This article presents six case studies of failures with steel forgings. The case studies covered are crankshaft underfill; tube bending; spade bit; trim tear; upset forging; and avoidance of flow through, lap, and crack. The case studies illustrate difficulties encountered in either cold forging or hot forging in terms of preforge factors and/or discontinuities generated by the forging process. Supporting topics that are discussed in the case studies include validity checks for buster and blocker design, lubrication and wear, mechanical surface phenomenon, forging process design, and forging tolerances. Wear, plastic deformation processes, and laws of friction are introduced as a group of subjects that have been considered in the case studies.

In forgings of both ferrous and nonferrous metals, the flaws that most often occur are caused by conditions that exist in the ingot, by subsequent hot working of the ingot or the billet, and by hot or cold working during forging. The inspection methods most commonly used to detect these flaws include visual, magnetic particle, liquid penetrant, ultrasonic, eddy current, and radiographic inspection. This chapter provides a detailed discussion on the characteristics, process steps, applications, advantages, and limitations of these methods. It also describes the flaws caused by the forging operation and the principal factors that influence the selection of a nondestructive inspection method for forgings.

This appendix includes contact information for titanium manufacturers, suppliers, and service providers.

This chapter discusses the factors involved in the design of impression-die forging systems. It begins by presenting a flow chart illustrating the basic steps in the forging design process and a block diagram that shows how key forging variables are related. It then describes the requirements of various forging alloys, the influence of machine operating parameters, and production challenges related to lot tolerances and shape complexity. The chapter also covers the design of finisher dies, the prediction of forging stresses and loads, and the design of preform dies for steel, aluminum, and titanium alloys.

Casting is one of the basic processes used for the shaping of steel. It is economical in both cost and time of production. Numerous components are produced from cast steel because of the advantages of the process. These advantages can best be described under the following headings: design flexibility, metallurgical versatility and quality, and economic benefits. This chapter looks at these advantages of steel castings. Of major interest is the comparison of cast steel with wrought steel and weldments in terms of properties, availability, cost, and quality. The chapter also includes information on cast steel compared to other cast metals and other methods of steel fabrication.

This chapter discusses bulk deformation processes and how they are used to reshape metals and refine solidification structures. It begins by describing the differences between hot and cold working along with their respective advantages. It then discusses various forging methods, including open-die and closed-die forging, hot upset and roll forging, high-energy-rate forging, ring rolling, rotary swaging, radial and orbital forging, isothermal and hot-die forging, precision forging, and cold forging. The chapter also includes information on cold and hot extrusion and drawing operations.

This chapter explains how to recognize decarburization and related defects. It includes images showing how decarburization appears in various steels, discusses stock removal practices, and describes common defects and flaws such as quench cracks and where they are typically found.