Environmental simulation accelerated corrosion test method for spray splash zone
By screening key environmental factors, statistical environmental spectra, and establishing equivalent conversion methods, combined with a multi-factor coupled test chamber, the problem of rapid and accurate evaluation of corrosion performance in the splash zone was solved, and the acceleration ratio relationship with the actual environment was realized, thus meeting the requirements for rapid evaluation of material service performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-03
- Publication Date
- 2026-03-10
AI Technical Summary
Existing technologies cannot quickly and accurately evaluate the corrosion performance of materials in the splash zone, natural environment exposure tests are time-consuming, and indoor simulation methods are not sufficient to reproduce the actual environment.
By screening key environmental factors, statistically forming an environmental spectrum, establishing an equivalent conversion method, conducting simulated accelerated corrosion tests, and combining this with a multi-factor coupled test chamber for indoor simulation, the acceleration ratio is analyzed to rapidly evaluate the corrosion performance of materials.
It enables rapid and accurate evaluation of the corrosion performance of materials in the splash zone, provides an acceleration ratio relationship with the actual environment, and meets the need for rapid evaluation of the service performance of materials.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of corrosion performance evaluation technology, and in particular to a method for accelerating corrosion testing by simulating the environment of a splash zone. Background Technology
[0002] The splash zone, due to factors such as frequent wet-dry cycles, high temperature, high humidity, high salt concentration, wave impact, and solar radiation, is the most severely corroded zone among the five corrosion zones in actual marine environments, with corrosion rates reaching 5-10 times that of the fully immersed zone. Natural exposure testing of the splash zone in the marine atmospheric environment is a widely used method; however, natural exposure is a long-term, continuous process and cannot meet the needs for rapid evaluation of material service performance. Therefore, it is crucial to establish targeted rapid evaluation methods for material adaptability, enabling accelerated prediction of long-term corrosion behavior and service life from short-term indoor testing.
[0003] Indoor simulated splash zone testing methods include wet-dry alternation tests, salt spray tests, and multi-factor coupled accelerated tests. Multi-factor coupled testing differs from traditional single-factor corrosion simulation; the constructed environment can reproduce the harsh corrosive environment of reality to the greatest extent possible, and different factors can be individually controlled, thus enhancing the reliability of the test data and the flexibility of the test scheme. Currently, simulated splash zone corrosion methods are still insufficient to accurately reproduce the actual environment and are at a relatively basic stage. Therefore, it is necessary to develop new simulated splash zone testing devices and corrosion testing evaluation methods. Summary of the Invention
[0004] The purpose of this invention is to provide a method for simulating accelerated corrosion testing in the splash zone environment. This method involves screening key environmental factors affecting the splash zone, statistically generating an environmental spectrum, establishing an equivalent conversion method based on the environmental spectrum, forming a simulated accelerated corrosion test spectrum for the splash zone, conducting real-sea and simulated tests, comparing and analyzing the results, determining the acceleration ratio, and performing indoor simulated accelerated corrosion evaluation. This method has the advantage of rapidly and accurately evaluating the corrosion performance of materials in the splash zone.
[0005] To achieve the above objectives, the present invention provides the following solution: a method for simulating accelerated corrosion testing in a splash zone environment, comprising the following steps: A method for simulating accelerated corrosion testing in a splash zone environment includes the following steps: S1. Based on corrosion test data of natural environment and simulated marine environment in the literature, a series of corresponding material properties, environmental factors and corrosion state data were sorted out. Through data processing algorithms, the importance of environmental factors affecting the corrosion rate and corrosion behavior of the splash zone were evaluated respectively. S2. Collect recent marine atmospheric and marine meteorological data, perform extreme value checks and consistency checks on the data, and statistically analyze the quantification range and changes of atmospheric environmental values based on the environmental characteristics of the splash zone, such as temperature, humidity, and ultraviolet radiation, to form an atmospheric environmental accumulation spectrum for the splash zone; and statistically analyze the quantification range and changes of marine environmental values based on the characteristics of alternating wet and dry seawater and splash frequency in the splash zone to form a marine environmental accumulation spectrum for the splash zone. S3. By equivalent conversion of the effective corrosion process of atmospheric and seawater environment in the splash zone, determine the corresponding test environment parameters and cycle combinations, and strengthen the synergistic control conditions of temperature, humidity, wet-dry alternation, splash frequency and other factors that have a significant impact on corrosion acceleration. S4. Conduct corrosion tests on the hanging plates in the actual sea splash zone, and arrange test samples for weight loss, morphology, electrochemical monitoring and other tests under different cycles to obtain corrosion evaluation data of the actual sea splash zone environment; S5. Conduct indoor simulated accelerated corrosion tests, arrange test samples for weight loss, morphology, electrochemical monitoring and other tests under different cycles, and use a multi-factor coupled corrosion test chamber to conduct indoor simulated splash zone accelerated corrosion tests to obtain corrosion evaluation data of the simulated splash zone environment. S6. Correlation analysis was performed on the data from the actual sea test in the splash zone and the data from the indoor accelerated simulation test. The acceleration ratio was determined based on the results of the actual sea test and the indoor simulation test. Iterative optimization design was carried out on the data of various environmental factors. Based on the principle of consistency of corrosion rate, corrosion kinetic process and corrosion mechanism, a corrosion acceleration test spectrum with good equivalence and high acceleration ratio was established.
[0006] Furthermore, in step S1, an orthogonal experimental design is adopted. By setting up orthogonal experiments, four environmental factors with significant influence on the corrosion rate are analyzed: wet-dry time ratio, temperature, humidity, and splashing frequency.
[0007] Furthermore, in step S2, the atmospheric environment accumulation spectrum is calculated based on the average value of meteorological data and the cumulative duration; Based on water quality and hydrological data, the intensity, frequency, and duration of the effects of various parameters in the marine environment accumulation spectrum are statistically analyzed. Considering the characteristics of continuous wet-dry alternation and localized corrosion in the splash zone, the environmental corrosion characteristic parameters affecting the splash zone are determined.
[0008] Furthermore, in step S3, in the equivalent conversion of the effective effect of the atmospheric environment, the time used for a single simulated factor is determined by the cumulative duration of the environmental spectrum and the conversion factor of the material and the solution used. In the equivalent conversion of the effective effects of the seawater environment, the time required for a single simulation factor is determined by the cumulative duration of the environmental spectrum and the corrosion sensitivity of the material in the seawater medium.
[0009] Furthermore, in step S4, the sea trial includes a parallel sample for calculating the corrosion rate, a test sample for analyzing the corrosion morphology and corrosion products, in order to obtain data on electrochemical impedance spectroscopy and polarization curves, and an array electrode sample for obtaining corrosion current density.
[0010] Furthermore, in step S5, an indoor simulated accelerated corrosion test is carried out, including a parallel sample for calculating the corrosion rate, test samples for corrosion morphology and corrosion product analysis, and data on electrochemical impedance spectroscopy and polarization curves, as well as array electrode samples for obtaining corrosion current density.
[0011] Furthermore, in step S6, the acceleration ratio is calculated through actual sea tests and simulations. Quantitative analysis is performed using corrosion current density, corrosion rate, and corrosion damage values; qualitative analysis is performed by comparing corrosion product types and corrosion morphology.
[0012] In the quantitative analysis, the amount of metal corrosion Q in the accelerated environment of the indoor test will be compared with the amount of metal corrosion Q' in the actual service environment. Letting Q = Q', the equivalent acceleration relationship between the two environments can be obtained:
[0013] In the formula: I c It is the corrosion current under accelerated indoor conditions, I' c It is the corrosion current under actual service conditions; Because of I c 、I' c As a function related to environmental factors (temperature, humidity, salt spray concentration), for the convenience of subsequent research, each environmental factor can be regarded as a constant value. According to the corrosion equivalence principle, the equivalent conversion factor α=Ic′ / Ic can be obtained, thereby establishing the correspondence between indoor accelerated test and actual natural service environment, so as to determine the acceleration ratio. Attached Figure Description
[0014] Figure 1 The corrosion rate of Q235 steel varies over different time periods.
[0015] Figure 2 The images show the submicroscopic 2D and 3D morphology of Q235 steel after pickling and rust removal under four corrosion cycles.
[0016] Figure 3 SEM images and EDS results of the rust layer surface of Q235 steel after 3 months, 6 months, 9 months and 12 months of corrosion in a real marine environment.
[0017] Figure 4Images showing the cross-sectional morphology and corresponding elemental distribution of rust layers on Q235 steel after 3 months (a), 6 months (b), 9 months (c), and 12 months (d) of corrosion in the splash zone.
[0018] Figure 5 The Nyquist plot (a) and Bode plot (b) of Q235 steel under different corrosion cycles in a real marine environment are shown.
[0019] Figure 6 Polarization curves of Q235 steel samples after 3, 6, 9, and 12 months of corrosion in the splash zone of marine seawater in 3.5 wt.% NaCl solution.
[0020] Figure 7 To simulate the change in corrosion rate of Q235 steel over time under splash corrosion conditions.
[0021] Figure 8 The equivalent circuit diagram for fitting the electrochemical impedance spectroscopy (EIS) of Q235 steel under simulated conditions is shown. Detailed Implementation
[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0023] The purpose of this invention is to provide a method for simulating accelerated corrosion testing in the splash zone environment. This method involves screening key environmental factors affecting the splash zone, statistically generating an environmental spectrum, establishing an equivalent conversion method based on the environmental spectrum, forming a simulated accelerated corrosion test spectrum for the splash zone, conducting real-sea and simulated tests, comparing and analyzing the results, determining the acceleration ratio, and performing indoor simulated accelerated corrosion evaluation. This method has the advantage of rapidly and accurately evaluating the corrosion performance of materials in the splash zone.
[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0025] In this embodiment, Q235 is used as the test sample, and the specific evaluation method is as follows: Step 1: Based on corrosion test data of natural environment and simulated marine environment in the literature, sort out a series of corresponding material properties, environmental factors and corrosion state data, and use data processing algorithms to evaluate the importance of environmental factors affecting the corrosion rate and corrosion behavior of the splash zone. In this embodiment, material properties, environmental factors, corrosion state data reported in the literature, and corrosion experimental data conducted through indoor simulation experiments were used. Six environmental factors were selected, each with three levels: pH (4, 6, 8), wet-dry time ratio (2:1, 4:1, 8:1), humidity (60%, 75%, 90%), salinity (0.5%, 3.5%, 5%), temperature (20℃, 30℃, 40℃), and splashing frequency (60s, 180s, 540s). Through orthogonal experiments, several groups of environmental factors with significant influence on corrosion rate were analyzed among the six environmental factors.
[0026] The table below shows the six-factor orthogonal experimental design: Table 1. Six-Factor Orthogonal Experiment Table
[0027] Multi-factor coupled accelerated corrosion tests were conducted using a designed orthogonal experiment. After each test cycle, weight loss data were recorded, and corrosion thickness loss data were calculated. To eliminate experimental errors, the weight loss data for each cycle was the average of three parallel samples. A power function D=A·tn was used for fitting the data. A difference analysis was performed on the n-value and corrosion rate of the orthogonal experiment to compare the weights of environmental factors on the n-value. The n-values are shown in Table 2.
[0028] The corrosion rate, measured by the weight loss method, varies depending on the duration of corrosion. As the rust layer continues to grow, its protective effect on the substrate changes, leading to variations in the weight of each factor affecting the corrosion rate at different time points. Range analysis of the corrosion rate data in Table 2 shows that the weights of the six environmental factors on the corrosion rate of Q235 steel, from largest to smallest, are: wet-dry ratio > temperature > humidity > splashing frequency > pH > salinity. Therefore, wet-dry ratio, temperature, humidity, and splashing frequency were selected as the experimental factors for indoor accelerated corrosion simulation.
[0029] Table 2. Results of orthogonal experiments on corrosion rate of Q235 steel
[0030] Step 2 involves collecting recent marine atmospheric and marine meteorological data, performing extreme value checks and consistency checks on the data to control data quality. For the environmental characteristics of the splash zone, such as temperature, humidity, and ultraviolet radiation, the quantification range and variation of atmospheric environmental values are statistically analyzed to form an atmospheric environmental accumulation spectrum for the splash zone. For the characteristics of alternating wet and dry seawater and splash frequency in the splash zone, the quantification range and variation of seawater environmental values are statistically analyzed, and a method for quantifying characteristic parameters is proposed to form a seawater environmental accumulation spectrum for the splash zone.
[0031] Since the splash zone is mostly in the atmospheric environment but also partially in the seawater environment, the environmental spectrum of the splash zone combines both atmospheric and seawater environmental data. Taking Qingdao as an example, atmospheric and seawater environmental data for the Qingdao area were collected and analyzed by the Atmospheric Test Station of the Qingdao Marine Corrosion Research Institute of the Iron and Steel Research Institute. Statistical results show that Qingdao has an average annual temperature of around 15°C and an average annual humidity of around 75%, classifying it as a typical North Temperate Monsoon Climate. The proportion of time with temperatures below 20°C and above 25°C is very small (below 20°C is counted as 20°C, and above 20°C is counted as 25°C). Therefore, the duration of temperature, humidity, and environmental factors such as rain and fog is mainly calculated based on the two temperature ranges of 20°C and 25°C. The results of the temperature and humidity spectrum and rain and fog spectrum are shown in Tables 3 and 4.
[0032] Table 3. Cumulative spectra of rain, fog, and humidity at the Qingdao Atmospheric Experiment Station
[0033] Table 4. Cumulative temperature and humidity spectra (h) at the Qingdao Atmospheric Test Station
[0034] After compiling the Qingdao marine atmospheric environment spectrum, the equivalent corrosion acceleration relationship and conversion factor of Q235 steel were used to formulate the indoor accelerated corrosion test spectrum for this type of material. The relevant conversion factors for Q235 steel in humid air and standard humid air can be obtained from existing research, as shown in Table 5.
[0035] Table 5 Conversion factors between humid air and standard humid air for Q235 carbon steel at different temperatures and humidity levels
[0036] According to the water corrosion environmental factor observation indicators from 2021 to 2024, the salinity of seawater has been maintained at around 3%, with a small deviation. Therefore, the salinity can be calculated using the annual salinity of 3%.
[0037] According to the Qingdao seawater environmental accumulation spectrum summarized by the 2021-2024 Water Corrosion Environmental Element Observation Index, the proportion of pH values below 7.5 or above 8.5 in a year is negligible (pH values between 7.5 and 8 are counted as 7.5, pH values between 8 and 8.5 are counted as 8, and pH values above 8.5 are counted as 8.5). Therefore, the duration of pH and salinity and other environmental factors was mainly calculated based on three temperature ranges: pH 7.5, 8, and 8.5. The pH accumulation spectrum results are shown in Table 6.
[0038] Table 6. Cumulative pH spectrum of seawater environment in Qingdao (h)
[0039] After compiling the pH and salinity accumulation spectrum of the Qingdao marine environment, the equivalent corrosion acceleration relationship and conversion factor of Q235 were used to formulate the indoor accelerated corrosion test spectrum for this type of material. Conversion factors for Q235 material at different mass fractions of NaCl solution and different pH values can be obtained from existing studies, as shown in Table 7.
[0040] Table 7. Conversion factors of Q235 for humid air and water media at different pH and salinity levels.
[0041] Step 3: By equivalent conversion of the effective corrosion process of atmospheric and seawater environment in the splash zone, determine the corresponding test environment parameters and cycle combinations, and strengthen the synergistic control conditions that significantly affect corrosion acceleration, such as temperature, humidity, wet-dry alternation, and splash frequency.
[0042] Taking a temperature of 40℃, humidity of 90%, wet-dry ratio of 4:1, and spray frequency of 180s as an example, the overall workflow is divided into three parts, each lasting 8 hours, with a 24-hour cycle. The first part is the humid heat stage, which allows for control of temperature and humidity. The second part is the spray stage, and the third part is the cyclic immersion stage, which cycles every 60 minutes, with a 12-minute immersion stage and a 48-minute drying stage.
[0043] Step 4: Conduct corrosion tests on the hanging plates in the actual sea splash zone, and arrange test samples for weight loss, morphology, electrochemical monitoring, etc. under different cycles to obtain corrosion evaluation data of the actual sea splash zone environment.
[0044] The marine exposure experiment was designed with four sampling cycles of 3 months, 6 months, 9 months and 12 months, and morphological observation, composition analysis and acid pickling and rust removal were carried out in sequence.
[0045] The corrosion rate variation of Q235 steel at different times is as follows: Figure 1 As shown, the corrosion trend exhibits a pattern of first decreasing and then increasing. The submicroscopic 2D and 3D morphological images after pickling and rust removal are shown below. Figure 2 As shown, after one year of corrosion (d), the surface underwent significant changes. The corrosion pits became larger and deeper, and the large corrosion pits intensified and merged into a ravine-like corrosion morphology, indicating the most severe corrosion.
[0046] SEM images and EDS images of rust layers after 3, 6, 9, and 12 months of corrosion in a real marine environment are shown. Figure 3 As shown. The cross-sectional morphology and corresponding elemental distribution diagram are shown below. Figure 4As the corrosion cycle lengthens, the rust layer thickness gradually increases under the same magnification. After 3 months of corrosion, there are no obvious corrosion pits on the substrate, but there are gaps between the rust layer and the substrate, and a small number of internal cracks. After 6 months, the gaps and cracks increase and the layers are separated. After 9 months, longitudinal and transverse cracks appear. After 12 months, there is loose floating rust on the surface.
[0047] The electrochemical results of the sample are shown in Figure 5 The Q235 steel exhibits a composite characteristic of a semi-circular capacitive arc in the low-frequency region and a diffusion tail in the high-frequency region, indicating that the corrosion process is controlled by both charge transfer and mass diffusion. Polarization curves of Q235 steel samples after 3, 6, 9, and 12 months of corrosion in the splash zone of actual seawater in 3.5 wt.% NaCl solution are shown below. Figure 6 The corrosion current density i was obtained by Tafel extrapolation. corr Listed in Table 8, the lower i corr This indicates that the rust layer has good corrosion resistance.
[0048] Table 8 Corrosion current density results obtained from fitting the polarization curve of Q235 steel in the splash zone.
[0049] Step 5: Conduct indoor simulated accelerated corrosion tests. Based on the accelerated corrosion test spectrum, arrange test samples for weight loss, morphology, electrochemical monitoring, etc. at different cycles. Use a multi-factor coupled corrosion test chamber to conduct indoor simulated splash zone accelerated corrosion tests to obtain corrosion evaluation data of the simulated splash zone environment.
[0050] The corrosion rate of Q235 steel under simulated splash corrosion conditions varies with time, as shown in the figure. Figure 7 The initial corrosion rate of Q235 steel is relatively high, but it gradually decreases thereafter. EIS results were obtained using... Figure 8 Perform fitting, where R s R is the resistance of the solution. f R is the resistance of the rust layer. ct , where represents the charge transfer resistance, W represents the diffusion impedance, and CPE1 and CPE2 are the non-ideal capacitance of the corrosion products on the steel surface of the sample and the parallel double-layer capacitance. The fitted values of the circuit components are shown in Table 9.
[0051] Table 9. Nyquist curve fitting results for Q235 steel under simulated conditions.
[0052] Polarization tests were performed on samples after 8 days of corrosion under simulated conditions. The corrosion current density i was obtained by Tafel extrapolation. corrAs shown in Table 10, the variation pattern of corrosion current is in good agreement with the actual corrosion rate. A high corrosion current density indicates a high corrosion rate.
[0053] Table 10 Corrosion current density results obtained from fitting the polarization curves of Q235 steel under simulated conditions.
[0054] Step 6: Conduct correlation analysis on the data from the actual sea test in the splash zone and the data from the indoor accelerated simulation test. Determine the acceleration ratio based on the results of the actual sea test and the indoor simulation test, and iteratively optimize the design of the data of various environmental factors. Based on the principle of consistency of corrosion rate, corrosion kinetic process, and corrosion mechanism, establish a corrosion acceleration test spectrum with good equivalence and high acceleration ratio.
[0055] The acceleration ratio was calculated through both real-sea and simulated tests. Qualitative analysis was performed using corrosion current density. The principle of corrosion current density can be summarized as follows: comparing the amount of metal corrosion Q in the accelerated testing environment with the amount of metal corrosion Q' in the actual service environment, i.e., comparing the amount of metal corrosion Q in the indoor accelerated testing environment with the amount of metal corrosion Q' in the actual service environment, and setting Q = Q', the equivalent acceleration relationship between the two environments can be obtained.
[0056] In the formula: I c It is the corrosion current under accelerated indoor conditions, I' c It is the corrosion current under actual service conditions; Because of I c 、I' c As a function related to environmental factors (temperature, humidity, salt spray concentration), for the convenience of subsequent research, each environmental factor can be regarded as a constant value. According to the corrosion equivalence principle, the equivalent conversion factor α = I can be obtained. c′ / I c The experiment collected corrosion current data under both marine and accelerated indoor environments using the Tafel extrapolation method. Based on the corrosion current data from both marine and accelerated indoor environments and the formula α=Ic′ / I c The equivalent conversion factor α was calculated to be 0.011, which means the acceleration factor is B = 90.91.
[0057] The absolute difference sequence of the initial values of the two types of steel after dimensionless processing is calculated according to formula (3). The absolute difference can reflect the magnitude of the difference between each factor, thereby helping to determine the degree of influence of each factor on the target factor. By calculating the absolute difference, the correlation between each factor and the target factor can be assessed more accurately, so as to make reasonable analysis and decisions. In formula (3), i represents two sets of accelerated tests.
[0058] The corrosion weight loss of Q235 steel exposed to the sea was set as the reference sequence X0, and the corrosion weight loss of three sets of indoor accelerated tests was set as the comparison sequence Xi. Table 11 shows the original corrosion weight loss data in the actual marine atmospheric environment and the indoor accelerated environment.
[0059] Table 11 Weight loss statistics of Q235 steel (g / m³) 2 )
[0060] The corrosion weight loss data from real-sea atmospheric exposure and indoor accelerated corrosion tests were dimensionless according to formulas (1) and (2). Then, the absolute difference sequence of the initial value series of the two steels after dimensionless treatment was calculated according to formula (3). Finally, the correlation coefficient and correlation degree of Q235 steel were calculated according to formulas (4) and (5). i represents three sets of accelerated tests, i=1, 2, ..., 9; k=1, 2, 3, 4.
[0061]
[0062] Calculations show that: Correlation degree between X1 and X0: γ01 = (1.000 + 1.000 + 0.821 + 0.855) / 4 = 0.919 Correlation degree between X2 and X0: γ02 = (1.000 + 0.716 + 0.932 + 0.486) / 4 = 0.784 The correlation between X3 and X0 is: γ03 = (1.000 + 0.794 + 0.586 + 0.333) / 4 = 0.678.
[0063] This application uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.
Claims
1. A method of a spatter zone environment simulation accelerated corrosion test, characterized by, Comprise the following steps: S1, based on the natural environment and simulated marine environment corrosion test data in the literature, comb a series of corresponding material properties, environmental factors, corrosion state data, through data processing algorithm, respectively, the importance of environmental factors affecting the splash zone corrosion rate and corrosion behavior evaluation; S2, collect the atmospheric and seawater meteorological data in recent years, check the extreme value of the data, check the consistency, according to the temperature, humidity, ultraviolet radiation and other environmental characteristics existing in the splash zone, statistical analysis of atmospheric environment value quantization interval and change, form the splash zone atmospheric environment accumulation spectrum; according to the characteristics of seawater dry and wet alternation, splash frequency existing in the splash zone, statistical analysis of seawater environment value quantization interval and change, form the splash zone seawater environment accumulation spectrum; S3, through the equivalent conversion of the effective action process of splash zone atmospheric and seawater environment corrosion, determine the corresponding test environment parameter conditions and cycle combination, strengthen the synergistic control conditions of temperature, humidity, dry and wet alternation, splash frequency and other factors which have significant influence on corrosion acceleration; S4, carry out real sea splash zone coupon corrosion test, arrange weight loss, morphology, electrochemical monitoring test samples under different periods, obtain corrosion evaluation data of real sea splash zone environment; S5, carry out indoor simulation accelerated corrosion test, arrange weight loss, morphology, electrochemical monitoring test samples under different periods, use multi-factor coupled corrosion test box to carry out indoor simulation splash zone accelerated corrosion test, obtain corrosion evaluation data of simulated splash zone environment; S6, correlation analysis is carried out on the real sea test data and indoor accelerated simulation test data. Through the real sea test results and indoor simulation test results, the acceleration ratio is determined, the environmental factor data is iteratively optimized and designed, and the corrosion acceleration test spectrum with good equivalence and high acceleration ratio is established based on the consistency of corrosion rate, corrosion kinetics process and corrosion mechanism.
2. The test method of claim 1, wherein, In step S1, through setting orthogonal test, 4 groups of environmental factors with greater influence weight on corrosion rate are analyzed by orthogonal experimental design: dry and wet time ratio, temperature, humidity and splash frequency.
3. The test method of claim 1, wherein, In step S2, the atmospheric environment accumulation spectrum is calculated according to the average value and duration of meteorological data; The seawater environment accumulation spectrum is calculated according to the water quality and hydrological data, the action strength, frequency and duration of each parameter are counted, and the environmental corrosion characteristic parameters affecting the splash zone are determined according to the characteristics of dry and wet alternation and local corrosion in the splash zone.
4. The test method of claim 1, wherein, In step S3, in the equivalent conversion of atmospheric environment effective action, the time used by single simulation factor is determined by the cumulative time of environmental spectrum and the conversion coefficient of material and used solution; In the equivalent conversion of seawater environment effective action, the time used by single simulation factor is determined by the cumulative time of environmental spectrum and the corrosion sensitivity of material in seawater medium.
5. The test method of claim 1, wherein, In step S4, the real sea test includes weight loss parallel sample for calculating corrosion rate, test sample for corrosion morphology and corrosion product analysis, in order to obtain electrochemical impedance spectrum, polarization curve data and array electrode sample for obtaining corrosion current density.
6. The test method of claim 1, wherein, In step S5, indoor simulation accelerated corrosion test is carried out, including weight loss parallel sample for calculating corrosion rate, test sample for analyzing corrosion morphology and corrosion product, data of electrochemical impedance spectrum and polarization curve can be obtained, and array electrode sample for obtaining corrosion current density.
7. The test method of claim 1, wherein, In step S6, the acceleration ratio is obtained by calculating the real sea and simulation test. Quantitative analysis is carried out through corrosion current density, corrosion rate and corrosion damage value; qualitative analysis is carried out through corrosion product type and corrosion morphology comparison; In quantitative analysis, the metal corrosion amount Q in the indoor test accelerated environment is compared with the metal corrosion amount Q' in the actual service environment, and Q = Q' is obtained, so that the equivalent acceleration relationship in the two environments can be obtained: ； wherein: I c is the corrosion current in the indoor accelerated environment, I' c is the corrosion current in the actual service environment; Due to I c , I' c is a function related to environmental factors (temperature, humidity, salt fog concentration). For the convenience of subsequent research, each environmental factor can be regarded as a constant value. According to the corrosion equivalence principle, the equivalent conversion coefficient α = Ic' / Ic can be obtained, and thus the corresponding relationship between indoor accelerated test and actual natural service environment is established to determine the acceleration ratio.