This article discusses the effects of alloying on the properties and behaviors of maraging steels. It describes how maraging steels differ from conventional steels in that they are strengthened, not by carbon, but by the precipitation of intermetallic compounds. It explains how maraging steels typically have high levels of nickel, cobalt, and molybdenum with little carbon content and how that affects their dimensional stability, fracture toughness, weldability, and resistance to stress-corrosion cracking.

High-strength steels are susceptible to stress-corrosion cracking (SCC) even in moist air. This chapter identifies such steels and the applications where they are typically found. It provides information on crack growth kinetics and crack propagation models in which hydrogen embrittlement is the predominant mechanism. It explains how different application variables affect SCC, including loading mode, state of stress, type of steel, temperature, electrochemical potential, heat treatment, and deformation processes. It also compares SCC characteristics in different high-strength steels and discusses the influence of composition, steelmaking practice, and application environment.

Alloy steels are alloys of iron with the addition of carbon and one or more of the following elements: manganese, chromium, nickel, molybdenum, niobium, titanium, tungsten, cobalt, copper, vanadium, silicon, aluminum, and boron. Alloy steels exhibit superior mechanical properties compared to plain carbonsteels as a result of alloying additions. This chapter describes the beneficial effects of these alloying elements in steels. It discusses the mechanical properties, nominal compositions, advantages, and engineering applications of various classes of alloy steels. They are low-alloy structural steels, SAE/AISI alloy steels, high-fracture-toughness steels, maraging steels, austenitic manganese steels, high-strength low-alloy steels, dual-phase steels, and transformation-induced plasticity steels.

This appendix provides tensile property and fracture toughness data for various low-alloy and stainless steels.

The possible classification for tool steels is their division into four groups according to their final application: hot-worked, cold-worked, plastic mold, and high-speed tool steels. This chapter mainly follows such division by application, but the grade nomenclatures used here are primarily from AISI. It presents the classification of tool steels and discusses the principles and processes of tool steel heat treating, namely normalizing, annealing, hardening, and tempering. Various factors associated with distortion in several tool steels are also covered. The chapter discusses the composition, classification, and properties of unalloyed and low-alloy cold-worked tool steels; medium and high-alloy cold-worked tool steels; and 18% nickel maraging steels.

This article discusses the compositions, structures, and properties of the most common grades of soft magnetic metals and permanent magnet alloys. It explains how alloying additions and impurities affect the magnetic properties of these materials, which include commercially pure and phosphorus irons, low-carbon and silicon steels, ferritic stainless steels, and nickel-iron and iron-cobalt alloys.

This chapter familiarizes readers with the methods used to quantify the effects of fatigue on component lifetime and failure. It discusses the development and use of S-N (stress amplitude vs. cycles to failure) curves, the emergence of strain-based approaches to fatigue analysis, and important refinements and modifications. It demonstrates the use of approximate equations, including the method of universal slopes and the four-point correlation technique, which provides reasonable estimates of elastic and plastic lines from information obtained in standard tensile tests. It also discusses high-cycle, low-cycle, and ultra-high cycle fatigue and presents several models that are useful for fatigue life predictions.

Sulfur is one of the most common corrosive contaminants in high-temperature industrial environments and its presence can cause a number of problems, including sulfidation. This chapter describes the sulfidation behavior of a wide range of alloys as observed in three types of industrial environments. One environment consists of sulfur vapor, hydrocarbon streams, H2S, and H2-H2S gas; sulfides are the only corrosion products that form under these conditions. Another environment consists of H2, CO, CO2, H2S, and other gases, causing the formation of oxides as well as sulfides in most alloys. The third environment, for which less data exists, contains either SO2 or O2-SO2 mixtures.

This article discusses the composition, properties, and behaviors of copper and its alloys. It begins with an overview of the characteristics, applications, and commercial grades of wrought and cast copper. It then discusses the role of alloying, explaining how zinc, tin, aluminum, silicon, and nickel affect the physical and mechanical properties of coppers and high-copper alloys as well as brasses, bronzes, copper-nickels, and nickel silvers. It also explains how alloying affects electrical conductivity, corrosion resistance, stress-corrosion cracking, and processing characteristics.

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.

Strain-range partitioning is a method for assessing the effects of creep fatigue based on inelastic strain paths or strain reversals. The first part of the chapter defines four distinct strain paths that can be used to model any cyclic loading pattern and describes the microstructural damages associated with each of the four basic loading cycles. The discussion then turns to fatigue life prediction for different types of materials and more realistic loading conditions, particularly those in which hysteresis loops have more than one strain-range component. To that end, the chapter considers two cases. In one, the relationship between strain range and cyclic life is established from test data. In the other, a rule is required to determine the damage of each concurrent strain and the total damage of the cycle is used to predict creep-fatigue life. The chapter presents several such damage rules and discusses their applicability in different situations.

This chapter discusses various types of material fracture toughness and the methods by which they are determined. It begins with a review of the basic principles of linear elastic fracture mechanics, covering the Griffith-Irwin theory of fracture, the concept of strain energy release rate, the use of fracture indices and failure criteria, and the ramifications of crack-tip plasticity in ductile and brittle fractures. It goes on to describe the different types of plain-strain and plane-stress fracture toughness, explaining how they are measured and how they are influenced by metallurgical and environmental variables and loading conditions. It also examines the crack growth resistance curves of several aluminum alloys and describes the characteristics of fracture when all or some of the applied load is in the plane of the crack.

This chapter presents an overview of families of brazing alloys that one is likely to encounter in a manufacturing environment. It discusses the metallurgical aspects of brazing and includes a survey of brazing alloy systems. A discussion of deleterious and beneficial impurities is provided with examples. The chapter also describes the application of phase diagrams to brazing.

All materials are susceptible to corrosion or some form of environmental degradation. Although no single material is suitable for all applications, usually there are a variety of materials that will perform satisfactorily in a given environment. The intent of this chapter is to review the corrosion behavior of the major classes of metals and alloys as well as some nonmetallic materials, describe typical corrosion applications, and present some unique weaknesses of various types of materials. It also aims to point out some unique material characteristics that may be important in material selection, and discuss, where appropriate, the characteristic forms of corrosion that attack specific materials. The materials addressed in this chapter include carbon steels, weathering steels, and alloy steels; nickel, copper, aluminum, titanium, lead, magnesium, tin, zirconium, tantalum, niobium, and cobalt and their alloys; polymers; and other nonmetallic materials, including rubber, carbon and graphite, and woods.

This chapter discusses material-related problems associated with coal-fired burners. It explains how high temperatures affect heat-absorbing surfaces in furnace combustion areas and in the convection pass of superheaters and reheaters. It describes how low-NOx combustion technology, intended to reduce NOx emissions, accelerates tube wall wastage. It also covers circumferential cracking in furnace waterwalls, thermal fatigue cracking induced by waterlances and water cannons, superheater-reheater corrosion, and erosion in fluidized-bed boilers.

This chapter addresses the challenge of selecting an appropriate stress-corrosion cracking (SCC) test to evaluate the serviceability of a material for a given application. It begins by establishing a generic model in which SCC is depicted in two stages, initiation and propagation, that further subdivide into several zones plus a transition region. It then discusses SCC test standards before describing basic test objectives and selection criteria. The chapter explains how to achieve the required loading conditions for different tests and how to prepare test specimens to determine elastic strain, plastic strain, and residual stress responses. It also describes the difference between smooth and precracked specimens and how they are used, provides information on slow-strain-rate testing and how to assess the results, and discusses various test environments and procedures, including tests for weldments. The chapter concludes with a section on how to interpret time to failure, threshold stress, percent survival, stress intensity, and propagation rate data, and assess the precision of the associated tests.