1Cr13 bar for nuclear power and manufacturing method thereof

Abstract

The invention relates to the technical field of pipe preparation, and particularly discloses a 1Cr13 bar for nuclear power and a manufacturing method of the 1Cr13 bar. According to the manufacturing method of the 1Cr13 bar for nuclear power, the content of C, N and Ni elements is controlled, formation of ferrite is reduced, a good foundation is laid for follow-up heat treatment, the ferrite is fully converted into tempered martensite by controlling the heat treatment process, the content of the ferrite in the structure is smaller than or equal to 1%, the strength and toughness of the material are effectively improved, and the service life of the material is prolonged. The method provides firm and reliable material support for efficient and safe operation of a nuclear power station, is particularly suitable for manufacturing parts such as a driving rod piece, a valve seat and a fastener of a driving mechanism for the nuclear power station, and has high practical value.

Description

Technical Field

[0001] The invention relates to the technical field of tube preparation, and in particular to a 1Cr13 rod for nuclear power and a manufacturing method thereof. Background Art

[0002] With the adjustment of the global energy structure, nuclear power, as a clean, efficient and stable energy form, occupies an increasingly important position in the energy supply system. The construction and operation of nuclear power plants have extremely high requirements for safety and reliability. The material performance of key components in nuclear reactors directly affects the safe and stable operation of the entire nuclear power plant.

[0003] 1Cr13 stainless steel has been widely used in nuclear power equipment because of its certain strength, corrosion resistance and relatively good comprehensive mechanical properties. 1Cr13 steel is a semi-martensitic stainless steel. Usually, the ferrite content is about 40%. The ferrite in the steel will lead to a greater cold brittle tendency, making it have a higher yield strength and lower plasticity at room temperature. However, the high temperature strength and low temperature toughness are not ideal, and cannot meet the use requirements of nuclear power equipment. At the same time, the uneven distribution of ferrite will also affect the uniformity of the mechanical properties of the material, causing local stress concentration in the components during long-term operation, accelerating fatigue damage and failure of the components.

[0004] At present, conventional 1Cr13 bars mainly reduce the ferrite content by controlling the composition and increasing the forging ratio. However, the ferrite content in the steel can only be reduced to a minimum of about 10%, which can reduce the cold brittleness tendency of the steel to a certain extent and slightly improve the high temperature performance and low temperature toughness of the steel. However, it still cannot meet the use requirements for some nuclear power equipment with high performance requirements. Therefore, a new manufacturing method of 1Cr13 bars with ultra-low ferrite content for nuclear power is urgently needed to solve the defects of the existing manufacturing process in controlling the ferrite content, meet the growing demand for high-performance 1Cr13 bars in the nuclear power field, and ensure the safe and reliable operation of nuclear power plants. Summary of the invention

[0005] Aiming at the problems that the existing preparation process of 1Cr13 rod cannot effectively reduce the ferrite content, resulting in the inability to effectively improve the low-temperature toughness and high-temperature strength, the present invention provides a 1Cr13 rod for nuclear power and a manufacturing method thereof.

[0006] To solve the above technical problems, the technical solution provided by the embodiment of the present invention is:

[0007] A method for manufacturing 1Cr13 bars for nuclear power, comprising the following steps:

[0008] S1, the raw materials are subjected to arc furnace smelting, AOD refining and LF refining to obtain molten steel with a C content of 0.12% to 0.14% and a Ni content of 0.4% to 0.5%; the molten steel is then subjected to VD vacuum degassing, nitrogen is introduced to control the N content in the molten steel to be 0.02% to 0.04%, and casting is performed to obtain a steel ingot;

[0009] S2, electroslag remelting the steel ingot under a protective atmosphere, cooling the steel ingot to obtain an electroslag ingot;

[0010] S3, heating and forging the electroslag ingot, and then annealing it to obtain a forged steel billet;

[0011] S4, grinding the forged steel billet, heating and rolling it, slowly cooling it to room temperature, and annealing it to obtain a rolled steel billet;

[0012] S5, the rolled steel billet is first heated to 980°C-1000°C and kept warm, then air-cooled to room temperature; then heated to 940°C-960°C and kept warm, then oil-cooled to below 80°C; finally heated to 740°C-760°C and kept warm, then air-cooled to room temperature, and straightened to obtain a method for manufacturing 1Cr13 bars for nuclear power.

[0013] Compared with the prior art, the manufacturing method of 1Cr13 rod for nuclear power provided by the present invention can effectively inhibit the precipitation of ferrite during solidification and cooling and inhibit the transformation of the structure to ferrite without significantly increasing the hardness of the material by controlling the content of C, N and Ni elements, thereby significantly reducing the ferrite content in the steel (ferrite content ≤ 1%); at the same time, controlling the N content to 0.015% to 0.035%, which can also refine the grains to a certain extent and further improve the toughness of the material; controlling the Ni content to 0.3% to 0.5% is conducive to obtaining an ideal martensitic structure under a heat treatment process; finally, the rolled steel billet is subjected to normalizing treatment (980°C to 1000°C) to convert the ferrite into pearlite and refine it, and then through quenching (940°C to 960°C) and tempering treatment (740°C to 760°C), the refined pearlite structure is converted into tempered martensite, and no new ferrite is generated in the steel during the treatment process. The present invention can effectively improve the key properties of 1Cr13 in nuclear power applications, such as low-temperature toughness and high-temperature strength, by strictly controlling the contents of C, N, and Ni and optimizing the heat treatment process, effectively solving the difficult problem of high-performance material requirements for nuclear power equipment under complex and harsh working conditions, and providing a solid material guarantee foundation for the safe and efficient operation of nuclear power plants.

[0014] It should be noted that the processes of electric furnace smelting, AOD refining, LF refining, VD vacuum degassing, etc. described in the present invention are all existing technologies, and the conventional processes of the existing 1Cr13 process can be adopted. It is only necessary to control the C, N, and Ni contents in the above processes within the range specified by the present invention.

[0015] Furthermore, in S2, the cooling is performed by hood cooling, and the hood cooling time is 24h to 48h.

[0016] Furthermore, in S3, the heating temperature is 1130° C. to 1150° C., and the insulation time is 3 h to 5 h.

[0017] The optimal heating temperature and holding time are beneficial to improving the uniformity of the steel billet structure after forging, thereby improving the toughness and strength of the material.

[0018] Furthermore, in S3, the forging ratio of the forging is 10-11.

[0019] It should be noted that the forging process in the present invention is a prior art, and the conventional process of existing 1Cr13 steel can be adopted, and the present invention does not make any special limitation.

[0020] Furthermore, in S3, the annealing temperature is 820° C. to 870° C., and the annealing holding time is 12 h to 24 h.

[0021] The ferrite produced within the above annealing temperature range is all α-ferrite, which is beneficial to transform the α-ferrite structure into pearlite in the normalizing treatment of the subsequent heat treatment, thereby improving the structural uniformity and performance of the material.

[0022] Furthermore, in S4, the heating temperature is 1130° C. to 1150° C., and the insulation time is 1 h to 1.5 h.

[0023] The preferred heating temperature can provide ideal conditions for rolling, which is beneficial for the uniform deformation of the steel structure during the rolling process, thereby facilitating the acquisition of a uniform microstructure.

[0024] Furthermore, in S4, the starting rolling temperature is 980°C to 1140°C, and the final rolling temperature is 850°C to 1000°C.

[0025] Furthermore, in S4, the cooling rate of the slow cooling is ≤80°C.

[0026] Furthermore, in S4, the annealing temperature is 760° C. to 850° C., and the annealing holding time is 12 h to 20 h.

[0027] Furthermore, in S5, the holding time at 980°C to 1000°C is 1h to 3h, the holding time at 940°C to 960°C is 1h to 3h, and the holding time at 740°C to 760°C is 4h to 12h.

[0028] During the heat treatment process, the normalizing temperature is controlled to avoid the generation of δ-ferrite, so that α-ferrite is transformed into pearlite, thereby eliminating α-ferrite. At the same time, through normalizing, the structure is more uniform and the grains are finer, which is beneficial to the improvement of the toughness and processing performance of the steel. After normalizing, the pearlite is transformed into martensite through quenching, and finally the structure and properties of the martensite are adjusted through tempering to obtain a structure dominated by tempered martensite. No new ferrite is generated during the above heat treatment process, so that the material has better toughness and stability.

[0029] It should be noted that the straightening process needs to be carried out within 12 hours after the heat treatment is completed.

[0030] Furthermore, the chemical composition of 1Cr13 rods for nuclear power is: C 0.12%-0.14%, Si≤0.50%, Mn≤0.55%, S≤0.001%, P≤0.025%, Cr 12.20%-12.40%, Ni0.40%-0.50%, Co≤0.02%, N 0.02%-0.04%, and the balance is Fe and unavoidable impurities.

[0031] The present invention also provides a 1Cr13 bar for nuclear power, characterized in that it is prepared by any of the above-mentioned methods for manufacturing the 1Cr13 bar for nuclear power.

[0032] The manufacturing method of 1Cr13 rod for nuclear power provided by the present invention is beneficial to reducing the formation of ferrite by controlling the contents of C, N and Ni elements, laying a good foundation for subsequent heat treatment, and fully transforming ferrite into tempered martensite by controlling the heat treatment process. The content of ferrite in the organization is ≤1%, which effectively improves the strength and toughness of the material, provides solid and reliable material support for the efficient and safe operation of nuclear power plants, and is particularly suitable for manufacturing driving rods, valve seats, fasteners and other parts of driving mechanisms for nuclear power, and has high practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The metallographic structure diagrams of the 1Cr13 rod for nuclear power prepared in Example 1 at different magnifications, where (a) is 200x, (b) is 500x;

[0034] Figure 2 The metallographic structure diagrams of the 1Cr13 rod for nuclear power prepared in Comparative Example 1 at different magnifications, where (a) is 100x, (b) is 500x;

[0035] Figure 3 The metallographic structure diagrams of the 1Cr13 rods for nuclear power prepared in Comparative Example 2 at different magnifications, where (a) is 100x and (b) is 500x. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0037] In order to better illustrate the present invention, further examples are given below.

[0038] Example 1

[0039] The embodiment of the present invention provides a 1Cr13 bar for nuclear power, the chemical composition of which is:

[0040] C 0.126%, Si 0.46%, Mn 0.52%, P 0.021%, S 0.001%, Cr 12.33%, Ni 0.43%, Co 0.02%, N 0.020%, and the balance is Fe and inevitable impurities.

[0041] The preparation steps of the above-mentioned 1Cr13 rod for nuclear power are as follows:

[0042] S1, the raw materials are subjected to arc furnace smelting, AOD refining and LF refining, and the C and N contents are controlled according to the target values ​​to obtain molten steel that meets the composition requirements; then the molten steel is vacuum degassed by VD, nitrogen is filled in, the N content in the molten steel is controlled according to the target value, and casting is performed to obtain of steel ingots;

[0043] S2, in a protective atmosphere, electroslag remelting the steel ingot, cooling it, and obtaining Electroslag ingots;

[0044] S3, the electroslag ingot is heated to 1140°C in a furnace, kept warm for 4 hours, and then a 2500T fast forging machine is used to pull the blank through a primary forging process. The billet is then charged into a furnace for annealing at a temperature of 850°C and a holding time of 15 hours to obtain a forged steel billet;

[0045] S4, after polishing the surface of the forged steel billet, the forged steel billet is charged into a furnace and heated to 1150°C for 1.5 hours, and then hot rolled to The final rolling temperature is 880°C, and after rolling, the steel is placed in a slow cooling box and slowly cooled to room temperature at a rate of ≤80°C / h, and then annealed at 840°C for 12h to obtain a rolled steel billet;

[0046] S5, firstly heat the rolled steel billet to 990°C for 1 hour, and air cool to room temperature; then heat to 950°C for 1 hour, and oil cool to below 80°C; finally heat to 750°C for 4 hours, and air cool to room temperature, and straighten within 12 hours after the heat treatment is completed to obtain 1Cr13 bars for nuclear power.

[0047] The metallographic structure of the prepared 1Cr13 rod for nuclear power is shown in Figure 1 As shown, its metallographic structure is mainly tempered martensite, and the ferrite content is 0.5%.

[0048] Example 2

[0049] The embodiment of the present invention provides a 1Cr13 bar for nuclear power, the chemical composition of which is:

[0050] C 0.127%, Si 0.45%, Mn 0.52%, P 0.021%, S 0.001%, Cr 12.24%, Ni 0.45%, Co 0.02%, N 0.021%, and the balance is Fe and inevitable impurities.

[0051] The preparation steps of the above-mentioned 1Cr13 rod for nuclear power are as follows:

[0052] S1, the raw materials are subjected to arc furnace smelting, AOD refining and LF refining, and the C and N contents are controlled according to the target values ​​to obtain molten steel that meets the composition requirements; then the molten steel is vacuum degassed by VD, nitrogen is filled in, the N content in the molten steel is controlled according to the target value, and casting is performed to obtain of steel ingots;

[0053] S2, in a protective atmosphere, electroslag remelting the steel ingot, cooling it, and obtaining Electroslag ingots;

[0054] S3, the electroslag ingot is charged into a furnace and heated to 1130°C, kept at this temperature for 5 hours, and then a 2500T fast forging machine is used to pull the blank through a primary forging process until The billet is then charged into a furnace for annealing at 820°C for 24 hours to obtain a forged steel billet.

[0055] S4, after polishing the surface of the forged steel billet, the billet is heated to 1140°C and kept at this temperature for 1.5 hours, and then hot rolled to The final rolling temperature is 850°C, and after rolling, the steel is placed in a slow cooling box and slowly cooled to room temperature at a rate of ≤80°C / h, and then annealed at 760°C for 20h to obtain a rolled steel billet.

[0056] S5, firstly heat the rolled steel billet to 980°C and keep it for 3 hours, and then air cool it to room temperature; then heat it to 940°C and keep it for 3 hours, and then oil cool it to below 80°C; finally heat it to 740°C and keep it for 12 hours, and then air cool it to room temperature. Straighten it within 12 hours after the heat treatment is completed to obtain 1Cr13 bars for nuclear power.

[0057] Example 3

[0058] The embodiment of the present invention provides a 1Cr13 bar for nuclear power, the chemical composition of which is:

[0059] C 0.122%, Si 0.46%, Mn 0.50%, P 0.022%, S 0.001%, Cr 12.34%, Ni 0.44%, Co 0.02%, N 0.022%, and the balance is Fe and inevitable impurities.

[0060] The preparation steps of the above-mentioned 1Cr13 rod for nuclear power are as follows:

[0061] S1, the raw materials are subjected to arc furnace smelting, AOD refining and LF refining, and the C and N contents are controlled according to the target values ​​to obtain molten steel that meets the composition requirements; then the molten steel is vacuum degassed by VD, nitrogen is filled in, the N content in the molten steel is controlled according to the target value, and casting is performed to obtain of steel ingots;

[0062] S2, in a protective atmosphere, electroslag remelting the steel ingot, cooling it, and obtaining Electroslag ingots;

[0063] S3, the electroslag ingot is charged into a furnace and heated to 1150°C, kept at this temperature for 3 hours, and then a 2500T fast forging machine is used to pull the blank through a primary forging process until The billet is then charged into a furnace for annealing at 870°C for 12 hours to obtain a forged steel billet.

[0064] S4, after the surface of the forged steel billet is polished, the furnace is heated to 1160°C and kept at this temperature for 1 hour, and then hot-rolled to The final rolling temperature is 950°C, and after rolling, the steel is placed in a slow cooling box and slowly cooled to room temperature at a rate of ≤80°C / h, and then annealed at a temperature of 850°C and a holding time of 13h to obtain a rolled steel billet;

[0065] S5, firstly heat the rolled steel billet to 1000°C and keep it for 1 hour, then air cool it to room temperature; then heat it to 960°C and keep it for 1 hour, then oil cool it to below 80°C; finally heat it to 760°C and keep it for 4 hours, then air cool it to room temperature, and straighten it within 12 hours after the heat treatment is completed to obtain 1Cr13 bars for nuclear power.

[0066] The metallographic structure of the prepared 1Cr13 rod for nuclear power is mainly tempered martensite, and the ferrite content is less than 1%.

[0067] Embodiment 4 to Embodiment 8

[0068] The composition of the 1Cr13 rods for nuclear power provided in Examples 4 to 8 is shown in Table 1.

[0069] Table 1

[0070]

[0071] The 1Cr13 rod for nuclear power was prepared in exactly the same manner as in Example 1.

[0072] The 1Cr13 bars prepared in Examples 1 to 8 were directly cut into sections, and the composition, high temperature tensile strength, low temperature impact strength and ferrite content were tested according to the methods in GB / T 223, GB / T228.2-2015, GB / T 229-2020 and AMS2315, respectively. The results are shown in Table 2.

[0073] Table 2

[0074]

[0075]

[0076] Comparative Example 1

[0077] This comparative example provides a 1Cr13 bar for nuclear power, the chemical composition of which is:

[0078] C 0.128%, Si 0.35%, Mn 0.48%, P 0.020%, S 0.001%, Cr 12.21%, Ni 0.42%, Co 0.02%, N 0.020%, and the balance is Fe and inevitable impurities.

[0079] The preparation steps of the above-mentioned 1Cr13 rod for nuclear power are as follows:

[0080] S1, the raw materials are subjected to arc furnace smelting, AOD refining and LF refining, and the C and N contents are controlled according to the target values ​​to obtain molten steel that meets the composition requirements; then the molten steel is vacuum degassed by VD, nitrogen is filled in, the N content in the molten steel is controlled according to the target value, and casting is performed to obtain of steel ingots;

[0081] S2, in a protective atmosphere, electroslag remelting the steel ingot, cooling it, and obtaining Electroslag ingots;

[0082] S3, the electroslag ingot is charged into a furnace and heated to 1140°C, kept at this temperature for 4 hours, and then a 2500T fast forging machine is used to pull the blank through a primary forging process until The billet is then charged into a furnace for annealing at a temperature of 850°C and a holding time of 15 hours to obtain a forged steel billet;

[0083] S4, after polishing the surface of the forged steel billet, the billet is heated to 1150°C and kept at this temperature for 1.5 hours, and then hot rolled to The final rolling temperature is 880°C, and after rolling, the steel billet is air-cooled to room temperature to obtain a rolled steel billet;

[0084] S5, treating the rolled steel billet according to the heat treatment system in GB / T 1220-2007: quenching at 980°C for 1 hour, oil cooling to below 80°C, tempering at 720°C for 4 hours, air cooling to room temperature, straightening within 12 hours after the heat treatment is completed, and obtaining 1Cr13 bars for nuclear power.

[0085] The metallographic structure of the 1Cr13 bar prepared in this comparative example is as follows Figure 2 shown.

[0086] The composition, high temperature tensile strength, low temperature impact and ferrite content were tested using the same method as in the example. The results are shown in Table 3.

[0087] Table 3

[0088]

[0089] Comparative Example 2

[0090] This comparative example provides a 1Cr13 bar for nuclear power, the chemical composition of which is:

[0091] C 0.115%, Si 0.35%, Mn 0.48%, P 0.020%, S 0.001%, Cr 12.51%, Ni 0.07%, Co 0.02%, N 0.010%, and the balance is Fe and inevitable impurities.

[0092] The preparation steps of the above-mentioned 1Cr13 rod for nuclear power are as follows:

[0093] S1, the raw materials are subjected to arc furnace smelting, AOD refining and LF refining, and the C and N contents are controlled according to the target values ​​to obtain molten steel that meets the composition requirements; then the molten steel is subjected to VD vacuum degassing and poured to obtain of steel ingots;

[0094] S2, in a protective atmosphere, electroslag remelting the steel ingot, cooling it, and obtaining Electroslag ingots;

[0095] S3, the electroslag ingot is charged into a furnace and heated to 1140°C, kept at this temperature for 4 hours, and then a 2500T fast forging machine is used to pull the blank through a primary forging process until The billet is then charged into a furnace for annealing at a temperature of 850°C and a holding time of 15 hours to obtain a forged steel billet;

[0096] S4, after polishing the surface of the forged steel billet, the billet is heated to 1150°C and kept at this temperature for 1.5 hours, and then hot rolled to The final rolling temperature is 880°C, and after rolling, the steel is placed in a slow cooling box and slowly cooled to room temperature at a rate of ≤80°C / h, and then annealed at 840°C for 12h to obtain a rolled steel billet;

[0097] S5, firstly heat the rolled steel billet to 990°C for 1 hour, and air cool to room temperature; then heat to 950°C for 1 hour, and oil cool to below 80°C; finally heat to 750°C for 4 hours, and air cool to room temperature, and straighten within 12 hours after the heat treatment is completed to obtain 1Cr13 bars for nuclear power.

[0098] The metallographic structure of the 1Cr13 bar prepared in this comparative example is as follows Figure 3 shown.

[0099] The composition, high temperature tensile strength, low temperature impact and ferrite content were tested using the same method as in the example. The results are shown in Table 4.

[0100] Table 4

[0101]

[0102] In summary, the process of the present invention can reduce the ferrite content in the steel to less than 1% by strictly controlling the C, N, and Ni contents and optimizing the heat treatment process, and the high-temperature tensile properties and low-temperature toughness are significantly improved, providing a solid and reliable material support for the efficient and safe operation of nuclear power plants. It is suitable for drive rods, valve seats, fasteners and other components of nuclear power drive mechanisms, is conducive to promoting the steady development of the nuclear power industry, and has a high value of promotion and application.

[0103] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for manufacturing 1Cr13 bars for nuclear power, characterized in that: The steps include: S1, the raw materials are subjected to arc furnace smelting, AOD refining and LF refining to obtain molten steel with a C content of 0.12% to 0.14% and a Ni content of 0.4% to 0.5%; the molten steel is then subjected to VD vacuum degassing, nitrogen is introduced to control the N content in the molten steel to be 0.02% to 0.04%, and casting is performed to obtain a steel ingot; S2, electroslag remelting the steel ingot under a protective atmosphere, cooling the steel ingot to obtain an electroslag ingot; S3, heating and forging the electroslag ingot, and then annealing it to obtain a forged steel billet; S4, grinding the forged steel billet, heating and rolling it, slowly cooling it to room temperature, and annealing it to obtain a rolled steel billet; S5, the rolled steel billet is first heated to 980°C-1000°C and kept warm, then air-cooled to room temperature; then heated to 940°C-960°C and kept warm, then oil-cooled to below 80°C; finally heated to 740°C-760°C and kept warm, then air-cooled to room temperature, and straightened to obtain a method for manufacturing 1Cr13 bars for nuclear power.

2. The method for manufacturing 1Cr13 rods for nuclear power according to claim 1, characterized in that: In S2, the cooling is performed by hood cooling, and the hood cooling time is 24h to 48h.

3. The method for manufacturing 1Cr13 rods for nuclear power according to claim 1, characterized in that: In S3, the heating temperature is 1130° C. to 1150° C., and the insulation time is 3 h to 5 h; and / or In S3, the forging ratio of the forging is 10-11.

4. The method for manufacturing 1Cr13 rods for nuclear power according to claim 1, characterized in that: In S3, the annealing temperature is 820° C. to 870° C., and the annealing holding time is 12 h to 24 h.

5. The method for manufacturing 1Cr13 rods for nuclear power according to claim 1, characterized in that: In S4, the heating temperature is 1130° C. to 1150° C., and the holding time is 1 h to 1.5 h; and / or In S4, the starting rolling temperature is 980°C to 1140°C, and the final rolling temperature is 850°C to 1000°C.

6. The method for manufacturing 1Cr13 rods for nuclear power according to claim 1, characterized in that: In S4, the cooling rate of the slow cooling is ≤80°C.

7. The method for manufacturing 1Cr13 rods for nuclear power according to claim 1, characterized in that: In S4, the annealing temperature is 760° C. to 850° C., and the annealing holding time is 12 h to 20 h.

8. The method for manufacturing 1Cr13 rods for nuclear power according to claim 1, characterized in that: In S5, the holding time at 980°C to 1000°C is 1h to 3h, the holding time at 940°C to 960°C is 1h to 3h, and the holding time at 740°C to 760°C is 4h to 12h.

9. The method for manufacturing 1Cr13 rods for nuclear power according to claim 1, characterized in that: The chemical composition of 1Cr13 bars for nuclear power is: C 0.12%~0.14%, Si≤0.50%, Mn≤0.55%, S≤0.001%, P≤0.025%, Cr12.20%~12.40%, Ni 0.40%~0.50%, Co≤0.02%, N0.02%~0.04%, and the balance is Fe and unavoidable impurities.

10. A 1Cr13 bar for nuclear power, characterized in that: The 1Cr13 rod for nuclear power is prepared by the manufacturing method of any one of claims 1 to 9.

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