Heat treatment method for improving mechanical property of shielding material in nuclear fusion
By controlling the precipitation and distribution of boron compounds in the steelmaking, billet heating, rolling, and heat treatment processes of boron-containing stainless steel, the problem of poor mechanical properties of boron-containing stainless steel in nuclear fusion reactors was solved, achieving efficient shielding effect and improved mechanical properties.
Patent Information
- Application Number
- CN202510924078.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-04
- Publication Date
- 2025-10-24
AI Technical Summary
In the existing technology, when studying boron-containing stainless steel with high boron content, the precipitation, aggregation and growth rules of borides are unclear, resulting in poor mechanical properties and shielding effects, especially the risk of cracking in nuclear fusion reactors.
A heat treatment method is adopted, including steelmaking, billet heating, rolling and heat treatment processes. Through solution treatment, aging treatment and step heating, the precipitation and distribution of borides are controlled to ensure that the borides are partially agglomerated and do not form a network, thereby improving mechanical properties.
It improves the shielding effect and mechanical properties of boron-containing stainless steel, ensuring that the absorption rate of neutrons in the shielded area reaches 85% to 95%, while also enhancing the tensile strength and plasticity of the material.
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Figure CN120830009A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of heat treatment, and particularly relates to a heat treatment method for improving mechanical properties of shielding materials in nuclear fusion. BACKGROUND
[0002] In a nuclear fusion reactor, a large number of neutrons are generated, which have high energy and strong penetration and can cause great damage to the structural materials of the reactor. Boron-containing stainless steel (hereinafter referred to as boron-containing stainless steel) can effectively block neutron radiation and reduce the harm to surrounding equipment and personnel because the boron element can efficiently absorb neutrons. Meanwhile, the boron-containing stainless steel has good mechanical properties and corrosion resistance of stainless steel, can maintain structural integrity and stability in the complex high-temperature and strong radiation environment of the nuclear fusion reactor, and can ensure the safe and stable operation of the reactor. Increasing the boron content can improve the shielding ability of neutrons, and uniform distribution can ensure stable shielding effect, but a higher boron content can lead to uneven distribution, and further lead to poor mechanical properties and shielding effect.
[0003] At present, according to the domestic research on boron-containing stainless steel, the research on high-content boron is limited to simple tempering, and the precipitation, aggregation and growth of borides in high-boron steel with a boron content of 2% during tempering are still not very clear. The interaction between borides and carbides under different tempering temperatures and times, and how they jointly affect the mechanical properties such as strength, toughness and hardness of the steel, still need further in-depth research. Therefore, a heat treatment method for improving the mechanical properties of shielding materials in nuclear fusion is needed, which is designed to address the poor mechanical properties caused by large borides in metallurgical products. This process can ensure that the shielding performance of the shielding area of the boron-containing stainless steel after step heat treatment reaches a good effect, i.e., the shielding effect of the shielding material is that the thermal neutron absorption rate is greater than or equal to 85%, the boron content is 1.8-2.1wt%, and the structure presents that the borides are partially aggregated (size 5-15μm) but not connected into a network. At the same time, the mechanical properties of the boron-containing stainless steel are further improved, which has important social and economic significance.
[0004] Therefore, a heat treatment method for improving the mechanical properties of shielding materials in nuclear fusion is needed, which is designed to address the poor mechanical properties caused by large borides in metallurgical products. This process can ensure that the shielding performance of the shielding area of the boron-containing stainless steel after step heat treatment reaches a good effect, i.e., the shielding effect of the shielding material is that the thermal neutron absorption rate is greater than or equal to 85%, the boron content is 1.8-2.1wt%, and the structure presents that the borides are partially aggregated (size 5-15μm) but not connected into a network. At the same time, the mechanical properties of the boron-containing stainless steel are further improved, which has important social and economic significance. SUMMARY
[0005] The technical problem solved by the present application is to provide a heat treatment method for improving the mechanical properties of shielding materials in nuclear fusion, which is used to reduce the cracking caused by the brittle nature of boride in boron-containing stainless steel.
[0006] To solve the above technical problems, the technical scheme adopted by the present application is: a heat treatment method for improving the mechanical properties of shielding materials in nuclear fusion, the heat treatment method comprising a steelmaking process, a billet heating process, a rolling process and a heat treatment process; the heat treatment method comprises the following steps: S1, solid solution treatment: the boron-containing stainless steel is placed in a heating furnace and heated to 1180-1250 DEG C, and after the core of the boron-containing stainless steel is heated, solid solution treatment is carried out, and the boron-containing stainless steel is kept for ≥60h during the solid solution treatment; S2, aging treatment: after the solid solution treatment of the boron-containing stainless steel is completed, the boron-containing stainless steel is cooled to 500-650 DEG C, and the boron-containing stainless steel is kept for ≥4h during the aging treatment; S3, stepwise heating: after the aging treatment of the boron-containing stainless steel is completed, the boron-containing stainless steel is heated to 800-1000 DEG C, and kept for 2-4h, and then heated to 1150-1200 DEG C, and kept for 1-2h.
[0007] S4, air cooling treatment: after the stepwise heating of the boron-containing stainless steel is completed, it is taken out and air cooled to room temperature.
[0008] In the solid solution treatment of the present application, the carrier gas is air, and the boron-containing stainless steel will appear an iron oxide skin with a thickness of ≥20mm.
[0009] After the step S2 and before the step S3 of the heat treatment method of the present application, the boron-containing stainless steel does not need to be taken out of the furnace, the carrier gas is air, and the thickness of the iron oxide skin is ≥20mm.
[0010] After the step S3 and before the step S4 of the heat treatment method of the present application, the boron-containing stainless steel needs to be quickly taken out, and the time is controlled to be 60-120s.
[0011] After the air cooling in the step S4 of the present application, the tensile properties of the boron-containing stainless steel meet the requirements of yield strength Rel≥300MPa, tensile strength Rm≥511MPa and elongation A≥6.6%.
[0012] The chemical composition and mass percentage of the boron-containing stainless steel of the present application are as follows: B: 1.80～2.10 %, Cr: 12.00～20.00 %, Ni: 5.00～20.00 %, Mo: 2.00～6.00 %, C: 0.03～0.10 %, and the balance is Fe and unavoidable impurities.
[0013] The specifications of the boron-containing stainless steel of the present invention are 210-230 mm in length, 980-1000 mm in width and 28-33 mm in thickness.
[0014] The shielding effect of the boron-containing stainless steel after heat treatment of the present invention is a thermal neutron absorption rate of 85% to 95%. 60 The linear attenuation coefficient of Coγ-ray is about 0.38-0.41cm -1 ,against 137 The linear attenuation coefficient of Csγ-ray is about 0.52-0.57cm -1 ; High boron steel with uniform boride distribution is 60 The linear attenuation coefficient of Coγ-rays can reach 0.62cm -1 ,against 137 The linear attenuation coefficient of Csγ-rays is about 0.97 cm -1 , which is more than 50% higher than that of ordinary boron steel, and the γ-ray attenuation coefficient is significantly improved.
[0015] The boron content of the heat-treated boron-containing stainless steel of the present invention is 1.8-2.0 wt %, and the structure shows that the boride is partially agglomerated with a size of 5-15 μm but not connected into a network.
[0016] The beneficial effect of adopting the above technical solution is that: the present invention is designed to address the problem that large borides in metallurgical products cause poor mechanical properties, which in turn leads to cracking in subsequent rolling processes. This process can ensure that the shielding area of boron-containing stainless steel achieves good results after step heat treatment, while further improving the mechanical properties of boron-containing stainless steel. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 This is the SEM image of the boron-containing stainless steel after rolling in Example 1 of the present invention; Figure 2 This is an SEM image of the boron-containing stainless steel after heat treatment in Example 1 of the present invention. DETAILED DESCRIPTION
[0018] In order to make the purpose, technical solutions 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 intended to limit the present invention.
[0019] A heat treatment method for improving the mechanical properties of shielding materials used in nuclear fusion includes a steelmaking process, a steel billet heating process, a rolling process, and a heat treatment process. The control parameters are as follows: 1) Steelmaking process: Adopt measures such as drying alloy materials and vacuum treatment to obtain a B content of 1.8-2.1% in molten steel.
[0020] 2) Billet heating process: the billet is cooled in a stack for 100-120 h at 100-120 °C before being heated in a furnace, the B content in the billet after the stack cooling is 1.8-2.1%, the billet is heated in a regenerative heating furnace, the furnace gas temperature in the preheating section is 950 °C, the furnace gas temperature in the heating section is 1150-1180 °C, the furnace gas temperature in the soaking section is 1200-1220 °C, and the billet is in the furnace for 140-160 min.
[0021] The boron-containing stainless steel is naturally cooled after finish rolling, and if forced cooling is used after rolling, the plasticity of the boron-containing stainless steel is damaged.
[0022] 3) Rolling process: the open rolling temperature is 1100-1180 °C, the reduction per pass is 15-30%, and the boride (mainly Fe2B, Cr2B, etc.) is formed in the air cooling state after rolling.
[0023] 4) Heat treatment process: S1, solid solution treatment: the boron-containing stainless steel is placed in a heating furnace and heated to 1180-1250 °C, and after the core of the boron-containing stainless steel is heated, the solid solution treatment is performed, and the boron-containing stainless steel is kept for ≥60 h during the solid solution treatment; In the solid solution treatment in step S1, the carrier gas is air, and the boron-containing stainless steel will have an iron oxide skin with a thickness of ≥20 mm; S2, aging treatment: after the solid solution treatment of the boron-containing stainless steel is completed, the boron-containing stainless steel is cooled to 500-650 °C, and the boron-containing stainless steel is kept for ≥4 h during the aging treatment; After step S2 and before step S3, the boron-containing stainless steel does not need to be taken out of the furnace, the carrier gas is air, and the thickness of the iron oxide skin is ≥20 mm.
[0024] S3, stepwise heating: after the aging treatment of the boron-containing stainless steel is completed, the boron-containing stainless steel is heated to 800-1000 °C, and kept for 2-4 h. After the boron-containing stainless steel is heated to 1150-1200 °C, it is kept for 1-2 h; After step S3 and before step S4, the boron-containing stainless steel needs to be quickly taken out, and the time is controlled to be 60-120 s; S4, air cooling treatment: after the stepwise heating of the boron-containing stainless steel is completed, it is taken out and air cooled to room temperature.
[0025] After air cooling, the tensile properties of the boron-containing stainless steel meet the yield strength Rel: 300-330 MPa, the tensile strength Rm: 511-525 MPa, and the elongation A: 6.6-8.0%. Example 1
[0026] A heat treatment method for improving mechanical properties of shielding materials in nuclear fusion, comprising a steelmaking process, a billet heating process, a rolling process, and a heat treatment process, and the control parameters are as follows: 1) Steelmaking process: dry alloy materials, vacuum treatment and other measures are adopted to obtain a steel liquid B content of 1.8%.
[0027] 2) Billet heating process: the billet is cooled in a 100℃ environment before being heated in a furnace, and the cooling time is 100h. After cooling, the B content in the billet is 1.8%, and the billet is heated in a regenerative heating furnace. The preheating section furnace gas temperature is 950℃, the heating section furnace gas temperature is 1150℃, and the soaking section furnace gas temperature is 1200℃. The billet is in the furnace for 140min.
[0028] After the boron-containing stainless steel is finished rolling, it is naturally cooled. If forced cooling is used after rolling, the plasticity of the boron-containing stainless steel will be damaged.
[0029] 3) Rolling process: air cooling after rolling is adopted, and borides (mainly Fe2B, Cr2B, etc.) are formed in the air cooling state after rolling.
[0030] 4) Heat treatment process: S1, solid solution treatment: the boron-containing stainless steel is placed in a heating furnace and heated to 1180℃, and after the core of the boron-containing stainless steel reaches the temperature, solid solution treatment is carried out. The boron-containing stainless steel is kept for 60h during the solid solution treatment process; During the solid solution treatment in step S1, the carrier gas is air, and the boron-containing stainless steel will appear an iron oxide skin with a thickness of 20mm.
[0031] S2, aging treatment: after the solid solution treatment of the boron-containing stainless steel is completed, the boron-containing stainless steel is cooled to 500℃, and the boron-containing stainless steel is kept for 4h during the aging treatment. After step S2 and before step S3, the boron-containing stainless steel does not need to be taken out of the furnace, the carrier gas is air, and the thickness of the iron oxide skin is 20mm.
[0032] S3, stepwise heating: after the aging treatment of the boron-containing stainless steel is completed, the boron-containing stainless steel is heated to 800℃, and the holding time is 2h. After the boron-containing stainless steel reaches the temperature, it is continuously heated to 1150℃, and the holding time is 1h.
[0033] Before step S4 after step S3, the boron-containing stainless steel needs to be quickly taken out, and the time control is within 60s.
[0034] S4, air cooling treatment: after the stepwise heating of the boron-containing stainless steel is completed, it is taken out and air cooled to room temperature.
[0035] After heat treatment, the boride of the boron-containing stainless steel is partially aggregated in structure, with a size of 5μm, but it is not connected into a network; the shielding effect is a thermal neutron absorption rate of 85%.
[0036] The microstructure of the boron-containing stainless steel after heat treatment is shown in the attached Figure 1 、 2 The boride is more uniformly dispersed and the particle size is smaller after heat treatment, as shown by the SEM analysis of the morphology of the boron-containing stainless steel after rolling and heat treatment. Figure 1 、 2 The attached figure in Example 1 (the same as the attached figures in the remaining examples, so omitted). Example 2
[0037] A heat treatment method for improving the mechanical properties of a shielding material in nuclear fusion, comprising a steelmaking process, a billet heating process, a rolling process, and a heat treatment process, with the following control parameters: 1) Steelmaking process: dry alloy materials, vacuum treatment, etc. to obtain a steel liquid with a B content of 1.9%.
[0038] 2) Billet heating process: the billet is cooled in a 100℃ environment before entering the furnace for heating, with a cooling time of 100h. After cooling, the B content in the billet is 1.9%. The billet is heated in a regenerative heating furnace, with a preheating section furnace gas temperature of 950℃, a heating section furnace gas temperature of 1150℃, and a soaking section furnace gas temperature of 1200℃. The billet is in the furnace for 140min.
[0039] The boron-containing stainless steel is naturally cooled after finishing rolling. If forced cooling is used after rolling, the plasticity of the boron-containing stainless steel will be damaged.
[0040] 3) Rolling process: air cooling after rolling to form borides (mainly Fe2B, Cr2B, etc.).
[0041] 4) Heat treatment process: S1, solid solution treatment: the boron-containing stainless steel is placed in a heating furnace and heated to 1200℃. After the core of the boron-containing stainless steel reaches the temperature, solid solution treatment is performed. The boron-containing stainless steel is kept at temperature for 65h during the solid solution treatment. During the solid solution treatment in step S1, the carrier gas is air, and the boron-containing stainless steel will have an iron oxide skin with a thickness of 25mm.
[0042] S2, aging treatment: after the solid solution treatment of the boron-containing stainless steel is completed, the boron-containing stainless steel is cooled to 550℃ and kept at temperature for 4.5h for aging treatment. After step S2 and before step S3, the boron-containing stainless steel does not need to be taken out of the furnace. The carrier gas is air, and the iron oxide skin has a thickness of 25mm.
[0043] S3, step temperature: after the aging treatment of boron-containing stainless steel, the boron-containing stainless steel is heated to 900℃, and the holding time is 3h. The boron-containing stainless steel is continuously heated to 1180℃ after the time, and the holding time is 1.5h.
[0044] After step S3 and before step S4, the boron-containing stainless steel needs to be quickly taken out at this time, and the time is controlled within 80s.
[0045] S4, air cooling treatment: after the boron-containing stainless steel is taken out after the step temperature, it is air cooled to room temperature.
[0046] After heat treatment, the boride of the boron-containing stainless steel is partially aggregated in structure, with a size of 10μm, but not connected into a network; the shielding effect is thermal neutron absorption rate of 87%. Example 3
[0047] A heat treatment method for improving the mechanical properties of shielding materials in nuclear fusion includes a steelmaking process, a billet heating process, a rolling process, and a heat treatment process, and the control parameters are as follows: 1) Steelmaking process: dry alloy materials, vacuum treatment and other measures are adopted to obtain a steel liquid B content of 2.0%.
[0048] 2) Billet heating process: the billet is stacked and cooled in a 100℃ environment before entering the furnace for heating, and the stacking and cooling time is 100h. After stacking and cooling, the B content in the billet is 2.1%, and the billet is heated in a regenerative heating furnace. The preheating section furnace gas temperature is 950℃, the heating section furnace gas temperature is 1150℃, and the soaking section furnace gas temperature is 1200℃. The billet is in the furnace for 140min.
[0049] After the boron-containing stainless steel is finished rolling, it is naturally cooled. If forced cooling is used after rolling, the plasticity of the boron-containing stainless steel will be damaged.
[0050] 3) Rolling process: air cooling is used after rolling to form borides (mainly Fe2B, Cr2B, etc.) in the air cooling state after rolling.
[0051] 4) Heat treatment process: S1, solid solution treatment: the boron-containing stainless steel is placed in a heating furnace and heated to 1230℃, and solid solution treatment is carried out after the core of the boron-containing stainless steel is heated. The boron-containing stainless steel is kept for 70h during the solid solution treatment; During the solid solution treatment in step S1, the carrier gas is air, and the boron-containing stainless steel will appear iron oxide scale with a thickness of 28mm.
[0052] S2, aging treatment: after the solid solution treatment of the boron-containing stainless steel is completed, the boron-containing stainless steel is cooled to 630℃, and the boron-containing stainless steel is kept for 5h during the aging treatment. After step S2 and before step S3, the boron-containing stainless steel does not need to be taken out of the furnace, the carrier gas is air, and the thickness of the iron oxide scale is 28 mm.
[0053] S3, step-up heating: after the aging treatment of the boron-containing stainless steel is completed, the boron-containing stainless steel is heated to 950℃, and the holding time is 3.5 h. After the boron-containing stainless steel is heated to 1190℃, the holding time is 1.8 h.
[0054] After step S3 and before step S4, the boron-containing stainless steel needs to be quickly taken out at this time, and the time is controlled within 100 s.
[0055] S4, air cooling treatment: after the step-up heating of the boron-containing stainless steel is completed, it is taken out and air-cooled to room temperature.
[0056] After the heat treatment, the boride of the boron-containing stainless steel is partially aggregated in structure, with a size of 13 μm, but not connected into a network; the shielding effect is a thermal neutron absorption rate of 93%. Example 4
[0057] A heat treatment method for improving the mechanical properties of a shielding material in nuclear fusion includes a steelmaking process, a billet heating process, a rolling process, and a heat treatment process, and the control parameters are as follows: 1) Steelmaking process: dry alloy materials, vacuum treatment and other measures are adopted to obtain a steel liquid B content of 2.1%.
[0058] 2) Billet heating process: the billet is stacked and cooled in a 100℃ environment before being heated in the furnace, and the stacking and cooling time is 100 h. After stacking and cooling, the B content in the billet is 2.2%. The billet is heated in a regenerative heating furnace, the preheating section furnace gas temperature is 950℃, the heating section furnace gas temperature is 1150℃, and the soaking section furnace gas temperature is 1200℃. The billet is in the furnace for 140 min.
[0059] After the boron-containing stainless steel is finished rolling, it is naturally cooled. If forced cooling is used after rolling, the plasticity of the boron-containing stainless steel will be damaged.
[0060] 3) Rolling process: air cooling is used after rolling, and borides (mainly Fe2B, Cr2B, etc.) are formed in the air-cooled state after rolling.
[0061] 4) Heat treatment process: S1, solid solution treatment: the boron-containing stainless steel is placed in a heating furnace and heated to 1250℃, and after the core of the boron-containing stainless steel is heated, solid solution treatment is performed. The boron-containing stainless steel is kept at temperature for 80 h during the solid solution treatment. In the solid solution treatment in step S1, the carrier gas is air, and the boron-containing stainless steel subjected to the solid solution treatment will have an iron oxide scale with a thickness of 30 mm.
[0062] S2, aging treatment: after the solid solution treatment of the boron-containing stainless steel is completed, the boron-containing stainless steel is cooled to 650 DEG C, and the boron-containing stainless steel is aged for 6 hours. After step S2 and before step S3, the boron-containing stainless steel is not taken out of the furnace, the carrier gas is air, and the thickness of the iron oxide skin is 30 mm.
[0063] S3, stepwise heating: after the aging treatment of the boron-containing stainless steel is completed, the boron-containing stainless steel is heated to 1000 DEG C, and the boron-containing stainless steel is aged for 4 hours. After the time, the boron-containing stainless steel is continuously heated to 1200 DEG C, and the boron-containing stainless steel is aged for 2 hours.
[0064] After step S3 and before step S4, the boron-containing stainless steel is taken out quickly at this time, and the time is controlled to be 120 seconds.
[0065] S4, air cooling treatment: after the stepwise heating of the boron-containing stainless steel is completed, the boron-containing stainless steel is taken out and air cooled to room temperature.
[0066] The boride of the boron-containing stainless steel after the heat treatment is partially aggregated in structure, the size is 15 microns, but is not connected into a network; the shielding effect is a thermal neutron absorption rate of 95%.
[0067] The chemical composition of the boron-containing stainless steel obtained in each example and the weight percentage are shown in Table 1. The mechanical properties of the boron-containing stainless steel are detected according to GB / T228.1 "Metallic Materials Tensile Test Part 1: Room Temperature Test Method", and the detection results and specifications are shown in Table 2.
[0068] Table 1 Chemical composition of boron-containing stainless steel of each example (wt%)
[0069] Table 2 Mechanical properties of stainless steel of each example (wt%)
[0070] The above examples are only used to illustrate but not to limit the technical solutions of the present application. Although the present application is described in detail with reference to the above examples, those skilled in the art should understand that the present application can still be modified or equivalently replaced without departing from the spirit and scope of the present application, and any modification or partial replacement should be covered in the scope of the claims of the present application.
Claims
1. A heat treatment method for improving the mechanical properties of a shielding material in nuclear fusion, characterized by: The heat treatment method comprises a steelmaking process, a billet heating process, a rolling process and a heat treatment process; the heat treatment method comprises the following steps: S1, solid solution treatment: the boron-containing stainless steel is placed in a heating furnace for heating to 1180-1250 DEG C, and after the core of the boron-containing stainless steel is heated, solid solution treatment is performed, and the boron-containing stainless steel is kept for greater than or equal to 60 hours during the solid solution treatment; S2, aging treatment: after the solid solution treatment of the boron-containing stainless steel is completed, the boron-containing stainless steel is cooled to 500-650 DEG C, and the boron-containing stainless steel is kept for greater than or equal to 4 hours during the aging treatment; S3, stepwise heating: after the aging treatment of the boron-containing stainless steel is completed, the boron-containing stainless steel is heated to 800-1000 DEG C, and kept for 2-4 hours, and then heated to 1150-1200 DEG C, and kept for 1-2 hours; S4, air cooling treatment: after the stepwise heating of the boron-containing stainless steel is completed, the boron-containing stainless steel is taken out and air cooled to room temperature.
2. The heat treatment method for improving mechanical properties of a shielding material in nuclear fusion according to claim 1, wherein: In the solid solution treatment of the step S1, the carrier gas is air, and the boron-containing stainless steel is oxidized to form an iron oxide scale with a thickness greater than or equal to 20 mm.
3. The heat treatment method for improving mechanical properties of a shielding material in nuclear fusion according to claim 1, wherein: In the heat treatment method, after the step S2 and before the step S3, the boron-containing stainless steel does not need to be taken out of the furnace, the carrier gas is air, and the thickness of the iron oxide scale is greater than or equal to 20 mm.
4. The heat treatment method for improving mechanical properties of a shielding material in nuclear fusion according to claim 1, wherein: In the heat treatment method, after the step S3 and before the step S4, the boron-containing stainless steel needs to be quickly taken out, and the time is controlled to be 60-120 seconds.
5. The heat treatment method for improving mechanical properties of a shielding material in nuclear fusion according to any one of claims 1 to 4, characterized in that: In the step S4, after air cooling, the boron-containing stainless steel has a tensile property that satisfies a yield strength Rel greater than or equal to 300 MPa, a tensile strength Rm greater than or equal to 511 MPa, and an elongation A greater than or equal to 6.6%.
6. The heat treatment method for improving mechanical properties of a shielding material in nuclear fusion according to any one of claims 1 to 4, characterized by: The boron-containing stainless steel has a chemical composition and a mass percentage of B: 1.80-2.10%, Cr: 12.00-20.00%, Ni: 5.00-20.00%, Mo: 2.00-6.00%, C: 0.03-0.10%, and the balance of Fe and inevitable impurities.
7. The method of claim 1-4, wherein the method is characterized by: The boron-containing stainless steel has a specification of a length of 210-230 mm, a width of 980-1000 mm, and a thickness of 28-33 mm.
8. The method of claim 1-4, wherein the method is characterized by: The boron-containing stainless steel after the heat treatment has a shielding effect of a thermal neutron absorption rate of 85-95%.
9. The method of claim 1-4, wherein the method is characterized by: The boron-containing stainless steel after the heat treatment has a boron content of 1.8-2.0 wt%, and the boride structure is partially aggregated with a size of 5-15 microns, but is not connected into a network.