composition of the 12Cr2Mo1V steel includes, by weight percentage: C: 0.14% to 0.15%; Si: 0 to 0.09%; Mn: 0.50% to 0.60%; P: 0 to 0.005%; S: 0 to 0.003%; Cr: 2.40% to 2.50%; Mo: 1.00% to 1.10%; V: 0.29% to 0.31%; Ni: 0.15% to 0.20%; Cu: 0 to 0.06%; Nb: 0.025%-0.040%; the balance is Fe and unavoidable impurities; and the carbon equivalent CE is greater than 0.98%.

[0023] The present invention also provides a barrel section forging with higher impact toughness, which is prepared by the preparation method of the barrel section forging with higher impact toughness as described above.

[0024] Compared with the related art, the present invention can make the internal voids of the forgings better pressed during the upsetting process by increasing the forging ratio of the first fire forging (1.50 to 1.54), and make the internal grain structure of the forgings broken finer, which is helpful to improve the internal structure of the forgings, eliminate tissue defects, and improve the strength and impact toughness of the forgings. In addition, in the first fire forging to the fourth fire forging process, the heating temperature of the present invention is 1240℃ to 1260℃, and the heating temperature is appropriately reduced (1190℃ to 1210℃) during the last fire forging process, which can effectively prevent the excessive growth of grains in the forgings, which is beneficial to further improve the impact toughness of the forgings. Finally, the present invention quenches and tempers the forgings, and controls the quenching temperature to 950℃ to 970℃, which is beneficial to further ensure that the barrel section forgings have higher strength and higher impact toughness. In summary, the 12Cr2Mo1V barrel section forgings prepared by the method of the present invention have higher strength and higher impact toughness. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of a sample after upsetting in Example 1 of the present invention;

[0026] Figure 2 is a schematic diagram of the first intermediate forging in Example 1 of the present invention;

[0027] Figure 3 is a schematic diagram of the second intermediate forging in Example 1 of the present invention;

[0028] Figure 4 is a schematic diagram of the third intermediate forging in Example 1 of the present invention;

[0029] Figure 5 is a schematic diagram of the fourth intermediate forging in Example 1 of the present invention;

[0030] Figure 6This is a schematic diagram of the fifth intermediate forging in Example 1 of the present invention. DETAILED DESCRIPTION

[0031] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be interpreted as being limited to the embodiments described herein. On the contrary, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0032] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by those skilled in the art to which this application belongs; the terms used in the specification of this application are only for the purpose of describing specific implementation methods and are not intended to limit this application;

[0033] The term "including" and its variations used in this article are open inclusions, that is, "including but not limited to"; the term "based on" is "based at least in part on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first" and "second" mentioned in the present invention are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, the meaning of "multiple" is two or more.

[0034] This embodiment provides a method for preparing a barrel section forging with high impact toughness, comprising:

[0035] Step S1, cutting off the discarded materials at the nozzle end and the riser end of the steel ingot to obtain a blank; the material of the steel ingot is 12Cr2Mo1V steel;

[0036] Step S2, first fire forging: heating the blank to 1240° C. to 1260° C., heat preservation treatment, and then upsetting and punching to obtain a first intermediate forging; the forging ratio of the first fire forging is 1.50 to 1.54;

[0037] Step S3, second fire forging: heating the first intermediate forging to 1240° C. to 1260° C., performing heat preservation treatment, and performing mandrel drawing to obtain a second intermediate forging;

[0038] Step S4, third fire forging: heating the second intermediate forging to 1240° C. to 1260° C., heat preservation treatment, and flattening to obtain a third intermediate forging;

[0039] Step S5, fourth fire forging: heating the third intermediate forging to 1240° C. to 1260° C., heat preservation treatment, and expanding the hole by a horse bar to obtain a fourth intermediate forging;

[0040] Step S6, fifth fire forging: heating the third intermediate forging to 1190° C. to 1210° C., performing heat preservation treatment, and performing hole expansion through a rolling mill to obtain a fifth intermediate forging;

[0041] Step S7, performing post-forging heat treatment on the fifth intermediate forging to obtain a cylinder section forging;

[0042] Wherein, in the step S7, the post-forging heat treatment of the fifth intermediate forging to obtain the barrel section forging includes:

[0043] Step S71, quenching treatment: heating the fifth intermediate forging to 650° C. to 700° C. at a first heating rate, keeping the temperature for 6 h to 10 h, then heating to the quenching temperature at a second heating rate, keeping the temperature for 8 h to 10 h, and then water cooling to 90 to 100° C. to obtain a sixth intermediate forging; wherein the quenching temperature is 950° C. to 970° C.;

[0044] Step S72, tempering treatment: heating the sixth intermediate forging to 300°C to 400°C, keeping it warm for 4h to 6h, then heating it to 650°C to 700°C at a third heating rate, keeping it warm for 8h to 10h, and then air-cooling it to room temperature to obtain the barrel section forging.

[0045] The embodiment of the present invention can make the internal voids of the forgings better pressed during the upsetting process by increasing the forging ratio (1.50 to 1.54) of the first fire forging, and make the internal grain structure of the forgings broken finer, thereby helping to improve the internal structure of the forgings, eliminate tissue defects, and help improve the strength and impact toughness of the forgings. In addition, in the first fire forging to the fourth fire forging process, the heating temperature of the present invention is 1240℃ to 1260℃, and the heating temperature is appropriately reduced (1190℃ to 1210℃) during the last fire forging process, which can effectively prevent the excessive growth of grains in the forgings, which is conducive to further improving the impact toughness of the forgings. Finally, the embodiment of the present invention is conducive to further ensuring that the barrel section forgings have higher strength and higher impact toughness by quenching and tempering the forgings and controlling the quenching temperature to 950℃ to 970℃. In summary, the 12Cr2Mo1V barrel section forgings prepared by the method of the embodiment of the present invention have higher strength and higher impact toughness.

[0046] In some embodiments of the present invention, in step S71, the first heating rate is 80°C / h to 100°C / h, and the second heating rate is 80°C / h to 100°C / h; in step S72, the third heating rate is 50°C / h to 70°C / h.

[0047] In some embodiments of the present invention, in the step S3, the forging ratio of the second fire forging is 1.50 to 1.90; in the step S4, the forging ratio of the third fire forging is 1.04 to 1.06; in the step S5, the forging ratio of the fourth fire forging is 1.60 to 1.70; in the step S6, the forging ratio of the fifth fire forging is 1.36 to 1.40.

[0048] In some embodiments of the present invention, the chemical composition of the 12Cr2Mo1V steel includes, by weight percentage: C: 0.14% to 0.15%; Si: 0 to 0.09%; Mn: 0.50% to 0.60%; P: 0 to 0.005%; S: 0 to 0.003%; Cr: 2.40% to 2.50%; Mo: 1.00% to 1.10%; V: 0.29% to 0.31%; Ni: 0.15% to 0.20%; Cu: 0 to 0.06%; Nb: 0.025%-0.040%; the balance is Fe and unavoidable impurities; and the carbon equivalent CE is greater than 0.98%.

[0049] The selection basis of each component in the 12Cr2Mo1V steel in this embodiment is as follows:

[0050] The C element is a major strengthening element, which directly affects the strength, plasticity and toughness of the forging. When the C content is below 0.8%, the strength and hardness of the forging increase with the increase of the C content. Therefore, in the embodiment of the present invention, the C content is controlled to be 0.14% to 0.15%.

[0051] Mn is a weak carbide-forming element that can improve the strength of steel and does not reduce the plasticity of steel within a certain content range. Mn can form an infinite solid solution with austenite to improve the hardenability of steel. The main use of Mn in this material is to ensure the strength of forgings. Therefore, in the embodiment of the present invention, the content of Mn is controlled to be 0.50% to 0.60%.

[0052] Cr is a carbide-forming element with secondary hardening effect, which can significantly improve the hardness and wear resistance of steel. In quenched and tempered steel, the main function of Cr is to improve the hardenability of forgings, so that the forgings can achieve excellent comprehensive mechanical properties after quenching and tempering. Therefore, in the embodiment of the present invention, the Cr content is controlled to be 2.40% to 2.50%.

[0053] The main function of the Mo element in the material is to improve the hardenability of the material. As the main forgings of the hydrogenation reactor become larger and larger, the wall thickness of the forgings is also getting thicker, which brings certain difficulties to the quenching and tempering. The Mn element in the material can greatly improve the hardenability of the forgings. Therefore, the Mo element content in the embodiment of the present invention is controlled to be 1.00 to 1.10%.

[0054] The V element forms stable and refractory carbides in the material, which enables the steel to maintain a fine grain structure at a higher temperature and greatly reduces the overheating sensitivity of the steel. Therefore, in the embodiment of the present invention, the V element content is controlled to be 0.29% to 0.31%.

[0055] The Ni element is a non-carbide forming element, and its lattice constant is similar to that of austenite. It can form a continuous solid solution with austenite, thereby improving the stability of austenite. The Ni element has a good effect on plasticity and toughness. It can significantly improve the toughness of steel and reduce its ductile-brittle transition temperature while keeping the strength of steel at a high level. For large forgings that require comprehensive mechanical properties, Ni-containing steel is generally selected. When the steel contains elements such as Cr and Mo, the effect of Ni, Cr and Mo on improving hardenability will be significantly higher than that of a single element. Therefore, the role of the Ni element in the material is to improve the plasticity, toughness and hardenability of the forging. In the embodiment of the present invention, the Ni element content is controlled to be 0.15% to 0.20%.

[0056] Experiments have shown that for 12Cr2Mo1V steel, when the carbon equivalent is greater than 0.98%, the impact toughness is higher.

[0057] The embodiment of the present invention further provides a barrel section forging with high impact toughness, which is manufactured by using the method for manufacturing the barrel section forging with high impact toughness as described above.

[0058] The present invention is further described below in conjunction with specific embodiments.

[0059] Example 1

[0060] A1. The discarded materials at the nozzle end and the riser end of the steel ingot are cut off to obtain a billet; the height of the billet is 3120 mm and the diameter is 3150 mm; the material of the steel ingot is 12Cr2Mo1V steel; the chemical composition of the 12Cr2Mo1V steel includes: C: 0.15%; Si: 0.05%; Mn: 0.60%; P: 0.003%; S: 0.002%; Cr: 2.50%; Mo: 1.10%; V: 0.30%; Ni: 0.18%; Cu: 0.03%; Nb: 0.035%; the remainder is Fe and unavoidable impurities.

[0061] A2. First fire forging: heat the billet to 1250°C, keep it warm for 40 hours, and upset it to a height of 2050 mm and a diameter of 3810 mm. Figure 1 As shown, punching is then performed to obtain the first intermediate forging, such as Figure 2 As shown; the inner diameter of the center hole of the first intermediate forging is 1400mm, and the forging ratio of the first fire forging is 1.52.

[0062] A3. Second fire forging: The first intermediate forging is heated to 1250°C, kept at this temperature for 8 hours, and the mandrel is stretched to obtain a second intermediate forging, such as Figure 3 As shown; the inner diameter of the second intermediate forging is 1380mm, the outer diameter is 3030mm, the height is 3750mm, and the forging ratio of the second fire forging is 1.82.

[0063] A4. Third fire forging: The second intermediate forging is heated to 1240°C to 1260°C, kept at this temperature for 6 hours, and leveled to a height of 3550mm to obtain a third intermediate forging, such as Figure 4 As shown; the forging ratio of the third fire forging is 1.05.

[0064] A5. Fourth fire forging: The third intermediate forging is heated to 1250°C, kept at this temperature for 7 hours, and expanded by a horse bar to obtain a fourth intermediate forging, such as Figure 5 As shown; the inner diameter of the fourth intermediate forging is 3200mm, the outer diameter is 4200mm, and the forging ratio of the fourth fire forging is 1.65.

[0065] A6. Fifth fire forging: The third intermediate forging is heated to 1200°C, kept at this temperature for 5 hours, and expanded by a rolling mill to obtain a fifth intermediate forging, such as Figure 6 As shown; the inner diameter of the fifth intermediate forging is 4465mm, the outer diameter is 5185mm, and the height is 3550mm.

[0066] A7, quenching treatment: the fifth intermediate forging is heated to 675°C at a rate of 100°C / h, kept at that temperature for 8 hours, then heated to the quenching temperature at a rate of 100°C / h, kept at that temperature for 8 to 10 hours, and then water-cooled to 90°C to obtain a sixth intermediate forging; wherein the quenching temperature is 960°C;

[0067] A8. Tempering treatment: the sixth intermediate forging is heated to 350° C., kept at this temperature for 5 hours, then heated to 690° C. at a rate of 70° C. / h, kept at this temperature for 10 hours, and then air-cooled to room temperature to obtain the barrel section forging.

[0068] Example 2

[0069] The difference from Example 1 is that, step A6, fifth fire forging: the third intermediate forging is heated to 1190°C, kept warm for 5 hours, and expanded by a rolling mill to obtain a fifth intermediate forging; the inner diameter of the fifth intermediate forging is 4465mm, the outer diameter is 5185mm, and the height is 3550mm.

[0070] Example 3

[0071] The difference from Example 1 is that, step A6, fifth fire forging: the third intermediate forging is heated to 1210°C, kept warm for 5 hours, and expanded by a rolling mill to obtain a fifth intermediate forging; the inner diameter of the fifth intermediate forging is 4465mm, the outer diameter is 5185mm, and the height is 3550mm.

[0072] Comparative Example 1

[0073] The difference from Example 1 is that, step A2, first fire forging: the billet is heated to 1250°C, kept warm for 40 hours, upset to a height of 2400mm and a diameter of 3520mm, and then punched to obtain a first intermediate forging; the inner diameter of the center hole of the first intermediate forging is 1400mm, and the forging ratio of the first fire forging is 1.30. Step A6, fifth fire forging: the third intermediate forging is heated to 1250°C, kept warm for 5 hours, and expanded by a rolling mill to obtain a fifth intermediate forging; the inner diameter of the fifth intermediate forging is 4465mm, the outer diameter is 5185mm, and the height is 3550mm.

[0074] Comparative Example 2

[0075] The difference from Comparative Example 1 is that, step A6, fifth fire forging: the third intermediate forging is heated to 1240°C, kept warm for 5 hours, and expanded by a rolling mill to obtain a fifth intermediate forging; the inner diameter of the fifth intermediate forging is 4465mm, the outer diameter is 5185mm, and the height is 3550mm.

[0076] Comparative Example 3

[0077] The difference from Comparative Example 1 is that, step A6, fifth fire forging: the third intermediate forging is heated to 1260°C, kept warm for 5 hours, and expanded by a rolling mill to obtain a fifth intermediate forging; the inner diameter of the fifth intermediate forging is 4465mm, the outer diameter is 5185mm, and the height is 3550mm.

[0078] Comparative Example 4

[0079] The difference from Example 1 is that in step A7, the quenching temperature is 940°C.

[0080] Comparative Example 5

[0081] The difference from Example 1 is that in step A7, the quenching temperature is 1000°C.

[0082] Experimental example

[0083] The tensile strength and impact toughness of the barrel section forgings prepared in Examples 1 to 3 and Comparative Examples 1 to 5 were tested, and the results are shown in Table 1. Compared with Comparative Examples 1 to 3, the barrel section forgings prepared in Examples 1 to 3 not only have higher strength, but also have higher impact toughness. Compared with Examples 1 to 3, the barrel section forging prepared in Comparative Example 4 has higher impact toughness, but too low strength. Compared with Examples 1 to 3, the barrel section forging prepared in Comparative Example 5 has higher strength, but too low impact toughness. It can be seen that compared with Comparative Examples 1 to 5, the barrel section forging prepared in Example 1 can ensure that both strength and impact toughness are appropriate.

[0084] Table 1

[0085] sample Tensile strength(Mpa) AKv(J) Example 1 651 210 Example 2 654 208 Example 3 656 212 Comparative Example 1 626 182 Comparative Example 2 624 186 Comparative Example 3 627 188 Comparative Example 4 632 212 Comparative Example 5 670 196

[0086] It should be noted that AKv in Table 1 is used to characterize impact toughness, which represents the energy absorbed by the material when subjected to impact load.

[0087] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A method for preparing a barrel section forging with high impact toughness, characterized in that: include: Step S1, cutting off the discarded materials at the nozzle end and the riser end of the steel ingot to obtain a blank; the material of the steel ingot is 12Cr2Mo1V steel; Step S2, first fire forging: heating the blank to 1240° C. to 1260° C., heat preservation treatment, and then upsetting and punching to obtain a first intermediate forging; the forging ratio of the first fire forging is 1.50 to 1.54; Step S3, second fire forging: heating the first intermediate forging to 1240° C. to 1260° C., performing heat preservation treatment, and performing mandrel drawing to obtain a second intermediate forging; Step S4, third fire forging: heating the second intermediate forging to 1240° C. to 1260° C., heat preservation treatment, and flattening to obtain a third intermediate forging; Step S5, fourth fire forging: heating the third intermediate forging to 1240° C. to 1260° C., heat preservation treatment, and expanding the hole by a horse bar to obtain a fourth intermediate forging; Step S6, fifth fire forging: heating the third intermediate forging to 1190° C. to 1210° C., performing heat preservation treatment, and performing hole expansion through a rolling mill to obtain a fifth intermediate forging; Step S7, performing post-forging heat treatment on the fifth intermediate forging to obtain a cylinder section forging; Wherein, in the step S7, the post-forging heat treatment of the fifth intermediate forging to obtain the barrel section forging includes: Step S71, quenching treatment: heating the fifth intermediate forging to 650° C. to 700° C. at a first heating rate, keeping the temperature for 6 h to 10 h, then heating to the quenching temperature at a second heating rate, keeping the temperature for 8 h to 10 h, and then water cooling to 90 to 100° C. to obtain a sixth intermediate forging; wherein the quenching temperature is 950° C. to 970° C.; Step S72, tempering treatment: heating the sixth intermediate forging to 300°C to 400°C, keeping it warm for 4h to 6h, then heating it to 650°C to 700°C at a third heating rate, keeping it warm for 8h to 10h, and then air-cooling it to room temperature to obtain the barrel section forging.

2. The method for preparing a barrel section forging with high impact toughness according to claim 1, characterized in that: In the step S3, the forging ratio of the second fire forging is 1.50 to 1.

90.

3. The method for preparing a barrel section forging with high impact toughness according to claim 1, characterized in that: In the step S4, the forging ratio of the third fire forging is 1.04 to 1.

06.

4. The method for preparing a barrel section forging with high impact toughness according to claim 1, characterized in that: In the step S5, the forging ratio of the fourth fire forging is 1.60 to 1.

70.

5. The method for preparing a barrel section forging with high impact toughness according to claim 1, characterized in that: In the step S6, the forging ratio of the fifth fire forging is 1.36 to 1.

40.

6. The method for preparing a barrel section forging with high impact toughness according to claim 1, characterized in that: In the step S71, the first heating rate is 80°C / h to 100°C / h.

7. The method for preparing a barrel section forging with high impact toughness according to claim 1, characterized in that: In the step S71, the second heating rate is 80°C / h to 100°C / h.

8. The method for preparing a barrel section forging with high impact toughness according to claim 1, characterized in that: In the step S72, the third heating rate is 50°C / h to 70°C / h.

9. The method for preparing a barrel section forging with high impact toughness according to claim 1, characterized in that: The chemical composition of the 12Cr2Mo1V steel includes, by weight percentage, C: 0.14% to 0.15%; Si: 0 to 0.09%; Mn: 0.50% to 0.60%; P: 0 to 0.005%; S: 0 to 0.003%; Cr: 2.40% to 2.50%; Mo: 1.00% to 1.10%; V: 0.29% to 0.31%; Ni: 0.15% to 0.20%; Cu: 0 to 0.06%; Nb: 0.025%-0.040%; the balance is Fe and unavoidable impurities; and the carbon equivalent CE is greater than 0.98%.

10. A barrel section forging with high impact toughness, characterized in that: The barrel section forging with high impact toughness is prepared by the preparation method of any one of claims 1 to 9.

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