Method and device for simulating and calculating corrosion rate of metal material in fluorine-containing solid medium

Abstract

The invention provides a method and a device for simulating and calculating the corrosion rate of a metal material in a fluorine-containing solid medium. The method comprises the following steps: weighing a to-be-measured metal material, calculating the surface area of the to-be-measured metal material, embedding the to-be-measured metal material into a fluorine-containing solid medium, heating, preserving heat, simulating corrosion, naturally cooling, weighing, and calculating the corrosion rate of the to-be-measured metal material according to a formula C1 = 8000 * (M0-M1) / (rho * A * t). The invention further provides a corrosion simulation device for the simulation calculation method. The corrosion simulation device mainly comprises a heating cavity and a reaction cavity. The corrosion condition of the metal material in the solid fluoride in reality is simulated, the corrosion rate of the metal material in the solid fluoride can be accurately and rapidly calculated, data is provided for corrosion prevention of the metal material, and the corrosion conditions of the metal material at different temperatures can be simulated; the simulation calculation method provided by the invention is simple and easy to popularize.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal material protection, and particularly relates to a method and device for simulating and calculating the corrosion rate of metal materials in a fluorine-containing solid medium. Background Art

[0002] With the continuous development of the chemical industry, the corrosion problem of chemical equipment has become increasingly prominent. According to relevant reports, the failure of almost all equipment and devices in the petrochemical field is related to corrosion. At present, the materials resistant to the corrosion of fluorine, hydrogen fluoride gas or liquid in industrial applications are mostly platinum, nickel, Monel alloy, graphite or polytetrafluoroethylene, etc. The involved media are gas or liquid, and the temperature is relatively low. Regarding the adaptability, reliability and life prediction of metal materials in a fluorine-containing solid medium environment, there is currently a lack of basic and systematic data and it is difficult to evaluate. If the corrosion resistance of metal materials in a fluorine-containing solid medium can be calculated quickly and accurately, more targeted and effective protection measures can be taken for metal materials, providing an important scientific basis for the future maintenance and improvement of related products.

[0003] The evaluation of corrosion resistance is largely determined according to the results of corrosion tests. From the investigation of the corrosion causes of metal materials in different environments, the measurement of corrosion rates to the anti-corrosion of metal materials and the evaluation of anti-corrosion effects, the similarity between the simulated corrosion test and the corrosion environment faced by metal materials in reality, as well as the accuracy and efficiency of the simulated corrosion rate calculation are two extremely important aspects in corrosion simulation tests. Due to the change of the industrial environment, the corrosion environment of metal materials is different. Chinese invention patent CN102142063A discloses a method for calculating the long-term corrosion rate from short-term test results. By using a simulation experiment, the weight loss at different test times is obtained, and the corrosion rate is calculated through a calculation model after function simulation of the weight loss and time data. However, this method, on the one hand, the function simulation is too complex, and on the other hand, due to different environments, the difference in the corrosion of metals in different specific environments is relatively large. For example, metal materials often face a corrosion environment containing fluorine and high temperature. This method and traditional simulation corrosion methods cannot accurately evaluate the corrosion resistance of metal materials in this environment. Therefore, there is no method in the prior art that can evaluate the corrosion rate of metal materials in a long-term fluorine-containing and high-temperature corrosion environment.

[0004] Based on the problems existing in the prior art, a rapid calculation method for simulating the long-term corrosion environment of metal materials containing fluorine and high temperature is provided, which can accurately and quickly calculate the corrosion rate of metal materials, and provide data support for the anti-corrosion protection of actual metal materials by simulating the corrosion degree of metal materials in the environment. Summary of the Invention

[0005] The main object of the present invention is to provide a method and device for simulating and calculating the corrosion rate of metal materials in a fluorine-containing solid medium to overcome the deficiencies of the prior art.

[0006] To achieve the above technical object, the technical solution provided by the present invention is as follows:

[0007] As a first aspect of the present invention, there is provided a method for simulating and calculating the corrosion rate of a metal material in a fluorine-containing solid medium, which includes: weighing the metal material to be tested, calculating the surface area of the metal material to be tested, then burying the metal material to be tested in the fluorine-containing solid medium, heating and keeping warm for simulated corrosion, and after natural cooling, weighing the metal material to be tested to calculate the corrosion rate of the metal material to be tested;

[0008] The calculation formula is: C 1 = 8000*(M 0 - M 1 ) / (ρ*A*t), where C 1 is the corrosion rate, with the unit of mm / a; M 0 is the mass of the metal material to be tested before corrosion, with the unit of g; M 1 is the mass of the metal material to be tested after corrosion, with the unit of g; ρ is the density of the metal material to be tested, with the unit of g / mm 3 ; A is the surface area of the metal material to be tested, with the unit of mm 2 ; t is the simulated corrosion time, with the unit of h; 8000 is equivalent to the number of hours in a year. The calculation method and device for simulating and calculating the corrosion rate of a metal material in a fluorine-containing solid medium provided by the present invention can accurately and quickly calculate the corrosion rate of the metal material when simulating the long-term operation of the metal material in a working environment with a fluorine-containing solid medium and high temperature corrosion.

[0009] Further, the above method includes the following steps:

[0010] S1. Remove the surface oxide layer and impurities of the metal material to be tested, weigh it after drying, and calculate the surface area of the metal material to be tested.

[0011] S2. Fill the fluorine-containing solid medium in the simulated corrosion device, then bury the metal material to be tested in the fluorine-containing solid medium, heat and keep warm, and complete the simulated corrosion after natural cooling.

[0012] S3. Wash the metal material to be tested that has completed the simulated corrosion, and weigh it after drying.

[0013] S4. Calculate the corrosion rate of the metal material to be tested according to the above formula.

[0014] Furthermore, in S1, the surface of the metal material to be tested is polished and then cleaned with water and anhydrous ethanol to remove the surface oxide layer and impurities.

[0015] Furthermore, the fluorine-containing solid medium includes any one of non-metallic fluorides and metal fluorides, or a combination of both.

[0016] Furthermore, the non-metallic fluoride includes any one or more combinations of ammonium fluoride and ammonium bifluoride, but is not limited thereto.

[0017] Furthermore, the metal fluoride includes any one or more combinations of ammonium fluoroferrate, ammonium fluorosilicate, magnesium fluoride, and calcium fluoride, but is not limited thereto.

[0018] Furthermore, the metal material to be tested is buried in the fluorine-containing solid medium, and the distance to the surface of the fluorine-containing solid medium is greater than 2 cm.

[0019] Furthermore, in S1, the metal material to be tested is processed into a block sample and the surface is polished and cleaned to remove the surface oxide layer and impurities; preferably, the size of the block sample is (50-60)*(20-25)*(2-5), in units of mm.

[0020] Furthermore, in S2, the metal material to be tested is buried in the fluorine-containing solid medium, heated to 230°C-800°C and kept warm for 5h-10h, at which time the fluorine-containing solid medium is consumed, the metal material to be tested is taken out, and the fluorine-containing solid medium is added again to heat and keep warm, which is repeated 4-10 times, and the simulated corrosion is completed after natural cooling.

[0021] In an embodiment of the present invention, there is also provided a device for simulating the corrosion rate of a metal material in a fluorine-containing solid medium, comprising at least:

[0022] A reaction chamber for containing a fluorine-containing solid medium; and

[0023] A heating device for heating the reaction chamber;

[0024] A heat preservation device for maintaining a constant temperature of the reaction chamber;

[0025] When performing simulation, the fluorine-containing solid medium is filled in the reaction chamber, and then the metal material to be tested is buried in the fluorine-containing solid medium. The reaction chamber is heated by the heating device and kept warm by the heat preservation device.

[0026] Further, the heat preservation device is a heat preservation layer disposed on the outer wall of the reaction chamber; a cavity structure is formed between the heat preservation layer and the reaction chamber, and the cavity structure forms a heating chamber; the heating device is built in the heating chamber; preferably, the heating device is a heating wire uniformly distributed on the outer wall of the reaction chamber.

[0027] Compared with the prior art, the beneficial effects of the present invention are at least as follows:

[0028] 1. The method for simulating and calculating the corrosion rate of metal materials in a fluoride-containing solid medium provided by the present invention simulates the corrosion of metal materials in a high-temperature and solid fluoride corrosion medium, accurately and efficiently calculates the corrosion rate of metal materials in solid fluorides, and provides data support for the anti-corrosion protection of metal materials.

[0029] 2. The simulated corrosion process in the present invention is carried out in a simulated corrosion device, which is simple and easy to operate, has a high similarity to the corrosion environment faced by metal materials in reality, and can simulate the corrosion of metal materials at different temperatures. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0031] Figure 1 It is the SEM image of the metal material that has completed simulated corrosion in Embodiment 1 of the present application.

[0032] Figure 2 It is the structural schematic diagram of the simulated corrosion device in Embodiment 1 of the present application.

[0033] Figure 3 It is the electron microscope image of the metal material that has completed simulated corrosion in Embodiment 2 of the present application.

[0034] Figure 4 It is the SEM image of the metal material that has completed simulated corrosion in Embodiment 3 of the present application.

[0035] Figure 2 In [the figure], 1: handle; 2: heating wire; 3: heating chamber; 4: gas outlet; 5: furnace lid; 6: reaction chamber thermocouple; 7: heat preservation layer; 8: reaction chamber; 9: heating chamber thermocouple; 10: furnace shell. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] Detailed embodiments of the present invention are disclosed herein; however, it should be understood that the disclosed embodiments are merely exemplary of the present invention, which can be embodied in various forms. Therefore, the specific functional details disclosed herein should not be interpreted as limiting, but only as a basis for the claims and as a representative basis for teaching those skilled in the art to employ the present invention in various ways in virtually any appropriately detailed embodiment.

[0037] Example 1

[0038] This example simulates the corrosion of Monel-400 in ammonium fluoride at 230°C and calculates its corrosion rate, including:

[0039] (1) Sample preparation: Monel-400 was processed into a block sample with a size of 60 mm × 20 mm × 3 mm, and polished with 400#, 800#, 1200# sandpaper and metallographic sandpaper, and then cleaned and decontaminated with pure water and anhydrous ethanol. After drying, the sample was weighed with an electronic balance for later use. Its initial weight was recorded as M. 0 (g).

[0040] (2) Corrosion test: In this embodiment, the simulated corrosion process is carried out in a simulated corrosion device, see Figure 2 , is a structural diagram of the simulated corrosion device used in this embodiment, which includes a furnace body and a furnace cover 5. The furnace body is a cavity with at least one end open, and the furnace cover 5 is detachably arranged at the open end of the furnace body. Preferably, a heat preservation layer is provided inside the furnace cover 5, which can reduce heat loss of the simulated corrosion device during operation and maintain a constant temperature inside the furnace body.

[0041] The furnace body is provided with a heating chamber 3 and a reaction chamber, and the reaction chamber 8 is built in the heating chamber 3. A heat preservation layer 7 is provided in the furnace shell 10 of the furnace body, which can maintain the temperature in the furnace body at a constant temperature and reduce heat loss.

[0042] The furnace cover 5 is also provided with a gas outlet 4, which can discharge the gas generated during the reaction process, thereby simulating the normal pressure environment of the working environment and reducing the influence of the corrosion rate caused by the gas pressure.

[0043] The reaction chamber 8 is detachably built into the heating chamber 3 , and the reaction chamber 8 can be conveniently taken out by opening the furnace cover 5 ; a handle 1 is provided on the furnace cover 5 to facilitate opening and closing of the furnace cover 5 .

[0044] A heating wire 2 and a heating chamber thermocouple 9 are provided in the heating chamber 3. The heating wire 2 provides heat to the heating chamber 3. The working temperature in the reaction chamber is monitored by the heating chamber thermocouple 9 to provide an accurate working temperature for simulating the corrosive medium in the reaction chamber.

[0045] As a preferred embodiment, the heating wire 2 can at least surround the outer wall of the cavity of the reaction chamber 8 to make the interior of the cavity of the reaction chamber 8 heated evenly.

[0046] As a preferred embodiment, a reaction chamber thermocouple 6 is provided inside the cavity of the reaction chamber 8, which can more accurately monitor the working temperature inside the reaction chamber and provide a precise working temperature for simulating the corrosive medium inside the reaction chamber.

[0047] In this embodiment, the simulated corrosion device adopted monitors and adjusts the heating power in real time through the built-in temperature control instrument. When performing simulated corrosion, by setting parameters such as the heating rate, heat preservation time, and temperature range, the heating program of the device is set, and finally the program is saved and started to run to achieve the preset temperature rise amplitude and holding time.

[0048] When performing simulated corrosion, first weigh 800 g of ammonium fluoride solid, then fill the ammonium fluoride solid into the reaction chamber 8, bury the specimen in the ammonium fluoride solid, and when burying the specimen, keep the distance between the specimen and the bottom of the reaction chamber 8 greater than 2 cm, and the buried depth greater than 2 cm. Set the simulated corrosion device to program heating: heat from room temperature to 230 °C in 70 minutes, keep warm for 6 hours, and then cool naturally. At this time, the ammonium fluoride solid is consumed, take out the specimen, add ammonium fluoride solid again, and repeat 4 times to complete the simulated corrosion experiment.

[0049] (3) Calculation of corrosion rate: After the simulated corrosion test is completed, brush the specimen clean with a brush, rinse it with distilled water, wipe it with filter paper and dry it, place it on a clean filter paper, place it in a desiccator for more than 4 h, weigh it and record it as M 1 (accurate to 0.0001 g).

[0050] Calculate the corrosion rate: The corrosion rate calculation formula is C 1 =8000*(M 0 -M 1 ) / (ρ*A*t), and the results are shown in Table 1.

[0051] Among them, C 1 is the corrosion rate, mm / a; M 0 is the mass of the sample before corrosion, g; M 1 is the mass of the sample after corrosion, g; ρ is the density of the corroded sample, g / mm 3 ; A is the area of the sample exposed to the corrosive environment, mm 2 ; t is the corrosion test time, h; 8000 is equivalent to the number of hours in a year.

[0052] Refer to Figure 1 , which is the SEM image of Monel-400 after simulated corrosion in this embodiment. The surface of the Monel-400 material is severely corroded.

[0053] Example 2

[0054] In this example, the corrosion of 310S in ammonium fluoroferrate at 800 °C was simulated and its corrosion rate was calculated, including:

[0055] (1) Prepare the specimen: Process 310S into a sample with dimensions of 50 mm × 25 mm × 5 mm, polish it successively with 400#, 800#, 1200# sandpaper and metallographic sandpaper, then clean and decontaminate it with pure water and anhydrous ethanol. After drying, weigh the sample with an electronic balance for standby, and record its initial weight as M 0 (g).

[0056] (2) Corrosion test: In this example, the simulated corrosion process was carried out in a simulated corrosion device, and the simulated corrosion device used in this example was the same as that in Example 1.

[0057] Weigh 1000 g of ammonium fluoroferrate solid, then fill the ammonium fluoroferrate solid into the reaction chamber 8, bury the specimen in the ammonium fluoroferrate solid. When burying the specimen, keep the distance between the specimen and the bottom of the reaction chamber 8 greater than 2 cm, and the buried depth greater than 2 cm. Set the simulated corrosion device for programmed heating: heat from room temperature to 800 °C in 230 minutes, keep it warm for 5 hours, and then cool it naturally. At this time, the ammonium fluoroferrate solid is consumed. Take out the specimen, add ammonium fluoroferrate again, and repeat 8 times to complete the simulated corrosion experiment.

[0058] (3) Corrosion rate calculation: After the simulated corrosion test, brush the test piece clean with a brush, first rinse it with distilled water, wipe it with filter paper and dry it, place it on a clean filter paper, place it in a dryer for more than 4 h, weigh it and record it as M 1 (accurate to 0.0001 g).

[0059] Refer to Figure 3 , which is the electron microscope image of 310S after simulated corrosion in this example. The surface of 310S is severely corroded.

[0060] Calculate the corrosion rate using the calculation formula in Example 1, and the results are shown in Table 1.

[0061] Example 3

[0062] In this example, the corrosion of Inconel625 in ammonium fluorosilicate and ammonium bifluoride at 350 °C was simulated and its corrosion rate was calculated, including:

[0063] (1) Prepare the specimen: Process Inconel625 into a block with dimensions of 50 mm × 20 mm × 2 mm, polish it successively with 400#, 800#, 1200# sandpaper and metallographic sandpaper, then clean and decontaminate it with pure water and anhydrous ethanol. After drying, weigh the sample with an electronic balance for standby, and record its initial weight as M 0 (g).

[0064] (2) Corrosion test: In this embodiment, the simulated corrosion process is carried out in a simulated corrosion device, and the simulated corrosion device used in this embodiment is the same as that in Embodiment 1.

[0065] Weigh 500 g of ammonium bifluoride and ammonium fluorosilicate solids respectively, then fill the ammonium fluorosilicate and ammonium bifluoride solids into the reaction chamber, bury the sample in the ammonium fluorosilicate and ammonium bifluoride solids, and keep the distance between the sample and the bottom of the reaction chamber 8 greater than 2 cm and the buried depth greater than 2 cm when burying the sample. Set the simulated corrosion device to program heating: heat from room temperature to 350 °C in 180 minutes, keep warm for 10 hours, and then cool naturally. At this time, the ammonium fluorosilicate and ammonium bifluoride are consumed. Take out the sample, add ammonium fluorosilicate and ammonium bifluoride again, and repeat the test 10 times to complete the simulated corrosion experiment.

[0066] (3) Corrosion rate calculation: After the simulated corrosion test is completed, brush the sample clean with a brush, rinse it with distilled water, wipe it with filter paper and dry it, place it on a clean filter paper, place it in a dryer for more than 4 h, weigh it and record it as M 1 (accurate to 0.0001 g).

[0067] Refer to Figure 4 , which is the SEM image of Inconel625 after simulated corrosion in this embodiment.

[0068] Calculate the corrosion rate using the calculation formula in Embodiment 1, and the results are shown in Table 1.

[0069] Data characterization

[0070] Refer to Table 1, which is the corrosion rate of the specimens calculated in Embodiments 1-3 of this application.

[0071] Table 1 Corrosion rate of specimens calculated in Embodiments 1-3

[0072] Example Average corrosion rate (mm / a) 1 0.859 2 67.101 3 0.196

[0073] As can be seen from the above embodiments, by adopting the technical solution of this application, the corrosion situation of metal materials under fluorine-containing media and high-temperature conditions can be simulated quickly. For the corrosion situation of metal materials in a strongly corrosive environment that cannot be detected, especially in an environment that requires continuous operation, it cannot be directly obtained. The corrosion situation can be accurately estimated through the above experimental method, so as to replace the metal materials before accidents or losses occur, which can not only avoid waste of materials, but also ensure production safety.

[0074] Aspects, embodiments, features, and examples of the present invention should be considered illustrative in all respects and not intended to limit the present invention, the scope of which is defined only by the claims. Other embodiments, modifications, and uses will be apparent to those skilled in the art without departing from the spirit and scope of the claimed invention.

Claims

1. A method for simulating and calculating the corrosion rate of metal materials in fluorine-containing solid media, characterized in that: include: Weigh the metal material to be tested, calculate the surface area of ​​the metal material to be tested, then bury the metal material to be tested in a fluorine-containing solid medium, heat and keep warm to simulate corrosion, weigh the metal material to be tested after natural cooling, and calculate the corrosion rate of the metal material to be tested; The calculation formula is: C1 = 8000*(M0-M1) / (ρ*A*t), where C1 is the corrosion rate, in units of mm / a; M0 is the mass of the metal material to be tested before corrosion, in units of g; M1 is the mass of the metal material to be tested after corrosion, in units of g; ρ is the density of the metal material to be tested, in g / mm 3 ; A is the surface area of ​​the metal material to be tested, unit: mm 2 ; t is the simulated corrosion time, in h.

2. The method for simulating and calculating the corrosion rate of metal materials in fluorine-containing solid media according to claim 1, characterized in that: The steps include: S1. Remove the surface oxide layer and impurities of the metal material to be tested, weigh it after drying, and calculate the surface area of ​​the metal material to be tested; S2. Filling the fluorine-containing solid medium in a simulated corrosion device, and then burying the metal material to be tested in the fluorine-containing solid medium, heating and then keeping warm, and completing the simulated corrosion after natural cooling; S3. The metal material to be tested after the simulated corrosion is cleaned, dried and weighed; S4. Calculate the corrosion rate of the metal material to be tested according to the calculation formula.

3. The method for simulating and calculating the corrosion rate of metal materials in fluorine-containing solid media according to claim 2, characterized in that: The fluorine-containing solid medium includes any one of non-metallic fluorides and metal fluorides or a combination of the two.

4. The method for simulating and calculating the corrosion rate of metal materials in fluorine-containing solid media according to claim 3, characterized in that: The non-metallic fluoride includes any one or more combinations of ammonium fluoride and ammonium bifluoride.

5. The method for simulating and calculating the corrosion rate of metal materials in fluorine-containing solid media according to claim 3, characterized in that: The metal fluoride includes any one or more combinations of ammonium fluoroferrate, ammonium fluorosilicate, magnesium fluoride and calcium fluoride.

6. The method for simulating and calculating the corrosion rate of metal materials in fluorine-containing solid media according to claim 2, characterized in that: The metal material to be tested is buried in the fluorine-containing solid medium, with the distance to the surface of the fluorine-containing solid medium being greater than 2 cm.

7. The method for simulating and calculating the corrosion rate of metal materials in fluorine-containing solid media according to claim 2, characterized in that include: In S2, the metal material to be tested is buried in the fluorine-containing solid medium, heated to 230°C-800°C and kept warm for 5h-10h until the fluorine-containing solid medium is consumed, the metal material to be tested is taken out, and the fluorine-containing solid medium is added again to heat and keep warm, and this is repeated 4-10 times. After natural cooling, the simulated corrosion is completed.

8. The method for simulating and calculating the corrosion rate of metal materials in fluorine-containing solid media according to claim 2, characterized in that: S1 also includes processing the metal material to be tested into a block sample and polishing and cleaning the surface to remove the surface oxide layer and impurities.

9. A device for simulating and calculating the corrosion rate of metal materials in fluorine-containing solid media, characterized in that: At least: A reaction chamber for accommodating a fluorine-containing solid medium; as well as A heating device for heating the reaction chamber; A heat preservation device for maintaining a constant temperature of the reaction chamber; When performing simulation, the fluorine-containing solid medium is filled in the reaction chamber, and then the metal material to be tested is buried in the fluorine-containing solid medium. The reaction chamber is heated by the heating device and kept warm by the heat preservation device.

10. The device for simulating and calculating the corrosion rate of metal materials in fluorine-containing solid media according to claim 9, characterized in that: The heat-insulating device is a heat-insulating layer, which is arranged on the outer wall of the reaction chamber; a cavity structure is formed between the heat-insulating layer and the reaction chamber, and the cavity structure forms a heating chamber; the heating device is built into the heating chamber; preferably, the heating device is a heating wire, which is evenly distributed on the outer wall of the reaction chamber.

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