Thread rolling is a cold-forming process for producing threads or other helical or annular forms by rolling the impression of hardened steel dies into the surface of a cylindrical or conical blank. Methods that use cylindrical dies are classified as radial infeed, tangential feed, through feed, planetary, and internal. This article focuses on the capabilities, limitations, and machines used for these methods. It describes the three characteristics, such as rollability, flaking, and seaming, used in evaluating and selecting metals for thread rolling. The article explores the factors affecting die life and explains the effect of thread form on processing. It provides information on various fluids used in thread rolling to cool the dies and the work and to improve the finish on the rolled products. The article provides a comparison between thread rolling and cutting, as well as between thread rolling and grinding.

The properties of irons and steels are linked to the chemical composition, processing path, and resulting microstructure of the material. For a particular iron and steel composition, most properties depend on microstructure. Processing is a means to develop and control microstructure, for example, hot rolling, quenching, and so forth. This article describes the role of these factors in both theoretical and practical terms, with particular focus on the role of microstructure. It lists the mechanical properties of selected steels in various heat-treated or cold-worked conditions. In steels and cast irons, the microstructural constituents have the names ferrite, pearlite, bainite, martensite, cementite, and austenite. The article presents four examples that have very different microstructures: the structural steel has a ferrite plus pearlite microstructure; the rail steel has a fully pearlitic microstructure; the machine housing has a ferrite plus pearlite matrix with graphite flakes; and the jaw crusher microstructure contains martensite and cementite.

Cast iron exhibits a considerable amount of eutectic in the solid state. This article discusses the structure of liquid iron-carbon alloys to understand the mechanism of the solidification of cast iron. It illustrates nucleation of the austenite-flake graphite eutectic, austenite-spheroidal graphite eutectic, and austenite-iron carbide eutectic. The article provides a discussion on primary austenite and primary graphite. Depending on the carbon equivalent, the primary phase in cast iron can be either austenite for hypoeutectic cast iron or graphite for hypereutectic cast iron. The article also describes the growth of eutectic in cast iron in terms of isothermal solidification, directional solidification, and multidirectional solidification.

The International Committee of Foundry Technical Associations has identified seven basic categories of casting defects: metallic projections, cavities, discontinuities, defective surfaces, incomplete casting, incorrect dimension, and inclusions or structural anomalies. This article presents some of the common defects in each of the seven categories in a table. It also discusses select case studies relevant to inclusions, cavities (gas porosity, shrinkage), and discontinuities (hot tearing, cold shut).

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.

This article is an atlas of fractographs that helps in understanding the causes and mechanisms of fracture of gray irons and in identifying and interpreting the morphology of fracture surfaces. The fractographs illustrate the fatigue fracture, solidification structure, and crack propagation of gray irons.

This article provides information on the classification, microstructure, castability and section sensitivity of gray iron. It describes properties of the test bar and provides a short note on fatigue limit in reversed bending. Although the ASTM size B test bar is the bar most commonly used for all gray irons from classes 20 to 60, ASTM A 48 provides a series of bar sizes, and the user can select the bar sizes that best approximates the cooling rate in the critical section of the casting.

This article discusses the graphite morphology, chemical composition, mechanical and physical properties, and applications of compacted graphite (CG) irons. It compares the selected properties of gray, ductile and CG irons, and lists their property requirements as per ASTM A 842. A listing of tensile properties of various CG irons produced by different melt treatment methods is also provided.

This article reviews the graphite morphology, chemical composition requirements, castability, mechanical properties, and corrosion resistance of compacted graphite (CG) irons. It describes the factors affecting the mechanical properties of CG irons. The article also presents the advantages of the CG irons.

An understanding of the influence of microstructure on machinability can provide an insight into more efficient machining and the correct solution to problems. Providing numerous microstructures to depict examples, this article describes the relationship between the microstructure and machinability of cast irons, steels, and aluminum alloys. It presents data on hardness values and the effect of the matrix microstructure of cast iron on tool life. It also explains how a higher inclusion count improves the machinability of steels and why aluminum alloys can be machined at very high speeds.

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 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 discusses 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.

This article discusses postconsumer plastics recyclate quantities, the classification of plastics recycling into primary, secondary, tertiary, and quaternary categories, and how the life cycle of plastics is affected by recycling. The recycling processes of polyethylene terephthalate (PET), which accounts for the largest percentage of plastic recycling, high-density polyethylene (HDPE) plastics, the other large-volume plastic recyclate, as well as vinyl resins and polycarbonate resins are described. The life cycle of plastics has four phases: poly formation, part fabrication, product service, and disposal. Landfilling is still the primary method of final disposal, and incineration is another option, but recycling has become a viable alternative. The article presents a comparison between secondary and tertiary recycling.

This article begins with an overview of classes and applications of gray iron. It discusses the castability of gray iron in terms of section sensitivity and fluidity. The article provides information on the dimensions of prevailing sections recommended for gray irons and reviews the properties and specifications of test bar. It discusses the properties of gray iron, such as fatigue limit, pressure tightness, impact resistance, machinability, and dimensional stability, at both room and elevated temperature. Wear behavior of gray iron castings during sliding contact under conditions of normal lubrication is also discussed. The article reviews the use of alloys and heat treatment to modify as-cast properties. It concludes with information on physical properties of gray iron castings.

The commonly used nondestructive testing of cast products include liquid penetrant inspection, radiographic inspection, fluoroscopic inspection and automated defect recognition, ultrasonic inspection, eddy current inspection, process-controlled resonant testing (PCRT), leak test, and electrical conductivity measurements. This article summarizes the application of these nondestructive tests to castings. It also tabulates a partial list of automotive part types and materials amenable to PCRT and lists the potential limitations to the use of PCRT.

Molten salt baths are anhydrous, fused chemical baths used at elevated temperatures for a variety of industrial cleaning applications. This article discusses their applications in paint stripping, polymer removal, casting cleaning, glass removal, and plasma/flame spray removal. It provides an overview of the basic design and safety considerations of the salt bath equipment and describes the environmental impact of molten salt bath cleaning.

This article illustrates equilibrium phase diagram for the aluminum-silicon system showing metastable extensions of the liquidus and solidus lines. It describes the classification and microstructure of the aluminum-silicon eutectic. The article presents the theories of solidification and chemical modification of the aluminum-silicon eutectic.

This article provides a discussion on polyester coating applications such as powder coatings, can coatings, and automotive paints. It includes an overview, structure, properties, and benefits of vinyl ester resins. The article discusses the additives for both unsaturated polyester and vinyl ester coatings, namely, curing systems, thixotropic agents and fillers. It exemplifies polyester and vinyl ester coating, lining and flooring systems that are used for top-to-bottom protection of industrial plants and equipment. The article also highlights the concerns to be addressed when using polyesters and vinyl esters.

Coatings, such as those applied to ships, must be resistant to abrasion, in the case of cargo hold coatings, and cyclic changes of chemicals and tank cleaning, in the case of tank linings. Failures and defects can manifest themselves at various times in the life of a coating. To determine the cause and mechanism of coating failure, all possible contributory factors must be evaluated together with a detailed history from the time of application to the time the failure was first noted. Many coating failures require further evaluation and analysis to be carried out by a qualified chemist or coating specialist, often using specialized laboratory equipment. The article presents examples of coating failures and defects, together with descriptions, probable causes, and suggested preventative measures.

This article discusses the types of squeeze-casting machines and the advantages of squeeze casting. It discusses the considerations required for the casting and tooling design process of squeeze casting. The article describes the various factors affecting the squeeze-cast products and outlines few of the key process characteristics. It provides information on the applications of squeeze-cast and contains a table that compares the tensile, hardness, and impact properties of select squeeze-cast aluminum alloys with those obtained from conventional casting processes.

This article provides background information on the chemistry, coating properties, resin types, applications techniques, and performance characteristics of fluoroethylene vinyl ether (FEVE) resins. It describes the formulation methods of FEVE resins, namely, solvent-based coating formulations, water-based coating formulations, and powder coating formulations. The basic concerns to be addressed when formulating and using FEVE coatings are also discussed. The article concludes with a section on health and related safety regulations.