Method for controlling shearing and spinning residual stress of titanium alloy structural part

Abstract

The invention discloses a method for controlling shearing and spinning residual stress of a titanium alloy structural part, and belongs to the field of material processing. And the residual stress is controlled by adopting a spinning, solid solution and aging method. In the spinning machining process, the first-pass feeding ratio is 0.8-1.2, the second-pass feeding ratio is 0.4-0.6, and the solution treatment system is that the temperature range of the solution treatment is increased to 1000 DEG C along with a furnace, heat preservation is conducted for 2 h, and then the furnace is cooled to the room temperature; and the aging treatment system is that the temperature is increased to 650 DEG C along with the furnace, heat preservation is conducted for 4 h, then furnace cooling is conducted to 400 DEG C, and then air cooling is conducted. The problem that the residual stress is too large in the titanium alloy component spinning machining process is solved, control over the titanium alloy structure shearing spinning residual stress is achieved, cost is saved, the product machining period is shortened, and a foundation is laid for accelerating implementation of engineering application.

Description

Technical Field

[0001] The present invention belongs to the technical field of material processing, and relates to a method for controlling the residual stress of a titanium alloy structural part during shear spinning. Background Art

[0002] Titanium and its alloys are widely used in the aerospace field due to their high specific strength, corrosion resistance, fatigue resistance, and good high-temperature performance. Since the shear spinning process is a continuous and locally loaded deformation process, due to the non-uniformity of the strain field and temperature field, the titanium alloy structural part will undergo non-uniform deformation during the spinning process, generating residual stress inside the material, and causing stress corrosion and even cracking during subsequent use. If the residual stress inside the processed material is relatively high, it can also cause micro-deformation of the component, affecting the accuracy of the component. The existing methods for controlling residual stress are all long-term high-vacuum aging after processing, and it is impossible to control the residual stress from the processing process. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to propose a method for controlling the residual stress of a titanium alloy structural part during shear spinning, which replaces the traditional aging method, saves costs, and reduces the consumption of manpower and material resources.

[0004] To achieve the above purpose, the technical solution of the present invention is realized as follows: 1. A method for controlling the residual stress of a titanium alloy structural part during shear spinning, characterized by the following steps: Step 1: Prepare the blank, debug the spinning equipment, install and calibrate the spinning die, and compile the numerical control processing program; Step 2: Perform the first-pass spinning process with a rotational speed S of 30 r / min and a feed rate F of 30 mm / min; Step 3: Perform the second-pass spinning process with a rotational speed S of 30 r / min and a feed rate F of 15 mm / min; Step 4: Treat the surface of the spun titanium alloy structural part, and there should be no impurities such as oil stains; Step 5: Perform solution treatment at 1000 °C for 2 h; Step 6: Perform aging treatment on the titanium alloy structural part processed in Step 5 at 650 °C for 4 h.

[0005] 2. According to the method for controlling the residual stress of a titanium alloy structural part during shear spinning described in Claim 1, it is characterized in that: in Step 1, a numerically controlled open spinning machine is used for the spinning equipment, the runout of the die cone surface of the spinning die is not greater than 0.1 mm, the program content includes the spinning gap, feed ratio, etc., and a lubricant is applied to the surface of the component before processing.

[0006] 3. A method for controlling the residual stress of a titanium alloy structural part by shear spinning, according to claim 1, characterized in that: in step 2, the feed ratio of the spinning process is 0.8 - 1.2, and surface lubricant is replenished in a timely manner during the spinning process.

[0007] 4. A method for controlling the residual stress of a titanium alloy structural part by shear spinning, according to claim 1, characterized in that: in step 3, the feed ratio of the spinning process is 0.4 - 0.6, and surface lubricant is replenished in a timely manner during the spinning process.

[0008] 5. A method for controlling the residual stress of a titanium alloy structural part by shear spinning, according to claim 1, characterized in that: in step 4, the surface treatment of the part is to wipe the surface with alcohol, and the purpose is to remove the lubricant during the spinning process.

[0009] 6. A method for controlling the residual stress of a titanium alloy structural part by shear spinning, according to claim 1, characterized in that: in step 5, the solution treatment temperature range is 950 - 1050 °C, heating up with the furnace, holding for 2 h and then cooling to room temperature in the furnace.

[0010] 7. A method for controlling the residual stress of a titanium alloy structural part by shear spinning, according to claim 1, characterized in that: in step 6, the titanium alloy component after solution treatment in step 5 is put into a heat treatment furnace for aging treatment, the aging temperature range is 600 - 700 °C, heating up with the furnace, holding for 4 h and then cooling to 400 °C with the furnace, and then air cooling.

[0011] Advantages and beneficial effects of the present invention compared with the prior art: A method for controlling the residual stress of a titanium alloy structural part by shear spinning of the present invention creates a method that adjusts the spinning process parameters to control the residual stress from the beginning of the spinning process, and combines with solution treatment and aging after processing to control the residual stress, solves the problem of excessive residual stress during the spinning process of titanium alloy components, and realizes the control of the residual stress of titanium alloy structural shear spinning through the optimization of spinning process parameters, solution process and aging process. This method greatly saves costs and shortens the product processing cycle, laying a foundation for accelerating the realization of engineering applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 The first pass of spinning processing; Figure 2 The second pass of spinning processing; Figure 3 Solution treatment system; Figure 4 For the aging treatment system. EMBODIMENTS

[0013] The following takes a titanium alloy cylindrical structural part as a specific embodiment, and further elaborates on the present invention in conjunction with the attached drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention, but they do not constitute a limitation to the present invention.

[0014] Step 1: Prepare the blank. The spinning equipment uses a numerically controlled open spinning machine. Debug the spinning equipment, install the spinning die and calibrate the spinning die. The runout of the die conical surface of the spinning die is not more than 0.1 mm, and compile the numerically controlled processing program; the program content includes the spinning gap, feed ratio, etc. Apply a lubricant to the surface of the cylindrical part before spinning.

[0015] Step 2: The first-pass spinning process. As shown in the attachment Figure 1 shown, the spinning gap is 13.5 mm, the rotational speed S is 30 r / min, the feed F is 30 mm / min, and the feed ratio for spinning is between 0.8 and 1.2. If it is found that the surface lubricant is missing during the spinning process, it should be replenished in time.

[0016] Step 3: The second-pass spinning process. As shown in the attachment Figure 2 shown, the spinning gap is 6.0 mm, the rotational speed S is 30 r / min, the feed F is 15 mm / min, and the feed ratio for spinning is between 0.4 and 0.6. Timely replenish the surface lubricant during the spinning process.

[0017] Step 4: Treat the surface of the spun titanium alloy cylindrical part. There are residues and lubricants on the surface of the spun cylindrical part. Wipe the surface of the cylindrical part with alcohol, and only after removing the lubricant can solution treatment be carried out.

[0018] Step 5: Carry out solution treatment. The solution treatment system is as shown in the attachment Figure 3 shown. Heat up to 1000 °C with the furnace, hold for 2 h, and then cool to room temperature in the furnace. In actual operation, the temperature range can be 950 - 1050 °C.

[0019] Step 6: Put the titanium alloy cylindrical part after solution treatment in step 5 into a heat treatment furnace for aging treatment. The aging treatment system is as shown in the attachment Figure 4 shown. Heat up to 650 °C with the furnace, hold for 4 h, then cool to 400 °C with the furnace, and then air-cool. In actual operation, the temperature range for aging is 600 - 700 °C.

[0020] Detect the residual stress of the titanium alloy cylindrical part in each process according to the above method. After detection, the original residual stress of the sample is 185 MPa. After one-pass spinning, two-pass spinning, solution treatment and aging, its residual stresses are 163 MPa, 132 MPa, 80 MPa, and 20 MPa. Therefore, the pore control of residual stress can be achieved by the method of the present invention.

Claims

1. A method for controlling the residual stress of a titanium alloy structural part during shear spinning, characterized by the following steps: Step 1: Prepare the blank, debug the spinning equipment, install and calibrate the spinning die, and compile the numerical control processing program; Step 2: Perform the first-pass spinning process with a rotational speed S of 30 r / min and a feed rate F of 30 mm / min; Step 3: Perform the second-pass spinning process with a rotational speed S of 30 r / min and a feed rate F of 15 mm / min; Step 4: Treat the surface of the spun titanium alloy structural part, ensuring there are no impurities such as oil stains; Step 5: Conduct solution treatment at 1000°C for 2 h; Step 6: Age the titanium alloy structural part processed in Step 5 at 650°C for 4 h.

2. The method for controlling the residual stress of a titanium alloy structural part during shear spinning according to claim 1, characterized in that: In Step 1, a numerically controlled open spinning machine is used for the spinning equipment. The runout of the die conical surface of the spinning die is not more than 0.1 mm. The program content includes spinning clearance, feed ratio, etc. Apply a lubricant to the surface of the component before processing.

3. The method for controlling the residual stress of a titanium alloy structural part during shear spinning according to claim 1, characterized in that: In Step 2, the feed ratio for the spinning process is 0.8 - 1.2, and replenish the surface lubricant in a timely manner during the spinning process.

4. The method for controlling the residual stress of a titanium alloy structural part during shear spinning according to claim 1, characterized in that: In Step 3, the feed ratio for the spinning process is 0.4 - 0.6, and replenish the surface lubricant in a timely manner during the spinning process.

5. The method for controlling the residual stress of a titanium alloy structural part during shear spinning according to claim 1, characterized in that: In Step 4, the surface treatment of the part is to wipe the surface with alcohol, aiming to remove the lubricant during the spinning process.

6. The method for controlling the residual stress of a titanium alloy structural part during shear spinning according to claim 1, characterized in that: In Step 5, the solution treatment temperature range is 950 - 1050°C. Heat up the furnace with the component, hold for 2 h, and then cool in the furnace to room temperature.

7. The method for controlling the residual stress of a titanium alloy structural part during shear spinning according to claim 1, characterized in that: In Step 6, put the titanium alloy component solution-treated in Step 5 into a heat treatment furnace for aging treatment. The aging temperature range is 600 - 700°C. Heat up the furnace with the component, hold for 4 h, then cool in the furnace to 400°C, and then air-cool.

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