Adjustable high-strength titanium alloy pipe ion nitriding auxiliary tooling

Abstract

The utility model discloses an adjustable high -strength titanium alloy pipe ion nitriding auxiliary frock relates to TC4 titanium alloy surface heat treatment technical field, including the TC4 pipe of nitriding, auxiliary cathode, N type temperature measurement thermocouple and temperature recorder, and auxiliary cathode is the round bar material of adoption TC4 titanium alloy, and the diameter of round bar material is 10 12mm less than the TC4 pipe of nitriding, and the small hole of depth 200mm, diameter 5mm is processed to the center of round bar material, and N type temperature measurement thermocouple is installed in the small hole, realizes the high accuracy temperature measurement and control of ±1 DEG C, ensures the temperature of remaining parts in the furnace to maintain in the safety range, avoids the damage to equipment due to high temperature, guarantees nitrogenization process stable controllable simultaneously, and nitrogenization time is shortened, and the efficiency is improved. And the surface is golden after nitriding, and the effect is even, effectively solve the problem of low surface hardness, poor wear resistance and uneven nitriding, and the comprehensive performance and product quality of TC4 titanium alloy pipe are greatly improved.

Description

Technical Field

[0001] This utility model relates to the field of TC4 titanium alloy surface heat treatment technology, and in particular to an adjustable high-strength titanium alloy tube ion nitriding auxiliary tooling. Background Technology

[0002] TC4 titanium alloy (Ti-6Al-4V) is an α+β type titanium alloy, mainly composed of titanium (balance), aluminum (5.5-6.8%), and vanadium (3.5-4.5%), with trace amounts of oxygen and iron. Its significant characteristics include: low density—4.43-4.51 g / cm³, only 60% of that of steel, offering significant lightweight advantages; high specific strength—tensile strength reaches 895-1200 MPa, yield strength 825-1100 MPa, with a specific strength (strength / density) far exceeding that of steel; and excellent corrosion resistance—a dense oxide film forms on the surface, resisting seawater, acid, and alkali corrosion, making it suitable for marine and chemical environments. Due to its lightweight, high strength, and corrosion resistance, TC4 titanium alloy has become a core material in aerospace, medical, and other fields. Although its mechanical properties can be flexibly controlled through heat treatment processes such as annealing, solution treatment, and aging to meet different working conditions, its surface hardness after heat treatment is only 35-40 HRC, indicating low surface hardness and poor wear resistance.

[0003] Plasma nitriding is an advanced process that uses glow discharge to strengthen metal surfaces in a vacuum environment. Its core principle is to bombard the workpiece surface with high-energy ions, forming active nitrogen atoms that penetrate the material surface to create a high-hardness, wear-resistant nitride layer.

[0004] After ion nitriding, the surface hardness of TC4 titanium alloy can reach over 1200 HV, significantly improving its wear resistance. However, the rated temperature of conventional industrial ion nitriding furnaces is only 650℃, which cannot reach the nitriding temperature of 800-900℃ for titanium alloys. At 650℃, the nitriding rate of titanium alloys is relatively slow, and the hardness improvement is not significant.

[0005] To address the aforementioned technical issues, an adjustable high-strength titanium alloy tube ion nitriding auxiliary tooling is proposed. Utility Model Content

[0006] To address the shortcomings of existing technologies, this utility model provides an adjustable auxiliary tooling for ion nitriding of high-strength titanium alloy tubes. It addresses the problem that the rated temperature (650℃) of conventional ion nitriding furnaces cannot meet the high temperature (800-900℃) required for nitriding TC4 titanium alloy tubes, resulting in slow nitriding speed, insufficient hardness improvement, and uneven nitriding. By designing auxiliary cathodes and other devices, the discharge effect is enhanced to increase the tube temperature, achieving precise temperature control and thus improving nitriding quality and efficiency.

[0007] To achieve the above objectives, this utility model provides the following technical solution:

[0008] An adjustable high-strength titanium alloy tube ion nitriding auxiliary tooling includes a nitrided TC4 tube, an auxiliary cathode, an N-type thermocouple, and a temperature recording instrument.

[0009] The auxiliary cathode is a round bar made of TC4 titanium alloy. The diameter of the round bar is 10-12 mm smaller than that of the nitrided TC4 tube. A small hole with a depth of 200 mm and a diameter of 5 mm is machined in the center of the round bar. The N-type temperature measuring thermocouple is installed in the small hole.

[0010] The temperature recording instrument is electrically connected to an N-type thermocouple for measuring and recording the nitriding temperature.

[0011] Preferably, the length of the auxiliary cathode is the same as the length of the nitrided TC4 tube.

[0012] Preferably, the surface of the auxiliary cathode is polished, and the surface roughness Ra ≤ 0.8 μm.

[0013] Preferably, the temperature recording instrument has a data storage function and can store at least 100 sets of nitriding temperature data.

[0014] Preferably, it also includes a fixing bracket for fixing the auxiliary cathode inside the ion nitriding furnace, and the auxiliary cathode is coaxially arranged with the TC4 tube being nitrided.

[0015] Preferably, the fixed bracket includes an insulating support and a metal connector. The insulating support is used to isolate the auxiliary cathode from the inner wall of the ion nitriding furnace, and the metal connector is used to fix the position of the auxiliary cathode.

[0016] Preferably, the temperature recording instrument is equipped with an alarm module, which will sound an alarm when the measured temperature exceeds the set nitriding temperature range of 800-900℃.

[0017] Preferably, the measuring end of the N-type temperature measuring thermocouple is located at the bottom of the orifice, and the space between the N-type temperature measuring thermocouple and the inner wall of the orifice is filled with high-temperature resistant insulating thermally conductive adhesive.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] I. Precise Temperature Control Overcoming Equipment Limitations: By utilizing the discharge effect of the auxiliary cathode, the temperature of the TC4 titanium alloy tube is precisely increased to the ideal nitriding range of 800-900℃, under the condition that the rated temperature of the ion nitriding furnace is only 650℃, thus overcoming the equipment's temperature bottleneck. Combined with N-type thermocouples and temperature recording instruments, high-precision temperature measurement and control within ±1℃ is achieved, ensuring that the temperature of other parts of the furnace remains within a safe range, preventing damage to the equipment due to high temperatures, and ensuring a stable and controllable nitriding process.

[0020] II. Significantly Improved Nitriding Quality and Efficiency: Compared to traditional nitriding methods, this auxiliary device can increase the surface hardness of TC4 titanium alloy tubes from 900-1000 HV to 1300-1400 HV; nitriding time is shortened, and efficiency is improved. Furthermore, the nitrided surface is golden yellow and uniform, effectively solving the problems of low surface hardness, poor wear resistance, and uneven nitriding, significantly improving the overall performance and product quality of TC4 titanium alloy tubes. Attached Figure Description

[0021] The above description is only an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, the preferred embodiments of this utility model are described in detail below with reference to the accompanying drawings.

[0022] Figure 1 This is a schematic diagram of the structure of this utility model.

[0023] Legend: 1. Nitrided TC4 tube; 2. Auxiliary cathode; 3. N-type thermocouple; 4. Temperature recording instrument. Detailed Implementation

[0024] This application provides an adjustable auxiliary tooling for ion nitriding of high-strength titanium alloy tubes. It addresses the problem that the rated temperature (650℃) of conventional ion nitriding furnaces cannot meet the high temperature (800-900℃) required for nitriding of TC4 titanium alloy tubes, resulting in slow nitriding speed, insufficient hardness improvement, and uneven nitriding. By designing auxiliary cathodes and other devices, the discharge effect is enhanced to increase the temperature of the tube, achieving precise temperature control and thus improving the nitriding quality and efficiency.

[0025] Example

[0026] like Figure 1 As shown, the overall technical solution in this application embodiment is as follows:

[0027] To address the problems existing in the prior art, this utility model provides an adjustable high-strength titanium alloy tube ion nitriding auxiliary tooling, including a nitrided TC4 tube 1, an auxiliary cathode 2, an N-type thermocouple 3, and a temperature recording instrument 4.

[0028] The auxiliary cathode 2 is a round bar made of TC4 titanium alloy. The diameter of the round bar is 10-12 mm smaller than that of the nitrided TC4 tube 1. A small hole with a depth of 200 mm and a diameter of 5 mm is machined in the center of the round bar. The N-type temperature measuring thermocouple 3 is installed in the small hole.

[0029] Temperature recording instrument 4 is electrically connected to N-type thermocouple 3 for measuring and recording nitriding temperature;

[0030] The length of the auxiliary cathode 2 is the same as the length of the nitrided TC4 tube 1. The surface of the auxiliary cathode 2 is polished and the surface roughness Ra≤0.8μm. The temperature recording instrument 4 has a data storage function and can store at least 100 sets of nitriding temperature data.

[0031] The device also includes a fixing bracket for fixing the auxiliary cathode 2 inside the ion nitriding furnace. The auxiliary cathode 2 is coaxially arranged with the nitrided TC4 tube 1. The fixing bracket includes an insulating support and a metal connector. The insulating support is used to isolate the auxiliary cathode 2 from the inner wall of the ion nitriding furnace, and the metal connector is used to fix the position of the auxiliary cathode 2. The temperature recording instrument 4 is equipped with an alarm module. When the measured temperature exceeds the set nitriding temperature range of 800-900℃, the alarm module will sound an alarm. The temperature measuring end of the N-type temperature measuring thermocouple 3 is located at the bottom of the orifice, and the space between the N-type temperature measuring thermocouple 3 and the inner wall of the orifice is filled with high-temperature resistant insulating thermally conductive adhesive.

[0032] The core principle of this auxiliary device is to enhance the ion nitriding effect of the TC4 titanium alloy tube by utilizing the discharge effect of the auxiliary cathode 2. At the same time, through the cooperation of the N-type thermocouple 3 and the temperature recording instrument 4, the nitriding temperature is precisely controlled. Under the premise of not exceeding the rated temperature of the ion nitriding furnace, the TC4 titanium alloy tube reaches the ideal nitriding temperature range of 800-900℃, thereby improving the nitriding quality.

[0033] The auxiliary cathode 2 is made of TC4 titanium alloy, and its manufacturing process is as follows:

[0034] Material Selection and Machining: TC4 titanium alloy bars conforming to GB / T3621-2016 standard are selected. Based on the inner diameter of the nitrided TC4 tube 1, the diameter of the auxiliary cathode 2 round bar is machined to be 10-12 mm smaller than that of the nitrided TC4 tube 1. For example, if the inner diameter of the nitrided TC4 tube 1 is 50 mm, the diameter of the auxiliary cathode 2 round bar is machined to 38-40 mm. Subsequently, a high-precision lathe is used to machine a small hole with a depth of 200 mm and a diameter of 5 mm in the center of the round bar, with machining accuracy controlled within ±0.1 mm to ensure accurate installation of the N-type temperature measuring thermocouple 3.

[0035] Surface treatment: The surface of auxiliary cathode 2 is polished using a combination of mechanical and electrolytic polishing. First, mechanical polishing reduces the surface roughness to Ra ≤ 1.6 μm, followed by electrolytic polishing to achieve a final surface roughness of Ra ≤ 0.8 μm. A smooth surface enhances the discharge effect and promotes a uniform ion nitriding process.

[0036] Installation and Fixing: The auxiliary cathode 2 is installed inside the ion nitriding furnace using a fixing bracket. The fixing bracket consists of an insulating support and metal connectors. The insulating support is made of high-purity alumina ceramic material with an insulation resistance greater than 10¹²Ω, effectively isolating the auxiliary cathode 2 from the inner wall of the ion nitriding furnace and preventing short circuits. The metal connectors are made of 304 stainless steel and are fixed to the auxiliary cathode 2 using bolts, ensuring that the auxiliary cathode 2 and the nitrided TC4 tube 1 are coaxially aligned, with a coaxiality error controlled within ±0.5mm.

[0037] Installation and commissioning of N-type temperature measuring thermocouple 3 and temperature recording instrument 4:

[0038] Installation of Type N thermocouple 3: Insert the Type N thermocouple 3 into the small hole of the auxiliary cathode 2, ensuring that the measuring end is at the bottom of the small hole. To ensure the accuracy and stability of temperature measurement, fill the space between the Type N thermocouple 3 and the inner wall of the small hole with high-temperature resistant insulating thermally conductive adhesive. This adhesive has a thermal conductivity of not less than 1.5 W / (m·K) at a high temperature of 800-900℃ and an insulation resistance greater than 10¹. 0 Ω. The N-type temperature measuring thermocouple 3 is electrically connected to the temperature recording instrument 4 using high-temperature resistant wires. The outer layer of the wires is wrapped with a high-temperature resistant insulating sleeve to prevent damage to the wires under high-temperature conditions.

[0039] Temperature Recorder 4 Debugging: The temperature recorder 4 should be a model with high-precision measurement accuracy of ±1℃ and data storage function, capable of storing at least 100 sets of nitriding temperature data. Before installation, the temperature recorder 4 should be calibrated using a standard temperature source at multiple points within the range of 0-1000℃ to ensure accurate and reliable measurement data. Simultaneously, set the temperature threshold for the alarm module. When the measured temperature exceeds the set nitriding temperature range of 800-900℃, the alarm module will immediately issue an audible and visual alarm to remind the operator to make timely adjustments.

[0040] Usage process:

[0041] Pretreatment: The TC4 tube 1 to be nitrided is pretreated by degreasing, pickling and other processes to remove surface oil and oxide film. Then it is installed together with the auxiliary cathode 2 in the ion nitriding furnace to ensure that the two are coaxial and have a uniform spacing.

[0042] Heating and Nitriding: Close the furnace door of the ion nitriding furnace, evacuate the furnace until the internal pressure is below 1 Pa, then introduce ammonia gas to maintain the furnace pressure at 200-500 Pa. Start the power supply, adjust the nitriding current, and the auxiliary cathode 2 begins to discharge. Its discharge effect enhances the ion bombardment of the TC4 titanium alloy tube surface, causing the temperature of the nitrided TC4 tube 1 to gradually rise. The N-type thermocouple 3 measures the temperature of the nitrided TC4 tube 1 in real time and transmits the data to the temperature recording instrument 4 for display and storage. Based on the data displayed on the temperature recording instrument 4, the operator adjusts the nitriding current to accurately control the temperature of the nitrided TC4 tube 1 between 800-900℃, while the temperature of the rest of the furnace remains below the rated temperature of the ion nitriding furnace (650℃).

[0043] Heat preservation and cooling: After holding at 800-900℃ for a certain period of time, usually 4-8 hours depending on the specific process requirements, stop the supply of ammonia gas, gradually reduce the nitriding current, and allow the nitrided TC4 tube 1 to cool to room temperature with the furnace before being taken out of the furnace.

[0044] This invention effectively solves the problems of insufficient temperature and poor nitriding effect during the ion nitriding process of TC4 titanium alloy tubes through innovative design and optimized combination of auxiliary cathode 2, N-type temperature measuring thermocouple 3, temperature recording instrument 4 and fixed bracket. It has high practical value and promotion significance.

[0045] Finally, it should be noted that the above embodiments are merely examples for clearly illustrating the present invention and are not intended to limit the implementation. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. An adjustable high-strength titanium alloy tube ion nitriding auxiliary tooling, characterized in that, It includes a nitrided TC4 tube (1), an auxiliary cathode (2), an N-type thermocouple (3), and a temperature recording instrument (4). The auxiliary cathode (2) is a round bar made of TC4 titanium alloy. The diameter of the round bar is 10-12 mm smaller than that of the nitrided TC4 tube (1). A small hole with a depth of 200 mm and a diameter of 5 mm is machined in the center of the round bar. The N-type temperature measuring thermocouple (3) is installed in the small hole. The temperature recording instrument (4) is electrically connected to the N-type thermocouple (3) for measuring and recording the nitriding temperature.

2. The adjustable high-strength titanium alloy tube ion nitriding auxiliary tooling as described in claim 1, characterized in that: The length of the auxiliary cathode (2) is the same as the length of the nitrided TC4 tube (1).

3. The adjustable high-strength titanium alloy tube ion nitriding auxiliary tooling as described in claim 1, characterized in that: The surface of the auxiliary cathode (2) is polished to a surface roughness Ra≤0.8μm.

4. The adjustable high-strength titanium alloy tube ion nitriding auxiliary tooling as described in claim 1, characterized in that: The temperature recording instrument (4) has a data storage function and can store at least 100 sets of nitriding temperature data.

5. The adjustable high-strength titanium alloy tube ion nitriding auxiliary tooling as described in claim 1, characterized in that: It also includes a fixing bracket for fixing the auxiliary cathode (2) inside the ion nitriding furnace, and the auxiliary cathode (2) is coaxially arranged with the nitrided TC4 tube (1).

6. The adjustable high-strength titanium alloy tube ion nitriding auxiliary tooling as described in claim 5, characterized in that: The fixed bracket includes an insulating support and a metal connector. The insulating support is used to isolate the auxiliary cathode (2) from the inner wall of the ion nitriding furnace, and the metal connector is used to fix the position of the auxiliary cathode (2).

7. The adjustable high-strength titanium alloy tube ion nitriding auxiliary tooling as described in claim 1, characterized in that: The temperature recording instrument (4) is equipped with an alarm module. When the measured temperature exceeds the set nitriding temperature range of 800-900℃, the alarm module will issue an alarm.

8. The adjustable high-strength titanium alloy tube ion nitriding auxiliary tooling as described in claim 1, characterized in that: The temperature measuring end of the N-type temperature measuring thermocouple (3) is located at the bottom of the orifice, and the N-type temperature measuring thermocouple (3) and the inner wall of the orifice are filled with high-temperature resistant insulating thermally conductive adhesive.

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