CN1252309C - Heat treatment method for improving high-niobium reinforcing type monocrystal high temp alloy use property - Google Patents
Heat treatment method for improving high-niobium reinforcing type monocrystal high temp alloy use property Download PDFInfo
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- CN1252309C CN1252309C CN 02144627 CN02144627A CN1252309C CN 1252309 C CN1252309 C CN 1252309C CN 02144627 CN02144627 CN 02144627 CN 02144627 A CN02144627 A CN 02144627A CN 1252309 C CN1252309 C CN 1252309C
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- 229910045601 alloy Inorganic materials 0.000 title claims abstract description 64
- 239000000956 alloy Substances 0.000 title claims abstract description 64
- 239000010955 niobium Substances 0.000 title claims abstract description 30
- 229910052758 niobium Inorganic materials 0.000 title claims abstract description 26
- 238000000034 method Methods 0.000 title claims abstract description 16
- 230000003014 reinforcing effect Effects 0.000 title abstract 5
- 238000010438 heat treatment Methods 0.000 title description 2
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 claims abstract description 22
- 230000032683 aging Effects 0.000 claims abstract description 17
- 238000001816 cooling Methods 0.000 claims abstract description 16
- 238000005204 segregation Methods 0.000 claims abstract description 15
- 238000000265 homogenisation Methods 0.000 claims abstract description 9
- 229910000601 superalloy Inorganic materials 0.000 claims description 16
- 239000013078 crystal Substances 0.000 claims description 12
- 238000001556 precipitation Methods 0.000 claims description 5
- 238000010276 construction Methods 0.000 claims description 2
- 238000005266 casting Methods 0.000 abstract description 17
- 238000012545 processing Methods 0.000 abstract description 10
- 238000000465 moulding Methods 0.000 abstract description 2
- 238000003672 processing method Methods 0.000 abstract 1
- 238000007669 thermal treatment Methods 0.000 description 13
- 238000009413 insulation Methods 0.000 description 12
- 230000000694 effects Effects 0.000 description 9
- 238000005728 strengthening Methods 0.000 description 9
- 238000012360 testing method Methods 0.000 description 6
- 238000001513 hot isostatic pressing Methods 0.000 description 5
- 239000000463 material Substances 0.000 description 4
- 229910000851 Alloy steel Inorganic materials 0.000 description 3
- 229910000905 alloy phase Inorganic materials 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 229910001068 laves phase Inorganic materials 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 210000001787 dendrite Anatomy 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000002203 pretreatment Methods 0.000 description 2
- 238000007712 rapid solidification Methods 0.000 description 2
- 238000002791 soaking Methods 0.000 description 2
- 238000010792 warming Methods 0.000 description 2
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 230000002939 deleterious effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 229910001119 inconels 625 Inorganic materials 0.000 description 1
- 229910000816 inconels 718 Inorganic materials 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 230000035882 stress Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
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- Crystals, And After-Treatments Of Crystals (AREA)
- Turbine Rotor Nozzle Sealing (AREA)
Abstract
The present invention discloses a thermal processing method for improving the use performance of high-niobium reinforcing type monocrystal high-temperature alloy. A homogenization and ageing thermal processing technique is made according to the noncrystal boundary characteristics of monocrystal alloy and the inherent structure characteristics of high-niobium reinforcing type alloy. Operation can be carried out according to the following procedures: 1), high-temperature homogenization processing is carried out by that samples are put in environments with the temperature of 1140 DEG C to 1170 DEG C, heat is preserved for 5 to 30 hours, harmful phases are eliminated, and niobium segregation and cooling are carried out; 2), reinforcing phases are separated out by conventional aging processing to obtain products. The present invention can largely improve the strength of high-niobium reinforcing type high-temperature alloy castings and improve the plasticity to a certain degree, and meanwhile, the characteristics of few connection points, easy molding and short processing periods of cast alloy are reserved. Thereby, the service performance of the alloy is obviously improved.
Description
Technical field
The present invention relates to a kind of heat treating method that improves high niobium intensified type single crystal super alloy use properties.
Background technology
Superalloy is to make Aeronautics and Astronautics, marine engine, and the critical material of heat power plant's internal combustion turbine.With the aircraft engine is example, improves air inlet temperature, increases thrust-weight ratio, alleviates engine weight, and the security of raising engine use and weather resistance etc., is the key of improving level of engine performance.And realize that these purposes directly depend on the production and the use of the superalloy with good tissue and performance.In miscellaneous superalloy, be that the superalloy of main strengthening element occupies an important position with niobium.This class alloy can be separated out a large amount of and higher the γ " (Ni of matrix coherency stress
3Nb) phase, strengthening effect is remarkable, thereby has the higher characteristics of intensity (document 1:M.K hler, U.Heuber, The effect of final heat treatment and chemical composition onsensitization, strength and thermal stability of alloy 625.in ' Superalloys 718,625,706 and Various Derivatives ', ed.by E.A.Loria, TMS, 1997, p.795.; Document 2: Dong Jianxin, the development of INCONEL718 superalloy, the Arms Material scientific and engineering, in March, 1996, the 19th volume, the 2nd phase, P.46).But because content of niobium is higher, the segregation tendency of alloy is serious, is easy to separate out the Laves phase, deals with improperly, will influence the use properties of alloy.
As the representative of high niobium intensified type superalloy, the IN718 alloy can use under as cast condition and deformation states.With deformation states IN718 alloy phase ratio, the intensity of casting IN718 alloy is lower, but can avoid because the low intensity points that welding or various connection bring also has the alternate of being difficult to advantage for unmanageable shaped piece.Various trials have now been carried out to improve the use properties of IN718 alloy-steel casting, as the grain structure of method refinement casting IN718 alloy that adopts rapid solidification to be improving the intensity and the toughness of alloy, thereby but rapid solidification causes producing in the alloy-steel casting a large amount of cavities that the use properties of alloy is produced deleterious effect.In order to eliminate the cavity blemish that these produce in castingprocesses, adopted hot isostatic pressing technique to handle to alloy-steel casting, though hip treatment can make the cavity closed, but casting polycrystalline IN718 alloy generally need keep some Laves as the grain-boundary strengthening phase, therefore can not thoroughly eliminate dendrite and do and interdendritic component segregation.In addition, the Nb content of Laves phase is higher, keeps a part of Laves and must reduce γ " Ni mutually
3The content of Nb strengthening phase.Therefore the intensity potentiality of casting the IN718 alloy can't be given full play to.Other high niobium intensified type alloy, as about all about 3.5wt.% of the content of niobium of Inconel 625 and Inconel725 alloy, the segregation tendency is also all very serious.Therefore, solidifying segregation how to eliminate high niobium intensified type alloy is a key of giving full play to this alloy property potentiality.
Summary of the invention
In order to overcome above-mentioned deficiency, the purpose of this invention is to provide a kind of can keep the casting alloy tie point few and be easy to shaping characteristic in, thoroughly eliminate its mutually harmful and niobium segregation, precipitation strength phase to greatest extent makes the heat treating method of the high niobium intensified type of the more excellent improvement of its strengthening effect single crystal super alloy use properties.
To achieve these goals, technical scheme of the present invention is: do not have the characteristics and the high niobium intensified type alloy inherent weave construction characteristics of crystal boundary at single crystal alloy, formulate homogenizing and aging thermal treating process, can operate as follows:
1) high-temperature homogenization is handled: sample is inserted under 1140~1170 ℃ of temperature environments, be incubated 5~30 hours, eliminate harmful niobium segregation that reaches mutually, cooling;
2) conventional ageing treatment precipitation strength phase promptly gets product;
In addition, employing the present invention can be according to the concrete size situation of test specimen before described ageing treatment, add high-temperature homogenization and handle subordinate phase, that is: improve treatment temp once more, be controlled between 1180~1240 ℃, soaking time generally is controlled between 5~50 hours according to particular cases such as test specimen sizes.
The present invention is used for high niobium intensified type superalloy with single crystal technology, eliminated the crystal boundary of alloy, thereby can fully eliminate interdendritic component segregation, reached maximum strengthening effect by thermal treatment, and keep casting alloy and reduce tie point and be easy to characteristics such as moulding, on technology a kind of innovation.Its advantage specifically is:
1. use properties is more excellent.Through the monocrystalline IN718 alloy that the present invention handles, thoroughly eliminate its mutually harmful and niobium segregation, its intensity reaches with the casting polycrystalline alloy with plasticity index to be compared, and not only intensity increases substantially, and plasticity also increases substantially; With distortion IN718 alloy phase ratio, can reach distortion IN718 alloy level.
2. simple, cycle weak point.The inventive method can be saved and forge or manufacturing procedure such as rolling, has shortened the production cycle.
3. have the advantage of casting and deforming alloy concurrently.The advantage that the inventive method has kept casting alloy need not be multi-link excessively, be suitable for making unmanageable shaped piece, and its performance reaches the level of deforming alloy, expanded the use range of alloy, provide to make and under middle temperature limiting condition, to have used and to have the approach of good over-all properties material.
Embodiment
Below in conjunction with specific embodiment in detail the present invention is described in detail.
The processing of 1 couple of monocrystalline IN718 of embodiment alloy
A kind of homogenizing and the timeliness heat treating regime that the present invention is directed to high niobium intensified type superalloy are: getting monocrystalline as cast condition IN718 alloy is sample 1, is incubated 20 hours down at 1160 ℃, eliminates harmful phase Laves and reaches the niobium segregation mutually, and alloy melting point rises to 1240 ℃.And then alloy is warming up to 1240 ℃, be incubated 20 hours, air cooling (homogenizing processing); 720 ℃ the insulation 8 hours, 50 ℃ per hour the cooling rate stove be chilled to 620 ℃, 620 ℃ the insulation 8 hours, air cooling (ageing treatment).
The sample that other gets same material and size adopts conventional heat treating regime (J.T.Guo, L.Z.Zhou, The effect of phosphorus, sulfur and silicon, on segregation, solidificationand mechanical properties in cast alloy 718.in ' Superalloys 1996 ', eds.By R.D.kissinger et al., TMS, 1996, p.451) handle: 1090 ℃ are incubated 1 hour, air cooling (homogenizing processing); 950 ℃ are incubated 1 hour, air cooling (solution treatment); 720 ℃ the insulation 8 hours, 50 ℃ per hour the cooling rate stove be chilled to 620 ℃, 620 ℃ the insulation 8 hours, air cooling (ageing treatment).
After adopting above-mentioned two kinds of heat treating regimes to handle respectively to monocrystalline IN718 alloy, measure mechanical property and compared.The measurement result of its room temperature tensile performance is as shown in table 1, compare with heat treating regime commonly used, adopt special thermal treatment system of the present invention to handle, monocrystalline IN718 alloy at room temperature tensile strength has obtained significantly to improve, yield strength has improved 178MPa, breaking tenacity has improved 411MPa, and plasticity also has some improvement.
Table 1 heat treating regime is to monocrystalline IN718 alloy room temperature tensile Effect on Performance
Heat treating regime | Yield strength σ 0.2(Mpa) | Breaking tenacity σ b(MPa) | Unit elongation δ (%) | Reduction of area ψ (%) |
Adopt thermal treatment commonly used | 909 | 972 | 16 | 24 |
Adopt the present invention | 1087 | 1383 | 18 | 34.5 |
The enduring quality measurement result is as shown in table 2, compares with heat treating regime commonly used, adopts special thermal treatment system of the present invention to handle, and the enduring quality of monocrystalline IN718 alloy has obtained improvement equally, and rupture life slightly increases, and fracture plasticity increases considerably.
Table 2 heat treating regime is to 650 ℃ of monocrystalline IN718 alloys, the influence of 720MPa enduring quality
Heat treating regime | Life-span, τ (hour) | Elongation, δ (%) | Reduction of area, ψ (%) |
Adopt thermal treatment commonly used | 95 | 35.60 | 27.75 |
Adopt the present invention | 121.26 | 43.2 | 60.82 |
The processing of 2 pairs of IN718 alloys of embodiment
Getting monocrystalline as cast condition IN718 alloy is test specimen 2, handles through high-temperature homogenization earlier, and promptly 1145 ℃ are incubated 25 hours, eliminates harmful phase Laves and reaches the niobium segregation mutually, and alloy melting point rises to 1240 ℃.And then alloy is warming up to 1200 ℃, be incubated 30 hours, air cooling; Carry out conventional ageing treatment precipitation strength phase then, promptly 720 ℃ the insulation 8 hours, with 50 ℃ per hour the average rate stove be chilled to 620 ℃, 620 ℃ the insulation 8 hours, air cooling.
Adopt the thermal treatment of prior art hot isostatic pressing that as cast condition polycrystalline IN718 alloy is handled: through hot isostatic pressing: 1121 ℃, 102.9MPa pressure is incubated 3 hours.Then 1065 ℃ of insulations 1 hour, 718 ℃ are incubated 8 hours, with 50 ℃ per hour the average rate stove be chilled to 621 ℃, and (data are drawn from document: Patty Siereveld to be incubated 8 hours at 621 ℃, John F.Radavich, Tom Kelly, Gail Cole, Robert Widmer, Effect of HIP Parameters on Fine Grain Cast Alloy 718, in ' Superalloys 1988 ', eds.by S.Reichman, D.N.Duhl, G.Maurer, S.Antolovich, and C.Lund, The Metallurgical Society, 1988.p.459).Adopt the present invention to handle test specimen 2 and see Table 3 with the heat treated result of prior art hot isostatic pressing.
The influence of table 3 different treatment method IN718 alloy at room temperature tensile property and heat treating regime
Working method | Thermal treatment | Breaking tenacity σ b(MPa) | Yield strength σ s(MPa) | Elongation δ (%) | Reduction of area ψ (%) |
The casting polycrystalline | Hot isostatic pressing thermal treatment | 1162 | 1011 | 12.1 | 17.9 |
Monocrystalline | The present invention | 1379 | 1085 | 19 | 35.4 |
As shown in table 3, eliminate harmful phase by thermal treatment, and dendrite is done and interdendritic composition uniformity." strengthening phase reaches best strengthening effect farthest to separate out equally distributed γ by ageing treatment then.Owing to can eliminate component segregation up hill and dale, through the single crystal alloy that heat treating method of the present invention is handled, compare with the as cast condition polycrystalline alloy, not only intensity increases substantially (yield strength has improved 217Mpa, and breaking tenacity has improved 74MPa), and plasticity also increases substantially.
The processing of 3 pairs of K718 alloys of embodiment
Selecting (monocrystalline) K718 alloy for use is test specimen 3, and difference from Example 1 is that homogenizing is treated to a stage:
1. high-temperature homogenization is handled:
Sample is inserted under 1170 ℃ of temperature environments, eliminate harmful phase and improve alloy melting point, be incubated 50 hours Laves phased solns, and eliminate the Nb segregation to test specimen;
2. conventional ageing treatment precipitation strength phase:
Ageing treatment adopts the standard system of ageing treatment of high niobium intensified type alloy: 720 ℃ of down insulations 8 hours, 2 hours at the uniform velocity stove be chilled to 620 ℃, 620 ℃ of insulations 8 hours down, air cooling.
In addition, adopt polycrystalline cast conventional thermal treatment (Zhao Jingchen, Wang Bin, Sun Jiahua, homogenization temperature be to K718 alloy structure and Effect on Performance, the 6th national superalloy annual meeting, p.273): adopt 1090 ℃ respectively, 1170 ℃, 1200 ℃ of insulations pre-treatment in 4 hours; 970 ℃ are incubated 1 hour, air cooling then; 720 ℃ the insulation 8 hours, 50 ℃ per hour the cooling rate stove be chilled to 620 ℃, 620 ℃ the insulation 8h, air cooling (ageing treatment).After conventional thermal treatment, though its pre-treatment can be clean with Laves phase basically eliminate, may be because crystal boundary lacks strengthening phase, the intensity of alloy still is difficult to the monocrystalline IN718 alloy phase ratio through the present invention's processing, and its room temperature tensile performance is as shown in table 4.
Table 4 polycrystalline casting K718 and monocrystalline IN718 alloy room temperature tensile performance are relatively
Alloy and heat treating regime | Yield strength σ 0.2(Mpa) | Breaking tenacity σ b(Mpa) | Unit elongation δ (%) | Reduction of area ψ (%) |
Polycrystalline casting K718 (employing thermal treatment) | 882.9 | 1030 | 14.7 | 20.4 |
Monocrystalline IN718 (employing the present invention) | 1072 | 1377 | 17 | 32.3 |
As seen, adopt special thermal treatment system of the present invention to handle, K718 alloy at room temperature tensile strength has obtained significantly to improve, and yield strength has improved 189.1MPa, and breaking tenacity has improved 347MPa, and plasticity also has some improvement.
In addition, the present invention also can reconcile aging temp and soaking time according to specific requirement.
Claims (1)
1. heat treating method that improves high niobium intensified type single crystal super alloy use properties, it is characterized in that: characteristics and the high niobium intensified type alloy inherent weave construction characteristics of not having crystal boundary at single crystal alloy, formulate homogenizing and aging thermal treating process, as follows operation:
1) high-temperature homogenization is handled: sample is inserted under 1140~1170 ℃ of temperature environments, be incubated 5~30 hours, eliminate harmful niobium segregation that reaches mutually, cooling;
2) conventional ageing treatment precipitation strength phase promptly gets product;
Wherein before described ageing treatment, add high-temperature homogenization and handle subordinate phase, that is: improve treatment temp once more, be controlled between 1180~1240 ℃, be incubated 5~50 hours.
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CN107523772B (en) * | 2016-06-22 | 2019-06-11 | 中国科学院金属研究所 | A kind of homogenization process of U720Li high temperature alloy |
CN106198605A (en) * | 2016-08-04 | 2016-12-07 | 中国科学院金属研究所 | The method of evaluating performance of single crystal super alloy under a kind of special environment |
CN106756695A (en) * | 2017-02-24 | 2017-05-31 | 西北工业大学 | Improve the Technology for Heating Processing that β solidifies Nb TiAl alloys fragility in water vapour environment high |
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