This article describes the physical properties of powder metallurgy (PM) stainless steels. These include thermal diffusivity, conductivity, thermal expansion coefficient, Poisson's ratio, and elastic modulus. The article contains a table that lists the characteristics of various grades of PM stainless steels. It discusses the applications of various PM stainless steels such as rearview mirror brackets, anti-lock brake system sensor rings, and automotive exhaust flanges and sensor bosses.

Stainless steels are highly alloyed materials in comparison to most other popular powder metallurgy (PM) materials, such as low-alloy steels, copper alloys, and aluminum alloys. This article provides an overview of the history of PM stainless steels.

Steel automotive exhaust systems suffer from various forms of corrosion. This article illustrates exhaust system components with typical upper metal skin temperatures and alloys of construction. It discusses high-temperature corrosion of automotive exhaust systems, including oxidation, hot salt attack, and thermal fatigue. The article describes the various forms of corrosion which occur at the cold end of an exhaust system. The forms of cold end exhaust corrosion, including condensate pitting corrosion, exterior salt pitting, crevice corrosion, intergranular corrosion, and galvanic corrosion.

Powder metallurgy (PM) stainless steels, as with conventional PM steels, are often used in the as-sintered condition. In addition to cost considerations, minimization of postsinter handling and secondary operations is also preferred because it reduces the potential for contamination of the parts with particulates and residues, which can result in the appearance of surface rust. This article provides information on various secondary operations, including tumbling, re-pressing, resin impregnation, annealing or heat treating, brazing, machining, and welding. It describes those aspects relating to welding of PM stainless steels, specifically, the effects of density, residual porosity, and sintered chemistry on weldability. Further, the article investigates the influence the sintering atmosphere has on machinability, as well as differences created by the presence of residual porosity.

This article describes the factors influencing the room-temperature and elevated-temperature mechanical properties of powder metallurgy (PM) stainless steels. It contains tables that list the mechanical property specifications of the Metal Powder Industries Federation (MPIF) Standard 35.

Welded connections are a common location for failures for many reasons, as explained in this article. This article looks at such failures from a holistic perspective. It discusses the interaction of manufacturing-related cracking and service failures and primarily deals with failures that occur in service due to stresses caused by externally applied loads. The purpose of this article is to enable a failure analyst to identify the causative factors that lead to welded connection failure and to identify the corrective actions needed to overcome such failures in the future. Additionally, the reader will learn from the mistakes of others and use principles that will avoid the occurrence of similar failures in the future. The topics covered include failure analysis fundamentals, welded connections failure analysis, welded connections and discontinuities, and fatigue. In addition, several case studies that demonstrate how a holistic approach to failure analysis is necessary are presented.

Titanium has been recognized as an element with good mechanical and physical properties, alloying characteristics, and corrosion resistance. Providing an outline of general characteristics and types of titanium alloys, this article discusses the contemporary technology of titanium along with its market developments. It also discusses the application of titanium and titanium alloys in corrosive environments and in aerospace and automotive industries. The article describes the developments in titanium processing and materials technologies, which include the development of sponge production and melting processes, oxide dispersion-strengthened alloys by powder metallurgy techniques, titanium-base intermetallic compounds, and titanium-matrix composites.

This article characterizes the physical differences between powder metallurgy (PM) and wrought or cast materials, as they apply to joining. It discusses acceptable joining procedures and techniques, including welding and brazing and solid-state methods. Information on the weldability of various PM materials is presented. The article also describes the effects of porosity on several important properties that affect the welding characteristics.

This article is a pictorial guide to forms of corrosion that draws attention to common pitfalls or situations that have caused premature corrosion, sometimes with expensive consequences. The examples used are not exhaustive; they highlight the necessity to fully examine materials, conditions, and specific circumstances that together can reduce the anticipated service life of a component or plant. The color images in this article are categorized according to the type of corrosion following the general order that is adopted in Volume 13A of ASM Handbook. The first table of the article provides a categorization of the forms of corrosion. It also provides a reference to articles or sections of articles in Volume 13A that detail the particular corrosion form or mechanism. The second table is a guide listing the figures in this article by material and by the corrosion form or mechanism illustrated.

This article discusses the selection of types of stainless steel for various methods of forming based on the formability and on the power required for forming. It reviews the requirements of lubrication, blanking, and piercing. The article describes various forming methods, namely, press-brake forming, press forming, multiple-slide forming, deep drawing, spinning, rubber-pad forming, drop hammer forming¸ three-roll forming, contour roll forming, stretch forming, and bending of tubing.

Structural applications for advanced ceramics include mineral processing equipment, machine tools, wear components, heat exchangers, automotive products, aerospace components, and medical products. This article begins with an overview of the wear-resistant applications and the parameters affecting wear of ceramics, namely, hardness, thermal conductivity, fracture toughness, and corrosion resistance. The next part of the article addresses temperature-resistant applications of advanced ceramics. Specific applications of ceramic materials addressed include cutting tools, pump and valve components, rolling elements and bearings, paper and wire manufacturing, biomedical implants, heat exchangers, adiabatic diesel engines, advanced gas turbines, and aerospace applications.

This article discusses some of the factors that are linked directly to the casting design of ductile iron castings. It reviews the choice of molding process, application of draft, and patternmaker's allowance that should be taken into consideration in designing castings. The article describes the solidification shrinkage associated with the volume change that occurs during solidification, as well as strength and stiffness of ductile iron castings. It concludes with a discussion on the thermal deformation and residual stress in ductile iron castings.

The crucible induction furnace is growing as an alternative melting unit to the cupola furnace due to its low specific power and reduced power consumption during solid melting material. This article details the process engineering features of the crucible induction furnace. It discusses the various processes involved in melting, holding, and pouring of liquid melt in crucible induction furnaces wherein the holding operation is carried out in channel furnace and pouring operation in pressure-actuated pouring furnaces. The article examines the behavior of furnace refractory lining to defects such as erosion, infiltration, crack formation, and clogging, and the corresponding preventive measures to avoid the occurrence of these defects. It elucidates the overall furnace operations, including commissioning, operational procedures, automatic process monitoring, inductor change, and dealing with disturbances.

Stainless steel powder metallurgy (P/M) parts represent an important and growing segment of the P/M industry. This article describes the processing, properties, and composition of medium-density and high-density P/M stainless steels. Medium-density materials are processed by pressing and sintering prealloyed stainless powders. High-density materials are produced by hot isostatic pressing, cold isostatic pressing followed by extrusion, or metal injection molding. The comparison of mechanical properties of these P/M stainless steels is represented graphically. The article contains a table that lists the effect of iron, carbon, nitrogen, oxygen, and density on the corrosion resistance of the sintered austenitic stainless steels.

This article describes the sintering behavior of austenitic, ferritic, and martensitic stainless steels. It presents different sintering schedules that are selected by Metal Powder Industries Federation (MPIF). The article provides information on the equipment and atmospheres used for sintering and the steps involved in the process. It discusses the factors that influence the dimensional changes in sintering, namely, powder-related, compaction-related, and sintering-related factors.

Distortion failure occurs when a structure or component is deformed so that it can no longer support the load it was intended to carry. Every structure has a load limit beyond which it is considered unsafe or unreliable. Estimation of load limits is an important aspect of design and is commonly computed by classical design or limit analysis. This article discusses the common aspects of failure by distortion with suitable examples. Analysis of a distortion failure often must be thorough and rigorous to determine the root cause of failure and to specify proper corrective action. The article summarizes the general process of distortion failure analysis. It also discusses three types of distortion failures that provide useful insights into the problems of analyzing unusual mechanisms of distortion. These include elastic distortion, ratcheting, and inelastic cyclic buckling.

Distortion often is observed in the analysis of other types of failures, and consideration of the distortion can be an important part of the analysis. This article first considers that true distortion occurs when it was unexpected and in which the distortion is associated with a functional failure. Then, a more general consideration of distortion in failure analysis is introduced. Several common aspects of failure by distortion are discussed and suitable examples of distortion failures are presented for illustration. The article provides information on methods to compute load limits, errors in the specification of the material, and faulty process and their corrective measures to meet specifications. It discusses the general process of material failure analysis and special types of distortion and deformation failure.

Cores are separate shapes of sand that are placed in the mold to provide castings with contours, cavities, and passages that are not otherwise practical or physically obtainable by the mold. This article describes the basic principles of coremaking and the types of core sands, binders, and additives used in coremaking. It discusses the curing of compacted cores by core baking and the hot box processes. The article provides an overview of the core coatings, assembling and core setting, coring of tortuous passages, and cores in permanent mold castings and investment castings. It also discusses the design considerations in coremaking to eliminate cores and compares coring with drilling.