Method for testing thermal shock resistance of special glass

Abstract

The invention discloses a method for testing thermal shock resistance of special glass, and relates to the technical field of glass performance testing. The method comprises the following steps: preparing a sample and carrying out pre-annealing treatment; setting test parameters; alternately transferring the sample between a high-temperature furnace and a low-temperature tank, wherein the low-temperature tank adopts a liquid nitrogen refrigeration technology, so that the test temperature can be extended to-150 DEG C; dynamic change and temperature field distribution of the sample in the testing process are monitored in real time through an industrial high-speed camera and a thermal imager; and after the test is completed, carrying out surface topography inspection on the sample, and carrying out qualification judgment and performance grade evaluation according to a preset judgment standard in combination with dynamic monitoring data. The problems of limited low-temperature test range and insufficient temperature control precision in the prior art are solved, the extreme service environment of the special glass can be truly simulated, and a basis is provided for evaluating the thermal shock resistance of the special glass.

Description

Technical Field

[0001] This invention belongs to the field of glass performance testing technology, specifically, it relates to a method for testing the thermal shock resistance of special glass. Background Technology

[0002] Specialty glasses, due to their excellent physical and chemical properties, have been widely used in aerospace, military, chemical, optical, and precision instrument fields. These glasses often need to operate in extreme temperature environments, such as spacecraft experiencing drastic temperature changes when entering and exiting the atmosphere, or deep-sea exploration equipment operating under high pressure and low temperature conditions.

[0003] However, when subjected to rapid temperature changes, specialty glasses are prone to cracking or even shattering due to thermal stress concentration, severely impacting their safety and reliability. Therefore, accurately assessing the thermal shock resistance of specialty glasses, especially their performance under extreme high and low temperature alternation environments, has become a crucial and unavoidable issue in the research and application of such materials.

[0004] Currently, there are some conventional methods for testing the thermal shock resistance of specialty glasses both domestically and internationally. However, these methods generally suffer from limitations in testing conditions, insufficient control precision, and limited coverage of low-temperature ranges, making it difficult to realistically simulate the actual stress state of materials under extreme working conditions. Most commonly used testing standards and equipment in the industry can only reach low-temperature limits of -40℃ to -70℃, and the temperature stability in the low-temperature range is extremely poor. For ultra-low-temperature environments below -70℃, there is a lack of effective refrigeration technologies and temperature control methods. This is a significant gap compared to the extreme low-temperature scenarios that specialty glasses actually face, such as deep space and deep sea environments.

[0005] Therefore, developing a testing method that can cover extreme low temperature ranges has significant practical implications and industry value. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for testing the thermal shock resistance of special glass. This method achieves accurate evaluation of the thermal shock resistance of special glass under simulated extreme service environments by precisely controlling the temperature changes during the thermal shock resistance test.

[0007] The objective of this invention can be achieved through the following technical solutions: A method for testing the thermal shock resistance of special glass includes the following steps: S1. Sample preparation: Select the special glass to be tested as the sample, and ensure that the sample size, shape and surface quality meet the test requirements. The surface is free of visible scratches, bubbles, streaks and other defects. Then, the sample is pre-annealed to eliminate internal residual stress. Then, the sample is cleaned and dried to eliminate the influence of external factors on the test results, and the test sample is obtained. S2. Test parameter setting: Set the test parameters of the test sample according to the extreme service conditions or test standards of special glass. S3. Temperature control and sample pretreatment: Start the high-temperature furnace and low-temperature bath, and heat and cool them to the test parameters of the sample in step S2, respectively, and keep them stable; put the test sample into the high-temperature furnace and keep it at the temperature to obtain the pretreated sample. S4. Sample Transfer: The pretreated sample is transferred using a sample transfer device and completely immersed in the cooling medium that has been stabilized in the low-temperature bath; at this time, the industrial high-speed camera and data acquisition system are started simultaneously. S5. Dynamic detection and data recording during the testing process: Real-time recording of the dynamic changes of the sample in the cryogenic bath using an industrial high-speed camera; S6. Sample Testing and Performance Analysis: After completing the test according to the test parameters in step S2, take out the sample; inspect the surface morphology of the sample to check for chipping and cracking; and evaluate the sample's resistance to thermal shock by combining the sample data recorded by the industrial high-speed camera. S7. Judgment of Thermal Shock Resistance Results: The test results are comprehensively judged based on pre-set judgment criteria, which include: Qualified - After completing the test according to the preset procedure in step S2, the sample is intact and has no new cracks. Unacceptable - After the test is completed according to the preset procedure in step S2, the sample breaks or new cracks appear; Grade determination: For samples that pass the assessment, the grade of thermal shock resistance can be determined based on the maximum temperature difference they can withstand or the number of cycles that would cause them to fail.

[0008] Furthermore, in step S1, the pre-annealing temperature is 20-60°C lower than the strain point temperature of the test glass, and the annealing time is 1-3 hours.

[0009] Furthermore, the test parameters in step S2 include: high temperature setpoint T, low temperature setpoint L, heat preservation time at the high temperature and low temperature setpoints, alternation time, and number of thermal shock cycles.

[0010] Furthermore, in step S3, the cryogenic bath uses liquid nitrogen refrigeration technology, with the lowest temperature point being -150℃.

[0011] Furthermore, in step S3, the temperature control accuracy of the high-temperature furnace and the low-temperature bath is ±0.5℃.

[0012] Furthermore, in step S6, the industrial high-speed camera records the sample changes in the form of video or images.

[0013] The beneficial effects of this invention are: 1. This invention extends the test low temperature limit to -150℃ by using liquid nitrogen refrigeration technology, effectively filling the gap in the field of ultra-low temperature testing in existing technologies, and can realistically simulate extreme service environments such as deep space and deep sea. 2. This invention employs a high-precision temperature control system, ensuring the consistency and repeatability of test conditions, thereby making the test results more accurate and reliable; 3. Introducing industrial high-speed cameras can dynamically record the moment when the sample breaks and fails during the test, providing data support for subsequent failure analysis; Therefore, this invention solves the problems of limited low-temperature testing range and insufficient temperature control accuracy in existing technologies, and can realistically simulate the extreme service environment of special glass, providing a basis for evaluating the thermal shock resistance performance of special glass. Attached Figure Description

[0014] The invention will now be further described with reference to the accompanying drawings.

[0015] Figure 1 This is a flowchart of the testing method according to an embodiment of the present invention. Detailed Implementation

[0016] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0017] The following embodiments of the present invention are all in accordance with Figure 1 The process shown is tested.

[0018] Example 1 A method for testing the thermal shock resistance of special glass includes the following steps: S1. Sample preparation: Aluminosilicate glass with a sample size of 60mm×60mm×5mm was selected as the sample. The surface was free of visible scratches, bubbles, and streaks. The sample was then pre-annealed at 650-700℃ for 1 hour to eliminate residual internal stress. Finally, it was ultrasonically cleaned with anhydrous ethanol and dried to obtain the test sample. S2. Test parameter settings: Set the high temperature point T=200℃, the low temperature point L=-20℃, hold the high temperature and low temperature for 5 minutes each, the alternation time is 40 seconds, and the number of cycles is 2. S3. Temperature control and sample pretreatment: Start the high-temperature furnace and low-temperature bath, heat them to 200℃ and cool them to -20℃ respectively, and keep them stable; put the test sample into the high-temperature furnace and keep it at the temperature to obtain the pretreated sample; S4. Sample Transfer: The pretreated sample is transferred from the high-temperature furnace to the low-temperature bath (using liquid nitrogen cooling technology) within a 40-second alternating time; at this time, the industrial high-speed camera and data acquisition system are started simultaneously. S5. Dynamic detection and data recording during the testing process: The dynamic changes of the sample in the low-temperature bath are recorded in real time using an industrial high-speed camera (recording sample changes in the form of video or pictures). S6. Sample testing and performance analysis: After completing two cycles of testing according to the test parameters in step S2, take out the sample; S7. Judgment of thermal shock resistance results: The test sample showed no micro-cracks. Based on the analysis of dynamic monitoring data, it was determined to be qualified.

[0019] Example 2 A method for testing the thermal shock resistance of special glass includes the following steps: S1. Sample preparation: Aluminosilicate glass with a sample size of 60mm×60mm×5mm was selected as the sample. The surface was free of visible scratches, bubbles, and streaks. The sample was then pre-annealed at 580-650℃ for 2 hours to eliminate residual internal stress. Finally, it was ultrasonically cleaned with anhydrous ethanol and dried to obtain the test sample. S2. Test parameter settings: Set the high temperature point T=300℃, the low temperature point L=-100℃, hold the high temperature and low temperature for 10min each, the alternation time is 15s, and the number of cycles is 5. S3. Temperature control and sample pretreatment: Start the high-temperature furnace and low-temperature bath, heat them to 300℃ and cool them to -100℃ respectively, and keep them stable; put the test sample into the high-temperature furnace and keep it at the temperature to obtain the pretreated sample; S4. Sample Transfer: The pretreated sample is transferred from the high-temperature furnace to the low-temperature bath (using liquid nitrogen cooling technology) within a 15-second alternating time; at this time, the industrial high-speed camera and data acquisition system are started simultaneously. S5. Dynamic detection and data recording during the testing process: The dynamic changes of the sample in the low-temperature bath are recorded in real time using an industrial high-speed camera (recording sample changes in the form of video or pictures). S6. Sample testing and performance analysis: After completing 5 cycles of testing according to the test parameters in step S2, take out the sample; S7. Judgment of thermal shock resistance results: If the test sample shows micro-cracks, it is determined to be unqualified based on the analysis of dynamic monitoring data.

[0020] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0021] The above description is merely an example and illustration of the present invention. Any modifications or additions made by those skilled in the art to the specific embodiments described, or any substitutions made in a similar manner, should fall within the protection scope of the present invention.

Claims

1. A method for testing the thermal shock resistance of special glass, characterized in that, Includes the following steps: S1. Sample preparation: Select the special glass to be tested as the sample, and ensure that the sample size, shape and surface quality meet the test requirements. The surface is free of visible scratches, bubbles and streaks. Then, the sample is pre-annealed, cleaned and dried to obtain the test sample. S2. Test parameter setting: Set the test parameters of the test sample according to the extreme service conditions or test standards of special glass. S3. Temperature control and sample pretreatment: Start the high-temperature furnace and low-temperature bath, and heat and cool them to the test parameters of the sample in step S2, respectively; put the test sample into the high-temperature furnace and keep it at the temperature to obtain the pretreated sample; S4. Sample Transfer: Use a sample transfer device to transfer the pretreated sample and immerse it completely in the cooling medium that has been stabilized in the cryogenic bath; At this moment, the industrial high-speed camera and data acquisition system are started simultaneously; S5. Dynamic detection and data recording during the testing process: Real-time recording of the dynamic changes of the sample in the cryogenic bath using an industrial high-speed camera; S6. Sample Testing and Performance Analysis: After completing the test according to the test parameters in step S2, take out the sample; inspect the surface morphology of the sample to check for chipping and cracking; and evaluate the sample's resistance to thermal shock by combining the sample data recorded by the industrial high-speed camera. S7. Judgment of Thermal Shock Resistance Results: The test results are comprehensively judged based on pre-set judgment criteria, which include: Qualified - After completing the test according to the preset procedure in step S2, the sample is intact and has no new cracks. Unacceptable - After the test is completed according to the preset procedure in step S2, the sample breaks or new cracks appear; Grade determination: For samples that pass the assessment, the grade of thermal shock resistance can be determined based on the maximum temperature difference they can withstand or the number of cycles that would cause them to fail.

2. The method for testing the thermal shock resistance of special glass according to claim 1, characterized in that, In step S1, the pre-annealing temperature is 20-60℃ lower than the strain point temperature of the test glass, and the annealing time is 1-3h.

3. The method for testing the thermal shock resistance of special glass according to claim 1, characterized in that, The test parameters in step S2 include: high temperature setpoint T, low temperature setpoint L, holding time at the high temperature and low temperature setpoints, alternation time, and number of thermal shock cycles.

4. The method for testing the thermal shock resistance of special glass according to claim 1, characterized in that, In step S3, the cryogenic bath uses liquid nitrogen refrigeration technology, with the lowest temperature point being -150℃.

5. The method for testing the thermal shock resistance of special glass according to claim 1, characterized in that, In step S3, the temperature control accuracy of the high-temperature furnace and the low-temperature bath is ±0.5℃.

6. The method for testing the thermal shock resistance of special glass according to claim 1, characterized in that, In step S6, the industrial high-speed camera records the sample changes in the form of video or images.

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