Simulation Of Casting Process Research Articles

An overview of the effect of stirrer design on the mechanical properties of Aluminium Alloy Matrix Composites fabricated by stir casting

An overview of the effect of stirrer design on the mechanical properties of Aluminium Alloy Matrix Composites fabricated by stir casting

Failure analysis of a clutch wheel for wind turbines with the use of casting process simulation

Production of high-quality and high-grade casts at the lowest possible cost is a priority of every foundry. Innovation and optimization of the currently applied production processes is a necessary step to achieving such a goal. Costly and long experiments performed in real foundries may be replaced with numerical simulations, as they provide reliable representation of the casting process using the computer technology. A detailed analysis of simulation results facilitates forecasting various risks that might negatively affect the quality of produced casts, and hence the quality of the entire production process. The present article discusses the effects of adjustments to the design of a gating system on the quality of a cast made of EN-GJS-500-7 ductile cast iron, which is used as a clutch wheel in turbines in wind power plants. During the production of the cast, two models of the gating system were created in Solid Works CAD software. The gating systems were validated using NovaFlow&Solid casting simulation software. The modification of the gating system design resulted in a reduced amount of liquid metal used for casting, which has significant economic effects in the mass production. Eight simulations of the designed gating systems were carried out. The main purpose of the simulations was to determine the mesh density as well as the casting and solidification conditions so that they are as close as possible to the real conditions in a foundry. Subsequently, the gating system was modified with the result of eliminating defects in the cast that occur during the solidification process as well as increasing the utilization of liquid metal.

Structure Optimization of Semi-Solid Die Cast Steering Knuckle and its Experiment Verification

Steering knuckles are vital functional and structural components in automotive suspension systems, requiring high strength, high ductility, and complex shapes. In this study, an aluminum alloy knuckle with the semi-solid die casting process was developed to replace the conventional steel components. This research aims to optimize product design based on both structural simulation and casting process simulation to avoid defects and to meet mechanical requirements. Furthermore, the optimal design solutions need to be verified through the filling experiments and defect analysis. The results show that the removal of support rib located in the thick area of the shock absorber mounting arm is helpful to avoid the rewelding defects in the filling frontier of the SSM melt. Besides, the position of the steering rod is of medium thickness, and two ribs from different directions come together to support that area. Rewelding defects were detected when two ribs come together. To avoid rewelding defects in local areas of steering rod position, the ribs were reduced to uniform wall thickness. Thus, the local flow state was modified and the SSM melt was reinforced shear action. Ultimately, by controlling all the processes of the SSM die casting process, the high performance of aluminum knuckle was successfully developed.

Multi-Scale Simulation of Injection Molding Process with Micro-Features Replication: Relevance of Rheological Behaviour and Crystallization.

The possibility of tailoring key surface properties through the injection molding process makes it intriguing from the perspective of sustainability enhancement. The surface properties depend on the replication accuracy of micro and nanostructures on moldings; such an accuracy is enhanced with cavity temperature. The simulation of the injection molding process is very challenging in the presence of micro and nanostructures on the cavity surface; this does not allow for the neglect of phenomena generally considered not to influence the overall process. In this paper, a multiscale approach was proposed: in the first step, the simulation of the overall process was conducted without considering the presence of the microstructure; in the second step the outputs of the first step were used as an input to simulate the replication of the microfeature. To this purpose, a lubrication approximation was adopted, and the contribution of the trapped air, which slows down the polymer advancement, was accounted for. A modification of the viscosity equation was also proposed to describe the rheological behavior of isotactic polypropylene at very low temperatures. Concerning the microcavity filling simulation, the modification of the viscosity description at low temperatures consistently describes the process, in terms of polymer solidification. Concerning the replication accuracy, it increases with the cavity surface temperature, consistently with the experimental observations.

Simulation and optimization of casting process for aluminum alloy special-shaped parts

This article is aimed at an aluminum alloy special-shaped part, which has a hollow connection inside, and there are multiple cross-sections that are constantly changing, and it is difficult to design the casting process. In response to this difficulty, combined with the existing sand casting, metal casting and investment casting production lines of the factory, the casting process plan is designed and optimized now. With the help of the numerical simulation software Anycasting, through the simulation analysis of the casting process, the problem that the castings are prone to defects in the thin wall and the bottom plate is solved. The conclusions obtained from the simulation analysis were applied to the actual production process, and qualified castings were produced.

Effect of feed sprue size on porosity defects in Platinum 950 centrifugal investment casting via numerical modelling

The centrifugal investment casting process is typically used in the jewelry manufacturing industry. However, porosity defects are often found in jewelry castings made by this process. Porosity on the casting surface is a major concern for jewelry manufacturers as the defect leads to significant yield losses during the repair work. Improper feed sprue design is one of the major causes of porosity defects. The purpose of this work is to study the effect of feed sprue size on porosity defects in Platinum 950 jewelry made by the centrifugal investment casting process. Two feed sprue sizes were experimented in this study. FLOW-3D CAST software was employed for the casting process simulation. Simulation results were analysed together with experimental results quantified by an image analysis technique. The results show that the larger feed sprue provides castings with less porosity compared to the smaller feed sprue.

A Comprehensive Assessment of Commercial Process Simulation Software for Compression Moulding of Sheet Moulding Compound

With a growing interest in the application of carbon fibre Sheet Moulding Compound (SMC), a number of commercial software packages have been developed for the simulation of compression moulding of SMC. While these packages adopt different algorithms and meshing strategies, the constitutive material model and processing control are usually adapted from injection moulding process simulation. Little has been done in the literature for assessing the capabilities of these software as design tools, and more importantly, validating the process simulation results using experimental data. This paper aims to provide an independent and comprehensive assessment of existing well-known process simulation software for SMC compression moulding. The selected software will be compared in terms of material models, and available processing settings in order to determine their robustness as a compression moulding design tool. The predictive accuracy of the software will also be assessed by comparing the compression force and filling patterns against the experimental data.

Modelling and simulation of the freeze casting process with the phase-field method

The freeze casting process is a novel manufacturing method for both near net-shape parts as well as directed porous structures as employed by filters and implants. Depending on the choice of liquid and processing conditions a very wide range of pore shapes and sizes can be achieved. In order to predict the resulting microstructure, a phase-field model is developed on the basis of the grand potential formalism. The model and its parametrization approximate the freeze-casting process of water by linking its thermodynamics with established theory. Directional solidification simulations with varying suspension concentrations, velocities and temperature gradients are carried out. From these, microstructural lengths are determined and linked with the processing parameters, so as to derive linkages between the microstructure and the processing conditions.

A Study on Hot Tearing in Direct Chill Casting of Al-Mn-Mg Alloys Using a Multi-scale Approach

A multi-scale approach for simulating hot tearing during the DC casting of aluminum alloys is presented. The novelty of this approach lies in the combination of a macro-scale finite element simulation of the DC casting process with direct prediction of hot tears via a meso-scale multi-physics granular model. This approach is capable of simulating hot tearing initiation, growth, and propagation within a representative volume element of the mushy zone. The change of cooling conditions experienced by the DC cast billet as a result of variations in casting speed as well as non-uniformity of heat extraction from different locations of the billet affect the deformation state, cooling rate, and thermal gradient, which further influence the strain rate, grain size, permeability, and feeding coefficient. Considering all the mentioned parameters, the multi-scale approach emphasizes the fact that hot tearing is a phenomenon resulting from the combination of the tensile deformation and restricted feeding of the mushy zone. The developed hot tearing formation maps identify the locations where hot tearing will occur as predicted by the multi-scale approach for two alloys—AA5182 and AA3104—thus demonstrating the approach’s sensitivity to both processing parameters and alloy composition.

Research on Compression Molding Process of Carbon Fiber Reinforced Polymer

The compression molding process of CFRP(Carbon Fiber Reinforced Polymer) is a multi-parameter coupled system, and its molding mechanism is very complex. Based on the Gel point and the glass transition temperature of the matrix material, the compression molding process of CFRP is divided into three sub-processes: thermal-chemical process, flow-compaction process and residual stress-deformation process, and the mathematical constitutive model of each sub-process is established. On the basis, the interaction and calling relationship of each sub-process are determined, which lays a foundation for the molding process simulation of CFRP and further analysis of its multi-parameter coupling effect mechanism.

Research progress on selective laser melting of hard composite materials

Composite materials are made of multiphase materials composed of two or more materials with different properties. Hard composite materials are often used as alloy materials for tool production due to their high hardness, high strength and good wear resistance. This paper briefly introduces the domestic and foreign research progress and technical status of hard composite materials by laser area melting, summarizes the influence of forming powder and process parameters on the forming performance characteristics of hard composite materials, as well as selective laser melting area of hard composite materials. The quality inspection and molding process simulation of the company, and prospects for the future development, provide a reference for the laser melting “3D printing” of hard composite materials.

Metal casting modeling software for small scale enterprises to improve efficacy and accuracy

In the modern casting and metal casting industries, casting modelling software is rapidly being used. The casting process is simulated by software in a virtual field and provides insight into mould filling, solidification and cooling, and defects in casting. The designer will model, check and confirm the procedure, managed with design optimisation through simulation casting. This essay seeks to discuss the techniques of modelling and simulation of metal casting processes with regard to several relevant case studies. The most popular cast simulation programme available and the mathematical models used are briefly presented. The simulation of the method of casting along with the findings obtained is well described. Literature case studies showed that by providing a detailed knowledge of mould filling and solidification, gating, runner and feeding system setup, and other process parameters, simulation instruments play a crucial role in manufacturing high quality defect free cast products. Recent attempts are being explored to incorporate casting simulations into mechanical simulations of results, which is very exciting in predicting service life for cast goods. The result is that simulations in the casting processes have been well developed and more developments in simulation techniques are required to estimate durability of castings.

Effects of stir casting process parameters on dispersion of reinforcement particles during preparation of metal composites

Abstract The flow behavior of the liquid metal during the stir casting process significantly affects dispersion of reinforcement particles in Metal Matrix Composites (MMCs). Liquid metal processing is carried out in an opaque crucible, in which the flow patterns are invisible. Hence, numerical simulation is an apt tool to understand flow behavior and particle dispersion. Blade angle and stirring speed are two important factors ultimately resulting in the final quality of the composites. Thus, in the present investigation, simulation of stir casting process has been performed to optimize blade angle and stirring speed. In order to compare the results of simulation, MMCs were developed using a conventional stir casting technique. Microscopic investigation and porosity analysis has been incorporated to study dispersion of reinforcement inside molten matrix. Microstructural investigation unveiled the homogeneous distribution of SiC particles in the molten matrix and grain size of composite material is reduced by 10.5% as compared to matrix material.

Study on Injection Molding Process Simulation and Process Parameter Optimization of Automobile Instrument Light Guiding Support

In the present study, Moldflow® software is applied to simulate the injection molding of automobile instrument light guide bracket and optimize the injection gate position. In this regard, Taguchi orthogonal experimental design is adopted, and five processing parameters, the mold temperature, melt temperature, cooling time, packing pressure, and packing time, are considered as the test factors. Moreover, volume shrinkage and warping amount are considered as quality evaluation indices. Then range analysis and variance analysis are carried out to obtain the optimal combination of molding parameters with the volume shrinkage rate and the warpage amount. The grey correlation analysis was used to analyze the test results and obtain the optimal combination of volume shrinkage rate and amount of warping. Based on the performed simulations, it is found that the maximum volume shrinkage rate and the maximum amount of warping in the optimal design are 6.753% and 1.999 mm, respectively. According to the optimal process parameters, the injection molding of the automobile instrument light guide bracket meets the quality requirements.

A Numerical Model for Steel Continuous Casting Problem in a Time-variable Domain

A mathematical model and numerical method for simulation of the continuous casting process in a variable in time domain are presented. The variable geometry of the slab is caused by the change in time of the width of the mould. The mathematical model of the process is a Stefan problem with prescribed convection and non-linear Robin boundary condition. Considered differential equation is approximated by a finite difference scheme, which is constructed in several steps. First, a semi-discrete problem is constructed using the method of characteristics with respect to the time variable. Then, at each time level, the current elliptic problem in a curvilinear domain is replaced by a problem in the parallelepiped domain using the fictitious domain method. Finally, the boundary-value problem in the parallelepiped domain is approximated by a finite-difference scheme. The constructed fully discrete problem in algebraic form is a system of nonlinear equations containing a diagonal monotone operator and a linear part with a symmetric and positive definite $$M$$ -matrix. To solve the resulting system of nonlinear algebraic equations, well-known iterative solution methods can be applied.

Mechanism of δ → δ + γ phase transformation and hardening behavior of duplex stainless steel via sub-rapid solidification process

In this contribution, a duplex stainless steel (DSS) strip is obtained under the sub-rapid solidification condition by a recently developed fast dip tester, which is designed for simulation of the strip casting process. The mechanism of δ → δ + γ phase transformation and hardening behavior of DSS via the sub-rapid solidification process are investigated. The results suggest that the DSS under a rapid cooling rate would go through a shear/semi-shear phase transformation, which is different from the traditional diffusional transformation. There is no noticeable element precipitation content difference between the ferrite and austenite phases, and more dislocations are formed inside the austenite grains in the sub-rapid solidified sample. Furthermore, the austenite fraction of the sub-rapid solidified sample (4.08–4.32%) is substantially decreased compared with the slow solidified sample (36.12–39.37%). The length of grain/phase boundary, especially the dispersed small austenite particles is increased significantly. Besides, the hardness is increased to 311 HV and the wear-resisting property is enhanced with the wear consumption decreasing from 0.0291 to 0.0122 g, due to the multiple hardening effects under sub-rapid solidification process, including higher ferritic friction, grain refinement hardening, and dislocation hardening.

On Numerical Simulation of Casting in New Foundries: Dynamic Process Simulations

New and more complex casting technologies are growing, and foundries are using innovative methods to reduce cost and energy consumption and improve their product qualities. Numerical techniques, as tools to design and examine the process improvements, are also evolving continuously to embrace modelling of more dynamic systems for industrial applications. This paper will present a fresh approach towards the numerical simulation of dynamic processes using an evolving and dynamic mesh technique. While the conventional numerical techniques have been employed for these dynamic processes using a fixed domain approach, the more realistic evolving approach is used herein to match the complex material processes in new foundries. The underpinning of this new dynamic approach is highlighted by an evolving simulation environment where multiple mesh entities are appended to the existing numerical domain at timesteps. Furthermore, the change of the boundary and energy sources within casting process simulations have rationally been presented and its profound effects on the computational time and resources have been examined. The discretization and solver computational features of the technique are presented and the evolution of the casting domain (including its material and energy contents) during the process is described for semi-continuous casting process applications.

Experimental Validation of Injection Molding Simulations of 3D Microparts and Microstructured Components Using Virtual Design of Experiments and Multi-Scale Modeling.

The increasing demand for micro-injection molding process technology and the corresponding micro-molded products have materialized in the need for models and simulation capabilities for the establishment of a digital twin of the manufacturing process. The opportunities enabled by the correct process simulation include the possibility of forecasting the part quality and finding optimal process conditions for a given product. The present work displays further use of micro-injection molding process simulation for the prediction of feature dimensions and its optimization and microfeature replication behavior due to geometrical boundary effects. The current work focused on the micro-injection molding of three-dimensional microparts and of single components featuring microstructures. First, two virtual a studies were performed to predict the outer diameter of a micro-ring within an accuracy of 10 µm and the flash formation on a micro-component with mass a 0.1 mg. In the second part of the study, the influence of microstructure orientation on the filling time of a microcavity design section was investigated for a component featuring micro grooves with a 15 µm nominal height. Multiscale meshing was employed to model the replication of microfeatures in a range of 17–346 µm in a Fresnel lens product, allowing the prediction of the replication behavior of a microfeature at 91% accuracy. The simulations were performed using 3D modeling and generalized Navier–Stokes equations using a single multi-scale simulation approach. The current work shows the current potential and limitations in the use of micro-injection molding process simulations for the optimization of micro 3D-part and microstructured components.

Control of as-cast microstructure morphology of high silicon electrical steels produced through a horizontal belt casting process simulator

ABSTRACT Increase in global electrification is driving the development of new electrical steels with improved performance, such as Fe–6Si suitable for high-frequency e-machines. Fe–6Si steel is difficult to cast and roll such that currently, the only commercial production is via downstream siliconisation to increase Si content. This paper explores the feasibility of casting ultra-high silicon electrical steels through a belt cast simulator and how the microstructure depends on casting parameters. Changes in the superheat, belt profile, belt coating and cast thickness have been considered and shows that microstructures from large columnar grains with a highly favourable {100} texture, to fine equiaxed random texture grains can be produced. It is also shown that casting to thicknesses of around 3.5 mm can be achieved such that a minimal amount of deformation is needed to produce the final product (around 0.1 mm thick), which will reduce the likelihood of cracking during rolling.

Advanced modeling of shrinkage porosity in castings

Porosity due to solidification shrinkage is a troublesome defect in all types of metal castings. It limits the performance of cast components by adversely affecting the material’s strength, fatigue and creep properties. By reliably predicting porosity in casting process simulation, it can be minimized or eliminated. Here, a newly developed model for predicting porosity is presented. The model is based on the recent discovery that all shrinkage porosity nucleates and grows in regions of a casting where the solid fraction is the lowest. It calculates the feeding flows and pressure distribution in the liquid while accounting for the liquid density variation during cooling and solidification. It predicts the location, extent and amount of all types of shrinkage porosity in a casting, including riser pipes and large internal holes, surface sinks, and distributed micro-shrinkage. The model is numerically implemented in a standard casting simulation code. Comparisons to measurements in specially made steel castings demonstrate the capability of the model to accurately predict various types of shrinkage porosity.