Accelerated test method for corrosion process and performance of metal test piece based on corrosion and rust prevention
By applying axial tensile stress to martensitic steel specimens and corroding them in a neutral salt spray environment, combined with morphology analysis and mechanical testing, the problem of performance changes of martensitic steel during corrosion and anti-rust oil aging was solved, and the testing efficiency of corrosion resistance and mechanical properties was improved.
Patent Information
- Application Number
- CN202510700772.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-28
- Publication Date
- 2025-09-05
AI Technical Summary
In the existing technology, martensitic steel is prone to forming pits under the action of corrosion, resulting in structural stress concentration and reduced bearing capacity. In addition, rust-proof oil oxidizes and deteriorates during long-term storage, causing its rust-proof ability to lose effectiveness. There is a lack of effective accelerated test methods to analyze changes in its mechanical properties.
An accelerated corrosion test method was designed to evaluate the effect of anti-rust oil aging on martensitic steel by applying axial tensile stress to metal specimens and corroding them in a neutral salt spray environment. The method was combined with macroscopic microstructure analysis and mechanical property testing.
It has achieved the purpose of revealing the performance change law of martensitic steel during corrosion and anti-rust process in a short time, improving the corrosion resistance of martensitic steel, and accurately testing the influence of different conditions on its mechanical properties.
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Figure CN120594375A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of metal material corrosion and protection and mechanical property testing, and particularly relates to an accelerated test method for the corrosion process and performance of metal specimens based on rust and rust prevention. Background Art
[0002] Martensitic steel has excellent comprehensive properties such as strength, toughness, high hardness, wear resistance, and hot working processability. It is widely used in the manufacture of important components subjected to high stress in the fields of aerospace, petrochemicals, energy and power, marine engineering, etc., and plays an important role in structural lightweighting. However, under the action of corrosion, steel components will form pits on the surface and suffer quality loss, causing stress concentration, increased local stress, and reduced bearing capacity of the components, and may lead to sudden destruction of the structure. Therefore, the corrosion problem of steel structures has gradually attracted people's attention. Using rust-proof oil for protection is an economical and efficient method among temporary rust prevention methods. However, during the long-term storage process of rust-proof oil in actual application, it will undergo oxidative deterioration and volatilization of effective ingredients, resulting in the loss of rust prevention ability. Therefore, we urgently need to develop an accelerated test method for the failure behavior of rust-proof oil during storage through physical volatilization and chemical deterioration. Summary of the Invention
[0003] The purpose of the present invention is to address the above shortcomings and propose a microstructure and mechanical property testing method for martensitic steel components after corrosion and under temporary rust-proof oil protection, so as to analyze the mechanical property stability of martensitic steel with poor corrosion resistance.
[0004] The present invention relates to a method for accelerating the corrosion process and performance testing of a metal specimen based on rust and rust prevention, which specifically comprises the following steps: S1. Obtain new anti-rust oil and aged anti-rust oil, and divide metal test pieces into groups, applying unaged anti-rust oil to one group and applying aged anti-rust oil to the other group; S2. Apply axial tensile stresses of 0 MPa, 346 MPa, and 693 MPa to the metal test pieces treated in step S1, respectively, and place the metal test pieces after the tensile stresses are applied in a neutral salt spray corrosion environment for an accelerated salt spray corrosion test; S3. Perform macroscopic morphology analysis and corrosion rate calculation on the metal test piece processed in step S2.
[0005] S4. Perform mechanical property testing on the metal test piece processed in step S2.
[0006] The step of obtaining the aged anti-rust oil in step S1 comprises: The new rust-proof oil is subjected to accelerated aging by physical volatilization and chemical deterioration, causing the composition and proportion of the rust-proof oil to change, thereby obtaining aged rust-proof oil. The aged rust-proof oil is sprayed on the surface of a metal test piece and purged with nitrogen. The salt spray corrosion test of the rust-proof oil-metal test piece under atmospheric contact is then carried out.
[0007] Furthermore, step S2 further includes the following steps: S2.1. Construct an accelerated corrosion test device for metal specimens based on the coupling effect of salt spray corrosion environment and axial tensile stress, including base parts (4), (8) and (10) and other connecting structures; S2.2. Attach the strain gauge (7) to the geometric center of the specimen (6) using organic glue. S2.3. Place the specimen (6) with the strain gauge (7) attached between the upper groove threaded rod stress loading fixture (5) and the lower groove fixed fixture (9). The threaded rod adopts a micrometer screw. A stop knob (3) is set on the outside of the box. The adjustment part can be provided with a coarse adjustment knob (2) and a fine adjustment knob (1). A movable scale and a fixed scale can be set in front of the coarse adjustment knob.
[0008] S2.4. Connect the strain gauge (7) to the strain meter (11), reset the strain meter (11) reading to zero, and then turn the coarse adjustment knob first, and then turn the fine adjustment knob to gradually apply axial tensile stress to the specimen (6). At this time, the strain gauge (11) displays the current strain value on the specimen (6). When the strain value reading is equal to the target strain value, turn the stop knob to lock the state.
[0009] S2.5. Calculate the tensile stress on specimen (6); S2.6. Place multiple specimens with set stresses in a corrosive environment and conduct stress-accelerated corrosion testing.
[0010] Furthermore, step S2 further includes: The metal specimens after tensile stress were placed in a neutral salt spray corrosion environment for salt spray corrosion test. A neutral salt spray corrosion environment was configured, with NaCl solution as the corrosion medium and 6.0wt% NaCl solution as the spray medium. The pH value should be adjusted between 6.5 and 7.2 at 23℃ to 27℃. The pH value was measured with a potentiometric pH meter using an electrode suitable for weakly buffered NaCl solution. The pH value of the solution was adjusted with a solution prepared with analytically pure hydrochloric acid, sodium hydroxide or sodium bicarbonate. The salt spray test was conducted with corrosion cycles of 24h, 48h, 96h and 168h.
[0011] Furthermore, the method for performing macroscopic structural morphology analysis on the metal specimen in step S3 includes the following steps: The method for macroscopic morphology analysis of metal specimens is to use Image-Pro Plus software to count the percentage of surface rust area of salt spray test specimens, and to compare and analyze the effects of different surface treatment conditions and different salt spray concentrations on the corrosion resistance of martensitic steel.
[0012] Furthermore, the method for calculating the corrosion rate of the metal test piece after the corrosion resistance test in step S3 includes the following steps: S3.1. Use 500 ml of HCl, 500 ml of H2O, and 6 g of hexamethylenetetramine as a rust removal solution for the rust layer on the surface of the test piece. After rust removal, dry the test piece and weigh it. S3.2. Calculate the salt spray corrosion rate of martensitic steel by calculating the weight loss per unit time and per unit area. The calculation expression for the corrosion weight loss per unit surface area is: in, is the corrosion weight loss per unit surface area, is the weight of the specimen before corrosion, Corrosion of test piece The weight after rust removal, is the area of the specimen corrosion; S3.3. Calculate the salt spray corrosion rate of martensitic steel using the following expression: in, is the corrosion rate.
[0013] Furthermore, the method for performing mechanical property testing on the metal test piece in step S4 includes the following steps: S4.1. Prepare tensile test pieces from metal test pieces by wire cutting; S4.2. Perform a tensile test on the tensile test specimen obtained in step S4.1 using an electronic universal testing machine, setting the tensile rate to 1 mm / min. After the tensile test, plot a tensile curve using the test data and determine the yield strength and tensile strength of the specimen at different corrosion cycles. A yield strength ratio graph is also plotted, assuming the yield strength ratio of the freshly oiled metal specimen after 24 hours of accelerated corrosion is 100%.
[0014] The beneficial effects of the present invention are: The present invention discloses a method for accelerating the corrosion process and performance testing of metal specimens based on corrosion and rust prevention process analysis. This method is used to analyze the changes in the mechanical properties of martensitic steel components after corrosion and when temporarily protected with rust preventative oil. This method can quickly reveal the behavior and performance changes of martensitic steel during corrosion and rust prevention processes. Furthermore, the application of rust preventative oil can improve the corrosion resistance of martensitic steel.
[0015] The present invention discloses a method for accelerating the corrosion process and performance testing of metal specimens based on rust and rust prevention, which can accurately test the influence of different acceleration conditions on the mechanical properties of martensitic steel, thereby analyzing the mechanical property stability of martensitic steel with poor corrosion resistance and its components. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 It is a flowchart of the present invention; Figure 2 This is a diagram of the accelerated corrosion test device for metal specimens based on the coupling effect of salt spray corrosion environment and axial tensile stress; Figure 3 The percentage of rusted area of metal specimens coated with new anti-rust oil, aged anti-rust oil and no anti-rust oil as the salt spray corrosion time increases; Figure 4 Apply different stress levels to metal specimens to determine the change in corrosion rate; Figure 5 This is a graph showing the yield strength ratio of metal specimens coated with new anti-rust oil, aged anti-rust oil, and no anti-rust oil over salt spray corrosion time. DETAILED DESCRIPTION
[0017] In order to make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present invention and are not intended to limit the present invention. That is, the specific embodiments described herein are only some embodiments of the present invention, not all embodiments. Generally, the components of the specific embodiments of the present invention described and illustrated in the drawings herein can be arranged and designed in various different configurations, and the present invention can also have other embodiments.
[0018] Therefore, the following detailed description of the specific embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but is merely representative of selected specific embodiments of the present invention. All other specific embodiments obtained by those skilled in the art based on the specific embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.
[0019] In order to further understand the content, features and effects of the present invention, the following specific embodiments are given with reference to the accompanying drawings. Figure 1-Figure 5 The detailed instructions are as follows: Specific implementation method one: A method for testing the accelerated corrosion process and performance of metal specimens based on rust and rust prevention, comprising the following steps: S1. Obtain new anti-rust oil and aged anti-rust oil, and divide metal test pieces into groups, applying unaged anti-rust oil to one group and applying aged anti-rust oil to the other group; S2. Apply axial tensile stresses of 0 MPa, 346 MPa, and 693 MPa to the metal test pieces treated in step S1, respectively, and place the metal test pieces after the tensile stresses are applied in a neutral salt spray corrosion environment for an accelerated salt spray corrosion test; S3. Perform macroscopic morphology analysis and corrosion rate calculation on the metal test piece processed in step S2.
[0020] S4. Perform mechanical property testing on the metal test piece processed in step S2.
[0021] The step of obtaining the aged anti-rust oil in step S1 comprises: The new rust-proof oil is subjected to accelerated aging by physical volatilization and chemical deterioration, causing the composition and proportion of the rust-proof oil to change, thereby obtaining aged rust-proof oil. The aged rust-proof oil is sprayed on the surface of a metal test piece and purged with nitrogen. The salt spray corrosion test of the rust-proof oil-metal test piece under atmospheric contact is then carried out.
[0022] Furthermore, step S2 further includes the following steps: S2.1. Construct an accelerated corrosion test device for metal specimens based on the coupling effect of salt spray corrosion environment and axial tensile stress, including base parts (4), (8) and (10) and other connecting structures; S2.2. Attach the strain gauge (7) to the geometric center of the specimen (6) using organic glue. S2.3. Place the specimen (6) with the strain gauge (7) attached between the upper groove threaded rod stress loading fixture (5) and the lower groove fixed fixture (9). The threaded rod adopts a micrometer screw. A stop knob (3) is set on the outside of the box. The adjustment part can be provided with a coarse adjustment knob (2) and a fine adjustment knob (1). A movable scale and a fixed scale can be set in front of the coarse adjustment knob.
[0023] S2.4. Connect the strain gauge (7) to the strain meter (11), reset the strain meter (11) reading to zero, and then turn the coarse adjustment knob first, and then turn the fine adjustment knob to gradually apply axial tensile stress to the specimen (6). At this time, the strain gauge (11) displays the current strain value on the specimen (6). When the strain value reading is equal to the target strain value, turn the stop knob to lock the state.
[0024] S2.5. Calculate the tensile stress on specimen (6); S2.6. Place multiple specimens with set stresses in a corrosive environment and conduct stress-accelerated corrosion testing.
[0025] Furthermore, step S2 further includes: The metal specimens after tensile stress were placed in a neutral salt spray corrosion environment for salt spray corrosion test. A neutral salt spray corrosion environment was configured, with NaCl solution as the corrosion medium and 6.0wt% NaCl solution as the spray medium. The pH value should be adjusted between 6.5 and 7.2 at 23℃ to 27℃. The pH value was measured with a potentiometric pH meter using an electrode suitable for weakly buffered NaCl solution. The pH value of the solution was adjusted with a solution prepared with analytically pure hydrochloric acid, sodium hydroxide or sodium bicarbonate. The salt spray test was conducted with corrosion cycles of 24h, 48h, 96h and 168h.
[0026] Furthermore, the method for performing macroscopic structural morphology analysis on the metal specimen in step S3 includes the following steps: The method for macroscopic morphology analysis of metal specimens is to use Image-Pro Plus software to count the percentage of surface rust area of salt spray test specimens, and to compare and analyze the effects of different surface treatment conditions and different salt spray concentrations on the corrosion resistance of martensitic steel.
[0027] Furthermore, the method for calculating the corrosion rate of the metal test piece after the corrosion resistance test in step S3 includes the following steps: S3.1. Use 500 ml of HCl, 500 ml of H2O, and 6 g of hexamethylenetetramine as a rust removal solution for the rust layer on the surface of the test piece. After rust removal, dry the test piece and weigh it. S3.2. Calculate the salt spray corrosion rate of martensitic steel by calculating the weight loss per unit time and per unit area. The calculation expression for the corrosion weight loss per unit surface area is: in, is the corrosion weight loss per unit surface area, is the weight of the specimen before corrosion, Corrosion of test piece The weight after rust removal, is the corroded area of the specimen; S3.3. Calculate the salt spray corrosion rate of martensitic steel using the following expression: in, is the corrosion rate.
[0028] Furthermore, the method for performing mechanical property testing on the metal test piece in step S4 includes the following steps: S4.1. Prepare tensile test pieces from metal test pieces by wire cutting; S4.2. Perform a tensile test on the tensile test specimen obtained in step S4.1 using an electronic universal testing machine, setting the tensile rate to 1 mm / min. After the tensile test, plot a tensile curve using the test data and determine the yield strength and tensile strength of the specimen at different corrosion cycles. A yield strength ratio graph is also plotted, assuming the yield strength ratio of the freshly oiled metal specimen after 24 hours of accelerated corrosion is 100%.
[0029] The corrosion process of martensitic steel is affected by various factors, such as the steel's microstructure, corrosion product morphology, and the external corrosion environment. The present invention can accurately test the effects of different acceleration conditions on the mechanical properties of martensitic steel, thereby analyzing the mechanical stability of martensitic steel and its components with poor corrosion resistance.
[0030] It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.
[0031] Although the present application has been described above with reference to specific embodiments, various modifications may be made thereto and components may be substituted with equivalents without departing from the scope of the present application. In particular, as long as there are no structural conflicts, the various features of the embodiments disclosed herein may be combined with each other in any manner, and the omission of an exhaustive description of these combinations in this specification is solely for the sake of space and resource conservation. Therefore, the present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions within the scope of the claims.
Claims
1. An accelerated test method for the corrosion process and performance of metal specimens based on rust and rust prevention, characterized in that: The steps include: S1. Obtain new anti-rust oil and aged anti-rust oil, and divide metal test pieces into groups, applying unaged anti-rust oil to one group and applying aged anti-rust oil to the other group; S2. Apply axial tensile stresses of 0 MPa, 346 MPa, and 693 MPa to the metal test pieces treated in step S1, respectively, and place the metal test pieces after the tensile stresses are applied in a neutral salt spray corrosion environment for an accelerated salt spray corrosion test; S3, performing macroscopic structural morphology analysis and corrosion rate calculation on the metal specimen processed in step S2; S4. Perform mechanical property testing on the metal test piece processed in step S2.
2. The method for accelerating the corrosion process and performance testing of metal specimens based on rust and rust prevention according to claim 1, characterized in that: Applying axial tensile stress to the metal test piece in step S2 further includes the following steps: S2.
1. Construct an accelerated corrosion testing device for metal specimens based on the coupling of a salt spray corrosion environment and axial tensile stress. S2.
2. Attach the strain gauge (7) to the geometric center of the specimen (6) using organic glue. S2.
3. Place the specimen (6) with the strain gauge (7) attached between the upper groove threaded rod stress loading fixture (5) and the lower groove fixed fixture (9). The threaded rod adopts a micrometer screw. A stop knob (3) is provided on the outside of the box. The adjustment part can be provided with a coarse adjustment knob (2) and a fine adjustment knob (1). A movable scale and a fixed scale can be provided in front of the coarse adjustment knob. S2.
4. Connect the strain gauge (7) to the strain meter (11), reset the strain meter (11) reading to zero, and then turn the coarse adjustment knob first, and then turn the fine adjustment knob to gradually apply axial tensile stress to the specimen (6). At this time, the strain gauge (11) displays the current strain value on the specimen (6). When the strain value reading is equal to the target strain value, turn the stop knob to lock the state; S2.
5. Calculate the tensile stress on specimen (6); S2.
6. Place multiple specimens with set stresses in a corrosive environment and conduct stress-accelerated corrosion testing.
3. The method for accelerating the corrosion process and performance testing of metal specimens based on rust and rust prevention according to claim 1, characterized in that: The salt spray corrosion test of the metal specimen in step S2 also includes: configuring a neutral salt spray corrosion environment, using NaCl solution as the corrosion medium, using a NaCl solution with a concentration of 6.0wt% as the spray medium, adjusting the pH value between 6.5 and 7.2, 23°C to 27°C, measuring the pH value with a potentiometric pH meter, using an electrode suitable for weakly buffered NaCl solution, adjusting the pH value of the solution with a solution prepared with analytical pure hydrochloric acid, sodium hydroxide or sodium bicarbonate, and conducting salt spray tests with corrosion cycles of 24h, 48h, 96h, and 168h.
4. The method for accelerating the corrosion process and performance testing of metal specimens based on rust and rust prevention according to claim 1, characterized in that: The step S3 further comprises: The method for macroscopic morphology analysis of metal specimens is to use Image-Pro Plus software to count the percentage of surface rust area of salt spray test specimens, and to compare and analyze the effects of different surface treatment conditions and different salt spray concentrations on the corrosion resistance of martensitic steel.
5. The method for accelerating the corrosion process and performance testing of metal specimens based on rust and rust prevention according to claim 1, characterized in that: The step S3 further comprises: S3.
1. Use 500 ml of HCl, 500 ml of H2O, and 6 g of hexamethylenetetramine as a rust removal solution for the rust layer on the surface of the test piece. After rust removal, dry the test piece and weigh it. S3.
2. Calculate the salt spray corrosion rate of martensitic steel by calculating the weight loss per unit time and per unit area. The calculation expression for the corrosion weight loss per unit surface area is: in, is the corrosion weight loss per unit surface area, is the weight of the specimen before corrosion, Corrosion of test piece t The weight after rust removal, is the corroded area of the specimen; S3.
3. Calculate the salt spray corrosion rate of martensitic steel using the following expression: in, is the corrosion rate.
6. The method for testing the mechanical properties of metal specimens based on corrosion and anti-rust process analysis according to claim 1, characterized in that: The step S4 further includes: S4.
1. Prepare tensile test pieces from metal test pieces by wire cutting; S4.
2. Perform a tensile test on the tensile test piece obtained in step S4.1 using an electronic universal testing machine. Set the tensile rate to 1 mm / min. After the tensile test, draw a tensile curve using the test data, and obtain the yield strength and tensile strength of the test piece at different corrosion cycles. Draw a yield strength ratio graph, and stipulate that the yield strength ratio of the newly oiled metal test piece with an accelerated corrosion time of 24 hours is 100%.