A method for judging corrosion risk of a dissimilar material mixed structure

Abstract

The application relates to a heterogeneous material mixed structure corrosion risk judgment method. A plurality of sample structures are subjected to detection tests to obtain a test database; then, a corrosion model and a risk model are established according to the test database, and a standard risk value is obtained; then, actual measured data of an actual piece are obtained, and the actual piece is judged whether to need protection treatment in combination with the corrosion model and the risk model. In the above steps, data obtained by traditional electrochemical tests and neutral salt spray tests are associated to obtain a relationship formula, so that when it is needed to judge whether the actual piece needs protection treatment, the corrosion potential difference and the corrosion current ratio obtained by galvanic corrosion risk simulation operation can be used to judge the corrosion risk, the corrosion risk of the actual piece of the heterogeneous material is quickly and effectively judged, and accurate machining standards are provided in a vehicle development process.

Description

Technical Field

[0001] This application relates to the field of metal corrosion technology, and in particular to a method for determining the corrosion risk of mixed structures of dissimilar materials. Background Technology

[0002] Currently, corrosion damages the appearance of automotive products, leading to functional failures, serious safety performance malfunctions, shortened service life, and affecting the residual value of used cars. From 2005 to 2020, more than 6.18 million vehicles in my country were recalled due to corrosion quality defects, involving 46 brands and more than 100 models. Serious safety performance malfunctions caused by corrosion are the most common reason for recalls, accounting for 91.3% of all corrosion-related vehicle recalls.

[0003] In some related technologies, steel-aluminum connections, as typical dissimilar material connection structures, are susceptible to galvanic corrosion, which cannot be ignored. Galvanic corrosion can further induce pitting corrosion and crevice corrosion, and when combined with external forces, it can easily cause more dangerous corrosion damage such as wear corrosion and stress corrosion, thereby reducing the lifespan of parts or components and affecting the long-term safety of automobiles. Therefore, research on anti-corrosion technologies for steel-aluminum connections is urgently needed.

[0004] In other related technologies, lightweighting has become an irreversible trend in automotive product development, and replacing steel parts with aluminum alloy parts is an important means of achieving automotive lightweighting. The proportion of aluminum alloys used in automobiles is increasing year by year, and steel-aluminum connection structures are also becoming more and more common; therefore, when performing corrosion protection on the whole vehicle, it is difficult to determine the galvanic corrosion risk of the steel-aluminum connection structure, and it is impossible to determine whether additional protection is needed. Summary of the Invention

[0005] This application provides a method for determining the corrosion risk of heterogeneous hybrid structures, in order to solve the problem in related technologies that it is difficult to effectively determine the galvanic corrosion risk of steel-aluminum connection structures when performing corrosion protection on the whole vehicle, and it is impossible to determine whether additional protection is needed.

[0006] Firstly, a method for assessing the corrosion risk of hybrid structures made of dissimilar materials is provided, which includes:

[0007] Electrochemical and neutral salt spray tests were conducted on various sample structures to obtain an experimental database.

[0008] A corrosion model and a risk model were established based on the aforementioned experimental database;

[0009] Obtain actual measured data of the actual component, and then calculate the actual risk value of the actual component based on the measured data, corrosion model, and risk model; the measured data includes the actual corrosion potential difference and the actual corrosion current.

[0010] Based on the established rules and the actual risk value, it is determined whether the actual component requires protective treatment.

[0011] In some embodiments, determining whether a physical component requires protective treatment based on set rules and the actual risk value includes the following steps:

[0012] Obtain the standard risk value for the actual part;

[0013] Compare the actual risk value of the actual part with the corresponding standard risk value;

[0014] If the actual risk value is greater than the standard risk value, the actual component is at risk of failure and requires protective measures.

[0015] If the actual risk value is less than the standard risk value, then the actual component does not require protective treatment.

[0016] In some embodiments, if there is a risk of failure in the actual component, the following steps are also included:

[0017] Calculate the difference between the actual risk value and the standard risk value;

[0018] The difference is compared with the first threshold, the second threshold, and the third threshold; the first threshold and the second threshold are greater than the first threshold, and the third threshold is greater than the second threshold;

[0019] If the difference is between the standard risk value and the first threshold, then Level 1 protection measures are applied.

[0020] If the difference is between the first threshold and the second threshold, then secondary protection is applied.

[0021] If the difference is between the second and third thresholds, then level three protection is applied.

[0022] If the difference is greater than the third threshold, then level four protection will be applied.

[0023] In some embodiments, each of the sample structures includes a first sample and a second sample; the first sample and the second sample are made of different materials;

[0024] Electrochemical and neutral salt spray tests were conducted on various sample structures to obtain a test database, including the following steps:

[0025] Electrochemical tests include electrode potential testing and galvanometer current detection testing;

[0026] Electrode potential tests were performed on each sample structure to obtain the test corrosion potential of the first and second samples; galvanic current detection tests were performed on each sample structure to obtain the test corrosion current of the first and second samples; and neutral salt spray tests were performed on each sample structure to obtain the test corrosion weight loss of the first and second samples.

[0027] The above test corrosion potential, test corrosion current, and test corrosion weight loss are used to form an experimental database.

[0028] In some embodiments, the following steps are included before performing electrochemical and neutral salt spray tests on various sample structures:

[0029] First, remove the corrosive medium from the first and second samples, then use copper foil tape to tightly bond the first and second samples together; or,

[0030] First, remove the corrosive medium from the first and second samples, and then connect the first and second samples using copper wires.

[0031] In some embodiments, establishing corrosion models and risk models based on the experimental database includes the following steps:

[0032] The test database is processed to obtain the test corrosion potential difference, test corrosion current ratio, and test corrosion weight loss ratio for each sample.

[0033] Establish a first curve and a second curve for each sample to form a corrosion model; the first curve is the relationship between the test corrosion potential difference and the test corrosion weight loss of the first sample or the test corrosion weight loss of the second sample; the second curve is the relationship between the test corrosion current ratio and the test corrosion weight loss ratio.

[0034] The risk model is established based on the test corrosion weight loss of the first sample and the test corrosion weight loss of the second sample.

[0035] In some embodiments, the test database is processed to obtain the test corrosion potential difference, test corrosion current ratio, and test corrosion weight loss ratio for each sample, including the following steps:

[0036] Calculate the difference between the test corrosion potential of the first and second samples in each type of sample, and use this difference as the test corrosion potential difference of that type of sample;

[0037] Calculate the first ratio between the test corrosion current of the first sample and the second sample in each type of sample, and use the first ratio as the test corrosion current ratio of that type of sample;

[0038] Calculate the second ratio between the test corrosion weight loss of the first and second samples in each type of sample, and use this second ratio as the test corrosion weight loss ratio of that type of sample.

[0039] In some embodiments, the actual component includes a first component and a second component;

[0040] Obtaining actual measurement data for real parts includes the following steps:

[0041] Perform galvanic corrosion risk simulation on actual components to obtain the actual corrosion potential and actual corrosion current of the first and second components.

[0042] The actual corrosion potential difference is calculated using the actual corrosion potentials of the first and second components; the actual corrosion current ratio is calculated using the actual corrosion currents of the first and second components.

[0043] The actual corrosion potential difference and the actual corrosion current ratio are used to form measured data.

[0044] In some embodiments, the actual risk value of the actual component is calculated based on the measured data, corrosion model, and risk model, including the following steps:

[0045] Based on the actual corrosion potential difference and corrosion model, the predicted corrosion weight loss of the first piece is obtained;

[0046] Based on the actual corrosion current ratio and corrosion model, the predicted corrosion weight loss ratio is obtained;

[0047] Based on the predicted corrosion weight loss ratio and the predicted corrosion weight loss of the first piece, the predicted corrosion weight loss of the second piece is obtained.

[0048] The actual risk value is derived based on the predicted corrosion weight loss of the second component and the predicted corrosion weight loss of the first component, as well as the risk model.

[0049] In some embodiments, the galvanic corrosion risk simulation operation includes the following steps:

[0050] The first and second pieces are bonded together, and then at a set temperature, saturated KCl droplets are used to completely cover the joint between the first and second pieces.

[0051] Then, the actual corrosion potential and actual corrosion current of the first and second parts at the connection point are measured using a testing instrument.

[0052] The beneficial effects of the technical solution provided in this application include:

[0053] This application provides a method for determining the corrosion risk of heterogeneous mixed structures. By conducting tests on various sample structures to obtain a test database, a corrosion model and a risk model are established based on the test database, and a standard risk value is obtained. Then, measured data from actual parts are obtained, and combined with the corrosion model and risk model, it can be determined whether the actual parts require protective treatment. In the above steps, data obtained from traditional electrochemical tests and neutral salt spray tests are correlated to obtain the relevant formula. Therefore, when it is necessary to determine whether an actual part requires protective treatment, only an electrochemical corrosion risk simulation operation is needed to obtain the potential difference and current ratio to determine the corrosion risk. This allows for a rapid and effective determination of the corrosion risk of heterogeneous material parts, providing accurate processing standards for vehicle development. Attached Figure Description

[0054] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0055] Figure 1 A schematic diagram of the first curve provided for an embodiment of this application;

[0056] Figure 2 A schematic diagram of the second curve provided in the embodiments of this application;

[0057] Figure 3 A schematic diagram of the general process for determining the corrosion risk of heterogeneous mixed structures provided in this application embodiment. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0059] The method and system for assessing the galvanic corrosion risk of a sealing coating, as described in Chinese patent application CN 114609031 A, involves measuring the electrochemical test data of the sealing coating system to be assessed, evaluating the galvanic corrosion pattern based on this data, obtaining the galvanic corrosion current, and thus determining the corrosion risk level. However, this method and system are only applicable to sealing coating systems and are not suitable for steel-aluminum hybrid connection structures. Furthermore, the simulation of galvanic corrosion risk is not very simple.

[0060] The comprehensive assessment method for external corrosion risk of buried pipelines in Chinese patent CN 109668820 B obtains basic external corrosion parameters (soil resistivity, pipeline natural corrosion potential, redox potential, soil pH, soil texture, soil moisture content, soil salinity, and soil Cl- content), scores each parameter individually, and calculates the corrosion risk after summarizing the results. This method is only applicable to assessing the corrosion risk of buried pipelines and not to assessing the corrosion risk of steel-aluminum hybrid connection structures, and it lacks a method for calculating galvanic corrosion intensity.

[0061] In addition, neutral salt spray testing is currently the most commonly used method for corrosion resistance testing, but the testing cycle is long and cannot meet the increasingly rapid development pace. Potentiodynamic polarization curve method and galvanic current detection test are the most basic and commonly used electrochemical testing methods, which can effectively characterize the intensity of electrochemical reactions of materials and have fast detection speed, but cannot determine their corrosion intensity and risk.

[0062] Therefore, it is necessary to utilize common tests and fewer tests in related technologies to make advance judgments on the corrosion risk of dissimilar material structures, in order to solve the problem that it is difficult to effectively determine the galvanic corrosion risk of steel-aluminum connection structures when performing corrosion protection on the whole vehicle, and to determine whether additional protection is needed.

[0063] A method for assessing corrosion risk in heterogeneous mixed structures, comprising:

[0064] Step S01: Conduct electrochemical and neutral salt spray tests on various sample structures to obtain a test database;

[0065] Step S02: Establish corrosion and risk models based on the experimental database;

[0066] Step S03: Obtain the measured data of the actual component, and then calculate the actual risk value of the actual component based on the measured data, corrosion model, and risk model; the measured data includes the actual corrosion potential difference and the actual corrosion current.

[0067] Step S04: Based on the set rules and actual risk values, determine whether the actual component needs protective treatment.

[0068] The above steps correlate data obtained from traditional electrochemical tests and neutral salt spray tests to obtain a relational formula, which serves as a reference standard. Therefore, when it is necessary to determine whether an actual part requires protective treatment, a simple galvanic corrosion risk simulation operation can be performed to obtain the potential difference and current ratio to determine the corrosion risk. This allows for a quick and effective assessment of the corrosion risk of actual parts made of dissimilar materials, providing accurate processing standards for vehicle development.

[0069] Step S04 specifically includes:

[0070] In some preferred embodiments, determining whether a physical component requires protective treatment based on set rules and actual risk values ​​includes the following steps:

[0071] S040. Obtain the standard risk value of the actual part;

[0072] S041. Compare the actual risk value of the actual part with the corresponding standard risk value;

[0073] S042. If the actual risk value is greater than the standard risk value, the actual part is at risk of failure and protective measures are required.

[0074] S043. If the actual risk value is less than the standard risk value, the actual part does not need to be protected.

[0075] In step S042, if the actual component has a risk of failure, the following steps are also included:

[0076] Calculate the difference between the actual risk value and the standard risk value;

[0077] The difference is compared with the first threshold, the second threshold, and the third threshold; the first threshold and the second threshold are greater than the first threshold, and the third threshold is greater than the second threshold;

[0078] If the difference is between the standard risk value and the first threshold, then Level 1 protection measures are applied.

[0079] If the difference is between the first threshold and the second threshold, then secondary protection is applied.

[0080] If the difference is between the second and third thresholds, then level three protection is applied.

[0081] If the difference is greater than the third threshold, then level four protection will be applied.

[0082] Step S01 specifically includes:

[0083] In some preferred embodiments, each sample structure includes a first sample and a second sample; the first sample and the second sample are made of different materials;

[0084] Electrochemical and neutral salt spray tests were conducted on various sample structures to obtain a test database, including the following steps:

[0085] Electrochemical tests include electrode potential testing and galvanometer current detection testing;

[0086] Electrode potential tests were performed on each sample structure to obtain the test corrosion potential of the first and second samples; galvanic current detection tests were performed on each sample structure to obtain the test corrosion current of the first and second samples; neutral salt spray tests were performed on each sample structure to obtain the test corrosion weight loss of the first and second samples; the above test corrosion potentials, test corrosion currents, and test corrosion weight losses were compiled into a test database.

[0087] Before conducting electrochemical and neutral salt spray tests on various sample structures, the following steps are included:

[0088] First, remove the corrosive medium from both the first and second samples, then use copper foil tape to tightly bond them together; alternatively, first remove the corrosive medium from both samples, then use copper wire to connect them. This approach takes into account the actual working environment of dissimilar material connection points in automobiles, and the possibility of corrosive medium accumulation has been ruled out in the initial design. This method avoids the situation of large amounts of corrosive medium accumulating in the gaps, and focuses on studying the galvanic corrosion between dissimilar materials.

[0089] Step S02 specifically includes:

[0090] The corrosion model and risk model are established based on the experimental database, specifically including the following steps:

[0091] S021. Process the test database to obtain the test corrosion potential difference, test corrosion current ratio and test corrosion weight loss ratio for each sample;

[0092] S022, Reference Figure 2 and Figure 1 A first and second curve are established for each sample to form a corrosion model. The first curve is the relationship between the test corrosion potential difference and the test corrosion weight loss of the first sample or the test corrosion weight loss of the second sample. The second curve is the relationship between the test corrosion current ratio and the test corrosion weight loss ratio. A risk model is established based on the test corrosion weight loss of the first sample and the test corrosion weight loss of the second sample.

[0093] Specifically, S021 includes processing the test database to obtain the test corrosion potential difference, test corrosion current ratio, and test corrosion weight loss ratio for each sample, including the following steps:

[0094] Calculate the difference between the test corrosion potentials of the first and second samples in each type of sample, and use this difference as the test corrosion potential difference of that type of sample; calculate the first ratio between the test corrosion currents of the first and second samples in each type of sample, and use this first ratio as the test corrosion current ratio of that type of sample; calculate the second ratio between the test corrosion weight loss of the first and second samples in each type of sample, and use this second ratio as the test corrosion weight loss ratio of that type of sample.

[0095] In step S03, in some preferred embodiments, the actual component includes a first component and a second component;

[0096] Obtaining actual measurement data for real parts includes the following steps:

[0097] A galvanic corrosion risk simulation operation was performed on the actual components to obtain the actual corrosion potential and actual corrosion current of the first and second components; the actual corrosion potential difference was calculated using the actual corrosion potential of the first and second components; the actual corrosion current ratio was calculated using the actual corrosion current of the first and second components; and the actual corrosion potential difference and actual corrosion current ratio were combined to form measured data.

[0098] In step S03, the actual risk value of the actual part is calculated based on the measured data, corrosion model, and risk model, including the following steps:

[0099] Based on the actual corrosion potential difference and the corrosion model, the predicted corrosion weight loss of the first component is obtained; based on the actual corrosion current ratio and the corrosion model, the predicted corrosion weight loss ratio is obtained; based on the predicted corrosion weight loss ratio and the predicted corrosion weight loss of the first component, the predicted corrosion weight loss of the second component is obtained; based on the predicted corrosion weight loss of the second component and the predicted corrosion weight loss of the first component, as well as the risk model, the actual risk value is obtained.

[0100] The galvanic corrosion risk simulation operation in the above steps includes the following steps:

[0101] The first and second pieces are bonded together, and then at a set temperature, saturated KCl droplets are used to completely cover the joint between the first and second pieces. Then, the actual corrosion potential and actual corrosion current of the first and second pieces at the joint are measured using a testing instrument.

[0102] A specific example is given below.

[0103] neutral salt spray test

[0104] The test was conducted using a salt spray chamber (requiring a corrosion intensity of 70±20 g / m², with an Ascott CC2000IP model recommended). The test was carried out according to the relevant requirements of GB / T10125-2012 "Artificial Atmosphere Corrosion Test: Salt Spray Test", specifically as follows: Salt spray collection solution concentration: NaCl: (5±0.5) wt%; Chamber temperature: (35±2)℃; Salt spray deposition rate: (1~2) ml / (80cm²). 2 •h); pH value of settling brine: 6.5~7.2.

[0105] Electrochemical tests include dynamic electrode potential testing and galvanometer current detection testing:

[0106] Dynamic electrode potential test

[0107] An electrochemical workstation (PS268A recommended) was used, with the following specific experimental parameters: Test system: three-electrode system; Reference electrode: Ag / AgCl; Counter electrode: platinum sheet electrode; Solution: saturated KCl solution; Solution volume: solution volume to sample area ratio greater than 50 mL / cm². 2 Sample size: 1cm × 1cm; Coating material: epoxy resin; Scanning speed: 60mV / min; Scanning range: -250 to +500mV based on self-corrosion potential;

[0108] Coupling current detection test

[0109] A galvanometer (ZRA-2 type galvanometer recommended) was used, and the specific test parameters were as follows: Reference electrode: Ag / AgCl electrode; Test solution: saturated KCl solution; Test temperature: room temperature 25℃; Working electrode: test sample.

[0110] Following the equipment and test parameters described in the above-mentioned galvanic current detection test, a galvanic current detection test was conducted to measure the self-corrosion current intensity of the material. Using the equipment and test parameters described in the dynamic electrode potential test, an electrochemical test was conducted using the potentiodynamic polarization method. A Tafel curve was plotted, and the self-corrosion potential and self-corrosion current density were calculated based on the relationship between the electrode polarization overpotential η and the polarization current density J under strong polarization conditions (as shown below).

[0111] η=a+blgJ

[0112] Where a and b are collectively referred to as Tafel constants, they are two important parameters characterizing the electrochemical performance of the electrode. a represents the overpotential of the electrode under unit current density; the smaller the value of a, the stronger the electrode's resistance to polarization. The value of a is related to the electrode material, electrode surface condition, solution concentration, and temperature. The value of b characterizes the degree of influence of changes in polarization current density on the electrode overpotential. Neutral salt spray tests were conducted using the equipment and test parameters described above. The test was divided into a control group and an experimental group. The control group consisted of two separate plates without a connecting structure, while the experimental group consisted of two plates with the connecting structure described in 1.1. The test cycle was 1000 hours. Before the test, the plates were cleaned, dried, and weighed. After the test, corrosion products were removed according to the relevant requirements of GB / T16545 "Removal of Corrosion Products from Corrosion Specimens of Metals and Alloys," weighed, and the mass loss was calculated.

[0113] The above experimental data should be processed using the following formula:

[0114] Corrosion potential difference: ΔE corr =E corrA –E corrB Corrosion current ratio: p icorr =i corrB / i corrA ; Coupling corrosion weight loss: m gc =m-m0; Coupling corrosion weight loss ratio: p mgc =m gcA / m gcB ; for △E corr -m gcA p icorr -p mgc Mathematical analysis was performed to construct a corrosion potential-corrosion intensity calculation model (i.e., a corrosion model).

[0115] For dissimilar material (steel-aluminum) connection structures, droplet aggregation during use will create a galvanic structure as shown in the figure, leading to the risk of galvanic corrosion.

[0116] To simplify the analysis, the following assumptions are made: the two materials are completely bonded; the droplet completely covers the joint surface, and the joint area does not come into contact with the atmosphere; only galvanic corrosion occurs at the joint; the degree of damage at the joint reaches level 2, which means there is a significant risk of failure.

[0117] Based on the above assumptions, if Do fqw A value >0.2 indicates severe galvanic corrosion, posing a risk of failure and requiring additional protective measures; if Do fqw If the value is less than 0.2, the galvanic corrosion is relatively minor and no additional treatment is required.

[0118] Based on the foregoing results, the risk assessment and countermeasure recommendations for galvanic corrosion at the connection between dissimilar materials (steel and aluminum) can be achieved by measuring the material's self-corrosion potential and self-corrosion current. The specific steps are as follows:

[0119] (1) Determine the self-corrosion potential E of the two materials A and B in the connecting structure. corrA E corrB Self-corrosion current i corrB i corrA ;

[0120] (2) Calculate the corrosion potential difference ΔE corr Corrosion current ratio p icorr galvanic corrosion weight loss m gc galvanic corrosion weight loss ratio p mgc ;

[0121] (3) Substituting into the corrosion model, we obtain m gcA =f(△E) corr ), pmgc = f(p icorr Calculate the weight loss m due to galvanic corrosion. gcA m gcB ;

[0122] (4) Substitute into the risk model Calculate the galvanic corrosion risk criterion factor (risk value) Do fqw ;

[0123] (5) Conduct galvanic corrosion risk assessment: If Do fqw A value >0.2 indicates severe galvanic corrosion, posing a risk of failure and requiring additional protective measures; if Do fqw If the value is less than 0.2, the galvanic corrosion is relatively minor and no additional treatment is required.

[0124] For example, during the development of one of our vehicle models, the body structure had a steel-aluminum hybrid connection structure, which required an assessment of the risk of galvanic corrosion in order to determine whether additional protection was needed in the design.

[0125] Taking into account common lightweight materials and our company's material usage, we selected two types of aluminum alloy plates, 5182 and 6082, and four types of steel plates, including bare plate (DC01), galvanized plate (DX51D+Z), zinc-aluminum-magnesium coated plate (DC01ZAM), and aluminum-silicon coated plate (D1300HF+AS), for a total of eight combinations, as shown in Table 1 below.

[0126]

[0127] Table 1

[0128] The results of the electrochemical tests are shown in Table 2 below.

[0129]

[0130]

[0131] The results of the neutral salt spray test are shown in Tables 3 and 4 below.

[0132]

[0133] Table 3 (Control Group - Single-Plate Test)

[0134]

[0135] Table 4 (Experimental Group - Sample Test) shows the results of processing the above test data, which is then presented in Table 5.

[0136] Table 5

[0137] Calculations are performed according to Table 5.

[0138] (1) △E corr -m gcA Relationship, see Figure 1 :m gcA =0.0003*△E corr +0.0816, R 2 =0.9633;

[0139] (2) p icorr -p mgc Relationship, see Figure 2 :p mgc =747.71*p icorr 3-484.28*p icorr 2+92.759*p icorr -3.1919, R 2 =0.967;

[0140] (3) Measurement of self-corrosion potential and self-corrosion current: E corrA = -1075mV, E corr B = -870mV, i corrA =121.7μA / cm 2 i corrB =5.9μA / cm 2 ;

[0141] △E corr = -205mV, p icorr =0.04; m gcA =0.0201g, p mgc =0.252,m gcB =0.080g;

[0142] (4) The calculation results of the galvanic corrosion risk criterion factor are: Do fqw =0.215;

[0143] (5) Galvanic corrosion risk assessment: Do fqw A value >0.2 indicates severe galvanic corrosion, posing a risk of failure and requiring additional protective measures.

[0144] Actual verification: Verification of the actual corrosion of the hybrid connection structure of aluminum plate (6061) and steel plate (D1300HF+AS), and the results of a 1000-hour neutral salt spray test on the riveted aluminum plate (6061) and steel plate (D1300HF+AS): obvious galvanic corrosion occurred between steel and aluminum, and the overall corrosion was relatively serious. In actual design, additional isolation protection is required to avoid the risk of galvanic corrosion.

[0145] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0146] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0147] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for assessing the corrosion risk of a mixed-material structure, characterized in that, It includes: Electrochemical and neutral salt spray tests were conducted on various sample structures to obtain an experimental database. Each of the aforementioned sample structures includes a first sample and a second sample; The first and second samples are made of different materials, and the first and second samples are connected. Obtaining the experimental database includes the following steps: electrochemical tests, including electrode potential testing and galvanic current detection testing; electrode potential testing is performed on each sample structure to obtain the test corrosion potential of the first and second samples; galvanic current detection testing is performed on each sample structure to obtain the test corrosion current of the first and second samples; neutral salt spray testing is performed on each sample structure to obtain the test corrosion weight loss of the first and second samples; the above test corrosion potentials, test corrosion currents, and test corrosion weight losses are used to form an experimental database. Based on the aforementioned test database, a corrosion model and a risk model are established. This step specifically includes the following steps: processing the test database to obtain the test corrosion potential difference, test corrosion current ratio, and test corrosion weight loss ratio for each sample; establishing a first curve and a second curve for each sample to form a corrosion model; the first curve is the relationship curve between the test corrosion potential difference and the test corrosion weight loss of the first sample or the test corrosion weight loss of the second sample; the second curve is the relationship curve between the test corrosion current ratio and the test corrosion weight loss ratio; and establishing the risk model based on the test corrosion weight loss of the first sample and the test corrosion weight loss of the second sample. Obtain measured data of actual components, and then calculate the actual risk value of the actual components based on the measured data, corrosion model, and risk model; the measured data includes the actual corrosion potential difference and the actual corrosion current; the actual components include a first component and a second component; obtaining the measured data of the actual components includes the following steps: performing a galvanic corrosion risk simulation operation on the actual components to obtain the actual corrosion potential and actual corrosion current of the first and second components; calculating the actual corrosion potential difference using the actual corrosion potential of the first and second components; calculating the actual corrosion current ratio using the actual corrosion current of the first and second components; and forming the measured data from the actual corrosion potential difference and the actual corrosion current ratio. The calculation of the actual risk value of the actual component includes the following steps: Based on the actual corrosion potential difference and the corrosion model, the predicted corrosion weight loss of the first component is obtained; based on the actual corrosion current ratio and the corrosion model, the predicted corrosion weight loss ratio is obtained; based on the predicted corrosion weight loss ratio and the predicted corrosion weight loss of the first component, the predicted corrosion weight loss of the second component is obtained; based on the predicted corrosion weight loss of the second component and the predicted corrosion weight loss of the first component, and the risk model, the actual risk value is obtained; the risk model is... ;in This represents the actual risk value. The predicted corrosion weight loss for the first piece; The predicted corrosion weight loss for the second component; The galvanic corrosion risk simulation operation includes the following steps: bonding the first and second pieces together, then completely covering the connection between the first and second pieces with saturated KCl droplets at a set temperature; then using a tester to measure the actual corrosion potential and actual corrosion current of the first and second pieces at the connection. Based on the established rules and the actual risk value, it is determined whether the actual component requires protective treatment.

2. The corrosion risk assessment method for dissimilar material hybrid structures as described in claim 1, characterized in that, Based on the established rules and the actual risk value, the determination of whether a physical component requires protective treatment includes the following steps: Obtain the standard risk value for the actual part; Compare the actual risk value of the actual part with the corresponding standard risk value; If the actual risk value is greater than the standard risk value, the actual component is at risk of failure and requires protective measures. If the actual risk value is less than the standard risk value, then the actual component does not require protective treatment.

3. The corrosion risk assessment method for dissimilar material hybrid structures as described in claim 2, characterized in that, If the actual component is at risk of failure, the following steps are also included: Calculate the difference between the actual risk value and the standard risk value; The difference is compared with the first threshold, the second threshold, and the third threshold; the second threshold is greater than the first threshold, and the third threshold is greater than the second threshold. If the difference is less than the first threshold, then level one protection is applied; If the difference is between the first threshold and the second threshold, then secondary protection is applied. If the difference is between the second and third thresholds, then level three protection is applied. If the difference is greater than the third threshold, then level four protection will be applied.

4. The corrosion risk assessment method for dissimilar material hybrid structures as described in claim 1, characterized in that, Before conducting electrochemical and neutral salt spray tests on various sample structures, the following steps are included: First, remove the corrosive medium from the first and second samples, then use copper foil tape to tightly bond the first and second samples together; or, First, remove the corrosive medium from the first and second samples, and then connect the first and second samples using copper wires.

5. The method for determining the corrosion risk of a mixed structure of dissimilar materials as described in claim 1, characterized in that, The test database is processed to obtain the test corrosion potential difference, test corrosion current ratio, and test corrosion weight loss ratio for each sample, including the following steps: Calculate the difference between the test corrosion potential of the first and second samples in each type of sample, and use this difference as the test corrosion potential difference of that type of sample; Calculate the first ratio between the test corrosion current of the first sample and the second sample in each type of sample, and use the first ratio as the test corrosion current ratio of that type of sample; Calculate the second ratio between the test corrosion weight loss of the first and second samples in each type of sample, and use this second ratio as the test corrosion weight loss ratio of that type of sample.

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