When a metal is alloyed with another metal, either substitutional or interstitial solid solutions are usually formed. This chapter discusses the general characteristics of these solutions and the effects of several alloying elements on the yield strength of pure metals. It presents four rules that give a qualitative estimate of the ability of two metals to form substitutional solid solutions: relative size factor, chemical affinity factor, relative valency factor, and lattice type factor. The chapter provides information on alloys that form an ordered structure during heating. It describes the intermediate phases that are formed during solidification between the two extremes of substitutional solid solution on the one hand and intermetallic compound on the other. The chapter concludes with a section on strain aging in low-carbon steels that allows the interstitial atoms to diffuse to the dislocations and again form atmospheres that pin dislocation movement.

This chapter addresses the cumulative effects of fatigue and how to determine its impact on component lifetime and performance. It begins by defining a loading history and its corresponding hysteresis loops that exposes the deficiencies of some of the theories discussed. It then proceeds to demonstrate the methods commonly used to analyze cumulative fatigue damage and its effect on component life starting with the classical linear damage rule. After pointing out the inherent limitations of the model, it presents a method that incorporates two linear damage rules, one applying prior to crack initiation and the other after the crack has started. Although the method accounts somewhat better for loading-order effects, the transition in behavior that the rules presume to model occurs prior to any signs of cracking. Two modified versions of the double linear damage rule method, neither of which are related to a physical crack initiation event, are subsequently presented along with several applications showing how the different methods compare. The examples provided include two-level and multilevel tests, a gas-turbine engine compressor disk, and the cumulative damage associated with the irreversible hardening of type 304 stainless steel.

This chapter addresses the issue of retained austenite in quenched carburized steels. It explains why retained austenite can be expected at the surface of case-hardened components, how to estimate the amount that will be present, and how to effectively stabilize or otherwise control it. It presents detailed images and data plots showing how retained austenite appears and how it influences hardness, tensile properties, residual stresses, fatigue and fracture behaviors, and wear resistance.

This chapter discusses the composition and structure of low-carbon irons and steels, particularly those used in the production of hot-rolled strip. It describes the manufacturing process from the production of ingots to coiling, and it explains how finishing and coiling temperatures affect ferritic grain size and the distribution of cementite particles. It also discusses subsequent processing, including cold rolling and annealing, and the parameters with the greatest impact on grain size and microstructure. In addition, it describes the production of enameling irons, the benefits of high-temperature heat treatments, and the effects of quench and strain aging.