Method for testing thermal decomposition temperature rise characteristic of explosive column of initiating explosive material

Abstract

The invention particularly relates to a thermal decomposition temperature rise characteristic testing method of an initiating explosive material grain. The method comprises the following steps: establishing a temperature difference-temperature curve of the initiating explosive materials with different masses in a loose state by adopting a DTA thermal analyzer, and screening a to-be-detected explosive quantity for representing the thermal decomposition temperature rise characteristic of an explosive column of the initiating explosive materials by taking whether the DTA thermal analyzer is damaged in a testing process as an evaluation index; pressing the initiating explosive material with reference to the initiating explosive material grain pressing parameters under the to-be-detected explosive quantity to obtain a to-be-detected grain of the initiating explosive material; the method comprises the following steps: establishing a temperature difference-temperature curve of a to-be-detected explosive column of the initiating explosive material at a heating rate of not greater than 5 DEG C / min by adopting a DTA thermal analyzer, judging whether the explosive column is violently exploded or not, obtaining an initial decomposition temperature, a decomposition peak temperature and a temperature difference peak temperature of the explosive column, and analyzing the thermal decomposition temperature rise characteristic of the explosive column of the initiating explosive material; the method has the advantages that the to-be-tested sample is close to the actual application condition, and the test result is high in accuracy.

Description

Technical Field

[0001] The invention relates to the field of pyrotechnic agents and thermal analysis testing, and in particular to a method for testing the thermal decomposition temperature rise characteristics of pyrotechnic agent columns. Background Art

[0002] Compared with pyrotechnic powder, pyrotechnic powder columns have shown significant advantages in energy release control, safety, ease of operation, and compatibility with pyrotechnic devices. It is precisely because of these advantages that the column form has gained widespread attention in many pyrotechnic application scenarios. Studying the thermal decomposition temperature rise characteristics of pyrotechnic powder columns is irreplaceable and necessary to ensure safety during use, ensure the reliability of pyrotechnic performance, meet the specific needs of different application scenarios, and even promote the development of pyrotechnics and related industries. Its importance is self-evident.

[0003] At present, the research on the thermal decomposition temperature rise characteristics of pyrotechnic agents mainly focuses on powder materials in a loose state, and there is a lack of research directly on the thermal decomposition temperature rise characteristics of pyrotechnic agent columns. When the pyrotechnic agent powder is in a loose state, the distance between its particles is relatively large, and the interaction between them and the energy transfer method are significantly different from the situation after being pressed into a column. When the pyrotechnic agent receives external heat input and undergoes a thermal decomposition reaction, the internal agent particles are tightly compacted, and the more orderly arranged column will show temperature rise characteristics that are different from the loose powder state. Therefore, it is difficult to accurately provide a reliable and precise reference for the temperature rise characteristics of pyrotechnic agent columns based solely on the research results of the thermal decomposition temperature rise characteristics of pyrotechnic agents in a loose powder state, thereby providing a more solid theoretical basis and technical support for the rational use and safety of pyrotechnic agent columns in various application scenarios. Summary of the invention

[0004] The present invention solves the technical problem that there is currently a lack of direct research on the thermal decomposition temperature rise characteristics of pyrotechnic agent powder columns, and provides a method for testing the thermal decomposition temperature rise characteristics of pyrotechnic agent powder columns. The present invention is based on a differential thermal analyzer (hereinafter referred to as a DTA thermal analyzer) and is a testing method for measuring the thermal decomposition temperature rise characteristics of pyrotechnic agent powder columns. The method of the present invention has the advantages that the sample to be tested is close to the actual application situation and the test result is highly accurate.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for testing the thermal decomposition temperature rise characteristics of an explosive charge, comprising the following steps: (1) Screening of the amount of explosives to be tested for thermal decomposition Based on the differential thermal analysis (hereinafter referred to as DTA) test method, a DTA thermal analyzer is used to establish the temperature difference-temperature curve of different masses of pyrotechnic agents in the loose state. According to the temperature difference-temperature curve in the loose state, it is judged whether the pyrotechnic agents of different masses will damage the DTA thermal analyzer. Whether the test process will damage the DTA thermal analyzer and thus affect the normal progress of subsequent tests is used as an evaluation index to screen out the test amount for characterizing the temperature rise characteristics of the thermal decomposition of the pyrotechnic agent column; (2) Suppress the explosive charge to be tested The pyrotechnic agent is compressed according to the pyrotechnic agent column compression parameters under actual conditions, and the amount of the pyrotechnic agent is the amount of the pyrotechnic agent to be tested selected in step (1), thereby obtaining the pyrotechnic agent column to be tested; (3) Test the thermal decomposition temperature rise characteristics of the pyrotechnic agent column A DTA thermal analyzer is used to establish a temperature difference-temperature curve of the explosive charge to be tested at a heating rate of no more than 5 °C / min, to determine whether the charge has a violent explosion, to obtain the initial decomposition temperature and decomposition peak temperature of the charge without a violent explosion, and to obtain the initial decomposition temperature and temperature difference peak temperature of the charge with a violent explosion; (4) Analysis of the thermal decomposition temperature rise characteristics of the pyrotechnic agent column For the explosive columns pressed under actual pressure parameters, the initial decomposition temperature, decomposition peak temperature and temperature difference peak temperature are used to characterize the thermal decomposition temperature rise characteristics of the pyrotechnic propellant columns. For a series of explosive columns formed under unrealistic pressure parameters, the changing patterns of the initial decomposition temperature, decomposition peak temperature and temperature difference peak temperature of different explosive columns are explored, and the thermal decomposition temperature rise characteristics of the pyrotechnic propellant columns are inferred.

[0006] The method for testing the thermal decomposition temperature rise characteristics of the pyrotechnic agent column of the present invention is carried out under specific working conditions, and the specific working conditions are working conditions existing in actual application scenarios. For example, in the fields of aerospace, military ammunition, and industrial blasting, the pyrotechnic agent will be pressed into columns of different structures under different pressing parameters for different application scenarios and different charging structure requirements.

[0007] As a further limitation of the technical solution of the present invention, the amount of charge to be tested in step (1) is divided into two categories: 1) if the loose pyrotechnic charge with a mass equal to the actual mass of the pyrotechnic charge column does not damage the DTA thermal analyzer during the test, the amount of charge to be tested is the actual amount of charge of the pyrotechnic charge column; 2) if the loose pyrotechnic charge with a mass equal to the actual mass of the pyrotechnic charge column damages the DTA thermal analyzer during the test, the amount of charge to be tested is a series of amounts that will not damage the DTA thermal analyzer during the test and are less than the actual amount of charge of the pyrotechnic charge column, wherein at least one amount in the series is infinitely close to the actual mass of the pyrotechnic charge column, and the series of amounts is not less than 3.

[0008] As a further limitation of the technical solution of the present invention, the test powder columns in step (2) are divided into two categories: 1) if the pyrotechnic agent with the test amount can be pressed and formed under the actual pressure parameters, and the size meets the DTA thermal analyzer sample testing requirements, the test powder columns at this time are powder columns pressed and formed under the actual pressure parameters; 2) if the pyrotechnic agent with the test amount cannot be pressed and formed under the actual pressure parameters, or the size of the pressed powder columns does not meet the DTA thermal analyzer sample testing requirements, the test powder columns at this time are a series of powder columns pressed and formed under unrealistic pressure parameters, and at least one of the test powder columns in the series has a pressure parameter that is infinitely close to the actual pressure parameter of the pyrotechnic agent column, and the series of powder columns has no less than 3 types.

[0009] As a further limitation of the technical solution of the present invention, the evaluation criteria for whether the explosive column in step (3) has undergone a violent explosion are: 1) if a clear explosion sound is emitted during the thermal decomposition of the explosive column or the glass container containing the explosive column is ruptured during the test, it is considered that the explosive column has undergone a violent explosion; 2) if no clear explosion sound is emitted during the thermal decomposition of the explosive column and the glass container containing the explosive column is not ruptured during the test, it is considered that the explosive column has not undergone a violent explosion.

[0010] As a further limitation of the technical solution of the present invention, the initial decomposition temperature in step (3) is the temperature corresponding to the intersection of the tangent line at the maximum slope of the temperature difference-temperature curve in the rising stage and the baseline before the peak appears.

[0011] As a further limitation of the technical solution of the present invention, the decomposition peak temperature in step (3) is the temperature corresponding to the extreme value of the curve within the temperature range where the corresponding peak appears in the temperature difference-temperature curve of the explosive column without violent explosion.

[0012] As a further limitation of the technical solution of the present invention, the temperature difference peak temperature in step (3) is the temperature corresponding to the extreme value of the curve within the temperature range where the last peak appears before the explosion in the temperature difference-temperature curve of the explosive column undergoing violent explosion.

[0013] Compared with the prior art, the present invention has the following beneficial effects: (1) Compared with other DTA test methods, the method of the present invention increases the amount of test sample and improves the instrument response.

[0014] (2) The method of the present invention avoids misjudgment of the temperature rise characteristics of the thermal decomposition of the pyrotechnic agent column due to the amount of the test sample used.

[0015] (3) The method of the present invention avoids the misjudgment of the temperature rise characteristics of the thermal decomposition of the explosive charge due to the fact that the test samples in the non-charge state are not stacked tightly enough and the energy released by the explosive charge reaction cannot be smoothly transmitted.

[0016] (4) The method of the present invention is particularly suitable for testing the thermal decomposition temperature rise characteristics of pyrotechnic agents during actual production and operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is the temperature difference-temperature curve of the drug column sample established in Example 1 of the present invention.

[0018] Figure 2 This is the temperature difference-temperature curve of the drug column sample established in Example 2 of the present invention.

[0019] Figure 3 This is the temperature difference-temperature curve of the drug column sample established in Example 3 of the present invention. DETAILED DESCRIPTION

[0020] The present invention is further described below in conjunction with specific embodiments. Example 1

[0021] A method for testing the thermal decomposition temperature rise characteristics of an explosive charge under specific working conditions comprises the following steps: (1) First, the temperature difference-temperature curve of different masses of RDX (hereinafter referred to as RDX) in loose state was established using a DTA thermal analyzer. The mass of the RDX column under specific working conditions was 50 mg. The DTA thermal analyzer was not damaged during the test of the thermal decomposition temperature rise characteristics when the RDX loose test amount was gradually increased from 10 mg to 50 mg. Therefore, 50 mg was selected as the test amount of the RDX column thermal decomposition temperature rise characteristics.

[0022] (2) Under this specific working condition, 50 mg of RDX needs to be pressed into a 3.5 mm diameter column. After pressing 50 mg of RDX under the RDX column pressing parameters under this specific working condition, an RDX column with a diameter of 3.5 mm with good molding effect can be obtained. The size of this column meets the sample testing requirements of the DTA thermal analyzer. Therefore, this size of column is determined as the RDX column to be tested in the subsequent thermal decomposition temperature rise characteristic test.

[0023] (3) Use DTA thermal analyzer to establish the temperature difference-temperature curve of the RDX column under the heating rate of 5 ℃ / min. The curve is as follows: Figure 1 During the test, the RDX powder column did not make a clear explosion sound and did not break the glass test tube containing the powder column, and no violent explosion occurred.

[0024] (4) By Figure 1It can be seen that the RDX column will have an endothermic peak and an exothermic peak when the temperature is higher than 200 °C. The endothermic peak is the melting endothermic peak of RDX, and the exothermic peak is the decomposition exothermic peak of RDX. RDX decomposes and exotherms soon after it starts to melt. The initial decomposition temperature of the RDX column is 209.92 °C, and the decomposition peak temperature is 219.66 °C. Example 2

[0025] A method for testing the thermal decomposition temperature rise characteristics of an explosive charge under specific working conditions comprises the following steps: (1) First, the temperature difference-temperature curve of different masses of Octogen (hereinafter referred to as HMX) in loose state was established using a DTA thermal analyzer. The mass of the HMX column under specific working conditions was 50 mg. The DTA thermal analyzer was not damaged during the thermal decomposition temperature rise characteristic test process when the HMX loose test amount was gradually increased from 10 mg to 50 mg. Therefore, 50 mg was selected as the test amount of the HMX column thermal decomposition temperature rise characteristic.

[0026] (2) Under this specific working condition, 50 mg HMX needs to be pressed into a 4.0 mm diameter column. The 4.0 mm HMX column cannot meet the sample testing requirements of the DTA thermal analyzer, so we try to press columns with diameters of 2.5, 3.0, and 3.5 mm as the test columns. After pressing 50 mg HMX under the HMX column pressing parameters under this specific working condition, HMX columns with diameters of 2.5, 3.0, and 3.5 mm can be obtained with good molding effects. This series of column sizes can meet the sample testing requirements of the DTA thermal analyzer, so this series of columns is determined as the HMX column to be tested in the subsequent thermal decomposition temperature rise characteristic test.

[0027] (3) Use DTA thermal analyzer to establish the temperature difference-temperature curve of the HMX column under test at a heating rate of 5 ℃ / min. The curve is as follows: Figure 2 During the test, the HMX powder column did not make a clear explosion sound and did not break the glass test tube containing the powder column, and no violent explosion occurred.

[0028] (4) By Figure 2It can be seen that the HMX grain will have a decomposition exothermic peak when the temperature is higher than 250 ℃. The initial decomposition temperatures of 2.5, 3.0 and 3.5 mm HMX grains are 275.81, 275.68 and 275.66 ℃, respectively, and the decomposition peak temperatures are 277.15, 276.90 and 276.58 ℃, respectively. The change in the diameter of the HMX grain did not cause significant changes in its thermal decomposition process, initial decomposition temperature and decomposition peak temperature. Therefore, it is speculated that the thermal decomposition temperature rise characteristics of the 4.0 mm diameter HMX grain are similar to those of the 2.5, 3.0 and 3.5 mm HMX grains. Example 3

[0029] A method for testing the thermal decomposition temperature rise characteristics of an explosive charge under specific working conditions comprises the following steps: (1) First, a DTA thermal analyzer was used to establish the temperature difference-temperature curve of different masses of lead styphnate (hereinafter referred to as LTNR) in the loose state. The mass of the LTNR column under specific working conditions is 30 mg. During the test of the thermal decomposition temperature rise characteristics of the LTNR loose test charge gradually increased from 2 mg to 18.8 mg, it was found that the loose LTNR would emit a clear explosion sound and cause the glass test tube containing the charge to break and explode violently. When the LTNR test charge was 18.8 mg, the temperature sensor was severely deformed. In order to ensure that the subsequent tests can proceed normally and smoothly, 12.5, 15.0 and 18.8 mg were selected as the test charges for the thermal decomposition temperature rise characteristics of the LTNR column.

[0030] (2) Under this specific working condition, LTNR needs to be pressed into a 2.6 mm diameter column. After pressing 12.5, 15.0 and 18.8 mg LTNR under the LTNR column pressing parameters under this specific working condition, LTNR columns with a diameter of 2.6 mm with good molding effect can be obtained. This column size meets the sample testing requirements of the DTA thermal analyzer, so a series of columns of this size are determined as the LTNR columns to be tested in the subsequent thermal decomposition temperature rise characteristics test.

[0031] (3) The temperature difference-temperature curve of the LTNR column to be tested at a heating rate of 5 °C / min was established using a DTA thermal analyzer. Figure 3 During the test, the LTNR will emit a clear explosion sound and the glass test tube containing the powder column will break, causing a violent explosion.

[0032] (4) By Figure 3It can be seen that the LTNR pellet will have an endothermic peak and an exothermic peak when the temperature is higher than 100 ℃. The endothermic peak is the melting endothermic peak of LTNR, and the exothermic peak is the decomposition exothermic peak of LTNR. The LTNR pellet exploded at the moment when the exothermic peak reached its peak value, and the temperature difference-temperature curve thereafter could no longer reflect the thermal decomposition temperature rise characteristics of the LTNR pellet. The initial decomposition temperatures of 12.5, 15.0 and 18.8 mg LTNR pellets were 266.49, 264.90 and 265.26 ℃, respectively, and the temperature difference peak temperatures were 267.95, 266.44 and 266.37 ℃, respectively. The change in the dosage of the LTNR pellet did not cause significant changes in its thermal decomposition process, initial decomposition temperature and temperature difference peak temperature. Therefore, it is inferred that the thermal decomposition temperature rise characteristics of the LTNR pellet with a dosage of 30 mg are similar to those of 12.5, 15.0 and 18.8 mg LTNR pellets.

[0033] The specific working conditions in the above embodiments are working conditions existing in actual application scenarios, such as aerospace, military ammunition, and industrial blasting. For different application scenarios and different charging structure requirements, the pyrotechnic agent will be pressed into powder columns with different structures under different pressing parameters. The present invention aims to test the temperature rise characteristics of pyrotechnic agent powder columns under all working conditions. The principle of the test is: when the actual application situation (including the actual amount of powder and the structure of the powder column) can be fully simulated, the test is directly carried out; when the actual application situation cannot be fully simulated, the actual situation is approached as much as possible, and the temperature rise characteristics in actual applications are predicted by testing the data of powder columns of different masses and structures.

Claims

1. A method for testing the thermal decomposition temperature rise characteristics of an explosive charge, characterized in that: The following steps are involved: (1) Screening the amount of explosives to be tested for thermal decomposition Based on the DTA test method, a DTA thermal analyzer was used to establish the temperature difference-temperature curve of different masses of pyrotechnic agents in the loose state. The temperature difference-temperature curve in the loose state was used to determine whether the pyrotechnic agents of different masses would damage the DTA thermal analyzer. Whether the test process would damage the DTA thermal analyzer was used as an evaluation index to screen out the amount of pyrotechnic agents to be tested for characterizing the temperature rise characteristics of the thermal decomposition of the pyrotechnic agent column. (2) Suppress the explosive charge to be tested The pyrotechnic agent is compressed according to the pyrotechnic agent column compression parameters under actual conditions, and the amount of the pyrotechnic agent is the amount of the pyrotechnic agent to be tested selected in step (1), thereby obtaining the pyrotechnic agent column to be tested; (3) Test the thermal decomposition temperature rise characteristics of the pyrotechnic agent column A DTA thermal analyzer is used to establish a temperature difference-temperature curve of the explosive charge to be tested at a heating rate of no more than 5 °C / min, to determine whether the charge has a violent explosion, to obtain the initial decomposition temperature and decomposition peak temperature of the charge without a violent explosion, and to obtain the initial decomposition temperature and temperature difference peak temperature of the charge with a violent explosion; (4) Analysis of the thermal decomposition temperature rise characteristics of the pyrotechnic agent column For the explosive columns pressed under actual pressure parameters, the initial decomposition temperature, decomposition peak temperature and temperature difference peak temperature are used to characterize the thermal decomposition temperature rise characteristics of the pyrotechnic propellant columns. For a series of explosive columns formed under unrealistic pressure parameters, the changing patterns of the initial decomposition temperature, decomposition peak temperature and temperature difference peak temperature of different explosive columns are explored, and the thermal decomposition temperature rise characteristics of the pyrotechnic propellant columns are inferred.

2. A method for testing the thermal decomposition temperature rise characteristics of an ignition charge according to claim 1, characterized in that: The amount of explosive to be tested in step (1) is divided into two categories: 1) if the loose explosive with a mass equal to the actual mass of the explosive column does not damage the DTA thermal analyzer during the test, the amount of explosive to be tested is the actual amount of explosive column; 2) if the loose explosive with a mass equal to the actual mass of the explosive column damages the DTA thermal analyzer during the test, the amount of explosive to be tested is a series of amounts that will not damage the DTA thermal analyzer during the test and are less than the actual mass of the explosive column, wherein at least one amount in the series is infinitely close to the actual mass of the explosive column, and the series of amounts is not less than 3.

3. The method for testing the thermal decomposition temperature rise characteristics of an explosive charge according to claim 1, characterized in that: The explosive columns to be tested in step (2) are divided into two categories: 1) If the pyrotechnic agent with the amount to be tested can be pressed and formed under the actual pressure parameters, and the size meets the DTA thermal analyzer sample testing requirements, the explosive columns to be tested at this time are explosive columns pressed and formed under the actual pressure parameters; 2) If the pyrotechnic agent with the amount to be tested cannot be pressed and formed under the actual pressure parameters, or the size of the pressed and formed explosive columns does not meet the DTA thermal analyzer sample testing requirements, the explosive columns to be tested at this time are a series of explosive columns pressed and formed under unrealistic pressure parameters, and at least one of the explosive columns in the series has a pressure parameter that is infinitely close to the actual pressure parameter of the pyrotechnic agent column, and the series of explosive columns is not less than 3 types.

4. The method for testing the thermal decomposition temperature rise characteristics of an explosive charge according to claim 1, characterized in that: The evaluation criteria for whether the explosive column in step (3) has undergone a violent explosion are: 1) If a clear explosion sound is emitted during the thermal decomposition of the explosive column or the glass container containing the explosive column is ruptured during the test, it is considered that the explosive column has undergone a violent explosion; 2) If no clear explosion sound is emitted during the thermal decomposition of the explosive column and the glass container containing the explosive column is not ruptured during the test, it is considered that the explosive column has not undergone a violent explosion.

5. The method for testing the thermal decomposition temperature rise characteristics of an explosive charge according to claim 1, characterized in that: The initial decomposition temperature in step (3) is the temperature corresponding to the intersection of the tangent line at the maximum slope in the rising phase of the temperature difference-temperature curve and the baseline before the peak appears.

6. A method for testing the thermal decomposition temperature rise characteristics of an ignition charge according to claim 1, characterized in that: The decomposition peak temperature in step (3) is the temperature corresponding to the extreme value of the temperature difference-temperature curve of the explosive column without violent explosion, within the temperature range where the corresponding peak appears.

7. A method for testing the thermal decomposition temperature rise characteristics of an explosive charge according to claim 1, characterized in that: The temperature difference peak temperature in step (3) is the temperature corresponding to the extreme value of the temperature difference-temperature curve of the explosive column that undergoes violent explosion, within the temperature range where the last peak appears before the explosion.

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