A method and system for safety detection of long-tube trailer gas cylinders after fire

Abstract

The present invention relates to a method and system for detecting the safety of a gas cylinder in a long-tube trailer after a fire. First, a metallographic inspection is performed on the gas cylinder in the long-tube trailer after the fire to determine whether the metallographic structures of the fire-affected part and the non-fire-affected part of the gas cylinder are consistent. If they are consistent, a magnetic multi-parameter detection is performed on the fire-affected part, and the mechanical property state value corresponding to the fire-affected part is obtained based on a multivariate linear regression equation, and then the mechanical property state value is compared with a preset threshold value to determine whether the gas cylinder is in a safe state. If they are inconsistent, the mechanical properties of the fire-affected part are determined according to the metallographic structure of the fire-affected part, and then the mechanical properties are compared with the standard mechanical properties to determine whether the gas cylinder is in a safe state. The detection method provided by the present invention can determine the safety state of the gas cylinder regardless of whether the fire-affected part of the gas cylinder undergoes a phase change, and can perform safety detection on the gas cylinder more comprehensively and effectively, thereby improving the reliability of the detection results.

Description

Technical Field

[0001] The invention relates to the technical field of gas cylinder safety detection, and in particular to a method and system for detecting gas cylinder safety in a long-tube trailer after a fire. Background Art

[0002] As a mobile pressure vessel, the long tube trailer is mainly used to contain compressed natural gas in China, providing storage and transportation guarantee for natural gas in areas where pipeline laying is inconvenient and in cities. There are more than 14,000 units in the domestic market. The long tube trailer is mainly assembled by connecting several large-capacity seamless steel cylinders through pipelines. The design working pressure is generally 20MPa, and the volume is about 18-30m 3 It is mainly used to contain high-pressure flammable and explosive gases. Once an accident occurs, it will cause immeasurable losses to people’s property and safety. Therefore, the safety inspection of long-tube trailers during use becomes particularly important.

[0003] According to statistics, there are several long-tube trailer fire accidents every year. When evaluating the safety of long-tube trailer gas cylinders after a fire accident, the commonly used inspection and testing method is to conduct on-site metallographic tests to compare whether the metallographic structure of the fire-affected area and the non-fire-affected area has changed, so as to judge the safety of the long-tube trailer gas cylinder after the fire accident. However, this inspection method is not rigorous. The change of metallographic structure does correspond to the change of mechanical properties of the material, but it is not clear whether the change of mechanical properties exceeds the acceptable standard range. Moreover, the phase transition temperature of the material structure of the long-tube trailer gas cylinder is about 740℃, and the fire temperature of the gas cylinder in the fire environment is difficult to judge. Therefore, when the fire temperature of the gas cylinder wall does not reach the phase transition temperature, the metallographic structure of the gas cylinder material may not change significantly, but it is not clear whether the mechanical properties at this time do not meet the standard requirements. Therefore, it is necessary to study an effective testing and evaluation method for determining the safety status of the long-tube trailer gas cylinder exposed to fire after a fire accident. Summary of the invention

[0004] The purpose of the present invention is to provide a method and system for detecting the safety of a gas cylinder in a long tube trailer after a fire, which can effectively detect the safety of the gas cylinder in the long tube trailer after a fire and improve the reliability of the detection result.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] A method for detecting the safety of a gas cylinder in a long-tube trailer after a fire, the method comprising:

[0007] Performing metallographic inspection on the gas cylinder of the long tube trailer after the fire to determine whether the metallographic structures of the fire-affected part and the non-fire-affected part of the gas cylinder are consistent, thereby obtaining a first determination result;

[0008] If the first judgment result is yes, a magnetic multi-parameter detection is performed on the fire-affected part to obtain a magnetic multi-parameter characteristic signal; and the magnetic multi-parameter characteristic signal is used as input to obtain a mechanical property state value corresponding to the fire-affected part using a multivariate linear regression equation; the mechanical property state value is compared with a preset threshold value to determine whether the gas cylinder is in a safe state; the magnetic multi-parameter detection includes magnetic Barkhausen noise detection, multi-frequency eddy current detection, incremental magnetic permeability detection and tangential magnetic field harmonic detection; the multivariate linear regression equation is used to characterize the correlation between the magnetic multi-parameter characteristic signal and the mechanical property state value;

[0009] If the first judgment result is no, the mechanical properties of the fire-affected part are determined according to the metallographic structure of the fire-affected part and the correspondence between the pre-established metallographic map and the mechanical properties; the mechanical properties are compared with the standard mechanical properties to determine whether the gas cylinder is in a safe state.

[0010] A post-fire long-tube trailer gas cylinder safety detection system, the detection system comprising:

[0011] A metallographic structure comparison module is used to perform a metallographic inspection on the gas cylinder of the long tube trailer after the fire, determine whether the metallographic structures of the fire-affected part and the non-fire-affected part of the gas cylinder are consistent, and obtain a first determination result;

[0012] A magnetic multi-parameter determination module, for, if the first judgment result is yes, performing magnetic multi-parameter detection on the fire-affected part to obtain a magnetic multi-parameter characteristic signal; and using the magnetic multi-parameter characteristic signal as input, obtaining a mechanical property state value corresponding to the fire-affected part by using a multivariate linear regression equation; comparing the mechanical property state value with a preset threshold value to determine whether the gas cylinder is in a safe state; the magnetic multi-parameter detection includes magnetic Barkhausen noise detection, multi-frequency eddy current detection, incremental magnetic permeability detection and tangential magnetic field harmonic detection; the multivariate linear regression equation is used to characterize the correlation between the magnetic multi-parameter characteristic signal and the mechanical property state value;

[0013] The metallographic spectrum determination module is used to determine the mechanical properties of the fire-affected part according to the metallographic structure of the fire-affected part and the correspondence between the pre-established metallographic spectrum and the mechanical properties if the first judgment result is no; and compare the mechanical properties with the standard mechanical properties to determine whether the gas cylinder is in a safe state.

[0014] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0015] The present invention is used to provide a method and system for detecting the safety of a gas cylinder in a long-tube trailer after a fire. First, a metallographic inspection is performed on the gas cylinder in the long-tube trailer after the fire to determine whether the metallographic structures of the fire-affected part and the non-fire-affected part of the gas cylinder are consistent. If they are consistent, a magnetic multi-parameter detection is performed on the fire-affected part to obtain a magnetic multi-parameter characteristic signal, and the magnetic multi-parameter characteristic signal is used as an input to obtain a mechanical property state value corresponding to the fire-affected part using a multivariate linear regression equation, and then the mechanical property state value is compared with a preset threshold value to determine whether the gas cylinder is in a safe state. If they are inconsistent, the mechanical properties of the fire-affected part are determined according to the metallographic structure of the fire-affected part and the correspondence between the pre-established metallographic spectrum and the mechanical properties, and then the mechanical properties are compared with the standard mechanical properties to determine whether the gas cylinder is in a safe state. The detection method provided by the present invention can determine the safety state of the gas cylinder regardless of whether the fire-affected part of the gas cylinder undergoes a phase change, and can perform safety detection on the gas cylinder more comprehensively and effectively, thereby improving the reliability of the detection results. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] 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.

[0017] Figure 1 A flow chart of the detection method provided in Example 1 of the present invention;

[0018] Figure 2 A detection principle diagram of the magnetic multi-parameter detection method provided in Example 1 of the present invention;

[0019] Figure 3 The metallographic spectrum of the damaged test block in the original state provided by Example 1 of the present invention;

[0020] Figure 4 The metallographic spectrum of the damaged test block obtained by heat preservation at 650° C. for 2 hours and air cooling provided in Example 1 of the present invention;

[0021] Figure 5 The metallographic spectrum of the damaged test block obtained by air cooling at 700°C for 2 hours provided in Example 1 of the present invention;

[0022] Figure 6 The metallographic spectrum of the damaged test block obtained by heat preservation at 730° C. for 2 hours and air cooling provided in Example 1 of the present invention;

[0023] Figure 7 The metallographic spectrum of the damaged test block obtained by heat preservation at 750° C. for 2 hours and air cooling provided in Example 1 of the present invention;

[0024] Figure 8 The metallographic spectrum of the damaged test block obtained by keeping at 770° C. for 2 hours and air cooling provided in Example 1 of the present invention;

[0025] Fig. 9 The metallographic spectrum of the damaged test block obtained by heat preservation at 800° C. for 2 hours and air cooling provided in Example 1 of the present invention;

[0026] Fig.10 The metallographic spectrum of the damaged test block obtained by heat preservation at 850° C. for 2 hours and air cooling provided in Example 1 of the present invention;

[0027] Fig.11 A schematic diagram of the yield strength of damaged test blocks at different fire temperatures provided in Example 1 of the present invention;

[0028] Fig.12 A schematic diagram of the tensile strength of damaged test blocks at different fire temperatures provided in Example 1 of the present invention;

[0029] Fig.13 A schematic diagram of the impact work of damaged test blocks at different fire temperatures provided in Example 1 of the present invention;

[0030] Fig.14 A schematic diagram of the hardness of damaged test blocks at different fire temperatures provided in Example 1 of the present invention;

[0031] Fig.15 This is a system block diagram of the detection system provided in Example 2 of the present invention. DETAILED DESCRIPTION

[0032] 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.

[0033] The purpose of the present invention is to provide a method and system for detecting the safety of a gas cylinder in a long tube trailer after a fire, which can effectively detect the safety of the gas cylinder in the long tube trailer after a fire and improve the reliability of the detection result.

[0034] 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.

[0035] Embodiment 1:

[0036] This embodiment is used to provide a method for safety detection of gas cylinders in a long-tube trailer after a fire. Figure 1 As shown, the detection method comprises:

[0037] S1: Performing metallographic inspection on the gas cylinder of the long tube trailer after the fire to determine whether the metallographic structures of the fire-affected part and the non-fire-affected part of the gas cylinder are consistent, and obtaining a first determination result;

[0038] A post-fire long-tube trailer is a long-tube trailer that has experienced a fire. In the process of inspecting and evaluating the long-tube trailer gas cylinder after a fire, a metallographic inspection is first performed to observe whether the metallographic structures of the fire-affected and non-fire-affected parts of the gas cylinder are consistent. Since the phase transition temperature of the material structure of the long-tube trailer gas cylinder is about 740°C, the metallographic structure of the gas cylinder will only change significantly when the fire temperature of the gas cylinder wall reaches the phase transition temperature. Therefore, this embodiment first compares the metallographic structures of the fire-affected and non-fire-affected parts to determine whether the fire-affected parts of the gas cylinder undergo a phase change. If a phase change occurs, that is, the metallographic structures are inconsistent, then the comparison of the metallographic structures is used to determine whether the gas cylinder is in a safe state; if no phase change occurs, that is, the metallographic structure has no obvious change, then the magnetic multi-parameter detection method is used to determine whether the gas cylinder is in a safe state, and then the safety of the gas cylinder can be detected regardless of whether a phase change occurs, and the safety of the gas cylinder can be detected more comprehensively, thereby improving the reliability of the detection results.

[0039] S2: If the first judgment result is yes, then perform magnetic multi-parameter detection on the fire-affected part to obtain a magnetic multi-parameter characteristic signal; and use the magnetic multi-parameter characteristic signal as input to obtain the mechanical property state value corresponding to the fire-affected part using a multivariate linear regression equation; compare the mechanical property state value with a preset threshold to determine whether the gas cylinder is in a safe state; the magnetic multi-parameter detection includes magnetic Barkhausen noise detection, multi-frequency eddy current detection, incremental magnetic permeability detection and tangential magnetic field harmonic detection; the multivariate linear regression equation is used to characterize the correlation between the magnetic multi-parameter characteristic signal and the mechanical property state value;

[0040] Magnetic multi-parameter detection technology can be used to evaluate the microstructure changes, stress state and micro-damage defects of ferromagnetic materials. Figure 2 As shown, the magnetic multi-parameter detection method used in this embodiment needs to combine magnetic Barkhausen noise, multi-frequency eddy current, incremental magnetic permeability and tangential magnetic field harmonic analysis technologies to perform multi-parameter fusion detection and analysis.

[0041] In S2, the magnetic multi-parameter detection is performed on the fire-affected part, and the magnetic multi-parameter characteristic signal obtained may include:

[0042] (1) The magnetic multi-parameter detection is performed on the fire-affected part by a magnetic multi-parameter detector to obtain a multi-parameter detection electromagnetic signal; the multi-parameter detection electromagnetic signal includes a magnetic Barkhausen noise signal, a multi-frequency eddy current signal, an incremental permeability signal, and a magnetic field harmonic signal. The intensity and change of the multi-parameter detection electromagnetic signal are usually described by parameters such as amplitude, energy, root mean square, waveform half-height width, envelope, peak time, and power spectrum.

[0043] (2) filtering, separating and transforming the multi-parameter detection electromagnetic signal to obtain a processed signal;

[0044] (3) extracting features from the processed signal to obtain a magnetic multi-parameter feature signal; the magnetic multi-parameter feature signal includes the amplitude and envelope characteristics of the magnetic Barkhausen noise signal, the impedance amplitude and phase of the multi-frequency eddy current signal, the curve width and amplitude of the incremental permeability signal, and the harmonic amplitude and phase of the magnetic field harmonic signal.

[0045] Material damage will affect its magnetic detection signals, such as magnetic Barkhausen signals, incremental magnetic permeability signals, multi-frequency eddy currents, coercive force and residual magnetic intensity, etc., but the relationship between material temperature damage and magnetic detection signals is uncertain. Therefore, in order to analyze the correlation between the material's magnetic multi-parameter characteristic signal and material temperature damage, this embodiment introduces a regression analysis method for fusion detection. In linear regression, data is modeled using a linear prediction function, and unknown model parameters are also estimated through data. This embodiment uses a multivariate linear regression equation to characterize the correlation between the magnetic multi-parameter characteristic signal and the mechanical property state value. The multivariate linear regression equation is a regression analysis model that models the correlation between multiple independent variables and dependent variables, and its mathematical model is as follows:

[0046] y=β0+β1x1+β2x2+…+β p x p +ε; (1)

[0047] In formula (1), y is the dependent variable, x1,…,x p are independent variables, β0,…,β p is the regression parameter and ε is the error term.

[0048] This embodiment defines the material temperature damage state value (i.e., the mechanical property state value) as the dependent variable and the magnetic multi-parameter characteristic signal as the independent variable, uses multivariate linear regression to analyze the correlation between the material damage state and the magnetic detection signal, and establishes a multivariate linear regression equation for quantitative analysis.

[0049] The steps to establish a multiple linear regression equation may include:

[0050] (1) Prepare damage test pieces of gas cylinders at different fire temperatures;

[0051] Specifically, the gas cylinder is cut to obtain multiple samples; the samples are heat treated, each sample corresponds to a heat treatment state, and damaged test blocks under multiple heat treatment states are obtained. The damaged test blocks under different heat treatment states are damaged test blocks under different fire temperatures. More specifically, a heat treatment simulation is performed on the long-tube trailer gas cylinder. The experimental sample is taken from the long-tube trailer gas cylinder, and the gas cylinder is cut into multiple 170mm×85mm samples. It should be noted that the size and shape of the sample are arbitrary, and the 170mm×85mm sample given here is only an example. According to research, the external temperature of the gas cylinder can reach up to 800℃. Therefore, when the heat treatment simulation is performed in this embodiment, the maximum heating temperature is set to 850℃, and 650℃, 700℃, 730℃, 750℃, 770℃, 800℃, and 850℃ are selected as the set temperatures. A high-temperature box-type resistance furnace was used for heat treatment. The sample was placed in the resistance furnace at room temperature, heated, and kept warm after being heated to the set temperature for 2 hours. After being taken out, it was cooled to room temperature by air cooling to obtain the damaged test block under the heat treatment state. Each sample corresponds to a set temperature, and damaged test blocks under multiple heat treatment states are obtained.

[0052] (2) Conducting mechanical property tests on the damaged test blocks and the original test blocks under various heat treatment conditions, and obtaining the mechanical property state value and safety state corresponding to each damaged test block by comparing the standard mechanical property calibration state value;

[0053] In order to facilitate measurement and analysis, the state values ​​of the damaged test blocks under the above-mentioned different fire temperatures were calibrated. The calibration results are shown in Table 1 below.

[0054] Table 1

[0055]

[0056]

[0057] It should be noted that the original state referred to in Table 1 means that the sample is not heated, that is, the sample is in the original state of the long tube trailer gas cylinder material.

[0058] (3) Performing magnetic multi-parameter detection on the damaged test block to obtain a magnetic multi-parameter characteristic signal corresponding to each damaged test block;

[0059] (4) Taking the magnetic multi-parameter characteristic signal as the independent variable and the mechanical property state value as the dependent variable, an initial multiple linear regression equation is established; the initial multiple linear regression equation is as shown in formula (1).

[0060] (5) The mechanical property state value and magnetic multi-parameter characteristic signal corresponding to each damaged specimen are used as input to determine the model parameters of the initial multivariate linear regression equation and obtain the multivariate linear regression equation.

[0061] This embodiment uses a multivariate linear regression method to obtain a calibration curve between magnetic multi-parameter characteristic signals and mechanical property state values, and establishes a corresponding relationship model between magnetic multi-parameter characteristic signals and mechanical property state values ​​under different fire temperature states to evaluate material mechanical property damage.

[0062] After establishing the above-mentioned multivariate linear regression equation, this embodiment obtains the magnetic multi-parameter characteristic signal of the fire-affected part and inputs it into the multivariate linear regression equation to determine the mechanical property state value of the fire-affected part. Then, the mechanical property state value is compared with the preset threshold to determine whether the gas cylinder is in a safe state.

[0063] Specifically, in S2, comparing the mechanical performance status value with a preset threshold to determine whether the gas cylinder is in a safe state may include: comparing the mechanical performance status value with the preset threshold to determine whether the mechanical performance status value is greater than the preset threshold; if so, the gas cylinder is close to safety failure and is in a dangerous state; otherwise, the gas cylinder is in a safe state.

[0064] The preset threshold value can be determined by the following method: determine the state of each damaged test block according to the actual damage condition of the damaged test block, the state includes safe and dangerous, and the state of each damaged test block determined in this embodiment is shown in Table 1. Then select the maximum value of the mechanical property state values ​​corresponding to all damaged test blocks with a safe state as the preset threshold value.

[0065] S3: If the first judgment result is no, the mechanical properties of the fire-affected part are determined according to the metallographic structure of the fire-affected part and the correspondence between the pre-established metallographic map and the mechanical properties; the mechanical properties are compared with the standard mechanical properties to determine whether the gas cylinder is in a safe state.

[0066] Before determining the mechanical properties of the fire-affected part according to the metallographic structure of the fire-affected part and the pre-established correspondence between the metallographic spectrum and the mechanical properties, the detection method of this embodiment further includes establishing the correspondence between the metallographic spectrum and the mechanical properties, which step may include:

[0067] (1) Prepare damage test pieces of gas cylinders at different fire temperatures;

[0068] (2) Observe the microstructure of the damaged test block and obtain the metallographic map of each damaged test block;

[0069] Specifically, the damaged test block was sanded and mechanically polished, then etched with 4% nitric acid alcohol, and then the microstructure of the damaged test block was observed according to GB / T 13298-2015 "Methods for the Examination of Metal Microstructures" to obtain the metallographic spectra of the damaged test block. The metallographic spectra of the damaged test blocks under various heat treatment conditions are as follows: Figure 3-Figure 8 As shown, Figure 3 The metallographic spectrum of the damaged specimen in the original state (i.e. without heat treatment); Figure 4 The metallographic spectrum of the damaged specimen obtained by keeping at 650℃ for 2 hours and air cooling; Figure 5 Metallographic spectrum of the damaged specimen obtained by keeping at 700℃ for 2 hours and air cooling; Figure 6 The metallographic spectrum of the damaged specimen obtained by keeping at 730℃ for 2 hours and air cooling; Figure 7 The metallographic spectrum of the damaged specimen obtained by keeping at 750℃ for 2 hours and air cooling; Figure 8 The metallographic spectrum of the damaged specimen obtained by keeping at 770℃ for 2 hours and air cooling; Fig. 9 Metallographic spectrum of the damaged specimen obtained by keeping at 800℃ for 2 hours and air cooling; Fig.10 Metallographic spectrum of the damaged specimen obtained by keeping at 850℃ for 2 hours and air cooling.

[0070] (3) performing a tensile test, an impact test, and a Brinell hardness test on the damaged test block to obtain mechanical properties of each damaged test block; the mechanical properties include yield strength, tensile strength, hardness, and impact work;

[0071] Specifically, for each damaged specimen, a tensile test is performed on the damaged specimen. A round rod specimen is selected for the tensile test. Therefore, round rod specimens are taken in the circumferential and axial directions on the damaged specimen, respectively, and recorded as circumferential specimens and axial specimens. According to GB / T 228.1-2010 "Tensile Test of Metallic Materials Part 1: Room Temperature Test Method", tensile tests are performed on circumferential specimens and axial specimens on a model Z250 electronic universal materials testing machine. All specimens are tested with an extensometer to measure the circumferential yield strength and circumferential tensile strength of circumferential specimens, and the axial yield strength and axial tensile strength of axial specimens. The yield strength of damaged specimens in various heat treatment states is as follows: Fig.11 As shown, the tensile strength is Fig.12 shown.

[0072] For each damaged test block, an impact test is performed on the damaged test block. The processing size of the impact test specimen is 10×10×55mm. Three specimens are prepared along the axial direction and circumferential direction of the gas cylinder, which are recorded as axial specimens and circumferential specimens. According to GB / T 229-2007 "Charpy Pendulum Impact Test Method for Metallic Materials", the axial specimens and circumferential specimens are impact tested on the model ZBC2452-CD pendulum impact testing machine. The test temperature is -40°C to measure the circumferential impact energy of the circumferential specimens and the axial impact energy of the axial specimens. The impact energy of the damaged test blocks in various heat treatment states is as follows: Fig.13 shown.

[0073] For each damaged test block, the Brinell hardness test was performed according to GB / T 231.1-2009 "Metallic Materials Brinell Hardness Test Part 1: Test Method". The hardness of the damaged test blocks in various heat treatment states is as follows: Fig.14 shown.

[0074] (4) Based on the metallographic spectra and mechanical properties of each damaged specimen, a corresponding relationship between the metallographic spectra and the mechanical properties is established.

[0075] After obtaining the correspondence between the metallographic map and the mechanical properties, determining the mechanical properties of the fire-affected part according to the metallographic structure of the fire-affected part and the pre-established correspondence between the metallographic map and the mechanical properties may include: comparing the metallographic map of the fire-affected part with the metallographic maps of damaged test blocks at different fire temperatures to determine the fire temperature of the fire-affected part; and determining the mechanical properties of the fire-affected part according to the fire temperature of the fire-affected part.

[0076] Comparing the mechanical properties with the standard mechanical properties to determine whether the gas cylinder is in a safe state may include: comparing the mechanical properties with the standard mechanical properties to determine whether the mechanical properties are within a threshold range of the standard mechanical properties, where the threshold range of the standard mechanical properties is given by the gas cylinder manufacturing standard. If so, the gas cylinder is in a safe state; otherwise, the gas cylinder is in a dangerous state.

[0077] The comparison results of mechanical properties corresponding to various heat treatment states and standard mechanical properties are shown in Table 2:

[0078] Table 2

[0079]

[0080] In Table 2, × indicates that the mechanical properties are lower than the lower limit, and ×× indicates that the mechanical properties are higher than the upper limit.

[0081] According to Table 2, after determining the fire temperature of the fire-affected part according to the metallographic spectrum of the fire-affected part, this embodiment can directly determine whether the gas cylinder is in a safe state according to the fire temperature and Table 2.

[0082] The detection method provided in this embodiment first compares the metallographic structure of the fire-affected part and the non-fire-affected part. If the metallographic structure is inconsistent, the corresponding mechanical property state value is queried according to the metallographic structure map after heat treatment. If the metallographic structure is consistent, magnetic multi-parameter detection is performed to determine the mechanical properties of the fire-affected part of the gas cylinder, so as to conduct a safety evaluation. The advantage of this method is that the microstructure and corresponding mechanical property relationship of the long-tube trailer gas cylinder at different temperatures is formed by heat treatment simulation, and the magnetic multi-parameter signal detection of each state is combined with the magnetic multi-parameter to form an expression. Compared with the existing inspection and evaluation methods, the performance characterization and quantification of the gas cylinder materials at different fire temperatures are no longer based on subjective judgment of the safety of the gas cylinder. In the on-site inspection of the long-tube trailer gas cylinder that has experienced a fire, the safety of the gas cylinder can be determined by the map for the metallographic structure changes in the fire-affected part; and for the metallographic structure that has not changed, the existing inspection method cannot make a judgment. The method of this embodiment makes up for the shortcomings of the existing inspection method through magnetic multi-parameter detection technology, reduces the possibility of missed detection of problem gas cylinders, and improves the reliability of safety evaluation of fire long-tube trailer gas cylinders, and has certain practical application value.

[0083] Embodiment 2:

[0084] This embodiment is used to provide a post-fire long-tube trailer gas cylinder safety detection system. Fig.15 As shown, the detection system comprises:

[0085] The metallographic structure comparison module M1 is used to perform metallographic inspection on the gas cylinder of the long tube trailer after the fire, determine whether the metallographic structures of the fire-affected part and the non-fire-affected part of the gas cylinder are consistent, and obtain a first determination result;

[0086] The magnetic multi-parameter determination module M2 is used for, if the first judgment result is yes, performing magnetic multi-parameter detection on the fire-affected part to obtain a magnetic multi-parameter characteristic signal; and using the magnetic multi-parameter characteristic signal as input, obtaining a mechanical property state value corresponding to the fire-affected part by using a multivariate linear regression equation; comparing the mechanical property state value with a preset threshold value to determine whether the gas cylinder is in a safe state; the magnetic multi-parameter detection includes magnetic Barkhausen noise detection, multi-frequency eddy current detection, incremental magnetic permeability detection and tangential magnetic field harmonic detection; the multivariate linear regression equation is used to characterize the correlation between the magnetic multi-parameter characteristic signal and the mechanical property state value;

[0087] The metallographic map determination module M3 is used to determine the mechanical properties of the fire-affected part according to the metallographic structure of the fire-affected part and the correspondence between the pre-established metallographic map and the mechanical properties if the first judgment result is no; and compare the mechanical properties with the standard mechanical properties to determine whether the gas cylinder is in a safe state.

[0088] Each embodiment in this specification focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0089] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is 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 method for safety detection of gas cylinders in a long-tube trailer after a fire, characterized in that: The detection method comprises: Performing metallographic inspection on the gas cylinder of the long tube trailer after the fire to determine whether the metallographic structures of the fire-affected part and the non-fire-affected part of the gas cylinder are consistent, thereby obtaining a first determination result; If the first judgment result is yes, a magnetic multi-parameter detection is performed on the fire-affected part to obtain a magnetic multi-parameter characteristic signal; and the magnetic multi-parameter characteristic signal is used as input to obtain a mechanical property state value corresponding to the fire-affected part using a multivariate linear regression equation; the mechanical property state value is compared with a preset threshold value to determine whether the gas cylinder is in a safe state; the magnetic multi-parameter detection includes magnetic Barkhausen noise detection, multi-frequency eddy current detection, incremental magnetic permeability detection and tangential magnetic field harmonic detection; the multivariate linear regression equation is used to characterize the correlation between the magnetic multi-parameter characteristic signal and the mechanical property state value; If the first judgment result is no, determining the mechanical properties of the fire-affected part according to the metallographic structure of the fire-affected part and the correspondence between the pre-established metallographic map and the mechanical properties; comparing the mechanical properties with the standard mechanical properties to determine whether the gas cylinder is in a safe state; The performing magnetic multi-parameter detection on the fire affected part to obtain the magnetic multi-parameter characteristic signal specifically comprises: Performing magnetic multi-parameter detection on the fire affected part to obtain a multi-parameter detection electromagnetic signal; Filtering, separating and transforming the multi-parameter detection electromagnetic signal to obtain a processed signal; Performing feature extraction on the processed signal to obtain a magnetic multi-parameter feature signal; the magnetic multi-parameter feature signal includes the amplitude and envelope characteristics of the magnetic Barkhausen noise signal, the impedance amplitude and phase of the multi-frequency eddy current signal, the curve width and amplitude of the incremental permeability signal, and the harmonic amplitude and phase of the magnetic field harmonic signal; Before using the magnetic multi-parameter characteristic signal as input to obtain the mechanical property state value corresponding to the fire-affected part using a multivariate linear regression equation, the detection method further includes establishing a multivariate linear regression equation, specifically including: Prepare damage test pieces of gas cylinders at different fire temperatures; Calibrate the state value of the damaged test block to obtain the mechanical property state value corresponding to each damaged test block; the state value calibration includes testing the mechanical properties of the damaged test block and comparing the mechanical properties with the standard; Performing magnetic multi-parameter detection on the damaged test blocks to obtain magnetic multi-parameter characteristic signals corresponding to each damaged test block; An initial multiple linear regression equation is established using the magnetic multi-parameter characteristic signal as an independent variable and the mechanical property state value as a dependent variable; Taking the mechanical property state value and the magnetic multi-parameter characteristic signal corresponding to each damaged test block as input, determining the model parameters of the initial multiple linear regression equation to obtain the multiple linear regression equation; The step of comparing the mechanical property state value with a preset threshold value to determine whether the gas cylinder is in a safe state specifically includes: Compare the mechanical property state value with a preset threshold value to determine whether the mechanical property state value is greater than the preset threshold value; If so, the gas cylinder is in a dangerous state; Otherwise, the gas cylinder is in a safe state.

2. The detection method according to claim 1, characterized in that Before comparing the mechanical property state value with the preset threshold, the detection method further includes determining the preset threshold, specifically including: Determine the state of each damaged test block according to the actual damage condition of the damaged test block; the state includes safe and dangerous; The maximum value of the mechanical property state values ​​corresponding to all the damaged test blocks whose states are safe is selected as the preset threshold.

3. The detection method according to claim 1, characterized in that: Before determining the mechanical properties of the fire-affected part according to the metallographic structure of the fire-affected part and the pre-established correspondence between the metallographic spectrum and the mechanical properties, the detection method further includes establishing the correspondence between the metallographic spectrum and the mechanical properties, specifically including: Prepare damage test pieces of gas cylinders at different fire temperatures; Conducting microstructural observation on the damaged test blocks to obtain a metallographic spectrum of each damaged test block; The damaged test blocks are subjected to a tensile test, an impact test and a Brinell hardness test respectively to obtain mechanical properties of each damaged test block; the mechanical properties include yield strength, tensile strength, hardness and impact work; According to the metallographic spectrum and mechanical properties of each damaged test block, a corresponding relationship between the metallographic spectrum and the mechanical properties is established.

4. The detection method according to claim 1, characterized in that: Determining the mechanical properties of the fire-affected part according to the metallographic structure of the fire-affected part and the correspondence between the pre-established metallographic map and the mechanical properties specifically includes: Comparing the metallographic structure of the fire-damaged part with the metallographic spectra of damaged test blocks at different fire temperatures to determine the fire temperature of the fire-damaged part; The mechanical properties of the fire-affected part are determined according to the fire-affected temperature of the fire-affected part.

5. The detection method according to claim 1 or 3, characterized in that: The preparation of damaged test blocks of gas cylinders at different fire temperatures specifically includes: Cut the gas cylinder to obtain multiple samples; The samples are heat treated, each of the samples corresponds to a heat treatment state, and damaged test blocks under multiple heat treatment states are obtained; the damaged test blocks under different heat treatment states are damaged test blocks under different fire temperatures.

6. The detection method according to claim 1, characterized in that: The comparing the mechanical properties with the standard mechanical properties to determine whether the gas cylinder is in a safe state specifically includes: Comparing the mechanical properties with standard mechanical properties to determine whether the mechanical properties are within a threshold range of the standard mechanical properties; If yes, the gas cylinder is in a safe state; Otherwise, the gas cylinder is in a dangerous state.

7. A post-fire long-tube trailer gas cylinder safety detection system, characterized in that: The detection system comprises: A metallographic structure comparison module is used to perform a metallographic inspection on the gas cylinder of the long tube trailer after the fire, determine whether the metallographic structures of the fire-affected part and the non-fire-affected part of the gas cylinder are consistent, and obtain a first determination result; A magnetic multi-parameter determination module, for, if the first judgment result is yes, performing magnetic multi-parameter detection on the fire-affected part to obtain a magnetic multi-parameter characteristic signal; and using the magnetic multi-parameter characteristic signal as input, obtaining a mechanical property state value corresponding to the fire-affected part by using a multivariate linear regression equation; comparing the mechanical property state value with a preset threshold value to determine whether the gas cylinder is in a safe state; the magnetic multi-parameter detection includes magnetic Barkhausen noise detection, multi-frequency eddy current detection, incremental magnetic permeability detection and tangential magnetic field harmonic detection; the multivariate linear regression equation is used to characterize the correlation between the magnetic multi-parameter characteristic signal and the mechanical property state value; a metallographic spectrum determination module, for determining the mechanical properties of the fire-affected part according to the metallographic structure of the fire-affected part and the pre-established correspondence between the metallographic spectrum and the mechanical properties if the first judgment result is no; and comparing the mechanical properties with standard mechanical properties to determine whether the gas cylinder is in a safe state; The performing magnetic multi-parameter detection on the fire affected part to obtain the magnetic multi-parameter characteristic signal specifically comprises: Performing magnetic multi-parameter detection on the fire affected part to obtain a multi-parameter detection electromagnetic signal; Filtering, separating and transforming the multi-parameter detection electromagnetic signal to obtain a processed signal; Performing feature extraction on the processed signal to obtain a magnetic multi-parameter feature signal; the magnetic multi-parameter feature signal includes the amplitude and envelope characteristics of the magnetic Barkhausen noise signal, the impedance amplitude and phase of the multi-frequency eddy current signal, the curve width and amplitude of the incremental permeability signal, and the harmonic amplitude and phase of the magnetic field harmonic signal; Before using the magnetic multi-parameter characteristic signal as input and obtaining the mechanical property state value corresponding to the fire-affected part by using the multivariate linear regression equation, the detection system further includes establishing a multivariate linear regression equation, specifically including: Prepare damage test pieces of gas cylinders at different fire temperatures; Calibrate the state value of the damaged test block to obtain the mechanical property state value corresponding to each damaged test block; the state value calibration includes testing the mechanical properties of the damaged test block and comparing the mechanical properties with the standard; Performing magnetic multi-parameter detection on the damaged test blocks to obtain magnetic multi-parameter characteristic signals corresponding to each damaged test block; An initial multiple linear regression equation is established using the magnetic multi-parameter characteristic signal as an independent variable and the mechanical property state value as a dependent variable; Taking the mechanical property state value and the magnetic multi-parameter characteristic signal corresponding to each damaged test block as input, determining the model parameters of the initial multiple linear regression equation to obtain the multiple linear regression equation; The step of comparing the mechanical property state value with a preset threshold value to determine whether the gas cylinder is in a safe state specifically includes: Compare the mechanical property state value with a preset threshold value to determine whether the mechanical property state value is greater than the preset threshold value; If so, the gas cylinder is in a dangerous state; Otherwise, the gas cylinder is in a safe state.

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