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 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.

Forming processes can be divided into three major categories: bulk forming, sheet-metal forming, and semisolid forming and polymer extrusion. This article introduces each process category with a description of the constitutive models. It outlines the required properties for process modeling and describes the test methods for determining these properties. The article discusses several compression tests used to determine stress-strain curves for bulk forming and tensile tests used to obtain stress-strain curves for sheet-metal forming. The article concludes with information on the measurement of viscosity of semisolid alloy materials by using three types of viscometers: the coaxial cylinder viscometer, the cone-and-plate viscometer, and the capillary viscometer.

This article discusses the equipment design, procedures, experimental considerations, and interpretation of the torsion tests used to establish workability. It describes the application of torsion testing to obtain flow-stress data and to gage fracture-controlled workability and flow-localization-controlled failure. The article discusses the torsion test used to establish the processing parameters that are required to produce the desired microstructures.

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 emphasizes short-term tension and compression testing of metals at high temperatures. It describes the effect of temperature on deformation and strain hardening, occurrence of high-temperature creep in structural alloys, and the performing of mechanical testing for high-temperature structural alloys. The article discusses hot tension testing and measurements of temperature and strain in the hot tension testing. It also provides an overview of hot compression testing.

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.

The thermomechanical processing (TMP) of conventional and advanced nickel and titanium-base alloys is aimed at altering or enhancing one or more metallurgical features within the material and component. This article presents a number of examples of the TMP of nickel-base superalloys and titanium alloys. The TMP techniques include retained-strain processing, dual-microstructure processing, and dual-alloy processing. The article also describes the TMP of alpha-beta titanium alloys, including fine-grain processing, hybrid-structure processing, dual-microstructure processing, and dual-alloy processing. It concludes with a discussion on computer simulation of advanced TMP processes.

This article provides a summary of the overall development of the finite element method (FEM) and its contribution to the materials forming industry. It focuses on the overall philosophy and evolution of the FEM for solving bulk forming issues. A number of applications of FEM are presented in the order they would be used in a typical manufacturing process sequence: primary materials processing, hot forging and cold forming, and product assembly. The article discusses four FEM modules: the deformation model, the heat-transfer model, the microstructural model, and the carbon diffusion model. The article also covers material fracture and die stress analysis and reviews optimization of the design of forming processes.

This article discusses two types of hot-tension tests, namely, the Gleeble test and conventional isothermal hot-tension test, as well as their equipment. It summarizes the data for hot ductility, strength, and hot-tension for commercial alloys. The article presents isothermal hot-tension test data, which helps to gain information on a number of material parameters and material coefficients. It details the effect of test conditions on flow behavior. The article briefly describes the detailed interpretation of data from the isothermal hot-tension test using numerical model. It also explains the cavitation mechanism and failure modes that occur during hot-tension testing.

This article provides a summary of the overall development of the finite element method (FEM) and its contribution to the materials forming industry. It presents an overview of FEM methodologies and applications in the order of their usage in typical manufacturing (bulk forming process) process sequence: primary materials processing, hot forging and cold forming, and product assembly. The article discusses the material fracture and dies stress analysis and presents the optimization techniques used in 2-D and 3-D preform die design.

The primary purpose of this article is to describe general root causes of failure that are associated with wrought metals and metalworking. This includes a brief review of the discontinuities or imperfections that may be common sources of failure-inducing defects in the bulk working of wrought products. The article addresses the types of flaws or defects that can be introduced during the steel forging process itself, including defects originating in the ingot-casting process. Defects found in nonferrous forgings—titanium, aluminum, and copper and copper alloys—also are covered.