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.

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.

The high-alloy irons can be categorized into two main groups: the high-alloy graphitic irons (covering both gray and ductile grades) and the high-alloy white irons. High-alloy irons are used in applications with demanding requirements, such as high resistance to wear, heat, and corrosion, or for combined properties. This article discusses the specification and selection of high-alloy irons. The common alloying elements and their effect on the stable and metastable eutectic temperatures are listed in a table. The article provides information on the compositions, properties and applications of high-alloy graphitic irons and high-alloy white irons.

Alloy cast irons are casting alloys based on the Fe-C-Si system that contain one or more alloying elements added to enhance one or more useful properties. This article discusses the composition of different types of alloy cast iron, including white cast irons, corrosion-resistant cast irons, heat-resistant cast irons, and abrasion-resistant cast irons. It provides information on the effect of the alloying element on their high-temperature properties. The article also discusses the microstructure and mechanical properties of alloy cast irons.

Castability of alloys is a measure of their ability to be cast to a given shape with a given process without the formation of cracks/tears, pores/shrinkage, and/or other significant casting defects. This article discusses the factors which affect the fluidity of an iron melt: alloy composition and initial melt condition. Besides the basic alloy properties, the effective castability of high-alloy irons can be significantly improved through casting and casting system design. The article describes the product design and processing factors of high-alloy graphitic irons and high-alloy white irons. It explains the heat treatment of high-silicon irons for high-temperature service and concludes with a discussion on machining and finishing of high-alloy iron castings.

This article discusses some of the factors that are linked directly to the casting design of ductile iron castings. It reviews the choice of molding process, application of draft, and patternmaker's allowance that should be taken into consideration in designing castings. The article describes the solidification shrinkage associated with the volume change that occurs during solidification, as well as strength and stiffness of ductile iron castings. It concludes with a discussion on the thermal deformation and residual stress in ductile iron castings.

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.

This article discusses the five basic matrix structures in cast irons: ferrite, pearlite, bainite, martensite, and austenite. The alloying elements, used to enhance the corrosion resistance of cast irons, including silicon, nickel, chromium, copper, molybdenum, vanadium, and titanium, are reviewed. The article provides information on classes of the cast irons based on corrosion resistance. It describes the various forms of corrosion in cast irons, including graphitic corrosion, fretting corrosion, pitting and crevice corrosion, intergranular attack, erosion-corrosion, microbiologically induced corrosion, and stress-corrosion cracking. The cast irons suitable for the common corrosive environments are also discussed. The article reviews the coatings used on cast irons to enhance corrosion resistance, such as metallic, organic, conversion, and enamel coatings. It explains the basic parameters to be considered before selecting the cast irons for corrosion services.

Alloy cast irons are considered to be those casting alloys based on the iron-carbon-silicon system that contain one or more alloying elements intentionally added to enhance one or more useful properties. Alloy cast irons can be classified as white cast irons, corrosion-resistant cast irons, and heat-resistant cast irons. This article discusses abrasion-resistant chilled and white irons, high-alloy corrosion-resistant irons, and medium-alloy and high-alloy heat-resistant gray and ductile irons. The article outlines in a list the approximate ranges of alloy content for various types of alloy cast irons. The article explains the effects of alloying elements and the effects of inoculants. In most cast irons, it is the interaction among alloying elements that has the greatest effect on properties. Inoculants other than appropriate graphitizing or nodularizing agents are used rarely, if ever, in high-alloy corrosion-resistant or heat-resistant irons.

Cast irons provide excellent resistance to a wide range of corrosion environments when properly matched with that service environment. This article presents basic parameters to be considered before selecting cast irons for corrosion services. Alloying elements can play a dominant role in the susceptibility of cast irons to corrosion attack. The article discusses the various alloying elements, such as silicon, nickel, chromium, copper, and molybdenum, that enhance the corrosion resistance of cast irons. Cast irons exhibit the same general forms of corrosion as other metals and alloys. The article reviews the various forms of corrosions, such as graphitic corrosion, fretting corrosion, pitting and crevice corrosion, intergranular attack, erosion-corrosion, microbiologically induced corrosion, and stress-corrosion cracking. It discusses the four general categories of coatings used on cast irons to enhance corrosion resistance: metallic, organic, conversion, and enamel coatings.

Cast irons primarily are iron alloys that contain more than 2% carbon and from 1 to 3% silicon. This article provides a description of iron-iron carbide-silicon system; and discusses the classification, composition, and characteristics of cast irons, such as gray, ductile, malleable, compacted graphite, and white cast iron. A table shows the correspondence between commercial and microstructural classification, as well as final processing stage in obtaining common cast irons.

The cast iron family includes several different groups, including gray iron, ductile iron, compacted graphite iron, malleable iron, white iron, and many different grades within each of these alloy groups. This article addresses issues specific to gray iron, but in many instances the discussion can be related to the other cast iron groups and the various grades within those groups. It discusses the usage of techniques and procedures in cast iron fractography. The article presents a list of common defects that can initiate failure.

This article discusses the compositions, properties, and typical applications for ductile irons that are defined by U.S. and international standards . It describes the various methods used to test and inspect the metallurgical control processes in ductile iron production. The article discusses the effect of composition, graphite shape, and section size on the properties of ductile iron. The article also describes the mechanical properties of ductile iron at elevated temperatures. The heat treatment of ductile iron castings produces a significant difference in mechanical properties from as-cast ductile iron. A ductile iron generally has higher hardenability than a eutectoid steel with comparable alloy content. The article also discusses the physical properties of ductile iron, including density, thermal conductivity, electrical conductivity, electrical resistivity, and magnetic properties. Ductile iron has been chosen in many instances on the basis of significantly lower machining costs, which resulted in lower overall cost of the part.

This article provides information on the general characteristics, composition, uses, applications and specifications for standard grades of ductile iron. It describes the manufacturing and metallurgical process control procedures, including testing and inspection, and heat treatment. The article also talks about the effects of composition, graphite shape, and section size on the mechanical properties of ductile iron. Tables and graphs provide helpful information on the tensile properties, compressive properties, torsional properties, damping capacity, impact properties, fracture toughness, fatigue strength, and elevated-temperature properties of ductile iron.

The mechanical properties of ductile cast irons are determined largely by the microstructure of the steel matrix in combination with the shape, size, and distribution of the graphite nodules. This article describes the designation of ductile cast irons according to the ASTM International designation system and reviews standard-grade ductile cast irons. An overview of the most commonly used standards related to designation and specification of ductile cast iron is presented in a table. This article discusses the use of low-alloy ductile cast irons at elevated temperatures and the chemical compositions and some mechanical properties of austenitic ductile cast irons. The article concludes with a discussion on heat treatment of austempered ductile iron.

Austempered ductile iron (ADI) results from a specialty heat treatment of ductile cast iron. This article discusses the production of austempered ductile iron by heat treatment. The austempered ductile iron grades, according to ISO 17804 and EN 1564, are presented in a table. For economic reasons, or to avoid metallurgical problems, combinations of alloys are often used to achieve the desired hardenability in austempered ductile iron. The article provides information on the alloy combinations for austempered ductile iron. The mechanical properties, fracture toughness, fatigue, and abrasion resistance of the austempered ductile iron are discussed. The article concludes with information on the applications for austempered ductile iron.

This article discusses criteria that can be used for the classification of cast iron: fracture aspect, graphite shape, microstructure of the matrix, commercial designation, and mechanical properties. It addresses the main factors of influence on the structure of cast iron, including chemical composition, cooling rate, and heat treatment. The article describes some basic principles of cast iron metallurgy. It discusses the main effects of the chemical composition of ductile iron and compacted graphite (CG) iron. The composition of malleable irons must be selected in such a way as to produce a white as-cast structure and to allow for fast annealing times. Some typical compositions of malleable irons are presented in a table. The article concludes with information on special cast irons.

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.

Cast irons, like steels, are iron-carbon alloys but with higher carbon levels than steels to take advantage of eutectic solidification in the binary iron-carbon system. This article introduces the solid-state heat treatment of iron castings and describes the various processes of heat treatment of cast iron. It provides information on stress relieving, annealing, normalizing, through hardening, and surface hardening of these castings. The article discusses general considerations for the heat treatment of cast iron. Cast irons are occasionally nitrided for various applications with the aim of enhancing surface hardness and corrosion resistance of the products. The article describes molten salt bath cyaniding and ion nitriding of cast iron.

The term cast iron designates a group of materials that contain more than one constituent in their microstructure due to excess carbon that result in unique characteristics such as the fracture appearance and graphite morphology. This article discusses the classification of cast iron and the various metallurgical aspects, such as the composition, alloying element, solidification, and graphite morphologies, of different types of cast iron. It describes the physical properties for various cast irons and the influence of microstructure and chemical composition on each property. The article provides a detailed account on thermal properties, conductive properties, magnetic properties, and acoustic properties of cast iron. It also examines heat treatment, namely, stress relieving, annealing, normalizing, through hardening, and surface hardening. The article presents a discussion on the welding, machining and grinding, and coating of the types of cast iron.