Near-isothermal radial forging method for titanium alloy long-shaft reducing part and product

Abstract

According to the near-isothermal radial forging method and product for the titanium alloy long-axis variable-diameter part, the forging temperature can be effectively controlled in the forming process of the long-axis variable-diameter part, near-isothermal forging is achieved, and therefore the structure uniformity and performance stability of the product are remarkably improved; the problems of over-temperature, uneven temperature distribution and the like caused by poor thermal conductivity of the titanium alloy can be solved, and the forming quality and performance of the product under the high-temperature forging condition are ensured. The method comprises the following steps: (1) heating a part bar billet to 20-60 DEG C lower than T beta, and preserving heat; (2) after heat preservation is completed, radial forging is used, and the bar billet is forged and formed; wherein in the step (2), the downward pressing amount of each time is controlled, the setting of the deformation amount in the whole forging process follows the principle that the deformation amount is firstly small, then large and finally small again, and a one-way feeding forging technology is adopted.

Description

Technical Field

[0001] The present invention relates to the technical field of nonferrous metal processing, and in particular to a near-isothermal radial forging method for titanium alloy long shaft-type variable-diameter parts, and products manufactured according to the near-isothermal radial forging method for titanium alloy long shaft-type variable-diameter parts. Background Art

[0002] The forming principle of radial forging technology is to forge the blank with small deformation and high frequency through four hammers evenly distributed along the axial direction of the blank. The material maintains spiral feed motion during the forging process, and finally realizes the blank forming by point and surface. This technology is particularly suitable for the forming of long shaft products due to its deformation characteristics. Due to the high forging frequency, the forging heat generated also increases. However, the thermal conductivity of titanium alloy is relatively poor, which leads to the problem of excessive temperature rise and uneven temperature distribution during the forging process. These problems not only affect the forming quality of the product, but also may have an adverse effect on the microstructure and performance of the product. Therefore, solving these temperature control problems is crucial to improving the overall performance of titanium alloy products. The Chinese invention patent with publication number CN109877269A discloses a temperature control method for radial precision forging of titanium and titanium alloy bars, the steps of which include: heating the blank, using a radial precision forging machine to forge the heated blank on one side, and returning to the starting point after each forging pass. The above technology only controls the temperature rise of the material through unilateral forging and is only applicable to bar forming. It does not involve the design of the deformation amount of each pass and is not applicable to the forming of variable diameter parts, and needs to be further improved. Summary of the invention

[0003] In order to overcome the defects of the prior art, the technical problem to be solved by the present invention is to provide a near-isothermal radial forging method for titanium alloy long shaft variable diameter parts, which can effectively control the forging temperature during the forming process of long shaft variable diameter parts and realize near-isothermal forging, thereby significantly improving the organizational uniformity and performance stability of the product, and can overcome the problems of over-temperature and uneven temperature distribution caused by the poor thermal conductivity of titanium alloy, thereby ensuring the forming quality and performance of the product under high temperature forging conditions.

[0004] The technical solution of the present invention is: the near-isothermal radial forging method for titanium alloy long shaft variable diameter parts comprises the following steps:

[0005] (1) Heat the blank to below T β 20~60℃, and keep warm;

[0006] (2) After the insulation is completed, radial forging is used to forge the bar blank;

[0007] Among them, in step (2), by controlling the size of each pressing amount, the setting of the deformation amount in the whole forging process follows the principle of first small, then large and finally small again, and the one-way feeding forging technology is adopted.

[0008] The present invention effectively manages the generation of heat during the forging process by precisely controlling the amount of pressure applied each time and following a carefully designed distribution criterion for small and large passes. The one-way feed forging technology is used to provide sufficient cooling time for the blank, thereby effectively controlling the temperature rise during the forging process. Combining these technical means, the present invention can effectively control the forging temperature during the forming process of long-axis variable-diameter parts and achieve near-isothermal forging, thereby significantly improving the product's organizational uniformity and performance stability, and can overcome the problems of overheating and uneven temperature distribution caused by the poor thermal conductivity of titanium alloys, thereby ensuring the product's forming quality and performance under high-temperature forging conditions.

[0009] Also provided are products manufactured according to the near-isothermal radial forging method for titanium alloy long shaft-type reduced-diameter parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a drawing of the titanium alloy part obtained in Example 1 of the present invention.

[0011] Figure 2 This is the microstructure of the end of the titanium alloy part obtained in Example 1 of the present invention.

[0012] Figure 3 This is the microstructure of the tail of the titanium alloy part obtained in Example 1 of the present invention.

[0013] Figure 4 This is a drawing of a titanium alloy part obtained in Example 2 of the present invention.

[0014] Figure 5 This is the microstructure of the end of the titanium alloy part obtained in Example 2 of the present invention.

[0015] Figure 6 This is the microstructure of the tail of the titanium alloy part obtained in Example 2 of the present invention.

[0016] Figure 7 The present invention is a flow chart of a near-isothermal radial forging method for titanium alloy long shaft-type variable-diameter parts. DETAILED DESCRIPTION

[0017] like Figure 7 As shown, the near-isothermal radial forging method for titanium alloy long shaft variable diameter parts comprises the following steps:

[0018] (1) Heat the blank to below T β 20~60℃, and keep warm;

[0019] (2) After the insulation is completed, radial forging is used to forge the bar blank;

[0020] Among them, in step (2), by controlling the size of each pressing amount, the setting of the deformation amount in the whole forging process follows the principle of first small, then large and finally small again, and the one-way feeding forging technology is adopted.

[0021] The present invention effectively manages the generation of heat during the forging process by precisely controlling the amount of pressure applied each time and following a carefully designed distribution criterion for small and large passes. The one-way feed forging technology is used to provide sufficient cooling time for the blank, thereby effectively controlling the temperature rise during the forging process. Combining these technical means, the present invention can effectively control the forging temperature during the forming process of long-axis variable-diameter parts and achieve near-isothermal forging, thereby significantly improving the product's organizational uniformity and performance stability, and can overcome the problems of overheating and uneven temperature distribution caused by the poor thermal conductivity of titanium alloys, thereby ensuring the product's forming quality and performance under high-temperature forging conditions.

[0022] Preferably, in the step (1), the heating method is to heat the resistance furnace to a specified temperature and then load the blank into the furnace, and start timing after the furnace is heated to the forging temperature, and the insulation coefficient is 0.5 to 0.6.

[0023] Preferably, in step (2), the blank is forged in multiple passes using a radial forging machine according to the size of the finished part, and the final forging size is based on a processing allowance of 5 to 10 mm relative to the size of the finished part.

[0024] Preferably, in the step (2), during the radial forging process, the forging frequency is 200 to 600 times / min, the billet feeding speed is 1 to 2 m / min, and the billet rotation speed is 15 to 25 r / min.

[0025] Preferably, in the step (2), the radial forging process has a pressing depth of 5 to 20 mm per pass.

[0026] Preferably, in the step (2), variable diameter forming is achieved by adjusting the hammer head during each forming process, thereby shortening the forming time and improving the temperature uniformity during the forging process.

[0027] Preferably, in step (2), each forging pass is started from the same end of the bar. After each forging pass is completed, the hammer head is lifted and the bar is moved to the initial forging position using a chuck before the next forging pass is performed, so as to allow cooling time for the blank and control the forging temperature rise.

[0028] Preferably, in the step (2), each forging process is performed by drawing to improve the straightness of the forging blank.

[0029] Also provided are products manufactured according to the near-isothermal radial forging method for titanium alloy long shaft-type reduced-diameter parts.

[0030] The specific embodiments of the present invention are described in detail below.

[0031] Embodiment 1:

[0032] Figure 1 This is the product drawing of Example 1. The product grade is TC4, and the size of the bar blank used is Φ150mm. The following steps are implemented:

[0033] (1) The resistance furnace is heated to 940℃ (T β -40℃), put the TC4 titanium alloy billet into the furnace, start timing when it reaches temperature again, and keep warm for 80 minutes.

[0034] (2) The heated bar blank obtained in step (1) is radially forged using a GFM SX-25 radial forging machine. The forging is performed in 4 passes. For the finished product with a diameter of 120 mm, the deformation size of each pass is 150 mm-145 mm-135 mm-130 mm-125 mm, and for the finished product with a diameter of 100 mm, the deformation size of each pass is 150 mm-145 mm-125 mm-110 mm-105 mm. During the forging process, the forging frequency is 415 times / min, the billet feed speed is 1.5 m / min, and the billet rotation speed is 18 r / min. In the diameter change stage, the hammer adjustment function is used to reduce the diameter by 10 mm. The forging process starts from the left side and adopts a pulling method. After each forging pass is completed, the hammer is lifted and the bar is moved to the initial position of the forging using the chuck before the next forging pass is performed.

[0035] The TC4 titanium alloy parts obtained in Example 1 have uniform microstructure and good comprehensive mechanical properties.

[0036] Table 1 shows the chemical composition of the TC4 titanium alloy bar blank used in Example 1.

[0037] Table 1

[0038]

[0039] Table 2 shows the mechanical properties of the TC4 titanium alloy parts obtained in Example 1.

[0040] Table 2

[0041]

[0042] Figure 2 The microstructure of the end of the titanium alloy part obtained in Example 1 of the present invention is shown in FIG. Figure 3 This is the microstructure of the tail of the titanium alloy part obtained in Example 1 of the present invention.

[0043] Embodiment 2:

[0044] Figure 4 This is the product drawing of Example 2. The product grade is TC18, and the size of the bar blank used is Φ170mm. The following steps are implemented:

[0045] (1) The resistance furnace is heated to 840℃2(T β -40℃), put the TC18 titanium alloy billet into the furnace, start timing when it reaches temperature again, and keep warm for 90 minutes.

[0046] (2) Radial forging was performed on the heated bar blank obtained in step (1) using a GFM RF-40 radial forging machine. For the finished product with a diameter of 150 mm, forging was performed in 3 passes, and the deformation size of each pass was 170 mm-165 mm-150 mm-145 mm; for the finished product with a diameter of 100 mm, forging was performed in 5 passes, and the deformation size of each pass was 170 mm-165 mm-145 mm-125 mm-110 mm-105 mm; during the forging process, the forging frequency was 225 times / min, the billet feed speed was 1 m / min, and the billet rotation speed was 15 r / min; during the diameter reduction stage, the hammer adjustment function was used to lower and lift 20 mm to achieve diameter reduction; the forging process was started from the left side, and the pulling method was adopted. After each forging pass was completed, the hammer was lifted, and the bar was moved to the initial position of forging using the chuck before the next forging pass was performed.

[0047] The TC18 titanium alloy parts obtained in Example 2 have uniform microstructure and good comprehensive mechanical properties.

[0048] Table 3 shows the chemical composition of the TC18 titanium alloy bar blank used in Example 2.

[0049] Table 3

[0050]

[0051] Table 4 shows the mechanical properties of the TC18 titanium alloy parts obtained in Example 2.

[0052] Table 4

[0053]

[0054] Figure 5 The microstructure of the end of the titanium alloy part obtained in Example 2 of the present invention is shown in FIG. Figure 6 This is the microstructure of the tail of the titanium alloy part obtained in Example 2 of the present invention.

[0055] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. A near-isothermal radial forging method for titanium alloy long shaft variable diameter parts, characterized in that: It includes the following steps: (1) Heat the blank to below T β 20~60℃, and keep warm; (2) After the insulation is completed, radial forging is used to forge the bar blank; Among them, in step (2), by controlling the size of each pressing amount, the setting of the deformation amount in the whole forging process follows the principle of first small, then large and finally small again, and the one-way feeding forging technology is adopted.

2. The near-isothermal radial forging method for titanium alloy long shaft variable diameter parts according to claim 1, characterized in that: In the step (1), the heating method is to heat the resistance furnace to a specified temperature and then load the blank into the furnace, and start timing after the furnace is heated to the forging temperature, and the insulation coefficient is 0.5 to 0.

6.

3. The near-isothermal radial forging method for titanium alloy long shaft variable diameter parts according to claim 1, characterized in that: In the step (2), the blank is forged in multiple passes using a radial forging machine according to the size of the finished part, and the final forging size is based on a processing allowance of 5 to 10 mm relative to the size of the finished part.

4. The near-isothermal radial forging method for titanium alloy long shaft variable diameter parts according to claim 3, characterized in that: In the step (2), during the radial forging process, the forging frequency is 200 to 600 times / min, the billet feeding speed is 1 to 2 m / min, and the billet rotating speed is 15 to 25 r / min.

5. The near-isothermal radial forging method for titanium alloy long shaft variable diameter parts according to claim 3, characterized in that: In the step (2), the radial forging process has a pressing depth of 5 to 20 mm per pass.

6. The near-isothermal radial forging method for titanium alloy long shaft variable diameter parts according to claim 3, characterized in that: In the step (2), variable diameter forming is achieved by adjusting the hammer head during each forming process.

7. The near-isothermal radial forging method for titanium alloy long shaft variable diameter parts according to claim 3, characterized in that: In the step (2), each forging pass starts from the same end of the bar. After each forging pass is completed, the hammer head is lifted and the bar is moved to the initial forging position using a chuck before the next forging pass is performed, leaving cooling time for the blank and controlling the forging temperature rise.

8. The near-isothermal radial forging method for titanium alloy long shaft variable diameter parts according to claim 3, characterized in that: In the step (2), each forging process is performed by drawing and beating.

9. A product manufactured by the near-isothermal radial forging method for titanium alloy long shaft variable diameter parts according to any one of claims 1 to 8.

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