Search Results for UNS S31803

This article provides information on the base material properties of wrought duplex stainless steels (DSS). These properties include microstructure, alloy grades, mechanical and physical properties, and corrosion resistance. The article reviews the applications and microstructural development of DSS. It describes the factors influencing welding and weldability of the DSS. These factors include preheating, postweld heat treatment, interpass temperature control, welding practices, welding procedure qualification, filler metal requirements, cracking behavior, and loss of properties. The article examines the applicable welding processes such as fusion welding and solid-state welding processes.

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.

Phosphoric acid is less corrosive than sulfuric and hydrochloric acids. This article discusses the corrosion rates of metal alloys in phosphoric acid, including aluminum, carbon steel and cast irons, stainless steels, nickel-rich G-type alloys, copper and copper alloys, nickel alloys, lead, titanium alloys, and zirconium alloys. Nonmetallic materials may be chemically attacked in some corrosive environments, which can result in swelling, hardening, or softening phenomena; extraction of ingredients; chemical conversion of the nonmetallic constituents; cross-linking oxidation; and/or substitution reactions. The article also describes the corrosion resistance of nonmetallic materials such as rubber and elastomeric materials, plastics, carbon and graphite, and ceramic materials.

This article outlines the processes by which materials are selected to prevent or control localized corrosion, galvanic corrosion, and intergranular corrosion. It reviews the operating conditions and the design of candidate materials for material selection. The article discusses various corrosion-resistant materials, including ferrous and nonferrous metals and alloys, thermoplastics, reinforced thermosetting plastics, nonmetallic linings, glass, carbon and graphite, and catalyzed resin coatings. It examines an unusual form of intergranular corrosion known as exfoliation, which occurs in aluminum-copper alloys. The article also describes three types of erosion-corrosion: liquid erosion-corrosion, cavitation, and fretting. It concludes with information on the various factors to be considered for material selection, including minimum cost or economic design, minimum corrosion, minimum investment, and minimum maintenance.

Crevice corrosion is a form of localized corrosion that affects many alloys that normally exhibit passive behavior. This article discusses the frequently used crevice corrosion testing and evaluation procedures. These procedures include specific crevice corrosion tests, multiple-crevice assembly tests, cylindrical materials and products evaluation, component testing, electrochemical tests, and mathematical modeling.

This article begins with a discussion on the components and importance of flue gas desulfurization (FGD) technology used in power plant for pollution control. It further discusses the corrosion problems encountered in different operating zones of FGD system and the major forms of corrosive attack encountered in those zones, including crevice corrosion, pitting corrosion, and acid attack. The article concludes with information on the materials selection and design features for minimizing the possibility of corrosion.

The machinability of stainless steels varies from low to very high, depending on the final choice of the alloy. This article discusses general material and machining characteristics of stainless steel. It briefly describes the classes of stainless steel, such as ferritic, martensitic, austenitic, duplex, and precipitation-hardenable alloys. The article examines the role of additives, such as sulfur, selenium, tellurium, lead, bismuth, and certain oxides, in improving machining performance. It provides ways to minimize difficulties involved in the traditional machining of stainless steels. The article describes turning, drilling, tapping, milling, broaching, reaming, and grinding operations on stainless steel. It concludes with information on some of the nontraditional machining techniques, including abrasive jet machining, abrasive waterjet machining electrochemical machining, electron beam machining, and plasma arc machining.

This article discusses the materials of construction found in pharmaceutical production facilities. The materials discussed are different stainless steels, nickel and nickel-base alloys, titanium, zirconium, impervious graphite, fluoropolymers, and glass-lined steel. The article describes the three primary causes of failure in the manufacture of pharmaceuticals: embedded iron, failures of glass linings, and corrosion under thermal insulation.

Stainless steels are iron-base alloys containing minimum of approximately 11% Cr, and owing to its excellent corrosion resistance, are used for wide range of applications. These applications include nuclear reactor vessels, heat exchangers, oil industry tubular, chemical processing components, pulp and paper industries, furnace parts, and boilers used in fossil fuel electric power plants. The article provides a brief introduction on corrosion resistance of wrought stainless steel and its designations. It lists the chemical composition and describes the physical and mechanical properties of five major stainless steel families, of which four are based on the crystallographic structure of the alloys, including martensitic, ferritic, austenitic, or duplex. The fifth is precipitation-hardenable alloys, based on the type of heat treatment used. The article further discusses the factors in the selection of stainless steel, namely corrosion resistance, fabrication characteristics, product forms, thermally induced embrittlement, mechanical properties in specific temperature ranges, and product cost.

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.

This article reviews the influence of local strains and corrosion fatigue on the initiation of fatigue cracks in duplex stainless steels. It provides useful information on fatigue crack growth, fatigue strength, and fracture toughness of duplex stainless steels. The article discusses the fatigue and fracture behavior of duplex stainless steels during stress-corrosion cracking. It details the elevated-temperature properties of duplex stainless steels, such as creep-fatigue behavior and thermal cycling properties.

This article focuses on the corrosion and deterioration of components on recreational and small workboats. It discusses the materials selection and corrosion control for the components. These components include hulls, fittings, fasteners, metal deck gear, winches, backing plates, lifeline supports, inboard engines, cooling systems, propulsion systems, electrical and electronic systems, plumbing systems, masts, spars, and rigging.

This article discusses the composition, characteristics, and properties of the five groups of wrought stainless steels: martensitic stainless steels, ferritic stainless steels, austenitic stainless steels, duplex stainless steels, and precipitation-hardening stainless steels. The selection of stainless steels may be based on corrosion resistance, fabrication characteristics, availability, mechanical properties in specific temperature ranges and product cost. The fabrication characteristics of stainless steels include formability, forgeability, machinability, and weldability. The product forms of wrought stainless steels are plate, sheet, strip, foil, bar, wire, semifinished products, pipes, tubes, and tubing. The article describes tensile properties, elevated-temperature properties, subzero-temperature properties, physical properties, corrosion properties, and fatigue strength of stainless steels. It characterizes the experience of a few industrial sectors according to the corrosion problems most frequently encountered and suggests appropriate grade selections. Corrosion testing, surface finishing, mill finishes, and interim surface protection of stainless steels are also discussed.

This article focuses on microbiologically influenced corrosion (MIC) of military assets. It discusses the mechanisms of MIC in hydrocarbon fuels and atmospheric, immersion, and buried environments with specific examples. The article describes the behavior of metals and alloys, namely, copper alloy, nickel alloy, titanium and titanium alloys, aluminum alloys, stainless steels, and carbon steel in immersion environments.

Metallurgical variables, mainly carbon distribution and the presence of nitrogen and metallic phases, can influence the corrosion behavior of austenitic, ferritic, duplex, and martensitic stainless steels. This article describes the effects of these metallurgical and processing variables on the susceptibility of the stainless steels to intergranular corrosion and intergranular stress-corrosion cracking and their testing methods. It explains the effect of sigma and related phases on the corrosion behavior of stainless steels.

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.

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.

Selection of appropriate grades of steel will enable the steel to perform for very long times with minimal corrosion, but an inadequate grade can corrode and perforate more rapidly than a plain carbon steel will fail by uniform corrosion. This article describes the effect of chemical composition, heat treatment, welding, and surface condition on corrosion resistance of stainless steels. It discusses the various forms of corrosion and the important factors to be considered when selecting suitable stainless steel for application in specific corrosive environments.

This article focuses on the effects of microscopic organisms and the by-products they produce on the electrochemical corrosion of metals. The general characteristics of the microorganisms that facilitate their influence on the electrochemistry of corrosion are discussed. The industries most often reported as being affected by microbiological corrosion are listed, along with the organisms usually implicated in the attack. The article explains that the influence of organisms can be addressed successfully for a corrosion control program by using four types of evidence: metallurgical, microbiological, chemical, and electrochemical. It provides information on the microbiologically influenced corrosion (MIC) of irons and steels, passive alloys (austenitic stainless steels), aluminum alloys, copper alloys, and composites. The article reviews the formation of microbial biofilms and macrofouling films. It also describes the general approaches taken to prevent MIC.