Papers by Keyword: Foundry

Abstract: The current market change of aluminium HPDC castings started with the “Dieselgate”. First, there was a shift from diesel to petrol engines. In the second step, hybrid and battery-powered cars gained significant market shares in sales statistics. Therefore, lucrative powertrain components are falling away. As powertrain foundries still want to utilize their machines to capacity, they are pushing into the structural castings market. As a result, there is an oversupply of casting machines here, which massively depresses prices and, thus, margins for tenders. With rising energy costs, these declining margins were eaten up, bringing foundries into crisis. Implementing Rheocasting at the existing die-casting cells is the solution to move into new market shares that are now not accessible in conventional HPDC.One of the new applications is electronic housings, high wall thickness parts, and fatigue bearing parts. These parts are commonly manufactured in sand or gravity castings because of their high wall thickness and low tolerance of porosity. Rheocasting is the perfect process for high-wall thickness components. Because of the semisolid melt preparation and the lamellar filling behavior, these components can be manufactured from the same alloy without pores or voids.This flow behavior of the semisolid slurry also results in a longer flow length. Slower casting speeds and lower pressure settings result in lower clamping forces. This gives an advantage in production costs and targets battery constructions made of castings and sheet metal. Structural battery housings must be leak-tight, even in a crash event. Having it in one casting instead of an assembly reduces the leakage area and improves crash performance.Another industry that relies on Rheocasting is the telecommunications industry. The power electronics in these 5G modules are significantly larger and generate much more waste heat. Until now, many antennas have been actively cooled or milled from a block of aluminum. The milled housings are significantly too expensive to enable series production. Therefore, the goal is to reproduce the passively cooled modules in die casting. Due to the process, the thermal conductivity in conventional HPDC is around 120 to 130 W/m*K. Similarly, no slim cooling fins can be formed. Only the Rheocasting process makes it possible to cast other alloys with low proportions of alloying elements, such as AlSi2Mn. This allows fins with a wall thickness of down to 0.4 mm and thermal conductivity of up to 190 W/m*K.Rheocasting enables access to market segments out of reach. These bring an unbeatable cost advantage against the current suppliers: gravity and sand casters. The low cycle time in Rheocasting brings back the high margins needed to sustain the business. Also, these products can be delivered with even better properties on smaller casting machines.

Abstract: Modern metal melting includes of cast iron production in different types furnaces with specific characteristics. Furnaces usually adopted are cupola and induction furnaces. Casting cast iron is a manufacturing process characterized by its energy-intensive nature (ie, the use of large amounts of energy per unit of product for main activities) and a long tradition. An example of the energy balance in a foundry is the design of procedures to reduce energy consumption. The most important is the consumption of energy in the production of hot metals (52%), therefore reducing the cost of preparing hot metal is especially important by reducing the energy consumption of metal melting. The most important energy cost practices are the consumption of hot metal to produce 1mt of high quality castings (often 1700 kg) and reduce the energy consumption of hot metal production that varies over a wide range (from 500 to 1300 kWh/mt). Although scientific and technological aspects are now well established, new studies seem to be needed to describe "foundry of the future", where energy and material efficiency is of great importance to ensure competitiveness alongside environmental protection. The paper presents specific procedures for reducing both economically important indicators in cupola and electric induction furnaces.

Abstract: Modernization of physical and mechanical properties of casting alloys, through the introduction of new processes, which can be used to obtain a precise casting with a smooth surface, which does not require machining, with a constant increase in the productivity of the implemented processes, is changing the technological and economic profile of modern foundry. The most advanced equipment is the induction crucible, melting furnace, which belongs to the main production assets and has a direct impact on productivity and, consequently, on profitability. For this reason, it is the main factor determining the content of the development strategies of the enterprise as a whole. Since 2000, iron scrap has been gone, due to the active sale of it abroad, the cost of pig iron and foundry has increased dramatically, in addition, the cost of their delivery increased. This led to higher prices in the production of castings made of synthetic iron, due to the increase in the cost of batch materials. In addition, there were problems with the use of acidic lining, as the cheapest and having a high resistance, as a part of the metal began to use an increased amount of scrap steel and, for this reason, to raise the melting temperature above 1450 Celsius. For this reason, the efficiency of production must be paid great attention.

Abstract: This paperwork presents the results of a series of experiments on the use of homogenizing annealing, aimed at the possibility to control the structure and properties of steel samples obtained by aluminothermy. This method of processing, in some cases, allows to eliminate the need to use subsequent heat treatment operations due to the achievement of the required properties by the cast blank material. Refractory materials and thermite mixtures used, conditions for the production of castings and their total chemical composition are given. The tensile diagram analysis of the samples before and after heat treatment is presented; the structures and diffraction patterns of the samples’ destruction spots are considered. The material obtained by aluminothermy corresponds in its chemical composition to A1, A2, A3, A4 grade of steels for the rail transport according to GOST 31334-2007 which are used in the manufacture of locomotive axes and other rolling stock.

Abstract: Features of the process of injection molding of non-ferrous metals and zinc alloys, in particular, consisting in the rate of crystallization of the process of melting, as well as cyclically repetitive temperature and shock loads of the forming surfaces of the mold, cause most defects, in which the form can be considered unfit for further use.

Abstract: This paper presents the development of 1700V-rated 4H-SiC JBS diodes in the state-of-the-art 6-inch SiC-dedicated foundry, NY-PEMC (New York- Power Electronics Manufacturing Consortium). The critical considerations in developing the SiC JBS diode including the cell optimization, edge termination design, process flow, and unit process developments are discussed in this paper. Static device performances such as forward conduction and reverse blocking behaviors of fabricated 1700V, 20A-rated JBS diode are presented.

Abstract: In the present condition, customer demand has increased gradually due to technological development and globalisation in this world. So this made the industrialist to deliver the products at right quantity at right place at right time with shorter lead time. But due to high rejection rate the industries fails to meet the customer demand which in turn reduces the customer satisfaction. Hence, this research an attempt was made to reduce the defects of casting components in an original equipment manufacturer. The study was carried out in a foundry of brake drum manufacturing industry. The problem was inside that the industry could not meet the customer demand due to high rejection rate and the major contributor for high rejection is found to be sand drop. Hence, proposed solutions have been implemented to achieve the objectives. After implementation of proper lean tools it was observed from the results that, the rejection rate was reduced by about 4% and the quality level was increased by about 4.4%.

Abstract: The effect of melt superheat and oxide inclusions on the fluidity of a commercial A356 alloy has been investigated. Fluidity measurements have been performed by means of Archimedean spiral in sand moulds. The specific testing method and the experimental apparatus show a good reproducibility. Metallographic and image analysis techniques have been used to quantitatively examine the microstructural changes and the amount of defects occurring at the tip of the spirals. The results reveal that oxide films increase the variability in the fluidity results obtained at the same apparent experimental conditions. A long permanence in the holding furnace and the introduction of some turbulence during sampling increase the oxide formation and entrapment in the molten bath, thus decreasing the repeatability of the fluidity results. The fluidity increases linearly with superheat and it extrapolates to zero at the temperature corresponding to a fraction solid of about 23%. The initial Ti content in the alloy produces an independent crystallization during freezing of the fluidity spirals.

Abstract: The metallurgic industry, especially foundries, is a significant source of waste. For this reason, alternatives that involve reuse and recycling are necessary to minimize waste disposal in landfills and recover matter and energy. The feasibility of elaborating ceramic matrix composites with the incorporation of foundry waste was investigated in this study. Two types of residues were used to elaborate the composites. Green sand and grit blasting powder, in formulations with concentrations that ranged from 5.0 to 10.0% (m/m). The specimens were molded by uniaxial pressing, and a thermal treatment at 1000 °C was performed. The materials were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), particle size determination, linear retraction, water absorption, mechanical strength, leaching and solubilization. The results indicate that the incorporation of waste to the ceramic mass enables the processing of specimens with properties of industrial interest, such as mechanical strength and water absorption.

Abstract: The recovery of metallic aluminum from the waste generated in the production of secondary aluminum by bioleaching process using the nutrient medium MKM was investigated. The development of this project was carried out due to the need to treat waste foundry which have a major impact on the environment, using environmentally friendly techniques, such as bioleaching. At work, bioleaching of smelting slag of aluminum generated in the laboratories of the Department of Metallurgy, Faculty of Chemistry, UNAM, was reported. Tests were conducted using thermophilic microorganisms at 70°C in an orbital incubator at natural pH, obtaining metallic clean aluminum, aluminum in solution and salts solution. The pH, bacterial growth and redox potential were monitored daily. We conclude that bioleaching of aluminum slags is feasible. The lack of information about the treatment of this type of industrial waste, makes this research is pioneer in this field.