High-temperature-resistant low-oxygen molybdenum alloy plate for fast reactor and preparation method thereof
Through multiple suspension smelting, small deformation forging and cross-rolling processes, the problems of unstable high temperature mechanical properties and excessive oxygen content of molybdenum alloy sheets are solved, and stable mechanical properties and low oxygen content are achieved at high temperatures.
Patent Information
- Application Number
- CN202411531512.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-30
- Publication Date
- 2025-02-07
AI Technical Summary
The mechanical properties of existing molybdenum alloy sheets are unstable at high temperatures, and the excessive oxygen content leads to a decrease in tensile strength and elongation.
Multiple suspension smelting combined with small deformation forging and cross-rolling technology are used to reduce oxygen element content through vacuum suspension smelting, and forging and rolling improve grain density and mechanical properties.
It significantly improves the high-temperature mechanical properties stability of molybdenum alloy sheets, reduces the oxygen content, and improves the tensile strength and elongation.
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Figure CN119392028A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of molybdenum alloys, and in particular relates to a high-temperature resistant low-oxygen molybdenum alloy plate for a fast reactor and a preparation method thereof. Background Art
[0002] The core melting collector is of great significance to the severe accident management of sodium-cooled fast reactors. When selecting the core melting collector material, its strength, toughness, corrosion resistance and radiation embrittlement properties should be considered. Molybdenum alloy is a material for the core melting collector of sodium-cooled fast reactors due to its excellent high temperature properties, good mechanical properties, low thermal expansion coefficient, good thermal conductivity, corrosion resistance and relatively low thermal neutron capture interface.
[0003] The mainstream method for producing molybdenum alloy plates in China is powder metallurgy, but the performance of molybdenum alloy plates produced by powder metallurgy has certain defects: there are a large number of pores inside the molybdenum alloy plates, and oxygen elements are easy to accumulate in the internal pores, which cannot be eliminated and difficult to be reduced, resulting in excessive oxygen content, which makes the tensile strength and elongation of the molybdenum alloy plates sharply reduced, and the distribution dispersion of high-temperature tensile mechanical properties is large, which makes the mechanical properties of molybdenum alloy plates at high temperatures unstable.
[0004] Therefore, it is urgent to develop a preparation method that can reduce the oxygen content of molybdenum alloy plates and improve the high-temperature stability of molybdenum alloy plates. Summary of the invention
[0005] The purpose of the present invention is to overcome the deficiencies in the above-mentioned prior art and provide a method for preparing a high-temperature resistant low-oxygen molybdenum alloy plate for a fast reactor. The preparation method can effectively reduce the oxygen content in the molybdenum alloy plate by using multiple suspension smelting combined with small deformation forging and cross rolling processes, significantly improve the stability of the high-temperature mechanical properties of the molybdenum alloy plate, and solve the problem of excessively high oxygen content and unstable high-temperature mechanical properties of the molybdenum alloy plate prepared in the prior art.
[0006] To achieve the above object, the technical solution adopted by the present invention is: a method for preparing a high temperature resistant low oxygen molybdenum alloy plate for a fast reactor, characterized in that the preparation method comprises the following steps:
[0007] Step 1: Evenly mix molybdenum particles, titanium particles, zirconium particles and carbon particles, and then perform vacuum suspension melting for at least 2 times to form a molybdenum alloy ingot;
[0008] Step 2: grinding the molybdenum alloy ingot obtained in step 1, cutting off the riser, and coating the ingot with a high-temperature antioxidant, heating and heat preservation in a hydrogen atmosphere, and then forging and grinding the ingot to obtain a molybdenum alloy forging blank; wherein the deformation amount of each forging pass is 5% to 10%;
[0009] Step 3, placing the molybdenum alloy forging blank obtained in step 2 in a hydrogen atmosphere, heating and heat preservation, and then cross-rolling to obtain a rolled plate;
[0010] Step 4: subjecting the rolled plate obtained in step 3 to annealing heat treatment, and then subjecting it to grinding, alkali washing and polishing to obtain a molybdenum alloy plate.
[0011] The present invention strengthens the molybdenum alloy plate by adding carbon particles, and at the same time, by adopting the suspension smelting process for smelting, the carbon element in the molybdenum alloy can be reduced and deoxidized, reducing the presence of some oxygen elements, thereby reducing the cracking problem caused by the segregation of oxygen elements at the grain boundaries, which causes a large number of holes at the grain boundaries; by adopting small deformation forging to forge the molybdenum alloy ingot, the molybdenum alloy ingot can be sufficiently deformed, and the structure is gradually densified. In addition, since the deformation amount per die is small, it is necessary to perform repeated multi-die forging at high temperature, which can restore the processing stress of the molybdenum alloy ingot, so that the molybdenum alloy ingot has good plasticity and meets the subsequent processing requirements of the molybdenum alloy ingot; dynamic recovery and dynamic recrystallization can be generated by performing multiple cross-rolling. Combining the above-mentioned suspension smelting, small deformation forging and cross-rolling processes, the high-temperature mechanical property stability of the molybdenum alloy plate is effectively improved.
[0012] The high temperature antioxidant used in step 2 of the present invention is a graphite high temperature antioxidant, and the polishing process in step 4 includes cleaning the metal surface to remove oil and impurities, rough grinding, fine grinding, polishing and cleaning.
[0013] The above-mentioned method for preparing a high-temperature resistant low-oxygen molybdenum alloy plate for a fast reactor is characterized in that after each completion of the vacuum suspension smelting in step 1, the obtained smelted ingot is flipped 180° in the vertical direction and then placed in a vacuum suspension smelting furnace.
[0014] The present invention can ensure the density and composition uniformity of the molybdenum alloy smelting ingot by performing multiple smelting and reversing smelting, avoid segregation or uneven distribution of alloy elements such as titanium, zirconium and carbon during suspension smelting, thereby ensuring the performance of the molybdenum alloy plate; at the same time, under the action of strong electromagnetic stirring, oxygen, nitrogen and the like can be separated from metal elements to form bubbles, thereby reducing the content of gas elements such as oxygen and nitrogen and reducing internal stress, thereby improving the stability of the mechanical properties of the molybdenum alloy plate.
[0015] The above-mentioned method for preparing a high-temperature resistant low-oxygen molybdenum alloy plate for a fast reactor is characterized in that the process of vacuum suspension melting in step one is: evacuating the vacuum suspension melting furnace to a vacuum degree not greater than 0.5Pa, filling with argon until the argon pressure reaches 10kPa, and performing vacuum suspension melting after multiple cycles of vacuuming and filling with argon; the power of the vacuum suspension melting is 260kW~280kW, and the time of the vacuum suspension melting is 8min~12min.
[0016] The above-mentioned method for preparing a high-temperature resistant low-oxygen molybdenum alloy plate for a fast reactor is characterized in that the mass purity of the molybdenum particles in step one is not less than 99.95%, and the particle size of the molybdenum particles is 3mm~5mm; the mass purity of the titanium particles is not less than 99.95%, and the particle size of the titanium particles is 3mm~8mm; the mass purity of the zirconium particles is not less than 99.95%, and the particle size of the zirconium particles is 3mm~8mm; the mass purity of the carbon particles is not less than 99.95%, and the particle size of the carbon particles is 1mm~3mm.
[0017] The above-mentioned method for preparing a high-temperature resistant low-oxygen molybdenum alloy plate for a fast reactor is characterized in that the heating temperature in the hydrogen atmosphere in step 2 is 1000°C to 1200°C, the insulation time in the hydrogen atmosphere is 0.5h to 2h, and the cumulative deformation of the forging is 30% to 45%.
[0018] The above-mentioned method for preparing a high-temperature resistant low-oxygen molybdenum alloy plate for a fast reactor is characterized in that the heating temperature in the hydrogen atmosphere in step three is 1000°C to 1200°C, the insulation time in the hydrogen atmosphere is 0.5h to 2h, the first rolling deformation is not less than 20%, and the cumulative rolling deformation is 70% to 90%.
[0019] The present invention controls the deformation amount of the first rolling pass to be not less than 20%, so that the inner and outer layers of the molybdenum alloy plate can be deformed uniformly, and the opening and delamination of the molybdenum alloy plate caused by the small deformation amount of the first rolling pass can be avoided. The deformation cannot penetrate into the middle of the molybdenum alloy slab, and the slab produces serious uneven deformation.
[0020] The above-mentioned method for preparing a high-temperature resistant low-oxygen molybdenum alloy plate for a fast reactor is characterized in that the annealing heat treatment in step 4 is carried out in a hydrogen or argon atmosphere, the temperature of the annealing heat treatment is 1000°C to 1200°C, and the holding time of the annealing heat treatment is 0.5h to 2h.
[0021] In addition, the present invention also discloses a high-temperature resistant low-oxygen molybdenum alloy plate for fast reactor prepared by the above method, characterized in that the oxygen content of the molybdenum alloy plate is not higher than 20 ppm, the nitrogen content is not higher than 20 ppm, and the carbon content is not higher than 40 ppm.
[0022] The above-mentioned high-temperature resistant low-oxygen molybdenum alloy plate for fast reactor is characterized in that the tensile strength of the molybdenum alloy plate at 20°C is not less than 740MPa, the yield strength is not less than 600MPa, and the elongation is not less than 35%; the tensile strength of the molybdenum alloy plate at 1200°C is not less than 230MPa, the yield strength is not less than 130MPa, and the elongation is not less than 20%; the tensile strength of the molybdenum alloy plate at 1500°C is not less than 120MPa, the yield strength is not less than 90MPa, and the elongation is not less than 25%.
[0023] The above-mentioned high-temperature resistant low-oxygen molybdenum alloy plate for fast reactor is characterized in that the extreme difference in tensile strength of the molybdenum alloy plate of the same batch at 20°C, 1200°C and 1500°C is no more than 15MPa, and the extreme difference in elongation is no more than 3%.
[0024] Compared with the prior art, the present invention has the following advantages:
[0025] 1. The present invention adopts a vacuum suspension melting furnace to prepare molybdenum alloy ingots, so that the alloy liquid is suspended in the crucible, eliminating the pollution of the alloy liquid by the traditional melting method, which is beneficial to improving the purity of the alloy liquid, and the strong magnetic stirring effect effectively reduces the content of oxygen and nitrogen elements, so that the tensile strength and elongation of the molybdenum alloy material are improved, and the machinability of the molybdenum alloy plate is increased; by adopting small deformation continuous forging during forging, the formation of forging dead zone is avoided, and the grains of the molybdenum alloy smelting ingot are effectively refined, and the cross-rolling is combined to effectively reduce the anisotropy of the molybdenum alloy plate, and the performance is more uniform; in summary, combined with multiple suspension melting, small deformation forging and cross-rolling processes, the oxygen content in the molybdenum alloy plate is reduced, and the high-temperature mechanical property stability of the molybdenum alloy plate is significantly improved.
[0026] 2. The present invention uses metal particles with low oxygen content as raw materials and adopts a hydrogen reducing atmosphere in the subsequent forging, rolling and annealing processes. Due to the chemical composition and structural characteristics of the molybdenum alloy, it has high stability in a hydrogen environment, thereby inhibiting the oxidation process of the molybdenum alloy; by applying a high-temperature antioxidant, contact with air is avoided, thereby reducing the oxygen content of the finished molybdenum alloy plate.
[0027] 3. The molybdenum alloy plate prepared by the present invention has good and stable tensile mechanical properties under 20°C, 1200°C and 1500°C environments.
[0028] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Figure 1 This is the metallographic diagram of the molybdenum alloy plate prepared in Example 1 of the present invention.
[0030] Figure 2 This is a microscopic morphology of the molybdenum alloy plate prepared in Example 1 of the present invention.
[0031] Figure 3 This is the molybdenum element distribution diagram of the molybdenum alloy plate prepared in Example 1 of the present invention.
[0032] Figure 4 This is the titanium element distribution diagram of the molybdenum alloy plate prepared in Example 1 of the present invention.
[0033] Figure 5 This is the zirconium element distribution diagram of the molybdenum alloy plate prepared in Example 1 of the present invention. DETAILED DESCRIPTION
[0034] Example 1
[0035] The preparation method of this embodiment comprises the following steps:
[0036] Step 1, 5kg of molybdenum particles, 15g of titanium particles, 7.5g of zirconium particles and 0.2g of carbon particles are mixed evenly and then vacuum suspended smelting is performed three times to form a molybdenum alloy ingot; the process of the vacuum suspension smelting is as follows: the vacuum suspension smelting furnace is evacuated to a vacuum degree of no more than 0.5Pa, argon is filled until the argon pressure reaches 10kPa, and vacuum suspension smelting is performed after multiple cycles of vacuum evacuation and argon filling. After completion, the obtained smelted ingot is turned 180° in the vertical direction and then placed in the vacuum suspension smelting furnace again for the next vacuum suspension smelting; the power of the vacuum suspension smelting is 270kW, and the time of the vacuum suspension smelting is 10min; the mass purity of the molybdenum particles is 99.95% and the particle size is 3mm, the mass purity of the titanium particles is 99.95% and the particle size is 5mm, the mass purity of the zirconium particles is 99.95% and the particle size is 7mm, and the mass purity of the carbon particles is 99.95% and the particle size is 1mm;
[0037] Step 2: grinding the molybdenum alloy ingot obtained in step 1, cutting off the riser, and coating the ingot with a high-temperature antioxidant, heating it to 1100° C. in a hydrogen atmosphere for 1 hour, and then forging and grinding it to obtain a molybdenum alloy forging blank; the deformation amount of each forging is 5%, and the cumulative deformation amount of the forging is 30%;
[0038] Step 3, the molybdenum alloy forging blank obtained in step 2 is placed in a hydrogen atmosphere, heated to 1100° C., kept warm for 1 hour, and then cross-rolled to obtain a rolled plate; the first rolling deformation is 25%, and the cumulative rolling deformation is 85%;
[0039] Step 4: subjecting the rolled plate obtained in step 3 to annealing heat treatment, and then grinding, alkali washing and polishing to obtain a molybdenum alloy plate; the annealing heat treatment is carried out in a hydrogen atmosphere, the annealing heat treatment temperature is 1100° C., and the annealing heat treatment holding time is 0.5 h.
[0040] According to the preparation method of this embodiment, three batches of molybdenum alloy plates were prepared. The oxygen, nitrogen and carbon content of the three batches of molybdenum alloy plates were measured, and the tensile mechanical properties were tested at 20°C, 1200°C and 1500°C. The test results are shown in Tables 1 to 4.
[0041] Table 1 Element contents of 3 batches of molybdenum alloy plates in this example
[0042] batch Oxygen content / ppm Nitrogen content / ppm Carbon content / ppm 1 18 19 10 2 19 16 14 3 18 18 20
[0043] Table 2 20℃ tensile properties of 3 batches of molybdenum alloy plates in this example
[0044] batch Tensile strength / MPa Yield strength / MPa Elongation / % 1 755 629 37.5 2 753 623 36.5 3 745 607 35.5 Very bad 10 / 2.0
[0045] Table 3 1200℃ tensile properties of 3 batches of molybdenum alloy plates in this example
[0046] batch Tensile strength / MPa Yield strength / MPa Elongation / % 1 241.0 136.7 20.4 2 241.9 132.5 22.9 3 238.6 130.6 21.4 Very bad 3.3 / 2.5
[0047] Table 4 1500℃ tensile properties of 3 batches of molybdenum alloy plates in this example
[0048] batch Tensile strength / MPa Yield strength / MPa Elongation / % 1 128.3 91.6 27.1 2 130.3 92.5 25.9 3 133.3 93.4 27.1 Very bad 5.0 / 1.2
[0049] It can be seen from Table 1 that the oxygen content of the three batches of molybdenum alloy plates is not more than 20ppm, the nitrogen content is not more than 20ppm, and the carbon content is not more than 40ppm; it can be seen from Table 2 that the tensile strength of the three batches of molybdenum alloy plates at 20°C is greater than 740MPa, the range of tensile strength is 10MPa, the yield strength is greater than 600MPa, the elongation is not less than 35%, and the range of elongation is 2.0%; it can be seen from Table 3 that the three batches of molybdenum alloy plates At 1200°C, the tensile strength is greater than 230MPa, the range of tensile strength is 3.3MPa, the yield strength is greater than 130MPa, the elongation is not less than 20%, and the range of elongation is 2.5%; as can be seen from Table 4, the tensile strength of the three batches of molybdenum alloy plates at 1500°C is greater than 120MPa, the range of tensile strength is 5.0MPa, the yield strength is greater than 90MPa, the elongation is not less than 25%, and the range of elongation is 1.2%.
[0050] The metallographic structure of the molybdenum alloy plate prepared in this embodiment is analyzed. Figure 1As shown in the figure, the internal grains of the molybdenum alloy plate are fine, which helps to improve the mechanical properties of the molybdenum alloy plate. The element distribution analysis of the molybdenum alloy plate is carried out, such as Figure 2 to Figure 5 As shown, the surface of the molybdenum alloy plate is smooth without defects such as pores, and the molybdenum, titanium and zirconium elements inside are evenly distributed.
[0051] In summary, the molybdenum alloy plate prepared in this embodiment has fine grains and uniform element distribution, wherein the oxygen and nitrogen contents are not more than 20 ppm, the carbon content is not more than 40 ppm, and it has good and stable tensile properties at 20°C, 1200°C, and 1500°C.
[0052] Example 2
[0053] The preparation method of this embodiment comprises the following steps:
[0054] Step 1, 5kg of molybdenum particles, 7.5g of titanium particles, 3.5g of zirconium particles and 0.1g of carbon particles are mixed evenly and then vacuum suspended for 3 times to form a molybdenum alloy ingot; the process of the vacuum suspension smelting is: evacuate the vacuum suspension smelting furnace to a vacuum degree of no more than 0.5Pa, fill it with argon until the argon pressure reaches 10kPa, and perform vacuum suspension smelting after multiple cycles of vacuum evacuation and argon filling. After completion, the obtained smelted ingot is turned 180° in the vertical direction and then placed in the vacuum suspension smelting furnace again for the next vacuum suspension smelting; the power of the vacuum suspension smelting is 260kW, and the time of the vacuum suspension smelting is 12min; the mass purity of the molybdenum particles is 99.95% and the particle size is 3mm, the mass purity of the titanium particles is 99.95% and the particle size is 8mm, the mass purity of the zirconium particles is 99.95% and the particle size is 8mm, and the mass purity of the carbon particles is 99.95% and the particle size is 1mm;
[0055] Step 2: grinding the molybdenum alloy ingot obtained in step 1, cutting off the riser, and coating the ingot with a high-temperature antioxidant, heating it to 1200° C. in a hydrogen atmosphere for 0.5 h, and then forging and grinding it to obtain a molybdenum alloy forging blank; the deformation amount of each forging is 10%, and the cumulative deformation amount of the forging is 45%;
[0056] Step 3, the molybdenum alloy forging blank obtained in step 2 is placed in a hydrogen atmosphere, heated to 1200° C., kept warm for 0.5 h, and then cross-rolled to obtain a rolled plate; the first rolling deformation is 20%, and the cumulative rolling deformation is 70%;
[0057] Step 4: subjecting the rolled plate obtained in step 3 to annealing heat treatment, and then performing grinding, alkali washing and polishing to obtain a molybdenum alloy plate; the annealing heat treatment is performed in a hydrogen atmosphere, the annealing heat treatment temperature is 1200° C., and the annealing heat treatment holding time is 0.5 h.
[0058] According to the preparation method of this embodiment, three batches of molybdenum alloy plates were prepared. The oxygen, nitrogen and carbon content of the three batches of molybdenum alloy plates were measured, and the tensile mechanical properties were tested at 20°C, 1200°C and 1500°C. The test results are shown in Tables 5 to 8.
[0059] Table 5 Element contents of 3 batches of molybdenum alloy plates in this embodiment
[0060] batch Oxygen content / ppm Nitrogen content / ppm Carbon content / ppm 1 15 18 32 2 19 20 15 3 17 15 18
[0061] Table 6 20℃ tensile properties of 3 batches of molybdenum alloy plates in this example
[0062] batch Tensile strength / MPa Yield strength / MPa Elongation / % 1 750 615 35.4 2 746 611 36.5 3 749 616 36.5 Very bad 4 / 1.1
[0063] Table 7 1200℃ tensile properties of 3 batches of molybdenum alloy plates in this example
[0064] batch Tensile strength / MPa Yield strength / MPa Elongation / % 1 236.7 136.3 21.3 2 242.3 135.9 21.6 3 235.0 138.4 20.6 Very bad 7.3 / 1.0
[0065] Table 8 1500℃ tensile properties of 3 batches of molybdenum alloy plates in this example
[0066] batch Tensile strength / MPa Yield strength / MPa Elongation / % 1 123.2 94.1 26.3 2 127.4 91.2 25.9 3 133.5 95.6 26.8 Very bad 10.3 / 0.9
[0067] It can be seen from Table 5 that the oxygen content of the three batches of molybdenum alloy plates is not more than 20ppm, the nitrogen content is not more than 20ppm, and the carbon content is not more than 40ppm; it can be seen from Table 6 that the tensile strength of the three batches of molybdenum alloy plates at 20°C is greater than 740MPa, the range of tensile strength is 4MPa, the yield strength is greater than 600MPa, the elongation is not less than 35%, and the range of elongation is 1.1%; it can be seen from Table 7 that the three batches of molybdenum alloy plates have a tensile strength of more than 740MPa at 20°C, the range of tensile strength is 4MPa, the yield strength is greater than 600MPa, the elongation is not less than 35%, and the range of elongation is 1.1%. The tensile strength at 1200°C is greater than 230MPa, the range of tensile strength is 7.3MPa, the yield strength is greater than 130MPa, the elongation is not less than 20%, and the range of elongation is 1.0%; as shown in Table 8, the tensile strength of the three batches of molybdenum alloy plates at 1500°C is greater than 120MPa, the range of tensile strength is 10.3MPa, the yield strength is greater than 90MPa, the elongation is not less than 25%, and the range of elongation is 0.9%.
[0068] In summary, the oxygen and nitrogen contents of the molybdenum alloy plate prepared in this embodiment are not more than 20 ppm, and the carbon content is not more than 40 ppm; the molybdenum alloy plate prepared in this embodiment has good tensile properties at 20°C, 1200°C, and 1500°C, and the tensile properties are stable.
[0069] Example 3
[0070] The preparation method of this embodiment comprises the following steps:
[0071] Step 1, 5kg of molybdenum particles, 15g of titanium particles, 5g of zirconium particles and 0.2g of carbon particles are mixed evenly and then vacuum suspended for 3 times to form a molybdenum alloy ingot; the process of vacuum suspension smelting is: evacuate the vacuum suspension smelting furnace to a vacuum degree of no more than 0.5Pa, fill with argon until the argon pressure reaches 10kPa, and perform vacuum suspension smelting after multiple cycles of vacuum evacuation and argon filling. After completion, the obtained smelted ingot is turned 180° in the vertical direction and then placed in the vacuum suspension smelting furnace again for the next vacuum suspension smelting; the power of the vacuum suspension smelting is 280kW, and the time of the vacuum suspension smelting is 8min; the mass purity of the molybdenum particles is 99.95% and the particle size is 5mm, the mass purity of the titanium particles is 99.97% and the particle size is 3mm, the mass purity of the zirconium particles is 99.96% and the particle size is 3mm, and the mass purity of the carbon particles is 99.95% and the particle size is 1mm;
[0072] Step 2: grinding the molybdenum alloy ingot obtained in step 1, cutting off the riser, and coating the ingot with a high-temperature antioxidant, heating it to 1000° C. in a hydrogen atmosphere for 2 hours, and then forging and grinding it to obtain a molybdenum alloy forging blank; the deformation amount of each forging is 5%, and the cumulative deformation amount of the forging is 30%;
[0073] Step 3, the molybdenum alloy forging blank obtained in step 2 is placed in a hydrogen atmosphere, heated to 1000° C., kept warm for 2 hours, and then cross-rolled to obtain a rolled plate; the first rolling deformation is 25%, and the cumulative rolling deformation is 90%;
[0074] Step 4: subjecting the rolled plate obtained in step 3 to annealing heat treatment, and then performing grinding, alkali washing and polishing to obtain a molybdenum alloy plate; the annealing heat treatment is performed in a hydrogen atmosphere, the annealing heat treatment temperature is 1200° C., and the annealing heat treatment holding time is 0.5 h.
[0075] According to the preparation method of this embodiment, three batches of molybdenum alloy plates were prepared. The oxygen, nitrogen and carbon content of the three batches of molybdenum alloy plates were measured, and the tensile mechanical properties were tested at 20°C, 1200°C and 1500°C. The test results are shown in Tables 9 to 12.
[0076] Table 9 Element contents of 3 batches of molybdenum alloy plates in this example
[0077] batch Oxygen content / ppm Nitrogen content / ppm Carbon content / ppm 1 13 16 30 2 16 17 36 3 19 19 25
[0078] Table 10 20℃ tensile properties of 3 batches of molybdenum alloy plates in this example
[0079] batch Tensile strength / MPa Yield strength / MPa Elongation / % 1 741 628 37.2 2 752 624 36.4 3 745 614 35.5 Very bad 11 / 1.7
[0080] Table 11 1200℃ tensile properties of 3 batches of molybdenum alloy plates in this example
[0081] batch Tensile strength / MPa Yield strength / MPa Elongation / % 1 234.7 132.9 21.3 2 235.2 131.4 22.5 3 238.6 135.7 20.7 Very bad 3.9 / 1.8
[0082] Table 12 1500℃ tensile properties of 3 batches of molybdenum alloy plates in this example
[0083]
[0084]
[0085] It can be seen from Table 9 that the oxygen content of the three batches of molybdenum alloy plates is not more than 20ppm, the nitrogen content is not more than 20ppm, and the carbon content is not more than 40ppm; it can be seen from Table 10 that the tensile strength of the three batches of molybdenum alloy plates at 20°C is greater than 740MPa, the range of tensile strength is 11MPa, the yield strength is greater than 600MPa, the elongation is not less than 35%, and the range of elongation is 1.7%; it can be seen from Table 11 that the three batches of molybdenum alloy plates The tensile strength of the materials at 1200℃ is greater than 230MPa, the range of tensile strength is 3.9MPa, the yield strength is greater than 130MPa, the elongation is not less than 20%, and the range of elongation is 1.8%; as shown in Table 12, the tensile strength of the three batches of molybdenum alloy plates at 1500℃ is greater than 120MPa, the range of tensile strength is 6.6MPa, the yield strength is greater than 90MPa, the elongation is not less than 25%, and the range of elongation is 1.2%.
[0086] In summary, the oxygen and nitrogen contents of the molybdenum alloy plate prepared in this embodiment are not more than 20 ppm, and the carbon content is not more than 40 ppm; the molybdenum alloy plate prepared in this embodiment has good tensile properties at 20°C, 1200°C, and 1500°C, and the tensile properties are stable.
[0087] Example 4
[0088] The preparation method of this embodiment comprises the following steps:
[0089] Step 1, 5kg of molybdenum particles, 12g of titanium particles, 5g of zirconium particles and 0.3g of carbon particles are mixed evenly and then vacuum suspended smelting is performed 4 times to form a molybdenum alloy ingot; the process of the vacuum suspension smelting is: evacuate the vacuum suspension smelting furnace to a vacuum degree of no more than 0.5Pa, fill it with argon until the argon pressure reaches 10kPa, and perform vacuum suspension smelting after multiple cycles of vacuum evacuation and argon filling. After completion, the obtained smelted ingot is turned 180° in the vertical direction and then placed in the vacuum suspension smelting furnace again for the next vacuum suspension smelting; the power of the vacuum suspension smelting is 275kW, and the time of the vacuum suspension smelting is 10min; the mass purity of the molybdenum particles is 99.95% and the particle size is 4mm, the mass purity of the titanium particles is 99.96% and the particle size is 3mm, the mass purity of the zirconium particles is 99.97% and the particle size is 8mm, and the mass purity of the carbon particles is 99.95% and the particle size is 2mm;
[0090] Step 2: grinding the molybdenum alloy ingot obtained in step 1, cutting off the riser, and coating the ingot with a high-temperature antioxidant, heating it to 1000° C. in a hydrogen atmosphere for 2 hours, and then forging and grinding it to obtain a molybdenum alloy forging blank; the deformation amount of each forging is 6%, and the cumulative deformation amount of the forging is 35%;
[0091] Step 3, the molybdenum alloy forging blank obtained in step 2 is placed in a hydrogen atmosphere, heated to 1000° C., kept warm for 1.5 hours, and then cross-rolled to obtain a rolled plate; the first rolling deformation is 30%, and the cumulative rolling deformation is 90%;
[0092] Step 4: subjecting the rolled plate obtained in step 3 to annealing heat treatment, and then grinding, alkali washing and polishing to obtain a molybdenum alloy plate; the annealing heat treatment is carried out in a hydrogen atmosphere, the annealing heat treatment temperature is 1000°C, and the annealing heat treatment holding time is 2h.
[0093] According to the preparation method of this embodiment, three batches of molybdenum alloy plates were prepared. The oxygen, nitrogen and carbon content of the three batches of molybdenum alloy plates were measured, and the tensile mechanical properties were tested at 20°C, 1200°C and 1500°C. The test results are shown in Tables 13 to 16.
[0094] Table 13 Element contents of 3 batches of molybdenum alloy plates in this embodiment
[0095] batch Oxygen content / ppm Nitrogen content / ppm Carbon content / ppm 1 19 18 37 2 18 18 36 3 19 20 32
[0096] Table 14 20℃ tensile properties of 3 batches of molybdenum alloy plates in this example
[0097] batch Tensile strength / MPa Yield strength / MPa Elongation / % 1 746 630 35.0 2 733 622 36.4 3 741 619 38.0 Very bad 13 / 3.0
[0098] Table 15 1200℃ tensile properties of 3 batches of molybdenum alloy plates in this example
[0099]
[0100]
[0101] Table 16 1500℃ tensile properties of 3 batches of molybdenum alloy plates in this embodiment
[0102] batch Tensile strength / MPa Yield strength / MPa Elongation / % 1 121 91 25.7 2 130 98 25.1 3 123 94 27.9 Very bad 9 / 2.8
[0103] It can be seen from Table 13 that the oxygen content of the three batches of molybdenum alloy plates is not more than 20ppm, the nitrogen content is not more than 20ppm, and the carbon content is not more than 40ppm; it can be seen from Table 14 that the tensile strength of the three batches of molybdenum alloy plates at 20°C is greater than 740MPa, the range of tensile strength is 13MPa, the yield strength is greater than 600MPa, the elongation is not less than 25%, and the range of elongation is 3.0%; it can be seen from Table 15 that the three batches of molybdenum alloy plates have a tensile strength of more than 740MPa at 20°C, the range of tensile strength is 13MPa, the yield strength is greater than 600MPa, the elongation is not less than 25%, and the range of elongation is 3.0%. The tensile strength of the gold plates at 1200°C is greater than 230MPa, the range of tensile strength is 12MPa, the yield strength is greater than 130MPa, the elongation is not less than 20%, and the range of elongation is 2.4%; as can be seen from Table 16, the tensile strength of the three batches of molybdenum alloy plates at 1500°C is greater than 120MPa, the range of tensile strength is 9MPa, the yield strength is greater than 90MPa, the elongation is not less than 25%, and the range of elongation is 2.8%.
[0104] In summary, the oxygen and nitrogen contents of the molybdenum alloy plate prepared in this embodiment are not more than 20 ppm, and the carbon content is not more than 40 ppm; the molybdenum alloy plate prepared in this embodiment has good tensile properties at 20°C, 1200°C, and 1500°C, and the tensile properties are stable.
[0105] Example 5
[0106] The difference between this embodiment and embodiment 4 is that in step 1, the particle size of the molybdenum particles is 5 mm, the particle size of the titanium particles is 8 mm, and the particle size of the carbon particles is 3 mm; in step 4, the annealing heat treatment temperature is 1150° C., and the annealing heat treatment holding time is 1 hour.
[0107] According to the preparation method of this embodiment, three batches of molybdenum alloy plates were prepared. The oxygen, nitrogen and carbon content of the three batches of molybdenum alloy plates were measured, and the tensile mechanical properties were tested at 20°C, 1200°C and 1500°C. The test results are shown in Tables 17 to 20.
[0108] Table 17 Element contents of 3 batches of molybdenum alloy plates in this example
[0109] batch Oxygen content / ppm Nitrogen content / ppm Carbon content / ppm 1 13 12 33 2 15 19 37 3 18 20 27
[0110] Table 18 20℃ tensile properties of 3 batches of molybdenum alloy plates in this example
[0111] batch Tensile strength / MPa Yield strength / MPa Elongation / % 1 765 647 35.7 2 764 652 35.2 3 754 641 37.6 Very bad 11 / 2.4
[0112] Table 19 1200℃ tensile properties of 3 batches of molybdenum alloy plates in this example
[0113] batch Tensile strength / MPa Yield strength / MPa Elongation / % 1 231.9 132.4 20.2 2 241.7 133.1 22.9 3 236.0 136.3 21.7 Very bad 9.8 / 2.7
[0114] Table 20 1500℃ tensile properties of 3 batches of molybdenum alloy plates in this embodiment
[0115] batch Tensile strength / MPa Yield strength / MPa Elongation / % 1 120.4 90.4 25.9 2 128.9 91.6 25.2 3 132.7 90.7 28.2 Very bad 12.3 / 3.0
[0116] It can be seen from Table 17 that the oxygen content of the three batches of molybdenum alloy plates is not more than 20ppm, the nitrogen content is not more than 20ppm, and the carbon content is not more than 40ppm; it can be seen from Table 18 that the tensile strength of the three batches of molybdenum alloy plates at 20°C is greater than 740MPa, the range of tensile strength is 11MPa, the yield strength is greater than 600MPa, the elongation is not less than 35%, and the range of elongation is 2.4%; it can be seen from Table 19 that the three batches of molybdenum alloy plates The tensile strength of the materials at 1200℃ is greater than 230MPa, the range of tensile strength is 9.8MPa, the yield strength is greater than 130MPa, the elongation is not less than 20%, and the range of elongation is 2.7%; as shown in Table 20, the tensile strength of the three batches of molybdenum alloy plates at 1500℃ is greater than 120MPa, the range of tensile strength is 12.3MPa, the yield strength is greater than 90MPa, the elongation is not less than 25%, and the range of elongation is 3.0%.
[0117] In summary, the oxygen and nitrogen contents of the molybdenum alloy plate prepared in this embodiment are not more than 20 ppm, and the carbon content is not more than 40 ppm; the molybdenum alloy plate prepared in this embodiment has good tensile properties at 20°C, 1200°C, and 1500°C, and the tensile properties are stable.
[0118] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural transformation made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.
Claims
1. A method for preparing a high temperature resistant low oxygen molybdenum alloy plate for a fast reactor, characterized in that: The preparation method comprises the following steps: Step 1: Evenly mix molybdenum particles, titanium particles, zirconium particles and carbon particles, and then perform vacuum suspension melting for at least 2 times to form a molybdenum alloy ingot; Step 2: grinding the molybdenum alloy ingot obtained in step 1, removing the riser, and coating the ingot with a high-temperature antioxidant, and then heating and heat-insulating the ingot in a hydrogen atmosphere, forging and grinding the ingot to obtain a molybdenum alloy forging blank; wherein the deformation amount of each forging pass is 5% to 10%; Step 3, placing the molybdenum alloy forging blank obtained in step 2 in a hydrogen atmosphere, heating and heat preservation, and then cross-rolling to obtain a rolled plate; Step 4: The rolled plate obtained in step 3 is subjected to annealing heat treatment, grinding, alkali washing and polishing in sequence to obtain a molybdenum alloy plate.
2. The method for preparing a high temperature resistant low oxygen molybdenum alloy plate for fast reactor according to claim 1, characterized in that: After each completion of the vacuum suspension smelting in step 1, the obtained smelted ingot is turned 180° in the vertical direction and then placed in a vacuum suspension smelting furnace.
3. The method for preparing a high temperature resistant low oxygen molybdenum alloy plate for fast reactor according to claim 1, characterized in that: The process of vacuum suspension melting in step 1 is: evacuate the vacuum suspension melting furnace to a vacuum degree not greater than 0.5Pa, fill it with argon until the argon pressure reaches 10kPa, and perform vacuum suspension melting after repeated cycles of vacuuming and filling with argon; the power of the vacuum suspension melting is 260kW~280kW, and the time of the vacuum suspension melting is 8min~12min.
4. The method for preparing a high temperature resistant low oxygen molybdenum alloy plate for fast reactor according to claim 1, characterized in that: The mass purity of the molybdenum particles in step one is not less than 99.95%, and the particle size of the molybdenum particles is 3mm-5mm; the mass purity of the titanium particles is not less than 99.95%, and the particle size of the titanium particles is 3mm-8mm; the mass purity of the zirconium particles is not less than 99.95%, and the particle size of the zirconium particles is 3mm-8mm; the mass purity of the carbon particles is not less than 99.95%, and the particle size of the carbon particles is 1mm-3mm.
5. The method for preparing a high temperature resistant low oxygen molybdenum alloy plate for fast reactor according to claim 1, characterized in that: The heating temperature in the hydrogen atmosphere in step 2 is 1000° C. to 1200° C., the insulation time in the hydrogen atmosphere is 0.5 h to 2 h, and the cumulative deformation of the forging is 30% to 45%.
6. The method for preparing a high temperature resistant low oxygen molybdenum alloy plate for fast reactor according to claim 1, characterized in that: The heating temperature in the hydrogen atmosphere in step three is 1000° C. to 1200° C., the insulation time in the hydrogen atmosphere is 0.5 h to 2 h, the deformation of the first rolling pass is not less than 20%, and the cumulative deformation of the rolling is 70% to 90%.
7. The method for preparing a high temperature resistant low oxygen molybdenum alloy plate for fast reactor according to claim 1, characterized in that: The annealing heat treatment in step 4 is performed in a hydrogen or argon atmosphere, the temperature of the annealing heat treatment is 1000° C. to 1200° C., and the holding time of the annealing heat treatment is 0.5 h to 2 h.
8. A high temperature resistant low oxygen molybdenum alloy plate for fast reactor prepared by the method according to any one of claims 1 to 7, characterized in that: The molybdenum alloy plate has an oxygen content of no more than 20 ppm, a nitrogen content of no more than 20 ppm, and a carbon content of no more than 40 ppm.
9. The high temperature resistant low oxygen molybdenum alloy plate for fast reactor according to claim 8, characterized in that: The tensile strength of the molybdenum alloy plate at 20°C is not less than 740MPa, the yield strength is not less than 600MPa, and the elongation is not less than 35%; the tensile strength of the molybdenum alloy plate at 1200°C is not less than 230MPa, the yield strength is not less than 130MPa, and the elongation is not less than 20%; the tensile strength of the molybdenum alloy plate at 1500°C is not less than 120MPa, the yield strength is not less than 90MPa, and the elongation is not less than 25%.
10. The high temperature resistant low oxygen molybdenum alloy plate for fast reactor according to claim 9, characterized in that: The extreme difference in tensile strength of the molybdenum alloy plates of the same batch at 20° C., 1200° C. and 1500° C. is no more than 15 MPa, and the extreme difference in elongation is no more than 3%.