Low-stress forming method for titanium alloy special-shaped ring piece
By designing the feed speed curve in the uniform expansion mode during the low-stress forming process of titanium alloy special-shaped ring parts, and combining forging and swelling techniques, the problem of unscientific determination of feed speed in the existing technology is solved, and the good forming quality and production efficiency of the ring parts are improved.
Patent Information
- Application Number
- CN202311839697.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-28
- Publication Date
- 2025-07-01
AI Technical Summary
In the low-stress forming process of titanium alloy special-shaped rings in the prior art, the determination of feed speed lacks scientific basis, resulting in unstable forming quality of the ring, large dimensional errors, and a large amount of subsequent processing is required, which increases production cost and time.
After modification and blank making, the feed speed curve in a uniform expansion mode is designed, and the rolling and forming is performed using a ring rolling mill, and the expansion is performed in a small deformation amount to eliminate residual stress.
The good tissue performance and rolling line integrity of titanium alloy special-shaped ring parts are achieved, which reduces subsequent processing needs and improves forming quality and production efficiency.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to a rolling forming method for ring parts, in particular to a low-stress forming method for titanium alloy special-shaped ring parts. Background Art
[0002] Low-stress forming refers to obtaining a blank with excellent tissue properties through forging and blanking, and then obtaining a forging with relatively low residual stress after rolling forming. During the low-stress forming process of ring parts, the most critical control parameter is the feed rate. Whether the feed rate is reasonable is not only a prerequisite for realizing the stable rolling of ring parts, but also directly affects the diameter growth rate and final forming quality of ring parts.
[0003] At present, in actual production practice, the determination method of the feed rate mostly relies on process debugging and the experience of operators. The design method is simple and rough, lacking scientific basis, resulting in a large difference between the size of the rolled ring forging and the size of the final ring part product. A large number of subsequent machining processes such as cutting are required to obtain the ring-shaped part with the final size. This not only wastes materials, prolongs the production cycle, increases the production cost, but also makes the performance of the ring-shaped part unable to be reliably guaranteed. Summary of the Invention
[0004] The technical problem to be solved by the present invention is to provide a design method for a reasonable feed rate to realize the low-stress forming of titanium alloy special-shaped ring parts and obtain titanium alloy special-shaped ring parts with good tissue properties and complete rolling lines.
[0005] To solve the above technical problem, the low-stress forming method for titanium alloy special-shaped ring parts of the present invention includes the following steps:
[0006] Forging the titanium alloy bar cut according to specifications at a temperature 30°C to 80°C above the phase transition point with a deformation amount of 60% to 70%;
[0007] Heating the blank to a temperature 20°C to 50°C above the phase transition point, and obtaining a titanium alloy pre-rolled ring blank after upsetting and punching;
[0008] Design the feed rate for low-stress rolling:
[0009] Set that during low-stress rolling, the outer diameter of the ring part is R and the feed is Δ, and both R and Δ are functions of time t;
[0010] From the change of the feed Δ with time t, it can be known that: Where v(t) is the feed rate;
[0011] Then set that in the mode of uniform expansion of the ring part, the feed per revolution of the ring part is Δ1, then: Thus After taking the derivative of both sides, we get:
[0012] Since the feed amount of the ring blank at the start of rolling is △0 = 0 and the feed amount at the end of rolling is △ t = D0 - D1; where D0 and D1 are the maximum thicknesses of the blank and the final ring respectively;
[0013] According to the feed amounts at the start and end of rolling, the feed curve in the uniform expansion mode can be obtained;
[0014] After heating the pre-rolled ring blank to 250°C - 300°C, it is loaded into the ring rolling mill, and the ring is roll-formed according to the above feed curve;
[0015] The formed titanium alloy special-shaped ring is placed on a bulging machine for bulging with a small deformation amount to eliminate residual stress.
[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0017] The low-stress forming method of the titanium alloy special-shaped ring described in the present invention obtains a blank with excellent tissue properties through forging and blank making. Through roll forming and small-deformation bulging, on the one hand, the integrity of the rolling lines of the ring is ensured, and on the other hand, the excellent tissue properties of the blank are inherited. The present invention makes the ring easier to form by designing the feed method in the uniform expansion mode.
[0018] The uniform expansion mode requires that the outer diameter expansion speed of the ring remains unchanged at each moment during the forming process by adjusting the feed speed in real time; the constant feed amount mode requires that the feed amount of the core roll remains unchanged during each revolution of the ring by adjusting the feed speed. When the linear speed of the driving roll is constant, the time required for the ring to make one revolution depends on the outer diameter of the ring. Specific Embodiments
[0019] Implementing the low-stress forming method of the titanium alloy special-shaped ring described in the present invention requires providing equipment such as a forging heating furnace, a press, a ring rolling mill, and a manipulator. The following takes the titanium alloy with the grade of TC4 as an example to detail the specific implementation of this method:
[0020] The main chemical element contents (by weight percentage) of this alloy are: Al content 5.5% - 6.8%, V content 3.5% - 4.5%, Fe content ≤ 0.30%, C content ≤ 0.10%, N content ≤ 0.05%, H content ≤ 0.015%, O content ≤ 0.20%, other elements single ≤ 0.10% and the total ≤ 0.40%, and the balance is Ti.
[0021] The steps of this method are as follows:
[0022] The titanium alloy bars cut according to specifications are forged at a temperature 30°C to 80°C above the phase transformation point with a deformation amount of 60% to 70%.
[0023] The billet is heated to 20°C to 50°C above the phase transformation point, and after upsetting and punching, a pre-rolled titanium alloy ring blank is obtained.
[0024] Design the feed rate of low-stress rolling:
[0025] When setting low-stress rolling, the outer diameter of the ring is R and the feed is Δ. Both R and Δ are functions of time t.
[0026] From the variation of the feed Δ with time t, it can be seen that: In the formula, v(t) is the feed rate.
[0027] Then, when setting the ring to expand at a uniform speed, the feed per revolution of the ring is Δ1, so: Thus After taking the derivative of both sides, we get:
[0028] Since the feed at the start of rolling of the ring is Δ0 = 0, and the feed at the end of rolling is Δ t = D0 - D1; where D0 and D1 are the maximum thicknesses of the billet and the final ring respectively.
[0029] According to the feed at the start and end of rolling, the feed curve in the uniform expansion mode can be obtained.
[0030] After heating the pre-rolled ring blank to 250°C to 300°C, it is loaded into a ring rolling mill, and the ring is formed with low stress according to the above feed curve.
[0031] The formed titanium alloy special-shaped ring is placed on a bulging machine for bulging with a small deformation amount to eliminate residual stress.
Claims
1. A method for low-stress forming of titanium alloy special-shaped ring parts, characterized in that, It includes the following steps: Redo forging the titanium alloy bar stock cut according to specifications at a temperature 30°C to 80°C above the phase transformation point with a deformation amount of 60% to 70%; Heat the blank to a temperature 20°C to 50°C above the phase transformation point, and obtain a pre-rolled titanium alloy ring blank after upsetting and punching; Design the feed rate of low-stress rolling: When setting low-stress rolling, the outer diameter of the ring is R and the feed is Δ, and both R and Δ are functions of time t; It can be seen from the variation of the feed rate △ with time t that: where v(t) is the feed speed; If it is set again that under the mode of uniform expansion of the ring part, the feed per revolution of the ring part is △1, then: Thus After taking the derivative of both sides, we get: Since the feed at the start of ring rolling is △0 = 0, and the feed at the end of rolling is △ t = D0 - D1; Among them, D0 and D1 are the maximum thicknesses of the blank and the final ring respectively; According to the feed at the start and end of rolling, the feed curve in the uniform expansion mode can be obtained; After heating the pre-rolled ring blank to 250°C to 300°C, load it into the ring rolling mill and roll the ring according to the above feed curve; Put the formed titanium alloy special-shaped ring into a bulging machine for bulging with a small deformation amount to eliminate residual stress.