Preparation method of high-flaw-detection-level titanium alloy cake part based on free forging
By combining free forging with heating and annealing, the problem of uneven microstructure in the production of titanium alloy discs was solved, achieving high-level flaw detection and high-quality titanium alloy disc production.
Patent Information
- Application Number
- CN202510962410.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-14
- Publication Date
- 2025-11-28
AI Technical Summary
Existing titanium alloy disc production methods suffer from poor hardenability, resulting in uneven microstructure and difficulty in achieving high levels of flaw detection. Furthermore, existing production methods are prone to cracking and fracture.
The free forging method is adopted, which combines axial elongation and unidirectional upsetting, and involves multiple reversing elongation and upsetting. Through heating and annealing, the uniform deformation and microstructure of the forging are ensured. The specific steps include chamfering, heating, elongation, upsetting, rounding and heat treatment.
This method achieves high levels of flaw detection and uniform microstructure in titanium alloy discs, improving processing efficiency and product quality while avoiding microstructural defects and cracks.
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Abstract
Description
TECHNICAL FIELD
[0001] The application relates to the field of forging technology, in particular to a high-detection-level titanium alloy pie piece preparation method based on free forging. BACKGROUND
[0002] With the progress of the aviation industry, the aviation engine material develops in the direction of 'light and heat-resistant', since the TC11 alloy has low density and good high-temperature performance, can maintain stable performance at a high temperature, and is widely used in the parts such as the compressor disc, blade and fan wheel disc of the aviation engine.
[0003] However, the poor thermal conductivity of the titanium alloy leads to poor hardenability, thereby limiting the production of thick or large TC11 pie-shaped forgings, and the existing titanium alloy pie pieces are usually produced in the upsetting mode, which is more likely to cause the problems of uneven organization of the titanium alloy forging and difficult standard reaching of the titanium alloy forging detection level. SUMMARY
[0004] In order to solve the above problems, the application provides a high-detection-level titanium alloy pie piece preparation method based on free forging.
[0005] The technical scheme of the application is as follows: a high-detection-level titanium alloy pie piece preparation method based on free forging, comprising the following steps:
[0006] S1, blanking
[0007] The two end faces of the titanium alloy bar are chamfered to obtain a blank;
[0008] S2, free forging
[0009] Step 1: the blank is once elongated and upset along the axial direction to obtain a square blank, and then once elongated and upset along the length direction of the square blank cross section;
[0010] Step 2: the square blank is once elongated and upset along the length direction of the square blank cross section, and then once elongated and upset along the width direction of the square blank cross section;
[0011] Step 3: the square blank is once elongated and upset along the width direction of the square blank cross section, and then once elongated along the axial direction, and then upset along the axial direction, and then rounded and planed, to obtain a forging;
[0012] The blank is heated once before each elongation and upsetting operation, and the heating temperature is 35-55 DEG C below the beta phase transition point;
[0013] S3, heat treatment
[0014] The forging is once annealed and twice annealed to obtain a titanium alloy pie piece.
[0015] Description: The above method ensures uniform deformation of the forging by axial elongation, and further crushes defects such as dendritic crystals and segregation in the center of the blank by the same direction upsetting, and further ensures uniform microstructure of the titanium alloy cake after forging by multiple reversing elongation and upsetting to achieve high flaw detection level.
[0016] Further, in step S1, the chamfer is R15-R20.
[0017] Description: The chamfer can disperse local stress and avoid cracks or fractures caused by stress concentration during subsequent forging or heat treatment.
[0018] Further, in step S2,
[0019] When the blank temperature is ≥850℃, the heating time is 0.4-0.6Lmin each time;
[0020] When the blank temperature is <40℃, the heating time is 240-260min.
[0021] When the blank temperature is <40℃, the heating time is 240-260min.
[0022] Wherein, L is the current length of the blank.
[0023] Description: The change of the holding time with the current length of the blank can make the blank be heated sufficiently, ensure recrystallization of the blank, reduce the grain size difference, eliminate dislocation accumulation, reduce the deformation resistance of the blank, and improve the subsequent processing efficiency.
[0024] Further, in step S2, the length deformation of the blank in the elongation and upsetting steps is 35-50%.
[0025] Description: Limiting the deformation of the blank can avoid instability of metal flow caused by too large single deformation, and avoid cracks in the center of the blank.
[0026] Further, in step S2, the blank is cooled to room temperature by air cooling after the completion of step 1 and step 2, and the blank is cooled to room temperature by water cooling after the completion of step 3.
[0027] Description: Air cooling in step 1 and step 2 can prevent mixed crystal structure caused by too large grain size difference, which can cause defects in the microstructure of the blank during subsequent processing, and water cooling in step 3 can freeze the high-temperature β phase quickly to prevent excessive grain growth during cooling.
[0028] Further, in step S3, the primary annealing method is: heating the forged piece to 45-55 DEG C at the beta transus point, holding for 0.5-1.5 h, then increasing the temperature by 10-20 DEG C, continuing to hold for 220-240 min, and then air cooling.
[0029] Description: The primary annealing can eliminate the forging residual stress, promote the full recrystallization, and reduce the organizational defects of the forged piece.
[0030] Further, in step S3, the secondary annealing method is: heating the forged piece to 520-540 DEG C, holding for 5-7 h, and then air cooling.
[0031] Description: The secondary annealing can fully decompose the metastable beta phase remaining after high-temperature annealing, avoid the precipitation of brittle omega phase or coarse alpha lamella in the subsequent aging process, and ensure the performance of the titanium alloy cake piece.
[0032] The beneficial effects of the present application are:
[0033] (1) The present application can ensure the uniform deformation of the forged piece by axial elongation, and further break the dendritic crystal and segregation defects in the center of the blank by the same direction upsetting, and ensure the uniform organization of the titanium alloy cake piece after forging to achieve the high detection level.
[0034] (2) The holding time of the present application changes with the current length of the blank, which can fully heat the blank, ensure the recrystallization of the blank, reduce the grain size difference, eliminate the dislocation accumulation, reduce the deformation resistance of the blank, and improve the subsequent processing efficiency. DETAILED DESCRIPTION
[0035] In order to further illustrate the manner of carrying out the present application and the effects achieved by it, the technical solutions of the present application will be clearly and completely described below with reference to experiments.
[0036] Embodiment 1: A high-detection-level titanium alloy cake piece preparation method based on free forging, comprising the following steps:
[0037] S1, blanking
[0038] The chamfering is performed on the two end faces of the titanium alloy bar to obtain a blank, wherein the titanium alloy bar is TC11, the diameter is 300 mm, the length is 258 mm, the beta transus point is 1010 DEG C, and the chamfering is R18.
[0039] S2, free forging
[0040] Step 1: elongating and upsetting the blank along the axial direction to obtain a square blank, and then elongating and upsetting the square blank along the length direction of the cross section of the square blank;
[0041] Step 2: once elongation and upsetting along the length direction of the square cross section of the blank, and then once elongation and upsetting along the width direction of the square cross section of the blank;
[0042] Step 3: once elongation and upsetting along the width direction of the square cross section of the blank, and then once elongation along the axial direction of the blank, and then upsetting, rounding and flat end face along the axial direction of the blank to obtain the forged piece;
[0043] After the completion of Step 1 and Step 2, the blank is cooled to room temperature by air cooling, and after the completion of Step 3, the blank is cooled to room temperature by water cooling;
[0044] Before each elongation and upsetting operation, the blank is heated once, and the heating temperature is 45℃ below the beta phase transition point;
[0045] When the blank temperature is ≥ 850℃, the heating time is 0.5Lmin;
[0046] When the blank temperature is < 850℃, the heating time is 0.8Lmin;
[0047] When the blank temperature is < 40℃, the heating time is 250min;
[0048] Wherein, L is the current length of the blank;
[0049] The size change of the blank during the free forging process is as follows:
[0050]
[0051]
[0052] S3, heat treatment
[0053] The forged piece is once annealed and twice annealed to obtain a titanium alloy pie piece;
[0054] The once annealing method is: the forged piece is heated to 50℃ below the beta phase transition point, and kept for 1h, then heated by 15℃, and kept for 230min, and then air cooled;
[0055] The twice annealing method is: the forged piece is heated to 530℃, and kept for 6h, and then air cooled.
[0056] Example 2: this example is basically the same as example 1, except that the chamfer is R15.
[0057] Example 3: this example is basically the same as example 1, except that the chamfer is R20.
[0058] Example 4: This example is basically the same as Example 1, except that the billet is heated once before each elongation and upsetting operation, and the heating temperature is 35°C below the β transus point.
[0059] Example 5: This example is basically the same as Example 1, except that the billet is heated once before each elongation and upsetting operation, and the heating temperature is 55°C below the β transus point.
[0060] Example 6: This example is basically the same as Example 1, except that,
[0061] if the billet temperature is ≥ 850°C, the heating time is 0.4 Lmin;
[0062] if the billet temperature is < 850°C, the heating time is 0.7 Lmin;
[0063] if the billet temperature is < 35°C, the heating time is 240 min.
[0064] Example 7: This example is basically the same as Example 1, except that,
[0065] if the billet temperature is ≥ 850°C, the heating time is 0.6 Lmin;
[0066] if the billet temperature is < 850°C, the heating time is 0.9 Lmin;
[0067] if the billet temperature is < 35°C, the heating time is 260 min.
[0068] Example 8: This example is basically the same as Example 1, except that the single annealing method is to heat the forged piece at 45°C below the β transus point for 1 h, then increase the temperature by 10°C, continue to heat for 230 min, and then air cool.
[0069] Example 9: This example is basically the same as Example 1, except that the single annealing method is to heat the forged piece at 55°C below the β transus point for 1 h, then increase the temperature by 20°C, continue to heat for 230 min, and then air cool.
[0070] Example 10: This example is basically the same as Example 1, except that the single annealing method is to heat the forged piece at 50°C below the β transus point for 0.5 h, then increase the temperature by 15°C, continue to heat for 220 min, and then air cool.
[0071] Example 11: This example is basically the same as Example 1, except that the single annealing method is to heat the forged piece at 50°C below the β transus point for 1.5 h, then increase the temperature by 15°C, continue to heat for 240 min, and then air cool.
[0072] Example 12: This example is basically the same as Example 1, except that the secondary annealing method is to heat the forged piece to 520 DEG C, keep for 5h and then air cool.
[0073] Example 13: This example is basically the same as Example 1, except that the secondary annealing method is to heat the forged piece to 540 DEG C, keep for 7h and then air cool.
[0074] Example 14: This example is basically the same as Example 1, except that the secondary annealing method is to heat the forged piece to 530 DEG C, keep for 5h and then air cool.
[0075] Example 15: This example is basically the same as Example 1, except that the secondary annealing method is to heat the forged piece to 530 DEG C, keep for 7h and then air cool.
[0076] Comparative Example 1: With reference to Example 1, the titanium alloy bar is not chamfered.
[0077] Comparative Example 2: With reference to Example 1, the lengthening and upsetting are always performed in the axial direction during the free forging process.
[0078] Comparative Example 3: With reference to Example 1, the heating time of each heating is 250 min.
[0079] Experimental Example: In order to explore the influence of the preparation parameters of each example on the performance of the titanium alloy pie piece, the titanium alloy pie pieces prepared in each example are subjected to ultrasonic flaw detection and performance test, and the specific exploration is as follows:
[0080] 1. Explore the influence of chamfer size on the performance of titanium alloy pie piece
[0081] With reference to Examples 1, 2, 3 and Comparative Examples 1, 2, the performance of the titanium alloy pie piece under different chamfer sizes is shown in Table 1 as follows:
[0082] Table 1 Performance of titanium alloy pie piece under different chamfer sizes
[0083]
[0084]
[0085] From the data in Table 1, it can be seen that Examples 1, 2 and 3 are compared: the titanium alloy pie piece of Example 1 has the highest flaw detection level and tensile strength, which may be because the titanium alloy pie piece of Example 1 has the most uniform structure and fewer internal cracks under the chamfer size of Example 1, so the chamfer size of Example 1 is optimal.
[0086] Example 1 vs. Comparative Example 1: After the titanium alloy bar is not chamfered, the titanium alloy cake piece flaw detection level and tensile strength are both reduced, which may be due to the fact that after the titanium alloy bar is not chamfered, the microstructure uniformity of the titanium alloy cake piece is poor, so the titanium alloy cake piece preparation method selected in Example 1 is optimal.
[0087] Example 1 vs. Comparative Example 2: After always elongating and upsetting along the axial direction during free forging, the titanium alloy cake piece flaw detection level and tensile strength are both reduced, which may be because always elongating and upsetting along the axial direction causes the radial dendrites of the titanium alloy cake piece to be unable to be fully broken, so the forging method selected in Example 1 is optimal.
[0088] 2. Explore the effect of heating temperature on the performance of titanium alloy cake pieces
[0089] The performance of titanium alloy cake pieces under different heating temperatures is shown in Table 2 below, with Example 1, 4, 5, and as an experimental comparison:
[0090] Table 2 Performance of titanium alloy cake pieces under different heating temperatures
[0091] Group Flaw detection level Tensile strength Example 1 ≤Φ0.6 ~ 9dB 1340MPa Example 4 ≤Φ1.0 ~ 9dB 1292MPa Example 5 ≤Φ0.8 ~ 9dB 1308MPa
[0092] From the data in Table 2, Example 1, 4, 5: the titanium alloy cake piece flaw detection level and tensile strength of Example 1 are the highest, which may be because the titanium alloy cake piece of Example 1 has fine internal grains, so the heating temperature selected in Example 1 is optimal.
[0093] 3. Explore the effect of heating time on the performance of titanium alloy cake pieces
[0094] The performance of titanium alloy cake pieces under different heating times is shown in Table 3 below, with Example 1, 6, 7, and Comparative Example 3 as experimental comparisons:
[0095] Table 3 Performance of titanium alloy cake pieces under different heating times
[0096]
[0097]
[0098] From the data in Table 3, Example 1, 6, 7: the titanium alloy cake piece flaw detection level and tensile strength of Example 1 are the highest, which may be because the titanium alloy cake piece of Example 1 has less internal segregation and uniform microstructure, so the heating time selected in Example 1 is optimal.
[0099] Example 1 vs. Comparative Example 3: After the heating time for each heating is fixed, the titanium alloy cake piece flaw detection level and tensile strength are both reduced, which may be because after the heating time is fixed, the internal grains of the titanium alloy cake piece become large and the microstructure consistency is poor, so the heating time selected in Example 1 is optimal.
[0100] 4. Explore the effect of primary annealing parameters on the performance of titanium alloy disc
[0101] With examples 1, 8, 9, 10, 11 as experimental comparison, the performance of titanium alloy disc under different primary annealing parameters is shown in Table 4 as follows:
[0102] Table 4 Performance of titanium alloy disc under different primary annealing parameters
[0103] Group Flaw detection level Tensile strength Example 1 ≤Φ0.6 ~ 9dB 1340MPa Example 8 ≤Φ0.8 ~ 9dB 1305MPa Example 9 ≤Φ0.8 ~ 9dB 1288MPa Example 10 ≤Φ1.0 ~ 9dB 1273MPa Example 11 ≤Φ0.8 ~ 9dB 1291MPa
[0104] From the data in Table 4, compared with examples 1, 8, 9, 10, 11: the titanium alloy disc of example 1 has the highest flaw detection level and tensile strength, which may be because the titanium alloy disc of example 1 has fine internal grains and fewer organizational defects, so the primary annealing parameters selected by example 1 are optimal.
[0105] 5. Explore the effect of secondary annealing parameters on the performance of titanium alloy disc
[0106] With examples 1, 12, 13, 14, 15 as experimental comparison, the performance of titanium alloy disc under different secondary annealing parameters is shown in Table 5 as follows:
[0107] Table 5 Performance of titanium alloy disc under different secondary annealing parameters
[0108]
[0109]
[0110] From the data in Table 5, compared with examples 1, 12, 13, 14, 15: the titanium alloy disc of example 1 has the highest flaw detection level and tensile strength, which may be because the internal metastable β phase of the titanium alloy disc of example 1 can be fully decomposed, and less brittle phase is precipitated, so the secondary annealing parameters selected by example 1 are optimal.
Claims
1. A method for preparing high-flaw-detection-level titanium alloy discs based on free forging, characterized in that, Includes the following steps: S1, Material feeding The two ends of the titanium alloy bar are chamfered to obtain the billet; S2, Free Forging Step 1: The billet is drawn and upset once along the axial direction to obtain a square billet, and then drawn and upset once along the length of the cross-section of the square billet. Step 2: The billet is drawn and upset once along the length of its cross-section, and then drawn and upset once along the width of its cross-section. Step 3: The billet is drawn and upset once along the width of the billet cross section, then drawn again along the axial direction, then upset along the axial direction, and finally rolled and flattened to obtain the forging. Before each drawing and upsetting operation, the billet is heated once, and the heating temperature is 35-55℃ below the β phase transformation point; S3, Heat Treatment The forging is subjected to a first annealing and a second annealing to obtain a titanium alloy disc.
2. The method for preparing a high-flaw-detection level titanium alloy disc based on free forging according to claim 1, characterized in that, In step S1, the chamfer is R15 to R20.
3. The method for preparing a high-flaw-detection level titanium alloy disc based on free forging according to claim 1, characterized in that, In step S2, If the billet temperature is ≥850℃ during each heating, the heating time is 0.4~0.6Lmin; If the billet temperature is less than 850℃, the heating time is 0.7 to 0.9 L / min. If the billet temperature is <40℃, the heating time is 240-260 min; Where L is the current length of the billet.
4. The method for preparing a high-flaw-detection level titanium alloy disc based on free forging according to claim 3, characterized in that, In step S2, the length deformation of the billet in both the drawing and upsetting steps is between 35% and 50%.
5. The method for preparing a high-flaw-detection level titanium alloy disc based on free forging according to claim 1, characterized in that, In step S2, after step 1 and step 2 are completed, the billet is cooled to room temperature by air cooling, and after step 3 is completed, the billet is cooled to room temperature by water cooling.
6. The method for preparing a high-flaw-detection level titanium alloy disc based on free forging according to claim 1, characterized in that, In step S3, the single annealing method is as follows: the forging is held at 45-55°C below the β phase transformation point for 0.5-1.5 hours, then heated by 10-20°C, held for 220-240 minutes, and then air-cooled.
7. The method for preparing a high-flaw-detection level titanium alloy disc based on free forging according to claim 1, characterized in that, In step S3, the secondary annealing method is as follows: heat the forging to 520-540℃, hold it at that temperature for 5-7 hours, and then air cool it.