A method for predicting the hydrogen corrosion resistance of stainless steel based on hydrogen corrosion growth factor

Abstract

The present invention provides a method for predicting the hydrogen corrosion resistance of a stainless steel material based on a hydrogen corrosion growth factor, comprising the following steps: step 1: cutting the stainless steel material into thin slice samples by wire cutting, polishing the sample surfaces to a mirror surface with grinder sandpaper, washing with water, wiping with ethanol, drying with cold air, and finally placing in a dryer for standby use; step 2: nickel-plating the sample on one side, where the nickel-plated surface is the non-hydrogen-charged surface; after the nickel plating is completed, rinsing the thin slice sample with distilled water and alcohol in turn for standby use; application of the technical solution can quickly predict the hydrogen corrosion resistance of the stainless steel material, greatly shortening the test cycle and intuitively expressing the corrosion resistance of the material, which is an effective improvement and perfection of the electrochemical method.

Description

Technical Field

[0001] The invention relates to the technical field of corrosion resistance detection of stainless steel materials, in particular to a method for predicting the hydrogen corrosion resistance of stainless steel materials based on hydrogen corrosion growth factors. Background Art

[0002] Hydrogen energy, with its widespread availability, cleanliness, environmental friendliness, and renewable nature, is the most promising pollution-free energy source and a promising future strategic resource to replace fossil fuels. It is crucial for addressing energy and pollution challenges encountered in human development. However, hydrogen is a highly reactive element, and materials are susceptible to hydrogen-induced cracking in hydrogen environments. Therefore, it is necessary to conduct experimental evaluation and research on the performance of materials in hydrogen environments.

[0003] Currently, the main methods for testing stainless steel's resistance to hydrogen-induced cracking and hydrogen corrosion are slow strain rate tensile testing and electrochemical testing. The slow strain rate tensile testing method requires the use of high-pressure hydrogen, which not only places high demands on equipment but also results in long testing cycles, high labor and material resources, and high testing costs. While electrochemical testing can accelerate the corrosion testing process, the hydrogen diffusion coefficient commonly used in this method still needs to be determined based on a large number of slow strain rate tests, and the calculation of this coefficient is complex and not intuitive. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a method for predicting the hydrogen corrosion resistance of stainless steel materials based on hydrogen corrosion growth factor, which can quickly predict the hydrogen corrosion resistance of stainless steel materials, greatly shorten the test cycle, and intuitively express the corrosion resistance of the material, which is an effective improvement and perfection of the electrochemical method.

[0005] To achieve the above object, the present invention adopts the following technical solution: a method for predicting the hydrogen corrosion resistance of stainless steel materials based on hydrogen corrosion growth factor, comprising the following steps:

[0006] Step 1: Cut the stainless steel material into 30mm×30mm×0.5mm thin slices by wire cutting. The surface of the sample is polished to a mirror finish using 320-mesh, 600-mesh, and 1200-mesh sandpaper on a grinder. Wash it with water, wipe it with ethanol, dry it with cold air, and finally place it in a desiccator for later use.

[0007] Step 2: Nickel-plating is performed on one side of the specimen, with the nickel-plated side being the non-hydrogen-charged side. During nickel plating, the specimen serves as the cathode and the nickel foam is the anode. The auxiliary electrode clip and reference electrode clip of the electrode cable of the main unit of the CH I660D dual-unit electrochemical workstation are clamped on the nickel foam, and the working electrode clip is clamped on the specimen. The electroplating temperature is 25°C, the current density is 5 mA / cm2, and the nickel plating time is 12 minutes. After nickel plating, the thin slice specimen is rinsed with distilled water and then ethanol for later use.

[0008] Step 3: Place the thin sheet-like test sample prepared in step 2 between the first connecting sealing ring and the second connecting sealing ring, with the nickel-coated surface of the test sample facing the anode cell. Fix the measuring device, then install the anode cell auxiliary electrode and the anode cell reference electrode in the anode cell, and connect them to the test sample and the electrochemical workstation to form an anode electrolytic cell hydrogen measurement system. At the same time, connect the anode electrolytic cell hydrogen measurement system to a computer.

[0009] Step 4: Inject 0.1 mol / L NaOH anolyte into the anode cell, adjust the reference potential of the electrochemical workstation to 300 mV, and start the entire anode electrolytic cell hydrogen measurement system;

[0010] Step 5: When the hydrogen permeation current value displayed by the computer drops below 1.0 μA, pause recording and clear the data recorded by the computer. Then, install a cathode auxiliary electrode in the cathode cell, connect the positive and negative electrodes of the DC constant current power supply to the cathode auxiliary electrode and the test sample respectively, and inject a mixed solution of 0.5 mol / L H2SO4 and 3 g / L thiourea as the cathode electrolyte into the cathode cell. Turn on the DC constant current power supply and control its output current density to 5 mA / cm2. At the same time, restart recording the test data.

[0011] Step 6: After the hydrogen permeation current data recorded by the computer in step 5 no longer increases over time and remains stable for a period of time, the hydrogen permeation experiment is terminated, the DC constant current power supply and the electrochemical workstation are turned off, and the experimental data are saved on the computer. Finally, the catholyte and anolyte in the cathode cell and the anode cell are drained respectively, and the test sample sandwiched between the two electrodes is removed. After processing the obtained data, a hydrogen permeation curve is obtained;

[0012] Step 7: Replace the sample, repeat steps 3 to 6, and change the output current density of the constant current source to obtain hydrogen diffusion curves under different hydrogen concentrations. The maximum slope of the hydrogen permeation curve is obtained to evaluate the corrosion resistance of the stainless steel material.

[0013] In a preferred embodiment, the hydrogen corrosion growth factor is obtained by the following formula (1):

[0014]

[0015] Where, δ is the elongation after fracture under a certain hydrogen concentration; δ0 is the reference value of the elongation after fracture, and the tensile fracture lengths A, B, c, and m of the material are taken as material parameters;

[0016] Φ is the hydrogen corrosion growth factor, k is the maximum value of the slope of the hydrogen diffusion curve at a certain hydrogen concentration, and k0 is the maximum value of the slope of the hydrogen diffusion curve at the critical hydrogen concentration.

[0017] Compared with existing technologies, the present invention has the following advantages: It proposes the concept of a hydrogen corrosion growth factor and an evaluation method based on this factor. This method establishes the relationship between elongation and the hydrogen corrosion growth factor based on electrochemical testing and small punch fracture testing, enabling rapid prediction of the hydrogen corrosion resistance of stainless steel materials. Compared with conventional methods, this method significantly shortens the testing cycle while providing a visual representation of the material's corrosion resistance, effectively enhancing and improving electrochemical methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of the k value of a hydrogen permeation curve is shown in the preferred embodiment of the present invention;

[0019] Figure 2 Schematic diagram of the relationship between hydrogen corrosion growth factor and elongation after fracture of a material in a preferred embodiment of the present invention;

[0020] Figure 3 This is a hydrogen permeation test diagram of a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0023] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application; as used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form, and it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or their combinations.

[0024] refer to Figures 1 to 2 The hydrogen corrosion growth factor k proposed in the present invention has a clear physical meaning. The larger k is, the higher the capture efficiency of hydrogen in steel and the higher the hydrogen content in stainless steel. Therefore, the hydrogen corrosion growth factor reflects the capture efficiency of hydrogen in steel and is an important factor affecting the hydrogen embrittlement sensitivity of the material.

[0025] Step 1: Cut the stainless steel material into 30mm×30mm×0.5mm slices by wire cutting. The sample surface is polished to a mirror finish using 320-mesh, 600-mesh, and 1200-mesh sandpaper on a grinder. Wash it with water, wipe it with ethanol, dry it with cold air, and finally place it in a desiccator for later use.

[0026] Step 2: Nickel-plating is performed on one side of the specimen. The nickel-plated surface is the non-hydrogen-charged surface. During nickel plating, the specimen is the cathode and the anode is the nickel foam. The auxiliary electrode clamp and the reference electrode clamp of the electrode cable of the main unit of the CHI660D dual-unit electrochemical workstation are clamped on the nickel foam, and the working electrode clamp is clamped on the specimen. The electroplating temperature is 25°C, the current density is 5mA / cm2, and the nickel plating time is 12min. After the nickel plating is completed, the specimen is rinsed with distilled water and then alcohol for later use;

[0027] Step 3: Place the thin sheet-like test sample prepared in step 2 between the first connecting sealing ring and the second connecting sealing ring, with the nickel-coated surface of the test sample facing the anode cell. While ensuring a good seal and no leakage, fix the measuring device, then install the anode cell auxiliary electrode and the anode cell reference electrode in the anode cell, and connect them to the test sample and the electrochemical workstation to form an anode electrolytic cell hydrogen measurement system. At the same time, connect the anode electrolytic cell hydrogen measurement system to a computer.

[0028] Step 4: Inject 0.1 mol / L NaOH anolyte into the anode cell, adjust the reference potential of the electrochemical workstation to 300 mV, and start the entire anode electrolytic cell hydrogen measurement system;

[0029] Step 5: When the hydrogen permeation current value displayed by the computer drops below 1.0 μA, pause recording and clear the data recorded by the computer. Then, install a cathode auxiliary electrode in the cathode cell, connect the positive and negative electrodes of the DC constant current power supply to the cathode auxiliary electrode and the test sample respectively, and inject a mixed solution of 0.5 mol / L H2SO4 and 3 g / L thiourea as the cathode electrolyte into the cathode cell. Turn on the DC constant current power supply and control its output current density to 5 mA / cm2. At the same time, restart recording the test data.

[0030] Step 6: After the hydrogen permeation current data recorded by the computer in step 5 no longer increases over time and remains stable for a period of time, the hydrogen permeation experiment is terminated, the DC constant current power supply and the electrochemical workstation are turned off, and the experimental data are saved on the computer. Finally, the catholyte and anolyte in the cathode cell and the anode cell are drained respectively, and the test sample sandwiched between the two electrodes is removed. After processing the obtained data, a hydrogen permeation curve is obtained;

[0031] Step 7: Replace the sample, repeat steps 3 to 6, and change the output current density of the constant current source to obtain hydrogen diffusion curves under different hydrogen concentrations. The maximum slope of the hydrogen permeation curve is obtained to evaluate the corrosion resistance of the stainless steel material.

[0032] The hydrogen corrosion growth factor of the material can be obtained by the following formula (1):

[0033]

[0034] Where, δ is the elongation after fracture under a certain hydrogen concentration; δ0 is the reference value of the elongation after fracture, which can be taken as the tensile fracture length of the material; A, B, c, m are material parameters,

[0035] Φ is the hydrogen corrosion growth factor, k is the maximum value of the slope of the hydrogen diffusion curve at a certain hydrogen concentration, and k0 is the maximum value of the slope of the hydrogen diffusion curve at the critical hydrogen concentration.

[0036] Formula (1) can express the relationship between the elongation after fracture and the corrosion growth factor under various hydrogen corrosion conditions. For example, for 316L stainless steel, the relationship between the elongation after fracture and the hydrogen corrosion growth factor can be expressed as:

[0037]

[0038] refer to Figure 3 The cathode electrolytic cell hydrogen charging system includes a DC constant current power supply 1, a cathode cell 3 and a cathode cell auxiliary electrode 4. The cathode cell 3 is filled with a cathode electrolyte 5. The cathode cell auxiliary electrode 4 extends into the cathode electrolyte 5. The cathode cell auxiliary electrode 4 is connected to the positive electrode of the DC constant current power supply 1 through a wire. A cathode cell through hole 6 is opened on the side wall of the cathode cell.

[0039] The anode electrolytic cell hydrogen measurement system includes an electrochemical workstation 9, an anode cell 11, an anode cell auxiliary electrode 12 and an anode cell reference electrode 10. The anode cell 11 is filled with an anolyte 13. The anode cell auxiliary electrode 12 and the anode cell reference electrode 10 are both extended into the anolyte 11. The anode cell auxiliary electrode 12 and the anode cell reference electrode 10 are connected to the electrochemical workstation 9. An anode cell through hole is opened on the side wall of the anode cell 11, and the cathode cell through hole 6 and the anode cell through hole are arranged opposite to each other.

[0040] The test sample 8 is arranged between the cathode pool through hole 6 and the anode pool through hole 14, the surface of the test sample 8 with nickel coating faces the anode pool 13, and the surface of the test sample 8 without nickel coating faces the cathode pool 5. Rubber gaskets 7 and rubber gaskets 15 are placed between the test sample 8 and the cathode pool through hole 6 and the anode pool through hole 14. The test sample 8 is connected to the negative pole of the DC constant current power supply 1 and the electrochemical workstation 9 respectively through wires.

Claims

1. A method for predicting the hydrogen corrosion resistance of stainless steel materials based on hydrogen corrosion growth factor, characterized in that: The following steps are involved: Step 1: Cut the stainless steel material into 30mm×30mm×0.5mm thin slices by wire cutting. The surface of the sample is polished to a mirror finish using 320-mesh, 600-mesh, and 1200-mesh sandpaper on a grinder. Wash it with water, wipe it with ethanol, dry it with cold air, and finally place it in a desiccator for later use. Step 2: Nickel-plating is performed on one side of the specimen, with the nickel-plated side being the non-hydrogen-charged side. During nickel plating, the specimen serves as the cathode and the nickel foam is the anode. The auxiliary electrode clip and reference electrode clip of the electrode cable of the main unit of the CHI660D dual-unit electrochemical workstation are clamped on the nickel foam, and the working electrode clip is clamped on the specimen. The electroplating temperature is 25°C, the current density is 5 mA / cm2, and the nickel plating time is 12 minutes. After nickel plating, the thin slice specimen is rinsed with distilled water and then ethanol for later use. Step 3: Place the thin sheet-like test sample prepared in step 2 between the first connecting sealing ring and the second connecting sealing ring, with the nickel-coated surface of the test sample facing the anode cell. Fix the measuring device, then install the anode cell auxiliary electrode and the anode cell reference electrode in the anode cell, and connect them to the test sample and the electrochemical workstation to form an anode electrolytic cell hydrogen measurement system. At the same time, connect the anode electrolytic cell hydrogen measurement system to a computer. Step 4: Inject 0.1 mol / L NaOH anolyte into the anode cell, adjust the reference potential of the electrochemical workstation to 300 mV, and start the entire anode electrolytic cell hydrogen measurement system; Step 5: When the hydrogen permeation current value displayed by the computer drops below 1.0 μA, pause the recording and clear the recorded data on the computer. Then, install the cathode auxiliary electrode in the cathode cell, connect the positive and negative electrodes of the DC constant current power supply to the cathode auxiliary electrode and the test sample respectively, and inject a mixed solution of 0.5 mol / L H2SO4 and 3 g / L thiourea as the cathode electrolyte into the cathode cell. Turn on the DC constant current power supply and control its output current density to 5 mA / cm2. At the same time, restart recording the test data. Step 6: After the hydrogen permeation current data recorded by the computer in step 5 no longer increases over time and remains stable for a period of time, the hydrogen permeation experiment is terminated, the DC constant current power supply and the electrochemical workstation are turned off, and the experimental data are saved on the computer. Finally, the catholyte and anolyte in the cathode cell and the anode cell are drained respectively, and the test sample sandwiched between the two electrodes is removed. After processing the obtained data, a hydrogen permeation curve is obtained; Step 7: Replace the sample and repeat steps 3 to 6, changing the output current density of the constant current source to obtain hydrogen diffusion curves under different hydrogen concentrations. The maximum slope of the hydrogen diffusion curve is obtained to evaluate the corrosion resistance of the stainless steel material. Define Φ as the hydrogen corrosion growth factor, ; k is the maximum value of the slope of the hydrogen diffusion curve at a certain hydrogen concentration, and k0 is the maximum value of the slope of the hydrogen diffusion curve at the critical hydrogen concentration; then the elongation of the sample under the action of a certain hydrogen concentration medium has the following relationship with the hydrogen corrosion growth factor: The hydrogen corrosion growth factor is obtained by the following formula (1): Where, , δ is the elongation after fracture under a certain hydrogen concentration; δ0 is the reference value of the elongation after fracture, which is the tensile fracture length of the material; A, B, c, and m are material parameters.

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