This appendix contains tables listing the chemical compositions of standard carbon H-steels and standard carbon boron H-steels and the hardenability characteristics of alloys.

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.

This chapter explains the definition of carbon steels and lists the Unified Numbering System designations and the compositions that are universally accepted by steel producers and fabricators. Compositions of higher hardenability carbon steels (higher manganese grades and/or boron treated steels) are also discussed, as well as those of free-machining carbon steels. Detailed heat treating procedures are presented for a representative group of carbon steels. The processes involved in tempering and austempering of carbon steels are also discussed.

This chapter examines the isothermal phase transformations of the iron-carbide system. The discussion includes the formation of ferritic, eutectoid, hypoeutectoid, hypereutectoid, bainitic, and martensitic microstructures as well as their properties, composition, and metallurgy. The use of time-temperature-transformation (TTT) diagrams in understanding the phase transformations and the changes in the isothermal transformation curves due to the addition of carbon and other alloying elements are also discussed.

This chapter discusses various processes involved in the production of steel from raw materials to finished mill products. The processes include hot rolling, cold rolling, forging, extruding, or drawing. The chapter provides a detailed description of two main furnaces used for making steel: the electric arc furnace and the basic oxygen furnace. It also provides information on the classification and specifications for various steels, namely, plain carbon steels, low-carbon steels, medium-carbon plain carbon steels, and high-carbon plain carbon steels. The chapter concludes with a general overview of the factors influencing corrosion in iron and steel and a brief discussion of corrosion-resistant coatings.

This chapter addresses the issue of stress-corrosion cracking (SCC) in carbon and low-alloy steels. It discusses crack initiation, propagation, and fracture in aqueous chloride, hydrogen sulfide, sulfuric acid, hydroxide, ammonia, nitrate, ethanol, methanol, and hydrogen gas environments. It explains how composition and microstructure influence SCC, as do mechanical properties such as strength and fracture toughness and processes such as welding and cold work. It also discusses the role of materials selection and best practices for welding.

This article discusses the role of alloying in the production and use of carbon and low-alloy steels. It explains how steels are defined and selected based on alloy content and provides composition and property data for a wide range of designations and grades. It describes the effect of alloying on structure and composition and explains how alloy content can be controlled to optimize properties and behaviors such as ductility, strength, toughness, fatigue and fracture resistance, and resistance to corrosion, wear, and high-temperature creep. It also examines the effect of alloying on processing characteristics such as hardenability, formability, weldability, machinability, and temper embrittlement. In addition, the article provides an extensive amount of engineering data with relevance in materials selection.

This chapter describes the designations of carbon and low-alloy steels and their general characteristics in terms of their response to hardening and mechanical properties. The steels covered are low-carbon steels, higher manganese carbon steels, boron-treated carbon steels, H-steels, free-machining carbon steels, low-alloy manganese steels, low-alloy molybdenum steels, low-alloy chromium-molybdenum steels, low-alloy nickel-chromium-molybdenum steels, low-alloy nickel-molybdenum steels, low-alloy chromium steels, and low-alloy silicon-manganese steels. The chapter provides information on residual elements, microalloying, grain refinement, mechanical properties, and grain size of these steels. In addition, the effects of free-machining additives are also discussed.

Heat treatment of steel involves a number of processes to condition the microstructure and obtain desired properties. This includes various methods namely, annealing, normalizing, and hardening by quenching and tempering. This chapter focuses on general heat treatment procedures and the applications of particular types or grades of carbon and low-alloy steels. The discussion covers carbon steel classification for heat treating, tempering of quenched carbon steels, and austempering of steel. In addition, the chapter discusses the effects of alloying and hardenability on steel and provides information on martempering of steel.