Casting blank surface crack prediction method and device, equipment and medium

Abstract

The invention provides a casting blank surface crack prediction method, device, equipment and medium, and relates to the technical field of steel continuous casting, the method comprises the following steps: determining an actual critical strain value according to an obtained test critical strain value and strain impact factors, the strain impact factors comprising a grain size factor, a component segregation factor and a notch factor; determining a critical strain rate according to the obtained material properties, machine parameters and process conditions; and generating a crack prediction result by adopting a damage integral method according to the actual critical strain value and the critical strain rate. According to the method, various factors influencing crack formation are comprehensively considered, a more accurate prediction method is provided, a large amount of experimental data is not needed, technicians do not need to have casting experience, and the prediction cost is greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of steel continuous casting, and in particular to a method, device, equipment and medium for predicting surface cracks of a casting blank. Background Art

[0002] In the steel continuous casting process, surface cracks on the ingot are an important issue because their appearance will significantly increase the cost of adjusting and repairing the ingot before rolling, and may pass defects to subsequent rolled products, affecting product quality. Severe cracks may also cause the ingot to be scrapped or cause steel leakage, which will interrupt the casting process and lead to the need for equipment maintenance, resulting in a waste of time and resources. The formation of cracks is mainly caused by two factors: one is the brittle characteristics of steel in a specific temperature range, which is the physical property of the material itself; the other is the complex strain and stress state caused by specific solidification conditions during the casting process. These mechanical conditions work together to aggravate the occurrence and development of cracks.

[0003] In the prior art, tensile tests are generally used to evaluate the sensitivity of different steel grades to cracks. The test is carried out under strictly controlled parameters such as deformation temperature and strain rate to determine the relationship between the cross-sectional shrinkage and temperature of the steel grade on the casting machine. Based on the relationship between the cross-sectional shrinkage and temperature and the casting experience of the technicians, the appearance of surface cracks on the billet is predicted, and the surface temperature of the round billet when passing through the key machine area is adjusted to prevent the appearance of surface cracks on the billet. Although this method can predict the appearance of surface cracks on the billet, it requires the technicians to have considerable casting experience and a large amount of experimental data, and the relationship between the cross-sectional shrinkage and temperature of steel grades on different casting machines is also different. Each casting machine requires multiple experiments to obtain the relationship between the cross-sectional shrinkage and temperature, resulting in excessively high prediction costs for surface cracks on the billet. Summary of the invention

[0004] The problem solved by the invention is how to reduce the prediction cost of surface cracks of the casting slab.

[0005] In order to solve the above problems, in a first aspect, the present invention provides a method for predicting surface cracks of a casting billet, comprising:

[0006] Determine the actual critical strain value according to the obtained experimental critical strain value and strain influence factor, wherein the strain influence factor includes grain size factor, component segregation factor and notch factor;

[0007] Determine the critical strain rate based on the acquired material properties, machine parameters and process conditions;

[0008] According to the actual critical strain value and the critical strain rate, a damage integration method is used to generate a crack prediction result.

[0009] Optionally, the generating a crack prediction result by using a damage integration method according to the actual critical strain value and the critical strain rate includes:

[0010] Obtaining a deformation time of a surface of a casting billet, and dividing the deformation time into at least two sub-deformation times;

[0011] According to the actual critical strain value and the critical strain rate, the damage integral method is used to respectively determine the sub-surface damage of each of the sub-deformation times, and a total surface damage is generated according to all the sub-surface damages;

[0012] The crack prediction result is generated according to the total surface damage.

[0013] Optionally, generating the crack prediction result according to the total surface damage includes:

[0014] According to the total surface damage, a crack criterion formula is used to generate the crack prediction result, and the crack criterion formula includes:

[0015]

[0016] Wherein, t1 is the start time, t is the sub-deformation time, is the critical strain rate, εcrit is the actual critical strain value, is the total surface damage.

[0017] Optionally, determining the actual critical strain value according to the obtained test critical strain value and strain influence factor includes:

[0018] According to the test critical strain value and the strain influence factor, the actual critical strain value is determined by using the actual critical strain value formula, and the actual critical strain value formula includes:

[0019]

[0020] Among them, ε crit is the actual critical strain value, ε crit (tensile test) is the critical strain value of the test, f grainsize is the grain size factor, f segregation is the component segregation factor, f notch is the incision factor.

[0021] Optionally, determining the critical strain rate according to the acquired material properties, machine parameters and process conditions includes:

[0022] According to the material properties, the machine parameters and the process conditions, the critical strain rate is determined using a critical strain rate formula, wherein the critical strain rate formula includes:

[0023]

[0024] in, is the critical strain rate, R is the casting machine radius of the machine parameter, x is the radial coordinate of the machine parameter, and the origin is located at the casting machine center, v c is the casting speed of the process conditions, Z is the material property, C is the coefficient, is the rate of change of the casting machine radius R with the material property Z.

[0025] Optionally, before determining the actual critical strain value according to the obtained test critical strain value and strain influence factor, the method further includes:

[0026] Determine the section shrinkage rate based on the existing test data;

[0027] The test critical strain value is determined according to the cross-sectional shrinkage rate.

[0028] Optionally, determining the test critical strain value according to the cross-sectional shrinkage rate includes:

[0029] According to the cross-sectional shrinkage rate, the test critical strain value is determined by using a test critical strain value formula group, and the test critical strain value formula group includes:

[0030]

[0031] Wherein, RA is the cross-sectional shrinkage, D0 is the diameter of the ingot before the test, and D f is the fracture diameter of the ingot before the test.

[0032] In a second aspect, the present invention provides a device for predicting surface cracks of a casting, comprising:

[0033] An actual critical strain value module is used to determine the actual critical strain value according to the obtained experimental critical strain value and strain influence factor, wherein the strain influence factor includes a grain size factor, a component segregation factor and a notch factor;

[0034] Critical strain rate module, used to determine the critical strain rate based on the acquired material properties, machine parameters and process conditions;

[0035] The loss prediction module is used to generate a crack prediction result by using a damage integration method according to the actual critical strain value and the critical strain rate.

[0036] In a third aspect, the present invention provides an electronic device, including a memory and a processor;

[0037] The memory is used to store computer programs;

[0038] The processor is used to implement the method for predicting surface cracks of the casting billet as described in the first aspect when executing the computer program.

[0039] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method for predicting surface cracks of a casting billet as described in the first aspect is implemented.

[0040] The method, device, electronic device and storage medium for predicting surface cracks of a casting blank of the present invention have the following beneficial effects:

[0041] According to the obtained experimental critical strain value and strain influence factor, the actual critical strain value is determined, and multiple influencing factors, namely, grain size factor, component segregation factor and notch factor, are considered, which can more accurately reflect the material behavior in the actual production environment, improve the accuracy of crack prediction, and at the same time, reduce the number of unnecessary experiments and reduce the trial and error cost. According to the obtained material properties, machine parameters and process conditions, the critical strain rate of the straightening and bending strain of the billet can be determined, which is convenient for considering the influence of the straightening and bending strain of the billet on the surface cracks of the billet in the subsequent analysis. Finally, the damage integral method is adopted to apply the actual critical strain value and the critical strain rate to the transient conditions to evaluate the damage accumulation of the billet during the continuous casting process, so as to predict the possibility of cracking and obtain accurate crack prediction results. The present invention provides a more accurate prediction method by comprehensively considering various factors affecting crack formation, which can reduce the requirements for the number of experimental data and the casting experience of technicians, and greatly reduce the prediction cost of the surface cracks of the billet. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A schematic flow chart of a method for predicting surface cracks of a casting blank provided by an embodiment of the present invention;

[0043] Figure 2 A schematic diagram of the structure of a device for predicting surface cracks of a casting blank provided by an embodiment of the present invention;

[0044] Figure 3 A schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0045] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be interpreted as being limited to the embodiments described herein. On the contrary, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0046] It should be understood that the various steps described in the method embodiments of the present invention may be performed in different orders and / or in parallel. In addition, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present invention is not limited in this respect.

[0047] The term "including" and its variations used in this document are open inclusions, that is, "including but not limited to"; the term "based on" means "based at least in part on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first", "second", etc. mentioned in the present invention are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.

[0048] It should be noted that the modifications of "one" and "plurality" mentioned in the present invention are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0049] The names of the messages or information exchanged between multiple devices in the embodiments of the present invention are only used for illustrative purposes, and are not used to limit the scope of these messages or information.

[0050] In the steel continuous casting process, the appearance of surface cracks on the ingot is considered an extremely unfavorable condition. It not only significantly increases the economic cost of adjusting and repairing the ingot before rolling, but also hides the risk of transferring defects to subsequent rolled products, thereby affecting product quality. If the existence of such cracks is ignored, it may even force the ingot to be scrapped in severe cases. What's worse, severe cracks may also cause steel leakage, which will directly interrupt the casting process and trigger the need for maintenance of production equipment, resulting in a double waste of time and resources. The root cause of crack formation can be attributed to two major factors: one is the brittle characteristics of steel itself in a specific temperature range, which is the inherent physical property of the material; the other is the complex strain and stress state generated by specific solidification conditions during the casting process. These dynamic mechanical conditions work together to increase the possibility of crack initiation and expansion. In order to accurately evaluate the sensitivity of different steel grades to cracks, the industry generally uses tensile tests as a standard method. The test is carried out under strictly controlled parameters such as deformation temperature and strain rate, and the cross-sectional shrinkage rate after the specimen is fractured is used as a key indicator to measure the ductility of the ingot material. When the cross-sectional shrinkage rate is low, it means that the ingot material is easy to tear during the stretching process and exhibits high brittleness; conversely, if the cross-sectional shrinkage rate value is close to 100%, it indicates that the ingot material has undergone significant shrinkage (i.e., the final cross-sectional area after fracture is small) and has good ductility.

[0051] Based on the above-mentioned relationship between section reduction and temperature, technicians in continuous casting plants can adjust the surface temperature of the billet when it passes through the key machine area to ensure that it has sufficient ductility, thereby effectively preventing the formation of cracks. Studies have shown that for a specific round billet grade, when the surface temperature of the round billet is maintained within a specific temperature range that makes the section reduction rate higher than 75%, the bending cracks and network cracks that occur on a specific machine can be significantly reduced. Therefore, in actual operation, by implementing a low-temperature enhanced cooling strategy (usually below 700°C), it is possible to ensure that this type of steel can be cast smoothly on a specific casting machine without worrying about the problem of cracks. Therefore, the section reduction rate and temperature relationship diagram is successfully used in many plants to optimize secondary cooling to avoid certain types of cracks. However, this simple method requires considerable casting experience and the collection of a large amount of crack data to establish the relationship between the crack problems occurring on the casting machine and the laboratory section reduction rate and temperature curve, and this relationship is different for each machine. Therefore, the prediction method of the prior art is too complicated and requires a large amount of data, which is too costly.

[0052] In addition, there are some difficulties in directly applying the relationship between cross-sectional shrinkage and temperature to actual continuous casting. During the continuous casting process, the surface temperature and strain rate of the billet, such as a round billet, change along the billet. Therefore, the billet deformation occurs under variable thermomechanical conditions, while the deformation in the tensile test is usually carried out at a constant temperature and a constant strain rate. Therefore, the existing prediction methods are not very accurate.

[0053] In view of the problems existing in the above-mentioned related technologies, this embodiment provides a method, device, equipment and medium for predicting surface cracks of a casting billet.

[0054] like Figure 1 As shown, a method for predicting surface cracks of a casting blank provided by an embodiment of the present invention comprises:

[0055] The actual critical strain value is determined according to the obtained experimental critical strain value and strain influence factor, wherein the strain influence factor includes a grain size factor, a component segregation factor and a notch factor.

[0056] Specifically, the experimental critical strain value is obtained through the existing experimental data. The experimental critical strain value is a key parameter obtained from the stress-strain curve of the tensile test. It represents a specific strain point at which the microstructural difference between the constrained and unconstrained parts of the specimen remains small despite the rapid contraction of the material due to uniform temperature and the development of the microstructure (especially the precipitation of austenite grain boundary nitrides along the length of the specimen) in the same way. In simple terms, the experimental critical strain value measures the degree of uniform longitudinal strain experienced by the tensile specimen before fracture. The formation of surface cracks in the ingot is the result of the combined action of multiple factors. In addition to the known factors, the local variation of austenite grain size, the composition segregation in the oscillation mark area, and the notch effect caused by the oscillation mark itself on the material are all non-negligible crack-promoting factors. In particular, transverse cracks are more common at the oscillation mark, where the cooling rate in the mold is relatively slow due to the thickening of the gap, which leads to the uneven distribution of thermal strain. Therefore, the grain size factor, component segregation factor and notch factor are used as crack promoting factors, combined with the experimental critical strain value, to determine the more complex but closer to the actual situation actual critical strain value, so as to provide more accurate theoretical support for the prediction of surface cracks in the ingot.

[0057] The critical strain rate is determined based on the acquired material properties, machine parameters and process conditions.

[0058] Specifically, the formation of transverse cracks on the surface of the ingot is mainly attributed to the complex interaction of thermal strains with the straightening and bending strains of the ingot. When the surface material cools significantly faster than the underlying material, significant thermal tensile strains will be generated, which causes the surface of the ingot to tend to shrink. However, due to the slower cooling rate of the underlying material, the surface material is constrained and its free shrinkage is hindered. In other words, the formation of transverse corner cracks is directly caused by this thermal strain difference, because the corner area tends to cool faster than the adjacent billet surface due to its geometry and heat dissipation conditions. These corner areas have a tendency to shrink in the longitudinal direction, but they cannot be realized due to the constraints of the surface material, resulting in the total strain tending to zero (or very close to zero). In order to maintain this strain balance, viscoplastic (creep) strains will intervene to offset the effects of thermal strains, so the effect of thermal strains on the critical strain rate can be ignored. As for the straightening and bending strains of the ingot, their generation and size are highly dependent on the specific type and design of the continuous casting machine. In arc-type continuous casting machines using curved crystallizers, the straightening process usually occurs at the end of the machine. However, in some designs, the straightening process may start below the die to relieve the subsequent straightening stress. Therefore, after obtaining the material properties, machine parameters and process conditions, the strain rate generated during the straightening and bending of the billet can be determined based on the material properties, machine parameters and process conditions.

[0059] According to the actual critical strain value and the critical strain rate, a damage integration method is used to generate a crack prediction result.

[0060] Specifically, the core of the damage integration method lies in flexibly and cleverly applying the critical strain data measured under isothermal conditions, namely the actual critical strain value and critical strain rate, to more complex transient continuous casting conditions, thereby constructing a prediction criterion for surface cracking of the continuous casting billet and generating crack prediction results.

[0061] In this embodiment, the actual critical strain value is determined according to the obtained experimental critical strain value and strain influence factor, and multiple influence factors, namely, grain size factor, component segregation factor and notch factor, are considered, which can more accurately reflect the material behavior in the actual production environment, improve the accuracy of crack prediction, and at the same time, reduce unnecessary experimental times and reduce trial and error costs. According to the obtained material properties, machine parameters and process conditions, the critical strain rate of the straightening and bending strain of the billet can be determined, which is convenient for considering the influence of the straightening and bending strain of the billet on the surface cracks of the billet in the subsequent analysis. Finally, the damage integral method is adopted to apply the actual critical strain value and the critical strain rate to transient conditions to evaluate the damage accumulation of the billet during the continuous casting process, so as to predict the possibility of cracking and obtain accurate crack prediction results. The present invention provides a more accurate prediction method by comprehensively considering various factors affecting crack formation, which not only does not require a large amount of experimental data, but also does not require the technician to have casting experience, greatly reducing the prediction cost.

[0062] Optionally, the generating a crack prediction result by using a damage integration method according to the actual critical strain value and the critical strain rate includes:

[0063] Obtaining a deformation time of a surface of a casting billet, and dividing the deformation time into at least two sub-deformation times;

[0064] According to the actual critical strain value and the critical strain rate, the damage integral method is used to respectively determine the sub-surface damage of each of the sub-deformation times, and a total surface damage is generated according to all the sub-surface damages;

[0065] The crack prediction result is generated according to the total surface damage.

[0066] Specifically, the deformation time refers to the time required for the surface elements of the ingot to pass through the continuous casting machine. The deformation time is divided into a series of small sub-deformation times. In each sub-deformation time, the amount of "damage" sustained by the surface elements, that is, the sub-surface damage, is calculated, and all sub-surface damages are accumulated to finally obtain the total surface damage. The total surface damage is used as the evaluation basis for predicting cracks to obtain crack prediction results.

[0067] Optionally, generating the crack prediction result according to the total surface damage includes:

[0068] According to the total surface damage, a crack criterion formula is used to generate the crack prediction result, and the crack criterion formula includes:

[0069]

[0070] Wherein, t1 is the start time, t is the sub-deformation time, is the critical strain rate, εcrit is the actual critical strain value, is the total surface damage.

[0071] Specifically, the start time can be defined as the time when the cross-sectional reduction rate reaches a certain value, for example, the time when it reaches 75%. The accumulated damage on the surface of the ingot is:

[0072]

[0073] Among them, L is also the total surface damage, and the accumulated strain is:

[0074]

[0075] Therefore, the accumulated strain can also be expressed as Lε crit , so it can be determined that if the accumulated strain is equal to ε crit Cracking will occur when L=1, thus obtaining the cracking criterion formula. When the total surface damage is greater than or equal to 1, the parameter crack is determined.

[0076] For example, in the above formula, the increment of deformation strain, that is, the increment of surface damage, is assigned different weights, which are determined based on the ratio of the actual conditions existing in a specific time step to the corresponding critical strain, such as temperature, strain rate, etc. This weighting method is intended to more accurately reflect the contribution of strain to material damage under different conditions. In addition, based on a deep understanding of specific cracking mechanisms, strain rates can be selectively applied to further refine damage assessments. Specifically, the absolute value of the strain rate can be used to assume the consistency of micro-slip and aluminum particle precipitation behavior in tensile and compressive deformations, or only the tensile strain rate can be considered, or both the tensile and compressive strain rates can be considered but assigned different weighting factors. This flexibility enables the damage integration method to be closer to actual working conditions and improve the accuracy and reliability of cracking predictions.

[0077] Optionally, determining the actual critical strain value according to the obtained test critical strain value and strain influence factor includes:

[0078] According to the test critical strain value and the strain influence factor, the actual critical strain value is determined by using the actual critical strain value formula, and the actual critical strain value formula includes:

[0079]

[0080] Among them, ε crit is the actual critical strain value, ε crit (tensile test) is the critical strain value of the test, f grainsize is the grain size factor, fsegregation is the component segregation factor, f notch is the incision factor.

[0081] Specifically, by taking into account the local changes in austenite grain size, the composition segregation in the oscillation mark area, and the notch effect caused by the oscillation mark itself on the material, the actual critical strain value that is closer to the actual situation can be determined, so as to facilitate more accurate crack prediction.

[0082] Optionally, determining the critical strain rate according to the acquired material properties, machine parameters and process conditions includes:

[0083] According to the material properties, the machine parameters and the process conditions, the critical strain rate is determined using a critical strain rate formula, wherein the critical strain rate formula includes:

[0084]

[0085] in, is the critical strain rate, R is the casting machine radius of the machine parameter, x is the radial coordinate of the machine parameter, and the origin is located at the casting machine center, v c is the casting speed of the process conditions, Z is the material property, C is the coefficient, is the rate of change of the casting machine radius R with the material property Z.

[0086] Specifically, according to the critical strain rate formula that takes into account material properties, machine parameters and process conditions, an accurate critical strain rate can be obtained. Wherein, Rx is the distance.

[0087] Optionally, before determining the actual critical strain value according to the obtained test critical strain value and strain influence factor, the method further includes:

[0088] Determine the section shrinkage rate based on the existing test data;

[0089] The test critical strain value is determined according to the cross-sectional shrinkage rate.

[0090] Specifically, based on existing test data, such as an existing tensile test, a stress-strain curve is obtained to determine the cross-sectional shrinkage rate, and then the test critical strain value is derived.

[0091] Optionally, determining the test critical strain value according to the cross-sectional shrinkage rate includes:

[0092] According to the cross-sectional shrinkage rate, the test critical strain value is determined by using a test critical strain value formula group, and the test critical strain value formula group includes:

[0093]

[0094] Wherein, RA is the cross-sectional shrinkage, D0 is the diameter of the ingot before the test, and D f is the fracture diameter of the ingot before the test.

[0095] Specifically, the experimental critical strain value formula group is used to facilitate the derivation of an accurate experimental critical strain value. For example, RA can also be determined according to a theoretical formula:

[0096]

[0097] Among them, a, b, c and d are coefficients, T is the deformation temperature, T f It is the temperature corresponding to when the cross-sectional shrinkage rate reaches 100%.

[0098] Exemplarily, the present invention provides a specific example to explain the prediction process of the method for predicting surface cracks of a casting billet. The casting billet is a round billet with a diameter of 300 mm as an example, and its material composition includes 0.25% carbon, 0.12% silicon, 2.1% manganese, 0.035% phosphorus and 0.0036% sulfur, the billet drawing speed is 1.5 m / min, and the casting machine radius is 12 m. First, according to the above-mentioned experimental critical strain value formula group, or the experimental critical strain value formula and the theoretical formula in the experimental critical strain value formula group, the cross-sectional shrinkage rate and the experimental critical strain value are determined, and then according to the cross-sectional shrinkage rate and the experimental critical strain value, the actual critical strain value formula is used to obtain Then, according to various parameters, the critical strain rate is determined, and the maximum critical strain rate is about 3×10 -3 s -1 Finally, according to the actual critical strain value and critical strain rate, the total surface damage is calculated as Therefore, the prediction result is that there is a risk of cracking.

[0099] like Figure 2 As shown, a device 200 for predicting surface cracks of a casting blank provided by an embodiment of the present invention comprises:

[0100] The actual critical strain value module 210 is used to determine the actual critical strain value according to the obtained experimental critical strain value and the strain influence factor, wherein the strain influence factor includes a grain size factor, a component segregation factor and a notch factor;

[0101] A critical strain rate module 220, for determining a critical strain rate based on acquired material properties, machine parameters, and process conditions;

[0102] The loss prediction module 230 is used to generate a crack prediction result by using a damage integration method according to the actual critical strain value and the critical strain rate.

[0103] like Figure 3 As shown, an electronic device 300 provided by an embodiment of the present invention includes a memory 310 and a processor 320; the memory 310 is used to store a computer program; the processor 320 is used to implement the above-mentioned method for predicting surface cracks of a casting ingot when executing the computer program.

[0104] In other words, an electronic device 300 includes a memory 310 and a processor 320 coupled to the memory 310; the memory 310 is configured to store a computer program; and the processor 320 is configured to perform the following operations when executing the computer program:

[0105] Determine the actual critical strain value according to the obtained experimental critical strain value and strain influence factor, wherein the strain influence factor includes grain size factor, component segregation factor and notch factor;

[0106] Determine the critical strain rate based on the acquired material properties, machine parameters and process conditions;

[0107] According to the actual critical strain value and the critical strain rate, a damage integral method is used to generate a crack prediction result. An embodiment of the present invention provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the above-mentioned method for predicting surface cracks of a casting is implemented.

[0108] In other words, a non-volatile computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the processor performs the following operations:

[0109] Determine the actual critical strain value according to the obtained experimental critical strain value and strain influence factor, wherein the strain influence factor includes grain size factor, component segregation factor and notch factor;

[0110] Determine the critical strain rate based on the acquired material properties, machine parameters and process conditions;

[0111] According to the actual critical strain value and the critical strain rate, a damage integration method is used to generate a crack prediction result.

[0112] An electronic device 300 that can be used as a server or client of the present invention will now be described, which is an example of a hardware device that can be applied to various aspects of the present invention. The electronic device 300 is intended to represent various forms of digital electronic computer equipment, such as laptop computers, desktop computers, workbenches, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device 300 can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples, and are not intended to limit the implementation of the present invention described and / or required herein.

[0113] The electronic device 300 includes a computing unit, which can perform various appropriate actions and processes according to a computer program stored in a read-only memory (ROM) or a computer program loaded from a storage unit into a random access memory (RAM). In the RAM, various programs and data required for the operation of the device can also be stored. The computing unit, ROM, and RAM are connected to each other via a bus. An input / output (I / O) interface is also connected to the bus.

[0114] A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, the storage medium can be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc. In the present application, the unit described as a separate component may or may not be physically separated, and the component displayed as a unit may or may not be a physical unit, that is, it may be located in one place, or it may be distributed on multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiment of the present invention. In addition, each functional unit in each embodiment of the present invention can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

[0115] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A method for predicting surface cracks of a casting, characterized in that: include: Determine the actual critical strain value according to the obtained experimental critical strain value and strain influence factor, wherein the strain influence factor includes grain size factor, component segregation factor and notch factor; Determine the critical strain rate based on the acquired material properties, machine parameters and process conditions; According to the actual critical strain value and the critical strain rate, a damage integration method is used to generate a crack prediction result.

2. The method for predicting surface cracks of a casting according to claim 1, characterized in that: The method of generating a crack prediction result by using a damage integration method according to the actual critical strain value and the critical strain rate includes: Obtaining a deformation time of a surface of a casting billet, and dividing the deformation time into at least two sub-deformation times; According to the actual critical strain value and the critical strain rate, the damage integral method is used to respectively determine the sub-surface damage of each of the sub-deformation times, and a total surface damage is generated according to all the sub-surface damages; The crack prediction result is generated according to the total surface damage.

3. The method for predicting surface cracks of a casting according to claim 2, characterized in that: Generating the crack prediction result according to the total surface damage includes: According to the total surface damage, a crack criterion formula is used to generate the crack prediction result, and the crack criterion formula includes: Wherein, t1 is the start time, t is the sub-deformation time, is the critical strain rate, εcrit is the actual critical strain value, is the total surface damage.

4. The method for predicting surface cracks of a casting slab according to claim 1, characterized in that: Determining the actual critical strain value according to the obtained test critical strain value and strain influence factor includes: According to the test critical strain value and the strain influence factor, the actual critical strain value is determined by using the actual critical strain value formula, and the actual critical strain value formula includes: Among them, ε crit is the actual critical strain value, ε crit (tensile test) is the critical strain value of the test, f grainsize is the grain size factor, f segregation is the component segregation factor, f notch is the incision factor.

5. The method for predicting surface cracks of a casting according to claim 1, characterized in that: Determining the critical strain rate according to the acquired material properties, machine parameters and process conditions includes: According to the material properties, the machine parameters and the process conditions, the critical strain rate is determined using a critical strain rate formula, wherein the critical strain rate formula includes: in, is the critical strain rate, R is the casting machine radius of the machine parameter, x is the radial coordinate of the machine parameter, and the origin is located at the casting machine center, v c is the casting speed of the process conditions, Z is the material property, C is the coefficient, is the rate of change of the casting machine radius R with the material property Z.

6. The method for predicting surface cracks of a casting according to claim 1, characterized in that: Before determining the actual critical strain value according to the obtained test critical strain value and strain influence factor, the method further includes: Determine the section shrinkage rate based on the existing test data; The test critical strain value is determined according to the cross-sectional shrinkage rate.

7. The method for predicting surface cracks of a casting according to claim 6, characterized in that: Determining the test critical strain value according to the cross-sectional shrinkage rate includes: According to the cross-sectional shrinkage rate, the test critical strain value is determined by using a test critical strain value formula group, and the test critical strain value formula group includes: Wherein, RA is the cross-sectional shrinkage, D0 is the diameter of the ingot before the test, and D f is the fracture diameter of the ingot before the test.

8. A device for predicting surface cracks of a casting, characterized in that: include: An actual critical strain value module is used to determine the actual critical strain value according to the obtained experimental critical strain value and strain influence factor, wherein the strain influence factor includes a grain size factor, a component segregation factor and a notch factor; Critical strain rate module, used to determine the critical strain rate based on the acquired material properties, machine parameters and process conditions; The loss prediction module is used to generate a crack prediction result by using a damage integration method according to the actual critical strain value and the critical strain rate.

9. An electronic device, characterized in that: including memory and processor; The memory is used to store computer programs; The processor is used to implement the method for predicting surface cracks of a casting billet as described in any one of claims 1 to 7 when executing the computer program.

10. A computer-readable storage medium, characterized in that: The storage medium stores a computer program, and when the computer program is executed by a processor, the method for predicting surface cracks of a casting billet as described in any one of claims 1 to 7 is implemented.

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