Metallic alloys that are typically used for medical purposes include stainless steels, Ti-6Al-4V, and Co-Cr-Mo. This article discusses the relative merits of each of these alloys. The utilization of stainless steels in the biomedical industry, especially in relation to the additive manufacturing (AM) process, is the main focus of this article. The characteristics of various stainless steels are described subsequently, and the categories that are of relevance to the biomedical industry are identified. The types of stainless steels covered are austenitic, ferritic, martensitic, duplex, and precipitation-hardened stainless steels. The article discusses the potential benefits of AM for biomedical devices. It describes the types of AM processes for stainless steels, namely binder jet, directed-energy deposition, and laser powder-bed fusion. The article reviews the AM of austenitic, martensitic, and PH stainless steels for biomedical applications. In addition, the challenges and obstacles to the clinical use of AM parts are covered.

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.

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 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.

This article reviews the metallurgical factors associated with welding. It provides a discussion on the preferential attack associated with weld metal precipitates in austenitic stainless steels. The article describes the corrosion associated with postweld and weld backing rings. The effects of gas-tungsten arc weld shielding gas composition and heat-tint oxides on corrosion resistance are also discussed. The article explains microbiological corrosion of butt welds in water tanks with the examples. In addition, it provides information on corrosion of ferritic stainless steel weldments and duplex stainless steel weldments.

Characteristics of stainless steel that affect its formability include yield strength, tensile strength, and ductility, in addition to the effect of work hardening on these properties. This article discusses the forming process of stainless steel, heat-resistant alloys and refractory metals, detailing the major aspects of forming, including formability, lubrication, and forming methods and tools. The effect of factors such as alloy condition, cold reduction, forming direction (in the case of heat-resistant alloys) and temperature (in the case of refractory metals) on formability is also discussed.

This article provides an overview of the compaction of metal powder in a rigid die and reviews the compaction characteristics of stainless steel powders, including green density, compressibility, green strength, apparent density, flow rate, and sintered density. It describes the influence of compaction characteristics of stainless steel powders in tool materials selection, lubrication, annealing, double pressing/double sintering, and warm compaction.

This article provides information on the process details that differ from general water atomization of metals as they relate to basic and engineering properties that are specific to stainless steel powders. The discussion focuses on the compacting-grade stainless steel powders. The process details include raw materials, melting method, and control of physical and chemical powder characteristics. The article describes the gas atomization of stainless steel powders and processes that are done after water atomization: drying, screening, annealing, and lubricating. It also discusses the two types of quality assurance testing measures for powder metallurgy stainless steels: tests for powder contamination and tests of chemical and physical properties.