This chapter discusses the fundamentals of plastic deformation and the role of strain and strain rate in sheet metal forming processes. It describes the conditions associated with uniform deformation, the significance of engineering and true strain, the effect of volume constancy on the tensile response of isotropic and anisotropic materials, and how infinitesimal strains or strain rates are used to express and analyze instantaneous deformation and local stain. It also discusses the concept of principal strain and strain paths and explains how to determine, and when to use, equivalent strain and strain rate.

The design and optimization of sheet metal forming operations is aided by tools and techniques that have been developed and refined over several decades. This chapter covers many of these methods and practices and explains where and how they are used. It begins by showing how the stress state at any point in a material can be expressed in different ways for different purposes. It then compares and contrasts some of the more widely used yield criteria and demonstrates the use of flow rules. It also explains how to calculate power, energy, and effective strain and strain rate and how hardening laws are used to predict strain-hardening behaviors.

The stress-strain curves in this data set are representative examples of the behavior of several cast alloys under tensile or compressive loads. The curves are arranged by alloy designation. Each figure cites the original source of the curve and provides pertinent background information as available. Compressive tangent modulus curves are presented for certain alloys. The effects of cyclic loading are given on several curves.

Mechanical components often require surface treatments to meet application demands. This chapter describes several surface hardening treatments for steel and their effect on microstructure, composition, and properties. It discusses flame hardening, induction heating, carburizing, nitriding, carbonitriding, and nitrocarburizing. The discussion on carburizing addresses several interrelated factors, including processing principles, alloying, surface oxidation, residual stresses, bending fatigue, contact fatigue, and fracture.

This chapter discusses the basic principles of precipitation hardening, an important strengthening mechanism in nonferrous alloys as well as stainless steel. It begins with a detailed review of the theory of precipitation hardening, then describes its application to aluminum alloys and nickel-base superalloys.

Precipitation hardening is used extensively to strengthen aluminum alloys, magnesium alloys, nickel-base superalloys, beryllium-copper alloys, and precipitation-hardening stainless steels. This chapter discusses two types of particle strengthening: precipitation hardening, which takes place during heat treatment; and true dispersion hardening, which can be achieved by mechanical alloying and powder metallurgy consolidation. It provides information on the three steps of precipitation hardening of aluminum alloys: solution heat treating, rapid quenching, and aging.

This chapter discusses the stress-strain response of ferritic microstructures and its influence on tensile deformation, strain hardening, and ductile fracture of carbon steels. It describes the ductile-to-brittle transition that occurs in bcc ferrite, the effects of aging and grain size on strength and toughness, continuous and discontinuous yielding behaviors, and dispersion and solid-solution strengthening processes.

This chapter examines the stress-strain characteristics of metals and alloys subjected to cyclic loading and the cumulative effects of fatigue. It begins by explaining how a single load reversal can lower the yield stress of a material and how repeated reversals can cause strain hardening and softening, both of which lead to premature failure. It then discusses the stages of fatigue fracture, using detailed images to show how cracks initiate and grow and how they leave telltale marks on fracture surfaces. It goes on to describe fatigue life assessment methods and demonstrate their use on different metals and alloys. The chapter also discusses design-based approaches for preventing fatigue failures.

This chapter provides a detailed analysis of the deep drawing process. It begins by explaining that different areas of the workpiece are subjected to different types of forces and loads, equating to five deformation zones. After describing the various zones, it discusses the effect of key process parameters including the draw ratio, material properties, geometry, interface conditions, equipment operating speed, and tooling. It then walks through the steps involved in predicting stress, strain, and punch force using the slab method and finite element analysis and presents the results of simulations conducted to assess the influence of blank diameter, thickness, and holding force as well as strain-hardening and strength coefficients. It also discusses the cause of defects in deep drawn rectangular cups and presents the case study of a deep drawn rectangular cup made from an aluminum blank.

This appendix provides readers with worked solutions to 25 problems involving calculations associated with tensile testing and the determination of mechanical properties and variables. The problems deal with engineering factors and considerations such as stress and strain, loading force, sample lengthening, and machine stiffness, and with mechanical properties and parameters such as elastic modulus, Young’s modulus, strength coefficient, strain-hardening exponent, and modulus of resilience. They also cover a wide range of materials including various grades of aluminum and steel as well as iron, titanium, brass, and copper alloys.

During fusion welding, the thermal cycles produced by the moving heat source causes physical state changes, metallurgical phase transformations, and transient thermal stresses and metal movement. This chapter begins by discussing weld metal solidification behavior and the solid-state transformations of the main classes of metals and alloys during fusion welding. The main classes include work- or strain-hardened metals and alloys, precipitation-hardened alloys, transformation-hardened steels and cast irons, stainless steels, and solid-solution and dispersion-hardened alloys. The following section provides information on the residual stresses and distortion that remain after welding. The focus then shifts to distortion control of weldments. Inclusions and cracking are discussed in detail. The chapter also discusses the causes for reduced fatigue strength of a component by a weld: stress concentration due to weld shape and joint geometry; stress concentration due to weld imperfections; and residual welding stresses. Inspection and characterization of welds are described in the final section of this chapter.

This chapter summarizes the performance attributes of advanced high-strength steels, namely stiffness, strength, strain hardening, fatigue, crashworthiness, formability, toughness, and bake hardening.

This appendix provides information on temper designations for strain-hardened aluminum, heat treatable aluminum alloys, and annealed aluminum products.

The various types of stainless steel have very different deformation characteristics in terms of strain hardening and anisotropy. It is important to understand and exploit these characteristics to optimize forming of stainless steels. This chapter discusses the various deformation processes involved in sheet-forming techniques, namely stretch forming and deep drawing. In addition, it provides information on some of the factors pertinent to cold-heading and hot forming of stainless long products.

This chapter discusses the composition, alloying characteristics, mechanical properties, corrosion resistance, advantages, limitations, and applications of martensitic, semiaustenitic, and austenitic precipitation-hardenable stainless steels.

Titanium, like other metals, can be shaped, formed, and strengthened through deformation processes. This chapter describes the structural changes that occur in titanium during deformation and how they can be controlled. It discusses the role of slip, dislocations, and twinning, the effect of grain size and crystal orientation, the concept of texture strengthening, and the principles of strain hardening and superplasticity. It also discusses the effect of annealing and the difference between recrystallization and neocrystallization processes.

Induction heating, in most applications, is used to selectively heat only a portion of the workpiece that requires treatment. This chapter covers the basic principles, features, and metallurgical aspects of induction heating. The discussion includes the conditions required for induction heating and quenching, the use of magnetic flux concentrators to improve the efficiency of surface heating, and the quenching systems used for induction hardening. The discussion also provides information on time-temperature dependence in induction heating, workpiece distortion in induction surface hardening, residual stresses after induction surface hardening and finish grinding, and input and output control of steel for induction surface hardening of gears.

This chapter discusses the processes involved in the heat treatment of steel, namely austenitizing, hardening, quenching, and tempering. It begins with an overview of austenitizing of steels by induction heating, followed by a discussion on the processes involved in transformation of the soft austenite into martensite or lower bainite in the hardening operation. The chapter provides information on various quenching systems and a description of quenching techniques, namely austempering, martempering, and patenting. Difficulties associated with hardening of steel are discussed. Further, the chapter describes the equipment used for and principal variables of tempering. It discusses the causes for various forms of embrittlement due to tempering. Information on multiple tempering, protective-atmosphere tempering, and selective tempering are also provided, along with processes involved in selection of tempering temperature. The chapter ends with a section discussing various effects, advantages, and disadvantages of precipitation hardening.

This chapter discusses the stress-strain response of materials, how it is measured, and how it used to set performance expectations. It begins by describing the common tensile test and how it sheds light on the elastic design of structures as well as plasticity and fracture behaviors. It explains how engineering and true stress-strain curves differ, how one is used for design and the other for analyzing metal forming operations. It discusses the effect of holes, fillets, and radii on the distribution of stresses and the use of notch tensile testing to detect metallurgical embrittlement. The chapter also covers compression, shear, and torsion testing, the prediction of yielding, residual stress, and hardness.

This chapter discusses the forming characteristics of dual-phase (DP) and transformation-induced plasticity (TRIP) steels. It begins with a review of the mechanical behavior of advanced high-strength steels (AHSS) and how they respond to stress-strain conditions associated with deformation processes such as stretching, bending, flanging, deep drawing, and blanking. It then describes the complex tribology of AHSS forming operations, the role of lubrication, the effect of tool steels and coatings, and the force and energy requirements of various forming presses. It also discusses the cause of springback and explains how to predict and compensating for its effects.