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Microwave Processing of Materials
Published in Amit Bansal, Hitesh Vasudev, Advances in Microwave Processing for Engineering Materials, 2023
T. Lachana Dora, Radha Raman Mishra
Microwave casting is a recently explored area of microwave applications. Microwave casting can be classified into two types: in situ (charge melting and casting are accomplished inside the microwave applicator cavity) and ex situ (only charge melting is carried inside the microwave applicator cavity) microwave casting. The schematic of the in situ microwave casting is shown in Figure 1.7. A pouring basin is used to melt the charge, and the melt passes through a sprue. The sprue guides the molten metal to fill inside the mold cavity and subsequent solidification. In contrast, in the ex situ microwave casting method, the charge is melted using microwave irradiations and solidification of the melt is done outside the cavity. The ex situ microwave casting resembles the conventional casting process and lacks benefits like control over the mold preheating temperature, molten metal flow, and grain growth as achieved in the in situ microwave casting [21]. The process was used for casting of Al alloy [22–25] and Ni-based metal matrix composite [26–27].
Metals I: Metals Preparation and Manufacturing
Published in Ronald Scott, of Industrial Hygiene, 2018
Shaping a metal object into a finished product often requires removal of metal. As an example, consider castings. The sprue or risers must be cut off a new casting using a cutting wheel (a spinning, abrasives-coated wheel) or a saw. A flat surface may be ground onto a casting using abrasives so that two structures can be joined tightly. For example, surfaces may be ground flat to connect an internal combustion engine to some sort of transmission. These two objects may be assembled by bolting them together. To accomplish this holes are drilled through one object and into the other. A hole may later be tapped, that is, threads that will anchor the bolt may be cut into the walls of the hole with a thread-cutting device.
Motor Frame Design
Published in Wei Tong, Mechanical Design and Manufacturing of Electric Motors, 2022
Full-mold casting combines sand casting and lost-foam casting. It employs an expandable polystyrene (or foamed polystyrene) pattern, which is supported by sand in a single-piece sand mold. The molten metal is then poured through the sprue into the mold. With the progressive evaporation of the pattern material, the molten metal fills the available space. This casting process can make complex-shaped parts (e.g., automobile engines) without using cores and drafts.
Effect of input microwave power and insulation on microstructure and tensile properties of cast Al 7039 alloy produced at 2.45 GHz
Published in Journal of Microwave Power and Electromagnetic Energy, 2020
Radha Raman Mishra, Apurbba Kumar Sharma
A multi-mode microwave applicator (Model: MH-1514-101-V6, Make: Enerzi Microwave Systems Pvt. Ltd., India) was used to irradiate the charge. A schematic diagram of in situ microwave casting set-up is shown in Figure 2. The casting set-up consists of a base, split mould, pouring basin, susceptor and sprue. The charge was placed inside a ceramic crucible which acts as a pouring basin and absorbs microwave energy. Graphite was used as mould material, and solidification of the melt was allowed inside the split mould (cope and drag). The sprue material was alumina, which facilitates self-pouring of the melt into the mould cavity. A low dielectric loss ceramic plate was used as the base, which avoids the possibility of thermal damage in the cavity floor. An additional SiC susceptor was used to accelerate the microwave heating process. An optional thermal insulation material, which acts as a microwave transparent material, was used to reduce heat losses from the mould assembly. The mould assembly was placed inside the cavity as shown in Figure 2. Positions of the charge and mould assembly were fixed using a laser control (Figure 2). The temperature at the top surface of the charge was monitored using a built-in infrared (IR) pyrometer (range: 350 °C − 1800 °C, least count: 1 °C).
Casting of adjuster bracket—process optimization and validation
Published in Materials and Manufacturing Processes, 2018
Anwar K. Sheikh, Muhammad A. A. Khan, Hassan Iqbal, Bilal S. Al-Shaer
The progress of cooling from casting surface to interior is monitored by solidification simulation. The solidification sequence in terms of percentage of fraction solid at 50% solidification is presented in Fig. 4(b). A detailed presentation of solidification sequence within the mold at different time intervals is provided in Ref. [23]. Simulation confirmed that the last region to solidify will be sprue in the gating system. The whole casting system including the adjuster bracket, gates, runner, and sprue took approximately 190 s for complete solidification.
Physical chemistry and technology of mullite-corundum refractories for casting special steels
Published in Canadian Metallurgical Quarterly, 2022
Dmitry Pruttskov, Vladimir Sokol’skii, Aleksey Kirichenko, Illia Prokhorenko, Georgiy Sokolsky, Oleksandr Roik
A set of siphon products has been made consisting of a central tube (inner diameter 100 mm), a four-channel star, through and end siphons, and a cup for the mould (all of them have a channel diameter of 50 mm). The standard receiving funnel has been used (>32 mass % Al2O3, GOST (National Standard) 1956:2006). Refractories were tested at OJSC Dneprospetsstal (Zaporozhye, Ukraine). Cast steel bushes were constructed on railway platforms. Steel was smelted in an arc furnace with a capacity of ∼60 tons and poured into ingots weighing ∼3.8 tons, after refining in a ladle furnace and a degasser. The resulting ingots were rolled in turn into blanks of square (edge 108 mm) and then round (diameter 27–45 mm). At the testing stage, 22 melts of ball-bearing and 7 melts of tool steels were poured using these refractories. The siphon set was manually disassembled and visually inspected after cooling. The wear of refractories was determined by measuring the diameter of the metal solidified inside the channel (so-called ‘sprue’). As it turned out, the channel of the through siphon is most susceptible to blurring by a jet of moving metal. For example, when casting ball-bearing steels through standard siphon products (>32 mass % Al2O3, GOST 11956:2006), the sprue diameter reached 62–64 mm (i.e. wear 6–7 mm), and its surface was covered with strongly bonded refractory fragments. At the same time, in the case of using mullite-corundum products, both experimental and ‘LWB-Refractories’, the sprue diameter was only 52–53 mm (that is, wear 1.0–1.5 mm), and its surface was clean. The content of non-metallic inclusions in steel, determined according to ASTM E-45, was the same in both cases. The number of rejects decreased by ∼1.5 times [1,2] in comparison with standard siphon products in the case of using mullite-corundum products. However, the use of such a multicomponent charge causes organisational and technical difficulties, and the use of an expensive rutile concentrate increases production costs.