Search Results for cupola equipment

In high-iron-tonnage operations, the cupola remains the most efficient source of continuous high volumes of iron needed to satisfy high production foundries or the multiple casting machines of centrifugal pipe producers. This article explores successful improvement technologies in cupola equipment, including preheated air blast, recuperative hot blast systems, and duplex electric holders. It discusses the shell, intermittent or continuous tapping, tuyere and blower systems, refractory lining, water-cooled cupolas, emission-control systems, and storage and handling of the charge materials. The article provides a discussion on the control tests for cupola, including the chill test and mechanical test. It concludes with information on specialized cupolas such as the cokeless cupola and the plasma-fired cupola.

The melting process often includes refining and treating the metal. The choice of which type of melting to use depends on a number of factors: type of alloy being melted, the local cost of electric power, and local environmental regulations. This article discusses the principles, furnace types, charging practices of metal melting methods, namely induction melting, cupola melting, arc melting, crucible melting, reaction melting, and vacuum melting, and the refractories and charging practice of reverberatory furnaces. Molten metal treatment of steels and aluminum also is discussed in the article.

Various types of furnaces have been used for cast iron melting. In terms of tonnage, the primary melting methods used by iron casting facilities are cupola and induction furnaces. This article describes the operation and control principles of cupola furnace. It discusses the advantages of specialized cupolas such as cokeless cupola and plasma-fired cupola. Melting in iron foundries is a major application of induction furnaces. The article describes the operations of two induction furnaces: the channel induction furnace and the induction crucible furnace. It explains the teapot principle of pressure-actuated pouring furnaces and provides information on the effect of pouring magnesium-treated melts.

This article reviews the production stages of iron foundry casting, with particular emphasis on the melting practices, molten metal treatment, and feeding of molten metal into sand molds. It discusses the molten metal treatments for high-silicon gray, high-nickel ductile, and malleable irons. Foundry practices are also described for compacted graphite, high-silicon ductile, and high-alloy white irons.

Foundry practices critical to the production of cast irons include melting, alloying, molten metal treatment, pouring, and the design of feeding systems (gating and risering) to allow proper filling of the casting mold. This article reviews these production stages of iron foundry casting, with particular emphasis on the melting practices, molten metal treatment, and feeding of molten metal into sand molds. It discusses the castability factors, such as fluidity, shrinkage, and resistance, of gray iron. Typical cupola charge compositions and the final analyses for class 30 and class 40 gray iron castings are presented in a table. The article describes the induction melting and arc furnace melting used in gray iron foundries. It also reviews the inoculation methods such as stream inoculation and mold inoculation, of gray iron.

Casting is one of the most economical and efficient methods for producing metal parts. In terms of scale, it is well suited for everything from low-volume, prototype production runs to filling global orders for millions of parts. Casting also affords great flexibility in terms of design, readily accommodating a wide range of shapes, dimensional requirements, and configuration complexities. This article traces the history of metal casting from its beginnings to the current state, creating a timeline marked by discoveries, advancements, and influential events. It also lists some of the major markets where castings are used.

The crucible induction furnace is growing as an alternative melting unit to the cupola furnace due to its low specific power and reduced power consumption during solid melting material. This article details the process engineering features of the crucible induction furnace. It discusses the various processes involved in melting, holding, and pouring of liquid melt in crucible induction furnaces wherein the holding operation is carried out in channel furnace and pouring operation in pressure-actuated pouring furnaces. The article examines the behavior of furnace refractory lining to defects such as erosion, infiltration, crack formation, and clogging, and the corresponding preventive measures to avoid the occurrence of these defects. It elucidates the overall furnace operations, including commissioning, operational procedures, automatic process monitoring, inductor change, and dealing with disturbances.

Cast iron, which usually refers to an in situ composite of stable eutectic graphite in a steel matrix, includes the major classifications of gray iron, ductile iron, compacted graphite iron, malleable iron, and white iron. This article discusses melting, pouring, desulfurization, inoculation, alloying, and melt treatment of these major ferrous alloys as well as carbon and alloy steels. It explains the principles of solidification by describing the iron-carbon phase diagram, and provides a pictorial presentation of the basic microstructures and processing steps for cast irons.

Malleable iron possesses considerable ductility and toughness because of its combination of nodular graphite and a low-carbon metallic matrix. The desired formation of temper carbon in malleable irons has two basic requirements. First, graphite should not form during the solidification of the white cast iron, and second, graphite must also be readily formed during the annealing heat treatment. These two metallurgical requirements influence the useful compositions of malleable irons and the melting, solidification, and annealing procedures. There are two basic types of malleable iron: blackheart and whiteheart. This article considers only the blackheart type and describes the metallurgical factors of malleable iron. It discusses the mechanical properties of pearlitic and martensitic malleable irons. The article provides additional information on the properties and heat treatment of ferritic, pearlitic, and martensitic malleable irons. The article lists some of the typical applications of malleable iron castings.

Unlike gray iron, which contains graphite flakes, ductile iron has an as-cast structure containing graphite particles in the form of small, rounded, spheroidal nodules in a ductile metallic matrix. This article discusses the raw materials that are used for ductile iron production and outlines the most common and important requirements for controlling the composition of ductile iron. Treatment to produce ductile iron involves the addition of magnesium to change the form of the graphite, followed by or combined with inoculation of a silicon-containing material to ensure a graphitic structure with freedom from carbides. The article describes the methods of magnesium treatment, control of magnesium content, and inoculation. It concludes with a discussion on the metallurgical controls of ductile iron production.

Malleable iron is a cast ferrous metal that is initially produced as white cast iron and is then heat treated to convert the carbon-containing phase from iron carbide to a nodular form of graphite called temper carbon. This article provides a discussion on the melting practices, heat treatment, microstructure, production technologies, mechanical properties, and applications of ferritic, pearlitic, and martensitic malleable irons.

Malleable iron, like ductile iron, possesses considerable ductility and toughness because of its combination of nodular graphite and low-carbon metallic matrix. This article discusses melting practices such as batch cold melting and duplexing, and their control mechanisms. It schematically illustrates the microstructure of annealed ferritic malleable iron, which is characterized by microstructures consisting of uniformly dispersed fine particles of free carbon in a matrix of ferrite or tempered martensite. The article describes the digital solidification analysis technology, simulation technologies, and smart engineering for the production of malleable iron. It provides information on the applications of ferritic and pearlitic malleable irons.

This article describes the principles and classifications of induction furnaces. The classifications of induction furnaces are coreless and channel. The electromagnetic stirring action in these furnaces is reviewed. The article provides information on the various power supplies and water cooling systems for induction furnaces. Furnace operators can increase the power supply utilization by the use of mechanical skimmers. The article describes the various lining materials used in induction furnaces, namely, silica, alumina, and magnesia. The crucible wall scrapers, ramming mixes, and lining push-out device used in induction furnaces are also reviewed. The article concludes with a discussion on batch operation and tap-and-charge operation, two distinct ways of operating a coreless induction furnace.

This article discusses the melting and pouring practices, heat treatment, and applications of different types of high-alloy graphitic iron, namely, high-silicon gray irons, high-silicon ductile irons, nickel-alloyed austenitic irons, austenitic gray irons, austenitic ductile irons, and aluminum-alloyed irons.

Tin is a soft, brilliant white, low-melting metal that is most widely known and characterized in the form of coating. This article discusses the primary and secondary production of tin and explains the uses of tin in coating, namely tinplating, electroplating, and hot dip coatings. It presents a short note on pure (unalloyed) tin and uses of tin in chemicals. The article also covers the compositions and uses of tin alloys which include solders, pewter, bearing alloys, alloys for organ pipes, and fusible alloys. It goes on to discuss the other alloys containing tin including battery grid alloys, type metals, copper alloys, dental alloys, cast irons, titanium alloys, and zirconium alloys. Finally, it presents a short note on the applications of tin powder and corrosion resistance of tin.

This article summarizes some general alloy groupings by application or major characteristics. The groupings include cast rotor, general-purpose, elevated-temperature, wear-resistant, moderate-strength, high-strength, and high-integrity die casting alloys and cast aluminum alloys bearings. A table lists selected applications for aluminum casting alloys.

This article focuses on the construction, operation of electric arc furnaces (EAF), and their auxiliary equipment in the steel foundry industry. It provides information on the power supply of EAF and discusses the components of the EAF, including the roof, furnace shell, spout and tap hole, water-cooling system, preheat and furnace scrap burners, and ladles. The article describes the acid and basic steelmaking practices. It discusses the raw materials used, oxidation process, methods of heat reduction, and deoxidation process in the practices. The article provides a discussion on the arc melting of iron and EAF steelmaking.

This article provides a short time travel of the evolution of cast iron from witchcraft to virtual cast iron, a road paralleled by the gigantic stride from a low-quality, corrupt metal to the high-tech material that it is today. It presents a chronological list of developments and use of cast iron during prehistory, antiquity, and the medieval ages in a table. The earliest successful iron founding is generally credited to the ancient Mesopotamian civilizations many centuries before Christ. The article discusses the evolution of early cast iron in Mesopotamia and China, as well as in Europe in the medieval ages. It provides information on the applications of cast iron as a high-tech, economical, and modern material.

Plasma melting is a material-processing technique in which the heat of thermal plasma is used to melt a material. This article discusses two typical design principles of plasma torches in the transferred mode: the tungsten tip design and the hollow copper electrode design. It describes the sources of atmospheric contamination in plasma melting furnaces and their control measures. The equipment used in plasma melting furnaces are also discussed. The article provides a detailed discussion on various plasma melting processes, such as plasma consolidation, plasma arc remelting, plasma cold hearth melting, and plasma casting.

A significant amount of the worldwide demand for metals is met with recycled materials acquired by metal producers in the form of purchased scrap. This article focuses primarily on the methods and technology used to process and repurpose the vast amounts of purchased scrap that recirculate in the industrial supply chain. It describes the U.S. market for iron and steel scrap, providing information on scrap use by industry, factors influencing demand, and the purchased scrap supply. Iron and steel recycling is discussed separately from stainless steel and superalloy recycling in this article, as the scrap industry treats them differently. The scrap processing of iron involves collection, separation and sorting, size reduction and compaction, detinning, blending, and incineration. The recycling of stainless steels and superalloys follows the same process, but requires several additional steps, including secondary nickel refining, degreasing, and separation of metallurgical wastes.