Estimation of Position and Size of a Contaminant in Aluminum Casting Using a Thin-Film Magnetic Sensor

Advanced manufacturing processes require an in-line full inspection system. A nondestructive inspection system able to detect a contaminant such as tool chipping was utilized for the purpose of detecting a defective product as well as damaged machine tools used to fabricate the product. In a previous study, a system able to detect magnetic tool steel chipping in conductive material such as aluminum was developed and tested. In this study, a method of position and size estimation for magnetic chipping was investigated and is described. An experimental confirmation of the proposed method was also carried out using an actual prototype system.

Effect of temperature, time, and shear force on the morphology and size of dendrites in A356-Al2O3 composites

Dendrite arm spacing (DAS) plays a vital role in determining mechanical properties of aluminum casting composites. In this study, the effects of three different methods of gravity sand casting, squeeze casting, and semi-solid compo-casting with different electromagnetic stirring currents and times on the microstructural morphology of A356-Al2O3 composites were investigated. In order to investigate effects of shear forces on the formation of the globular-like structure, samples with different stirring electric current and times were produced by compo-casting in semi-solid state and analyzed. Optical emission microscopy was used to study the microstructure and DAS of nanocomposites. Quantitative analysis of microstructure was performed by utilizing an image analysis system. In this study, the optimum temperature for composite fabrication for this type of composite was calculated to obtain the most appropriate morphology and size of the microstructure. Also, the appropriate time to keep this composite at this temperature was obtained, and finally the relevant microstructures were fully discussed.

Study of Heat Transfer Rate in Electric Evaporators of Liquefied Petroleum Gas Using Electrothermal Modeling

In modern domestic and foreign experience of gas power supply to houses and industrial facilities located remotely from the main power station, decentralized gas power supply systems fed with propane-butane mixtures of liquefied petroleum gases from tanks are increasingly used. When using liquefied petroleum gases as the main energy carrier in gas tank systems, they are evaporated artificially in evaporators with an intermediate solid-state or liquid heat transfer agent, under conditions of its natural convection. The main operational characteristic of industrial tube evaporators of propane-butane mixtures of liquefied petroleum gases used for gas power supply from tank installations of housing and communal, industrial and industrial facilities that are remote from the main power supply stations is evaporation capacity. The evaporation capacity of industrial tube evaporators of propane-butane mixtures with a solid-state intermediate heat transfer medium is determined by the heat input from the tubular electric heaters through the aluminum casting layer. Therefore, the study of heat transfer in the solid–state intermediate heat transfer medium-evaporation coil system is the most important prerequisite for the effective operation of industrial tube evaporators of propane-butane mixtures and requires detailed research. To solve the problem of determining the heat transfer resistance between the layers of aluminum casting in contact with the surface of the tubular electric heaters group and the outer evaporation coil surface studies were performed on an electrical model. The average value of the total error of the results of experimental studies on electrothermal modeling is 3.7 %, with a confidence probability of 95 %. Recommendations are given for reducing the thickness of the layers in clear from the lower coil of the evaporative tube coil to the lower generatrix of the solid-state aluminum mass and the upper coil of the evaporative tube coil to the upper generatrix of the solid-state aluminum mass.

High-Shear De-Gassing and De-Ironing of an Aluminum Casting Alloy Made Directly from Aluminum End-of-Life Vehicle Scrap

High-shear melt conditioning (HSMC) technology was used for degassing and de-ironing of an aluminum alloy recovered from the Zorba cast fraction of the non-ferrous scrap from shredded end-of-life vehicles. The results showed that the recovery of aluminum alloys from the Zorba cast fraction was more than 80%. High-shear melt conditioning improved the degassing process during melt treatment in comparison with the adding of degassing tablets. The efficiency of the de-ironing process using HSMC increased by up to 24% after, increasing the Mn content to 0.8% in the melt. Adding Mn to Zorba melt enhanced the de-ironing process and eliminated the formation of β-AlFeSi intermetallic particles, which have a detrimental effect on both the mechanical and corrosion properties of the alloy.

Casting of complex structures in aluminum using gypsum molds produced via binder jetting

Purpose The purpose of present paper is to enlarge the knowledge about the performance of gypsum powder to realize complex molds or cores for aluminum casting. Design/methodology/approach The research was divided into two activities: simple; and complex-part production capability. In the simple-part step, the performance of gypsum powder and the minimum mold thickness that would withstand the casting process. In the complex-part step, the authors first investigated the powder removability as a function of geometry complexity and then binder jetting performance was evaluated for the case of lattice-structure fabrication. Findings All the geometries tested withstand the casting process demonstrating the benefits in terms of complexity part design; however, the process suffers of all the typical defect of casting as misrun, porosity and cold shut. Originality/value The results found in this research improve the benefits related to additive manufacturing application in industrial environment and in particular to the binder jetting technology and the rapid casting approach.

Nondestructive Detection of Magnetic Contaminant in Aluminum Casting Using Thin Film Magnetic Sensor

The thin film magneto-impedance sensor is useful for detecting a magnetic material nondestructively. The sensor made by single layer uniaxial amorphous thin film has a tolerance against surface normal magnetic field because of its demagnetizing force in the thickness direction. Our previous study proposed the sensitive driving circuit using 400 MHz high frequency current running through the sensor to detect the logarithmic amplifier. We also confirmed the sensitivity of the sensor within 0.3 T static normal magnetic field, which resulted in detection of 5 × 10−8 T of 5 Hz signal. This paper proposes a nondestructive inspection system for how detecting a contaminant of small tool steel chipping in aluminum casting specimen would be carried out. Three channel array sensors installed in the 30 mT static field detecting area were fabricated and experimentally showed a detection of low remanence magnetic contaminant in a bulk aluminum casing specimen.