GH907 alloy bar and preparation method and application thereof
Through uniform diffusion annealing and multi-fire forging processes on GH907 alloy self-consumed ingots, the problems of uneven structure and inconsistent performance of GH907 alloy rods were solved, and GH907 alloy rods that meet the standard requirements were prepared, with wide application prospects.
Patent Information
- Application Number
- CN202411753979.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-02
- Publication Date
- 2025-03-07
AI Technical Summary
During mass production, the existing GH907 alloy rods have uneven tissues, resulting in excessive clutter in material flaw detection or poor performance, which makes it difficult to meet the standard requirements.
After uniform diffusion annealing of GH907 alloy self-consumed ingots, a multi-fire forging process is adopted to control the forging temperature, fire, deformation amount and heat treatment system, and GH907 alloy rods with uniform grain size, stable quality, flaw detection and all performance indicators are prepared.
It has achieved improvement in the structure uniformity and performance of GH907 alloy rods, met the standard requirements of level 4, and has the prospect of widespread promotion and application.
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Abstract
Description
Technical Field
[0001] The invention relates to the technical field of alloy manufacturing, and in particular to a GH907 alloy bar and a preparation method and application thereof. Background Art
[0002] GH907 alloy has high strength, low thermal expansion coefficient, good thermal fatigue performance and almost constant elastic modulus below 650℃. In recent years, low expansion GH907 alloy has been widely used as important casing components of aircraft engines in China. GH907 alloy has a complex structure, which is composed of γ matrix, γ' phase, ε phase, ε'' phase, Laves phase, MC carbide and G phase precipitation phases. The main phases include γ' phase, ε phase and MC carbide.
[0003] The comprehensive performance, composition, uniformity of structure and quality stability of materials are important prerequisites for mass production in the metallurgical industry. Due to the difficulty in controlling the uniformity of the alloy structure, the GH907 alloy produced by the existing process in my country often has problems such as uneven structure due to mismatch between strain and material temperature during mass production, resulting in excessive noise in material flaw detection or incompatible performance. Therefore, it is imperative to seek a preparation method for GH907 alloy bars with uniform structure, qualified flaw detection and performance. Summary of the invention
[0004] In view of the above technical problems, the present invention provides a GH907 alloy bar and a preparation method and application thereof. The GH907 alloy bar prepared by the preparation method can overcome the shortcomings of the prior art such as uneven alloy structure, non-compliant flaw detection or non-compliant performance, and other properties also meet the standard requirements. The GH907 alloy bar prepared by the present invention can be used to prepare GH907 alloy after aging heat treatment, which can be further used in the preparation of components in aerospace engines.
[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a method for preparing a GH907 alloy bar, the preparation method comprising the following steps: The GH907 alloy consumable ingot is subjected to homogenization diffusion annealing and then forged to obtain GH907 alloy rods; The heating temperature of the forging is 1120°C to 970°C, and the number of fires is 5; Among them, the heating temperature of the 1st to 3rd fire is 1100℃~1120℃, and the deformation of each fire is 25%~35%; The heating temperature for the 4th to 5th fires is 970℃~990℃, and the deformation of each fire is 40%~50%.
[0006] The present invention studies the deformation process of the forging process, and provides a GH907 alloy consumable ingot which is obtained by controlling the forging temperature, the number of fires, the deformation amount and the heat treatment system after diffusion, so as to obtain a GH907 alloy bar with uniform grain size, stable quality, and qualified flaw detection and various performance indicators.
[0007] The present invention finds that the temperature and deformation of two fires are particularly important for preparing GH907 alloy bars. In the present invention, the heating temperature of the 4th to 5th fires is controlled to be 970℃~990℃, and the axial elongation deformation is performed, and the deformation of each fire is 40%~50%; by moderate deformation at a relatively low temperature, larger distortion can help obtain fine grain structure. The alloy grain size of the GH907 alloy bar obtained within the scope of this application is 5.0-6.0, which meets the standard requirements of finer than 4, and the flaw detection and other properties also meet the standard requirements.
[0008] The preparation method of the GH907 alloy rod provided by the present invention does not need to introduce other equipment on the basis of existing metallurgical equipment, has the prospect of wide promotion and application, and is of great significance to promoting the preparation of low expansion high temperature alloys in my country.
[0009] Preferably, the heat preservation time of each of the 1st to 3rd firings is 2h to 4h.
[0010] Preferably, the first and second fires are both axial upsetting deformations; and the third fire is axial drawing deformation.
[0011] Preferably, the 4th to 5th fires are all axial stretching deformations, and the insulation time for each fire is 0.8h to 1.2h.
[0012] Preferably, the homogenization diffusion annealing includes keeping the temperature at 1150°C-1170°C for 38h-42h, then heating to 1180°C-1200°C for 2h-4h and keeping the temperature for 68h-72h. The specific diffusion annealing process is: The GH907 alloy consumable ingot is charged into the furnace at a temperature lower than 700°C, kept at 690°C-710°C for 1h-2h, then uniformly heated to 990°C-1010°C in 8h-10h and kept warm for 2h, uniformly heated to 1150°C-1170°C in 4h-6h and kept warm for 40h, then heated to 1180°C-1200°C in 2h-4h and kept warm for 70h, cooled to 600°C in the furnace and then taken out of the furnace for air cooling.
[0013] The reason for setting the above diffusion annealing process is that the low-melting-point phase between dendrites in the GH907 alloy consumable ingot is the Laves phase. The present invention has found in experiments that the optimal dissolution temperature of the intergranular Laves phase in the GH907 alloy consumable ingot is about 1160°C, and the Laves phase can be completely eliminated after diffusing for more than 10 hours. During production, the optimal diffusion effect of the niobium element is taken into consideration, and the diffusion time at 1150°C~1170°C is finally controlled to be about 40 hours. First, the low-melting-point phase can be completely dissolved back to avoid overheating caused by further heating; second, the diffusion rate of the niobium element can be fully improved to achieve the optimal effect. When the low-melting-point Laves phase is completely dissolved back, in order to improve its diffusion efficiency, the temperature is raised to 1190±10°C and kept for about 70 hours to complete the optimal diffusion process.
[0014] Preferably, the method for preparing the GH907 alloy consumable ingot comprises: vacuum induction melting and vacuum casting of the GH907 alloy material to obtain a vacuum induction electrode; The vacuum induction electrode is subjected to a vacuum consumable remelting to obtain a GH907 alloy consumable ingot.
[0015] Further preferably, the chemical composition of the vacuum induction electrode is: C≤0.06wt%, Ni 35.0wt%~40.0wt%, Cr<0.10wt%, Co 13.0wt%~15.0wt%, Al<0.05wt%, Ti 1.55wt%~1.70wt%, Nb+Ta4.75wt%~5.15wt%, Mn≤0.60wt%, P≤0.015wt%, Cu<0.1wt%, Mo<0.1wt%, B≤0.012wt%, Si0.23wt%~0.35wt%, S≤0.002%, O≤0.0015wt%, N≤0.004wt%, and the balance is Fe and unavoidable impurities.
[0016] In the present invention, by analyzing and strictly controlling the chemical composition in the vacuum induction electrode, the quality of the obtained GH907 alloy rod can be more stable and the performance can be more excellent.
[0017] In a second aspect, the present invention provides a GH907 alloy rod, which is prepared by the preparation method of the GH907 alloy rod provided in the first aspect.
[0018] The GH907 alloy bar provided by the present invention has uniform structure, the alloy grain size meets the standard requirement of finer than grade 4, and the high temperature tensile performance, notch endurance performance and flaw detection indicators all meet the relevant provisions of "HB 7682-2000 Low Expansion GH907 Alloy Ring Blanks and Ring Parts". The GH907 alloy bar provided by the present invention has excellent performance, stable quality and market competitiveness.
[0019] In a third aspect, the GH907 alloy rod provided by the present invention can be used to prepare GH907 alloy after aging heat treatment, and the GH907 alloy can be further used in the preparation of components in aerospace engines. DETAILED DESCRIPTION
[0020] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0021] Example 1 This embodiment provides a method for preparing a GH907 alloy bar, and the preparation method comprises the following steps: Step 1: Place the GH907 alloy material in a vacuum induction furnace for vacuum induction melting, vacuum pouring, mold cooling for 2 hours, stress de-annealing, and obtain a Φ430mm vacuum induction electrode. The chemical composition of the vacuum induction electrode is analyzed, and the analysis results are as follows: C 0.025wt%, Ni 38.2wt%, Cr 0.04wt%, Co 13.2wt%, Al 0.02wt%, Ti 1.6wt%, Nb+Ta 4.82wt%, Mn 0.2wt%, P 0.006wt%, Cu 0.03wt%, Mo 0.03wt%, B 0.005wt%, Si 0.26wt%, S0.001%, O 0.0006wt%, N 0.0015wt%, and the balance is Fe and unavoidable impurities.
[0022] Step 2: After flattening and polishing the vacuum induction electrode, place it in a vacuum consumable furnace, control the steady-state melting rate to 3.3-3.5 kg / min, and the droplet rate to 5 l / s, perform a vacuum consumable remelting, and cool it in the furnace for 1 hour after power failure to obtain a GH907 alloy consumable ingot of Φ508 mm; Step 3, the above GH907 alloy consumable ingot is polished and subjected to homogenization diffusion annealing. The annealing process is as follows: loading the furnace at 600°C and keeping it at 700°C for 1h, then uniformly heating it to 1000°C in 8h and keeping it for 2h, then heating it to 1160°C in 4h and keeping it for 40h, then uniformly heating it to 1190°C in 3h and keeping it for 70h, cooling the furnace to 600°C and then taking it out of the furnace for air cooling to obtain the diffused GH907 alloy consumable ingot; Step 4, forging the above-mentioned diffused GH907 alloy consumable ingot to obtain GH907 alloy rods. This embodiment is illustrated by taking the preparation of Φ250mm rods as an example. In order to ensure a sufficient forging ratio, the internal structure of the rod is fully broken. The hot-processed rods are forged by multiple fires, and the production process of two upsetting + multiple drawing is carried out. The insulation time for the 1st to 3rd fires is 3h, and the insulation time for the 4th to 5th fires is 1h; the specific forging temperature, deformation amount and deformation mode are shown in Table 1 below.
[0023] Table 1
[0024] After testing, the obtained GH907 alloy rod has a uniform grain size of 5.0~6.0, which meets the standard requirement of finer than 4.
[0025] Example 2 This embodiment provides a method for preparing a GH907 alloy bar, and the preparation method comprises the following steps: Step 1: Place the GH907 alloy material in a vacuum induction furnace for vacuum induction melting, vacuum pouring, mold cooling for 2 hours, stress de-annealing, and obtain a Φ430mm vacuum induction electrode. The chemical composition of the vacuum induction electrode is analyzed, and the analysis results are as follows: C 0.04wt%, Ni 37.1wt%, Cr 0.03wt%, Co 15.0wt%, Al 0.01wt%, Ti 1.7wt%, Nb+Ta5.13wt%, Mn 0.3wt%, P 0.005wt%, Cu 0.02wt%, Mo 0.03wt%, B 0.004wt%, Si 0.35wt%, S0.001%, O 0.0005wt%, N 0.002wt%, and the balance is Fe and unavoidable impurities.
[0026] Step 2: After flattening and polishing the vacuum induction electrode, place it in a vacuum consumable furnace, control the steady-state melting rate to 3.3-3.5 kg / min, and the droplet rate to 5 l / s, perform a vacuum consumable remelting, and cool it in the furnace for 1 hour after power failure to obtain a GH907 alloy consumable ingot of Φ508 mm; Step 3, the above GH907 alloy consumable ingot is polished and subjected to homogenization diffusion annealing. The annealing process is as follows: loading the furnace at 650°C and keeping it at 690°C for 2h, then uniformly heating to 1010°C in 10h and keeping it for 2h, then heating to 1160°C in 5h and keeping it for 42h, then uniformly heating to 1200°C in 3h and keeping it for 68h, cooling the furnace to 600°C and then taking it out of the furnace for air cooling to obtain the diffused GH907 alloy consumable ingot; Step 4: Forge the above-mentioned diffused GH907 alloy consumable ingot to obtain GH907 alloy rods. This embodiment is described by taking the preparation of Φ250mm rods as an example. The hot-processed rods are forged by multiple fires, and the production process of two upsettings + multiple stretchings is carried out. The holding time of the 1st to 3rd fires is 4h, and the holding time of the 4th to 5th fires is 1.2h. The specific forging temperature, deformation amount and deformation mode are shown in Table 2 below.
[0027] Table 2
[0028] After testing, the obtained GH907 alloy rod has a uniform grain size of 5.0~6.0, which meets the standard requirement of finer than 4.
[0029] Example 3 This embodiment provides a method for preparing a GH907 alloy bar, and the preparation method comprises the following steps: Step 1: Place the GH907 alloy material in a vacuum induction furnace for vacuum induction melting, vacuum pouring, mold cooling for 2 hours, stress de-annealing, and obtain a Φ430mm vacuum induction electrode. The chemical composition of the vacuum induction electrode is analyzed, and the analysis results are as follows: C 0.025wt%, Ni 38.2wt%, Cr 0.04wt%, Co 13.2wt%, Al 0.02wt%, Ti 1.6wt%, Nb+Ta 4.82wt%, Mn 0.2wt%, P 0.006wt%, Cu 0.03wt%, Mo 0.03wt%, B 0.005wt%, Si 0.26wt%, S0.001%, O 0.0006wt%, N 0.0015wt%, and the balance is Fe and unavoidable impurities.
[0030] Step 2: After flattening and polishing the vacuum induction electrode, place it in a vacuum consumable furnace, control the steady-state melting rate to 3.3-3.5 kg / min, and the droplet rate to 5 l / s, perform a vacuum consumable remelting, and cool it in the furnace for 1 hour after power failure to obtain a GH907 alloy consumable ingot of Φ508 mm; Step 3, the above GH907 alloy consumable ingot is polished and subjected to homogenization diffusion annealing. The annealing process is as follows: loading the furnace at 650°C and keeping it at 700°C for 1h, then uniformly heating it to 1000°C in 8h and keeping it for 2h, then heating it to 1160°C in 4h and keeping it for 40h, then uniformly heating it to 1180°C in 3h and keeping it for 72h, cooling the furnace to 600°C and then taking it out of the furnace for air cooling to obtain the diffused GH907 alloy consumable ingot; Step 4. Forge the above-mentioned diffused GH907 alloy consumable ingot to obtain GH907 alloy rods. This embodiment is illustrated by taking the preparation of Φ250mm rods as an example. In order to ensure a sufficient forging ratio, the internal structure of the rod is fully broken. The hot-processed rods are forged by multiple fires, and undergo two upsetting + multiple drawing production processes. Among them, the insulation time for the 1st to 3rd fires is 2h, and the insulation time for the 4th to 5th fires is 0.8h; the specific forging temperature, deformation amount and deformation mode are shown in Table 3 below.
[0031] Table 3
[0032] After testing, the obtained GH907 alloy rod has a uniform grain size of 5.0~6.0, which meets the standard requirement of finer than 4.
[0033] Comparative Example 1 This comparative example provides a method for preparing a GH907 alloy bar, which is basically the same as that of Example 1, except that the forging process in step 4 is different, and the other raw materials and preparation parameters are the same. The forging process of this comparative example is shown in Table 4 below.
[0034] Table 4 Fire temperature Deformation Deformation method 1 1110℃ 30% Upsetting + drawing 2 1110℃ 30% Upsetting + drawing 3 1110℃ 30% Pull out 4 1110℃ 45% Pull out 5 1110℃ 45% Pull out After testing, the grain size of the GH907 alloy rod obtained in this comparative example is a mixed crystal structure of 7.0 to 3.0 levels, especially the elongated grains in the surface layer reach 2.0 level, which cannot meet the standard requirement of finer than 4 levels.
[0035] Comparative Example 2 This comparative example provides a method for preparing a GH907 alloy bar, which is basically the same as that of Example 1, except that the forging process in step 4 is different, and the other raw materials and preparation parameters are the same. The forging process of this comparative example is shown in Table 5 below.
[0036] Table 5 Fire temperature Deformation Deformation method 1 1110℃ 30% Upsetting + drawing 2 1110℃ 30% Upsetting + drawing 3 1110℃ 30% Pull out 4 980℃ 25% Pull out 5 980℃ 25% Pull out 6 980℃ 25% Pull out After testing, the grain size of the GH907 alloy rod obtained in this comparative example is a mixed crystal structure of 5.0 to 2.0 levels, which cannot meet the standard requirement of finer than 4 levels.
[0037] Comparative Example 3 This comparative example provides a method for preparing a GH907 alloy bar, which is basically the same as Example 1, except that the forging process in step 4 is different, and the other raw materials and preparation parameters are the same. The forging process of this comparative example is shown in Table 6 below. Because the specification of the consumable ingot before forging is Φ508mm ingot, and the finished product specification is Φ250mm, in order to achieve the target specification of forging, the fire number of this comparative example is 6 fires, otherwise it cannot be forged to the target specification. If 6 fires are set in the following comparative examples, it is also for this reason.
[0038] Table 6 Fire temperature Deformation Deformation method 1 1110℃ 30% Upsetting + drawing 2 1110℃ 30% Upsetting + drawing 3 1110℃ 30% Pull out 4 1110℃ 25% Pull out 5 1110℃ 25% Pull out 6 1110℃ 25% Pull out After testing, the grain size of the GH907 alloy rod obtained in this comparative example is 3.0~5.0 level, which does not meet the standard requirement of being finer than 4 level.
[0039] Comparative Example 4 This comparative example provides a method for preparing a GH907 alloy bar, which is basically the same as that of Example 1, except that the forging process in step 4 is different, and the other raw materials and preparation parameters are the same. The forging process of this comparative example is shown in Table 7 below.
[0040] Table 7 Fire temperature Deformation Deformation method 1 1150℃ 30% Upsetting + drawing 2 1150℃ 30% Upsetting + drawing 3 1150℃ 30% Pull out 4 1020℃ 30% Pull out 5 1020℃ 20% Pull out 6 1020℃ 20% Pull out After testing, the grain size of the GH907 alloy rod obtained in this comparative example is 1.5~3.0 level, which does not meet the standard requirement of being finer than level 4.
[0041] Comparative Example 5 This comparative example provides a method for preparing a GH907 alloy bar, which is basically the same as that of Example 1, except that the forging process in step 4 is different, and the other raw materials and preparation parameters are the same. The forging process of this comparative example is shown in Table 8 below.
[0042] Table 8 Fire temperature Deformation Deformation method 1 1150℃ 30% Upsetting + drawing 2 1150℃ 30% Upsetting + drawing 3 1150℃ 30% Pull out 4 1020℃ 45% Pull out 5 1020℃ 45% Pull out After testing, the grain size of the GH907 alloy rod obtained in this comparative example is 3.5~5.5 levels, which does not meet the standard requirement of being finer than level 4.
[0043] Comparative Example 6 This comparative example provides a method for preparing a GH907 alloy bar, which is basically the same as that of Example 1, except that the forging process in step 4 is different, and the other raw materials and preparation parameters are the same. The forging process of this comparative example is shown in Table 9 below.
[0044] Table 9 Fire temperature Deformation Deformation method 1 1050℃ 30% Upsetting + drawing 2 1050℃ 30% Upsetting + drawing 3 1050℃ 30% Pull out 4 960℃ 25% Pull out 5 960℃ 25% Pull out 6 960℃ 25% Pull out The results show that the grain size of the GH907 alloy rod obtained in this comparative example is a mixed crystal of level 0-6.0, which cannot meet the standard requirement of being finer than level 4.
[0045] Comparative Example 7 This comparative example provides a method for preparing a GH907 alloy bar, which is basically the same as that of Example 1, except that the forging process in step 4 is different, and the other raw materials and preparation parameters are the same. The forging process of this comparative example is shown in Table 10 below.
[0046] Table 10 Fire temperature Deformation Deformation method 1 1050℃ 30% Upsetting + drawing 2 1050℃ 30% Upsetting + drawing 3 1050℃ 30% Pull out 4 960℃ 45% Pull out 5 960℃ 45% Pull out The results show that the grain size of the GH907 alloy rod obtained in this comparative example is 3.0-7.0 mixed crystal, which cannot meet the standard requirement of being finer than 4 grades.
[0047] Effect example The physical and chemical properties of the GH907 alloy bars prepared in Examples 1 to 3 and Comparative Examples 1 to 7 were measured, and the specific results are shown in Table 11 below.
[0048] Table 11
[0049] Ultrasonic testing was performed on the GH907 alloy bars prepared in Examples 1 to 3 and Comparative Examples 1 to 7 to examine their flaw detection results. The specific flaw detection results are shown in Table 12 below.
[0050] Table 12
[0051] In summary, the products prepared by the preparation methods of GH907 alloy bars provided in Examples 1 to 3 of the present invention have a grain size that meets the requirements, a more uniform structure, better stability, and other properties that meet the standard requirements, while the products prepared in Comparative Examples 1 to 7 cannot ensure that all indicators meet the standard requirements. In view of the quality and performance advantages of the GH907 alloy bars provided by the present invention, they can be used to prepare fasteners with high temperature resistance, for example, the preparation of related components in aerospace.
[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims
1. A method for preparing GH907 alloy rod, characterized in that: The preparation method comprises the following steps: The GH907 alloy consumable ingot is subjected to homogenization diffusion annealing and then forged to obtain GH907 alloy rods; The heating temperature of the forging is 1120°C to 970°C, and the number of fires is 5; Among them, the heating temperature of the 1st to 3rd fire is 1100℃~1120℃, and the deformation of each fire is 25%~35%; The heating temperature for the 4th to 5th fires is 970℃~990℃, and the deformation of each fire is 40%~50%.
2. The method for preparing the GH907 alloy bar according to claim 1, characterized in that: The heat preservation time of each of the 1st to 3rd fires is 2h~4h.
3. The method for preparing the GH907 alloy bar according to claim 1 or 2, characterized in that: The first and second fires are both axial upsetting deformation; and / or The third fire is axial stretching deformation.
4. The method for preparing the GH907 alloy bar according to claim 1, characterized in that: The fourth and fifth fires are all axial elongation deformation; and / or For the 4th to 5th fire, the insulation time for each fire is 0.8h~1.2h.
5. The method for preparing the GH907 alloy bar according to claim 1, characterized in that: The homogenization diffusion annealing includes keeping the temperature at 1150°C-1170°C for 38h-42h, then heating to 1180°C-1200°C for 2h-4h and keeping the temperature for 68h-72h.
6. The method for preparing the GH907 alloy bar according to claim 1, characterized in that: The preparation method of the GH907 alloy consumable ingot comprises: subjecting the GH907 alloy material to vacuum induction melting and vacuum casting to obtain a vacuum induction electrode; The vacuum induction electrode is subjected to a vacuum consumable remelting to obtain a GH907 alloy consumable ingot.
7. The method for preparing the GH907 alloy rod according to claim 6, characterized in that: The chemical composition of the vacuum induction electrode is: C≤0.06wt%, Ni 35.0wt%~40.0wt%, Cr<0.10wt%, Co 13.0wt%~15.0wt%, Al<0.05wt%, Ti 1.55wt%~1.70wt%, Nb+Ta 4.75wt%~5.15wt%, Mn≤0.60wt%, P≤0.015wt%, Cu<0.1wt%, Mo<0.1wt%, B≤0.012wt%, Si 0.23wt%~0.35wt%, S≤0.002%, O≤0.0015wt%, N≤0.004wt%, and the balance is Fe and unavoidable impurities.
8. A GH907 alloy bar, characterized in that: The GH907 alloy bar is prepared by the preparation method of any one of claims 1 to 7.
9. Use of the GH907 alloy rod according to claim 8 in aerospace engines.