Anti-stripping test method for low-chromium alloy centrifugal composite cast steel supporting roll

Abstract

The invention provides an anti-stripping test method for a low-chromium alloy centrifugal composite cast steel supporting roller, and relates to the technical field of anti-stripping test.The anti-stripping test method comprises the steps that test samples of different parts of the low-chromium alloy centrifugal composite cast steel supporting roller are prepared, and the test samples of the different parts are pretreated; carrying out pressure testing on the pretreated test samples at different parts, and determining corresponding ultimate pressures of the different parts; measuring the coating cohesive force of the test sample at each part of the low-chromium alloy centrifugal composite cast steel supporting roll by utilizing the corresponding ultimate pressures of different parts; the obtained ultimate pressure is increased by 5%-10%, the interface stripping condition of the coating base material is evaluated through numerical simulation, and the ultimate breaking pressure when the cohesive unit will fail is judged.

Description

Technical Field

[0001] The invention provides a method for testing the anti-stripping of a low-chromium alloy centrifugal composite cast steel support roller, and relates to the technical field of anti-stripping testing. Background Art

[0002] As cold and hot rolling mills develop towards high speed, large size and high precision, the requirements for backup rolls are also increasing. Low chromium alloy centrifugal composite cast steel backup rolls will occupy an important position in the future market with their excellent performance and manufacturing process. At the same time, with the continuous research and development and application of new materials and new processes, the performance of backup rolls will be further improved to meet higher rolling requirements.

[0003] Low chromium alloy centrifugal composite cast steel support roll is a support roll made of specific low chromium alloy material through centrifugal composite casting process. It is mainly used to support working rolls or intermediate rolls in rolling mills to prevent the working rolls from bending and deformation, thereby ensuring the output and quality of plates and strips.

[0004] The outer layer material of the low-chromium alloy centrifugal composite cast steel support roller is based on 9SiCr2MO and 75Cr3NiMo alloy cast steel materials. In the chemical composition, the C content is 0.650.9, and the Cr content is 1.503.50. These elements can significantly improve the wear resistance of the roller. The Mn content is 0.60~1.2, which helps to improve the performance of the steel and increase the strength of the steel. The Ni content is 0.20~1.0, which can improve the matrix strength and matrix hardenability, and ensure that low-hardness pearlite and ferrite do not appear in the cast structure. The Mo content is 0.300.60%, and the V content is 0.100.60%. These elements can increase the high-temperature hardness of the matrix, improve the second type of temper brittleness of the steel, and further improve the hardenability.

[0005] The anti-stripping test method is usually used to evaluate the durability and reliability of materials in specific environments, especially under high temperature, high pressure or physical impact. The anti-stripping performance of the support roller is comprehensively evaluated by combining the anti-stripping strength, spalling area, and macro and micro observation results.

[0006] However, the anti-stripping test method in the prior art does not distinguish between different parts, and the accuracy and reliability of the test are insufficient, and the true performance of each part of the support roller cannot be fully understood. In addition, the prior art cannot accurately evaluate the maximum bearing capacity of each part, which often leads to failures due to local overload in actual applications. It cannot fully reflect the tightness of the combination between the coating and the base material, which is crucial for the long-term stable operation of the support roller. It is impossible to discover potential problems and make adjustments in advance, which increases the possibility of later failures. Summary of the invention

[0007] In order to solve the above technical problems, the present invention proposes a low chromium alloy centrifugal composite cast steel support roller anti-stripping test method, comprising the following steps: S1. preparing test samples of different parts of the low chromium alloy centrifugal composite cast steel support roller, and pretreating the test samples of different parts; S2. Perform pressure tests on the test samples at different locations after pretreatment to determine the corresponding limit pressures at different locations; S3, using the corresponding limit pressures of different parts obtained in step S2, measuring the coating adhesion of the test samples at various parts of the low-chromium alloy centrifugal composite cast steel support roller; S4. Increase the ultimate pressure obtained in step S2 by 5%-10%, evaluate the debonding of the coating substrate interface through numerical simulation, and determine the breakthrough ultimate pressure when the adhesive unit will fail.

[0008] Furthermore, in step S3, the coating adhesion G is calculated by the following formula:

[0009] in, is the Poisson’s ratio of the coating material in the test sample, E f is the elastic modulus, b is the indenter contact length, A is the indenter contact area, t is the thickness of the coating in the test sample, P is the ultimate pressure, and a is the imprint depth.

[0010] Furthermore, in step S2, gradually increasing pressure is applied to different test samples until a mark appears, and the minimum pressure that causes the mark to be formed is recorded as the limit pressure of the part.

[0011] Furthermore, an adhesive unit is introduced at the interface between the coating and the substrate. The stress distribution on the coating-substrate interface is analyzed through numerical simulation technology when the ultimate pressure calculated in step S2 increases by 5%-10%. An adhesive evolution model is established for the coating-substrate bonding interface, and the breakthrough ultimate pressure that causes the failure of the adhesive unit is calculated.

[0012] Furthermore, assuming that the material is isotropic, the adhesion evolution model is expressed by the following equation:

[0013]

[0014] In the formula, is the interfacial peeling stress; D is the adhesion accumulated damage stiffness; For peeling displacement; is the critical displacement at the beginning of damage; K is the initial interface stiffness; interface delamination occurs when the cohesive force accumulates damage stiffness D=1; is the displacement when the cohesive unit fails completely.

[0015] Furthermore, when the peel displacement exist When the adhesive unit is within the range, linear elastic deformation occurs, and the adhesive unit is not damaged. At this time, the unloading returns to the origin along the original path; When the peel displacement Exceeding critical displacement ,exist When the range is greater than 0.04, the adhesive unit is damaged and a part of the adhesive potential energy is released. This stage is the damage evolution. When the peel displacement Exceed , the adhesive unit will fail, break and disappear, and completely release the adhesive potential energy : ; in, is the critical stress at which damage begins.

[0016] Furthermore, in the step S1, test samples are cut from the end, middle and connecting parts of the low-chromium alloy centrifugal composite cast steel support roller, and the samples are cleaned.

[0017] Furthermore, in step S2, the relationship between the pressure p of the pressure head and the mark depth a is recorded in real time, a pa curve is generated, the inflection point where the mark depth suddenly accelerates when the pressure increases is identified, marked as the sudden change point, and the pressure corresponding to the sudden change point of each part is recorded, which is the corresponding limit pressure P of different parts.

[0018] Furthermore, the pressure test in step S2 adopts a Vickers hardness test or a Rockwell hardness test.

[0019] Compared with the prior art, the present invention has the following beneficial technical effects: 1. The accuracy and reliability of the test are ensured by preparing and pre-treating the test samples at different parts, which helps to understand the real performance of each part of the support roller more comprehensively.

[0020] 2. Carry out pressure tests at different parts and determine the limit pressure, which enables accurate assessment of the maximum bearing capacity of each part, thereby optimizing the design and preventing failures caused by local overload in actual applications.

[0021] 3. By measuring the coating adhesion, we can understand the degree of bonding between the coating and the base material, which is crucial to ensure the long-term stable operation of the support roller. Good adhesion means that the coating is not likely to fall off during use.

[0022] 4. By appropriately increasing the ultimate pressure for numerical simulation, we can simulate extreme conditions close to actual working conditions, thereby evaluating the risk of delamination at the coating-substrate interface. This step helps to discover potential problems in the design stage, make adjustments in advance, and reduce the possibility of later failures. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0024] Figure 1 It is a schematic flow chart of the anti-stripping test method of the low chromium alloy centrifugal composite cast steel support roller of the present invention; Figure 2 Schematic diagram of different positions of low chromium alloy centrifugal composite cast steel support roller; Figure 3 It is a schematic diagram of the pressure device of the present invention; Figure 4 A schematic diagram of the marks that appear when the pressure is gradually increased on the test sample of the present invention; Figure 5 It is a schematic diagram of the adhesion evolution model of the present invention.

[0025] Description of the reference numerals: end portion 2; middle portion 3; connecting portion 4. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0027] In the drawings of the specific embodiments of the present invention, in order to better and more clearly describe the working principles of the various components in the system, the connection relationship of the various parts in the device is shown, which only clearly distinguishes the relative position relationship between the various components, and cannot constitute a limitation on the signal transmission direction, connection sequence and structural size, size and shape of each part within the component or structure.

[0028] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments. Example 1 like Figure 1 FIG. 1 is a schematic flow chart of a method for testing the anti-stripping of a low-chromium alloy centrifugal composite cast steel support roller according to Example 1. The method for testing the anti-stripping of a low-chromium alloy centrifugal composite cast steel support roller comprises the following steps: S1: Prepare test samples of different parts of the low chromium alloy centrifugal composite cast steel support roller, and pretreat the test samples of different parts.

[0029] Test samples were cut from different positions of the low chromium alloy centrifugal composite cast steel support roll, such as Figure 2 The different parts shown, such as the end part 2, the middle part 3 and the connecting part 4, ensure that the sample can fully reflect the local material properties and structural characteristics of the support roller.

[0030] The samples are properly processed to eliminate defects that may occur during the cutting process and to ensure that the surface flatness and size of the samples meet the test requirements.

[0031] Clean the sample to remove oil, dust and other impurities on the surface to ensure the accuracy of the test results. If necessary, perform surface roughness treatment on the sample to meet the requirements of specific test methods.

[0032] S2. Perform pressure tests on the test samples at different locations after pretreatment to determine the corresponding limit pressures at different locations.

[0033] like Figure 3 As shown, a pressure device is used to apply pressure to the test sample at different locations.

[0034] Apply gradually increasing pressure to different test samples until marks appear, e.g. Figure 4 As shown, record the minimum pressure that causes the mark to form, which is the limit pressure of this part. Since the working environment and stress conditions of each part of the support roller may be different, different parts will have their own specific limit pressure.

[0035] Specifically, the pressure applied to the test sample is gradually increased, and a curve of the corresponding relationship between the pressure and the mark depth is recorded.

[0036] Observe whether there are points on the curve where the depth of the imprint changes suddenly. These sudden change points correspond to the limit mode of the coating material. According to the sudden change points on the curve, determine the corresponding limit pressure.

[0037] In a preferred embodiment, the pressure test is a Vickers hardness test, which uses a diamond regular tetrahedron indenter with a relative surface angle of 136° to press into the surface of the test sample under a specified load, and then remove the load after a certain period of time to measure the depth of the mark.

[0038] In a preferred embodiment, the pressure test is a Rockwell hardness test, and a diamond cone or hardened steel ball indenter is used. Under the action of the test pressure, the indenter is pressed into the material surface. After maintaining the pressure for a specified time, the main test force is removed, the initial test force is maintained, and the residual mark depth increment is measured.

[0039] S3. Using the corresponding limit pressures of different parts obtained in S2, the coating adhesion of the test samples of various parts of the low-chromium alloy centrifugal composite cast steel support roller is determined.

[0040] This step can help understand the adhesion strength between the coating and the substrate.

[0041] In the prior art, the interfacial peeling method is usually used to measure the film adhesion, which destroys the bond between the material and the substrate by applying external tensile or shear force; there is also a stretching method, which destroys the bond between the material and the substrate by applying a tensile force, and measures the applied tensile force and the fracture area to calculate the peel strength; there is also a shearing method, which destroys the bond between the material and the substrate by applying a shear force, and measures the applied shear force and the bonding area to calculate the peel strength.

[0042] In this embodiment, the coating adhesion of the test sample at each position of the low-chromium alloy centrifugal composite cast steel support roller is measured by applying corresponding limit pressure at different positions.

[0043] When the indenter contacts the test sample, the contact area is A and the indenter contact length is b.

[0044] Poisson's ratio of the material of the coating in the test sample , elastic modulus E f .

[0045] The thickness t of the coating in the test sample.

[0046] The imprint depth is denoted by a and is measured by transmission electron microscopy, and the ultimate pressure is denoted by P.

[0047] The measured coating adhesion G can be calculated by the following formula:

[0048] In this way, accurate testing of coating adhesion is achieved through calculation.

[0049] S4. Increase the ultimate pressure obtained in step S2 by 5%-10%, evaluate the coating-substrate interface peeling through numerical simulation, and determine the breakthrough ultimate pressure at which the adhesive unit will fail.

[0050] Specifically, in order to accurately evaluate the peeling condition between the coating-substrate system, this embodiment introduces an adhesion unit at the interface between the coating and the substrate, evaluates the peeling condition of the coating-substrate interface through numerical simulation, and analyzes the influence of the adhesion performance between the coating and the substrate on its stress condition and interface stratification based on pressure simulation.

[0051] The delamination behavior of the interface between the coating and the substrate can be described by the stress peeling criterion. The present invention uses finite element analysis software to establish a bonding evolution model for the interface between the coating and the substrate, such as Figure 5 shown.

[0052] Set the material properties and boundary conditions, input the ultimate pressure data obtained from step S2, and increase it by 5%-10% as the simulation input.

[0053] As shown in the figure above, assuming that the material is isotropic, the adhesion evolution model can be expressed by the following equation:

[0054]

[0055] In the formula, is the interfacial peeling stress; D is the adhesion accumulated damage stiffness; For peeling displacement; is the critical displacement at the beginning of damage; K is the initial interface stiffness; interface delamination occurs when the cohesive force accumulates damage stiffness D=1; is the displacement when the cohesive unit fails completely.

[0056] By using numerical simulation technology, the stress distribution on the coating-substrate interface is analyzed when the ultimate pressure calculated in step S2 increases by 5%-10%: When the peel displacement exist When the adhesive unit is within the range of , the linear elastic deformation occurs, and the adhesive unit is not damaged. At this time, the unloading returns to the origin O along the original path.

[0057] When the peel displacement Exceeding critical displacement ,exist When the range reaches 0.0400, the adhesive unit is damaged and a part of the adhesive potential energy is released. This stage is the damage evolution.

[0058] When the peel displacement Exceed , the adhesive unit will fail, break and disappear, and completely release the adhesive potential energy , which is the work required to make the coating-substrate interface fail, can be Figure 5 The shaded area is represented by: .

[0059] in, is the critical stress at which damage begins.

[0060] Peel displacement Exceed The interfacial peeling stress at is the breakthrough limit pressure that completely causes the coating-substrate interface to peel off.

[0061] Thus, the breakthrough limit pressure that completely causes the coating-substrate interface to peel off can be determined.

[0062] Example 2 Based on Example 1, the preferred implementation steps of step S2 are as follows: Observing the sudden change point on the pressure-imprint depth (pa) curve can help identify the situation where the material begins to undergo plastic deformation. The specific steps for observing the sudden change point of the pressure-imprint depth curve are as follows: (1) Data Recording During the pressure test, the relationship between the pressure (P) of the indenter and the imprint depth (A) is recorded in real time to generate a PA curve graph, in which the horizontal axis represents the imprint depth and the vertical axis represents the applied load.

[0063] (2) Curve analysis Look at the PA curve and pay attention to the overall trend of the curve and any significant changes; look for inflection points on the curve or places where the slope changes greatly, which may be signs of the onset of plastic deformation.

[0064] Pay special attention to those points where the depth of the imprint increases suddenly and sharply with increasing load, which may indicate plastic flow of the material.

[0065] (3) Identification of sudden change points The sudden change points appear as discontinuous changes on the curve. For example, when the pressure increases, the depth of the mark suddenly increases rapidly. These sudden change points can be marked manually or software tools can be used to assist in identification.

[0066] (4) Confirmation of the sudden change point Use the zoom function to carefully check the curve details near the suspected sudden change point to confirm its authenticity. For complex curves, multi-angle analysis is required, combined with SEM images to confirm the nature of the sudden change point.

[0067] (5) Data analysis Record the pressure corresponding to the sudden change point of each part, analyze it, compare the test results of different parts, and find commonalities or differences.

[0068] In one embodiment, a computer device is further provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above method embodiments when executing the computer program.

[0069] In one embodiment, a computer-readable storage medium is provided, storing a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0070] In one embodiment, a computer program product or computer program is provided, the computer program product or computer program includes computer instructions, the computer instructions are stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device performs the steps in the above-mentioned method embodiments.

[0071] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0072] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0073] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for testing the anti-stripping of a low-chromium alloy centrifugal composite cast steel support roller, characterized in that: The steps include: S1. preparing test samples of different parts of the low chromium alloy centrifugal composite cast steel support roller, and pretreating the test samples of different parts; S2. Perform pressure tests on the test samples at different locations after pretreatment to determine the corresponding limit pressures at different locations; S3, using the corresponding limit pressures of different parts obtained in step S2, measuring the coating adhesion of the test samples at various parts of the low-chromium alloy centrifugal composite cast steel support roller; S4. Increase the ultimate pressure obtained in step S2 by 5%-10%, evaluate the debonding of the coating substrate interface through numerical simulation, and determine the breakthrough ultimate pressure when the adhesive unit will fail.

2. The anti-peeling test method according to claim 1, characterized in that: In step S3, the coating adhesion G is calculated by the following formula: in, is the Poisson’s ratio of the coating material in the test sample, E f is the elastic modulus, b is the indenter contact length, A is the indenter contact area, t is the thickness of the coating in the test sample, P is the ultimate pressure, and a is the imprint depth.

3. The anti-peeling test method according to claim 1, characterized in that: In step S2, gradually increasing pressure is applied to different test samples until a mark appears, and the minimum pressure that causes the mark to form is recorded as the limit pressure of the part.

4. The anti-peeling test method according to claim 3, characterized in that: An adhesive unit is introduced at the interface between the coating and the substrate. The stress distribution on the coating-substrate interface is analyzed through numerical simulation technology when the ultimate pressure calculated in step S2 increases by 5%-10%. An adhesive evolution model is established for the coating-substrate bonding interface, and the breakthrough ultimate pressure that causes the failure of the adhesive unit is calculated.

5. The anti-peeling test method according to claim 4, characterized in that: Assuming the material is isotropic, the adhesion evolution model is expressed by the following equation: In the formula, is the interfacial peeling stress; D is the adhesion accumulated damage stiffness; For peeling displacement; is the critical displacement at the beginning of damage; K is the initial interface stiffness; interface delamination occurs when the cohesive force accumulates damage stiffness D=1; is the displacement when the cohesive unit fails completely.

6. The anti-peeling test method according to claim 5, characterized in that: When the peel displacement exist When the adhesive unit is within the range, linear elastic deformation occurs, and the adhesive unit is not damaged. At this time, the unloading returns to the origin along the original path; When the peel displacement Exceeding critical displacement ,exist When the range is greater than 0.04, the adhesive unit is damaged and a part of the adhesive potential energy is released. This stage is the damage evolution. When the peel displacement Exceed , the adhesive unit will fail, break and disappear, and completely release the adhesive potential energy : ； in, is the critical stress at which damage begins.

7. The anti-peeling test method according to claim 1, characterized in that: In the step S1, test samples are cut from the end, middle and connecting parts of the low chromium alloy centrifugal composite cast steel support roller, and the samples are cleaned.

8. The anti-peeling test method according to claim 2, characterized in that: In step S2, the relationship between the pressure p of the pressure head and the mark depth a is recorded in real time, a pa curve is generated, the inflection point where the mark depth suddenly accelerates when the pressure increases is identified, marked as the sudden change point, and the pressure corresponding to the sudden change point of each part is recorded, which is the corresponding limit pressure P of different parts.

9. The anti-peeling test method according to claim 1, characterized in that: The pressure test in step S2 adopts a Vickers hardness test or a Rockwell hardness test.

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