Preparation method of titanium alloy forged rod
By employing a composite forging technology combining axial upsetting, diagonal piercing, and alternating cooling processes, the problem of insufficient strength in titanium alloy forged bars was solved, resulting in improved grain refinement and microstructure uniformity, thereby enhancing tensile strength and reliability.
Patent Information
- Application Number
- CN202511353493.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-22
- Publication Date
- 2025-11-11
AI Technical Summary
Existing methods for preparing titanium alloy forged bars suffer from problems such as large grain size and poor microstructure uniformity, resulting in insufficient strength and affecting reliability in use.
The composite forging technology of axial upsetting and diagonal drawing is adopted, combined with air cooling, oil cooling and water cooling alternating cyclic cooling process, and large deformation by alternating loading in multiple directions to promote dynamic recrystallization and grain refinement.
It significantly improves the tensile strength of titanium alloy forged bars by 15-20%, enhances their reliability, and is particularly suitable for high-end equipment manufacturing.
Smart Images
Figure CN120920641A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of titanium alloy forging bar manufacturing technology, and in particular to a method for preparing titanium alloy forging bars. Background Technology
[0002] Titanium alloy forgings are a key basic material in high-end equipment manufacturing, and their performance directly affects the reliability of core components in aerospace, energy equipment, and marine engineering. Currently, titanium alloy forgings are mainly prepared through multi-heat upsetting and cooling processes. However, the resulting titanium alloy forgings suffer from problems such as large grain size and poor microstructure uniformity, which seriously affect their strength and reduce their reliability in use. Summary of the Invention
[0003] The technical problem solved by this invention is to provide a method for preparing titanium alloy forging rods with high strength.
[0004] The technical solution adopted by this invention to solve its technical problem is: a method for preparing titanium alloy forged bars, comprising the following steps:
[0005] a. The first titanium alloy ingot is obtained by smelting, and the first titanium alloy ingot is peeled and flattened.
[0006] b. The first titanium alloy ingot is shaped to obtain a second titanium alloy ingot in the shape of a cuboid. A first coordinate system XYZ is established with one vertex of the second titanium alloy ingot as the origin O of the coordinate system. The length direction of the second titanium alloy ingot is the X-axis direction, the width direction is the Y-axis direction, and the height direction is the Z-axis direction.
[0007] c. The second titanium alloy ingot is upset using a diagonal upsetting method with axial reversal to obtain a primary forging billet. The coordinate system of the primary forging billet is the first coordinate system XYZ. Specifically: First, the second titanium alloy ingot is heated to a temperature of T + (150-250)℃ and held for 6-8 hours, where T is the phase transformation temperature. Then, the second titanium alloy ingot is upset along the Z-axis. After upset, it is stretched twice along the two diagonal directions of the projection of the second titanium alloy ingot in the XOZ plane along the Y-axis. During stretching, the second titanium alloy ingot is rotated 90° clockwise around the Y-axis, and the first coordinate system XYZ of the second titanium alloy ingot becomes the second coordinate system X'YZ'. Then, the second titanium alloy ingot is upset again along the Y-axis. After upsetting, the second titanium alloy ingot is lengthened twice along the two diagonal directions projected onto the YOZ' plane. During the lengthening, the second titanium alloy ingot is rotated 90° clockwise around the X' axis, and the second coordinate system X'YZ' of the second titanium alloy ingot becomes the third coordinate system X'Y'Z. Finally, the second titanium alloy ingot is upset along the X' axis. After upsetting, the second titanium alloy ingot is lengthened twice along the two diagonal directions projected onto the X'OY' plane. During the lengthening, the second titanium alloy ingot is rotated 90° clockwise around the Z axis, and the third coordinate system X'Y'Z of the second titanium alloy ingot is restored to the first coordinate system XYZ. After air cooling and grinding, the second titanium alloy ingot is obtained as a forging billet.
[0008] d. The primary forging billet undergoes an odd number of upsetting and drawing processes. The upsetting and drawing method is axial upsetting and diagonal edge drawing. After each forging process, oil cooling and water cooling are used alternately for temperature control to obtain a secondary forging billet. The coordinate system of the secondary forging billet is the first coordinate system XYZ. Specifically, the primary forging billet is heated to a temperature of T+(20-40)℃ and held for 4-6 hours, where T is the phase transformation point temperature. The upsetting and drawing process for each odd number of forging processes is as follows: First, the primary forging billet is upset along the Z-axis. After upsetting, it is drawn twice along the two diagonal directions of the projection of the primary forging billet in the YOZ plane along the X-axis. During the drawing process, the primary forging billet is rotated 90° clockwise around the X-axis. The first coordinate system XYZ of the primary forging billet becomes the fourth coordinate system. The coordinate system is XY'Z'. Then, the forging billet is upset along the X-axis. After upset, it is lengthened twice along the two diagonal directions of the projection of the forging billet in the XOZ' plane. During the lengthening, the forging billet is rotated 90° clockwise around the Y' axis, and the fourth coordinate system XY'Z' of the forging billet becomes the third coordinate system X'Y'Z. Finally, the forging billet is upset along the Y' axis. After upset, it is lengthened twice along the two diagonal directions of the projection of the forging billet in the X'OY' plane. During the lengthening, the forging billet is rotated 90° clockwise around the Z-axis, and the third coordinate system X'Y'Z of the forging billet is restored to the first coordinate system XYZ. Then, the forging billet is oil-cooled and polished.
[0009] The upsetting and drawing process for every even number of firings is as follows: First, the forging billet is upset along the Z-axis. After upsetting, it is drawn twice along the two diagonal directions projected onto the XOZ plane, along the Y-axis. During the drawing process, the forging billet is rotated 90° clockwise around the Y-axis, transforming the first coordinate system XYZ of the forging billet into the second coordinate system X'YZ'. Then, the forging billet is upset along the Y-axis. After upsetting, it is drawn twice along the X'-axis along the two diagonal directions projected onto the YOZ' plane. The forging billet is rotated 90° clockwise around the X' axis, and the second coordinate system X'YZ' of the forging billet becomes the third coordinate system X'Y'Z. Finally, the forging billet is upset along the X' axis. After upset, it is stretched twice along the two diagonals of the projection of the forging billet in the X'OY' plane along the Z axis. During the stretching, the forging billet is rotated 90° clockwise around the Z axis, and the third coordinate system X'Y'Z of the forging billet is restored to the first coordinate system XYZ. Then, the forging billet is water-cooled and polished.
[0010] e. The secondary forging billet is subjected to an even number of upsetting and drawing processes. After each odd number of upsetting and drawing processes, oil cooling is performed, and after each even number of upsetting and drawing processes, water cooling is performed to obtain a tertiary forging billet. Specifically, the secondary forging billet is heated to a temperature of T+(20-60)℃ and held for 2-4 hours, where T is the phase transformation point temperature. The first upsetting and drawing process is as follows: First, the secondary forging billet is upset along the Z-axis direction. After upset, it is drawn twice along the two diagonal directions of the projection of the secondary forging billet in the XOZ plane along the Y-axis direction. During the drawing process, the secondary forging billet is rotated 90° clockwise around the Y-axis, and the first coordinate system XYZ of the secondary forging billet becomes the second coordinate system X'YZ'. Then, the secondary forging billet is upset along the Y-axis. After upset, it is lengthened twice along the two diagonals projected onto the YOZ' plane. During the lengthening, the secondary forging billet is rotated 90° clockwise around the X' axis, and the second coordinate system X'YZ' of the secondary forging billet becomes the third coordinate system X'Y'Z. Finally, the secondary forging billet is upset along the X' axis. After upset, it is lengthened twice along the two diagonals projected onto the X'OY' plane. During the lengthening, the secondary forging billet is rotated 90° clockwise around the Z-axis, and the third coordinate system X'Y'Z of the secondary forging billet is restored to the first coordinate system XYZ.
[0011] The subsequent upsetting and drawing process is as follows: the secondary forging billet is upset along the Z-axis direction. After upsetting, it is drawn twice along the two diagonal directions of the projection of the secondary forging billet in the XOY plane along the Z-axis direction. During the drawing, the secondary forging billet is rotated 90° clockwise around the Z-axis. The first coordinate system XYZ of the secondary forging billet becomes the third coordinate system X'Y'Z. Then the secondary forging billet is flipped again, and the coordinate system of the secondary forging billet is restored to the first coordinate system XYZ.
[0012] f. The three-forged billet is hot-rolled into a final forging shape using a finishing mill to obtain a titanium alloy forged bar.
[0013] Furthermore, the intermediate alloy package and sponge titanium are melted 2-3 times in a vacuum arc remelting furnace to obtain the first titanium alloy ingot.
[0014] Furthermore, in step c, the deformation amount of the second titanium alloy ingot upsetting is 50-60% each time.
[0015] Furthermore, in step c, the deformation amount of the second titanium alloy ingot being drawn out each time is 45-55%.
[0016] Furthermore, in step d, the deformation amount of each upsetting of the forging billet is 45-55%.
[0017] Furthermore, in step d, the deformation amount of each forging billet elongation is 45-55%.
[0018] Furthermore, in step e, the deformation amount of the secondary forging billet during each upsetting is 35-45%.
[0019] The beneficial effects of this invention are as follows: This invention adopts a composite forging technology of axial upsetting and diagonal drawing, combined with corresponding forging methods. The initial forging adopts air cooling treatment. The relatively slow cooling method of air cooling can effectively improve the plastic deformation capacity of the material, providing a good microstructure basis for subsequent forging processing. During forging, an alternating cooling process of oil cooling and water cooling is adopted to achieve a dislocation density gradient distribution. With the help of water cooling before hot rolling and precise control of grain size by hot rolling forming, multi-dimensional forging promotes dynamic recrystallization and grain refinement through alternating loading of large deformation in multiple directions. This makes the titanium alloy forged bar have high strength while maintaining a certain elongation. In particular, the tensile strength of the titanium alloy forged bar is increased by 15-20%, which significantly improves the reliability of the titanium alloy forged bar and is conducive to its use in high-end equipment. Attached Figure Description
[0020] Figure 1 This is a schematic diagram (a) of the upsetting and drawing process of the second titanium alloy ingot in step c;
[0021] Figure 2 This is a schematic diagram (b) of the upsetting and drawing process of the second titanium alloy ingot in step c;
[0022] Figure 3 This is a schematic diagram (c) of the upsetting and drawing process of the second titanium alloy ingot in step c;
[0023] Figure 4 This is a schematic diagram (a) of the upsetting and drawing process of a forged billet in step d, where the process involves an odd number of upsetting and drawing operations.
[0024] Figure 5 This is a schematic diagram (b) of the upsetting and drawing process for each odd number of hot passes of a forging billet in step d;
[0025] Figure 6 This is a schematic diagram (c) of the upsetting and drawing process for each odd number of hot passes of a forging billet in step d;
[0026] Figure 7 This is a schematic diagram (a) of the upsetting and drawing process of a forged billet every even number of fires in step d;
[0027] Figure 8 This is a schematic diagram (b) of the upsetting and drawing process for an even number of hot passes of a forging billet in step d;
[0028] Figure 9 This is a schematic diagram (c) of the upsetting and drawing process of a forged billet for every even number of fires in step d;
[0029] Figure 10 This is a schematic diagram (a) of the first upsetting and drawing process of the secondary forging billet in step e;
[0030] Figure 11 This is a schematic diagram (b) of the first upsetting and drawing process of the secondary forging billet in step e;
[0031] Figure 12 This is a schematic diagram (c) of the first upsetting and drawing process of the secondary forging billet in step e;
[0032] Figure 13 This is a schematic diagram of the upsetting and drawing process after the secondary forging of the billet in step e. Detailed Implementation
[0033] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.
[0034] The method for preparing titanium alloy forged bars of the present invention includes the following steps:
[0035] a. The first titanium alloy ingot is obtained by smelting, and the first titanium alloy ingot is peeled and flattened.
[0036] b. The first titanium alloy ingot is shaped to obtain a second titanium alloy ingot in the shape of a cuboid. A first coordinate system XYZ is established with one vertex of the second titanium alloy ingot as the origin O of the coordinate system. The length direction of the second titanium alloy ingot is the X-axis direction, the width direction is the Y-axis direction, and the height direction is the Z-axis direction.
[0037] c. The second titanium alloy ingot is upset using a diagonal upsetting method with axial reversal to obtain a primary forging billet. The coordinate system of the primary forging billet is the first coordinate system XYZ. Specifically: First, the second titanium alloy ingot is heated to a temperature of T + (150-250)℃ and held for 6-8 hours, where T is the phase transformation temperature. Then, the second titanium alloy ingot is upset along the Z-axis. After upsetting, it is stretched twice along the two diagonal directions projected onto the XOZ plane along the Y-axis. During stretching, the second titanium alloy ingot is rotated 90° clockwise around the Y-axis. The first coordinate system XYZ of the second titanium alloy ingot becomes the second coordinate system X'YZ'. Figure 1 As shown; then, the second titanium alloy ingot is upset along the Y-axis. After upsetting, it is stretched twice along the two diagonal directions projected onto the YOZ' plane along the X' axis. During stretching, the second titanium alloy ingot is rotated 90° clockwise around the X' axis, and the second coordinate system X'YZ' of the second titanium alloy ingot becomes the third coordinate system X'Y'Z, as shown. Figure 2As shown; finally, the second titanium alloy ingot is upset along the X' axis. After upsetting, it is stretched twice along the two diagonal directions projected onto the X'OY' plane along the Z-axis. During stretching, the second titanium alloy ingot is rotated 90° clockwise around the Z-axis, and the third coordinate system X'Y'Z of the second titanium alloy ingot is restored to the first coordinate system XYZ, as shown. Figure 3 As shown, the second titanium alloy ingot is then subjected to water cooling and grinding to obtain a primary forging billet.
[0038] d. The primary forging billet undergoes an odd number of upsetting and drawing processes. The upsetting and drawing method is axial upsetting and diagonal edge drawing. After each forging process, water cooling and air cooling are used alternately for temperature control to obtain a secondary forging billet. The coordinate system of the secondary forging billet is the first coordinate system XYZ. Specifically, the primary forging billet is heated to a temperature of T+(20-40)℃ and held for 4-6 hours, where T is the phase transformation point temperature. The upsetting and drawing process for each odd number of forging processes is as follows: First, the primary forging billet is upset along the Z-axis. After upsetting, it is drawn twice along the two diagonal directions projected by the primary forging billet in the YOZ plane along the X-axis. During the drawing process, the primary forging billet is rotated 90° clockwise around the X-axis. The first coordinate system XYZ of the primary forging billet becomes the fourth coordinate system XY'Z'. Figure 4 As shown; then, the forging billet is upset along the X-axis, and after upset, it is elongated twice along the two diagonal directions of the projection of the forging billet in the XOZ' plane along the Y' axis. During the elongation, the forging billet is rotated 90° clockwise around the Y' axis, and the fourth coordinate system XY'Z' of the forging billet becomes the third coordinate system X'Y'Z, as shown. Figure 5 As shown; finally, the forging billet is upset along the Y' axis. After upset, it is stretched twice along the two diagonal directions of the projection of the forging billet in the X'OY' plane along the Z-axis. During the stretching, the forging billet is rotated 90° clockwise around the Z-axis, and the third coordinate system X'Y'Z of the forging billet is restored to the first coordinate system XYZ, as shown. Figure 6 As shown, the forging billet is then subjected to air cooling and grinding.
[0039] The upsetting and drawing process for each even-numbered firing cycle is as follows: Figure 3 As shown, the forging billet is first upset along the Z-axis. After upset, it is drawn twice along the two diagonal directions of the projection of the forging billet in the XOZ plane along the Y-axis. During the drawing, the forging billet is rotated 90° clockwise around the Y-axis, and the first coordinate system XYZ of the forging billet becomes the second coordinate system X'YZ'. Figure 7As shown; then, the forging billet is upset along the Y-axis. After upset, it is drawn twice along the two diagonal directions projected onto the YOZ' plane. During the drawing, the forging billet is rotated 90° clockwise around the X' axis, and the second coordinate system X'YZ' of the forging billet becomes the third coordinate system X'Y'Z, as shown. Figure 8 As shown; finally, the forging billet is upset along the X' axis. After upset, it is stretched twice along the two diagonal directions of the projection of the forging billet in the X'OY' plane along the Z-axis. During the stretching, the forging billet is rotated 90° clockwise around the Z-axis, and the third coordinate system X'Y'Z of the forging billet is restored to the first coordinate system XYZ, as shown. Figure 9 As shown, the forging billet is then subjected to water cooling and grinding.
[0040] e. The secondary forging billet undergoes an even number of upsetting and drawing processes. After each odd-numbered upsetting and drawing process, water cooling is applied, and after each even-numbered upsetting and drawing process, air cooling is applied, resulting in a tertiary forging billet. Specifically, the secondary forging billet is heated to a temperature of T + (20-60)℃ and held for 2-4 hours, where T is the phase transformation temperature. The first upsetting and drawing process is as follows: First, the secondary forging billet is upset along the Z-axis. After upsetting, it is drawn twice along the two diagonal directions projected onto the XOZ plane along the Y-axis. During drawing, the secondary forging billet is rotated 90° clockwise around the Y-axis, transforming the first coordinate system XYZ of the secondary forging billet into the second coordinate system X'YZ'. Figure 10 As shown; then, the secondary forging billet is upset along the Y-axis. After upset, it is elongated twice along the two diagonal directions projected onto the YOZ' plane in the X' axis. During elongation, the secondary forging billet is rotated 90° clockwise around the X' axis, and the second coordinate system X'YZ' of the secondary forging billet becomes the third coordinate system X'Y'Z, as shown. Figure 11 As shown; finally, the secondary forging billet is upset along the X' axis. After upset, it is stretched twice along the two diagonal directions projected onto the X'OY' plane along the Z-axis. During the stretching, the secondary forging billet is rotated 90° clockwise around the Z-axis, and the third coordinate system X'Y'Z of the secondary forging billet is restored to the first coordinate system XYZ, as shown. Figure 12 As shown;
[0041] The subsequent upsetting and drawing process is as follows: the secondary forging billet is upset along the Z-axis. After upsetting, it is drawn twice along the two diagonal directions of the projection of the secondary forging billet in the XOY plane along the Z-axis. During the drawing, the secondary forging billet is rotated 90° clockwise around the Z-axis, and the first coordinate system XYZ of the secondary forging billet becomes the third coordinate system X'Y'Z. Then, the secondary forging billet is rotated again, and the coordinate system of the secondary forging billet is restored to the first coordinate system XYZ. Figure 13As shown;
[0042] f. The three-forged billet is hot-rolled into a final forging shape using a finishing mill to obtain a titanium alloy forged bar.
[0043] To further improve the performance of the prepared titanium alloy forged bar, the preferred parameters for each step are as follows: In step a, the intermediate alloy package and sponge titanium are melted 2-3 times in a vacuum induction melting furnace to obtain the first titanium alloy ingot.
[0044] In step c, the deformation amount of the second titanium alloy ingot upsetting each time is 50-60%, and the deformation amount of the second titanium alloy ingot drawing each time is 45-55%.
[0045] In step d, the deformation amount of upsetting the forging billet each time is 45-55%, and the deformation amount of elongation of the forging billet each time is 45-55%.
[0046] In step e, the deformation amount of the secondary forging billet during each upsetting is 35-45%.
[0047] In step f, the three-forged billet is heated to T-(60-120)℃ and held for 2-4 hours before entering the finishing mill for final hot rolling. The rolls are preheated to 300℃-400℃ before rolling to finally obtain a titanium alloy forging bar with high dimensional accuracy.
[0048] This invention employs a composite forging technology combining axial upsetting and diagonal drawing, along with appropriate forging methods. The initial forging utilizes air cooling, a slower cooling process that effectively improves the material's plastic deformation capacity, providing a good microstructure for subsequent forging. During forging, an alternating oil and water cooling process is used to achieve a dislocation density gradient distribution. This is supplemented by water cooling before hot rolling and precise control of grain size during hot rolling forming. Multi-dimensional forging, through alternating large deformation loading in multiple directions, promotes dynamic recrystallization and grain refinement, resulting in titanium alloy forged bars with high strength while maintaining a certain elongation. In particular, the tensile strength of the titanium alloy forged bars is increased by 15-20%, significantly improving their reliability and making them suitable for use in high-end equipment.
[0049] Example
[0050] The preparation of a 120mm TA18 titanium alloy forged bar includes the following steps:
[0051] a. The intermediate alloy package and sponge titanium are melted three times in a vacuum induction melting furnace to obtain a first titanium alloy ingot with a diameter of Φ260mm and a height of 500mm. The first titanium alloy ingot is peeled and flattened to obtain an ingot with a diameter of Φ250mm.
[0052] b. The first titanium alloy ingot is shaped to obtain a second titanium alloy ingot with a cuboid shape. The length and width of the second titanium alloy ingot are both Φ240mm. A first coordinate system XYZ is established with one vertex of the second titanium alloy ingot as the origin O of the coordinate system. The length direction of the second titanium alloy ingot is the X-axis direction, the width direction is the Y-axis direction, and the height direction is the Z-axis direction.
[0053] c. The second titanium alloy ingot is upset using a diagonal upsetting method with axial reversal to obtain a primary forging billet. The coordinate system of the primary forging billet is the first coordinate system XYZ. Specifically, the second titanium alloy ingot is first heated to 1100℃ and held at that temperature for 6 hours. Figure 1 As shown, the second titanium alloy ingot is then upset along the Z-axis. After upseting, it is elongated twice along the two diagonal directions of the projection of the second titanium alloy ingot into the XOZ plane along the Y-axis. During elongation, the second titanium alloy ingot is rotated 90° clockwise around the Y-axis, and the first coordinate system XYZ of the second titanium alloy ingot becomes the second coordinate system X'YZ'. Then, the second titanium alloy ingot is upset again along the Y-axis. After upseting, it is elongated twice along the two diagonal directions of the projection of the second titanium alloy ingot into the YOZ' plane along the X' axis. During elongation, the second titanium alloy ingot is rotated 90° clockwise around the X' axis, and the second titanium alloy ingot... The second coordinate system X'YZ' is transformed into the third coordinate system X'Y'Z; finally, the second titanium alloy ingot is upset along the X' axis, and after upset, it is stretched twice along the two diagonal directions of the projection of the second titanium alloy ingot in the X'OY' plane along the Z axis. During the stretching, the second titanium alloy ingot is rotated 90° clockwise around the Z axis, and the third coordinate system X'Y'Z of the second titanium alloy ingot is restored to the first coordinate system XYZ. After the second titanium alloy ingot is air-cooled and polished, a forging billet is obtained; the deformation amount of each upset of the second titanium alloy ingot is 55%, and the deformation amount of each stretching of the second titanium alloy ingot is 50%.
[0054] d. The primary forging billet is subjected to three upsetting and drawing processes. The upsetting and drawing method is axial upsetting and diagonal edge drawing. After each forging process, oil cooling and water cooling are used for alternating temperature control to obtain the secondary forging billet. The coordinate system of the secondary forging billet is the first coordinate system XYZ.
[0055] The first upsetting and drawing process is as follows: The forging billet is heated to 950℃ and held for 4 hours. First, the forging billet is upset along the Z-axis. After upsetting, it is drawn twice along the two diagonal directions projected onto the YOZ plane. During the drawing, the forging billet is rotated 90° clockwise around the X-axis, and the first coordinate system XYZ of the forging billet becomes the fourth coordinate system XY'Z'. Then, the forging billet is upset along the X-axis. After upsetting, it is drawn twice along the two diagonal directions projected onto the XOZ' plane. The forging billet is lengthened along the Y' axis. During the lengthening process, the forging billet is rotated 90° clockwise around the Y' axis, and the fourth coordinate system XY'Z' of the forging billet becomes the third coordinate system X'Y'Z. Finally, the forging billet is upset along the Y' axis. After upset, the forging billet is lengthened twice along the two diagonals of the projection of the forging billet in the X'OY' plane. During the lengthening process, the forging billet is rotated 90° clockwise around the Z axis, and the third coordinate system X'Y'Z of the forging billet is restored to the first coordinate system XYZ. Then, the forging billet is oil-cooled and polished.
[0056] The second upsetting and drawing process is as follows: The primary forging billet is heated to 900℃ and held for 4 hours. First, the primary forging billet is upset along the Z-axis. After upsetting, it is drawn twice along the two diagonal directions projected onto the XOZ plane, along the Y-axis. During the drawing, the primary forging billet is rotated 90° clockwise around the Y-axis, and the first coordinate system XYZ of the primary forging billet becomes the second coordinate system X'YZ'. Then, the primary forging billet is upset along the Y-axis. After upsetting, it is drawn twice along the two diagonal directions projected onto the YOZ' plane. The forging billet is lengthened along the X' axis. During the lengthening process, the forging billet is rotated 90° clockwise around the X' axis, and the second coordinate system X'YZ' of the forging billet becomes the third coordinate system X'Y'Z. Finally, the forging billet is upset along the X' axis. After upset, it is lengthened twice along the two diagonals of the projection of the forging billet in the X'OY' plane along the Z axis. During the lengthening process, the forging billet is rotated 90° clockwise around the Z axis, and the third coordinate system X'Y'Z of the forging billet is restored to the first coordinate system XYZ. The forging billet is then water-cooled and polished.
[0057] The third upsetting and drawing process is as follows: The primary forging billet is heated to 920℃ and held for 4 hours. First, the primary forging billet is upset along the Z-axis. After upsetting, it is drawn twice along the two diagonal directions projected onto the YOZ plane. During the drawing process, the primary forging billet is rotated 90° clockwise around the X-axis, and the first coordinate system XYZ of the primary forging billet becomes the fourth coordinate system XY'Z'. Then, the primary forging billet is upset along the X-axis. After upsetting, it is drawn twice along the two diagonal directions projected onto the XOZ' plane. The forging billet is lengthened along the Y' axis. During the lengthening process, the forging billet is rotated 90° clockwise around the Y' axis, and the fourth coordinate system XY'Z' of the forging billet becomes the third coordinate system X'Y'Z. Finally, the forging billet is upset along the Y' axis. After upset, the forging billet is lengthened twice along the two diagonals of the projection of the forging billet in the X'OY' plane. During the lengthening process, the forging billet is rotated 90° clockwise around the Z axis, and the third coordinate system X'Y'Z of the forging billet is restored to the first coordinate system XYZ. The forging billet is then air-cooled and polished.
[0058] e. The secondary forging billet is subjected to two upsetting and drawing processes to obtain the tertiary forging billet;
[0059] The first upsetting and drawing process is as follows: The secondary forging billet is heated to 860℃ and held for 4 hours. First, the secondary forging billet is upset along the Z-axis. After upsetting, it is drawn twice along the two diagonals projected onto the XOZ plane along the Y-axis. During the drawing, the secondary forging billet is rotated 90° clockwise around the Y-axis, and the first coordinate system XYZ of the secondary forging billet becomes the second coordinate system X'YZ'. Then, the secondary forging billet is upset along the Y-axis. After upsetting, it is drawn twice along the two diagonals projected onto the YOZ' plane along the Y-axis. The secondary forging billet is lengthened twice along the X' axis in the diagonal direction. During the lengthening process, the secondary forging billet is rotated 90° clockwise around the X' axis, and the second coordinate system X'YZ' of the secondary forging billet becomes the third coordinate system X'Y'Z. Finally, the secondary forging billet is upset along the X' axis. After upset, it is lengthened twice along the Z axis in the two diagonal directions projected by the secondary forging billet in the X'OY' plane. During the lengthening process, the secondary forging billet is rotated 90° clockwise around the Z axis, and the third coordinate system X'Y'Z of the secondary forging billet is restored to the first coordinate system XYZ.
[0060] The second upsetting and drawing process is as follows: the secondary forging billet is heated to 890℃ and held for 4 hours. The secondary forging billet is upset along the Z-axis. After upsetting, it is drawn twice along the two diagonal directions of the projection of the secondary forging billet in the XOY plane along the Z-axis. During the drawing, the secondary forging billet is rotated 90° clockwise around the Z-axis. The first coordinate system XYZ of the secondary forging billet becomes the third coordinate system X'Y'Z. The secondary forging billet is then flipped again, and the coordinate system of the secondary forging billet is restored to the first coordinate system XYZ.
[0061] f. Heat the three-forged billet to 840℃ and hold for 2 hours. Then, put it into the finishing mill for final hot rolling. Before rolling, preheat the rolls to 400℃. After machining, obtain a Φ120mm TA18 titanium alloy forged bar with high dimensional accuracy.
[0062] After testing, the titanium alloy forged bar prepared in the example showed a smooth appearance, a surface roughness Ra of 1.9 μm, a tensile strength of 911 MPa, and an elongation of 9.5%, indicating high strength and good performance.
Claims
1. A method for preparing titanium alloy forged bars, characterized in that, Includes the following steps: a. The first titanium alloy ingot is obtained by smelting, and the first titanium alloy ingot is peeled and flattened. b. The first titanium alloy ingot is shaped to obtain a second titanium alloy ingot in the shape of a cuboid. A first coordinate system XYZ is established with one vertex of the second titanium alloy ingot as the origin O of the coordinate system. The length direction of the second titanium alloy ingot is the X-axis direction, the width direction is the Y-axis direction, and the height direction is the Z-axis direction. c. The second titanium alloy ingot is upset using a diagonal upsetting method with axial reversal to obtain a primary forging billet. The coordinate system of the primary forging billet is the first coordinate system XYZ. Specifically: First, the second titanium alloy ingot is heated to a temperature of T + (150-250)℃ and held for 6-8 hours, where T is the phase transformation temperature. Then, the second titanium alloy ingot is upset along the Z-axis. After upset, it is stretched twice along the two diagonal directions of the projection of the second titanium alloy ingot in the XOZ plane along the Y-axis. During stretching, the second titanium alloy ingot is rotated 90° clockwise around the Y-axis, and the first coordinate system XYZ of the second titanium alloy ingot becomes the second coordinate system X'YZ'. Then, the second titanium alloy ingot is upset again along the Y-axis. After upsetting, the second titanium alloy ingot is lengthened twice along the two diagonal directions projected onto the YOZ' plane. During the lengthening, the second titanium alloy ingot is rotated 90° clockwise around the X' axis, and the second coordinate system X'YZ' of the second titanium alloy ingot becomes the third coordinate system X'Y'Z. Finally, the second titanium alloy ingot is upset along the X' axis. After upsetting, the second titanium alloy ingot is lengthened twice along the two diagonal directions projected onto the X'OY' plane. During the lengthening, the second titanium alloy ingot is rotated 90° clockwise around the Z axis, and the third coordinate system X'Y'Z of the second titanium alloy ingot is restored to the first coordinate system XYZ. After air cooling and grinding, the second titanium alloy ingot is obtained as a forging billet. d. The primary forging billet undergoes an odd number of upsetting and drawing processes. The upsetting and drawing method is axial upsetting and diagonal edge drawing. After each forging process, oil cooling and water cooling are used alternately for temperature control to obtain a secondary forging billet. The coordinate system of the secondary forging billet is the first coordinate system XYZ. Specifically, the primary forging billet is heated to a temperature of T+(20-40)℃ and held for 4-6 hours, where T is the phase transformation point temperature. The upsetting and drawing process for each odd number of forging processes is as follows: First, the primary forging billet is upset along the Z-axis. After upsetting, it is drawn twice along the two diagonal directions of the projection of the primary forging billet in the YOZ plane along the X-axis. During the drawing process, the primary forging billet is rotated 90° clockwise around the X-axis. The first coordinate system XYZ of the primary forging billet becomes the fourth coordinate system. The coordinate system is XY'Z'. Then, the forging billet is upset along the X-axis. After upset, it is lengthened twice along the two diagonal directions of the projection of the forging billet in the XOZ' plane. During the lengthening, the forging billet is rotated 90° clockwise around the Y' axis, and the fourth coordinate system XY'Z' of the forging billet becomes the third coordinate system X'Y'Z. Finally, the forging billet is upset along the Y' axis. After upset, it is lengthened twice along the two diagonal directions of the projection of the forging billet in the X'OY' plane. During the lengthening, the forging billet is rotated 90° clockwise around the Z-axis, and the third coordinate system X'Y'Z of the forging billet is restored to the first coordinate system XYZ. Then, the forging billet is oil-cooled and polished. The upsetting and drawing process for every even number of firings is as follows: First, the forging billet is upset along the Z-axis. After upsetting, it is drawn twice along the two diagonal directions projected onto the XOZ plane, along the Y-axis. During the drawing process, the forging billet is rotated 90° clockwise around the Y-axis, transforming the first coordinate system XYZ of the forging billet into the second coordinate system X'YZ'. Then, the forging billet is upset along the Y-axis. After upsetting, it is drawn twice along the X'-axis along the two diagonal directions projected onto the YOZ' plane. The forging billet is rotated 90° clockwise around the X' axis, and the second coordinate system X'YZ' of the forging billet becomes the third coordinate system X'Y'Z. Finally, the forging billet is upset along the X' axis. After upset, it is stretched twice along the two diagonals of the projection of the forging billet in the X'OY' plane along the Z axis. During the stretching, the forging billet is rotated 90° clockwise around the Z axis, and the third coordinate system X'Y'Z of the forging billet is restored to the first coordinate system XYZ. Then, the forging billet is water-cooled and polished. e. The secondary forging billet is subjected to an even number of upsetting and drawing processes. After each odd number of upsetting and drawing processes, oil cooling is performed, and after each even number of upsetting and drawing processes, water cooling is performed to obtain a tertiary forging billet. Specifically, the secondary forging billet is heated to a temperature of T+(20-60)℃ and held for 2-4 hours, where T is the phase transformation point temperature. The first upsetting and drawing process is as follows: First, the secondary forging billet is upset along the Z-axis direction. After upset, it is drawn twice along the two diagonal directions of the projection of the secondary forging billet in the XOZ plane along the Y-axis direction. During the drawing process, the secondary forging billet is rotated 90° clockwise around the Y-axis, and the first coordinate system XYZ of the secondary forging billet becomes the second coordinate system X'YZ'. Then, the secondary forging billet is upset along the Y-axis. After upset, it is lengthened twice along the two diagonals projected onto the YOZ' plane. During the lengthening, the secondary forging billet is rotated 90° clockwise around the X' axis, and the second coordinate system X'YZ' of the secondary forging billet becomes the third coordinate system X'Y'Z. Finally, the secondary forging billet is upset along the X' axis. After upset, it is lengthened twice along the two diagonals projected onto the X'OY' plane. During the lengthening, the secondary forging billet is rotated 90° clockwise around the Z-axis, and the third coordinate system X'Y'Z of the secondary forging billet is restored to the first coordinate system XYZ. The subsequent upsetting and drawing process is as follows: the secondary forging billet is upset along the Z-axis direction. After upsetting, it is drawn twice along the two diagonal directions of the projection of the secondary forging billet in the XOY plane along the Z-axis direction. During the drawing, the secondary forging billet is rotated 90° clockwise around the Z-axis. The first coordinate system XYZ of the secondary forging billet becomes the third coordinate system X'Y'Z. Then the secondary forging billet is flipped again, and the coordinate system of the secondary forging billet is restored to the first coordinate system XYZ. f. The three-forged billet is hot-rolled into a final forging shape using a finishing mill to obtain a titanium alloy forged bar.
2. The method for preparing titanium alloy forged bars as described in claim 1, characterized in that: In step a, the intermediate alloy package and sponge titanium are melted 2-3 times in a vacuum arc remelting furnace to obtain the first titanium alloy ingot.
3. The method for preparing titanium alloy forged bars as described in claim 1, characterized in that: In step c, the deformation amount of the second titanium alloy ingot upsetting is 50-60% each time.
4. The method for preparing titanium alloy forged bars as described in claim 3, characterized in that: In step c, the deformation amount of the second titanium alloy ingot is 45-55% each time it is drawn out.
5. The method for preparing titanium alloy forged bars as described in claim 1, characterized in that: In step d, the deformation amount of each upsetting of the forging billet is 45-55%.
6. The method for preparing titanium alloy forged bars as described in claim 5, characterized in that: In step d, the deformation amount of each forging billet is 45-55% during each elongation.
7. The method for preparing titanium alloy forged bars according to any one of claims 1 to 6, characterized in that: In step e, the deformation amount of the secondary forging billet during each upsetting is 35-45%.