Solidification and Microstructure Simulation of A356 Aluminum Alloy Casting

To obtain an A356 aluminum alloy casting with a uniform structure and no internal shrinkage defects, ProCAST software is used to set different filling and solidification process parameters for an A356 aluminum alloy casting with large wall thickness differences, And multiple simulations are conducted to obtain optimized casting process; then, based on the process, the microstructure of the thickest and thinnest part of the casting are simulated. The size, morphology, and distribution of the simulated microstructure of the thinnest part and the thickest part of the casting are very similar. The simulated microstructure is similar to that of the actual casting. This shows that castings with uniform structure and no internal shrinkage defects can be obtained through the optimized casting process .

Influence of constructive and geometric parameters of the end cutters on the microprofile characteristics of casting surfaces

The object of research is the technological route of machining of an aluminum alloy casting. The research carried out is based on the basic principles of functionally oriented design of technological processes in the manufacture of products. The main hypothesis of the study is the need for a systematic approach to study the effect of cutting modes of a certain method of machining on the provision of quality parameters in the technological system (machine – device – tool – workpiece). In traditional automated systems for technological preparation of production, an object-oriented principle of designing technological processes is implemented, which provides for the step-by-step implementation of interrelated stages based on a prototyping algorithm without a functional analysis of the operational characteristics of the product. The processing of functional, mating surfaces, ensuring that the product performs its service purpose, must be implemented according to the principle of function-oriented design (FODT). A characteristic feature of FOT is the technological provision of effective operational characteristics of the product in compliance with the parameters of accuracy and quality of the surface layer of the product intended by the designer. The paper deals with the influence of the structural and geometric parameters of end mills manufactured by Sandvick (Sandviken, Sweden) on the formation of microrelief parameters of an aluminum alloy casting profile during machining on a numerically controlled vertical milling center (CNC) HAAS MINIMILL (USA). An atypical option for the FOT principle of the technological route of machining the surfaces of workpieces of machine-building products has been applied. Its feature is ignoring the requirements of the manufacturer of metal-cutting tools, which is an important element of the technological system (machine – tool – device – workpiece), regarding its use for a particular machine tool at a certain technological transition of machining. The performance criteria were the height and step characteristics of the microrelief of the profile of the surface layer of the workpiece being processed. The operating conditions of machine-building products have been determined, which make it possible to establish, in case of deviation from the manufacturer's recommendations at the stage of technological preparation of production, the rational elements of a certain technological system: a metal-cutting machine – a device – a metal-cutting tool – a workpiece and processing modes to ensure the necessary operational characteristics.

The Effect of Fe Addition on Microstructure, Mechanical Properties and Electric Conductivity of the As-Cast Al–Mg–Si Alloys

Fe is considered as one of the most harmful trace elements among impurities in aluminum and its alloys due to its influence of the mechanical properties especially in elongation. It is therefore essential that the Fe content is controlled to improve quality and the toughness of aluminum alloy castings. Since demand for high strength aluminum alloy casting was significantly increased in electro materials and devices, automotive and airplane industries, it is necessary to characterize the effect of Fe and set the tolerable amount of Fe content in aluminum alloys. Al6061 alloys were prepared with compositions of 0.36, 0.45, 0.58, 0.65, 0.75, 0.81 and 0.91 wt.% Fe. Solidification characteristics were analyzed by CALPHAD (Pandat software) method. Mechanical properties such as hardness, tensile strength, elongation and fatigue strength were evaluated and compared with different Fe contents. Al13Fe4 phase increased with increasing as Fe content, however, other phases, α-AlFeSi and Mg2Si, showder a slight decrease. The higher the Fe content, the lower the electrical conductivity of the alloy due to the severe distortion of the Al matrix. As Fe content was more than specification of Al6061 alloy, 0.7 wt.%, the mechanical properties, especially, hardness and elongation were greatly influenced. The hardness is attributed to the poor densification and angular-shaped Al13Fe4 phases unevenly distributed in the α-Al matrix.

Simulation and Experiment of New Ultrasonic Vibration Network

A reasonable ultrasonic vibration network can improve the casting quality of aluminum alloy. Ultrasonic vibration network based on a honeycomb structure has been designed, referred to as a new vibration network. The new vibration network can solve the problems of nonuniform distribution of power ultrasonic wave, small working area and low volume of ultrasonic vibration network, low efficiency of the frequency spectrum and power spectrum, and poor quality of aluminum alloy casting. The number of vibration nodes can be determined based on the number of layers of the vibration source nodes. The edge length of regular hexagonal honeycomb cells can be determined based on the size of the casting ingot. The output power and resonant frequency of the ultrasonic vibration network can be adjusted in real time according to the status of aluminum alloy melt. A seven-node new ultrasonic network and a four-node ultrasonic network with a traditional structure were selected and used in the experiment and simulation of a 500 mm diameter 2219 aluminum alloy ingot. In comparison with the traditional four-node ultrasonic network, the effective volume and area, frequency spectrum efficiency, and comprehensive coverage probability of the seven-node new ultrasonic vibration network increased by 34.06%, 23.12%, 17.25%, and 0.308, respectively. The difference between the desired value and average efficiency of the power spectrum was 0.292 W/cm2, and the average grain size of aluminum alloy decreased by 34.98 microns. These results indicate that the efficiency of ultrasonic-vibration-assisted casting system and the quality of aluminum alloy casting can be improved using the new ultrasonic vibration network.

Casting and Forming of Advanced Aluminum Alloys

The automotive and aeronautical industry´s response to the environmental impact provoked by gas emissions and consumer expectations has driven aluminum alloy casting changes in recent years [...]

Metal Casting Research: Application to Aluminum Alloy Casting

Guidelines for designing research on cast aluminium alloys have been developed to increase the reproducibility of results and make their interpretation more objective. These guidelines, based on the scientific method and recent research findings, are proposed for research on aluminium castings, but they can be easily adapted for other casting alloys.