Coextrusion is defined as the simultaneous extrusion of two or more metals to form an integral product that can be carried out using conventional extrusion or drawing equipment at a temperature appropriate to the metal system being formed. This article discusses the applications, billet configurations, and metal flow modes of coextrusion. It presents the analytical studies of coextrusion: deformation energy methods, lower-bound (slab) analyses, upper-bound analyses, and finite-element analyses. These studies are used to identify the regime of material properties and process variables for which sound extrusions can be obtained. The article concludes with a discussion on the state-of-the-art of coextrusion that assists in developing process models, which accurately describe both the macroscopic and microscopic aspects of a process.

Forging of nickel-base alloys results in geometries that reduce the amount of machining to obtain final component shapes and involves deformation processing to refine the grain structure of components or mill products. This article discusses the heating practice, die materials, and lubricants used in nickel-base alloys forging. It describes two major forging processing categories for nickel-base alloys: primary working and secondary working categories. Primary working involves the deformation processing and conversion of cast ingot or similar bulk material into a controlled microstructure mill product, such as billets or bars, and secondary working refers to further forging of mill product into final component configurations.

This article describes the presses, transportation equipment, and manufacturing processes associated with cogging. It discusses the practical and metallurgical issues encountered during the conversion of ingot to billet. The article explains the use of numerical modeling as part of the continuing efforts to reduce the cost and time associated with developing new cogging sequences, increase the yield, make the processes more robust, and increase the quality of the produced product.

This article describes the mechanics and processing characteristics of equal-channel angular extrusion (ECAE). Tool design considerations for the ECAE are discussed. During ECAE, severe plastic strains and simple shear deformation mode contribute to strong, sometimes unusual effects of processing on structure and properties. The article explains these effects and concludes with a discussion on the applications of the ECAE.

This article discusses two basic forms of extrusion: cold and hot. It provides information on three types of extrusion processes, namely, direct extrusion, reverse extrusion, and hydrostatic extrusion. The article also discusses the mechanics, analysis, tooling and die design of extrusion as well as thermodynamics. The finite-element method suitable for simulation of metal forming processes is explained. The article examines the extrusion defects that are divided into three different categories including surface, subsurface, and internal type. It includes information on friction and lubrication modeling of extrusion processes. The article also discusses the fundamentals of extrusion technology of titanium alloys and aluminum. It concludes with information on two forms of wear in extrusion, namely, adhesive and abrasive wear.

This article describes the direct hot extrusion process and the typical sequence of operations for producing extruded aluminum shapes from soft and medium-grade aluminum alloys, hard alloys, and aluminum-matrix composites. It discusses key process variables, including extrusion speed and exit temperature, and their effect on product quality. The article also provides information on extrusion presses, press dies, and tooling, and addresses quality issues such as surface defects, blistering, and internal cracking. It concludes with a discussion on the drawing of solid section and aluminum tube.

Radial forging is a process performed with four dies arranged in one plane that can act on a piece simultaneously. This article explains the types of radial forgings and describes the advantages and disadvantages of radial forging over open-die cogging/forging. The article discusses the parameters involved in product shape control. It also provides examples that illustrate the versatility and capabilities of the radial forge machine.

Induction heating system control is straightforward after the design and application of the coil and power supply required for the job. This article provides an overview of the basic components of an induction heating system, including a machine controller (computer or programmable logic controller), interface wiring, an operator interface, and safety controls. It also provides information on programming devices and temperature controllers, such as manual, auto, and auto-manual temperature controllers.

The handling of billets or bars is an essential part of an induction heating system. This article describes two types of handling systems available for bar heating lines: inclined ramps with escapement, and sling feeder with inclined ramp and escapement. It focuses on the various infeed billet handling systems such as bin tippers, elevator feeders, rotary feeders, vibratory bowl feeders, magazine loaders, and rod feeders. The article provides information on the main categories of billet feeding systems, namely, dual pinch roll drive assemblies, tractor drive assemblies, billet pusher systems, walking beam assemblies, and index/continuous conveyor systems. It also discussed the hot billet handling systems used to deliver heated billets to the forging cell. These methods include billet extractor conveyors, accept/reject systems with pyrometer measurements, extractor rolls, discharge chutes, pinch roll extractors, pick-n-place systems, and robots.

Hot extrusion is a process in which wrought parts are formed by forcing a heated billet through a shaped die opening. This article discusses nonlubricated and lubricated hot extrusion. The two nonlubricated hot extrusion methods are forward or direct extrusion and backward or indirect extrusion. The article illustrates the significance of extrusion speeds and temperatures in hot extrusion. It describes the basic types of presses used in the hot extrusion of metals. The article provides information on the characterization of extruded shapes and explains the operating parameters, including extrusion velocity, amount of pressure required, and type of lubricant, for successful and efficient hot extrusion. The article concludes with a discussion on applications and design methodology that provides insight into CAD/CAM of extrusion dies.

The purpose of continuous casting is to bypass conventional ingot casting and to cast to a form that is directly rollable on finishing mills. The use of this process has resulted in improvement in yield, surface condition, and internal quality of product when compared to the ingot-made material. This article outlines the advantages of steel continuous casting, along with its developments and challenges for improvement. It provides a general description of the continuous casting process and the design and layout of a continuous casting steelmaking facility. It reviews process enhancements such as near-net shape casting, tundish metallurgy, and pouring stream protection. The article discusses the use and capabilities of different molds for steel continuous casting, including thin-wall tube-type molds, solid molds, and plate molds. The article explains the methods for enhancing productivity and improving quality in steel continuous casting. It evaluates the applications of horizontal continuous casting in casting steel. The article concludes by outlining priorities for future development such as enhanced control systems and automation.

This article focuses on nondestructive inspection of steel bars. The primary objective in the nondestructive inspection of steel bars and wire is to detect conditions in the material that may be detrimental to the satisfactory end use of the product. The article discusses various types of flaws encountered in the inspection of steel bars, including porosity, inclusions, scabs, cracks, seams, and laps. Inspection methods, such as magnetic-particle inspection. liquid penetrant inspection, ultrasonic inspection, and electromagnetic inspection, of steel bars are also described. The article provides a discussion on electromagnetic systems, eddy-current systems, and magnetic permeability systems for detection of flaws on steel bars. It concludes with a description of nondestructive inspection of steel billets.

This article focuses on forging processes and equipment, types of forging alloys, and the forging practices associated with the forging of copper and copper alloys. An overview of the forging tolerances for small copper-base forgings is presented in a table.

The drawing process, one of the oldest metal forming operations, allows excellent surface finishes and closely controlled dimensions to be obtained in long products that have constant cross sections. This article discusses the basic mechanics and preparation steps of drawing. It presents an overview of the processes, equipment, dies and die materials, and lubrication associated with drawing of rod, wire, bar, and tube. The article also provides a discussion on the design considerations and manufacturing of commercial superconducting multifilamentary conductors.

Machining serves as a more specialized supplement to the forging process, particularly in the formation of cavities and holes. This article provides information on the enclosures, cavities, and holes in hammer and press forgings. It provides a checklist that serves as a guide to the procedure for reviewing the design of cavities and holes to be incorporated in forgings. The article also describes forging designs in which cavities and holes are related to rib and web designs, punchout, piercing, extruding, and combinations of these processes.

Niobium-titanium alloys (NbTi) became the superconductors of choice in the early 1960s, providing a viable alternative to the A-15 compounds and less ductile alloys of niobium-zirconium. This can be attributed to the relative ease of fabrication, better electrical properties, and greater compatibility with copper stabilizing materials. This article discusses the ramifications of design requirements, selection criteria and processing methods of superconducting fibers and matrix materials. It provides information on the various steps involved in the fabrication of superconducting composites, including assembly, welding, isostatic compaction, extrusion, wire drawing, twisting, and final sizing. The article also provides a detailed account of the properties and applications of NbTi superconducting composites.

This article lists functions of lubricants common to the majority of applications and processes. It discusses the lubricant candidates widely used in forging: conversion coatings with soaps (stearate compounds) and molybdenum disulfide for cold forging; oil-based thick, film oil or polymerbased lubricants and molybdenum disulfide for warm application; graphite suspensions in oil or water for hot forging steels; and glass films for titanium and superalloys hot forgings. The article describes the applications of lubricants in warm extrusion and forging, hot forging of steel, hot forging of aluminum, isothermal and hot die forging, and the extrusion of steel.

Roll forging is a process for simultaneously reducing the cross-sectional area and changing the shape of heated bars, billets, or plates. This article provides an overview of the process capabilities, production techniques, machines and machine size selection considerations, and types of roll dies and auxiliary tools for the roll forging. It concludes with information on the production examples of roll forging.

This article is a compilation of best practices, materials, and techniques for the design and manufacture of modern induction forge coils. It presents the basics of induction coil design along with various design considerations, namely, copper tube selection, water flow considerations, and brazing and fabricating the copper coil winding for heating billets, bars, and slabs. The article describes refractory selection criteria and the methods of mounting and securing the induction coil winding, and presents general refractory installation guidelines for induction heating applications. It provides information on curing, form removal, dryout, and coil refractory seasoning. Wear rails that are designed to prevent damage to the coil refractory and subsequent coil winding are also discussed. The article concludes with a discussion on preventive maintenance practices for induction forging coils.