Creep-thermal fatigue interaction performance testing device

Abstract

The application discloses a kind of creep-thermal fatigue interaction performance test device, including motor mainframe, first sample fixed platform, sample, second sample fixed platform, third force loading rod, heating-cooling platform and stress-strain controller;The output shaft of motor mainframe is connected with first sample fixed platform, the upper end of sample is inserted in the first sample fixed platform, the lower end of sample is inserted in the second sample fixed platform, second sample fixed platform is located on third force loading rod, the middle part of sample is located in heating-cooling platform, first air valve and second air valve are provided on the heating-cooling platform;Strain gauge is pasted on the sidewall of the middle part of sample, stress sensor is provided on third force loading rod, stress-strain controller is connected with stress sensor and strain gauge, the device can realize creep-thermal fatigue interaction test under multi-dimensional stress state.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metal material performance analysis testing and experimental research, and relates to a creep-thermal fatigue interaction performance testing device. BACKGROUND

[0002] Metal parts expand and contract under the action of heating and cooling cycles, and thermal stress and thermal strain are generated under the external constraint of the holding part. For some large cross-section size parts, even without the constraint of the holding part, due to the temperature difference between the inner and outer surfaces of the part, the inner and outer expansion and contraction are inconsistent, and thermal stress and thermal strain are also generated. The thermal stress and thermal strain caused by such temperature cycles result in thermal fatigue damage of the part. The fatigue caused by temperature cycles with the constraint of the holding part or mechanical cyclic load is called thermal-mechanical fatigue. Most high-temperature parts in engineering (turbine rotor, large cast steel parts, drum, thick-walled header, etc.) are subjected to thermal-mechanical fatigue.

[0003] The iron-nickel-based high-temperature alloy turbine rotor is a large-scale integral forging, which mainly bears thermal-mechanical fatigue during operation. At the same time, the rotor forging is subjected to creep damage at service temperature, and the damage mechanism is thermal-mechanical fatigue-creep interaction damage. With the acceleration of clean energy transformation, it is necessary to increase the consumption capacity of new energy such as wind and light at the transmission and distribution end and maintain the stability of the power grid. The flexibility of thermal power reconstruction increases the frequency of starting and stopping or large changes in load, which makes the rotor bear severe temperature changes and alternating thermal stress, promotes the interaction of thermal fatigue and creep, deteriorates the material properties, accelerates the damage of the material, and shortens the service life of the rotor forging. In the units participating in peak regulation operation, the performance damage caused by the interaction of thermal fatigue and creep in thick-walled parts (such as turbine rotors, large cast steel parts, drums, thick-walled headers, etc.) is increasingly prominent. The performance of the material under the combined action of creep and thermal fatigue depends not only on the creep performance or fatigue performance of the material, but also on the interaction between creep and thermal fatigue. The damage caused by the interaction of creep and thermal fatigue will become an important factor limiting the safe service life of such equipment.

[0004] At present, the failure research of thick-walled components in thermal power units mainly focuses on the creep-fatigue interaction, and the existing test devices are all creep-fatigue testing machines, that is, the thermal fatigue state in service is simulated through high-temperature low-cycle fatigue test conditions. The thermal fatigue is similar to the high-temperature low-cycle fatigue in that the cycle frequency is very low, but the damage mechanism of the thermal fatigue is much more complex than that of the high-temperature low-cycle fatigue, and the thermal fatigue is more likely to cause local cumulative plastic deformation at the position with the highest temperature and the greatest restraint than the high-temperature low-cycle fatigue, so under the condition of the same macroscopic plastic deformation, the thermal fatigue life is obviously lower than the high-temperature low-cycle fatigue. At present, the existing test devices are basically low-cycle fatigue testing machines under high-temperature mechanical stress or independent creep testing machines, and it is difficult to truly simulate the actual damage mechanism of large cross-section thick-walled components such as steam turbine rotor, high-pressure inner cylinder, automatic main steam valve, and boiler drum and steam-water separator. As for the creep and thermal fatigue interaction, the problem under multi-dimensional stress state, there is no relevant creep-thermal fatigue test device that can directly test and obtain relevant data. SUMMARY

[0005] The present application aims to overcome the above-mentioned shortcomings of the prior art, and provides a creep-thermal fatigue interaction performance test device, which can realize the creep-thermal fatigue interaction test under multi-dimensional stress state.

[0006] To achieve the above-mentioned purpose, the creep-thermal fatigue interaction performance test device comprises a motor main machine, a first sample fixing table, a sample, a second sample fixing table, a third force loading rod, a heating-cooling table and a stress-strain controller.

[0007] The output shaft of the motor main machine is connected with the first sample fixing table, the upper end of the sample is inserted into the first sample fixing table, the lower end of the sample is inserted into the second sample fixing table, the second sample fixing table is located on the third force loading rod, the middle part of the sample is located in the heating-cooling table, and the heating-cooling table is provided with a first air valve and a second air valve.

[0008] The side wall of the middle part of the sample is pasted with a strain gauge, the third force loading rod is provided with a stress sensor, and the stress-strain controller is connected with the stress sensor and the strain gauge.

[0009] It also comprises a first connecting rod and a second connecting rod, the output shaft of the motor main machine is connected with the upper end of the first connecting rod, the lower end of the first connecting rod is connected with the upper end of the second connecting rod, and the lower end of the second connecting rod is connected with the first sample fixing table.

[0010] The temperature controller is connected with the thermocouple, the first air knife cooling device, the second air knife cooling device and the heating coil.

[0011] The heating coil is sleeved on the sample.

[0012] The first sample fixing table and the second sample fixing table clamp the sample through a mortise and tenon structure.

[0013] The stress-strain controller is connected with the stress sensor through a stress sensor terminal post and is connected with the strain gauge through a strain gauge terminal post.

[0014] The temperature controller is connected with one end of the heating coil through an upper coil terminal post and is connected with the other end of the heating coil through a lower coil terminal post.

[0015] The temperature controller is connected with the thermocouple through a thermocouple terminal post.

[0016] The temperature controller is connected with the first air knife cooling device and the second air knife cooling device through an air knife terminal post.

[0017] The first force loading rod, the second force loading rod and the fourth force loading rod are further included.

[0018] The lower end of the first force loading rod and the lower end of the second force loading rod are connected with the fourth force loading rod, and the upper end of the first force loading rod and the upper end of the second force loading rod are connected with the motor main machine.

[0019] The third force loading rod is fixed between the first force loading rod and the second force loading rod, and the motor main machine is located above the third force loading rod.

[0020] The present application has the following beneficial effects:

[0021] In the operation of the creep-thermal fatigue interaction performance test device, the output shaft of the motor main machine is connected with the first sample fixing table, the upper end of the sample is inserted into the first sample fixing table, the lower end of the sample is inserted into the second sample fixing table, the second sample fixing table is located on the third force loading rod, a constant creep stress is applied to the sample by the motor main machine, the middle part of the sample is located in the heating-cooling table, the temperature of the environment where the sample is located is adjusted by the heating-cooling table, and the creep-thermal fatigue interaction test under a multi-dimensional stress state is realized. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The present application is a structural diagram.

[0023] Figure 2Structure diagram of sample 10.

[0024] Wherein, 1 is the first force loading rod, 2 is the second force loading rod, 3 is the third force loading rod, 4 is the fourth force loading rod, 5 is the motor mainframe, 6 is the first connecting rod, 7 is the second connecting rod, 8 is the first sample fixing table, 9 is the second sample fixing table, 10 is the sample, 11 is the heating-cooling table, 12 is the heating coil, 13 is the first air knife air cooling device, 14 is the second air knife air cooling device, 15 is the first air valve, 16 is the second air valve, 17 is the thermocouple, 18 is the upper coil terminal post, 19 is the lower coil terminal post, 20 is the air knife terminal post, 21 is the thermocouple terminal post, 22 is the stress sensor, 23 is the strain gauge, 24 is the stress sensor terminal post, 25 is the strain gauge terminal post, 26 is the stress-strain controller, 27 is the temperature controller. DETAILED DESCRIPTION

[0025] In order to make the personnel in the technical field better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments, and are not intended to limit the scope of the present application. In addition, in the following description, the description of the known structures and technologies is omitted to avoid unnecessary confusion of the concepts disclosed in the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts should belong to the scope of protection of the present application.

[0026] The structural schematic diagram according to the disclosed embodiments of the present application is shown in the drawings. These drawings are not drawn to scale, in which some details are enlarged for the purpose of clear expression, and some details can be omitted. The shapes of various regions, layers and their relative size and positional relationship shown in the drawings are only exemplary, and in actuality, there can be deviations due to manufacturing tolerances or technical limitations, and the regions / layers with different shapes, sizes and relative positions can be additionally designed by those skilled in the art according to actual needs.

[0027] Reference Figure 1 and Figure 2The creep-thermal fatigue interaction performance testing device comprises a first force loading rod 1, a second force loading rod 2, a third force loading rod 3, a fourth force loading rod 4, a motor main machine 5, a first connecting rod 6, a second connecting rod 7, a first sample fixing table 8, a second sample fixing table 9, a sample 10, a heating-cooling table 11, a heating coil 12, a first air knife air cooling device 13, a second air knife air cooling device 14, a first air valve 15, a second air valve 16, a thermocouple 17, an upper coil terminal 18, a lower coil terminal 19, an air knife terminal 20, a thermocouple terminal 21, a stress sensor 22, a strain gauge 23, a stress sensor terminal 24, a strain gauge terminal 25, a stress-strain controller 26 and a temperature controller 27.

[0028] The lower end of the first force loading rod 1 and the lower end of the second force loading rod 2 are connected with the fourth force loading rod 4, and the upper end of the first force loading rod 1 and the upper end of the second force loading rod 2 are connected with the motor main machine 5.

[0029] The third force loading rod 3 is fixed between the first force loading rod 1 and the second force loading rod 2, the motor main machine 5 is located above the third force loading rod 3, the output shaft of the motor main machine 5 is connected with the upper end of the first connecting rod 6, the lower end of the first connecting rod 6 is connected with the upper end of the second connecting rod 7, the lower end of the second connecting rod 7 is connected with the first sample fixing table 8, the upper end of the sample 10 is inserted into the first sample fixing table 8, the lower end of the sample 10 is inserted into the second sample fixing table 9, the second sample fixing table 9 is located on the third force loading rod 3, the middle part of the sample 10 is located in the heating-cooling table 11, and the heating-cooling table 11 is provided with the first air valve 15 and the second air valve 16.

[0030] The heating-cooling table 11 is provided with the thermocouple 17 and the heating coil 12, the two sides of the heating-cooling table 11 are respectively provided with the first air knife air cooling device 13 and the second air knife air cooling device 14, the side wall of the middle part of the sample 10 is pasted with the strain gauge 23, and the heating coil 12 is sleeved on the sample 10.

[0031] The third force loading rod 3 is provided with the stress sensor 22, the stress-strain controller 26 is connected with the stress sensor 22 and the strain gauge 23, and the temperature controller 27 is connected with the thermocouple 17, the first air knife air cooling device 13, the second air knife air cooling device 14 and the heating coil 12.

[0032] Specifically, the stress-strain controller 26 is connected with the stress sensor 22 through the stress sensor terminal 24, and the stress-strain controller 26 is connected with the strain gauge 23 through the strain gauge terminal 25; the temperature controller 27 is connected with one end of the heating coil 12 through the upper coil terminal 18, and the temperature controller 27 is connected with the other end of the heating coil 12 through the lower coil terminal 19, and the temperature controller 27 is connected with the thermocouple 17 through the thermocouple terminal 21; the temperature controller 27 is connected with the first air knife air cooling device 13 and the second air knife air cooling device 14 through the air knife terminal 20.

[0033] It should be noted that the first sample fixing table 8 and the second sample fixing table 9 clamp the sample 10 through a mortise and tenon structure, the middle part of the sample 10 is completely wrapped in the heating-cooling table 11, the sample 10 is fixed at room temperature, the motor host 5 is operated to apply a constant creep stress, in the process of applying the stress, the stress sensor 22 and the stress-strain controller 26 are used for observation and control, the heating coil 12 is heated to the lowest temperature in the cycle, at this time, the heating speed is relatively fast, after the temperature is stable, heating is continued, the temperature cycle period starts, that is, heating-heat preservation-cooling, at this time, the heating rate, the heat preservation time and the cooling rate are determined according to the test requirements. During the cooling process, the first air valve 15 and the second air valve 16 are first opened, and the first air knife air cooling device 13 and the second air knife air cooling device 14 are also opened, the cooling rate is adjusted through the cooperation of the air valve and the air knife, and the sample 10 is uniformly cooled. In the whole cycle period, the strain gauge 23 and the stress sensor 22 record the stress and strain curves of the sample 10 in the test period through the stress-strain controller 26, and the stress-strain data under the interaction of creep and thermal fatigue are obtained.

[0034] In the present application, atmosphere protection can also be carried out, that is, the first air valve 15 and the second air valve 16 are used to continuously inject protective gas into the heating-cooling table 11 to protect the sample 10, and a high-temperature-resistant micro monitor can also be arranged at the terminal to observe the state of the sample 10 in multiple cycle periods, without the need of repeatedly sampling for observation.

[0035] Example one

[0036] For the case of less cycle times, without the need for anti-oxidation protection, the protective gas can not be injected. The specific process is as follows: taking the iron-nickel based high-temperature alloy rotor forging processing sample 10, fixing the sample 10 in the heating coil 12, applying a constant creep stress and installing the strain gauge 23, then powering the heating coil 12, controlling by the temperature controller 27, heating for 4 min, raising the temperature to 550℃, which is the lowest temperature in the temperature cycle, continuing to heat, heating for 10 min, heating to the highest temperature 650℃, keeping for 40 min, then opening the first gas valve 15 and the second gas valve 16, and cooling to 550℃ by the air knife, and the cooling time is 10 min. The stress-strain curve of the sample 10 under the stress-strain controller 26 is recorded, which is the stress-strain data under the interaction of creep-thermal fatigue, and the heating and cooling process is repeated until the required cycle times are reached, the power is cut off, and the sample 10 is taken out.

[0037] Example Two

[0038] For the case of more cycle times, it is inconvenient to repeatedly take samples for observation, and the protective gas can be injected for anti-oxidation protection of the sample 10. The specific process is as follows: taking the iron-nickel based high-temperature alloy rotor forging processing sample 10, fixing the sample 10 in the heating coil 12, applying a constant creep stress and installing the strain gauge 23, connecting the high-temperature micro monitor, and opening the first gas valve 15 and the second gas valve 16 to continuously inject protective gas in the heating-cooling table 11, when the protective gas is sufficient, powering the heating coil 12, controlling by the temperature controller 27, heating for 4 min, raising the temperature to 550℃, which is the lowest temperature in the temperature cycle, continuing to heat, heating for 10 min, heating to the highest temperature 650℃, keeping for 40 min, then opening the air knife for air cooling, cooling to 550℃, and the cooling time is 10 min. In the test temperature cycle, the state of the sample 10 in multiple cycle periods is observed by the micro monitor, and the stress-strain curve of the sample under the stress-strain controller 26 is recorded, which is the stress-strain data under the interaction of creep-thermal fatigue, and the heating and cooling process is repeated until the required cycle times are reached, the power is cut off, and the sample 10 is taken out. During the whole process, the protective gas consumption is large due to long-term gas injection.

[0039] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit it. Although the present application has been described in detail with reference to the above examples, those skilled in the art should understand that the specific embodiments of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the present application, and any modification or equivalent replacement without departing from the spirit and scope of the present application should be covered in the protection scope of the claims of the present application.

Claims

1. A creep-thermal fatigue interaction performance testing device, characterized in that, The motor main machine (5), the first sample fixing table (8), the sample (10), the second sample fixing table (9), the third force loading rod (3), the heating-cooling table (11) and the stress-strain controller (26) are connected. The output shaft of the motor main machine (5) is connected with the first sample fixing table (8), the upper end of the sample (10) is inserted into the first sample fixing table (8), the lower end of the sample (10) is inserted into the second sample fixing table (9), the second sample fixing table (9) is located on the third force loading rod (3), the middle part of the sample (10) is located in the heating-cooling table (11), and the heating-cooling table (11) is provided with the first air valve (15) and the second air valve (16). The side wall of the middle part of the sample (10) is pasted with the strain gauge (23), the third force loading rod (3) is provided with the stress sensor (22), and the stress-strain controller (26) is connected with the stress sensor (22) and the strain gauge (23). The heating-cooling table (11) is provided with the thermocouple (17) and the heating coil (12), the two sides of the heating-cooling table (11) are respectively provided with the first air knife cooling device (13) and the second air knife cooling device (14), and the temperature controller (27) is connected with the thermocouple (17), the first air knife cooling device (13), the second air knife cooling device (14) and the heating coil (12). The heating coil (12) is sleeved on the sample (10).

2. The creep-thermal fatigue interaction property testing apparatus according to claim 1, characterized by, The output shaft of the motor main machine (5) is connected with the upper end of the first connecting rod (6), the lower end of the first connecting rod (6) is connected with the upper end of the second connecting rod (7), and the lower end of the second connecting rod (7) is connected with the first sample fixing table (8).

3. The creep-thermal fatigue interaction property testing apparatus according to claim 1, characterized by, The first sample fixing table (8) and the second sample fixing table (9) clamp the sample (10) through the mortise and tenon structure.

4. The creep-thermal fatigue interaction property testing apparatus according to claim 1, characterized by, The stress-strain controller (26) is connected with the stress sensor (22) through the stress sensor terminal post (24) and connected with the strain gauge (23) through the strain gauge terminal post (25).

5. The creep-thermal fatigue interaction property testing apparatus according to claim 1, characterized by, The temperature controller (27) is connected with one end of the heating coil (12) through the coil upper terminal post (18) and connected with the other end of the heating coil (12) through the coil lower terminal post (19).

6. The creep-thermal fatigue interaction property testing apparatus according to claim 1, characterized by, The temperature controller (27) is connected with the thermocouple (17) through the thermocouple terminal post (21).

7. The creep-thermal fatigue interaction property testing apparatus according to claim 1, characterized by, The temperature controller (27) is connected with the first air knife cooling device (13) and the second air knife cooling device (14) through the air knife terminal post (20).

8. The creep-thermal fatigue interaction property testing apparatus according to claim 1, characterized by, The first force loading rod (1), the second force loading rod (2) and the fourth force loading rod (4) are further included. The lower end of the first force loading rod (1) and the lower end of the second force loading rod (2) are connected with the fourth force loading rod (4), and the upper end of the first force loading rod (1) and the upper end of the second force loading rod (2) are connected with the motor main machine (5). The third force loading rod (3) is fixed between the first force loading rod (1) and the second force loading rod (2), and the motor main machine (5) is located above the third force loading rod (3).

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