Search Results for high-iron-tonnage operation

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 describes the various types of press construction and the factors that influence the selection of mechanically or hydraulically powered machines for producing parts from sheet metal. Presses are broadly classified, according to the type of frame used in their construction, into two main groups: gap-frame presses and straight-side presses. The article describes the various components of mechanical presses and hydraulic presses. It discusses important factors, such as the size, force, energy, and speed requirements, that influence the selection of a press. The article describes the roles of automatic handling equipment that can be categorized as feeding equipment, unloading equipment, and transfer equipment. It concludes with information on the common types of high-production presses, such as dieing machines, multiple-slide machines, transfer presses, fine blanking presses, and flexible-die forming presses.

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.

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 discusses different factors for selecting progressive dies: costs, production volume, and press availability. It describes the purposes of strip development for a ring shaped part and presents the principles for the development of progressive dies. The article provides discussions on the general design features of progressive dies and the choice of proper auxiliary equipment such as coil feeders and scrap handling equipment. It concludes with information on different presses for progressive die work: open-back inclinable presses, four-column presses, and automatic underdrive presses.

The morphology of the graphite particles in compacted graphite iron (CGI) is intermediate to the graphite particles found in gray iron or ductile iron. This article discusses the castability and product design of compacted graphite iron. The introduction of modern measurement and control technologies has made CGI a viable material for high-volume series production. The article describes the production of compacted graphite iron castings and the process control that depends on the production volume of components made from compacted graphite iron. It also discusses the process control for high-volume CGI commonly based on thermal analysis.

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.

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 provides a detailed account on forming operations (blanking, piercing, press-brake forming, contour rolling, deep drawing, cold forming, and hot forming) of various nonferrous metals, including aluminum alloys, beryllium, copper and its alloys, magnesium alloys, nickel alloys, titanium alloys, and platinum metals. It discusses the formability, equipment and tooling, and lubricants used in the forming operations of these nonferrous metals.

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.

This article discusses the most important factors required for cutoff methods. It explains the operations of machines used for the punching, shearing, notching, or coping of plates, bars, and structural sections. The article describes the effects of the blade angle and speed on the shear blade life. It reviews the design requirements and best practices for the production of blades. The article compares double-cut dies with single-cut dies used for shearing of structural and bar shapes. The shearing of specific forms, such as angle iron and flat stock, is also discussed. The article describes the advantages of hydraulic bar and structural shears. It concludes with information on the principle and construction of impact cutoff machines.

High-alloy graphitic cast irons are used primarily in applications requiring corrosion resistance or strength and oxidation resistance in high-temperature service. This article describes the properties, applications and heat treatment processes of high-alloy graphitic cast irons, including austenitic gray irons and austenitic ductile irons. It also provides a discussion on the heat treatment of high-silicon irons for heat resisting and corrosion resisting applications.

Arc welding is one of several fusion processes for joining metals. This article introduces the fundamentals of arc welding and provides a summary of its history and early discoveries.

Mechanical cleaning systems are used to remove contaminants of work surface by propelling abrasive materials through any of these three principal methods: airless centrifugal blast blade- or vane-type wheels; compressed air, direct-pressure dry blast nozzle systems; or compressed-air, indirect-suction (induction) wet or dry blast nozzle systems. This article focuses on the abrasive media, equipment, applications, and limitations of dry and wet blast cleaning. It discusses the health and safety precautions to be taken during mechanical cleaning.

Thermal spray is an important surface-modification process implemented by the steel industry. This article reviews thermal spray materials and equipment used and also provides examples of where typical coated components result in improved performance. It contains a table that lists thermal spray applications in the iron-steel manufacturing industry.

This article discusses the fundamentals of broaching, including broach tooth terminology, broach cutting action, and broach size. It describes two types of broaching machines: horizontal and vertical. The article illustrates three general categories of broaches: solid, shell, and insert-type. It tabulates feeds and speeds for broaching various steels with high-speed tool steels and carbide tools. The article also describes the advantages and limitations of broaching and provides a brief discussion on burnishing. The causes and prevention of broach breakage are also discussed. The article concludes with information on broach repair.

This article illustrates the mechanics of the deep drawing of a cylindrical cup. It discusses the fundamentals of drawing and drawability. Sheet metal is drawn in either hydraulic or mechanical presses. The article summarizes the defects in drawing and factors considered in press selection for drawing. It explains the types of dies used for drawing sheet metal and the effects of process variables and material variables on deep drawing. The process variables that affect the success or failure of a deep-drawing operation include the punch and die radii, punch-to-die clearance, press speed, lubrication, and type of restraint of metal flow used. The article describes the process of redrawing and ironing of metals. Drawing of workpieces with flanges and drawing of hemispheres are also illustrated. The article also provides information on the reducing of drawn shells, methods for expanding portions of drawn workpieces, trimming, and deep drawing using fluid-forming presses.

Dual-phase steels are a new class of high-strength low alloy (HSLA) steels characterized by a microstructure consisting of about 20% hard martensite particles dispersed in a soft ductile ferrite matrix. In addition to high tensile strength, in the range of 550 MPa (80 ksi), dual-phase steels exhibit continuous yielding behavior, a low 0.2% offset yield strength, and a higher total elongation than other HSLA steels of similar strength. The article discusses some of the more pertinent aspects of dual-phase steels, such as heat treatment, microstructure, mechanical properties, chemical composition, and manufacturability. In general, these steels have a carbon content of less than 0.1%, which ensures that they can be spot welded. However, newer high-carbon dual-phase steels in development are generating interest due to their unique combination of total elongation and tensile strength.