ZA200106731B - Method for making thin zirconium alloy elements and wafers obtained. - Google Patents
Method for making thin zirconium alloy elements and wafers obtained. Download PDFInfo
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- ZA200106731B ZA200106731B ZA200106731A ZA200106731A ZA200106731B ZA 200106731 B ZA200106731 B ZA 200106731B ZA 200106731 A ZA200106731 A ZA 200106731A ZA 200106731 A ZA200106731 A ZA 200106731A ZA 200106731 B ZA200106731 B ZA 200106731B
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- South Africa
- Prior art keywords
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- carried out
- cold
- rolling
- temperature below
- Prior art date
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- 238000000034 method Methods 0.000 title claims description 33
- 229910001093 Zr alloy Inorganic materials 0.000 title description 6
- 235000012431 wafers Nutrition 0.000 title 1
- 238000000137 annealing Methods 0.000 claims description 32
- 230000008569 process Effects 0.000 claims description 27
- 238000005097 cold rolling Methods 0.000 claims description 21
- 238000010438 heat treatment Methods 0.000 claims description 20
- 229910045601 alloy Inorganic materials 0.000 claims description 15
- 239000000956 alloy Substances 0.000 claims description 15
- 238000005096 rolling process Methods 0.000 claims description 13
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 12
- 238000011282 treatment Methods 0.000 claims description 12
- 238000004519 manufacturing process Methods 0.000 claims description 10
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 7
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 7
- 238000005098 hot rolling Methods 0.000 claims description 7
- 229910052760 oxygen Inorganic materials 0.000 claims description 7
- 239000001301 oxygen Substances 0.000 claims description 7
- 229910052717 sulfur Inorganic materials 0.000 claims description 7
- 239000011593 sulfur Substances 0.000 claims description 7
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 claims description 6
- 229910052742 iron Inorganic materials 0.000 claims description 6
- 238000001953 recrystallisation Methods 0.000 claims description 6
- 229910052726 zirconium Inorganic materials 0.000 claims description 6
- 239000011651 chromium Substances 0.000 claims description 5
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims description 4
- 229910052804 chromium Inorganic materials 0.000 claims description 4
- 239000012535 impurity Substances 0.000 claims description 4
- 229910052758 niobium Inorganic materials 0.000 claims description 4
- 239000010955 niobium Substances 0.000 claims description 4
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 claims description 4
- 239000003758 nuclear fuel Substances 0.000 claims description 4
- 229910052718 tin Inorganic materials 0.000 claims description 4
- 229910052720 vanadium Inorganic materials 0.000 claims description 4
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 3
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 claims description 3
- 238000005253 cladding Methods 0.000 description 5
- 239000012736 aqueous medium Substances 0.000 description 3
- 238000005520 cutting process Methods 0.000 description 3
- 239000002244 precipitate Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 239000000460 chlorine Substances 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 238000007689 inspection Methods 0.000 description 2
- 239000011777 magnesium Substances 0.000 description 2
- 239000011572 manganese Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 238000005554 pickling Methods 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 239000011734 sodium Substances 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 229910052770 Uranium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052793 cadmium Inorganic materials 0.000 description 1
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 239000002826 coolant Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000012634 fragment Substances 0.000 description 1
- 229910052735 hafnium Inorganic materials 0.000 description 1
- VBJZVLUMGGDVMO-UHFFFAOYSA-N hafnium atom Chemical compound [Hf] VBJZVLUMGGDVMO-UHFFFAOYSA-N 0.000 description 1
- 238000004845 hydriding Methods 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000002609 medium Substances 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 125000006850 spacer group Chemical group 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- JFALSRSLKYAFGM-UHFFFAOYSA-N uranium(0) Chemical compound [U] JFALSRSLKYAFGM-UHFFFAOYSA-N 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C3/00—Reactor fuel elements and their assemblies; Selection of substances for use as reactor fuel elements
- G21C3/02—Fuel elements
- G21C3/04—Constructional details
- G21C3/06—Casings; Jackets
- G21C3/07—Casings; Jackets characterised by their material, e.g. alloys
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Metallurgy (AREA)
- Plasma & Fusion (AREA)
- General Engineering & Computer Science (AREA)
- High Energy & Nuclear Physics (AREA)
- Heat Treatment Of Steel (AREA)
- Heat Treatment Of Sheet Steel (AREA)
- Metal Rolling (AREA)
Description
PN WO 00/48199 PCT/FR00/00357
PROCESS FOR MANUFACTURING THIN COMPONENTS MADE OF A
ZIRCONIUM-BASED ALLOY AND STRAPS THUS PRODUCED
The invention relates to processes for manufacturing thin components made of a zirconium-based alloy which are intended to be used in water-cooled nuclear reactors and especially, among these, in pressurized- water reactors.
One particularly important application of the invention is in the manufacture of sheets intended to be cut so as to form structural components of the backbone of a nuclear fuel assembly and especially to form spacer grid straps for the fuel rods.
Such structural components are required to have, simultaneously, good resistance to the coolant, consisting of a high-temperature aqueous medium, low free growth in the direction of the large dimension of the component, and reduced creep in the «case of components subjected to stresses. In addition, the manufacturing process must not result in a high scrap rate.
The aim of the invention is especially to provide a process allowing these objectives to be achieved, especially by avoiding the presence of the PBZr phase which has an unfavorable effect from the oxidation standpoint. The aim of the invention is also, secondarily, to provide a process employing a zirconium-based alloy that can also be used to form cladding tubes, which are in contact not only with the aqueous medium but also with the fuel.
Tubes have already been proposed (EP-A-0 720 177) which are made of a zirconium-based alloy also containing 50 to 250 ppm iron, 0.8 to 1.3 wt% niobium, less than 1600 ppm oxygen, less than 200 ppm carbon and less than
- 2 = ® 120 ppm silicon. Such an alloy is drawn and then cold- rolled in at least four passes (the term “rolling” denoting, in the case of tube, passage over a mandrel against which the blank is pressed by forming rolls), in several passes, with intermediate heat treatments between 560°C and 620°C.
At these relatively low temperatures, advantageous from the standpoint of corrosion resistance, recrystallization of the alloy, necessary for the next rolling pass to be carried out properly, requires a long time.
A process according to the invention makes it possible to produce flat thin structural components by a process that can be employed on a continuous line. According to this process, a blank made of a zirconium-based alloy is formed, said alloy also containing, by weight, beside the inevitable impurities, 0.8 to 1.3% niobium, 500 to 2000 ppm oxygen and 5 to 35 ppm sulfur and, ~ optionally, Fe, Cr and V with a total content of less than 0.25% and tin with a content of less than 300 ppm.
A blank, resulting from a PB hardening operation and a hot-rolling pass, is rolled in at least three cold- rolling passes with intermediate annealing heat treatments, one of these intermediate heat treatments or a prior heat treatment before the first cold-rolling pass being carried out for a long time, of at least 2 hours, at a temperature below 600°C, and all the optional heat treatments which follow the long treatment being carried out at a temperature generally between 610 and 620°C for at most 15 min, in general 2 to 10 min.
Often 1100 to 1800 ppm oxygen and 10 to 35 ppm sulfur will be used.
® hs
One advantage of “short” treatments of at most 15 min is that they can be carried out in continuous furnaces.
However, they may be at a temperature causing the BZr phase to appear, since this phase will be eliminated by the “long” treatment.
In a first method of implementation, the number of cold-rolling passes is only three. The first intermediate heat treatment is at a temperature exceeding 620°C, causing the PZr phase to appear, and of short duration, compatible with the use of continuous furnaces. On the other hand, the treatment which immediately precedes the final rolling is at a low temperature, below 600°C, and of a duration exceeding 2 hours, which can be carried out in a bell furnace. This operation eliminates practically all the
Bzr phase. A treatment below 560°C is especially possible, with a duration which then exceeds 5 hours.
In a second method of implementation, four cold-rolling passes are carried out with short intermediate annealing operations between the first two or first three passes at a temperature resulting in the appearance of the pZr phase. The PBZr phase is then eliminated by a long annealing operation (more than 2 hours) at a temperature below 600°C before the final or penultimate rolling, depending on the case. An annealing operation of more than 5 hours below 560°C allows a similar result to be achieved.
In yet another case, the process comprises four (or more) cold-rolling passes and the treatment of long duration at a temperature below 600°C (often below 560°C) is carried out immediately after hot rolling.
All the subsequent annealing operations are below 620°C, short (less than 15 min) and carried out in a continuous furnace.
In all «cases, a final recrystallization annealing operation is carried out at a temperature low enough to prevent the PZr phase from appearing, that is to say below 620°C.
The thin component thus obtained constitutes a sheet which no longer undergoes thermometallurgical treatment before use, but simply planishing, pickling, inspection and, finally, cutting operations.
The manufacture may be carried out with continuous annealing furnaces for all the short heat treatments at high temperature. The annealing operation to eliminate the PZr phase requires only a time of several hours, typically 5 to 15 h, between 520 and 580°C, for example in a bell furnace.
All of the heat treatments are carried out in an inert atmosphere or under vacuum.
The presence of sulfur with a low content improves the hot creep in an aqueous medium. An oxygen content of between 1000 and 1600 ppm is advantageous. It may be adjusted by a deliberate and controlled addition of zirconium.
The alloy used also lends itself to the formation of claddings, by a process involving several rolling passes in a pilger rolling mill, this time with long intermediate heat treatments at a temperature low enough not to make the PZr phase appear.
The same alloy containing 5 to 35 ppm (especially 10 to 35 ppm) sulfur consequently makes it possible to form, from ingots of the same composition, both flat
® ST components cut from a sheet and cladding tubes or nuclear fuel assembly guide tubes.
The above characteristics, together with others, will
Dbecome more clearly apparent on reading the description which follows of particular methods of implementation, these being given by way of nonlimiting examples. The description refers to the drawings which accompany it, in which: - figures 1 to 3 are flowcharts for the manufacture of sheet intended for nuclear-fuel assembly grid straps: - figure 4 shows schematically a fragment of a grid strap that can be produced according to the invention.
The process, the steps of which are illustrated in the figures, was used to form sheets from 0.4 mm to 0.6 mm in thickness, intended to form, by cutting and press- drawing, grid straps having openings for housing a spring, of the kind shown for example in figure 4.
However, the springs may be formed by drawn parts of the straps.
The manufacturing process firstly comprises the casting of an ingot having the required composition.
Heterogeneities result in some «cases in an ingot, portions of which, especially the ends and sometimes the peripheral parts, have a content which lies outside the permitted ranges. In this case, the corresponding parts are removed by cutting.
The products studied form particular examples, for which a niobium content of between 1.01 and 1.03%, a sulfur content of between 15 and 28 ppm and an oxygen content of 1280 to 1390 ppm was obtained. For all the other elements present as impurities, the contents were
® less than the following values: (ppm) (ppm)
Aluminum Al 75 Manganese Mn 50
Boron B 0.5 Molybdenum Mo 50
Cadmium Cd 0.5 Nickel Ni 70
Calcium Ca 30 Nitrogen N 80
Carbon Cc 100 Phosphorus P 20
Chlorine Cl 20 Silicon Si 120
Chromium Cr 150 Sodium Na 20
Cobalt Co 10 Tantalum Ta 100
Copper Cu 50 Tin Sn 100
Hafnium Hf 100 Titanium Ti 50
Hydrogen H 25 Tungsten Ww 100
Iron Fe 500 Uranium (total) U 3.5
Lead Pb 130 Vanadium \ 50
Magnesium Mg 20
Starting from an ingot, a thick sheet bar was manufactured, by rolling, the thickness of which was 100 mm in the case studied. A rolling pass 10 carried out hot, generally between 930 and 960°C, brought this sheet bar to a thickness of 30 mm. After rolling, the product underwent a PB hardening operation 12, generally from a temperature of between 1000°C and 1200°C, giving a blank. The blank then underwent a new hot-rolling pass 14, typically between 770 and 790°C.
All these operations are common to all the methods of implementing the invention.
Example 1 (figure 1)
In this case, three cold-rolling passes were carried out. The hot-rolling pass 14 was followed by two first
® cold-rolling passes 16; and 16, between which an annealing operation 18; was carried out in a continuous annealing furnace which allowed only a temperature soak for a time not exceeding 15 min, generally about two to ten minutes. This required a high temperature, of between 690°C and 710°C - that is to say above the o/a,3 transition temperature. Going to “these high temperatures results in the appearance of BZr phases, which must subsequently be eliminated almost completely in order to improve the oxidation resistance of the sheet.
The annealing operation 18; was carried out at about 700°C for a time of around 4 min.
On the other hand, the annealing operation 20 to eliminate the PBZr phase was carried out in a bell furnace for 10 to 12 hours, off line, at a nominal temperature of 550°C.
The final cold-rolling pass 163 was followed by a recrystallization annealing operation 24 carried out below 620°C in order not to make the PZr phase appear in a significant amount. In practice, this annealing operation may be carried out in a continuous furnace, by a soak for two to ten minutes at 610°C to 620°C.
The sheet obtained as a result of the annealing operation 24 was used without any further heat treatment. It was subjected to the usual pickling and inspection operations, then cut and drawn in order to form therein springs, if necessary, or to place therein attached springs made of. another material, such as a nickel-based alloy.
® Example 2 (figure 2)
The process of example 2 comprises four cold rolling- passes. It was used to form sheets 0.425 to 0.6 mm in thickness.
For both the desired thicknesses, four cold-rolling passes 16g, 163, 16, and 163 were carried out. The intermediate continuous annealing operations 18; and 18; were carried out at 700°C. But this time, the long heat treatment 26 at low temperature (below 560°C) preceded the last two cold-rolling passes 16; and 163. The heat treatment 18, was below 620°C, for example at a nominal temperature of 610°C, for a few minutes. The final recrystallization annealing operation 24 may also have been carried out at 615°C for a few minutes, in a continuous furnace.
All the operations indicated at A in figure 2 are the same for the two desired final thicknesses. The following cold-rolling passes were carried out with suitable deformation ratios.
In a variant, it is the cold-rolling pass 16; which is followed by the annealing operation intended to eliminate the PZr phase almost completely. To do this, the annealing operation is carried out below 620°C.
Annealing for 5 to 15 hours, at 520°C to 580°C, gives good results.
The above process is capable of variants. The number of cold-rolling passes may be increased. The annealing operation 26 to eliminate the [Zr phase may be carried out at a lower temperature provided the duration is longer.
Example 3 (figure 3)
In yet another method of implementation, four cold- rolling passes were provided. However, the low- temperature annealing operation 28 of long duration, to eliminate the PZr phase, preceded the cold-rolling passes. In this case, the following temperatures were especially used (the references being those of figure 3): :
Hot rolling pass 14: 770 ~ 790°C
Long annealing 28 to eliminate PZr: 550°C (below the phase change temperature) for 10 to 12 hours
Continuous annealing - operations 18qy, 181, 185: 610°C at a speed of 0.6 to 1 m/min, resulting in a duration of about 3 to 4 min.
Annealing 24: 615°C, for a few minutes, in a continuous furnace.
The sheets obtained by the process according to the invention were subjected to metallurgical examinations and to tests.
The intermetallic precipitates were finely and uniformly distributed. Electron microscope examinations : showed a few alignments of PNb precipitates due to the annealing operations 18. In contrast, the BzZr precipitates were present as traces and were isolated.
- 10 pu. ® The measured Kearns factors for the 0.425 mm thick sheet were 0.09 in the longitudinal rolling direction, 0.23 in the transverse direction and 0.68 in the normal direction: they were very comparable to those of recrystallized Zircaloy 4. Tests were carried out to determine the uniform corrosion under irradiation.
The maximum thickness of oxide formed for a burn-up rate of 62 GWd/t remained less than 27 um, lower than on guide tubes made of recrystallized Zircaloy 4 and on a sheet made of stress-relieved Zircaloy-4.
The free growth of the sheets manufactured by the process, measured at 350°C, was very close to that of
Zircaloy 4 up to a fluence of about 6x10%°n/cm®. Above this value, a saturation phenomenon was observed, such that the free growth was roughly half that of Zircaloy 4 for a fluence of 25x10%°n/cm?.
The improvement in hydriding over Zircaloy 4 was also very significant, since the absorbed hydrogen factor was reduced by almost a half.
When it is desired to use the same alloy to manufacture claddings and straps, it is advantageous to incorporate into the alloy 0.03 to 0.25% iron in total, on the one hand, and at least one of chromium and of vanadium on the other hand. The Fe/ (Cr+V) ratio is then advantageously at least 0.5. It may also be useful to add tin to improve the strength of the claddings in a lithium-containing medium.
It will be seen that it is possible to place the long heat treatment at various steps in the manufacturing cycle, with the sole condition that no subsequent treatment be provided at a temperature liable to make the BZr phase appear.
Claims (13)
1. Process for manufacturing flat thin components, in which a blank made of a zirconium-based alloy is formed, said alloy also containing, by weight, besides the inevitable impurities, 0.8 to 1.3% niobium, 500 to 2000 ppm oxygen and 5 to 35 ppm sulfur and, optionally, up to 0.25% Fe+Cr+V and up to 300 ppm tin; a B hardening operation and a hot- rolling pass are carried out in order to obtain a ~ blank and the blank is rolled in at least three cold-rolling passes with intermediate annealing heat treatments, one of these intermediate heat treatments or a prior heat treatment before the first cold-rolling pass being carried out for a long time, of at least 2 hours, at a temperature below 600°C and all the optional heat treatments which follow the long treatment being carried out at a temperature below 620°C for at most 15 min.
2. Process according to claim 1, characterized in that the number of cold-rolling passes is three, the first heat treatment being at a temperature + exceeding 620°C and of short duration, whereas the treatment which immediately precedes the final rolling pass is at a temperature below 600°C and has a duration exceeding 2 hours.
3. Process according to claim 2, characterized in that the first heat treatment is carried out at a temperature of between 690°C and 710°C in less than 15 min.
4. Process according to claim 1, characterized in that four cold-rolling passes are carried out with short intermediate annealing operations before the
- 12 ~ ® first two or three cold-rolling passes, at a temperature exceeding 620°C, resulting in the appearance of the pZr phase, then the long annealing operation for more than 2 hours at a temperature below 600°C before the final rolling pass or the penultimate one depending on the case.
5. Process according to claim 1, characterized in that it includes at least four cold-rolling passes and the treatment of long duration at a temperature below 600°C is carried out immediately after the hot rolling.
6. Process according to any of the preceding claims, characterized by a final recrystallization annealing operation at a temperature below 620°C, low enough not to make the BZr phase appear.
7. Process according to claim 6, characterized in that the final recrystallization annealing is carried out between 610°C and 620°C for 2 to 10 min.
8. Process according to any one of the preceding claims, characterized in that the short annealing operations are «carried out in a continuous furnace.
9. Process according to any one of the preceding claims, characterized in that the alloy contains 1100 to 1800 ppm oxygen and 10 to 35 ppm sulfur.
10. Process according to any one of the preceding claims, characterized in that one of the heat treatments is carried out for a long time, of at least 5 hours, at a temperature below 560°C.
®
11. Process according to any one of the preceding claims, characterized in that the treatment which immediately precedes the final rolling pass is at a temperature below 560°C and for a time exceeding 5 hours.
12. Process according to any one of the preceding claims, characterized in that iron, chromium, vanadium and tin are present only in the state of impurities.
13. Thin nuclear-fuel assembly grid strap cut and drawn into a thin component manufactured by the process according to any one of claims 1 to 12.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR9901777A FR2789795B1 (en) | 1999-02-15 | 1999-02-15 | PROCESS FOR THE MANUFACTURE OF ZIRCONIUM-BASED ALLOY THIN ELEMENTS AND INSERTS THUS PRODUCED |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| ZA200106731B true ZA200106731B (en) | 2002-10-15 |
Family
ID=9542008
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| ZA200106731A ZA200106731B (en) | 1999-02-15 | 2001-08-15 | Method for making thin zirconium alloy elements and wafers obtained. |
Country Status (2)
| Country | Link |
|---|---|
| FR (1) | FR2789795B1 (en) |
| ZA (1) | ZA200106731B (en) |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5925963A (en) * | 1982-08-02 | 1984-02-10 | Sumitomo Metal Ind Ltd | Manufacture of hot rolled ti alloy plate |
| FR2575764B1 (en) * | 1985-01-10 | 1992-04-30 | Cezus Co Europ Zirconium | PROCESS FOR MANUFACTURING A STRIP OF ZIRCONIUM ALLOY ZIRCALOY 2 OR ZIRCALOY 4 RESTORED, AND STRIP OBTAINED |
| FR2599049B1 (en) * | 1986-05-21 | 1988-07-01 | Cezus Co Europ Zirconium | PROCESS FOR THE MANUFACTURE OF A ZIRCALOY 2 OR ZIRCALOY 4 SHEET PARTIALLY RECRYSTALLIZED AND SHEET OBTAINED |
| FR2624136B1 (en) * | 1987-12-07 | 1992-06-05 | Cezus Co Europ Zirconium | TUBE, BAR OR SHEET IN ZIRCONIUM ALLOY, RESISTANT TO BOTH UNIFORM CORROSION AND NODULAR CORROSION AND METHOD OF MANUFACTURE THEREOF |
| JP2548773B2 (en) * | 1988-06-06 | 1996-10-30 | 三菱重工業株式会社 | Zirconium-based alloy and method for producing the same |
| FR2729000A1 (en) * | 1994-12-29 | 1996-07-05 | Framatome Sa | METHOD OF MANUFACTURING A TUBE FOR ASSEMBLY OF NUCLEAR FUEL AND TUBES CONFORMING TO THOSE OBTAINED |
-
1999
- 1999-02-15 FR FR9901777A patent/FR2789795B1/en not_active Expired - Fee Related
-
2001
- 2001-08-15 ZA ZA200106731A patent/ZA200106731B/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| FR2789795A1 (en) | 2000-08-18 |
| FR2789795B1 (en) | 2001-05-25 |
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