This chapter discusses the factors influencing the corrosion resistance of bulk materials, namely alloying, metallurgical factors, and mechanical treatments.

Stainless steels and nickel-base alloys are recognized for their resistance to general corrosion and other categories of corrosion. This chapter examines the effects of specific alloying elements, metallurgical structure, and mechanical conditioning on the corrosion resistance of these alloys. Some categories of corrosion covered are pitting, crevice, intergranular, stress-corrosion cracking, general, and high-temperature corrosion.

The basic concept for most methods of corrosion protection is to remove one or more of the electrochemical cell components so that the pure metal or metal alloy of interest will not corrode. Another widely used corrosion protection approach is to change the nature of the anode so that it becomes the cathode (cathodic protection). This chapter briefly reviews these methods of corrosion protection. The factors affecting corrosion behavior are covered. In addition, the chapter provides information on coatings and inhibitors, which are used in corrosion protection.

This chapter is a compilation of terms and definitions related to heat treating.

This chapter provides a brief but practical overview of the case carburizing process. It discusses the benefits and challenges of the process and compares and contrasts it with other hardening methods. It explains how design allowables and safety factors compensate for unknowns and familiarizes readers with the steps involved in determining case depth and verifying that case carbon requirements have been met.

Engineered geometry and its microstructures impact casting performance. This chapter describes three interdependent disciplines that are needed to achieve product performance and cost targets, namely engineered geometry; target microstructure and chemistry; and optimum process for high integrity.

A systematic procedure for minimizing risks involved in heat treated steel components requires a combination of metallurgical failure analysis and fitness for service with respect to safety and reliability based on risk analysis. This chapter begins with an overview of heat treat processing of steels. This is followed by sections on various aspects of heat treatment design and heat treating practices for minimizing distortion. Influence of design, steel grade, and condition is then illustrated in the examples of failures due to heat treatment. A procedure is analyzed to improve the performance of the design process of a component. A heat-transfer model, coupling with a phase transformation model, a thermomechanical model, and a thermochemical model, is also considered. The chapter further provides information on the failure aspects of and heat treatment procedures applied to welded components. It ends with a section on risk-based approach applicable to heat treated steel components.

This chapter discusses the various factors influencing the evaluation of fatigue fracture of nitrided layers. It begins by describing the problems of enhancing the fatigue resistance of machine components. The significance and detailed assessment of the effect of a structural flaw are then explained, using investigations of the effect of variable core conditions on fatigue resistance as an example. This is followed by a discussion on the processes involved in the evaluation of fatigue properties of nitrided steels. The chapter also describes the determination of the fatigue characteristics of nitrided steels after the carbonitriding treatment.

Gaseous ferritic nitrocarburizing, like salt bath nitrocarburizing, involves the introduction of carbon and nitrogen into steel in order to produce a thin layer of iron carbonitride and nitrides, the "white layer" or compound layer, with an underlying diffusion zone containing dissolved nitrogen and iron (or alloy) nitrides. This chapter first presents the development and principles of the process. It then discusses the properties of gaseous ferritic nitrocarburized components. The chapter also presents the applications for the ferritic nitrocarburizing process. It provides an overview of the safety considerations.

The metallurgy of aluminum and its alloys offers a range of opportunities for employing heat treatments to obtain desirable combinations of mechanical and physical properties such that castings meet defined temper requirements. This chapter discusses the processes involved in solution heat treatment, quenching, precipitation hardening, and annealing of aluminum alloys. The effects of these processes on dimensional stability and residual stresses are also discussed. Troubleshooting and diagnosis of heat treating problems are covered in the concluding section of the chapter.

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.

Steel is an important material because of its tremendous flexibility in metal working and heat treating to produce a variety of mechanical, physical, and chemical properties. The purpose of this chapter is to present the metallurgical principles of heat treatment of steel in a generalized manner. The chapter provides a discussion on the constitution of commercially pure iron, subsequently leading to discussion on the iron-carbon alloy system. The chapter also describes the effect of carbon on the constitution of iron and of the solubility of carbon in iron. It provides information on transformations and on the classification of steels by carbon content. The chapter ends with a discussion on the effect of time on transformation and on the use of time-temperature-transformation diagrams.

This chapter discusses the compositions, metallurgical phases, microstructure, heat treatment, grades, and structure-property relationships of steels. In addition, it describes the mechanisms involved in deformation, strengthening, and annealing of steels.

This chapter discusses the metallurgical considerations and process requirements of nitriding. It presents the pioneering work of Adolph Machlet and Adolph Fry and presents early developments. One such development is the Floe process, a two-stage treatment used to reduce the formation of a compound layer on the surface of a nitrided steel.

Several process parameters must be considered to ensure success in achieving desired metallurgical properties and to minimize distortion. This chapter provides a detailed discussion on the liberation of nitrogen, dissociation of the gas at the selected nitriding temperature, why ammonia is used, distortion, and preheat treatment.

This chapter presents basic principles and the theoretical results of heat transport in solids. Thermal conductivity and thermal diffusivity are the principal properties discussed. Discussions are also included on the effects of temperature, magnetic field, and metallurgical variations caused by composition, processing, and heat-treatment differences. Numerous graphs illustrate the qualitative and quantitative effects of these variables. Measurement methods and associated accuracies and pertinent empirical correlations are presented.

Induction heating has found widespread use as a method to raise the temperature of a metal prior to forming or joining, or to change its metallurgical structure. However, induction heating has specialized capabilities that make it suitable for applications outside of metal treatment and fabrication. This chapter summarizes some of the special applications of induction heating, including those in the plastics, packaging, electronics, glass, chemical, and metal-finishing industries. The chapter concludes with a discussion of the application of induction heating for vacuum processes.

This appendix provides supplemental information on the metallurgical aspects of atomic structure, the use of dislocation theory, heat treatment processes and procedures, important engineering materials and strengthening mechanisms, and the nature of elastic, plastic, and creep strain components. It also provides information on mechanical property and fatigue testing, the use of hysteresis energy to analyze fatigue, a procedure for inverting equations to solve for dependent variables, and a method for dealing with the statistical nature of failure.

Carbon and low-alloy steels are the most frequently welded metallic materials, and much of the welding metallurgy research has focused on this class of materials. Key metallurgical factors of interest include an understanding of the solidification of welds, microstructure of the weld and heat-affected zone (HAZ), solid-state phase transformations during welding, control of toughness in the HAZ, the effects of preheating and postweld heat treatment, and weld discontinuities. This chapter provides information on the classification of steels and the welding characteristics of each class. It describes the issues related to corrosion of carbon steel weldments and remedial measures that have proven successful in specific cases. The major forms of environmentally assisted cracking affecting weldment corrosion are covered. The chapter concludes with a discussion of the effects of welding practice on weldment corrosion.

Nickel-base castings are produced from a group of alloys with compositions that are typically greater than 50% Ni and less than 10% iron. This chapter presents the casting compositions of nickel-base alloys. It then provides an overview of heat treatment, mechanical properties, and applications of nickel-base castings.