Search Results for stack melters

This article illustrates the basic components of dry and wet hearth reverberatory furnaces. It discusses stack melters that are used for aluminum metal casting, as they are efficient in sealing the furnace and using the flue gases to preheat the charge materials. The article describes the various factors for improving and maintaining furnace efficiencies. It explains the benefits of circulating molten metal in reverberatory furnaces and circulation methods.

Dross, which is the oxide-rich surface that forms on melts due to exposure to air, is a term that is usually applied to nonferrous melts, specifically the lighter alloys such as aluminum or magnesium. This article describes dross formation and ways to reduce it, the economic implications of dross, and in-plant enhancement or recovery of dross. It discusses the influence of the melter type on dross generation and the influence of charge materials and operating practices on melt loss. Fluxing is a word applied in a broad sense to a number of melt-treating methods. The article also discusses the in-furnace treatment with chemical fluxes.

Aluminum possesses many characteristics that make it highly compatible with recycling. Production of aluminum from scrap has a number of advantages. This article discusses the technology for the recovery, sorting, and remelting of aluminum. It describes the collection and acquisition of aluminum scrap in transportation, packaging, electrical and electronic, and building and construction sectors. The article reviews the technologies used to accomplish comminution for aluminum: shearing, knife shredding, and swing-hammer shredding. It provides a description of the devices used in scrap sorting, such as hand sorting, air classification, magnetic separation, eddy-current separation, heavy-media separation, and sensor-based sorting. The article also describes thermal processing, refining and casting, and dross processing of aluminum. It provides information on reverberatory and electric furnaces used for melting aluminum.

The large majority of the commercially important glasses are processed from a carefully calculated batch of raw materials that is then melted in special furnaces. Providing an introduction to melting practices of glass production, this article focuses on various finishing methods of glass products, including forming, grinding and polishing, and explores the advantages, disadvantages and steps involved in sol-gel process. It also discusses the types, processes and properties of annealed, laminated, and tempered glass, and presents the steps involved in glass decoration. The article gives a detailed account of production, properties and application of fiberglass, optical fibers, glass spheres and ceramic glasses, and describes the forms, classification, compositions and properties of glass/metal and glass-ceramic/metal seals.

The historical use of induction heating relating to glass melting gives some insight into its use in today's glass manufacturing industry. A patent search on induction heating provides historical information about how induction heating was used in the glass melting industry, from both a direct fired or a susceptor/container approach. This article provides review of historical patents, following an introduction to conductivity in glass and electrical heating. The purpose is to show that induction heating has been and is being used in the glass melting industry.

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.

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.

Many nonferrous metals, including aluminum, nickel, copper, and others, are among the few materials that do not degrade or lose their chemical or physical properties in the recycling process. As a result, these metals can be recycled an infinite number of times. This article focuses on the recycling of nonferrous alloys, namely, aluminum, copper, magnesium, tin, lead, zinc, and titanium, providing details on the sources, consumption and classification of scrap, and the technological trends and developments in recycling.

Structural applications for advanced ceramics include mineral processing equipment, machine tools, wear components, heat exchangers, automotive products, aerospace components, and medical products. This article begins with an overview of the wear-resistant applications and the parameters affecting wear of ceramics, namely, hardness, thermal conductivity, fracture toughness, and corrosion resistance. The next part of the article addresses temperature-resistant applications of advanced ceramics. Specific applications of ceramic materials addressed include cutting tools, pump and valve components, rolling elements and bearings, paper and wire manufacturing, biomedical implants, heat exchangers, adiabatic diesel engines, advanced gas turbines, and aerospace applications.

Vacuum induction melting (VIM) is often done as a primary melting operation followed by secondary melting (remelting) operations. This article presents the process description of VIM and illustrates potential processing routes for products, which are cast from VIM ingots or electrodes. It describes the VIM refinement process, which includes the removal of trace elements, nitrogen and hydrogen degassing, and deoxidation. The article concludes with information on the production of nonferrous materials by VIM.

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.

There are a wide variety of furnace types and designs for melting aluminum. This article discusses the various types of furnaces, including gas reverberatory furnaces, crucible furnaces, and induction melting furnaces. It describes the classification of solid fluxes: cover fluxes, drossing fluxes, cleaning fluxes, and furnace wall cleaner fluxes. The article reviews the basic considerations in proper flux selection and fluxing practices. It explains the basic principles of degassing and discusses the degassing of wrought aluminum alloys. The article describes filtration in wrought aluminum production and in shape casting. It also reviews grain refinement in aluminum-silicon casting alloys, aluminum-silicon-copper casting alloys, aluminum-copper casting alloys, aluminum-zinc-magnesium casting alloys, and aluminum-magnesium casting alloys. The article concludes with a discussion on aluminum-silicon modification.

This article begins with an overview of the fundamentals of adhesive technology, including functions, limitations, adhesive joint types, and the key factors in the selection of adhesives, including application, type of joint, process limitation, mechanical requirement, and service conditions. It then focuses on the characteristics, types, and properties of the five groups of adhesives, such as structural, hot melt, pressure sensitive, water based, ultraviolet, and electron beam cured adhesives. The article also discusses the functions and applications of adhesive modifiers, including fillers, adhesion promoters, tackifiers, and tougheners. It gives a short note on functions of primers and primerless bonding. Applications of adhesives in automotive, aerospace, electronics, electrical, medical, sports, and construction sectors are also described. Finally, the article describes the steps in adhesive bonding, including storage and handling of adhesives, bonding preparation, adhesive application, tooling, and curing.

This article presents a detailed account on the process flow, composition, alternative sources, and the advancement of ironmaking, steelmaking and secondary steelmaking practices. Some steels, such as bearing steels, heat-resistant steels, ultrahigh strength missile and aircraft steels, and rotor steels have higher quality requirements and tighter composition control than plain carbon or ordinary low-alloy steels. The production of special-quality steels requires vacuum-based induction or electric remelting and refining capabilities. The article explores the types and characteristics of various steel manufacturing processes, such as ingot casting, continuous casting, and hot rolling. It provides an outline of specialized processing routes of producing ultralow plain carbon steels, interstitial-free steels, high strength low-alloy steels, ultrahigh strength steels, stainless steels, and cold-rolled products, and briefly explains the analytical techniques for liquid steels.

This article describes ironmaking and steelmaking practices (melt or liquid processing, including hot metal desulfurization) and discusses the evolution of these processes and their effects on steel properties. The physical chemistry of steelmaking may appear deceptively simple for integrated steel mill operations where ore from the ground is converted into steel. The various refining steps that occur in steelmaking are reviewed. The article also describes solid processing of steel, with emphasis on hot and cold rolling, thermomechanical processing, and annealing of flat steel products.

This article presents a detailed discussion on the microstructures, physical metallurgy, classification, deformation behavior, and fracture modes of titanium alloys. It illustrates the effect of microstructure and texture on the fracture topography and fracture behavior of titanium alloys with a variety of relevant examples.