Ferroalloys Alloying Additives Handbook

The word ferroalloy refers to an alloy of iron containing a significant proportion of one or more other elements like silicon, manganese, chromium, aluminum, or titanium. The main applications of ferroalloys occur in the steelmaking process. They are added to steel to improve properties like strength, ductility, and fatigue or corrosion resistance. Additionally, ferroalloys can have several other tasks, such as in refining, deoxidation, modification, and control of nonmetallic inclusions and precipitates. The production and role of ferroalloys are briefly introduced, both from a historical perspective and in light of current and future prospects. Examples of production figures, producers, and markets are presented. Recent developments and main drivers in ferroalloys processing, including energy saving, environmental issues, primary and secondary raw materials resources, and development trends in technology, are briefly discussed.

This chapter deals with ferroalloys as well as several alloying elements (complex ferroalloys) that are normally used as efficient steel and alloy deoxidizers. Some other minor ferroalloys and master alloys (including those intended for nonferrous applications) are also described in brief. The emphasis is on alloy composition, processing, and applications, because raw materials, the reduction process, and the peculiarities of the behavior of specific elements are discussed in relevant chapters. The exothermic ferroalloy mixtures and their application are also presented.

This chapter deals with tungsten and its ferroalloy technology. An overview of tungsten is presented, its properties are described, and reactions with other elements and compounds are outlined with major relevant phase equilibria diagrams. The raw materials, sources, and methods for reducing tungsten are presented. Different technologies for smelting ferrotungsten alloy are described.

The metallurgical processing of ferroalloys is based on a coherent combination of many scientific fields, which are briefly outlined in this chapter. The metal’s recovery process is based on reduction reactions, where metallurgical thermodynamics and kinetics are of a paramount importance. This includes the knowledge and ability to calculate, monitor, and change the formation of solutions and phases, rate of the reactions, and handling of reaction products in the most efficient way. In parallel, theoretical and engineering data on heat, mass, momentum, and charge transfer are critical for the development and design of ferroalloy production processes and furnaces. The chapter also discusses the basics of the structure and properties of metal and oxide (slag) when melted together with carbon reductants.