CN112251666A - Austenitic stainless steel forging for spent fuel post-treatment and manufacturing method thereof - Google Patents
Austenitic stainless steel forging for spent fuel post-treatment and manufacturing method thereof Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
- B21J5/00—Methods for forging, hammering, or pressing; Special equipment or accessories therefor
- B21J5/002—Hybrid process, e.g. forging following casting
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/005—Heat treatment of ferrous alloys containing Mn
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/008—Heat treatment of ferrous alloys containing Si
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/005—Modifying the physical properties by deformation combined with, or followed by, heat treatment of ferrous alloys
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/001—Austenite
Abstract
The invention discloses an austenitic stainless steel forging for spent fuel aftertreatment, which comprises the following components: the stainless steel comprises the following chemical components: less than or equal to 0.03 percent of C, less than or equal to 1.00 percent of Si, 1.70 to 2.00 percent of Mn, less than or equal to 0.03 percent of P, less than or equal to 0.015 percent of S, 18.00 to 20.00 percent of Cr, 9.10 to 12.00 percent of Ni and the balance of iron. Also discloses a manufacturing method of the austenitic stainless steel forging for spent fuel post-treatment, which comprises the following steps: step one, smelting in an electric furnace; step two, refining outside the furnace; step three, forging; step four, heat treatment; step five, performance test; step six, machining step seven, nondestructive testing; and step eight, finishing the product. Through the mode, the raw materials of the invention are refined steel, degassed, greatly reduced in harmful elements such as phosphorus, sulfur and the like, and less in internal defects of steel ingots; adjusting the content of chemical elements, expanding an austenite phase region, increasing the stability of austenite, and reducing the content of high-temperature ferrite in the material; during heat treatment, the austenitizing temperature and the heat preservation time are controlled to form a single austenite structure, so that grains are prevented from growing, and sand pit cooling is adopted for cooling.
Description
Technical Field
The invention relates to the technical field of stainless steel forging, in particular to an austenitic stainless steel forging for spent fuel aftertreatment and a manufacturing method thereof.
Background
Spent fuel, also known as irradiated nuclear fuel, is the nuclear fuel that has been burned in a reactor. The nuclear fuel is discharged after a period of time after nuclear reaction in the reactor, the discharged nuclear fuel contains a large amount of valuable materials uranium 238 and thorium 232, and the unburned and valuable nuclear elements can be recycled after post-treatment. The recycling of the nuclear fuel can not only increase the utilization efficiency of the nuclear fuel, but also reduce the pressure of deep burying treatment and safe maintenance of the waste nuclear fuel.
The forging for the spent fuel post-treatment equipment is mainly made of 022Cr19Ni10, is a mark in GB/T20878, and is also frequently used in the national forging standard. The spent fuel post-treatment is the most critical link for recycling the nuclear fuel, after the nuclear power in China is rapidly developed for decades, more and more units are operated in service, the production amount of the spent fuel is increased, but the construction of the spent fuel post-treatment is just started at present, and the process and the technology of the spent fuel post-treatment are not mature. At present, the state accelerates the post-treatment construction of the spent fuel, the work of the spent fuel post-treatment demonstration project of the Zhongrongyi science and technology Limited company is already carried out, and after the technology and the process are mature, the spent fuel post-treatment industry can be rapidly developed.
The spent fuel of the nuclear power station belongs to a high-radioactive substance, a large amount of decay heat can be continuously released outwards during post-treatment or storage, equipment for post-treatment or storage of the spent fuel is in a high-temperature and high-radioactivity working condition and has high danger, and once nuclear leakage occurs in the post-treatment equipment and the storage equipment, great influence is generated domestically and internationally, and the living environment of human beings is endangered. A large amount of austenitic stainless steel forgings are used in spent fuel post-treatment equipment, and due to special safety requirements, the austenitic stainless steel used in a spent fuel treatment project has the performances specified in material standards, and the forgings are required to have extremely high reliability, stability and high-temperature irradiation resistance.
Nuclear energy is a clean energy, fossil energy is gradually eliminated under the condition of increasingly serious environmental pollution, and the proportion of the nuclear energy in the energy is gradually enlarged. The nuclear energy of China develops for decades, a large number of nuclear power units are built, but the nuclear power generation only accounts for 4% of the total generated energy at present in China, and has a certain gap with the average level of developed countries or the world, and the number of nuclear power units will continue to increase in the future. The spent fuel generated during the operation of the nuclear power station is a dangerous substance, the spent fuel contains more renewable resources, the post-treatment of the spent fuel is an important part in the cyclic utilization of the nuclear fuel, the utilization rate of the nuclear fuel is improved, and the pressure of deep-burying disposal of nuclear waste is reduced. The construction of the spent fuel post-treatment is expected to meet the rapid development period in the future, and the demand of stainless steel forgings for the spent fuel post-treatment is expected to increase continuously.
Disclosure of Invention
The invention mainly solves the technical problem of providing an austenitic stainless steel forging for spent fuel aftertreatment, which can meet the performance requirement in the spent fuel aftertreatment use.
In order to achieve the purpose, the technical scheme adopted by the invention for solving the technical problems is as follows:
an austenitic stainless steel forging for spent fuel reprocessing, comprising: the stainless steel comprises the following chemical components: less than or equal to 0.03 percent of C, less than or equal to 1.00 percent of Si, 1.70 to 2.00 percent of Mn, less than or equal to 0.03 percent of P, less than or equal to 0.015 percent of S, 18.00 to 20.00 percent of Cr, 9.10 to 12.00 percent of Ni and the balance of iron.
A manufacturing method of an austenitic stainless steel forging for spent fuel post-treatment comprises the following steps:
step one, smelting in an electric furnace: smelting furnace burden into primary molten steel in an electric furnace;
step two, refining outside the furnace: refining the molten steel obtained in the first step into the stainless steel by using a refining furnace, and casting the molten steel into a steel ingot after refining;
step three, forging: forging the stainless steel ingot obtained in the second step into a product forging by using a hydraulic press or an air hammer;
step four, heat treatment: placing the forge piece naturally cooled in the third step into a resistance furnace for solution treatment;
step five, performance test: after the heat treatment, cutting test samples from the forged piece subjected to the heat treatment in the fourth step, processing the test samples into tensile samples and impact samples, and performing mechanical property tests;
step six, machining: machining the forged piece qualified in the mechanical property test in the fifth step into a stainless steel flange and a forged piece workpiece;
step seven, nondestructive testing: flaw detection and inspection are carried out on the machined workpiece through an ultrasonic flaw detector and a magnetic particle flaw detector;
step eight, finished product: and packaging and warehousing the flaw-detected and inspected workpieces.
Preferably, the forging heating equipment in the third step is a natural gas heating furnace, the heating temperature is less than or equal to 1200 ℃, and the heat preservation time is 1.5-2 h.
Preferably, the forging process in the third step has the initial forging temperature of less than or equal to 1200 ℃ and the final forging temperature of more than or equal to 800 ℃.
Preferably, the total forging ratio of the forging process in the third step is more than or equal to 3, the deformation of the last fire is more than or equal to 20% of the total deformation, and the sand pit is cooled to room temperature after forging.
Preferably, the temperature of the solid solution treatment adopted in the heat treatment process in the fourth step is 1050-1120 ℃, the liquid medium is cooled, and the heat preservation time of the solid solution treatment is less than or equal to 4 hours.
Due to the application of the technical scheme, compared with the prior art, the invention has the following beneficial effects:
(1) the raw materials are refined steel and degassed, harmful elements such as phosphorus, sulfur and the like are greatly reduced, and the internal defects of steel ingots are few.
(2) The chemical element content is adjusted, and the austenite phase region is enlarged, the austenite stability is increased, and the high-temperature ferrite content in the material is reduced by reasonably matching the element content.
(3) The forging heating temperature is controlled to be less than or equal to 1200 ℃, and high-temperature ferrite is prevented from being formed in the forging heating. And during forging, forging process parameters are controlled, a dynamic recrystallization effect is formed inside the forging, and crystal grains are refined.
(4) The heat treatment adopts a solution treatment mode, the austenitizing temperature and the heat preservation time are controlled, a single austenite structure is formed, the growth of crystal grains is prevented, and the cooling adopts sand pit cooling.
Drawings
FIG. 1 is a flow chart of a method for manufacturing an austenitic stainless steel forging for spent fuel reprocessing according to the present invention.
FIG. 2 is a photograph showing the grain size measured in example 1 of the present invention.
FIG. 3 is a photograph showing nonmetallic inclusions measured in example 1 of the present invention.
Detailed Description
The following detailed description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings, will make the advantages and features of the invention easier to understand by those skilled in the art, and thus will clearly and clearly define the scope of the invention.
The invention discloses an austenitic stainless steel forging for post-treatment of spent fuel, which comprises the following components in percentage by weight: the stainless steel comprises the following chemical components: less than or equal to 0.03 percent of C, less than or equal to 1.00 percent of Si, 1.70 to 2.00 percent of Mn, less than or equal to 0.03 percent of P, less than or equal to 0.015 percent of S, 18.00 to 20.00 percent of Cr, 9.10 to 12.00 percent of Ni and the balance of iron. The contents of Cr, Ni and Mn are optimized, and the corrosion resistance and the material strength are improved. The non-metallic inclusions in the raw material are limited, and the thickness and the fineness of A, B, C, D, Ds-type inclusions are respectively not more than 1.0 grade according to GB/T10561 detection.
FIG. 1 is a flow chart of a method of manufacturing an austenitic stainless steel forging for spent fuel reprocessing of the present invention.
As shown in fig. 1, a method for manufacturing an austenitic stainless steel forging for spent fuel reprocessing includes the following steps:
step one, smelting in an electric furnace: smelting furnace burden into primary molten steel in an electric furnace;
step two, refining outside the furnace: refining the molten steel obtained in the first step into the stainless steel by using a refining furnace, and casting the molten steel into a steel ingot after refining;
the specific steps of the stainless steel generation in the second step are as follows: the molten steel flows into a refining furnace and enters a reduction stage for smelting, firstly, silico-calcium alloy powder or calcium carbide powder is blown into the molten steel, then, silico-ferromanganese, ferrochromium and rare earth alloy are firstly added, meanwhile, nitrogen is blown into the molten steel, and then, the rare earth alloy is added, wherein the ratio of rare earth to sulfur is controlled to be 1-2.5.
Step three, forging: forging the stainless steel ingot obtained in the step two into a product forging by using a hydraulic press or an air hammer;
the forging heating equipment is a natural gas heating furnace, the heating temperature is less than or equal to 1200 ℃, and the temperature is preserved after heating. When the austenitic stainless steel is heated to more than 1200 ℃, delta ferrite is generated in the structure, and the delta ferrite is transformed into a sigma phase when being used for a long time under the high-temperature working condition, so that the material becomes brittle.
The initial forging temperature of the forging process is less than or equal to 1200 ℃, and the final forging temperature is more than or equal to 800 ℃. In order to further reduce the defects in the forged piece and increase the removal amount of a steel ingot riser and a water gap, the steel ingot riser end is removed by 15%, and the water gap end is removed by 5%. The forging main deformation is controlled within the temperature range of 980-1100 ℃, the blank is fully forged to be solid, the as-cast structure is eliminated, and the small defects are forged. Controlling the total forging ratio to be not less than 3, controlling the last fire deformation to be not less than 20% of the total deformation, and cooling the forged steel in a sand pit to room temperature.
Specifically, the forging can be carried out in three times, the first time is carried out for steel ingot chamfering, drawing, hot cutting of a riser and a water gap, and the forging ratio is about 2; upsetting and drawing out the steel ingot for the second heating time, wherein the forging ratio is about 3; the third heating is upsetting or drawing to a specified shape, and the forging ratio is about 3; the total forging ratio of the three fire times is 8, the deformation of the last fire is 37.5 percent, and the sand pit is slowly cooled after forging.
Step four, heat treatment: placing the forge piece naturally cooled in the third step into a resistance furnace for solution treatment;
the key point of the solution treatment is rapid cooling to form a single austenite structure and prevent the structure from being precipitated. In order to achieve good solution treatment effect, the solution treatment temperature adopted in the heat treatment process is 1050-1120 ℃. Cooling the liquid medium by using a large water pool and rapidly circulating the liquid medium with an external water storage pool, wherein the external dimension of the liquid medium is as close to the product dimension as possible during heat treatment. The heat preservation time of the solution treatment is less than or equal to 4 hours, and the austenite grains are prevented from growing too fast during heat treatment and heating.
Step five, performance test: after the heat treatment, cutting test samples from the forged piece subjected to the heat treatment in the step four, processing the test samples into tensile samples and impact samples, and performing mechanical property tests;
step six, machining: machining the forged piece qualified in the mechanical property test in the fifth step into a stainless steel flange and a forged piece workpiece;
step seven, nondestructive testing: flaw detection and inspection are carried out on the machined workpiece through an ultrasonic flaw detector and a magnetic particle flaw detector;
step eight, finished product: and packaging and warehousing the flaw-detected and inspected workpieces.
The invention is specifically illustrated below with reference to specific examples:
example 1: A500X 252X 117mm spent fuel post-treatment steam jet pump forging is made of 022Cr19Ni10 austenitic stainless steel. The acceptance requirement is that the austenite grain size is less than or equal to 5 grade; magnetic powder detection and ultrasonic detection are carried out according to NB/T47013.5, and grade 1 is qualified; the mechanical properties of the alloy meet the requirements of table 1:
TABLE 1 requirements to be met by mechanical Properties
The specific process flow is as follows:
raw material smelting → blanking → forging → heat treatment → sampling → performance test → nondestructive testing → machining → finished product.
2 tons of square steel ingots are used as raw materials, and 5 spent fuel post-treatment steam jet pump forgings are manufactured from one steel ingot. The chemical components of the steel ingot are shown in a table 2:
table 2 chemical composition%
| Material of | C | Si | Mn | P | S | Cr | Ni |
| 022Cr19Ni10 | 0.028 | 0.52 | 1.72 | 0.021 | 0.003 | 18.55 | 9.22 |
Heating the steel ingot by using a natural gas heating furnace, forging and cogging the steel ingot on a 3600-ton hydraulic press after the steel ingot is heated and discharged, lightly pressing, chamfering and drawing out the steel ingot by using a first fire, finally forging the steel ingot into a round billet with the diameter of 300mm, cooling the round billet to room temperature, and sawing and blanking the round billet. Two ends of a round billet forged by a steel ingot are provided with a riser and a nozzle, the cutting length of the riser is 540mm, the cutting length of the nozzle is 180mm, the middle part of the round billet is provided with 5 forging billets, and each billet is forged into a spent fuel post-treatment steam jet pump forging product.
Heating the blank in a natural gas heating furnace, heating to 800 ℃ along with the furnace, preserving heat for 0.5 hour, heating to 1180 ℃ along with the furnace, preserving heat for 1 hour, and then starting forging: upsetting to 242mm in height, upsetting ratio to 2, and then drawing to 485mm in height, drawing ratio to 2. Then, the steel plate was square-shaped to a predetermined size at a forging ratio of 1.2. The total forging ratio was 5.2. The forging main deformation should be controlled in the temperature range of 980-1100 ℃. After forging, the material was cooled to room temperature in a sand pit.
And (3) loading the forged workpiece into a heat treatment furnace, keeping the temperature for 3.5 hours at the solution treatment temperature of 1080 ℃, and cooling by water.
And after the heat treatment is finished, selecting a forging piece in each batch, intercepting test materials on the forging piece, intercepting various samples on the samples, and performing detection items of mechanical properties, grain size, inclusions and the like. The measured mechanical property data are shown in Table 3, wherein A represents the growth rate and Z represents the reduction of area.
TABLE 3 mechanical Properties test
The grain size is measured according to GB/T6394 metal average grain size measurement method, and the grade of the grain size is 5.5. The grain size picture is shown in figure 2.
And machining the forge piece after the mechanical property test, wherein the machining aims to prepare for subsequent nondestructive testing, and the nondestructive testing items are ultrasonic testing and magnetic powder testing. No defect with equivalent weight larger than 2mm is found in ultrasonic detection, no circular defect with equivalent weight larger than 1mm is found in magnetic powder detection, no linear defect is found, the thickness and the fineness of various non-metallic inclusions are smaller than 1 grade, and the grade 1 is qualified. The picture of the nonmetallic inclusion is shown in FIG. 3.
Comparative example 1: manufacturing a 500X 252X 117mm spent fuel post-treatment steam jet pump forging made of 022Cr19Ni10 austenitic stainless steel, wherein the chemical components of the stainless steel are traditional chemical components, and concretely, see Table 4, the process method of the embodiment 1 is adopted;
TABLE 4 chemical composition%
| Material of | C | Si | Mn | P | S | Cr | Ni |
| 022Cr19Ni10 | 0.021 | 0.42 | 1.22 | 0.032 | 0.013 | 17.20 | 9.08 |
And after the heat treatment is finished, selecting a forging piece in each batch, intercepting test materials on the forging piece, intercepting various samples on the samples, and performing detection items of mechanical properties, grain size, inclusions and the like. The measured mechanical property data are shown in Table 5, wherein A represents the growth rate and Z represents the reduction of area.
TABLE 5 mechanical Properties test
| Material of | Rm(MPa) | Rp0.2(MPa) | A(％) | Z(％) | Akv2(J) |
| 022Cr19Ni10 | 549 | 251 | 60.5 | 69 | 266 |
The grain size is measured according to GB/T6394 metal average grain size measuring method, and the grade of the grain size is 5.
And machining the forge piece after the mechanical property test, wherein the machining aims to prepare for subsequent nondestructive testing, and the nondestructive testing items are ultrasonic testing and magnetic powder testing. No defect with equivalent weight larger than 2mm is found in ultrasonic detection, no circular defect exceeding 1mm is found in magnetic powder detection, and no linear defect is found.
Comparative example 2: manufacturing a 500X 252X 117mm spent fuel post-treatment steam jet pump forging made of 022Cr19Ni10 austenitic stainless steel, wherein the chemical components of the stainless steel are the chemical components in the embodiment 1, and the specific chemical components are shown in Table 6; the manufacturing method adopts the traditional manufacturing method;
TABLE 6 chemical composition%
| Material of | C | Si | Mn | P | S | Cr | Ni |
| 022Cr19Ni10 | 0.028 | 0.52 | 1.72 | 0.021 | 0.003 | 18.55 | 9.22 |
The traditional manufacturing method is used, and the content of the traditional manufacturing method is as follows:
and heating the steel ingot in a natural gas heating furnace at the heating and heat preservation temperature of 1260 ℃, the heat preservation time of 2 hours, the initial forging temperature of 1240 ℃, the final forging temperature of more than or equal to 800 ℃, forging by two fire times with the total forging ratio of 3.5, and air cooling after forging.
During heat treatment, the solution treatment temperature is 1120 ℃, the heat preservation is carried out for 4.5 hours, the liquid medium is cooled, the tempering temperature is 710 ℃, and air cooling is carried out.
And after the heat treatment is finished, selecting a forging piece in each batch, intercepting test materials on the forging piece, intercepting various samples on the samples, and performing detection items of mechanical properties, grain size, inclusions and the like. The measured mechanical property data are shown in Table 7, wherein A represents the growth rate and Z represents the reduction of area.
TABLE 7 mechanical Properties test
| Material of | Rm(MPa) | Rp0.2(MPa) | A(％) | Z(％) | Akv2(J) |
| 022Cr19Ni10 | 518 | 225 | 36 | 55 | 165 |
The grain size is measured according to GB/T6394 metal average grain size measurement method, and the grain size grade is 3.0 grade.
And machining the forge piece after the mechanical property test, wherein the machining aims to prepare for subsequent nondestructive testing, and the nondestructive testing items are ultrasonic testing and magnetic powder testing. In ultrasonic detection, a plurality of defects with the size larger than 2mm are found, but the defect equivalent is smaller than NB/T47013 II grade, and the standard requirements are met. The magnetic powder test did not find circular defects exceeding 1mm, and any linear defects were not seen.
Comparing example 1 of the present invention with comparative examples 1, 2, the following conclusions were made:
for comparative example 1, the mechanical property index was reduced due to the use of the conventional chemical components, indicating that the chemical component adjustment produces a better effect on the improvement of the mechanical properties. Since other preparation methods than the chemical composition were not changed, the grain size, surface defects and internal defects of the product were not much different from those of the examples.
For the comparative example 2, the chemical components in the example are adopted, but because the forging process of the traditional process has no dynamic recrystallization effect, the heating temperature of the heat treatment is higher, the austenite grains are obviously increased, the mechanical property is obviously reduced compared with the example, and the manufacturing process adjustment has a better effect on the improvement of the mechanical property. Because the forging of the traditional process is smaller, the forging and compacting effects of the forging are not good, and a plurality of defects larger than 2mm are found during ultrasonic detection.
The detection data show that the forged piece produced by using the stainless steel composition and the manufacturing method has excellent performance, the performance index of the forged piece is far higher than that of the forged piece produced by the traditional process, the number and the size of defects found in nondestructive testing of the forged piece are also far better than those of the traditional process, the embodiment process has better effect than the traditional process, and the embodiment composition has better mechanical property than the traditional chemical composition.
The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (6)
1. An austenitic stainless steel forging for spent fuel reprocessing, comprising: the stainless steel comprises the following chemical components: less than or equal to 0.03 percent of C, less than or equal to 1.00 percent of Si, 1.70 to 2.00 percent of Mn, less than or equal to 0.03 percent of P, less than or equal to 0.015 percent of S, 18.00 to 20.00 percent of Cr, 9.10 to 12.00 percent of Ni and the balance of iron.
2. The manufacturing method of the austenitic stainless steel forging for the post-treatment of the spent fuel is characterized by comprising the following steps of:
step one, smelting in an electric furnace: smelting furnace burden into primary molten steel in an electric furnace;
step two, refining outside the furnace: refining the molten steel obtained in the first step into the stainless steel in the right 1 by using a refining furnace, and casting the molten steel into a steel ingot after refining;
step three, forging: forging the stainless steel ingot obtained in the second step into a product forging by using a hydraulic press or an air hammer;
step four, heat treatment: placing the forge piece naturally cooled in the third step into a resistance furnace for solution treatment;
step five, performance test: after the heat treatment, cutting test samples from the forged piece subjected to the heat treatment in the fourth step, processing the test samples into tensile samples and impact samples, and performing mechanical property tests;
step six, machining: machining the forged piece qualified in the mechanical property test in the fifth step into a stainless steel flange and a forged piece workpiece;
step seven, nondestructive testing: flaw detection and inspection are carried out on the machined workpiece through an ultrasonic flaw detector and a magnetic particle flaw detector;
step eight, finished product: and packaging and warehousing the flaw-detected and inspected workpieces.
3. The method for manufacturing the austenitic stainless steel forging for the spent fuel reprocessing according to claim 2, characterized in that: the forging heating equipment in the third step is a natural gas heating furnace, the heating temperature is less than or equal to 1200 ℃, and the heat preservation time is 1.5-2 h.
4. The method for manufacturing the austenitic stainless steel forging for the spent fuel reprocessing according to claim 2, characterized in that: the forging process in the third step has the initial forging temperature of less than or equal to 1200 ℃ and the final forging temperature of more than or equal to 800 ℃.
5. The method for manufacturing the austenitic stainless steel forging for the spent fuel reprocessing according to claim 2, characterized in that: the total forging ratio of the forging process in the third step is more than or equal to 3, the final heat deformation is more than or equal to 20% of the total deformation, and the sand pit is cooled to room temperature after forging.
6. The method for manufacturing the austenitic stainless steel forging for the spent fuel reprocessing according to claim 2, characterized in that: in the fourth step, the temperature of the solid solution treatment adopted in the heat treatment process is 1050-1120 ℃, the liquid medium is cooled, and the heat preservation time of the solid solution treatment is less than or equal to 4 hours.
Priority Applications (1)
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| CN112941410A (en) * | 2021-01-29 | 2021-06-11 | 无锡市法兰锻造有限公司 | Method for controlling alpha phase content in austenitic stainless steel |
| CN115747662A (en) * | 2022-11-30 | 2023-03-07 | 山西太钢不锈钢股份有限公司 | Method for refining stainless steel for high-pressure common rail of engine |
| CN115896633A (en) * | 2022-12-13 | 2023-04-04 | 无锡市法兰锻造有限公司 | Manufacturing process of hairline-free austenitic stainless steel forging for nuclear power station |
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