The various methods of furnace, torch, induction, resistance, dip, and laser brazing are used to produce a wide range of highly reliable brazed assemblies. However, imperfections that can lead to braze failure may result if proper attention is not paid to the physical properties of the material, joint design, prebraze cleaning, brazing procedures, postbraze cleaning, and quality control. Factors that must be considered include brazeability of the base metals; joint design and fit-up; filler-metal selection; prebraze cleaning; brazing temperature, time, atmosphere, or flux; conditions of the faying surfaces; postbraze cleaning; and service conditions. This article focuses on the advantages, limitations, sources of failure, and anomalies resulting from the brazing process. It discusses the processes involved in the testing and inspection required of the braze joint or assembly.

This article provides information on the application of nondestructive examination (NDE) technologies to tube and pipe products. These include modeling and simulation methods, eddy-current methods, magnetic methods, acoustic methods, and physical methods. A summary of nondestructive examination methods based on flaw type and product stage is presented in a table. The article also discusses in-service inspection of tubular products and presents an example that illustrates the importance of nondestructive testing (NDT) for welds in austenitic stainless steel tubing.

Stainless steels are characterized as having relatively poor wear resistance and tribological properties, but they are often required for a particular application because of their corrosion resistance. This article describes the classification of stainless steels and wear. Stainless steels have been classified by microstructure and are categorized as austenitic, martensitic, ferritic, or duplex. The main categories of wear are related to abrasion, erosion, adhesive wear, and surface fatigue. The article presents a list that proposes the alloy family that could be the optimal selection for a particular wear mode. The corrosion modes include dry sliding, tribocorrosion, erosion, erosion-corrosion, cavitation, dry erosion, erosion-oxidation, galling and fretting.

Stainless steels are primarily alloys of iron and chromium. They are grouped into five families, primarily based on their microstructure: ferritic, austenitic, martensitic, duplex, and precipitation hardening. Three out of the five families of stainless steels, namely, austenitic, ferritic, and martensitic, are well suited for manufacture via conventional powder metallurgy (PM) processes. This article presents the iron-chromium partial phase diagram to illustrate the changes in the temperature range when pure iron is alloyed with chromium. It describes AISI and UNS numbering systems, which are used as an identification system for stainless steels. The article tabulates the material designations of stainless steels in accordance with the Metal Powder Industries Federation. It also details the characteristics and chemical composition of wrought and PM 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.

Precipitation hardening is a hardening mechanism found in various steels and alloy systems, such as nickel-, cobalt-, titanium-, copper-, and iron-base alloys. This article provides a brief description of precipitation hardening process, furnace equipment, surface-related problems, and protective atmospheres used in heat treatment of iron-base precipitation-hardenable (PH) superalloys. It focuses on various factors to be considered in heat treating of PH stainless steels: cleaning prior to heat treatment, furnace atmospheres, time-temperature cycles, variations in cycles, and scale removal after heat treatment. The article describes the mechanical properties, solution treatment, and aging treatment for many martensitic PH alloys, including: Alloy 17-4 PH, Alloy 13-8 Mo, Alloy 15-5 PH, Custom 450, and Custom 455; as well as semiaustenitic PH stainless steels such as Alloy 17-7 PH, Alloy PH 15-7 Mo, AM-350, Pyromet 350, AM-355, and Pyromet 355; austenitic PH stainless steel, A-286; cast PH stainless steels; and iron-nickel PH superalloys.

Low-temperature carburization hardens the surface of austenitic stainless steels through the diffusion of interstitial carbon without the formation of carbides. This article provides an overview on austenitic stainless steels and low-temperature carburization. It reviews the competing technologies and commercial application of low-temperature carburization. The article discusses several processing parameters, including activation of the surface, proper surface preparation, selection and condition of the alloy to be carburized, treatment temperature, and carburizing atmosphere for successful low-temperature carburization of austenitic stainless steels and other chromium-containing alloys. It describes the performance properties of the low-temperature carburized layer: fatigue resistance, wear resistance, erosion resistance, and corrosion resistance.

This article provides information on the metallurgy of austenitic stainless steels, and the formation of their intermediate phases (Sigma, Chi, and Laves). It discusses sensitization, a major problem associated with the austenitics, and solutions to avoid the problem. The article describes heat treatments applied to austenitic stainless steels, namely, soaking for homogenization and preparation for hot working; annealing to remove the effects of cold work and to put alloying elements into solid solution; and stress relieving. It provides information on the stabilizing anneal process, which is conducted on stabilized alloys, and discusses the metallurgical characteristics of austenitic stainless steels that may affect the selection of a stress-relieving treatment and prevention of stress corrosion by stress relieving. The article also discusses the heat treatments applied to duplex stainless steels, which involve soaking and annealing, achieving the austenite-ferrite balance, precipitation of intermetallics, and alpha prime precipitation.

Low-temperature surface hardening is mostly applied to austenitic stainless steels when a combination of excellent corrosion performance and wear performance is required. This article provides a brief history of low-temperature surface hardening of stainless steel, followed by a discussion on physical metallurgy, including crystallographic identity, thermal stability and decomposition, nitrogen and carbon solubility in expanded austenite, and diffusion kinetics of interstitials. It provides a description of low-temperature nitriding and nitrocarburizing processes for primarily austenitic and, to a lesser extent, other types of stainless steels along with practical examples and industrial applications of these steels.

Stainless steels are essential for the modern industrial civilization because of their corrosion resistance, especially in the chemical, petrochemical, and food industries. This article discusses the classification of the various types of stainless steels, including martensitic, ferritic, austenitic, duplex (ferritic-austenitic), and precipitation-hardening stainless steels. It presents a checklist of characteristics to be considered in selecting the proper type of stainless steel for a specific application. The article also outlines the need to promote the formation of an effective protective passive layer in stainless steels. It discusses hardness, fatigue and fretting properties, tribological properties, wear resistance, and corrosion-wear process of the S-phase layer. The article describes two thermochemical nitriding techniques of stainless steels: plasma-assisted nitriding techniques and non-plasma assisted nitriding processes. It also describes the difficulties in stainless steel nitriding/carburizing.

Stainless steels are used for medical implants and surgical tools due to the excellent combination of properties, such as cost, strength, corrosion resistance, and ease of cleaning. This article describes the classifications of stainless steels, such as austenitic stainless steels, martensitic stainless steels, ferritic stainless steels, precipitation-hardening stainless steels, and duplex stainless steels. It contains a table that lists common medical device applications for stainless steels. The article discusses the physical metallurgy and physical and mechanical properties of stainless steels. Medical device considerations for stainless steels, such as fatigue strength, corrosion resistance, and passivation techniques, are reviewed. The article explains the process features of implant-grade stainless steels, including type 316L, type 316LVM, nitrogen-strengthened, ASTM F1314, ASTM F1586, ASTM F2229, and ASTM F2581 stainless steels.

This article lists the system parameters of the friction welding process and describes the four categories of monitoring and control of the manufacturing process. It discusses the monitoring methods of a rotary friction welded sample, for determining in-process quality of ferrous alloys, and dissimilar metals using acoustic emission. The article reviews the feasibility of detecting the presence of ferrite during microstructural evolution of friction welding of three austenitic stainless steels: 310, 304, and 255. It also explains the in-process quality control of friction welding.

Materials of construction for equipment and piping in pharmaceutical processing plants must be resistant to corrosion from the high-purity water, the buffer solutions used in preparation of the products, and the cleaning solutions used to maintain the purity of the product. The primary water used in pharmaceutical production is water for injection (WFI). This article presents the steps for preparing WFI and discusses the effect of chlorides on stainless steel. It provides information on the passive layer of stainless steels and chromium-containing nickel alloys. The article provides information on the surface finish of pharmaceutical equipment. It discusses the classification of rouge and the characteristics of cast type 316L stainless steel. The article also explains how and when to perform cleaning and repassivation process on classes of rouge.

This article describes the selection of materials for the production and handling equipment of concentrated sulfuric acid, depending on factors such as the allowable corrosion rate, desired mechanical and physical properties, fabrication requirements, availability, and cost. Materials such as carbon steel, cast irons, austenitic stainless steels, higher austenitic stainless steels, higher chromium Fe-Ni-Mo alloys, nickel-base alloys, non-metals, and specific other metals and alloys are also discussed.

This article discusses the main materials and water chemistry characteristics of the primary and secondary water circuits of a pressurized water reactor (PWR). It reviews the corrosion issues of PWR materials and the influence of corrosion and fouling on primary and secondary circuit radiation fields. The article explains the primary side intergranular stress corrosion cracking (IGSCC) in different materials, namely, nickel-base alloys, high-strength nickel-base alloys, low-strength austenitic stainless steels, and high-strength stainless steels. The secondary side corrosion in steam generator including denting, pitting, intergranular attack and IGSCC is also discussed. The article examines laboratory studies that have resulted in models and computer codes for evaluating and predicting intergranular corrosion, and considers the remedial actions for preventing or arresting intergranular corrosion. It concludes with information on the external bolting corrosion in nuclear power reactors.

Hydrochloric acid (HCl) may contain traces of impurities that will change the aggressiveness of the solution. This article discusses the effects of impurities such as fluorides, ferric salts, cupric salts, chlorine, and organic solvents, in HCl. It describes the corrosion resistance of various metals and alloys in HCl, including carbon and alloy steels, austenitic stainless steels, standard ferritic stainless steels, nickel and nickel alloys, copper and copper alloys, corrosion-resistant cast iron, zirconium, titanium and titanium alloys, tantalum and its alloys, and noble metals. The article illustrates the effect of HCl on nonmetallic materials such as natural rubber, neoprene, thermoplastics, and reinforced thermoset plastics. It also tabulates the corrosion of various metals in dry hydrogen chloride.

This article provides the corrosion data for materials in hydrofluoric acid (HF) and anhydrous hydrogen fluoride (AHF). These materials include carbon and low-alloy steels, austenitic stainless steels, nickel-rich austenitic stainless steels, nickel and nickel-base alloys, copper alloys, precious metals, and non-metals. The article also discusses the hydrogen blistering and stress-corrosion cracking of carbon steels in high-temperature HF and AHF.

This article discusses the corrosion characteristics of superaustenitic stainless and duplex stainless steels, which are used in pharmaceutical industry. It describes passivation treatments and the electropolishing of stainless steels. The article informs that electropolishing is not a passivation treatment, although the proper execution of the process will result in a passive surface. The article concludes with a discussion on roughing, which is a phenomenon of particular interest to the pharmaceutical industry.

Stainless steels, based on forging pressure and load requirements, are more difficult to forge because of the greater strength at elevated temperatures and the limitations on the maximum temperatures at which stainless steels can be forged without incurring microstructural damage. This article discusses the forging methods, primary mill practices (primary forging and ingot breakdown), trimming, and cleaning operations of stainless steels. It describes the use of forging equipment, dies, and die material in the forging operation. The article provides an overview of the forgeability of austenitic stainless steels, martensitic stainless steels, precipitation-hardening stainless steels, and ferritic stainless steels. It concludes with a discussion on the heating and lubrication of dies.

This article provides an overview of the identification systems for various grades of wrought stainless steels, namely, the American Iron and Steel Institute numbering system, the Unified Numbering System, and proprietary designations. It elaborates on five major families of stainless steels, as defined by the crystallographic structure. These include ferritic stainless steels, austenitic stainless steels, martensitic stainless steels, and precipitation-hardening stainless steels. The mechanism of corrosion protection for stainless steels is reviewed. The article examines the effects of composition, processing, design, fabrication, and external treatments on the corrosion of stainless steels. Various forms of corrosion, namely, general, galvanic, pitting, crevice, intergranular, stress-corrosion cracking, erosion-corrosion, and oxidation, are reviewed. Corrosion testing for; corrosion in atmosphere, water, and chemical environments; and the applications of stainless steels in various industries are also discussed.