Titanium alloy TA15 ball head processing and vacuum heat treatment method

Abstract

The application discloses a titanium alloy TA15 ball head processing and vacuum heat treatment method, which comprises the following steps: end face and spherical surface machining and drilling processing are performed on a titanium alloy material to obtain a ball blank; the spherical surface of the ball blank is ground; ultrasonic cleaning is performed; alpha heat treatment is performed; two end faces are machined, a hole is bored, and deburring and grinding polishing treatment are performed; after the ultrasonic cleaning, milling is performed, and then the ultrasonic cleaning is performed again, so that the preparation of the titanium alloy ball head is completed. After the processing by the alpha heat treatment process, the titanium alloy ball blank is heat treated under a certain vacuum state and a specific temperature, a hard titanium oxide is formed on the surface of the titanium alloy ball blank, the surface hardness of the titanium alloy ball blank is strengthened, and the surface hardness and wear resistance of the titanium alloy ball blank after the strengthening are improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aerospace processing, and particularly relates to a titanium alloy TA15 ball head processing and vacuum heat treatment method. BACKGROUND

[0002] Titanium alloy material has the performance of high strength and low specific gravity, excellent corrosion resistance, and is widely used in the field of aerospace as a structural and functional material. Titanium alloy material heat treatment is an important link in the quality control of aerospace products. Due to the high temperature performance (500℃) of titanium alloy, it is easy to combine with harmful gases such as oxygen, nitrogen and hydrogen in the air, and form hard and brittle compounds such as oxides and nitrides on the surface, which affects the performance of the product. In order to avoid or reduce its harm, the processing cutting allowance of the base metal is increased, or the harmful gases in the air are reduced by titanium alloy heat treatment, that is, vacuum heat treatment method, which is used to heat treat titanium alloy parts in a vacuum state in a heating furnace, so as to reduce the thickness of the surface compound as much as possible, and achieve the purpose of reducing the processing cutting allowance.

[0003] However, titanium alloy has the disadvantages of low hardness, easy adhesion and poor wear resistance. The hardness of titanium alloy TA15 in the annealed state is not more than HV370; for specific titanium alloy products, the surface needs to have high hardness and wear resistance.

[0004] The patent document with the publication number CN118033078A discloses a method for predicting the thickness of the oxygen-rich alpha layer during the heat treatment of two-phase titanium alloy sheet. The patent discloses that the higher the temperature, the smaller the oxygen concentration, and titanium alloy will not be oxidized at high temperature in a vacuum state. However, after multiple tests, it was found that the surface of the titanium alloy part can also be oxidized when the temperature is close to or exceeds the phase transition temperature in a low vacuum state.

[0005] The patent document with the publication number CN113714286A discloses a preparation method of TA15 titanium alloy thin strip. The patent discloses the step of vacuum heat treatment, but the patent is directed to the preparation of TA15 titanium alloy thin strip, and prevents the generation of cracks in the edge of TA15 titanium alloy thin strip caused by excessive deformation in the pass. The technical problem solved by the patent is different from the present application.

[0006] The patent document with the publication number CN111348634A discloses a preparation method of layered alpha-titanium phosphate, but the technical field involved is different from the present application. SUMMARY

[0007] To solve the above technical problems, the present application provides a titanium alloy TA15 ball head processing and vacuum heat treatment method.

[0008] The present application is realized by the following technical solutions.

[0009] A processing method of a titanium alloy TA15 ball head, comprising the following steps:

[0010] S1: end face and spherical surface turning and inner hole drilling of the titanium alloy material are performed to obtain a ball blank;

[0011] S2: the spherical surface of the ball blank is ground;

[0012] S3: ultrasonic cleaning is performed;

[0013] S4: vacuum heat treatment is performed, and alpha heat treatment is performed to obtain a ball blank containing an alpha layer;

[0014] S5: two end faces are turned, an inner hole is bored, and deburring and grinding and polishing treatment are performed;

[0015] S6: ultrasonic cleaning is performed, then milling is performed, then ultrasonic cleaning is performed again, and finally the preparation of the titanium alloy ball head is completed;

[0016] In the step S1, the titanium alloy material is annealed TA15 bar stock, the outer circle of the bar stock is used as a positioning reference during processing, the outer circle of the bar stock is clamped, the bar stock excess and black oxide skin are removed, end face and spherical surface turning, inner hole drilling and other dimensions are performed to meet the requirements of the drawing, and the spherical surface roughness of the ball blank reaches Ra0.8;

[0017] In the step S2, the ball inner hole of the ball blank is used as a positioning reference, then the ball blank is fixed by a clamp and mounted on a grinding and polishing device, the radial runout of the clamp is not greater than 0.03, the grinding and polishing device drives the ball to rotate at 2000-2800 r / min, the ball blank is ground and polished until the spherical surface roughness of the ball blank reaches Ra0.4;

[0018] The ultrasonic cleaning steps in the steps S3 and S6 include: the ball blank is soaked in a cleaning liquid for 20-30 minutes, then cleaned at 40-60°C for 20-30 minutes, the part is taken out to check whether the surface dirt is removed, and then blown dry;

[0019] The alpha heat treatment step in the step S4 includes: the ball blank is loaded into a basket, the spacing between adjacent ball blanks is greater than 10 mm, then loaded into a vacuum furnace, the vacuum degree in the vacuum furnace is extracted to below 10 Pa, the temperature is started to rise, the preheating temperature is 870±10°C, the temperature is kept for 1 h, the vacuum degree is controlled at 400-500 Pa, the temperature is continuously increased to the alpha heat treatment temperature 970±10°C, the temperature is kept for 2 h, the vacuum degree is controlled at 1200-1500 Pa during this period, 10 Pa argon gas is filled for cooling, and oxygen is uniformly penetrated. 5 Pa argon gas is filled for cooling, and oxygen is uniformly penetrated.

[0020] Preferably, in the step S5, the machining allowance of the two end face turning and inner hole boring is 0.25 mm or more, and deburring and grinding and polishing treatment is performed, and the roughness of the surface oxide layer of the obtained ball blank reaches Ra0.4.

[0021] Preferably, in the step S6, after the ultrasonic cleaning, milling is performed to obtain a circular arc oil groove on the ball blank, then deburring and cleaning of the part are performed, and finally the preparation of the titanium alloy ball head is completed.

[0022] Preferably, the clamp comprises a positioning shaft, a pressing plate and a screw, one side of the positioning shaft is provided with a connecting part A, the other side of the positioning shaft is provided with a connecting part B, the connecting part A is positioned through the ball inner hole of the ball blank, the connecting part B is connected with the grinding and polishing device, the screw is threadedly connected with the connecting part A, and the pressing plate is arranged between the connecting part A and the screw.

[0023] Preferably, the grinding and polishing device comprises a speed regulating motor, a sleeve coupling and a drill bit clamp, the speed regulating motor is connected through the sleeve coupling and the drill bit clamp, and the drill bit clamp is connected with the clamp.

[0024] A titanium alloy ball head prepared by the above method comprises a ball head body and a ball inner hole arranged on the ball head body.

[0025] The beneficial effects of the present application are as follows:

[0026] After being processed by the alpha heat treatment process of the present application, the titanium alloy ball blank is heat treated under a certain vacuum state and a specific temperature, a hard titanium oxide is formed on the surface of the titanium alloy ball blank, the surface hardness is strengthened, and the surface hardness and wear resistance after strengthening are improved. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is the processing flowchart of the present application;

[0028] Figure 2 is a structural schematic diagram of the clamp of the present application;

[0029] Figure 3 is a structural schematic diagram of the grinding and polishing device of the present application;

[0030] Figure 4 is a structural schematic diagram of the positioning shaft of the present application;

[0031] Figure 5 is a structural schematic diagram of the ball blank of the present application;

[0032] In the figure: 1-ball inner hole, 2-positioning shaft, 21-connecting part A, 22-connecting part B, 3-pressing plate, 4-screw, 5-speed regulating motor, 6-sleeve coupling, 7-drill bit clamp. DETAILED DESCRIPTION

[0033] The technical solutions of the present application are further described below, but the scope of protection is not limited to the description.

[0034] Example 1:

[0035] As Figures 1-5 shown, a processing method of titanium alloy TA15 ball head, comprising the following steps:

[0036] S1: end face and spherical surface of titanium alloy material are turned, inner hole is drilled, and a ball blank is obtained;

[0037] S2: the spherical surface of the ball blank is ground;

[0038] S3: ultrasonic cleaning;

[0039] S4: vacuum heat treatment, α heat treatment is carried out, and a ball blank containing an α layer is obtained;

[0040] S5: two end faces and an inner hole are bored, and deburring and grinding and polishing treatment are carried out;

[0041] S6: ultrasonic cleaning is carried out, then milling is carried out, then ultrasonic cleaning is carried out again, finally the preparation of the titanium alloy ball head is completed, finally final inspection is carried out according to the drawing size, and then packaging and storage are carried out; wherein, contact with aluminum-magnesium alloy is strictly prohibited during production and inspection, and contact with liquid and gas containing chloride ions is prohibited during cleaning, turnover and storage.

[0042] In the step S1, the titanium alloy material is annealed TA15 rod stock, the outer circle of the rod stock is used as a positioning reference during processing, the outer circle of the rod stock is clamped, the rod stock excess and black oxide skin are removed, end faces and spherical surfaces are turned, an inner hole is drilled, and other sizes meet the requirements of the drawing, and the spherical surface roughness of the ball blank reaches Ra0.8.

[0043] In the step S2, the ball inner hole 1 of the ball blank is positioned, then the ball blank is fixed and mounted on a grinding and polishing device through a clamp, the radial runout of the clamp is not greater than 0.03, the grinding and polishing device drives the ball to rotate at 2000-2800 r / min, the ball blank is ground and polished by using gold ZP-UN diamond grinding paste with a particle size of W2.5 and white cleaning cloth; until the spherical surface roughness of the ball blank reaches Ra0.4, the surface is smooth and uniform, which is beneficial to the formation of a uniform oxidation layer during α heat treatment.

[0044] When the ball blank is sleeved on the connecting part A21, the single-sided gap between the ball inner hole 1 and the connecting part A21 is not greater than 0.02 mm, and then the ball blank is fixed on the positioning shaft 2 by using the screw 4 and the pressing plate 3. The ball blank, the positioning shaft 1 and the main shaft of the stepless speed regulation motor 5 rotate at high speed, but the ball blank does not axially move.

[0045] The ultrasonic cleaning steps of the steps S3 and S6 include: the ball blank is placed in a mesh basket and soaked in a cleaning liquid for 20 minutes, then cleaned at a water temperature of 40℃ for 20 minutes, and then the surface dirt of the part is checked, if necessary, the cleaning can be repeated, and then the part is dried by compressed air to remove the surface dirt of the part.

[0046] The α heat treatment step of the step S4 includes: loading the ball blank, keeping the interval between adjacent ball blanks greater than 10 mm, and then loading into a vacuum furnace; vacuumizing the vacuum furnace to below 10 Pa, starting to heat, to a preheating temperature of 860℃, keeping for 1 h, the vacuum degree is controlled at 400 Pa, the core and surface temperature of the part is close to and uniform with the furnace temperature; continuing to heat to an α heat treatment temperature of 960℃, keeping for 2 h, during which the vacuum degree is controlled at 1200 Pa, 10 5 Pa argon gas is filled for cooling, uniform oxygen permeation; automatic control is realized through existing sensing technology and computer control technology, the vacuum degree error is ±20 Pa, ensuring the constancy of the vacuum degree in the furnace.

[0047] The machining allowance (base metal depth) of the two end faces and the bored hole in the step S5 is 0.25 mm or more, reducing the influence of the hard and brittle compound on other mechanical properties of the part; deburring and polishing treatment are carried out, and the roughness of the hard oxide layer on the surface of the obtained ball blank reaches Ra0.4.

[0048] In the step S6, after ultrasonic cleaning, milling is carried out to obtain a circular arc oil groove on the ball blank, and then deburring and cleaning of the part are carried out to complete the preparation of the titanium alloy ball head.

[0049] The clamp includes a positioning shaft 2, a pressing plate 3 and a screw 4, one side of the positioning shaft 2 is provided with a connecting part A21, the other side of the positioning shaft 2 is provided with a connecting part B22, the connecting part A21 penetrates the ball inner hole 1 of the ball blank for positioning, the connecting part B22 is connected with the polishing device, the screw 4 is threadedly connected with the connecting part A21, and the pressing plate 3 is arranged between the connecting part B22 and the screw 4.

[0050] The polishing device includes a speed regulating motor 5, a sleeve coupling 6 and a drill bit clamp 7, the speed regulating motor 5 is connected through the sleeve coupling 6 and the drill bit clamp 7, and the drill bit clamp 7 is connected with the clamp.

[0051] Example 2:

[0052] As Figures 1-5 shown in the figure, the processing method of the titanium alloy TA15 ball head is basically the same as that of example 1, and the difference is that the polishing device drives the ball to rotate at 2800 r / min in the step S2. The ultrasonic cleaning step of the step S3 and the step S6 includes: loading the ball blank with a net basket, immersing in the cleaning liquid for 30 minutes, and then cleaning at a water temperature of 60℃ for 30 minutes.

[0053] In step S4, the α-alchemy heat treatment involves evacuating the vacuum furnace to below 10 Pa, starting the heating process, reaching a preheating temperature of 880°C, holding at that temperature for 1 hour, maintaining the vacuum at 500 Pa, and then continuing the heating process to the α-alchemy heat treatment temperature of 980°C, holding at that temperature for 2 hours, maintaining the vacuum at 1500 Pa during this period, and filling the furnace with 10... 5 Argon gas cooling and uniform oxygen permeation.

[0054] Example 3:

[0055] like Figures 1-5 As shown, the processing method of a titanium alloy TA15 ball head is basically the same as that in Example 1, except that the grinding and polishing device in step S2 drives the ball to rotate at 2400 r / min. The ultrasonic cleaning steps in steps S3 and S6 include: placing the ball blank in a mesh basket, immersing it in the cleaning solution for 26 minutes, and then cleaning it at a water temperature of 53℃ for 26 minutes.

[0056] In step S4, the α-alchemy heat treatment involves evacuating the vacuum furnace to below 10 Pa, starting the heating process, reaching a preheating temperature of 882°C, holding at that temperature for 1 hour, maintaining the vacuum at 463 Pa, and then continuing the heating process to the α-alchemy heat treatment temperature of 974°C, holding at that temperature for 2 hours, maintaining the vacuum at 1300 Pa during this period, and filling the furnace with 10... 5 Argon gas cooling and uniform oxygen permeation.

[0057] The cleaning solution used in Examples 1-3 was a phosphorus-free degreaser, and the ultrasonic cleaning frequency was 28 kHz.

[0058] The ball heads prepared in Examples 1-3 were measured using a micro Vickers hardness tester. The specific measured values ​​are shown in the table below.

[0059]

[0060] As can be seen from the table above, the measured HV0.05 values ​​of the ball heads prepared in Examples 1-3 are all greater than 500; the depth of the α-aluminate layer was determined by metallographic examination, and the measured values ​​are all greater than 0.06 mm. The measured values ​​of the hardness and depth of the α-aluminate layer meet the relevant requirements for high surface hardness and high wear resistance.

Claims

1. A method for machining a TA15 titanium alloy ball head, characterized in that, Includes the following steps: S1: The titanium alloy material is machined by turning the end face and spherical surface, and drilling the inner hole to obtain a spherical blank; S2: The spherical surface of the grinding ball blank; S3: Ultrasonic cleaning; S4: Vacuum heat treatment, followed by α-alteration heat treatment, to obtain a spherical blank containing an α layer; S5: Machine both end faces and bore the inner hole, and perform deburring and grinding / polishing treatment; S6: Perform ultrasonic cleaning, then milling, then perform ultrasonic cleaning again to finally complete the preparation of the titanium alloy ball head; In step S1, the titanium alloy material is annealed TA15 bar stock. During processing, the outer circle of the bar stock is used as the positioning reference. The outer circle of the bar stock is clamped, and the excess material and black oxide scale of the bar stock are removed first. The end face, spherical surface, inner hole and other dimensions are machined to meet the requirements of the drawing. The surface roughness of the spherical blank reaches Ra0.

8. In step S2, the ball blank is positioned by the inner hole (1) of the ball blank, and then the ball blank is fixed by the clamp and mounted on the grinding and polishing device. The radial runout of the clamp is aligned to be no more than 0.

03. The grinding and polishing device drives the ball to rotate at 2000-2800r / min to grind and polish the ball blank. The surface roughness of the spherical blank reaches Ra0.4; The ultrasonic cleaning steps S3 and S6 include: immersing the blank in the cleaning solution for 20-30 minutes, then cleaning it at 40-60℃ for 20-30 minutes, removing the part to check whether the surface dirt has been removed, and then drying it. The α-alchemy heat treatment step S4 includes: placing the billets in a basket, maintaining a gap of more than 10 mm between adjacent billets, and then placing them into a vacuum furnace; evacuating the vacuum in the furnace to below 10 Pa, starting the heating process to a preheating temperature of 870±10℃, holding at that temperature for 1 hour, controlling the vacuum at 400-500 Pa, and then continuing to heat to the α-alchemy heat treatment temperature of 970±10℃, holding at that temperature for 2 hours, during which the vacuum at 1200-1500 Pa, and filling the furnace with 10... 5 Argon gas cooling and uniform oxygen permeation.

2. The processing method of a titanium alloy TA15 ball head as described in claim 1, characterized in that: In step S5, the machining allowance for turning both end faces and boring the inner hole is 0.25 mm or more, and deburring and grinding and polishing are performed to obtain a surface roughness of Ra0.4 for the oxide layer on the surface of the ball blank.

3. The processing method of a titanium alloy TA15 ball head as described in claim 1, characterized in that: In step S6, after ultrasonic cleaning, milling is performed to obtain an arc-shaped oil groove on the ball blank, followed by deburring and cleaning of the parts, finally completing the preparation of the titanium alloy ball head.

4. The processing method of a titanium alloy TA15 ball head as described in claim 1, characterized in that: The fixture includes a positioning shaft (2), a pressure plate (3) and a screw (4). A connecting part A (21) is provided on one side of the positioning shaft (2), and a connecting part B (22) is provided on the other side of the positioning shaft (2). The connecting part A (21) is positioned through the inner hole (1) of the ball blank. The connecting part B (22) is connected to the grinding and polishing device. The screw (4) is threadedly connected to the connecting part A (21). The pressure plate (3) is disposed between the connecting part A (21) and the screw (4).

5. The processing method of a titanium alloy TA15 ball head as described in claim 1, characterized in that: The grinding and polishing device includes a speed-regulating motor (5), a sleeve coupling (6), and a drill bit chuck (7). The speed-regulating motor (5) is connected to the drill bit chuck (7) through the sleeve coupling (6), and the drill bit chuck (7) is connected to the chuck.

6. A titanium alloy TA15 ball head prepared by the method according to any one of claims 1-5, characterized in that: It includes the ball head body and the ball inner hole (1) provided on the ball head body.

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