A bulging test device for testing creep properties of metal sheets

Abstract

The invention discloses a swelling test device for creep performance test of metal sheets, comprising a frame, a clamping mechanism, a temperature-controlled furnace, a pressure-loading mechanism, a deformation measuring mechanism and a computer. The frame is provided with a temperature-controlled furnace, a clamping mechanism is provided in the temperature-controlled furnace, the clamping mechanism is used to clamp a test specimen, the pressure-loading mechanism applies expansion pressure to the test specimen through a medium, the deformation measuring mechanism is provided above the test specimen, and the temperature-controlled furnace, the pressure-loading mechanism and the deformation measuring mechanism are electrically connected to the computer respectively. The test device of the invention can test the mechanical properties of the test specimen at high temperature, the test temperature is uniform, the operation is convenient, and the cost is low and the safety is good.

Description

Technical Field

[0001] The invention relates to the technical field of swelling test, in particular to a swelling test device for testing creep performance of metal sheets. Background Art

[0002] In the fields of aerospace, nuclear power, petrochemicals, etc., pressure-bearing equipment or other metal components used under high temperature, high pressure, irradiation and other conditions will gradually deteriorate and be damaged as the service time increases. The mechanical properties of the materials gradually degrade, which may lead to failure of pressure-bearing equipment or other metal components, causing safety accidents and causing significant economic losses. In order to timely understand the degree of degradation of the mechanical properties of materials, the traditional solution is to cut a certain amount of material from the in-service equipment and process it into standard specimens for performance testing. Although the results are relatively accurate and reliable, this method has a large specimen size and requires more material to be cut, which is easy to damage the equipment and cannot be applied in many occasions. Although non-destructive testing methods such as indentation can avoid damage to the integrity of the equipment, the test items and test results of its mechanical properties have obvious limitations. It is impossible to obtain a complete mechanical property curve and it cannot be used at higher temperatures. Therefore, it is impossible to give accurate and comprehensive quantitative data on the mechanical properties of materials at high temperatures, such as creep characteristics and endurance strength.

[0003] In order to solve the key problem of mechanical property testing of in-service equipment materials at high temperatures, a micro-specimen test method, namely the small punch test method, was proposed in the early 1980s. It can test some mechanical properties of materials at high temperatures, and has achieved certain research results in yield strength, tensile strength, ductile-brittle transition temperature, creep characteristics and fracture toughness testing. However, this method also has obvious shortcomings, namely, it is impossible to maintain stable loading on the test specimen. In addition, due to the influence of factors such as friction, centering error, and deformation of the punch itself, it is difficult to establish an ideal relationship between material properties and force-displacement curves in theory. Multiple repeated tests are required. The high-temperature creep characteristics, endurance strength and other results obtained from the tests are also mainly dependent on the establishment of empirical correlations with traditional test methods, resulting in different empirical correlation formulas obtained by different researchers, and practical applications are limited.

[0004] In summary, how to conduct a limited number of micro-specimen tests to accurately know the mechanical properties of damaged materials under high temperature conditions and then obtain reliable remaining life is the key to the safe operation and reliable life extension of high-temperature components, and has also become a technical problem that needs to be urgently solved by technical personnel in this field. Summary of the invention

[0005] The purpose of the present invention is to provide a bulging test device for creep performance testing of metal sheets to solve the problems existing in the above-mentioned prior art, so that the mechanical property test of the test piece in a high temperature environment is easy to operate and the experimental data is reliable.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] The present invention provides a bulging test device for creep performance testing of metal sheets, comprising a frame, a clamping mechanism, a temperature-controlled furnace, a pressure-loading mechanism, a deformation measuring mechanism and a computer, wherein the temperature-controlled furnace is arranged on the frame, the clamping mechanism is arranged in the temperature-controlled furnace, the clamping mechanism is used to clamp a test specimen, the pressure-loading mechanism applies expansion pressure to the test specimen through a medium, the deformation measuring mechanism is arranged above the test specimen, and the temperature-controlled furnace, the pressure-loading mechanism and the deformation measuring mechanism are electrically connected to the computer respectively.

[0008] Preferably, the frame includes a base, support columns, columns and cross beams, a pair of columns are symmetrically arranged on both sides of the base, a support column is arranged in the middle, the columns are higher than the support columns, the cross beam is connected to the top ends of the two columns, and the clamping mechanism is threadedly connected to the support column.

[0009] Preferably, the clamping mechanism includes a support ring, a clamping pressure ring and a stabilizing pressure ring, the stabilizing pressure ring is sleeved on the upper end of the clamping pressure ring, the support ring is sleeved on the lower end, and the lower end of the clamping pressure ring is threadedly connected to the support column, and the test specimen is arranged between the support ring and the clamping pressure ring.

[0010] Preferably, a groove is provided at both the upper and lower ends of the clamping pressure ring, and the two grooves are connected by a stepped hole which is smaller at the top and larger at the bottom. A groove is also provided at the lower opening of the stabilizing pressure ring. The side wall of the stabilizing pressure ring is connected to the side wall of the clamping pressure ring by bolts. A pressurizing groove is provided above the support ring, and the test specimen is placed or welded on the upper end surface of the support ring.

[0011] Preferably, the temperature-controlled furnace includes a heating furnace cavity, a temperature sensor and a supporting cantilever, the supporting column passes through the bottom surface of the heating furnace cavity, the temperature sensor is arranged inside the heating furnace cavity, the heating furnace cavity is fixed to one of the columns through a multi-link hinged supporting cantilever, and the temperature sensor is electrically connected to the computer.

[0012] Preferably, the heating furnace chamber is a double-open atmospheric furnace, the maximum heating temperature of the heating furnace chamber is 650°C, the upper, middle and lower parts of the inner wall of the heating furnace chamber are respectively provided with a temperature sensor, and the large hole of the stepped hole is provided with a temperature sensor.

[0013] Preferably, a safety protection mechanism is provided on the heating furnace chamber, and the safety protection mechanism includes a gas cylinder and a valve. The gas cylinder is connected to the heating furnace chamber through a pipeline, the valve is provided on the pipeline, and the gas cylinder contains inert gas.

[0014] Preferably, the deformation measuring mechanism includes a displacement guide rod and an extensometer, the lower end of the displacement guide rod sequentially passes through the upper surface of the heating furnace chamber, the stepped holes of the stabilizing pressure ring and the clamping pressure ring and contacts with the upper surface of the test specimen, the column is connected to the extensometer, the extensometer contacts with the displacement guide rod and is electrically connected to the computer.

[0015] Preferably, each of the uprights is connected to an extensometer via a support plate, the displacement guide rod is T-shaped and the cross bar at the upper end respectively contacts the two extensometers, and the vertical bar of the displacement guide rod is a stepped shaft with a smaller bottom and a larger top.

[0016] Preferably, the pressure loading mechanism includes a hydraulic or pneumatic piston pump, a medium delivery pipe and a pressure sensor, one end of the medium delivery pipe passes through the base, the support column is connected to the pressurizing groove, and the other end is connected to the piston pump. The pressure sensor is arranged on the medium delivery pipe, and the pressure sensor is electrically connected to the computer.

[0017] Compared with the prior art, the present invention has achieved the following technical effects:

[0018] The test device of the present invention can test the mechanical properties of a test piece at high temperature, has uniform test temperature, is easy to operate, and has low cost and good safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a structural schematic diagram of a bulging test device for testing creep performance of a metal sheet according to the present invention;

[0021] Figure 2 It is a structural schematic diagram of the frame in the present invention;

[0022] Figure 3 It is a structural schematic diagram of the clamping mechanism in the present invention;

[0023] Figure 4 It is a schematic diagram of the structure of the support ring in the present invention;

[0024] Wherein: 100-bulging test device for creep property test of metal sheet, 1-base, 2-column, 3-heating furnace chamber, 4-support cantilever, 5-displacement guide rod, 6-extensometer, 7-medium delivery pipe, 8-support ring, 9-test specimen, 10-clamping pressure ring, 11-stabilizing pressure ring, 12-bolt, 13-weld, 14-support column, 15-temperature sensor, 16-crossbeam, 17-gas cylinder, 18-piston pump, 19-pressure sensor, 20-computer. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The purpose of the present invention is to provide a bulging test device for creep performance testing of metal sheets to solve the problems existing in the prior art and make the mechanical performance testing of test pieces in a high temperature environment easy to operate and the experimental data reliable.

[0027] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] like Figures 1 to 4 As shown: This embodiment provides a bulging test device 100 for creep performance testing of metal sheets, including a frame, a clamping mechanism, a temperature-controlled furnace, a pressure-loading mechanism, a deformation measuring mechanism and a computer 20. The frame is provided with a temperature-controlled furnace, and a clamping mechanism is provided in the temperature-controlled furnace. The clamping mechanism is used to clamp the test specimen 9. The pressure-loading mechanism applies expansion pressure to the test specimen 9 through a medium. The deformation measuring mechanism is arranged above the test specimen 9. The temperature-controlled furnace, the pressure-loading mechanism and the deformation measuring mechanism are electrically connected to the computer 20 respectively.

[0029] The frame includes a base 1, a support column 14, a column 2 and a crossbeam 16. A pair of columns 2 are symmetrically arranged on both sides of the base 1, and a support column 14 is arranged in the middle. The column 2 is higher than the support column 14. The crossbeam 16 is connected to the top of the two columns 2 to ensure the stability of the frame. A clamping mechanism is threadedly connected to the support column 14.

[0030] The clamping mechanism includes a support ring 8, a clamping ring 10 and a stabilizing ring 11. The upper end of the clamping ring 10 is sleeved with a stabilizing ring 11, and the lower end is sleeved with a support ring 8. The lower end of the clamping ring 10 is threadedly connected to the support column 14, and a test specimen 9 is arranged between the support ring 8 and the clamping ring 10. A groove is arranged at both the upper and lower ends of the clamping ring 10, and the two grooves are connected through a stepped hole with a small upper part and a large lower part. A groove is also arranged at the lower end of the stabilizing ring 11. The side wall of the stabilizing ring 11 is connected to the side wall of the clamping ring 10 by bolts 12. A pressurizing groove is arranged above the support ring 8. Preferably, the test specimen 9 is placed or welded on the upper end surface of the support ring 8. If welding is adopted, a circle of weld 13 is formed to seal the pressurizing groove, which can be applied to larger pressure test experiments. The test specimen 9 is welded or simply pressed against the support ring 8 to prevent leakage of the pressurized medium, so that the test specimen 9 in the heating furnace chamber 3 is always in a stable pressurized state during the test and reaches the load state required by the test.

[0031] The temperature control furnace includes a heating furnace chamber 3, a temperature sensor 15 and a support cantilever 4. The support column 14 passes through the bottom surface of the heating furnace chamber 3. The temperature sensor 15 is arranged inside the heating furnace chamber 3. The heating furnace chamber 3 is fixed on one of the columns 2 through a multi-link hinged support cantilever 4, and can rotate around the column 2. It is very convenient to install the test specimen 9. The temperature sensor 15 is electrically connected to the computer 20 to monitor the temperature change in real time. The heating furnace chamber 3 is a double-open atmospheric furnace, which is easy to open and close, quick to open and close, and easy to operate. The clamping mechanism and the test specimen 9 in the furnace are very convenient to install and take and place, which is convenient for observing the state of the test process; the furnace wall is used to provide heating, the heating temperature is uniform, and it is designed to be cylindrical, so that the distance between the furnace wall and the test specimen 9 is kept within an equidistant or small error range, thereby making the circumferential temperature of the test specimen 9 more balanced. The maximum heating temperature of the heating furnace chamber 3 is 650°C. A temperature sensor 15 is respectively arranged at the upper, middle and lower parts of the inner wall of the heating furnace chamber 3. A temperature sensor 15 is arranged in the large hole of the stepped hole, which can detect the actual temperature of the test specimen 9 to make the experimental data more accurate.

[0032] A safety protection mechanism is provided on the heating furnace chamber 3, and the safety protection mechanism includes a gas cylinder 17 and a valve. The gas cylinder 17 is connected to the heating furnace chamber 3 through a pipeline, and a valve is provided on the pipeline. The gas cylinder 17 contains an inert gas. In this embodiment, the protective gas is nitrogen or an inert gas, which can not only protect the upper surface of the test specimen 9 from high-temperature oxidation damage, but also prevent the dangers of combustion, explosion, etc. that may occur when the test pressure medium is a flammable and explosive medium.

[0033] The deformation measuring mechanism includes a displacement guide rod 5 and an extensometer 6. The lower end of the displacement guide rod 5 passes through the upper surface of the heating furnace chamber 3, the stepped holes of the stabilizing pressure ring 11 and the clamping pressure ring 10 in sequence (with clearance fit to facilitate the displacement guide rod 5 to slide up and down) and contacts the upper surface of the test specimen 9. The column 2 is connected with the extensometer 6. The extensometer 6 contacts the displacement guide rod 5 and is electrically connected to the computer 20. The measurement and use of the extensometer 6 improve the detection accuracy of the test data. Each column 2 is connected to an extensometer 6 through a support plate. The displacement guide rod 5 is T-shaped and the crossbar at the upper end conflicts with the two extensometers 6 respectively. The vertical rod of the displacement guide rod 5 is a stepped shaft with a small bottom and a large top. The use of a round rod can have sufficient rigidity at high temperatures and can cooperate well with the test specimen 9, so that the displacement guide rod 5 can slide up and down freely to avoid inaccurate measurement due to friction and other problems; the outer diameter of the vertical rod below the stabilizing pressure ring 11 is 4mm, and the outer diameter above it is 8mm, so as to improve the rigidity of the vertical rod and reduce the influence of the high-temperature deformation of the vertical rod on the experimental data. Among them, the support plate and the support cantilever 4 are detachably connected to the column 2 through a pipe clamp and a bolt 12, which is convenient for disassembly and replacement, or height adjustment.

[0034] The pressure loading mechanism includes a hydraulic or pneumatic piston pump 18, a medium delivery pipe 7 and a pressure sensor 19. One end of the medium delivery pipe 7 passes through the base 1, the support column 14 and is connected to the pressure tank, and the other end is connected to the piston pump 18. The medium delivery pipe 7 is provided with a pressure sensor 19, and the pressure sensor 19 is electrically connected to the computer 20. Among them, the medium delivery pipe 7 is connected by a tapered pipe thread connection, which has good sealing and no leakage of the pressure medium. In this embodiment, a liquid or gas medium is passed through the pressure tank to load the middle area of ​​the test specimen 9 with pressure. The load is uniform and stable, without the influence of friction, and the mechanical analysis results are significantly better than those of other similar test devices. At the same time, the mechanical properties of the material at high temperature can be tested.

[0035] The specific operation of the swelling test device 100 for testing the creep performance of metal sheets in this embodiment is as follows:

[0036] At the beginning of the test, the test specimen 9 is first loaded into the clamping mechanism, the gas cylinder 17 is opened to introduce the protective gas, and the temperature-controlled furnace is heated to the specified temperature. Then, the pressure medium is pressurized by the piston pump 18, and then the test specimen 9 on the pressurized groove is pressurized to expand, and then the displacement guide rod 5 above the test specimen 9 changes in height, thereby acting on the extensometer 6 to measure the deformation of the test specimen 9, and transmit the signal to the computer 20 for data acquisition and processing, and analyze the displacement and pressure changes of the bulging specimen over time, and then calculate the mechanical properties of the test specimen 9 at high temperature, such as creep characteristics, endurance strength and other data.

[0037] The present specification uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A bulging test device for creep performance testing of metal sheets, characterized in that: The device comprises a frame, a clamping mechanism, a temperature-controlled furnace, a pressure-loading mechanism, a deformation measuring mechanism and a computer. The frame is provided with the temperature-controlled furnace, the temperature-controlled furnace is provided with the clamping mechanism, the clamping mechanism is used to clamp a test specimen, the pressure-loading mechanism applies expansion pressure to the test specimen through a medium, the deformation measuring mechanism is provided above the test specimen, and the temperature-controlled furnace, the pressure-loading mechanism and the deformation measuring mechanism are electrically connected to the computer respectively. The clamping mechanism comprises a supporting ring, a clamping ring and a stabilizing ring, wherein the upper and lower ends of the clamping ring are both provided with a groove, and the two grooves are connected through a stepped hole which is smaller at the top and larger at the bottom, and the lower opening of the stabilizing ring is also provided with a groove, and the side wall of the stabilizing ring is connected with the side wall of the clamping ring by bolts, and a pressurizing groove is provided above the supporting ring, and the test specimen is placed or welded on the upper end surface of the supporting ring; The deformation measuring mechanism comprises a displacement guide rod and an extensometer. The lower end of the displacement guide rod sequentially passes through the upper surface of the heating furnace chamber of the temperature-controlled furnace, the stepped holes of the stabilizing pressure ring and the clamping pressure ring and contacts with the upper surface of the test specimen. The extensometer is connected to the column of the frame, and the extensometer contacts with the displacement guide rod and is electrically connected to the computer. Each of the columns is connected with an extensometer through a supporting plate. The displacement guide rod is T-shaped and the cross bar at the upper end contacts with two extensometers respectively. The vertical bar of the displacement guide rod is a stepped shaft with a small lower part and a large upper part.

2. The bulging test device for creep performance testing of metal sheets according to claim 1, characterized in that: The frame includes a base, support columns, columns and crossbeams. A pair of columns are symmetrically arranged on both sides of the base, and a support column is arranged in the middle. The columns are higher than the support columns. The crossbeam is connected to the top ends of the two columns, and the clamping mechanism is threadedly connected to the support columns.

3. The swelling test device for creep performance testing of metal sheets according to claim 2, characterized in that: The upper end of the clamping ring is sleeved with the stabilizing ring, the lower end is sleeved with the supporting ring, and the lower end of the clamping ring is threadedly connected to the supporting column, and the testing specimen is arranged between the supporting ring and the clamping ring.

4. The bulging test device for creep performance testing of metal sheets according to claim 2, characterized in that: The temperature-controlled furnace includes a heating furnace chamber, a temperature sensor and a supporting cantilever. A safety protection mechanism is arranged on the heating furnace chamber. The safety protection mechanism includes a gas cylinder and a valve. The gas cylinder is connected to the heating furnace chamber through a pipeline. The valve is arranged on the pipeline. The gas cylinder contains inert gas.

5. The swelling test device for creep performance testing of metal sheets according to claim 4, characterized in that: The support column passes through the bottom surface of the heating furnace cavity, the temperature sensor is arranged inside the heating furnace cavity, the heating furnace cavity is fixed to one of the columns through a multi-link hinged support cantilever, and the temperature sensor is electrically connected to the computer.

6. The swelling test device for creep performance testing of metal sheets according to claim 5, characterized in that: The heating furnace chamber is a double-open atmospheric furnace, the maximum heating temperature of the heating furnace chamber is 650°C, the upper, middle and lower parts of the inner wall of the heating furnace chamber are respectively provided with a temperature sensor, and the large hole of the stepped hole is provided with a temperature sensor.

7. The swelling test device for creep performance testing of metal sheets according to claim 2, characterized in that: The pressure loading mechanism includes a hydraulic or pneumatic piston pump, a medium delivery pipe and a pressure sensor. One end of the medium delivery pipe passes through the base, the support column is connected to the pressurizing groove, and the other end is connected to the piston pump. The pressure sensor is arranged on the medium delivery pipe, and the pressure sensor is electrically connected to the computer.

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