CN106086692B - Reactor spentnuclear fuel storing special steel base alloy material and preparation method thereof - Google Patents

Abstract

The invention discloses a special steel-based alloy material for reactor spent fuel storage and a preparation method thereof. The special steel-based alloy material has the following composition and mass percentage: C≤0.03%, N≤0.02%, S≤0.01%, P ≤0.03%, Mn≤1.0%, Cr: 10.0～32.0%, Al: 3.0～20.0%, B:0.5‑5.0%, Ti:0.75‑12.5%, the rest is iron and unavoidable impurities, and Ti content The ratio to the B content satisfies Ti:B=1.5‑2.5. After batching and in-situ formation of micro-nano-sized TiB2 particles in the process of vacuum induction melting, it is cast and molded, and then hot forged, hot rolled and annealed, and finally a special steel-based alloy material for reactor spent fuel storage is produced. rod or plate. The special steel-based alloy material of the invention has the advantages of high strength, low cost, excellent corrosion resistance and processing formability, and the like.

Description

Special steel-based alloy material for reactor spent fuel storage and its preparation method

technical field

The invention relates to a stainless steel alloy material and a preparation method thereof, in particular to an aluminum-containing ferritic stainless steel alloy material and a preparation method thereof, which are applied in the technical field of nuclear functional steel alloy materials.

Background technique

As an efficient and clean energy, nuclear energy not only has obvious advantages in safety, stability and environmental protection, but also is an economical energy, which will surely become a new generation of energy pillar in the future energy organization. While using nuclear energy, it is also accompanied by the generation of spent fuel. The spent fuel discharged from nuclear reactors has extremely strong α, β, and γ radioactivity, accompanied by a certain neutron emission rate, and accompanied by the release of heat. After the spent fuel is unloaded from the reactor, it needs to be stored in the spent fuel pool for a period of time, so that most of the radionuclides with short half-lives decay away and take away their decay heat. Usually, each million-kilowatt-class nuclear power unit can unload 25 tons of spent fuel per year. At present, the accumulated spent fuel in my country has reached more than 1,000 tons; according to the current scale and speed of nuclear power development in my country, by 2020, my country will accumulatively produce 7,500 tons of spent fuel. tons-10,000 tons, and will reach 20,000 tons-25,000 tons in 2030. At present, boron steel is widely used as reactor spent fuel storage. In recent years, it has been able to continuously cast stainless steel with a mass fraction of 0.6% B and 1.0% B. It has high strength, excellent corrosion resistance, and good ability to absorb neutrons. However, the solubility of boron in stainless steel is low, and excessive boron addition will precipitate boride (Fe, Cr)2B, resulting in greatly reduced hot ductility, and it is very difficult to prepare boron steel with higher boron content. B4C/Al neutron absorbing materials have problems such as complex process, serious interface reaction between B4C and Al, corrosion resistance, radiation resistance, and aging during use.

Contents of the invention

In order to solve the problems of the prior art, the object of the present invention is to overcome the deficiencies of the prior art, provide a special steel-based alloy material for reactor spent fuel storage and its preparation method, and greatly reduce the cost of raw materials. The special steel-based alloy of the present invention The material can be used as storage and transportation of reactor spent fuel, and the material is easy to process.

In order to achieve the above-mentioned invention creation purpose, the present invention adopts following inventive concepts:

According to the alloying principle of titanium and boron, the present invention has found through a large number of experimental studies that in the process of vacuum induction melting of high-alumina ferritic stainless steel, micro-nano TiB2 particles dispersed and evenly distributed can be synthesized in situ by adding appropriate proportions of titanium and boron, and The micro-nano TiB2 particles are dispersed and evenly distributed in the special steel-based alloy material, thereby preparing the special steel-based alloy material with high boron content.

According to above-mentioned inventive concept, the present invention adopts following technical scheme:

A special steel-based alloy material for reactor spent fuel storage, the main components of which are composed of the following mass percentages (%): C≤0.03%, N≤0.02%, S≤0.01%, P≤0.03%, Mn≤1.0%, Cr: 10.0-32.0%, Al: 3.0-20.0%, B: 0.5-5.0%, Ti: 0.75-12.5%, the rest is mainly iron and unavoidable impurities, with the increase of B content, Ti content increases, and The mass ratio of Ti content to B content satisfies Ti:B=(1.5˜2.5):1.

As a preferred technical solution of the present invention, the composition of the special steel-based alloy material also contains at least one element of Si and Mo, and the content is Si≤3.0% and Mo≤3.0% in terms of mass percentage (%) of the composition.

As a further preferred technical solution of the above technical solution, the main components of the special steel-based alloy material are composed according to the following mass percentages (%): C: 0.016-0.02%, N: 0.002-0.004%, S: 0.001-0.003%, P: 0.015-0.02%, Mn≤1.0%, Cr: 18.5-25.6%, Al: 5.0-13.0%, B: 0.5-5.0%, Ti: 0.75-12.5%, Si: 0.5-0.8%, and the rest is iron. As a further preferred technical solution, the main components of special steel-based alloy materials are composed according to the following mass percentages (%): C: 0.016-0.02%, N: 0.002-0.004%, S: 0.001-0.003%, P: 0.015-0.02 %, Cr: 18.5-25.6%, Al: 5.0-13.0%, B: 2.5%, Ti: 5.5%, Si: 0.5-0.8%, and the rest is iron.

As another further preferred technical solution of the above technical solution, the main components of the special steel-based alloy material are composed according to the following mass percentage (%): C: 0.015-0.03%, N: 0.005-0.02%, S: 0.001-0.01% , P: 0.01-0.02%, Cr: 20.5-22.3%, Al: 6.0-10.3%, B: 2.0-4.5%, Ti: 4.2-10.0%, Mo: 0.7-1.5%, and the rest is iron.

A method for preparing a special steel-based alloy material for reactor spent fuel storage, comprising the following steps:

a. Vacuum induction smelting process is adopted. When batching raw materials, the main raw material components are formulated according to the following mass percentage (%): C ≤ 0.03%, N ≤ 0.02%, S ≤ 0.01%, P ≤ 0.03%, Mn ≤ 1.0%, Cr: 10.0-32.0%, Al: 3.0-20.0%, B: 0.5-5.0%, Ti: 0.75-12.5%, and the rest of the raw material is iron. With the increase of the amount of B in the raw material, the amount of Ti added increases , and the mass ratio of the amount of Ti added to the added amount of B satisfies Ti:B=(1.5～2.5):1, and all the raw materials weighed after batching are subjected to vacuum induction melting to obtain an alloy melt; Containing at least one element of Si and Mo, based on the mass percentage (%) of the raw material components, the content is Si≤3.0%, Mo≤3.0%; the main components of the raw material are preferably composed according to the following mass percentage (%): C: 0.016～0.02%, N: 0.002～0.004%, S: 0.001～0.003%, P: 0.015～0.02%, Mn≤1.0%, Cr: 18.5～25.6%, Al: 5.0～13.0%, B: 0.5-5.0 %, Ti: 0.75-12.5%, Si: 0.5-0.8%, and the remaining raw material components are iron; the main components of raw materials are further preferably composed according to the following mass percentage (%): C: 0.016-0.02%, N: 0.002-0.004%, S: 0.001-0.003%, P: 0.015-0.02%, Cr: 18.5-25.6%, Al: 5.0-13.0%, B: 2.5%, Ti: 5.5%, Si: 0.5-0.8%, and the rest of the raw material is iron The main components of the raw materials are preferably composed of the following mass percentages (%): C: 0.015-0.03%, N: 0.005-0.02%, S: 0.001-0.01%, P: 0.01-0.02%, Cr: 20.5-22.3%, Al: 6.0-10.3%, B: 2.0-4.5%, Ti: 4.2-10.0%, Mo: 0.7-1.5%, and the remaining raw materials are iron;

b. casting the alloy melt prepared in the above step a, and subjecting the cast alloy ingot to hot forging, hot rolling and annealing heat treatment in sequence, finally making a special steel-based alloy material rod for reactor spent fuel storage lumber or plank.

Compared with the prior art, the present invention has the following obvious outstanding substantive features and significant advantages:

1. Compared with traditional boron steel or B4C/Al-based composite materials, the vacuum induction melting process is adopted. After comprehensive batching and in-situ formation of micro-nano TiB2 particles during the melting process, it is cast and formed, and then hot forged, hot Rolling and annealing processes, etc., finally produce a special steel-based alloy material bar or plate for reactor spent fuel storage. The special steel-based alloy material for reactor spent fuel storage in the present invention has high strength, low cost, corrosion resistance and processing Excellent formability and other characteristics;

2. After hot-rolling and annealing the special steel-based alloy materials used in the storage of reactor spent fuel in the present invention, the tensile fracture strength at room temperature is in the range of 600-1000Mpa, which effectively inhibits the aging process during use. Defects are the best candidate materials to replace traditional boron steel or B4C/Al-based composite materials in the future, which can greatly reduce the cost of raw materials.

detailed description

Preferred embodiments of the present invention are described in detail as follows:

Embodiment one:

In this embodiment, a method for preparing a special steel-based alloy material for reactor spent fuel storage includes the following steps:

a. The vacuum induction smelting process is adopted, and when the raw materials are batched, the raw material ingredients used are composed according to the following mass percentage (%) for raw material batching:

Vacuum induction melting is carried out on all raw materials weighed after batching to obtain alloy melt;

b. casting the alloy melt prepared in the above step a, and subjecting the cast alloy ingot to hot forging, hot rolling and annealing heat treatment in sequence, finally making a special steel-based alloy material rod for reactor spent fuel storage material.

This example adopts the vacuum induction melting process. After the in-situ formation of micro-nano TiB2 particles in the melting process of comprehensive ingredients, it is cast and formed, and then hot forged, hot rolled and annealed. Finally, a reactor spent fuel is produced. Special steel-based alloy bars are used for storage. After experimental testing, the test results show that the tensile fracture strength at room temperature of the special steel-based alloy material bar prepared in this embodiment is greater than 750 MPa. The mechanical and corrosion resistance properties of the special steel-based alloy material prepared in this example are superior to traditional boron steel or B4C/Al-based composite materials, and can be used as parts such as tubes and plates for reactor spent fuel storage and utilization. The best candidate materials to replace traditional boron steel or B4C/Al-based composite materials in the future can greatly reduce the cost of raw materials.

Embodiment two:

This embodiment is basically the same as Embodiment 1, especially in that:

In this embodiment, a method for preparing a special steel-based alloy material for reactor spent fuel storage includes the following steps:

a. The vacuum induction smelting process is adopted, and when the raw materials are batched, the raw material ingredients used are composed according to the following mass percentage (%) for raw material batching:

Vacuum induction melting is carried out on all raw materials weighed after batching to obtain alloy melt;

b. This step is the same as in Embodiment 1.

After experimental testing, the test results show that the tensile fracture strength at room temperature of the special steel-based alloy material bar prepared in this embodiment is greater than 900 MPa. The mechanical and corrosion resistance properties of the special steel-based alloy material prepared in this example are superior to traditional boron steel or B4C/Al-based composite materials, and can be used as parts such as tubes and plates for reactor spent fuel storage and utilization. The best candidate materials to replace traditional boron steel or B4C/Al-based composite materials in the future can greatly reduce the cost of raw materials.

Embodiment three:

This embodiment is basically the same as the previous embodiment, and the special features are:

In this embodiment, a method for preparing a special steel-based alloy material for reactor spent fuel storage includes the following steps:

a. The vacuum induction smelting process is adopted, and when the raw materials are batched, the raw material ingredients used are composed according to the following mass percentage (%) for raw material batching:

Vacuum induction melting is carried out on all raw materials weighed after batching to obtain alloy melt;

b. This step is the same as in Embodiment 1.

Experimental testing shows that the tensile fracture strength at room temperature of the special steel-based alloy material bar prepared in this embodiment is greater than 850 MPa. The mechanical and corrosion resistance properties of the special steel-based alloy material prepared in this example are superior to traditional boron steel or B4C/Al-based composite materials, and can be used as parts such as tubes and plates for reactor spent fuel storage and utilization. The best candidate materials to replace traditional boron steel or B4C/Al-based composite materials in the future can greatly reduce the cost of raw materials.

Embodiment four:

This embodiment is basically the same as the previous embodiment, and the special features are:

In this embodiment, a method for preparing a special steel-based alloy material for reactor spent fuel storage includes the following steps:

a. The vacuum induction smelting process is adopted, and when the raw materials are batched, the raw material ingredients used are composed according to the following mass percentage (%) for raw material batching:

Vacuum induction melting is carried out on all raw materials weighed after batching to obtain alloy melt;

b. This step is the same as in Embodiment 1.

Experimental testing shows that the tensile fracture strength at room temperature of the special steel-based alloy material bar prepared in this embodiment is greater than 860 MPa. The mechanical and corrosion resistance properties of the special steel-based alloy material prepared in this example are superior to traditional boron steel or B4C/Al-based composite materials, and can be used as parts such as tubes and plates for reactor spent fuel storage and utilization. The best candidate materials to replace traditional boron steel or B4C/Al-based composite materials in the future can greatly reduce the cost of raw materials.

The embodiments of the present invention have been described above, but the present invention is not limited to the above-mentioned embodiments, and various changes can also be made according to the purpose of the invention of the present invention. All changes made under the spirit and principles of the technical solutions of the present invention, Modification, substitution, combination or simplification shall all be equivalent replacement methods, as long as it meets the purpose of the invention and does not deviate from the technical principle and inventive concept of the special steel-based alloy material for reactor spent fuel storage and its preparation method of the present invention , all belong to the protection scope of the present invention.

Claims (10)

1. A special steel-based alloy material for reactor spent fuel storage, characterized in that its main components are composed of the following mass percentages (%): C≤0.03%, N≤0.02%, S≤0.01%, P≤0.03% , Mn≤1.0%, Cr: 10.0-32.0%, Al: 3.0-20.0%, B: 0.5-5.0%, Ti: 0.75-12.5%, the rest is mainly iron and unavoidable impurities, with the increase of B content , Ti content increases, and the mass ratio of Ti content to B content satisfies Ti:B=(1.5～2.5):1. 2. The special steel-based alloy material for reactor spent fuel storage according to claim 1, characterized in that: its composition also contains at least one element among Si and Mo, and the content is Si ≤3.0%, Mo≤3.0%. 3. The special steel-based alloy material for reactor spent fuel storage according to claim 2, characterized in that: the main components are composed according to the following mass percentages (%): C: 0.016-0.02%, N: 0.002-0.004%, S: 0.001～0.003%, P: 0.015～0.02%, Mn≤1.0%, Cr: 18.5～25.6%, Al: 5.0～13.0%, B: 0.5-5.0%, Ti: 0.75-12.5%, Si: 0.5～0.8 %, and the rest is iron. 4. The special steel-based alloy material for reactor spent fuel storage according to claim 3, characterized in that: the main components are composed according to the following mass percentages (%): C: 0.016-0.02%, N: 0.002-0.004%, S: 0.001-0.003%, P: 0.015-0.02%, Cr: 18.5-25.6%, Al: 5.0-13.0%, B: 2.5%, Ti: 5.5%, Si: 0.5-0.8%, and the rest is iron. 5. The special steel-based alloy material for reactor spent fuel storage according to claim 2, wherein the main components are composed according to the following mass percentages (%): C: 0.015-0.03%, N: 0.005-0.02%, S: 0.001～0.01%, P: 0.01～0.02%, Cr: 20.5～22.3%, Al: 6.0～10.3%, B: 2.0-4.5%, Ti: 4.2-10.0%, Mo: 0.7～1.5%, and the rest is iron. 6. A method for preparing a special steel-based alloy material for reactor spent fuel storage, characterized in that it comprises the following steps: a. Vacuum induction smelting process is adopted. When batching raw materials, the main raw material components are formulated according to the following mass percentage (%): C≤0.03%, N≤0.02%, S≤0.01%, P≤0.03%, Mn≤ 1.0%, Cr: 10.0-32.0%, Al: 3.0-20.0%, B: 0.5-5.0%, Ti: 0.75-12.5%, and the remaining raw materials are mainly iron. With the increase of the amount of B added in the raw materials, the amount of Ti added increase, and the mass ratio of Ti addition to B addition satisfies Ti:B=(1.5～2.5):1, all raw materials weighed after batching are subjected to vacuum induction melting to obtain alloy melt; b. Casting the alloy melt prepared in step a, and then subjecting the cast alloy ingot to hot forging, hot rolling, and annealing heat treatment in sequence, to finally obtain a special steel-based alloy material bar for reactor spent fuel storage or plates. 7. The method for preparing special steel-based alloy materials for reactor spent fuel storage according to claim 6, characterized in that: in the step a, at least one element of Si and Mo is also added to the raw material composition, so as to In terms of mass percentage (%) of raw material components, the content is Si≤3.0%, Mo≤3.0%. 8. The method for preparing special steel-based alloy materials for reactor spent fuel storage according to claim 7, characterized in that: in the step a, the main components of the raw materials are composed according to the following mass percentage (%): C: 0.016-0.02 %, N: 0.002～0.004%, S: 0.001～0.003%, P: 0.015～0.02%, Mn≤1.0%, Cr: 18.5～25.6%, Al: 5.0～13.0%, B: 0.5-5.0%, Ti : 0.75-12.5%, Si: 0.5-0.8%, and the rest of the raw materials are iron. 9. The method for preparing special steel-based alloy materials for reactor spent fuel storage according to claim 8, characterized in that: in the step a, the main components of the raw materials are composed according to the following mass percentage (%): C: 0.016-0.02 %, N: 0.002-0.004%, S: 0.001-0.003%, P: 0.015-0.02%, Cr: 18.5-25.6%, Al: 5.0-13.0%, B: 2.5%, Ti: 5.5%, Si: 0.5 ~0.8%, the rest of the raw material is iron. 10. The method for preparing special steel-based alloy materials for reactor spent fuel storage according to claim 7, characterized in that: in said step a, the main components of the raw materials are composed according to the following mass percentage (%): C: 0.015-0.03 %, N: 0.005～0.02%, S: 0.001～0.01%, P: 0.01～0.02%, Cr: 20.5～22.3%, Al: 6.0～10.3%, B: 2.0-4.5%, Ti: 4.2-10.0% , Mo: 0.7-1.5%, and the rest of the raw materials are iron.