Search Results for high-alloy white iron

This article discusses the production, properties, and uses of high-alloy white irons. It explains how the composition and melt are controlled to produce a large volume of eutectic carbides, making these irons particularly hard and resistant to wear, and how the metallic matrix supporting the carbide phase can be adjusted via alloy content and heat treatment to optimize the balance between abrasion resistance and impact toughness. It also describes the effect of alloying elements and inoculants on various properties and behaviors and provides information on commercial alloy grades and applications.

This chapter covers mechanical properties, microstructures, chemical compositions, manufacturing processes, and engineering of gating practices for several applications of gray, white, and alloyed cast irons. It begins with a description of material standards, followed by a section providing information on the practice of stress relieving. Next, the chapter details various ways of eliminating slag entrainment while designing gating and venting systems. Several factors related to the establishment of the optimum pouring rate and time are then covered. Further, the chapter discusses the technology of unalloyed or low-alloyed gray iron castings and white iron and high-alloyed cast irons. Finally, it describes the casting defects that are associated with cast iron and the processes involved in solving these defects. The article includes a number of figures illustrating the topics discussed.

The properties of cast iron are determined primarily by the form of carbon they contain, which in turn, is controlled by modifying compositions and cooling rates during casting. Certain alloys (such as Si, Al, Ni, Co, and Cu) promote graphite formation, while others (such as S, V, Cr, Sn, Mo, and Mn) promote the formation of cementite. This chapter examines the relative potencies of these alloys and their effect on microstructure. It covers the five most common commercial cast irons, including white, gray, ductile, malleable, and compacted graphite, describing their compositional ranges, distinguishing features, advantages, limitations, and applications.

This chapter covers the friction and wear behaviors of cast irons. It describes the microstructure and metallurgy of gray, white, malleable, and ductile cast irons, their respective tensile properties, and their suitability for applications involving friction, various types of erosion, and adhesive and abrasive wear.

The commercial relevance of cast irons is best understood in the context of the iron-carbon phase diagram, where their composition places them near the eutectic point, which sheds light on why they melt at lower temperatures than steel and why they can be cast into more intricate shapes. This chapter examines these unique properties and how they are derived. It begins by describing the basic metallurgy of cast iron, focusing on the eutectic reaction. It explains how to control the reaction and thus properties of cast iron by overcooling and inoculation. The chapter also discusses composition, microstructure, heat treatments, and the classification and casting characteristics of white, gray, ductile, malleable, compacted graphite, and special cast irons.

This chapter introduces the metallographer to the various types of steels and cast irons and explains how they are classified and defined. Classification and designation details are provided for plain carbon steels, alloy steels, and gray, white, ductile, and malleable cast irons.

This article explains how malleable iron is produced and how its microstructure and properties differ from those of gray and ductile iron. Malleable iron is first cast as white iron then annealed to convert the iron carbide into irregularly shaped graphite particles called temper carbon. Although malleable iron has largely been replaced by ductile iron, the article explains that it is still sometimes preferred for thin-section castings that require maximum machinability and wear resistance. The article also discusses the annealing and alloying processes by which these properties are achieved.

This chapter discusses the composition, properties, microstructure, grain formation, and fracture behavior of gray, white, ductile, and malleable cast iron and how these critical factors are affected when iron is heated to different temperatures prior to or during solidification.

Malleable iron has unique properties that justify its application in the metal working industry. This chapter discusses the advantages, limitations, and mechanical properties of malleable iron; provides a description of the malleabilization process; and presents manufacturing guidelines for malleable iron castings.

This chapter discusses the crystal structures of steel and cast iron, the iron-iron carbide equilibrium diagram, microconstituents or phases in the iron-iron carbide phase diagram, the iron-carbon carbide-silicon equilibrium diagram of cast irons, and the influence on microstructure by base elements and alloying elements. Graphitization, cooling rates, and heat treatment effects are covered. There also is discussion on inoculation benefits, flake graphite types and typical applications, evolution of cast iron types, ASTM specification A247 for graphite shapes, and selection of the best molding process. A large table lists typical material choices for various applications.

This chapter discusses ferrous metals, including low-carbon steels, stainless steels, and cast irons. It also provides information on hardening and hardenability and the tempering process.

This chapter discusses the effect of composition and cooling rate on the microstructure and properties of cast irons and explains how they differ from steel. It describes the conditions under which white, gray, mottled (chilled), and nodular (ductile) cast irons are produced, and examines the growth mechanisms and structural details that set them apart. It also discusses the formation of compacted (vermicular) graphite and malleable iron, and compares and contrasts the composition, properties, and heat treatment of whiteheart and blackheart malleable types.

This chapter introduces the basic ferrous physical metallurgy principles that need to be understood by the metallographer. The discussion focuses on the variations in microstructures that are generated as a result of the phase transformations that occur during both heat treatment (as in steels) and solidification (as in cast irons). The chapter describes how the development of the iron-carbon phase diagram, coupled with the understanding of the kinetics of phase transformations through the use of isothermal transformation diagram, were breakthroughs in the advancement of ferrous physical metallurgy. Several examples of the morphological features of microstructural constituents in steels are also presented.

This chapter is a detailed account of heat treating techniques for cast irons (gray and ductile), providing the reader with a basic understanding of the differences among various types of cast irons and the concept of carbon equivalent. The types of heat treatments discussed are stress relieving, annealing, normalizing, surface hardening, quenching, martempering, austempering, and flame and induction hardening.

This chapter provides a detailed account of the development of tool steel technology. It begins with a record of steelmaking in ancient and medieval times. The crucible melting process involved in making steel is then discussed. This is followed by a description of the increasing use of alloys for tool steels. The chapter provides information on the research investigations into the metallurgy of high-speed tool steels at MIT, Union Carbide, and Carbon Laboratories. The major research effort involved in substituting molybdenum for tungsten in high-speed tool steels is discussed. The chapter also describes the role of the Cleveland Twist Drill Company as the first adopter of molybdenum high-speed steel. It ends with a discussion on the advanced work on high-speed steels by Swedish researchers.

Tool steels are the ferrous alloys used to manufacture tools, dies, and molds that shape, form, and cut other materials, including steels, nonferrous metals, and plastics. This chapter explores the considerations that make tool steels a very special class of steels, the long historical evolution of iron and steel manufacture, including steels for tools, and the development of tool steels as they emerged from the general class of iron and steel products.

Several limitations in achieving optimal gear performance with conventional nitriding have led researchers to work on a variety of novel and improved nitriding processes. Of these, ion/plasma nitriding offers some promising results, which are reviewed in this chapter. The chapter concludes with a case history describing the application of ion nitriding to an internal ring gear of an epicyclic gearbox.

This chapter provides the definitions of fundamental wear mechanisms. The chapter describes the properties and applications of materials used for wear resistance. It discusses the processes involved in screening tests for wear resistance. In addition, the practical application of wear-resistant principles is covered.