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Motor Frame Design
Published in Wei Tong, Mechanical Design and Manufacturing of Electric Motors, 2022
As a member of the cast iron family, ductile iron contains 3%–4% carbon and 1.8%–2.8% silicon. This type of cast iron has high strength. Unlike gray cast iron in which graphite is presented as flakes, ductile iron contains tiny graphite nodules, which make cracking more difficult. Therefore, ductile cast iron is much stronger and has much higher ductility than gray cast iron. In addition to high strength, the toughness and shock resistance also increase for ductile cast iron [5.5]. Furthermore, the damping capacity of ductile iron is considerably greater than most other ferrite materials (except for gray iron). These superior properties of ductile iron make it ideally suited for various industrial applications. In the motor industry, ductile iron is often used to make motor housings and endbells.
Water/Wastewater Conveyance
Published in Frank R. Spellman, Handbook of Water and Wastewater Treatment Plant Operations, 2020
Ductile-iron pipe resembles cast-iron pipe in appearance and has many of the same characteristics. It differs from cast-iron pipe in that the graphite in the metal is spheroidal or nodular form, that is, in ball-shape form rather than in flake form. Ductile-iron pipe is strong and durable; it has high flexural strength, good corrosion resistance, is lighter weight than cast iron, with greater carrying capacity for the same external diameter; and is easily tapped. However, ductile-iron pipe is subject to general corrosion if installed unprotected in a corrosive environment (Gagliardi & Liberatore, 2000).
Casting and Foundry Work
Published in Sherif D. El Wakil, Processes and Design for Manufacturing, 2019
Ductile cast iron is also called nodular cast iron and spheroidal graphite cast iron. It is obtained by adding trace amounts of magnesium to a very pure molten alloy of gray cast iron that has been subjected to desulfurization. Sometimes, a small quantity of cerium is also added to prevent the harmful effects of impurities like aluminum, titanium, and lead. The presence of magnesium and cerium causes the graphite to precipitate during solidification of the molten alloy in the form of small spheroids, rather than flakes as in the case of gray cast iron. This microstructural change results in a marked increase in ductility, strength, toughness, and stiffness of ductile iron, as compared with gray cast iron, because the stress concentration effect of a flake is far higher than that of a spheroid (remember what you learned in fracture mechanics). The disadvantages of ductile iron, as compared with gray cast iron, include lower damping capacity and thermal conductivity. Ductile iron is used for making machine parts like axles, brackets, levers, crankshafts, housings, die pads, and die shoes.
An influence of nickel with heat treatment on the microstructure and fracture toughness of austempered ductile iron
Published in Canadian Metallurgical Quarterly, 2023
Subramanya Raghavendra, J. V. Raghavendra, Manjunatha Kuntanahalli Narayanappa, Chandra Shekar Anjinappa, K. G. Srinivas, B. Manjunatha
Nodular iron, also known as ‘Ductile iron,’ is a kind of cast iron in which the graphite is arranged in the form of well-formed nodules (Spherical) rather than flakes as in typical cast iron. The proportion of carbon in nodular iron ranges from 3.2 to 3.6% [1]. Nodular iron has a wide range of uses in the automotive, industrial, agricultural, and piping industries. The typical austempering method is used to convert nodular iron to austempered structure, where austenite converts to Bainite with certain remaining Austenite. ADI finds its products beneficial in a variety of industrial sectors, including automotive, military, rail road, agricultural, earth moving, power plants, and mining. The microstructure of ADI is unusual, consisting of acicular (Bainitic) ferrite with some preserved stabilised austenite.
Cost reduction for achieving competitiveness through industrial experimentation in SG casting for Automotive application
Published in Canadian Metallurgical Quarterly, 2022
Vasu Ramanujam, K. Narashiman, Rajagopal Ananthasubramaniam
Ductile iron is defined as a high carbon-containing, iron-based alloy in which the graphite is present in compact, spherical shapes rather than in the shape of flakes, the latter being typical of grey cast iron. Higher is the carbon, more is the graphite formed, and lower are the mechanical properties. Carbon lowers the melting point of metal and thus acts as a graphatiser to favour the formation of grey cast iron. As the number of graphite increases in the melt, there is a relatively small decrease in strength, elongation, modulus of elasticity, and density. In GGG-50, ductile iron (ISO Grade) carbon requirement is 3.4%–3.6% in the final casting for sufficient graphitisation (nodules) to take place. In the bath, it should be 3.7%–3.8% carbon to produce the product containing 3.5% carbon, as it is due to the loss taking place in solidification and in carbide formation.