CN115338353A

CN115338353A - Preparation process of high-uniformity TC25G high-temperature titanium alloy large-size fine-grain blisk

Info

Publication number: CN115338353A
Application number: CN202210959278.6A
Authority: CN
Inventors: 赵子博; 杨久旭; 王清江; 孙昊; 张博华; 刘建荣; 陈志勇; 朱绍祥; 李文渊; 王磊; 刘建
Original assignee: Institute of Metal Research of CAS
Current assignee: Institute of Metal Research of CAS
Priority date: 2022-08-10
Filing date: 2022-08-10
Publication date: 2022-11-15

Abstract

The invention discloses a preparation process of a high-uniformity TC25G high-temperature titanium alloy large-size fine-grain blisk, which comprises the steps of completing cogging forging of an alloy cast ingot at 1100-1200 ℃, then performing upsetting and drawing deformation on the obtained blank for 1 fire time at 10-30 ℃ above a beta phase transition point, performing water cooling after forging, heating the blank to 800-840 ℃, keeping the temperature for 6 h-10 h, then heating the blank to 920-960 ℃ along with a furnace for forging, then performing upsetting deformation on the blank for 6-8 fire times at 80-20 ℃ below the beta phase transition point, and then forming the blank at 60-40 ℃ below the beta phase transition point to obtain a forged blank; and finally, carrying out solid solution and aging heat treatment on the obtained forging stock to finally obtain the blisk forging blank. The process is suitable for preparing the blisk forge piece with the height of 600mm to 1300mm and the height of 60mm to 120mm, and the structure uniformity and the performance of the forge piece are superior to those of the traditional process.

Description

Preparation process of high-uniformity TC25G high-temperature titanium alloy large-size fine-grain blisk

Technical Field

The invention belongs to the field of new material processing, and particularly relates to a preparation process of a high-uniformity TC25G high-temperature titanium alloy large-size fine-grain blisk.

Background

The TC25G titanium alloy is an alpha + beta two-phase titanium alloy, has three-high characteristics of high temperature resistance, high strength and high toughness, and has a long service temperature of 550 ℃. Compared with the traditional two-phase titanium alloy (such as TA15, TC4, TC11 and TA 12A), the comprehensive performance of the TC25G alloy forging, the ring and the casting has obvious advantages; and the performance advantage of TC25G becomes more pronounced with increasing temperature. The TC25G alloy is mature and applied to Russian engines, and sound technical standards or process specifications are established. The working life of the rotor can reach more than 6000h below 500 ℃, the working life of the rotor can reach more than 3000h at 550 ℃, the rotor is mainly used for a wheel disc (a disc drum electron beam welding structure) and blades of a P II 33 compressor rotor, the usage amount of the rotor is more on other engines manufactured in Russia, and the rotor is also used for installing stator parts such as edges, a casing and the like besides a rotating part. TC25G is a necessary material of a 450-550 ℃ high-pressure compressor of the Russian advanced aeroengine.

The method has the advantages that the sizes of the titanium alloy bar and the forged piece are improved through optimization of the hot working process, and meanwhile, the stability and the performance consistency are continuously pursued by material researchers, and are also one of the technical difficulties to be solved urgently in the forging field.

Disclosure of Invention

The invention aims to provide a preparation process of a high-uniformity TC25G high-temperature titanium alloy large-size fine-grain blisk. Compared with the traditional process, the process is suitable for preparing the large-size blisk forge piece, and the structure uniformity and the metallurgical quality stability of the forge piece are remarkably improved compared with the traditional process. The method has the advantages of simple operation, short flow, high stability and suitability for industrial production.

The invention provides a preparation process of a high-uniformity TC25G high-temperature titanium alloy large-size fine-grain blisk, which comprises the following specific steps:

step 1) firstly heating an alloy ingot to 1100-1200 ℃, preserving heat for 15-35 h, discharging from a furnace and forging to finish 1-time upsetting and drawing deformation; then the forging and drawing deformation is finished for 1 time after the furnace is returned and the temperature is kept for 1 to 2 hours, and the pressing deformation rate of each upsetting is 0.2s ^-1 ～0.08s ^-1 Single upsetting deformation is not less than 50%, and air cooling is carried out after forging to obtain a blank;

step 2) performing 1-time hot upsetting and drawing deformation on the blank obtained in the step 1) at the temperature of 10-30 ℃ above the beta transformation point, wherein the pressing deformation rate under upsetting is 0.2s ^-1 ～0.08s ^-1 Upsetting deformation is more than or equal to 50%, and water cooling is carried out after forging;

step 3) heating the blank to 800-840 ℃, preserving heat for 6-10 h, then heating to 920-960 ℃ along with the furnace to complete upsetting and drawing deformation for 1 heating time, then returning to the furnace and preserving heat for 1-2 h, then completing primary upsetting and drawing deformation, wherein the upsetting pressing rate is 0.05s ^-1 ～0.04s ^-1 The upsetting deformation is between 35 and 45 percent;

step 4) heating the blank to 80-20 ℃ below the phase transformation point for upsetting and drawing deformation for 6-8 times, wherein the upsetting rate of each time is required to be 0.05s ^-1 ～0.04s ^-1 The deformation is between 30 and 50 percent, and the accumulated forging ratio is more than or equal to 3.3. The final forging temperature is more than or equal to 910℃；

Step 5) heating the blank to 60-40 ℃ below the beta transformation point for forming, wherein the deformation rate per firing is required to be 0.005 ^-1 ～0.05 ^-1 The pressing amount is between 30 and 40 percent to obtain a forging stock;

and 6) carrying out solid solution and aging heat treatment on the forged blank obtained in the step 5), wherein the solid solution heat treatment system is as follows: t is _β Keeping the temperature for 1 to 3 hours at the temperature of between 50 and 20 ℃, and carrying out air cooling or air cooling after discharging; the aging heat treatment comprises the following steps: keeping the temperature at 530-560 ℃ for 2-8 h, and then cooling in air.

The preferable scheme of the preparation process of the high-uniformity TC25G high-temperature titanium alloy large-size fine-grained structure blisk is that in the step 3), after upsetting is completed, the blank is returned to the furnace for temperature compensation for 1-3 hours, and then the drawing process is continuously completed.

The preferred scheme of the preparation process of the high-uniformity TC25G high-temperature titanium alloy large-size fine-grained structure blisk is that the forming mode adopted in the step 4) is an isothermal or near isothermal forming process; when the isothermal or near isothermal die forging forming process is adopted, the die is heated to 0-60 ℃ below the heating temperature of the blank, and the deformation rate is 0.005s ^-1 ～0.05s ^-1 。

The invention has the beneficial effects that:

1) The diameter of the blisk forge piece prepared by the method is 600 mm-1300 mm, the height of the blisk forge piece is 60 mm-120 mm, the structure uniformity of each part of the forge piece is uniform, and the performance is stable;

2) The tensile strength at room temperature of any part of the forging is not lower than 1100Mpa, the yield is not lower than 950Mpa, the elongation is not lower than 15%, and the face shrinkage is not lower than 25%; the elongation of the sample after being exposed for 100 hours at 550 ℃ is not less than 10 percent, and the surface shrinkage is not less than 20 percent; tensile strength of tensile property at 500 ℃ is not lower than 850MPa; the yield strength is not lower than 650MPa; the elongation is not less than 20 percent, and the surface shrinkage is not less than 40 percent; tensile strength at 550 ℃ is not lower than 750MPa, yield is not lower than 600MPa, elongation is not lower than 25.0%, and face shrinkage is not lower than 50%.

By adopting the process flow of the invention to forge, the size of the forge piece can be increased and the structure uniformity and performance of the forge piece can be improved on the premise of not increasing the process flow.

Drawings

FIG. 1 is a high magnification organization picture near the surface of a forging prepared in example 1;

FIG. 2 is a photograph of a high magnification microstructure of the center of the forging stock prepared in example 1;

FIG. 3 is a photograph of a high magnification structure near the surface of the forging produced in example 2;

FIG. 4 is a photograph of a high magnification microstructure of the center of the forging stock prepared in example 2;

FIG. 5 is a schematic representation of a die forging prepared in examples 3 and 4;

FIG. 6 is a high magnification microstructure picture of the rim of the die forged part prepared in example 3;

FIG. 7 is a high magnification organization picture of a spoke plate of the die forging prepared in example 3;

FIG. 8 is a high power texture picture of the die forging hub prepared in example 3;

FIG. 9 is a high power texture picture of the rim of the die forged part prepared in example 3;

FIG. 10 is a high magnification organization picture of a spoke plate of the die forging prepared in example 3;

FIG. 11 is a high magnification organization chart of the die forging hub prepared in example 3.

Detailed Description

Example 1:

the TC25G ingot used in the embodiment has the size of 600mm in diameter and 1300mm in length and comprises the following chemical components: al:6.51%, sn:1.93%, zr:3.58%, mo:3.91%, si:0.21%, W: 0.96% and a beta transus temperature of 985 ℃.

Step 1), heating an alloy ingot to 1150 ℃, preserving heat for 20 hours, discharging from a furnace, forging, and completing 1 upsetting, drawing and deformation; then performing remelting and heat preservation for 2 hours, and completing upsetting and drawing deformation for 1 time to obtain a blank; the deformation rate of each upsetting press is 0.1s ^-1 Performing single upsetting deformation of not less than 50%, and performing air cooling after forging to obtain a blank;

step 2) heating the blank obtained in the step 1) to 1005 ℃, and carrying out upsetting and drawing deformation for 1 firing time, wherein the upsetting pressing deformation is 52 percent, and the deformation rate is 0.1s ^-1 The forging ratio is 3.6, and water cooling is carried out after forging;

step 3) heating the blank to 840 ℃, preserving heat for 10h, then heating to 960 ℃ along with the furnace, carrying out upsetting and drawing deformation for 1 firing time, then carrying out reheating and drawing deformation for 2h, wherein the upsetting hold-down amount is 40%, and the deformation rate is 0.04s ^-1 Air cooling after forging;

step 4) heating the blank to 955 ℃, performing upsetting, drawing and deforming forging for 8 times of fire, wherein the upsetting deformation of each time is 37-40%, the cumulative forging ratio is 3.3-3.5, and air cooling is performed after forging;

step 5) blanking by a sawing machine according to the design size of the final forged piece, and forming the blank at 950 ℃, wherein the forming pressing deformation is 40%, and the deformation rate is 0.01s ^-1 Obtaining a forging stock;

step 6) carrying out solid solution and aging heat treatment on the forging stock, wherein the solid solution heat treatment system is as follows: 950. keeping the temperature for 3 hours, and cooling in air after discharging; the aging heat treatment comprises the following steps: keeping the temperature at 540 ℃ for 6h, and then cooling in air. And finally, polishing the surface to obtain the forged piece with the diameter of 1000mm and the height of 120 mm.

Example 2:

this example is a comparative example of example 1, and the ingot size, chemical composition, and β transus temperature selected were exactly the same as those of example 1.

In the embodiment, in the step 3, the forging stock is directly heated to 960 ℃ for upsetting and drawing deformation, and other steps are completely the same as those in the embodiment 1, so that the forging with the diameter of 1000mm and the height of 120mm is finally obtained.

The forging pieces of the embodiment 1 and the embodiment 2 are analyzed and compared in structure and mechanical property, the high power structure of the forging piece of the embodiment 1 is a two-state structure, the primary alpha content is about 20%, the primary beta crystal grains are fine and uniform in size, the primary alpha is uniformly distributed and does not obviously gather, and the structures of all positions are not obviously different (figures 1 and 2). The tensile strength of the forged piece at room temperature can reach more than 1100MPa, the tensile strength at 500 ℃ can reach more than 850MPa, the tensile strength at 550 ℃ can reach more than 780MPa, the forged piece has good plasticity, after the hot exposure at 550 ℃/100h, the tensile property of the forged piece at room temperature is not obviously reduced, and the thermal stability of the forged piece is good. The high power structure of the forging of the embodiment 2 is a two-state structure, the primary alpha content is about 21 percent, the distribution is not uniform, the original beta crystal grains are coarse, and the size is not uniform; (FIG. 3, FIG. 4). The tensile test result shows that the tensile strength of the forge piece at different positions has larger difference, and the overall strength is relatively lower.

TABLE 1 tensile Properties of the forgings of example 1

Table 2 thermal stability in example 1

TABLE 3 tensile Properties of the forgings of example 2

Table 4 thermal stability in example 2

Example 3:

the TC25G ingot used in the example has the size of 600mm in diameter and 1300mm in length and comprises the following chemical components: al:6.55%, sn:2.01%, zr:3.51%, mo:3.89%, si:0.19%, W: 0.96% and a beta transition temperature of 987 ℃.

Step 1), heating an alloy ingot to 1150 ℃, preserving heat for 20 hours, discharging from a furnace, forging, and completing 1 upsetting, drawing and deformation; and then performing remelting and heat preservation for 2 hours, and completing upsetting and drawing deformation for 1 time to obtain a blank. The deformation rate per upsetting is 0.1s ^-1 Single upsetting deformation is not less than 50%, and air cooling is carried out after forging to obtain a blank;

step 2) upsetting and drawing deformation are carried out on the blank obtained in the step 1) for 1 heating time at 1010 ℃, the upsetting pressing deformation is 52%, and the deformation rate is 0.1s ^-1 The forging ratio is 3.5, and water cooling is carried out after forging;

step 3) heating the blank to 840 ℃ and preserving heat for 8h, then heating the blank to 950 ℃ along with the furnace to carry out upsetting and drawing deformation for 1 firing time, then returning the blank to the furnace and preserving heat for 2h, then carrying out upsetting and drawing deformation once again, wherein the upsetting pressing deformation amount is 40%, the deformation rate is 0.05s < -1 >, and air cooling is carried out after forging;

step 4) heating the blank to 947 ℃, carrying out upsetting, drawing and deforming forging for 7 times, wherein the rough pressing deformation amount of each time is 40%, the deformation rate is 0.05s < -1 >, the cumulative forging ratio is 3.5-3.8, and air cooling is carried out after forging;

step 5) according to the design of the forge piece, adopting a sawing machine for blanking, adopting a near-isothermal die forging forming process, heating the die to 900 ℃, heating the forging stock to 950 ℃, and setting the deformation rate to 0.01s ^-1 Performing air cooling after forging to obtain a cake blank of the die forging, wherein the deformation is 40%;

and 6) performing solid solution and aging heat treatment on the forged blank, wherein the solid solution heat treatment system is as follows: 955. keeping the temperature for 2 hours, and cooling in air after discharging; the aging heat treatment comprises the following steps: keeping the temperature at 540 ℃ for 6h, and then cooling in air. And finally, polishing the surface to obtain a forging blank with the diameter of 1300mm and the height of 100 mm.

Example 4:

this example is a comparative example of example 3, and the ingot size, chemical composition, and β transus temperature selected were exactly the same as in example 3.

In the embodiment, in the step 3, the forging stock is directly heated to 960 ℃ for upsetting, drawing and deforming, and other steps are completely the same as those in the embodiment 3, so that the forging with the diameter of 1300mm and the height of 100mm is finally obtained.

FIG. 5 is a schematic view of forgings of embodiments 3 and 4. The forgings of example 3 and example 4 were compared for structural and mechanical property analysis. The high power structure of the forging of the embodiment 3 is a typical double-state structure, and the primary alpha content is about 25 percent (figures 6-8); the tensile strength of the forge piece at room temperature can reach more than 1100MPa, the tensile strength at 500 ℃ can reach more than 850MPa, the tensile strength at 550 ℃ can reach more than 770MPa, the forge piece has good plasticity, and the difference of the tensile properties of the forge piece at different positions is small. After the hot exposure at 550 ℃/100h, the room-temperature tensile property of the forge piece is not obviously reduced, and the thermal stability of the forge piece is good. The high power structure of the forging piece in the embodiment 4 is a two-state structure, the primary alpha content is about 25%, the distribution is not uniform, the original beta grains are coarse, and the microstructure difference of different positions of the forging piece is obvious (fig. 9-10). The structural difference results in poor consistency of mechanical properties of the forged piece at different positions, and compared with embodiment 3, the overall tensile strength of the forged piece is low.

TABLE 5 tensile Properties of the forgings of example 3

Table 6 thermal stability in example 3

TABLE 7 tensile Properties of the forgings of example 4

Table 8 thermal stability in example 3

The above embodiments are merely illustrative of the technical ideas and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. A preparation process of a high-uniformity TC25G high-temperature titanium alloy large-size fine-grain blisk is characterized by comprising the following specific steps:

step 1) firstly heating an alloy ingot to 1100-1200 ℃, preserving heat for 15-35 h, discharging from a furnace and forging to finish 1-time upsetting and drawing deformation; then the blank is returned to the furnace and is kept warm for 1 to 2 hours, and then 1 upsetting and drawing deformation are finished to obtain the blank, and the pressing deformation rate of each upsetting is 0.2s ^-1 ～0.08s ^-1 Performing single upsetting deformation of not less than 50%, and performing air cooling after forging to obtain a blank;

step 2) performing 1-time hot upsetting and drawing deformation on the blank obtained in the step 1) at the temperature of 10-30 ℃ above the beta transformation point, wherein the pressing deformation rate under upsetting is 0.2s ^-1 ～0.08s ^-1 The upsetting deformation is more than or equal to 50 percent, and water cooling is carried out after forging;

step 3) heating the blank to 800-840 ℃, preserving heat for 6-10 h, heating to 920-960 ℃ along with the furnace to complete upsetting and drawing deformation for 1 heating time, then returning to the furnace and preserving heat for 1-2 h, then completing upsetting and drawing deformation for one time, wherein the upsetting pressing rate is 0.05s ^-1 ～0.04s ^-1 The upsetting deformation is between 35 and 45 percent;

step 4) heating the blank to 80-20 ℃ below the phase change point for upsetting and drawing deformation for 6-8 times, wherein the upsetting rate of each time is required to be 0.05s ^-1 ～0.04s ^-1 The deformation is between 30 and 50 percent, the accumulated forging ratio is more than or equal to 3.3, and the finish forging temperature is more than or equal to 910 ℃;

step 5) heating the blank to 60-40 ℃ below the beta transformation point for forming, wherein the deformation rate per firing is required to be 0.005s ^-1 ～0.05s ^-1 The pressing amount is between 30 and 40 percent to obtain a forging stock;

2. The process for preparing the high-uniformity TC25G high-temperature titanium alloy large-size fine-grain blisk as claimed in claim 1, wherein the process comprises the following steps: the blisk forge piece with the diameter of 600mm to 1300mm and the height of 60mm to 120mm is prepared by the process.

3. The process for preparing the high-uniformity TC25G high-temperature titanium alloy large-size fine-grain blisk as claimed in claim 1, wherein: in the step 3), the blank is returned to the furnace for temperature compensation for 1 to 3 hours after upsetting is finished, and then the drawing process is continuously finished.

4. The process for preparing the high-uniformity TC25G high-temperature titanium alloy large-size fine-grain blisk as claimed in claim 1, wherein: the forming mode adopted in the step 4) is an isothermal or near isothermal forming process; when the isothermal or near isothermal die forging forming process is adopted, the die is heated to 0-60 ℃ below the blank heating temperature, and the deformation rate is 0.005s ^-1 ～0.05s ^-1 。