An important activity in metalworking facilities is the testing of raw materials for characteristics that ensure the integrity and quality of the products made. This article reviews the common material parameters that can have a direct or indirect influence on workability and product quality. These include strength, ductility, hardness, strain-hardening exponent, strain-rate effects, temperature effects, and hydrostatic pressure effects. The article also reviews the material behavior characteristics typically determined by mechanical testing methods. It discusses various mechanical testing methods, including the tension test, plane-strain tension test, compression test, plane-strain compression test, partial-width indentation test, and torsion test. Aspects of testing particularly relevant to workability and quality control for metalworking processes are also described. Finally, the article details the various factors influencing workability in bulk deformation processes and formability in sheet-metal forming.

Sheet metal forming operations are so diverse in type, extent, and rate that no single test provides an accurate indication of the formability of a material in all situations. This article presents an overview of types of forming, formability problems, and principal methods of measuring deformation. It reviews the effect of materials properties and temperature on formability. The article provides a detailed discussion on the two major categories of formability tests such as the intrinsic test, including uniaxial tension testing, plane-strain tension testing, biaxial stretch testing, and simulative tests such as bending tests, stretching tests, the Ohio State University test, the drawing test, and stretch-drawing tests. It extends the correlation between simulative tests and materials properties using forming limit diagrams and circle grid analysis, and discusses the improvements to the forming limit diagram technology.

This article focuses on the factors that determine the extent of deformation a metal can withstand before cracking or fracture occurs. It informs that workability depends on the local conditions of stress, strain, strain rate, and temperature in combination with material factors. The article discusses the common testing techniques and process variables for workability prediction. It illustrates the simple and most widely used fracture criterion proposed by Cockcroft and Latham and provides a workability analysis using the fracture limit line. The article describes various workability tests, such as the tension test, ring compression test, plane-strain compression test, bend test, indentation test, and forgeability test. It concludes with information on the role of the finite-element modeling software used in workability analysis.

This article discusses a number of workability tests that are especially applicable to the forging process. The primary tests for workability are those for which the stress state is well known and controlled. The article provides information on the tension test, torsion test, compression test, and bend test. It examines specialized tests including plane-strain compression test, partial-width indentation test, secondary-tension test, and ring compression test. The article explains that workability is determined by two main factors: the ability to deform without fracture and the stress state and friction conditions present in the bulk deformation process. These two factors are described and brought together in an experimental workability analysis.

This article describes the most commonly used test methods for determining flow stress in metal-forming processes. The methods include tension, ring, uniform compression, plane-strain compression, torsion, split-Hopkinson bar, and indentation tests. The article discusses the effect of deformation heating on flow stress. It provides metallurgical considerations at hot working temperatures and presents flow curves at conventional metalworking strain rates. The article describes the effect of microstructural scale, crystallographic texture, and equiaxed phases on flow stress at hot working temperatures. It tabulates a summary of certain values describing the flow stress-strain rate relation for steels, aluminum alloys, copper alloys, titanium alloys, and other metals at various temperatures.

This article presents formulas for calculating the following: effective stress, strain, and strain rate (isotropic material) in arbitrary coordinates and in principal coordinates; compression testing, tension testing, and torsion testing of isotropic material; and Barlat's anisotropic yield function Yld2000-2d for plane-stress deformation of sheet material. It also contains formulas related to flat (sheet) rolling, conical-die extrusion, wire drawing, bending, and deep drawing of cups from sheet metal.

This article provides the general mechanical testing guidelines for the characterization of lamina and laminate properties. Guidelines are provided for tensile property, compressive property, shear property, flexure property, fracture toughness, and fatigue property test methods. The article also tabulates selected standards for lamina and laminate mechanical testing.

This article describes the use of compression tests, namely, cylindrical compression, ring compression, and plane-strain compression tests at elevated temperatures. It discusses the effects of the temperature, strain rate, and deformation heating on metals during the cylindrical compression test, with the help of flow curves. The article illustrates the testing apparatus used in the cylindrical compression test. It describes the issues regarding friction and temperature, and strain-rate control with proper test equipment and experimental planning during the ring compression test and plane-strain compression test. The article also reviews the testing conditions, procedures, and advantages of hot plane-strain compression test.

This article contains nine tables that present useful formulas for deformation analysis and workability testing. The tables present formulas for effective stress, strain, and strain rate in arbitrary coordinates, principal, compression and tension testing of isotropic material. The article also provides formulas for flat rolling, conical-die extrusion, wire drawing, deep drawing of cups from sheet metal, and bending, and formulas for anisotropic sheet materials.

This article begins with a review of the purposes of mechanical characterization tests and the general considerations related to the mechanical properties of anisotropic systems, specimen fabrication, equipment and fixturing, environmental conditioning, and analysis of test results. It provides information on the specimen preparation, instrumentation, and procedures for various mechanical test methods of fiber-reinforced composites. These include the compression test, flexure test, shear test, open hole tension test, and compression after impact test. The article describes three distinct fracture modes, namely, crack opening mode, shearing mode, and tearing mode. It presents an overview of fatigue testing and fatigue damage mechanisms of composite materials and reviews the types of mechanical measurements that can be made during the course of testing to assess fatigue damage. The article concludes with a discussion on the split-Hopkinson pressure bar test.

This article presents a comprehendable and comprehensive physics-based approach for characterizing the strength of fiber-reinforced polymer composites. It begins with background information on the goals and attributes of this method. The article then addresses the characterization of fiber failures in laminates, because these are at the highest strengths that can be attained and, therefore, are usually the design objective. An exception would be if the design goal is to maximize energy absorption, rather than static strength. The discussion proceeds to situations in which the matrix fails first, either by intent, by design error, or because of impact damage. The state of the modeling propagation and arrest of matrix damage follows. Comparisons of this physics-based approach are then made to empirically based failure theories.

This article is a comprehensive collection of tables containing formulas for metals processing, namely, casting and solidification, flat (sheet) rolling, conical-die extrusion, wire drawing, bending, and deep drawing. Formulas for compression, tension, and torsion testing of isotropic materials are included. The article also lists the formulas for effective stress, strain, and strain rate (isotropic material) in arbitrary and principal coordinates; dimensionless groups in fluid mechanics; and anisotropic sheet materials at various loading conditions.

This article explores why structural element and subcomponent testing are conducted. It discusses the different types of failure modes in composites, and provides information on the testing methodology, fixturing, instrumentation, and data reporting. The article reviews various standard elements used to characterize composite materials for the various failure modes. Simple structural-element testing under in-plane unidirectional, multidirectional, and combined loading, as well as out-of-plane loading are discussed. Simple bolted and bonded joints, as well as data correlation are reviewed with analytical predictions. The article also provides a list of the ASTM testing standards applicable at the element level of testing for both polymer-matrix composites and metal-matrix composites. It concludes with a discussion on durability and damage tolerance testing.

This article provides the definitions of stress and strain, and describes the relationship between stress and strain by stress-strain curves and true-stress/true-strain curves. The emphasis is on understanding the factors that determine the extent of deformation a metal can withstand before cracking or fracture occurs. The article reviews the process variables that influence the degree of workability and summarizes the mathematical relationships that describe the occurrence of room-temperature ductile fracture under workability conditions. It discusses the most common situations encountered in multiaxial stress states. The construction of a processing map based on deformation mechanisms is also discussed.

This article reviews the common methods of shear and multiaxial testing for the evaluation of engineering components such as fasteners and mill products. It discusses shear test methods, including through-thickness tests, in-plane shear tests, and double-notched shear test. The article provides information on torsional (rotational shear) tests as well as the basic equipment and setup of torsion testing. Motors, twist and torque transducers, torque sensors, and heating systems as well as the specimen preparation procedure are also discussed.

Springback refers to the elastically driven change of shape that occurs after deforming a body and then releasing it. This article presents an introduction to the concepts of springback simulation as well as recommendations for its practice in a metal forming setting of thin beams or sheets. It discusses bending with tension and more complex numerical treatments. The article addresses the limitations of the various assumptions followed in springback simulation. It provides a discussion on the design of dies and tooling using an assumed springback prediction capability.

An integral aspect of designing and material selection is the use of mechanical properties derived from various mechanical testing. This article introduces the basic concepts of mechanical design and its relation with the properties derived from various mechanical testings, namely, tensile, compressive, hardness, torsion and bend, shear load, shock, and fatigue and creep testings. It describes the design criteria for combined properties derived from each of the mechanical testing. The article concludes with a discussion on the effect of environment on the mechanical properties.