Casting design optimization system for molding casting

Abstract

The invention relates to the technical field of casting design optimization, in particular to a casting design optimization system for forming casting. The system comprises the following modules: a fusion monitoring module, a flow simulation module, a deformation analysis module, a defect identification module and a process correction module. Wherein the melting monitoring module collects temperature distribution and mold filling parameters in the metal melting process, the flow simulation module deeply analyzes the flow characteristics of molten metal, and the deformation analysis module conducts mold filling solidification simulation based on metal flow and temperature data and determines the deformation condition in the forming process. The defect recognition module recognizes the stress concentration position of cast metal according to deformation and calibrates a cast defect area in combination with temperature distribution, and the process correction module adjusts process parameters according to the recognized defect area. According to the method, effective combination of data and the model is achieved, the stability and reliability of the integral casting process are improved by optimizing casting process parameters, and implementation of efficient casting production is promoted.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of casting design optimization, and particularly relates to a casting design optimization system for forming casting. BACKGROUND

[0002] The existing casting design optimization technology generally relies on traditional manual monitoring and empirical judgment, lacks real-time monitoring and accurate analysis of the metal melting process, and thus cannot recognize and adjust problems in time during the casting process, thereby causing frequent casting defects, affecting production efficiency and material utilization rate. The existing flow simulation technology is limited to the analysis of a single parameter and cannot comprehensively consider the interaction between temperature distribution and filling parameters, so it is difficult to fully reflect the flow of metal during the filling process, lacks an effective dynamic response mechanism, and thus reduces the prediction accuracy of deformation during forming, cannot realize real reproduction of the deformation process, and further causes unstable product quality, and the identification and positioning of casting defects are also restricted. SUMMARY

[0003] Therefore, it is necessary to provide a casting design optimization system for forming casting to solve at least one of the above technical problems.

[0004] To achieve the above-mentioned purpose, a casting design optimization system for forming casting, the system comprises the following modules: A melting monitoring module is configured to collect the temperature distribution of the metal melting process and the metal liquid filling parameter in real time. A flow simulation module is configured to analyze the metal flow condition in combination with the metal liquid filling parameter and the temperature distribution of the melting metal process. A deformation analysis module is configured to perform filling and solidification simulation through the metal flow condition and the temperature distribution of the melting metal process, and determine the deformation of the forming process according to the simulation filling and solidification model and the preset ideal solidification model. A defect identification module is configured to identify the stress concentration position of the casting metal according to the deformation of the forming process, and calibrate the casting defect area based on the stress concentration position and the temperature distribution of the melting metal process. A process correction module is configured to reverse the process parameter correction amount according to the casting defect area, and optimize the casting process parameter through the process parameter correction amount.

[0005] The present application realizes real-time monitoring of the melting state by the melting monitoring module which collects the temperature distribution and filling parameters of the metal melting process in real time, and provides accurate data support for subsequent analysis, improves the real-time monitoring ability of the melting state, and the flow simulation module effectively analyzes the flow of the metal liquid in combination with the temperature distribution and filling parameters, ensures that the flow characteristics are obtained in time during the filling process, and enhances the predictability of the forming process.

[0006] By analyzing the metal flow and temperature change, the simulation of filling and solidification is realized, the deformation in the forming process can be effectively identified, the forming result is ensured to meet the predetermined ideal model, the consistency of the cast product is improved, the stress concentration position in the cast metal is accurately identified by the defect identification module according to the deformation in the forming process, and a reliable basis is provided for subsequent positioning of defects, and the temperature distribution data is further calibrated to improve the accuracy and effectiveness of defect detection.

[0007] The process correction module corrects the reverse process parameters according to the identified defect area, optimizes the casting process parameters, improves the stability and reliability of the overall casting process, ensures that the quality of the final product is more consistent, and effectively combines data and models in multiple levels such as fluidity, deformation analysis and defect identification, provides a scientific and effective optimization path for casting design, promotes the technical progress and process innovation of the casting industry, and promotes the realization of efficient casting production, and finally improves the material utilization rate. BRIEF DESCRIPTION OF DRAWINGS

[0008] Fig. 1 A step flow chart of a casting design optimization system for forming casting is provided. Fig. 2 A schematic diagram of the metal liquid filling and solidification evolution process is provided. Fig. 3 A schematic diagram of the contact pressure and stress distribution of the metal liquid and the cavity wall is provided. The implementation, functional characteristics and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0009] The technical method of the present application will be described below in conjunction with the accompanying drawings, obviously, the described embodiments are part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0010] In addition, the accompanying drawings are included to provide a further understanding of the present application, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the present application and, together with the description, serve to explain the principles of the present application. In the drawings:

[0011] It is to be understood that, although terms such as "first", "second", and the like can be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element without departing from the scope of the example embodiments. The term "and / or" as used herein encompasses any and all combinations of one or more of the associated associated items.

[0012] To achieve the above object, there is provided Figs. 1 to 3 A casting design optimization system for forming casting, comprising a melting monitoring module, a flow simulation module, a deformation analysis module, a defect identification module and a process correction module, the casting design optimization system for forming casting performs the following steps: S1: collecting temperature distribution and metal liquid filling parameters of a metal melting process in real time; S2: analyzing metal flow conditions in combination with metal liquid filling parameters and temperature distribution of the melting metal process; S3: performing filling and solidification simulation through metal flow conditions and temperature distribution of the melting metal process, and determining deformation of the forming process according to the simulation filling and solidification model and a preset ideal solidification model; S4: identifying stress concentration positions of the casting metal according to the deformation of the forming process, and calibrating a casting defect area based on the stress concentration positions and the temperature distribution of the melting metal process; S5: inverting process parameter correction amount according to the casting defect area, and optimizing casting process parameters through the process parameter correction amount.

[0013] In this embodiment, the melting monitoring module runs on the main control unit of the casting device, which is used to collect the temperature distribution and metal liquid filling parameters in real time during the metal melting process. The system records the metal liquid surface temperature field in real time during the smelting stage through the multi-point infrared temperature array arranged above the molten pool. The temperature sampling frequency is set to 20 Hz, and the resolution can reach 0.5 Celsius degree. At the same time, a flow pulse sensor is installed at the inlet of the sprue to collect the metal liquid filling speed and filling pressure, so that the temperature distribution data and the metal liquid flow parameters can be sent to the subsequent module in the form of parallel data stream. The data buffer area is set as a sliding window of the last 10 seconds.

[0014] The flow simulation module is used to analyze the metal flow situation by combining the metal liquid filling parameters and the temperature distribution of the melting metal process. When the module starts, it receives the temperature distribution matrix and the parameter package of the metal liquid inlet speed and inlet pressure from the melting monitoring module. The inlet speed ranges from 0.3 meters per second to 1.1 meters per second. According to the temperature gradient change, different viscosity coefficients are set for each geometric unit. The internal flow solver is used to solve the flow path of the metal liquid in the sprue, the runner and the cavity step by step, and finally generate the metal flow field data frame. The data frame includes the corresponding relationship of the speed distribution, the local residence area and the temperature distribution.

[0015] The deformation analysis module is used to perform filling and solidification simulation by the metal flow situation and the temperature distribution of the melting metal process, and determine the deformation of the forming process according to the simulation filling and solidification model and the preset ideal solidification model. The module first constructs a three-dimensional filling and solidification model according to the speed distribution and temperature field generated by the flow simulation module. The model uses equidistant grid division method, and the unit size is fixed at 2 millimeters. Each grid unit records the data of temperature change, solidification start time and solidification end time, and deduces the solidification shrinkage trend based on these data, thereby forming the time sequence of the solidification process.

[0016] The defect recognition module is used to identify the stress concentration position of the cast metal according to the deformation of the forming process, and to mark the casting defect area based on the stress concentration position and the temperature distribution of the melting metal process. After receiving the deformation area marking diagram, the module maps the deformation data to the three-dimensional casting coordinate system, and judges whether there is a possible shrinkage defect position according to the local temperature drop rate. For example, when the local temperature drop rate is higher than 12 Celsius degrees per second and the deformation displacement is more than 0.7 millimeters, the area will be marked as a high-risk area of casting defects.

[0017] The process correction module is used to reverse the process parameter correction amount according to the casting defect area, and to optimize the casting process parameters through the process parameter correction amount. After receiving the defect area coordinates, the module will combine the defect distribution characteristics to reverse the corresponding process control amount adjustment direction. For example, if there are more shrinkage defects in a certain area, the module will suggest increasing the pouring temperature of the area by 15 to 25 degrees Celsius, and simultaneously adjusting the gate size or gate cross-sectional area to improve the flow rate of the molten metal entering the area.

[0018] Preferably, the flow simulation module analyzes the metal flow by combining the metal liquid filling parameters and the temperature distribution of the molten metal process, specifically: According to the temperature distribution of the molten metal process, the preset casting forming cavity is divided into multiple independent space units; Extract the molten metal flow rate and cavity pressure corresponding to the metal liquid filling parameters in each independent space unit; Determine the metal flow direction based on the cavity pressure and the cavity structure of the independent space unit; Map the metal flow situation by combining the metal flow direction and the molten metal flow rate.

[0019] In this embodiment, according to the temperature distribution of the molten metal process, the preset casting forming cavity is divided into multiple independent space units. In the embodiment, the type cavity of a typical casting can be divided into cubic units with a side length of 3 to 5 millimeters by using an equidistant grid division method. Each unit stores the temperature value, geometric boundary, and adjacent unit index of its corresponding area, so that subsequent flow calculation can be performed by traversing and solving each unit according to a fixed space granularity. The temperature data comes from the real-time temperature matrix of the pre-acquisition module, and the data refresh frequency is maintained in the range of 15 to 30 Hz.

[0020] It needs to be explained that after division, the independent space unit not only stores temperature data, but also assigns an initial flow state label to each unit. This label is used to mark whether the unit is in the first contact state with the metal liquid. For example, after pouring starts, the grid units through which the front metal liquid flows are marked as "active" state, while the units not contacted by the metal liquid remain in "idle" state.

[0021] Specifically, after division, the module extracts the molten metal flow rate and cavity pressure corresponding to the metal liquid filling parameters in each independent space unit. The flow rate data comes from the online flow sensor at the gate inlet, such as in a typical test, the inlet flow rate ranges from 0.4 to 0.9 meters per second. At the same time, the cavity pressure is indirectly calculated by the strain gauge arranged on the outer wall of the cavity. For example, the inlet pressure can reach 18 to 25 kilopascals.

[0022] Further, after the flow rate and cavity pressure data are loaded, the module determines the metal flow direction based on the cavity pressure and the cavity structure of the individual space unit. The flow direction determination process is based on the pressure gradient and the geometric connection relationship between adjacent units. For example, when the local pressure of a unit is higher than that of its downstream unit by more than 3 kPa, the flow direction of the unit is determined to be directed to the downstream unit. Meanwhile, if there is an elongated structure between a unit and its adjacent unit with an aspect ratio greater than 3:1, the direction is recorded as the main flow channel.

[0023] Further, by mapping the metal flow direction and the molten metal flow rate, the module performs flow rate superposition and direction matching processing on all units in the "active" state. For example, if the main direction of a unit is directed to the east unit and its flow rate data is 0.7 m / s, the unit is recorded as flowing east in the simulated flow field and advancing to the adjacent unit at the next time. Meanwhile, the module records the flow time node of each unit, such as 0.1 s, 0.2 s, and 0.5 s, to form a continuous metal flow trajectory data set.

[0024] Preferably, the metal liquid mold filling and solidification evolution data is calculated based on the metal flow situation and the temperature distribution of the molten metal process, specifically as follows: determining a first cavity pressure change value in the casting forming cavity based on the metal flow situation; obtaining a second cavity pressure change value by fusing the influence of the temperature distribution of the molten metal process on the first cavity pressure change value; calculating metal liquid mold filling and solidification evolution data based on the second cavity pressure change value and the temperature distribution of the molten metal process; performing mold filling and solidification simulation based on the metal liquid mold filling and solidification evolution data to generate a simulated mold filling and solidification model; comparing the simulated mold filling and solidification model with a preset ideal solidification model to identify model structure differences; determining the deformation of the forming process based on the model structure differences.

[0025] In this embodiment, the first cavity pressure change value in the casting forming cavity is determined based on the metal flow situation. In actual application, the flow rate distribution and pressure distribution output by the aforementioned flow simulation module can be used to obtain the local pressure change trajectory over time of each space unit in the cavity. For example, in a typical steel casting working condition, the inlet pressure can be around 20 kPa, and after flowing through the elongated cavity area, it can drop to the range of 12 kPa to 15 kPa. This pressure change is recorded as the first cavity pressure change value sequence.

[0026] It needs to be explained that the first cavity gas pressure change value is not only based on the indirect measurement results of the pressure sensor, but also needs to be combined with the pressure compensation amount of the local flow resistance position in the flow path. In actual operation, the corner position with obvious flow resistance will be added with a compensation value of 0.5 kPa to 1.3 kPa to reflect the actual action pressure of the molten metal.

[0027] Specifically, after obtaining the first cavity gas pressure change value, the system will fuse the influence of the temperature distribution of the molten metal process on the gas pressure change value to obtain the second cavity gas pressure change value. In this process, the system will read the temperature matrix from the temperature monitoring module, for example, the inlet temperature is generally 700-740 degrees Celsius, and the temperature at the end of the cavity region decreases to 640-660 degrees Celsius due to heat dissipation. The module adds a thermal expansion compensation amount to the gas pressure change value based on these temperature differences, for example, when the temperature of a certain unit is lower than 680 degrees Celsius, a pressure correction value less than 0.8 kPa is introduced, so as to obtain the second cavity gas pressure change value closer to the real solidification process.

[0028] Further, please refer to Fig. 2 , the system accumulates and calculates the metal liquid filling and solidification evolution data based on the second cavity gas pressure change value and the temperature distribution of the molten metal process. In actual processing, the module will construct a temperature decreasing curve and a pressure changing curve for each space unit, for example, the temperature decreasing curve usually records a decrease of 8-15 degrees Celsius per second, and the pressure changing curve combines the second cavity gas pressure change value and accumulates and superimposes in time sequence with a step of 20 milliseconds. Finally, the corresponding solidification start time, solidification end time and solidification shrinkage trend data for each unit are generated, which will constitute the metal liquid filling and solidification evolution data.

[0029] Further, according to the metal liquid filling and solidification evolution data, a filling and solidification simulation is carried out to generate a simulation filling and solidification model. In the simulation stage, the system will calculate the corresponding solid-liquid phase ratio based on the solidification time and temperature decreasing curve of each unit and reconstruct the three-dimensional solidification volume. In a typical test, a casting with a size of 150x80x40 mm will be divided into about 400,000-600,000 voxels. The system records the solidification evolution stage for each voxel and generates the final simulation filling and solidification model.

[0030] It needs to be explained that the simulation filling and solidification model will be subjected to a whole smoothing process before being finally generated, so as to eliminate the local abnormal solidification data caused by temperature sampling jitter. The smoothing process adopts a neighborhood voxel average strategy, usually taking a three-by-three-by-three voxel as a neighborhood range, and performing an average processing on the solidification start time and solidification shrinkage amount in the neighborhood.

[0031] Meanwhile, the simulation solidification model is compared with the preset ideal solidification model to identify the structural difference of the model. In the implementation, the system will call the ideal model matching the type of the casting from the process database. The ideal model is usually formed based on the standardized process conditions, for example, the solidification volume error of a certain key part under standard conditions should be less than 0.9 millimeters. When the solidification volume deviation of a certain area in the simulation model exceeds 1.2 millimeters, the system will identify the area as a structural difference point.

[0032] Further, the deformation of the forming process is determined by the structural difference of the model. In this stage, the system will remap the difference voxels to the actual geometric area according to the casting coordinate system, for example, sampling at an interval of 1 millimeter for thin-walled sections and sampling at an interval of 3 millimeters for thick-walled sections, and estimating the local structural deformation according to the deviation of the difference voxels.

[0033] Preferably, the first cavity gas pressure change value in the casting forming cavity is determined by the metal flow condition, specifically: The leading position of the metal liquid filling is identified according to the metal flow condition; The gas space in the casting forming cavity that is not occupied by the metal liquid is determined before the leading position of the metal liquid filling; The volume compression rate of the gas space is calculated according to the moving speed of the leading position; The first cavity gas pressure change value is determined based on the volume compression rate.

[0034] In this embodiment, the leading position of the metal liquid filling is identified according to the metal flow condition. In the specific operation, the system reads the metal liquid flow rate matrix and flow direction matrix output from the flow simulation module, for example, for a cast steel part with a pouring flow rate of 0.5 meters per second to 0.8 meters per second, the system tracks the advancing path of the metal liquid in the cavity at a refresh interval of 20 milliseconds, thereby determining the spatial unit position of the leading edge at each time node.

[0035] It needs to be explained that the leading position not only refers to the unit first contacted by the metal liquid, but also includes the edge unit that slows down locally due to the influence of temperature gradient, for example, when the local temperature is lower than 680 degrees Celsius, the metal liquid flow rate will decrease to about 0.3 meters per second.

[0036] Specifically, after identifying the leading position, the system determines the gas space in the casting cavity that is not occupied by the molten metal before the leading position of the molten metal filling, and in actual processing, the system combines the space units not marked as "active" by the molten metal into continuous gas blocks based on the connectivity relationship, for example, for a typical cavity, the remaining space accounts for about 12% to 18% of the total volume, and the system marks this area as a gas space area, and the volume of this area is accumulated by multiplying the unit volume by the number of units, for example, the remaining gas volume at this stage may be about 6500 cubic millimeters to 9000 cubic millimeters.

[0037] Further, the system calculates the volume compression rate of the gas space according to the moving speed of the leading position, and in this stage, the module reads the displacement difference between any two time points from the leading track, for example, the leading position may move 2 millimeters to 3 millimeters during 0.1 seconds to 0.12 seconds, and the advancing speed is about 0.1 meters per second to 0.15 meters per second, and the system estimates the volume increment of the space occupied by the molten metal according to the speed and the local geometry of the cavity, for example, at the above speed, the molten metal will occupy about 80 cubic millimeters to 120 cubic millimeters of space in the corresponding time period, so as to obtain the gas space reduction rate and further convert it into the volume compression rate.

[0038] Further, the compression rate is combined with the current remaining gas space to obtain the gas compression trend, and the transient gas pressure change is recorded according to the compression amount of each update period, for example, when the compression rate is 5 cubic millimeters per millisecond and the remaining gas space is about 7000 cubic millimeters at a certain time, the system records the gas pressure rising trend at this time as a fast rising state, and maps this state as a record point in the gas pressure change value sequence.

[0039] Preferably, the temperature distribution of the molten metal process is fused to affect the first cavity gas pressure change value, and the second cavity gas pressure change value is obtained, specifically: extracting the temperature distribution of the gas space area from the temperature distribution of the molten metal process; calculating the temperature change amount of the gas in the gas space according to the temperature distribution; calculating the thermal expansion volume change of the gas based on the temperature change amount; superimposing the thermal expansion volume change on the first cavity gas pressure change value to obtain the second cavity gas pressure change value.

[0040] In this embodiment, the influence of the temperature distribution of the molten metal process on the first cavity gas pressure change value is obtained by gradually analyzing the temperature state of the gas space and superimposing the thermal expansion effect, wherein the temperature data is collected from the thermocouple array inside the casting forming cavity, and the system collection frequency is set to 2Hz to ensure the continuity of the temperature distribution over time, so as to accurately obtain the temperature distribution data of the gas space region.

[0041] Specifically, when extracting the temperature distribution of the gas space region from the temperature distribution of the molten metal process, the casting forming cavity is divided into a plurality of three-dimensional grid units, the side length of each grid unit is set to 2mm, the grid units not covered by the metal liquid are screened, and the corresponding temperature sensor readings are called to form the temperature distribution data of the gas space region, for example, the temperature range of the gas space region at a certain moment is 85℃ to 145℃.

[0042] Further, when calculating the temperature change of the gas in the gas space according to the temperature distribution, the temperature change of each grid unit is calculated by comparing the current temperature distribution of the gas space region with the initial temperature reference value, for example, the initial temperature is 25℃, for example, the temperature of a certain grid unit rises from 25℃ to 120℃, and the temperature change of the grid unit is 95℃, and the temperature change of all grid units is formed into structured data.

[0043] In a more specific implementation process, when calculating the thermal expansion volume change of the gas based on the temperature change, the temperature change of each grid unit is input into the thermal expansion calculation module, and the module adopts a fixed parameter air thermal expansion rate, which can be set to ℃, so as to obtain the corresponding volume change of each grid unit, for example, the volume change of a certain unit when rising by 95℃ can be recorded as , and the volume changes of all units are accumulated to generate total thermal expansion volume change data.

[0044] Further, when superimposing the thermal expansion volume change on the first cavity gas pressure change value, the total thermal expansion volume change and the volume change corresponding to the first cavity gas pressure change value are compared, and the two are linearly superimposed to obtain the second cavity gas pressure change value, for example, the volume change corresponding to the first cavity gas pressure change is , the total thermal expansion volume change is , and the volume change corresponding to the superimposed second cavity gas pressure change value is .

[0045] Preferably, the second cavity gas pressure change value is combined with the temperature distribution of the molten metal process to accumulate and calculate the metal liquid filling and solidification evolution data, which is specifically: determining the gas pressure load distribution acting on the surface of the molten metal according to the second cavity gas pressure change value; extracting the temperature state data of the molten metal from the temperature distribution of the molten metal process; determining the response characteristics of the molten metal according to the temperature state data and the molten metal filling parameters; calculating the deformation response of the molten metal based on the gas pressure load distribution and the response characteristics; superimposing the deformation response of the molten metal each time to generate the molten metal filling and solidification evolution data.

[0046] In this embodiment, the process of accumulating and calculating the molten metal filling and solidification evolution data by combining the second cavity gas pressure change value with the temperature distribution of the molten metal process is obtained by gradually superimposing the local deformation response of the molten metal under the conditions of loading and temperature rise, wherein the second cavity gas pressure change value comes from the superimposed gas pressure analysis result of the previous step, for example, the volume change corresponding to the second cavity gas pressure change value is 1.523 cm³, and the gas pressure load data acting on the surface of the molten metal is obtained through numerical conversion.

[0047] Specifically, when determining the gas pressure load distribution acting on the surface of the molten metal according to the second cavity gas pressure change value, the casting forming cavity is divided into a plurality of surface grid units, the area of each grid unit is set to , and the second cavity gas pressure change value is distributed to each grid unit according to the volume change ratio, thereby generating the gas pressure load distribution, for example, the load value of part of the front edge grid unit can reach 2.1 kPa, and the load of the grid unit far away from the front edge region is 1.6 kPa.

[0048] Further, when extracting the temperature state data of the molten metal from the temperature distribution of the molten metal process, the data points of the internal temperature sensor of the molten metal are collected in real time and are interpolated according to the three-dimensional grid, so that there is corresponding temperature state information at each position in the molten metal, for example, the temperature of the center region of the molten metal is 680℃ at a certain moment, and the temperature near the wall region is about 615℃.

[0049] In a more specific implementation, when determining the response characteristics of the molten metal according to the temperature state data and the molten metal filling parameters, the temperature state and the molten metal physical property table are corresponded, for example, the flowability parameter corresponding to 680℃ is defined as a high flow zone, and the flowability parameter corresponding to 615℃ is defined as a medium flow zone, and the temperature attribute and the flowability attribute form a data set by combining the filling speed parameter, for example, 0.34 m per second.

[0050] Further, when calculating the deformation response of the metal liquid based on the gas pressure load distribution and the response characteristics, the aforementioned two data sets are input into the deformation analysis module, and iterative operation is performed at a time step of 0.02 seconds, so as to obtain the local deformation variable of the metal liquid at each position, for example, the local deformation variable in the high-flow area can reach 0.45 mm, and the local deformation variable in the medium-flow area is only 0.21 mm.

[0051] Further, when superimposing the deformation response of the metal liquid each time to generate the metal liquid filling and solidification evolution data, the deformation sequence of continuous time is combined into a complete solidification evolution data set by recording the deformation of all grid elements at each time step and performing cumulative operation, for example, a complete deformation record set representing the filling to the initial solidification stage can be obtained after 50 time steps are accumulated.

[0052] Especially important is that the gas pressure load distribution acting on the surface of the metal liquid is determined according to the second cavity gas pressure change value, and specifically is: According to the metal flow condition, the contact interface range between the metal liquid and the gas space is identified; The local gas pressure value in the second cavity gas pressure change value is extracted in the contact interface range; The pressure difference value between the local gas pressure value and the preset initial ambient pressure is calculated; The gas pressure load distribution is identified based on the pressure difference value and the contact interface range.

[0053] In the embodiment, the process of determining the gas pressure load distribution acting on the surface of the metal liquid according to the second cavity gas pressure change value is realized by interface identification and gas pressure difference calculation, the contact interface between the gas space and the metal liquid is accurately divided, and the local gas pressure data is extracted, so as to establish a load distribution model acting on the surface of the metal liquid in a multi-dimensional space range.

[0054] Specifically, when the contact interface range between the metal liquid and the gas space is identified according to the metal flow condition, first, infrared thermal imaging sensing units and high-speed visual detection devices are arranged in the casting forming cavity to monitor the filling boundary dynamics of the metal liquid, under the condition that the system sampling frequency is 200 frames per second, the contact line between the gas space and the metal liquid is extracted as three-dimensional point cloud data by detecting the temperature mutation zone and the optical reflection interface of the metal liquid front, and a contact interface range model is formed by using a voxel reconstruction algorithm.

[0055] Further, when extracting the local gas pressure value in the second cavity gas pressure change value in the contact interface range, the data of the micro-pressure sensor array arranged at the top, side wall and bottom of the cavity is synchronously read, the range of the sensor is 0-5 kPa, the sampling interval is 0.01 seconds, the transient gas pressure value of each measuring point is mapped with the interface grid node, so that each interface grid element corresponds to a local gas pressure value, for example, the node gas pressure value near the metal liquid front region is 2.3 kPa, and the gas pressure value far from the front is 1.9 kPa.

[0056] It needs to be explained that in order to obtain the real pressure gradient acting on the surface of the metal liquid, the local gas pressure value needs to be corrected to eliminate the influence of the environmental base pressure. Specifically, when calculating the pressure difference value between the local gas pressure value and the preset initial environmental pressure, the initial environmental pressure in the laboratory is set to , and the local pressure difference distribution matrix is calculated by data difference processing, wherein part of the high difference value area reflects the physical characteristics that the gas is rapidly compressed by the metal liquid front.

[0057] Further, based on the pressure difference value and the contact interface range to identify the gas pressure load distribution, the foregoing pressure difference distribution matrix is fused with the three-dimensional contact interface model to generate a multi-layer pressure load diagram. The load intensity is displayed in color scale in three-dimensional space, so as to obtain a complete gas pressure load distribution data set, for example, the load value near the sprue reaches 2.4 kPa, and near the exhaust passage is only 1.7 kPa.

[0058] Preferably, the deformation response of the metal liquid is calculated based on the gas pressure load distribution and the response characteristics, specifically: determine the change of the gas pressure load distribution based on the temperature distribution of the molten metal process, so as to obtain the change gas pressure value; calculate the gas pressure stress of the metal liquid under the change gas pressure value; determine the deformation stress threshold under the temperature distribution of the molten metal process according to the response characteristics; identify the stress area whose stress exceeds the deformation stress threshold in the gas pressure stress, and mark it as the metal deformation area; superimpose the metal deformation area, so as to map the deformation response of the metal liquid.

[0059] In this embodiment, the process of calculating the deformation response of the metal liquid based on the gas pressure load distribution and the response characteristics is completed by comprehensive analysis of the gas pressure change, the temperature distribution and the stress threshold. The gas pressure dynamic change is matched with the flow viscosity characteristics of the metal liquid at different temperature intervals to form the space-time response mapping of the force and deformation of the metal liquid, so as to realize the calculation basis of the pre-solidification shape change.

[0060] Specifically, when determining the change of the gas pressure load distribution based on the temperature distribution of the molten metal process, the temperature sensor data arranged at different height positions of the molding cavity is collected in real time, the temperature sampling interval is 0.1 seconds, the sensor measurement range is 400°C to 900°C, and the previous stage of the gas pressure load distribution map is updated synchronously, the difference in gas pressure distribution caused by temperature change is calculated as the change of the gas pressure value, for example, when the temperature at the upper part of the cavity rises to 720°C, the local gas pressure value increases by about 0.2kPa compared with the initial load, thereby forming a change of the gas pressure data set.

[0061] Further, when calculating the gas pressure stress of the molten metal under the change of the gas pressure value, the change of the gas pressure value is mapped to the three-dimensional grid model of the molten metal surface, the area of each unit is set to , the stress distribution map is formed by calculating the gas pressure action intensity of each unit through the distribution of the load data, for example, the average gas pressure stress in the central area of the molten metal is 2.6kPa, and the average gas pressure stress in the edge area is 1.9kPa.

[0062] It needs to be explained that in order to determine the actual deformation trend of the molten metal, the response characteristic parameters should be introduced under the same temperature environment, the deformation stress threshold under the temperature distribution of the molten metal process is determined according to the response characteristics, the viscosity characteristics and yield strength data corresponding to different temperature intervals are selected, for example, the deformation stress threshold under the condition of 680°C is set to 1.5kPa, and the deformation stress threshold under the condition of 640°C is set to 2.3kPa.

[0063] Further, when identifying the stress area whose stress exceeds the deformation stress threshold in the gas pressure stress and marking it as the metal deformation area, the stress distribution map is compared with the threshold mapping table at the pixel level, and all grids whose stress value is higher than the corresponding threshold are marked, for example, a continuous high stress concentration band with a length of about 8mm and a width of about 3mm is formed in the middle of the cavity, and the band-shaped area is defined as the main deformation area.

[0064] Specifically, when superimposing the metal deformation area to map the deformation response of the molten metal, the deformation area data of the continuous time step is spatially superimposed, the time step is set to 0.05 seconds, thereby generating a complete three-dimensional deformation response image, which contains the morphological change data of the molten metal in the whole filling to the initial stage of solidification, for example, the cumulative deformation volume of the molten metal in the first 10 seconds after pouring is completed is about .

[0065] Preferably, the stress distribution generated by the gas pressure according to the gas pressure load distribution is specifically: identifying the molten metal surface area affected by the gas pressure according to the gas pressure load distribution; calculating the surface area value of the molten metal surface area; The local air pressure value in the air pressure load distribution is multiplied by the corresponding surface area value to obtain the air pressure force at each position. The stress distribution is identified according to the transmission direction of the air pressure force inside the molten metal.

[0066] In this embodiment, the process of calculating the stress distribution generated by the air pressure according to the air pressure load distribution is realized by identifying the compressed area of the molten metal surface, calculating the load force, and deducing the internal stress propagation path. It needs to be explained that the core of this process is to convert the surface air pressure distribution information into the stress response field inside the molten metal to build a real physical model reflecting the influence of gas compression on molten metal.

[0067] Specifically, when identifying the molten metal surface area affected by air pressure according to the air pressure load distribution, the previously generated three-dimensional air pressure load distribution dataset is used to divide the molten metal surface in the casting forming cavity into a plurality of regular grid units, and the area of each unit is The grid units with air pressure value higher than 1.5kPa are identified by threshold screening, and these units are defined as the main compressed area. For example, about 320 high-load units are identified near the sprue area, and the total surface area is about The molten metal surface compressed area model is formed.

[0068] Further, when calculating the surface area value of the molten metal surface area, the grid unit area and quantity are cumulatively counted, and the total area value of the entire compressed surface is calculated by spatial integration. In the above example, the total surface area is about At the same time, each local sub-area is grouped and labeled to match the corresponding relationship in the subsequent calculation. This area value is used to determine the spatial weight of the load distribution.

[0069] It needs to be explained that the combination of surface area and air pressure determines the strength of local air pressure force. Specifically, when multiplying the local air pressure value in the air pressure load distribution by the corresponding surface area value, the point multiplication operation is performed on each grid unit to obtain the unit load force value. For example, in the area with air pressure value of 2.0kPa and unit area of 1.2mm², the local air pressure force is calculated as 2.4N. All unit load values are cumulatively formed into an air pressure force distribution diagram.

[0070] Further, when identifying the stress distribution according to the transmission direction of the air pressure force inside the molten metal, the air pressure force vector is projected along the normal direction into the grid structure inside the molten metal, and the force transmission path direction is adjusted according to the temperature gradient field inside the molten metal. The stress value of the internal node is calculated by layer-by-layer expansion to form a stress distribution matrix. For example, the average stress of the node near the surface is 2.3kPa, and the stress decays to 1.1kPa at a depth of 2mm from the surface, so that a complete air pressure stress distribution model is obtained.

[0071] Preferably, identifying the stress distribution according to the transmission direction of the gas pressure force inside the molten metal specifically comprises: identifying the direction of action of the gas pressure force to obtain a normal direction perpendicular to the surface area of the molten metal; tracking the stress transmission path inside the molten metal along the normal direction; calculating the stress attenuation amount according to the length of the stress transmission path; subtracting the stress attenuation amount from the gas pressure force to generate the stress value at each position inside the molten metal; integrating the stress values at each position inside the molten metal into a stress distribution.

[0072] In this embodiment, the stress distribution data is obtained by identifying the transmission direction of the gas pressure force inside the molten metal. A gas pressure sensor array is arranged at the top of the casting mold cavity, the sensitivity of the sensor is set to 0.01 MPa, and the sampling frequency is 100 Hz. After the pressure signals collected by the array are subjected to noise suppression by a digital filtering module, the spatial distribution information of the gas pressure on the surface of the molten metal is extracted, and the average gas pressure acting strength in the vertical direction is calculated according to the surface normal component. The normal direction perpendicular to the surface of the molten metal is determined as the reference vector.

[0073] Specifically, to track the stress transmission path of the gas pressure inside the molten metal along the normal direction, a three-dimensional finite element grid structure needs to be established on the casting mold section, the unit size is set to 0.5 mm x 0.5 mm x 0.5 mm, the stress transmission coefficient of each unit is calculated using the displacement gradient between nodes, and the stress transmission is recorded in steps of 1 mm per layer depth during the path tracking process. The local stress attenuation rate is calculated by the stress change rate of adjacent nodes in the path, and the stress change curve of each path is integrated to obtain the stress attenuation amount along the transmission path.

[0074] It should be explained that the stress attenuation amount reflects the proportion of the gas pressure consumed in the molten metal, so the actual stress value of each node inside the molten metal is obtained by subtracting the corresponding attenuation value from the initial gas pressure force.

[0075] Specifically, this calculation process is executed in parallel on all nodes of the three-dimensional grid, the operation efficiency is improved by matrix calculation, and after the stress value is generated, the full-field nodes are subjected to interpolation fitting to construct a continuous stress distribution field inside the molten metal, and the stress distribution field data is output.

[0076] Preferably, the filling and solidification simulation according to the filling and solidification evolution data of the molten metal specifically comprises: extracting the filling front advancing speed in the filling and solidification evolution data of the molten metal, and determining the solidification interface advancing curve; According to the solidification interface advancing curve, the contact pressure sequence of the metal liquid and the cavity wall surface is analyzed; According to the contact pressure sequence of the metal liquid and the cavity wall surface, the numerical value of the local volume distribution of the metal liquid entering each region of the cavity is corrected, and a three-dimensional temperature-pressure coupling field is built in combination with the temperature distribution; Through the three-dimensional temperature-pressure coupling field in combination with the metal liquid filling and solidification evolution data, a simulation filling and solidification model is built.

[0077] In this embodiment, please refer to Fig. 2 The metal liquid filling and solidification evolution data are analyzed and reconstructed, a simulation filling and solidification model which can be used to truly reproduce the casting process is established, and the multi-field coupling calculation of temperature, pressure and flow state is realized. The metal liquid filling evolution data are extracted from the filling process monitoring module, which includes the advancing rate data of the metal liquid flow front and the temperature gradient sequence. The sampling frequency of the advancing rate is set to 50 Hz, and the spatial resolution is 1 mm. The solidification interface advancing curve is fitted by using the data, and the spatial position change curve of the interface at different time steps is obtained by using the spline interpolation method.

[0078] Specifically, after obtaining the solidification interface advancing curve, the contact pressure sequence of the metal liquid and the cavity wall surface is analyzed according to the change trend of the interface curve. The pressure of the wall surface at different positions is measured by using a pressure sensor array, the sampling interval is 0.02 seconds, the pressure sequence of each point is time-aligned, the wall surface stress change rate is calculated by using the difference method, and thus the dynamic distribution data set of the metal liquid contact pressure is constructed. The high stress area and the low stress buffer zone are identified by using the pressure sequence.

[0079] It should be explained that the contact pressure has a significant influence on the volume distribution of the metal liquid flowing into each region, and therefore the local volume distribution coefficient needs to be corrected according to the pressure sequence data.

[0080] Specifically, for each unit of the cavity grid division, the flow volume distribution value is corrected by using the pressure gradient and the local temperature difference, the corrected data is input into the temperature field calculation module, the transient temperature distribution of each node is obtained by solving the heat conduction equation, and the three-dimensional temperature-pressure coupling field model is established by superimposing the temperature distribution and the corrected pressure field.

[0081] Further, after the three-dimensional temperature-pressure coupling field is established, it is fused with the filling and solidification evolution data, the flow tracking algorithm based on volume capture (VOF) is used to simulate the flow and solidification process of the metal liquid in different regions, the model grid size is 0.5 mm, the boundary conditions include the constant temperature of the mold outer wall of 300 K and the initial temperature of the metal liquid of 1450 K, and in the calculation process, the explicit solution method with 100 iteration steps is used. The metal liquid solidification front morphology, temperature gradient change and volume fraction distribution data are output by simulation.

[0082] Especially important is that according to the solidification interface advancing curve, the contact pressure sequence of the metal liquid and the cavity wall surface is analyzed specifically as follows: The first contact of the cavity wall surface and the metal liquid in the casting forming is identified through the solidification interface advancing curve, and the contact area change of the metal liquid and the cavity wall surface is determined according to the deformation response of the metal liquid in the metal liquid filling and solidification evolution data; The contact pressure change data is calculated based on the contact area change of the metal liquid and the cavity wall surface; All the contact pressure change data is combined to be converted into the contact pressure sequence of the metal liquid and the cavity wall surface.

[0083] In this embodiment, referring to Fig. 3 , the contact pressure change rule of the metal liquid and the cavity wall surface is determined by using the solidification interface advancing curve, so as to generate the contact pressure sequence which can be used for simulation calculation. In the filling and solidification monitoring system, the solidification interface advancing curve data is introduced, the curve is recorded with a time step of 0.05 seconds, and the spatial resolution is set to 1 mm. The first contact time of the metal liquid and the cavity wall surface is identified by calculating the intersection position of the curve and the cavity geometric surface, the time is taken as the starting point of the pressure response, and the corresponding local flow velocity and deformation response parameters in the metal liquid filling and solidification evolution data are extracted.

[0084] Specifically, after the contact starting point is identified, the contact area change data of the metal liquid flow boundary and the cavity wall surface is determined according to the deformation degree of the metal liquid flow boundary. The metal liquid outer contour shape is obtained through the high-temperature visual monitoring module, the contact boundary length at each time is calculated by using the frame-by-frame edge extraction algorithm, and the contact area change value is obtained by combining the cavity wall surface geometric curvature. The time resolution of the contact area calculation is kept at the level of 20 milliseconds, and these area change values are mapped into the time sequence to reflect the dynamic contact relationship between the metal liquid and the cavity.

[0085] It needs to be explained that the contact area change directly affects the change trend of the contact pressure, so the contact pressure change data, namely “Arpressure”, needs to be calculated based on the contact area change data of the metal liquid and the cavity wall surface. The average contact pressure acting on the unit area is obtained by multiplying the contact area of each time step and the corresponding metal liquid inner surface stress value, and the continuous contact pressure change curve is obtained by numerical integration.

[0086] Further, after the contact pressure change data at each time is obtained, the pressure curves of different wall surface regions are aligned along the time axis to form a multi-region synchronous data set. Through data interpolation and weighted average processing, the pressure changes of each region are integrated into the complete contact pressure sequence of the metal liquid and the cavity wall surface. The pressure sequence takes the time step as the main sequence variable and contains the pressure amplitude information of different spatial positions.

[0087] Thus, the embodiments should be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the description given above, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.

[0088] The foregoing is considered as illustrative only of the principles of the application. Numerous modifications and changes will readily occur to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Therefore, the application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A casting design optimization system for molding casting, characterized in that, Includes the following modules: The melting monitoring module is used to collect the temperature distribution and molten metal filling parameters during the metal melting process in real time. The flow simulation module is used to analyze metal flow by combining the filling parameters of molten metal and the temperature distribution during the molten metal process. The deformation analysis module is used to simulate the filling and solidification process by observing the metal flow and the temperature distribution during the molten metal process, and to determine the deformation during the forming process based on the simulated filling and solidification model and the preset ideal solidification model. The defect identification module is used to identify the stress concentration location of the cast metal based on the deformation during the forming process, and to mark the casting defect area based on the stress concentration location and the temperature distribution during the molten metal process. The process correction module is used to invert the process parameter correction amount based on the casting defect area, and optimize the casting process parameters through the process parameter correction amount.

2. The casting design optimization system for molding casting according to claim 1, characterized in that, The flow simulation module analyzes metal flow by combining molten metal filling parameters and temperature distribution during the molten metal process. The pre-designed casting cavity is divided into multiple independent spatial units based on the temperature distribution during the molten metal process; Extract the molten metal flow rate and cavity pressure corresponding to the molten metal filling parameters in each independent spatial unit; The direction of metal flow is determined by the cavity pressure and the cavity structure of the independent spatial units; The metal flow pattern is mapped by combining the direction of metal flow with the velocity of molten metal.

3. The casting design optimization system for molding casting according to claim 1, characterized in that, The deformation analysis module calculates the solidification evolution data of molten metal by accumulating the metal flow and temperature distribution during the molten metal process. The pressure change value of the first cavity in the casting molding cavity is determined by the metal flow. The influence of temperature distribution during the fusion molten metal process on the gas pressure change value of the first cavity was investigated, and the gas pressure change value of the second cavity was obtained. The evolution data of molten metal filling solidification was calculated by combining the pressure change value of the second cavity with the temperature distribution during the molten metal process; Based on the solidification evolution data of molten metal, a solidification simulation was performed to generate a simulated solidification model. By comparing the simulated filling and solidification model with the preset ideal solidification model, the structural differences between the models can be identified. Deformation during the molding process is determined by differences in model structure.

4. The casting design optimization system for molding casting according to claim 3, characterized in that, The specific value of the gas pressure change in the first cavity of the casting molding cavity is determined by the metal flow: Identify the leading edge of the molten metal filling based on the metal flow pattern; Determine the gas space in the casting cavity that is not occupied by the molten metal before the leading edge of the molten metal filling. The volume compression rate of the gas space is calculated based on the moving speed of the leading edge position; The pressure change value of the first cavity is determined based on the volume compression rate.

5. The casting design optimization system for molding casting according to claim 3, characterized in that, The influence of temperature distribution during the molten metal fusion process on the pressure change in the first cavity was investigated, and the pressure change in the second cavity was obtained as follows: Extracting the temperature distribution of the gas space region from the temperature distribution during the molten metal process; Calculate the temperature change of the gas in the gas space based on the temperature distribution; Calculate the thermal expansion volume change of a gas based on temperature changes; The thermal expansion volume change is superimposed on the first cavity pressure change value to obtain the second cavity pressure change value.

6. The casting design optimization system for molding casting according to claim 3, characterized in that, The specific calculation of the solidification evolution data of molten metal filling mold, which combines the pressure change value of the second cavity with the temperature distribution during the molten metal process, is as follows: The distribution of pressure load acting on the surface of the molten metal is determined based on the pressure change value of the second cavity. Extracting temperature state data of molten metal from the temperature distribution during the molten metal process; The response characteristics of the molten metal are determined based on temperature status data and molten metal filling parameters. The deformation response of molten metal is calculated based on the distribution and response characteristics of the gas pressure load. The deformation response of each molten metal is superimposed to generate molten metal filling and solidification evolution data.

7. The casting design optimization system for molding casting according to claim 6, characterized in that, The deformation response of the molten metal is calculated based on the gas pressure load distribution and response characteristics as follows: The change in pressure load distribution is determined based on the temperature distribution during the molten metal process, thereby obtaining the change in pressure value; Calculate the pressure stress on the molten metal under varying pressure values; The deformation stress threshold under the temperature distribution during the molten metal process is determined based on the response characteristics; In pneumatic stress, identify stress regions where the stress exceeds the deformation stress threshold and mark them as metal deformation regions; By superimposing the deformed regions of the metal, the deformation response of the molten metal is mapped.

8. The casting design optimization system for molding casting according to claim 7, characterized in that, The stress distribution generated by air pressure is calculated based on the air pressure load distribution as follows: Identify the metal liquid surface region affected by air pressure based on the air pressure load distribution; Calculate the surface area of ​​the molten metal surface region; Multiply the local air pressure value in the air pressure load distribution with the corresponding surface area value to obtain the air pressure force at each location; The stress distribution can be identified by the direction of transmission of air pressure force inside the molten metal.

9. The casting design optimization system for molding casting according to claim 8, characterized in that, The stress distribution is identified based on the direction of transmission of air pressure force within the molten metal. Identify the direction of the air pressure force to obtain the normal direction perpendicular to the surface area of ​​the molten metal; Tracing the stress transfer path inside the molten metal along the normal direction; Calculate the stress attenuation based on the length of the stress transmission path; Subtract the stress attenuation from the air pressure force to generate the stress value at each location inside the molten metal. The stress values ​​at various locations inside the molten metal are integrated into a stress distribution.

10. The casting design optimization system for molding casting according to claim 3, characterized in that, The specific steps for performing filling and solidification simulation based on molten metal filling and solidification evolution data are as follows: Extract the advancement rate of the filling front from the solidification evolution data of molten metal and determine the advancement curve of the solidification interface; The contact pressure sequence between the molten metal and the cavity wall was analyzed based on the solidification interface propagation curve. The values ​​of the local volume distribution of the molten metal in each region of the cavity are corrected based on the pressure sequence of the contact action between the molten metal and the cavity wall, and a three-dimensional temperature-pressure coupling field is constructed in combination with the temperature distribution. A simulation model of filling and solidification was built by combining a three-dimensional thermo-pressure coupled field with data on the evolution of molten metal filling and solidification.

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