Control method of β deformation texture of TC18 titanium alloy die forgings

Abstract

The present invention relates to a method for controlling the β deformation texture of a TC18 titanium alloy die forging, and belongs to the technical field of titanium alloy parts manufacturing. The method for controlling the β deformation texture of a TC18 titanium alloy die forging comprises: a. <100> and β <111> Substituting the volume fraction of the deformation texture into formulas (1) and (2) to calculate the quasi-β forging strain distribution, we obtain ε 需求1 , ε 需求2 ; V 100 =75.1ε 需求1 ‑12.1#(1);V 111 =52.8ε 需求2 +3.15#(2); wherein, the ε 需求1 , ε 需求2 is the quasi-β forging strain distribution of TC18 titanium alloy; V 100 The required β <100> Deformation texture volume fraction; V 111 The required β <111> The present invention accurately controls the volume fraction of deformation texture of TC18 titanium alloy die forgings. <100> and β <111> Deformation texture guides the shape and process design of forgings.

Description

Technical Field

[0001] The invention relates to a method for controlling the beta deformation texture of a TC18 titanium alloy die forging, and belongs to the technical field of titanium alloy part manufacturing. Background Art

[0002] TC18 titanium alloy is a high-strength and high-toughness near-β titanium alloy widely used in the aviation industry. Due to its excellent damage tolerance, it is widely used in the manufacture of aircraft structural parts. However, due to the complex shape of TC18 titanium alloy aircraft structural parts, the strain distribution during the β forging process is often uneven, resulting in strong β <100> and β <111> Deformation texture, this deformation texture will greatly reduce the strength of the forging and produce anisotropy. Therefore, how to accurately control the strain distribution of TC18 titanium alloy die forgings during β forging to avoid serious β <100> and β <111> Deformation texture, thereby achieving control of forging strength, is of great significance to the engineering manufacturing and safe service of TC18 titanium alloy die forgings.

[0003] There is currently no precise control of the β <100> and β <111> Deformation texture method. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for controlling the β deformation texture of a TC18 titanium alloy die forging.

[0005] To achieve the purpose of the present invention, the method for controlling the β deformation texture of the TC18 titanium alloy die forging comprises:

[0006] a. The required β <100> and β <111> Substituting the volume fraction of the deformation texture into formulas (1) and (2) to calculate the quasi-β forging strain distribution, we obtain ε 需求1 , ε 需求2 ;

[0007] V 100 =75.1ε 需求1 -12.1 #(1);

[0008] V 111 =52.8ε 需求2 +3.15 #(2);

[0009] Among them, the ε 需求1 , ε 需求2 is the quasi-β forging strain distribution of TC18 titanium alloy; V 100 The required β <100> Deformation texture volume fraction; V 111 The required β <111> deformation texture volume fraction;

[0010] b. Then use numerical simulation technology to design forgings and adjust the strain range to be less than or equal to ε 需求1 and ε 需求2 within the range.

[0011] In one embodiment, the method further comprises substituting the desired tensile strength σ into equations (3) and (4) to calculate V 100 and V 111 :

[0012] σ=1111.1-1.18V 100 #(3);

[0013] σ=1138.6-1.99V 111 #(4).

[0014] In one embodiment, the method is applicable to 需求1 , ε 需求2 The range is 0.1~1.0.

[0015] In a specific embodiment, the TC18 titanium alloy die forging is a TC18 titanium alloy die forging that is quasi-β forged and double annealed.

[0016] In a specific embodiment, the double annealing process includes: keeping the temperature at 830-850°C for 1-4 hours, cooling to 730-750°C with the furnace, keeping the temperature for 1-4 hours, and air cooling after leaving the furnace; and then keeping the temperature at 600-620°C again.

[0017] The tensile strength σ is the strength of a TC18 titanium alloy die forging after aging at 600-620°C.

[0018] Beneficial effects:

[0019] 1. This invention accurately establishes the TC18 titanium alloy β <100> and β <111> The mathematical relationship between the volume fraction of deformation texture and the strain distribution of quasi-β forging of forgings can be calculated according to the volume fraction control requirements of the deformation texture of forgings, and the strain distribution range of quasi-β forging can be accurately controlled. <100> and β <111> Deformation texture guides the shape and process design of forgings.

[0020] 2. The present invention also accurately establishes the TC18 titanium alloy β <100> and β <111> The mathematical relationship between deformation texture and tensile strength of forgings can accurately calculate the volume fraction control range of the required deformation texture according to the tensile strength requirements of TC18 titanium alloy die forgings. Then, based on the volume fraction of the required deformation texture of the forgings, the strain distribution range of quasi-β forging can be calculated to accurately control the β forging process of TC18 titanium alloy die forgings. <100> and β <111> Deformation texture guides the shape and process design of forgings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a cross-sectional view of the TC18 titanium alloy forging of Example 1.

[0022] Figure 2 This is the EBSD grain distribution diagram of the TC18 titanium alloy variable-section forging in Example 1 at the position of maximum strain.

[0023] Figure 3 This is the EBSD pole figure of the maximum strain position of the TC18 titanium alloy variable cross-section forging in Example 1.

[0024] Figure 4 is V in Example 1 100 Calculation results.

[0025] Figure 5 is V in Example 1 111 Calculation results.

[0026] Figure 6 This is a cross-sectional view of the TC18 titanium alloy forging of Example 2. DETAILED DESCRIPTION

[0027] To achieve the purpose of the present invention, the method for controlling the β deformation texture of the TC18 titanium alloy die forging comprises:

[0028] a. The required β <100> and β <111> Substituting the volume fraction of the deformation texture into formulas (1) and (2) to calculate the quasi-β forging strain distribution, we obtain ε 需求1 , ε 需求2 ;

[0029] V 100 =75.1ε 需求1 -12.1 #(1);

[0030] V 111 =52.8ε 需求2 +3.15 #(2);

[0031] Among them, the ε 需求1 , ε 需求2 is the quasi-β forging strain distribution of TC18 titanium alloy; V 100The required β <100> Deformation texture volume fraction; V 111 The required β <111> deformation texture volume fraction;

[0032] b. Then use numerical simulation technology to design forgings and adjust the strain range to be less than or equal to ε 需求1 and ε 需求2 within the range.

[0033] In one embodiment, the method further comprises substituting the desired tensile strength σ into equations (3) and (4) to calculate V 100 and V 111 :

[0034] σ=1111.1-1.18V 100 #(3);

[0035] σ=1138.6-1.99V 111 #(4).

[0036] In one embodiment, the method is applicable to 需求1 , ε 需求2 The range is 0.1~1.0.

[0037] In a specific embodiment, the TC18 titanium alloy die forging is a TC18 titanium alloy die forging that is quasi-β forged and double annealed.

[0038] In a specific embodiment, the double annealing process includes: keeping the temperature at 830-850°C for 1-4 hours, cooling to 730-750°C with the furnace, keeping the temperature for 1-4 hours, and air cooling after leaving the furnace; and then keeping the temperature at 600-620°C again.

[0039] The tensile strength σ is the strength of a TC18 titanium alloy die forging after aging at 600-620°C.

[0040] The specific embodiments of the present invention are further described below in conjunction with examples, but the present invention is not limited to the scope of the examples.

[0041] Example 1

[0042] A TC18 titanium alloy variable cross-section forging after quasi-β forging and double annealing requires the tensile strength of all positions to be greater than 1050 MPa. Figure 1 As shown. According to formula (3) and (4), calculate V 100 and V 111 Volume fraction of texture:

[0043] V 100 :(1111.1-1050) / 1.18=51.7

[0044] V 111 :(1138.6-1050) / 1.99=44.2

[0045] According to formulas (1) and (2), the strain distribution range is calculated as follows:

[0046] ε 需求1 :(51.7+12.1) / 75.1=0.85

[0047] ε 需求2 :(44.2-3.15) / 52.8=0.77

[0048] Numerical simulation technology is used to design forgings and the maximum strain is controlled within the range of 0.1≤ε≤0.77.

[0049] According to the numerical simulation results, the mold was designed, and the TC18 titanium alloy was subjected to quasi-β forging and double annealing heat treatment to obtain the final product.

[0050] The EBSD texture analysis and tensile test were performed on the maximum strain position of the final TC18 titanium alloy variable cross-section forging, and the statistical results are shown in Table 1. Among them, the EBSD grain distribution diagram is shown in Figure 2 As shown, the polar graph is Figure 3 As shown, V 100 The calculation results are as follows Figure 4 As shown, V 111 The calculation results are as follows Figure 5 The results show that the tensile strength at the maximum strain position is greater than 1050MPa, and V in the product is finally detected. 100 and V 111 The volume fractions of the textures are 19.4 and 32.4, respectively, which are consistent with the calculation results.

[0051] Table 1

[0052] Tensile strength / MPa Yield strength / MPa <![CDATA[V 100 ]]> <![CDATA[V 111 ]]> 1062 980 19.4％ 32.4％

[0053] Example 2

[0054] A TC18 titanium alloy variable cross-section forging after quasi-β forging and double annealing requires the tensile strength of all positions to be greater than 1080 MPa. Figure 6 As shown. According to formula (3) and (4), calculate V 100 and V 111 Volume fraction of texture:

[0055] V 100 :(1111.1-1080) / 1.18=26.4

[0056] V 111:(1138.6-1080) / 1.99=29.4

[0057] According to formulas (1) and (2), the strain distribution range is calculated as follows:

[0058] ε 需求1 :(26.4+12.1) / 75.1=0.51

[0059] ε 需求2 :(29.4-3.15) / 52.8=0.50

[0060] Numerical simulation technology is used to design forgings and the maximum strain is controlled within the range of 0.1≤ε≤0.50.

[0061] According to the numerical simulation results, the mold was designed, and the TC18 titanium alloy was subjected to quasi-β forging and double annealing heat treatment to obtain the final product.

[0062] The EBSD texture analysis and tensile test were performed on the maximum strain position of the final TC18 titanium alloy variable cross-section forging. The statistical results are shown in Table 2. The results show that the tensile strength at the maximum strain position is greater than 1050 MPa, and V in the product was finally detected. 100 and V 111 The volume fractions of the textures are 16.2 and 25.1, respectively, which are consistent with the calculation results.

[0063] Table 2

[0064] Tensile strength / MPa Yield strength / MPa <![CDATA[V 100 ]]> <![CDATA[V 111 ]]> 1100 1011 16.2％ 25.1％ .

Claims

1. A method for controlling the β deformation texture of TC18 titanium alloy die forgings, characterized in that: The method comprises: a. The required β <100> and β <111> Substituting the volume fraction of the deformation texture into formulas (1) and (2) to calculate the quasi-β forging strain distribution, we obtain ɛ 需求1 、ɛ 需求2 ; V 100 =75.1ɛ 需求1 -12.1 Formula (1); V 111 =52.8ɛ 需求2 +3.15 Formula (2); Among them, the 需求1 、ɛ 需求2 is the quasi-β forging strain distribution of TC18 titanium alloy; V 100 The required β <100> deformation texture volume fraction; V 111 The required β <111> deformation texture volume fraction; b. Then use numerical simulation technology to design forgings and adjust the strain range to be less than or equal to ɛ 需求1 andɛ 需求2 within the range.

2. The method for controlling β deformation texture of TC18 titanium alloy die forgings according to claim 1, characterized in that: The method further comprises substituting the required tensile strength σ into equations (3) and (4) to calculate V 100 and V 111 : σ=1111.1-1.18 V 100 Formula (3): σ=1138.6-1.99 V 111 Formula (4).

3. The method for controlling β deformation texture of TC18 titanium alloy die forgings according to claim 1 or 2, characterized in that: The method is applicable to ɛ 需求1 、ɛ 需求2 The range is 0.1~1.

0.

4. The method for controlling β deformation texture of TC18 titanium alloy die forgings according to claim 1 or 2, characterized in that: The TC18 titanium alloy die forging is a TC18 titanium alloy die forging that is quasi-β forged and double annealed.

5. The method for controlling β deformation texture of TC18 titanium alloy die forgings according to claim 4, characterized in that: The double annealing process includes: keeping the temperature at 830-850° C. for 1-4 hours, cooling the furnace to 730-750° C. for 1-4 hours, taking the furnace out of the furnace and air cooling; and then keeping the temperature at 600-620° C. again.

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