Search Results for high-alloy iron

Castability of alloys is a measure of their ability to be cast to a given shape with a given process without the formation of cracks/tears, pores/shrinkage, and/or other significant casting defects. This article discusses the factors which affect the fluidity of an iron melt: alloy composition and initial melt condition. Besides the basic alloy properties, the effective castability of high-alloy irons can be significantly improved through casting and casting system design. The article describes the product design and processing factors of high-alloy graphitic irons and high-alloy white irons. It explains the heat treatment of high-silicon irons for high-temperature service and concludes with a discussion on machining and finishing of high-alloy iron castings.

The high-alloy irons can be categorized into two main groups: the high-alloy graphitic irons (covering both gray and ductile grades) and the high-alloy white irons. High-alloy irons are used in applications with demanding requirements, such as high resistance to wear, heat, and corrosion, or for combined properties. This article discusses the specification and selection of high-alloy irons. The common alloying elements and their effect on the stable and metastable eutectic temperatures are listed in a table. The article provides information on the compositions, properties and applications of high-alloy graphitic irons and high-alloy white irons.

This article presents a discussion on the melting, pouring, and shakeout practices; composition control; molds, patterns, and casting design; heat treatment; and applications of different classes of nickel-chromium white irons and high-chromium white irons.

This article discusses the melting and pouring practices, heat treatment, and applications of different types of high-alloy graphitic iron, namely, high-silicon gray irons, high-silicon ductile irons, nickel-alloyed austenitic irons, austenitic gray irons, austenitic ductile irons, and aluminum-alloyed irons.

High-alloy graphitic cast irons are used primarily in applications requiring corrosion resistance or strength and oxidation resistance in high-temperature service. This article describes the properties, applications and heat treatment processes of high-alloy graphitic cast irons, including austenitic gray irons and austenitic ductile irons. It also provides a discussion on the heat treatment of high-silicon irons for heat resisting and corrosion resisting applications.

Hardfacing is defined as the application of a wear-resistant material, in depth, to the vulnerable surfaces of a component by a weld overlay or thermal spray process Hardfacing materials include a wide variety of alloys, carbides, and combinations of these materials. Iron-base hardfacing alloys can be divided into pearlitic steels, austenitic (manganese) steels, martensitic steels, high-alloy irons, and austenitic stainless steel. The types of nonferrous hardfacing alloys include cobalt-base/carbide-type alloys, laves phase alloys, nickel-base/boride-type alloys, and bronze type alloys. Hardfacing applications for wear control vary widely, ranging from very severe abrasive wear service, such as rock crushing and pulverizing to applications to minimize metal-to-metal wear. This article discusses the types of hardfacing alloys, namely iron-base alloys, nonferrous alloys, and tungsten carbides, and their applications and advantages.

This article describes two contemporary approaches for preparing cast iron specimens with a wide range of phases and constituents as well as different graphite morphologies. It introduces concepts and preparation materials that enable metallographers to shorten the process while producing better, more consistent results. Recommended procedures to prepare cast irons and examples of high-alloy cast iron microstructures revealed using a variety of etchants are presented. Several etchants are used to reveal the matrix microstructure, depending on the alloy content. The article discusses the use of black and white etchants and lists the compositions of abrasion-resistant cast irons according to ASTM A532/A532M in a table.

This article introduces the general principles and applications of heat treatment to iron castings. It provides a detailed discussion on the heat treatment processes, namely, stress relieving, annealing, normalizing, throughhardening, and surface hardening for various types of cast irons. These include gray iron, ductile iron, compacted graphite iron, white iron, malleable iron, and high-alloy iron. The article describes how to control temperature and atmosphere during the heat treatment of the iron castings.

High-alloyed white cast irons are an important group of materials whose production must be considered separately from that of ordinary types of cast irons. The metallic matrix supporting the carbide phase in the high-alloy white cast irons can be adjusted by alloy content and heat treatment to develop proper balance between resistance to abrasion and toughness needed to withstand repeated impact. This article provides a brief discussion on the heat treatment, mechanical properties, and chemical compositions of high-alloy white cast irons such as nickel-chromium white irons and high-chromium white irons.

The high-alloyed white irons are primarily used for abrasion-resistant applications and are readily cast into the parts needed in machinery for crushing, grinding, and handling of abrasive materials. This article discusses three major groups of the high-alloy white cast irons: nickel-chromium white irons, chromium-molybdenum irons, and high-chromium white irons. Mechanical properties for three white irons representing each of these three general groups are presented as bar graphs. The article also describes the various heat treatments of a martensitic microstructure, including austenitization, quenching, tempering, annealing, and stress relieving.

Metals and alloy powders are used in welding, hardfacing, brazing, and soldering applications, which include hardface coatings, the manufacturing of welding stick electrodes and flux-cored wires, and additives in brazing pastes or creams. This article reviews these applications and the specific powder properties and characteristics they require.

Alloy cast irons are casting alloys based on the Fe-C-Si system that contain one or more alloying elements added to enhance one or more useful properties. This article discusses the composition of different types of alloy cast iron, including white cast irons, corrosion-resistant cast irons, heat-resistant cast irons, and abrasion-resistant cast irons. It provides information on the effect of the alloying element on their high-temperature properties. The article also discusses the microstructure and mechanical properties of alloy cast irons.