Bearing alloy material for heat exchange automatic detection robot and preparation method thereof

Abstract

The application discloses a bearing alloy material for a heat exchange automatic detection robot and a preparation method thereof, and belongs to the technical field of metallurgy. Nb, C and Si elements are introduced into the NiTiHf-based alloy, so that the problems of poor wear resistance and poor strength and toughness of the existing bearing material are improved. The NiTiHf is a shape memory alloy material with high specific modulus, the introduction of Nb improves the strength and processing performance of the material through solid solution strengthening, the introduction of C can form a carbide ceramic phase to improve the hardness and wear resistance of the material, and the introduction of Si can improve the oxidation resistance and high-temperature lubrication wear resistance of the material. The prepared alloy has extremely high wear resistance, can greatly improve the service life, and is suitable for the working requirements of complex and severe working conditions, and is applied to the heat exchange automatic detection robot bearing which needs long-period service under harsh working conditions.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical technology, specifically relating to a bearing alloy material for an automatic heat exchange inspection robot and its preparation method. Background Technology

[0002] Robots are machines that use their own power and control capabilities to perform various functions. Through precision reducers, high power at the input end is converted into low power at the output end, allowing the robot to operate according to a pre-programmed program, replacing repetitive mechanical manual operations. The replacement of human labor by robots has received widespread attention worldwide and is gradually becoming a field of intelligent robotics with great development prospects.

[0003] The automatic heat exchanger inspection robot needs to move flexibly, stably, and safely along the tube wall, accurately locating the condenser. This necessitates the development of a remotely controllable robot body for the condenser tube heat exchanger bundle, ensuring safe and efficient operation. Among these components, the harmonic reducer is the most precise type of reducer used in robots. Its components include an elliptical cam, a flexible bearing, a flexure with an external gear ring, and a rigid wheel with an internal gear ring. The inner ring of the flexible bearing is fixed to the elliptical cam, forming the input end of the harmonic reducer, while the outer ring of the flexible bearing and the flexure form the output end. When the wave generator rotates continuously, it causes a misaligned motion between the external gear ring of the flexure and the internal gear ring of the rigid wheel, thus achieving motion transmission. Due to its high precision, large transmission ratio, high transmission efficiency, small size, and light weight, the harmonic reducer is increasingly being developed in high-end manufacturing fields such as automobile manufacturing, precision CNC machine tools, and semiconductor production equipment.

[0004] From the working principle of harmonic reducers, flexible bearings are a crucial component, and their service conditions are far more demanding than those of ordinary bearings. Firstly, the high power input of a harmonic reducer necessitates that the flexible bearing withstand rotational speeds significantly higher than those of ordinary bearings. Secondly, due to the elliptical shape of the cam, the flexible bearing undergoes elastic deformation of varying degrees and shapes during wave generator rotation. This results in the flexible bearing not only bearing higher contact and impact stresses, but also experiencing constantly shifting stress directions. Consequently, flexible bearings are more prone to premature fatigue failure during operation. The long-life requirements of flexible bearings in robot harmonic reducers place even more stringent demands on the steel used in these bearings. Besides meeting requirements for high strength, high hardness, and high wear resistance, they must also possess high purity, high microstructure uniformity, and a long fatigue life.

[0005] Currently, the field of robot harmonic reducers has long been monopolized by foreign companies. Most robot manufacturers use imported materials to manufacture key components for flexible bearing harmonic reducers. Domestic research and development of robot harmonic reducers is virtually nonexistent, which severely restricts the development of China's intelligent robot industry. Summary of the Invention

[0006] To address the aforementioned problems, the present invention aims to provide a bearing alloy material for an automatic heat exchange inspection robot and its preparation method. This material can improve the problems of poor wear resistance and poor toughness of existing bearing materials. The prepared alloy material has extremely high wear resistance, which can significantly improve its service life and make it suitable for complex and harsh working conditions.

[0007] This invention is achieved through the following technical solution:

[0008] This invention discloses a bearing alloy material for an automatic heat exchange inspection robot, which, by atomic percentage, comprises 45%–55% Ni, 40%–45% Ti, 3%–10% Hf, 1%–2% Nb, 0.5%–2% Si, and 0.5%–1.60% C.

[0009] Preferably, the hardness is 680–714 Hv, and the wear rate is 10. -6 mm 3 On the order of Nm.

[0010] This invention discloses a method for preparing the bearing alloy material for the above-mentioned automatic heat exchange inspection robot, comprising the following steps:

[0011] Step 1: Melt all components in a furnace to form molten metal;

[0012] Step 2: Pour the molten metal obtained in Step 1 into a container, and after cooling, obtain an alloy block;

[0013] Step 3: The alloy block obtained in Step 2 is heated to 900°C in a high vacuum hot pressing sintering furnace at a heating rate of 20°C / min and held at that temperature. The pressure is then manually increased to 35MPa and held. After hot pressing, the pressure is manually reduced as the temperature decreases to obtain the bearing alloy material for the heat exchange automatic detection robot.

[0014] Preferably, in step 1, the melting temperature is 1600–1640°C.

[0015] Preferably, step 2 specifically involves: preheating several wear-resistant blocks and then fixing them onto the side wall of the sand mold cavity; placing a core in the center of the sand mold cavity; pouring the molten metal obtained in step 1 into the sand mold cavity; and obtaining an alloy block after natural cooling.

[0016] More preferably, the wear-resistant block is preheated to 180-220°C.

[0017] Preferably, the pouring temperature is 1530–1550°C.

[0018] Preferably, the natural cooling time is greater than 12 hours.

[0019] Preferably, in step 3, the heat preservation time is 20 minutes.

[0020] Preferably, in step 3, the pressure holding time is 15 minutes.

[0021] Compared with the prior art, the present invention has the following beneficial technical effects:

[0022] This invention discloses a bearing alloy material for an automated heat exchange inspection robot. By introducing Nb, C, and Si elements into a NiTiHf-based alloy, it improves the poor wear resistance and low strength and toughness of existing bearing materials. NiTiHf itself is a shape memory alloy material with a high specific modulus. The introduction of Nb strengthens the material through solid solution, improving its strength and machinability. The introduction of C forms a carbide ceramic phase, increasing the material's hardness and wear resistance. The introduction of Si enhances the material's oxidation resistance and high-temperature lubrication and wear resistance. The resulting alloy exhibits extremely high wear resistance, significantly extending its service life and making it suitable for complex and harsh working conditions. It is applicable to bearings in automated heat exchange inspection robots that require long-term service under demanding conditions.

[0023] The preparation method of the bearing alloy material for the automatic heat exchange inspection robot disclosed in this invention will be analyzed from the perspective of reaction mechanism. During the melting process, the elements diffuse into each other, and after casting, a composite material is formed with NiTi phase as the matrix and HfO2, TiC, NbC and other phases as reinforcement. At the same time, Si and Nb enhance the material's properties in the form of solid solution. After casting, there are some pores inside the matrix. Hot pressing can further improve the density of the material and refine the grains to a certain extent. Through solid solution strengthening and precipitation strengthening of alloying elements during the preparation process, the strength and wear resistance of the alloy can be greatly improved, and the service life can be significantly extended. The high order and bonding characteristics of the atoms in the alloy give the prepared alloy material higher toughness and strength. Moreover, the coefficient of thermal expansion of the alloy is similar to that of the structural material, and it has excellent microstructure and dimensional stability, making it a very promising material for robot bearings. Attached Figure Description

[0024] Figure 1 The image shown is the XRD pattern of the product obtained in Example 1 of this invention. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. This description is intended to explain the invention and not limit it.

[0026] Example 1

[0027] Step 1, Melting: According to the atomic percentage ratio of Ni: 45%, Ti: 45%, Hf: 7%, Nb: 1%, Si: 1%, C: 1%, each element in the alloy is put into a high-temperature furnace to melt into a liquid metal at a melting temperature of 1600℃.

[0028] Step 2, casting: First, preheat multiple wear-resistant blocks to 200℃, then fix multiple wear-resistant blocks to one side wall of the sand box cavity. After placing a clay core in the center of the sand box cavity, pour the above-mentioned molten metal into the sand box. The casting temperature is 1540℃. After natural cooling, an alloy block is obtained. The cooling time is greater than 12 hours.

[0029] Step 3, Hot Pressing: The alloy block obtained in Step 2 is further densified and homogenized by hot pressing in a high-vacuum hot pressing sintering furnace. The hot pressing heating temperature is 900℃, the heating rate is 20℃ / min, and the holding time is 20min; the pressure is manually applied to 35MPa and held for 15min, and then the pressure is manually reduced as the temperature decreases to obtain the bearing alloy material for the heat exchange automatic inspection robot.

[0030] The hardness of the product obtained in Example 1 was measured using a microhardness tester with a load of 10 N and a holding time of 10 s. The hardness value obtained was the average of 8 data points, and the hardness of the obtained material was 680 Hv.

[0031] Wear rate was measured using a 3D profilometer, and friction experiments were conducted using a friction testing machine (UMT) with GCr15 steel balls as the mating material, a load of 10 N, and a speed of 0.1 m / s. The measured wear rate was within 10... -6 mm 3 On the order of Nm.

[0032] Example 2

[0033] Step 1, Melting: According to the atomic percentage ratio of Ni: 47%, Ti: 43%, Hf: 7%, Nb: 1%, Si: 1%, C: 1%, each element in the alloy is put into a high-temperature furnace to melt into a liquid metal at a melting temperature of 1620℃.

[0034] Step 2, casting: First, preheat multiple wear-resistant blocks to 200℃, then fix multiple wear-resistant blocks to one side wall of the sand box cavity. After placing a clay core in the center of the sand box cavity, pour the above-mentioned molten metal into the sand box. The casting temperature is 1530℃. After natural cooling, an alloy block is obtained. The cooling time is greater than 12 hours.

[0035] Step 3, Hot Pressing: The alloy block obtained in Step 2 is further densified and homogenized by hot pressing in a high-vacuum hot pressing sintering furnace. The hot pressing heating temperature is 900℃, the heating rate is 20℃ / min, and the holding time is 20min; the pressure is manually applied to 35MPa and held for 15min, and then the pressure is manually reduced as the temperature decreases to obtain the bearing alloy material for the heat exchange automatic inspection robot.

[0036] The hardness of the product obtained in Example 1 was measured using a microhardness tester with a load of 10 N and a holding time of 10 s. The hardness value obtained was the average of 8 data points, and the hardness of the obtained material was 700 Hv.

[0037] Wear rate was measured using a 3D profilometer, and friction experiments were conducted using a friction testing machine (UMT) with GCr15 steel balls as the mating material, a load of 10 N, and a speed of 0.1 m / s. The measured wear rate was within 10... -6 mm 3 On the order of Nm.

[0038] Example 3

[0039] Step 1, Melting: According to the atomic percentage ratio of Ni: 50%, Ti: 40%, Hf: 7%, Nb: 1%, Si: 1%, C: 1%, each element in the alloy is put into a high-temperature furnace to melt into a liquid metal at a melting temperature of 1640℃.

[0040] Step 2, casting: First, preheat multiple wear-resistant blocks to 200℃, then fix multiple wear-resistant blocks to one side wall of the sand box cavity. After placing a clay core in the center of the sand box cavity, pour the above-mentioned molten metal into the sand box. The casting temperature is 1550℃. After natural cooling, an alloy block is obtained. The cooling time is greater than 12 hours.

[0041] Step 3, Hot Pressing: The alloy block obtained in Step 2 is further densified and homogenized by hot pressing in a high-vacuum hot pressing sintering furnace. The hot pressing heating temperature is 900℃, the heating rate is 20℃ / min, and the holding time is 20min; the pressure is manually applied to 35MPa and held for 15min, and then the pressure is manually reduced as the temperature decreases to obtain the bearing alloy material for the heat exchange automatic inspection robot.

[0042] The hardness of the product obtained in Example 1 was measured using a microhardness tester with a load of 10 N and a holding time of 10 s. The hardness value obtained was the average of 8 data points, and the hardness of the obtained material was 710 Hv.

[0043] Wear rate was measured using a 3D profilometer, and friction experiments were conducted using a friction testing machine (UMT) with GCr15 steel balls as the mating material, a load of 10 N, and a speed of 0.1 m / s. The measured wear rate was within 10... -6 mm 3 On the order of Nm.

[0044] Example 4

[0045] Step 1, Melting: According to the atomic percentage ratio of Ni: 48%, Ti: 36.4%, Hf: 10%, Nb: 2%, Si: 2%, C: 1.6%, the elements in the alloy are put into a high-temperature furnace to melt into molten metal at a melting temperature of 1640℃.

[0046] Step 2, casting: First, preheat multiple wear-resistant blocks to 220℃, then fix multiple wear-resistant blocks to one side wall of the sand box cavity. After placing a clay core in the center of the sand box cavity, pour the above-mentioned molten metal into the sand box. The casting temperature is 1550℃. After natural cooling, an alloy block is obtained. The cooling time is greater than 12 hours.

[0047] Step 3, Hot Pressing: The alloy block obtained in Step 2 is further densified and homogenized by hot pressing in a high-vacuum hot pressing sintering furnace. The hot pressing heating temperature is 900℃, the heating rate is 20℃ / min, and the holding time is 20min; the pressure is manually applied to 35MPa and held for 15min, and then the pressure is manually reduced as the temperature decreases to obtain the bearing alloy material for the heat exchange automatic inspection robot.

[0048] The hardness of the product obtained in Example 1 was measured using a microhardness tester with a load of 10 N and a holding time of 10 s. The hardness value obtained was the average of 8 data points, and the hardness of the obtained material was 714 Hv.

[0049] Wear rate was measured using a 3D profilometer, and friction experiments were conducted using a friction testing machine (UMT) with GCr15 steel balls as the mating material, a load of 10 N, and a speed of 0.1 m / s. The measured wear rate was within 10... -6 mm 3 On the order of Nm.

[0050] Example 5

[0051] Step 1, Melting: According to the atomic percentage ratio of Ni: 55%, Ti: 40.5%, Hf: 3%, Nb: 0.5%, Si: 0.5%, C: 0.5%, each element in the alloy is put into a high-temperature furnace to melt into a molten metal at a melting temperature of 1640℃;

[0052] Step 2, casting: First, preheat multiple wear-resistant blocks to 220℃, then fix multiple wear-resistant blocks to one side wall of the sand box cavity. After placing a clay core in the center of the sand box cavity, pour the above-mentioned molten metal into the sand box. The casting temperature is 1550℃. After natural cooling, an alloy block is obtained. The cooling time is greater than 12 hours.

[0053] Step 3, Hot Pressing: The alloy block obtained in Step 2 is further densified and homogenized by hot pressing in a high-vacuum hot pressing sintering furnace. The hot pressing heating temperature is 900℃, the heating rate is 20℃ / min, and the holding time is 20min; the pressure is manually applied to 35MPa and held for 15min, and then the pressure is manually reduced as the temperature decreases to obtain the bearing alloy material for the heat exchange automatic inspection robot.

[0054] The hardness of the product obtained in Example 1 was measured using a microhardness tester with a load of 10 N and a holding time of 10 s. The hardness value obtained was the average of 8 data points, and the hardness of the obtained material was 705 Hv.

[0055] Wear rate was measured using a 3D profilometer, and friction experiments were conducted using a friction testing machine (UMT) with GCr15 steel balls as the mating material, a load of 10 N, and a speed of 0.1 m / s. The measured wear rate was within 10... -6 mm 3 On the order of Nm.

[0056] Figure 1 The XRD pattern of the product obtained in the example shows that the introduction of C resulted in the formation of a carbide-reinforced phase in the matrix.

[0057] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. However, obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A bearing alloy material for an automatic heat exchange inspection robot, characterized in that, On an atomic percentage basis, it includes 45%–55% Ni, 40%–45% Ti, 3%–10% Hf, 1%–2% Nb, 0.5%–2% Si, and 0.5%–1.60% C; The method for preparing the bearing alloy material for the heat exchange automatic inspection robot includes the following steps: Step 1: Melt all components in a furnace to form molten metal; Step 2: Pour the molten metal obtained in Step 1 into a container, and after cooling, obtain an alloy block; Step 3: The alloy block obtained in Step 2 is heated to 900°C in a high vacuum hot pressing sintering furnace at a heating rate of 20°C / min and held at that temperature. The pressure is then manually increased to 35MPa and held. After hot pressing, the pressure is manually reduced as the temperature decreases to obtain the bearing alloy material for the heat exchange automatic detection robot.

2. The bearing alloy material for the automatic heat exchange inspection robot according to claim 1, characterized in that, The hardness is 680~714HV, and the wear rate is 10. -6 mm 3 On the order of Nm.

3. A method for preparing bearing alloy material for an automatic heat exchange inspection robot, characterized in that, Includes the following steps: Step 1: Melt all components into a furnace to form molten metal; all components, by atomic percentage, include 45%~55% Ni, 40%~45% Ti, 3%~10% Hf, 1%~2% Nb, 0.5%~2% Si and 0.5%~1.60% C; Step 2: Pour the molten metal obtained in Step 1 into a container, and after cooling, obtain an alloy block; Step 3: The alloy block obtained in Step 2 is heated to 900°C in a high vacuum hot pressing sintering furnace at a heating rate of 20°C / min and held at that temperature. The pressure is then manually increased to 35MPa and held. After hot pressing, the pressure is manually reduced as the temperature decreases to obtain the bearing alloy material for the heat exchange automatic detection robot.

4. The method for preparing bearing alloy material for an automatic heat exchange inspection robot according to claim 3, characterized in that, In step 1, the melting temperature is 1600~1640℃.

5. The method for preparing bearing alloy material for an automatic heat exchange inspection robot according to claim 3, characterized in that, Step 2 specifically involves: preheating several wear-resistant blocks and then fixing them onto the side wall of the sand mold cavity. After placing a core in the center of the sand mold cavity, the molten metal obtained in Step 1 is poured into the sand mold cavity, and the alloy block is obtained after natural cooling.

6. The method for preparing bearing alloy material for an automatic heat exchange inspection robot according to claim 5, characterized in that, Preheat the wear-resistant block to 180-220℃.

7. The method for preparing bearing alloy material for an automatic heat exchange inspection robot according to claim 3, characterized in that, The pouring temperature is 1530~1550℃.

8. The method for preparing bearing alloy material for an automatic heat exchange inspection robot according to claim 5, characterized in that, The natural cooling time is more than 12 hours.

9. The method for preparing bearing alloy material for an automatic heat exchange inspection robot according to claim 3, characterized in that, In step 3, the heat preservation time is 20 minutes.

10. The method for preparing bearing alloy material for an automatic heat exchange inspection robot according to claim 3, characterized in that, In step 3, the pressure holding time is 15 minutes.

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