Search Results for UNS N06617

Corrosion is often thought of as rusting, the process of deterioration undergone by a metal when it is exposed to air or water. This article provides the fundamentals of joints corrosion and primarily addresses the various forms of corrosion observed in brazed and soldered joints and their causes. It describes the role of proper brazing procedures in controlling corrosion. The article concludes with information on the corrosion resistance of various brazing alloy systems.

This article reviews the corrosion behavior in various environments for seven important nickel alloy families: commercially pure nickel, Ni-Cu, Ni-Mo, Ni-Cr, Ni-Cr-Mo, Ni-Cr-Fe, and Ni-Fe-Cr. It examines the behavior of nickel alloys in corrosive media found in industrial settings. The corrosive media include: hydrochloric acid, sulfuric acid, phosphoric acid, hydrofluoric acid, hydrobromic acid, nitric acid, organic acids, salts, seawater, and alkalis. The modes of high-temperature corrosion include oxidation, carburization, metal dusting, sulfidation, nitridation, corrosion by halogens, and corrosion by molten salts. Applications where the corrosion properties of nickel alloys are important factors in materials selection include the petroleum, chemical, and electrical power industries. Most nickel alloys are much more resistant than the stainless steels to reducing acids, such as hydrochloric, and some are extremely resistant to the chloride-induced phenomena of pitting, crevice attack, and stress-corrosion cracking (to which the stainless steels are susceptible). Nickel alloys are also among the few metallic materials able to cope with hot hydrofluoric acid. The conditions where nickel alloys suffer environmentally assisted cracking are highly specific and therefore avoidable by proper design of the industrial components.

Stainless steels and nickel-base alloys are recognized for their resistance to general corrosion and other categories of corrosion. This article examines the effects of specific alloying elements, metallurgical structure, and mechanical conditioning on corrosion resistance of these materials. It provides information on the compositions of selected stainless steels, copper-nickel, and nickel-base alloys in a tabular form. The article also illustrates the compositional and property linkages for stainless steels and nickel-base alloys.

This article reviews high-temperature corrosion of furnace parts used in heat-treating furnaces. It provides a comparison of cast and wrought materials in the context of their general considerations, advantages, and applications. The article provides information on the heat-resistant alloys used for parts that go through the furnaces, including trays, fixtures, conveyor chains and belts, and quenching fixtures and parts, and the parts that remain in the furnace such as combustion tubes, radiant tubes, burners, thermowells, roller and skid rails, baskets, pots, retorts, muffles, and drive and idler drums. The article also reviews the material characteristics of silicon/silicon carbide composite and reaction-bonded silicon carbide as used in radiant tubes.

The process of making assemblies of solid-solution and precipitation hardening groups of alloys and superalloys often requires welding of dissimilar metals, welding of diffusion-bonded materials, and sometimes weld overlay cladding and even thermal spraying that in turn requires special knowledge and treatments developed specifically for each material. This article emphasizes the special metallurgical welding considerations for welding solid-solution and precipitation hardening nickel alloys, cobalt alloys, and superalloys.

This article tabulates the nominal compositions for nickel and cobalt alloys. It illustrates the comparison of strain-hardening rates of a number of alloys in terms of the increase in hardness with increasing cold reduction. The forming practice for age-hardenable alloys and the lubricants used in the forming processes of nickel and cobalt alloys are also discussed. The article summarizes the modification of tools and dies used for cold forming other metals, as the physical and mechanical properties of nickel and cobalt alloys frequently necessitate it. It discusses forming techniques for these alloys and provides several examples of these techniques, which include shearing, blanking, piercing, deep drawing, spinning, explosive forming, bending, and expanding/tube forming.

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.

The article provides an introduction on the importance of alloying elements on corrosion behavior of nickel alloys and describes the applications of heat-resistant alloys to resist corrosion. It focuses on the metallurgical effects, mainly the effect of internal factors, including chemical composition and microstructure of the alloy, and the external factors, including electrolyte composition, temperature, and electrode potential, on the corrosion behavior of corrosion-resistant alloys. The article also discusses the implication of changing the alloy microstructure by second-phase precipitation, cold working, and cast and wrought forms on the corrosion behavior of high-nickel alloys.

This article provides an overview of the types of postweld heat treatment processes carried out in solid-solution-strengthened and precipitation-strengthened nonferrous high-temperature nickel and cobalt alloys.

This article provides a discussion on forging methods, melting procedures, forging equipment, forging practices, grain refinement, and critical factors considered in forging process. It describes the different types of solid-solution-strengthened and precipitation-strengthened superalloys, namely, iron-nickel superalloys, nickel-base alloys, cobalt-base alloys, and powder alloys. The article discusses the microstructural mechanisms during hot deformation and presents processing maps for various superalloys. It concludes with a discussion on heat treatment of wrought heat-resistant alloy forgings.

Nickel and nickel-base alloys are vitally important to modern industry because of their ability to withstand a wide variety of severe operating conditions involving corrosive environments, high temperatures, high stresses, and combinations of these factors. This article discusses the mining and extraction of nickel and describes the uses of nickel. It discusses the categories of nickel-base alloys, including wrought corrosion-resistant alloys, cast corrosion-resistant alloys, heat-resistant alloys (superalloys), and special-purpose alloys. The article covers the corrosion resistance of nickel with the inclusion of varying alloying elements. It provides useful information on the behavior of nickel and nickel alloys in specific environments describes its corrosion resistance in certain acids, alkalis, and salts.

Submerged arc welding (SAW) is an arc welding process in which the arc is concealed by a blanket of granular and fusible flux. This article provides a schematic illustration of a typical setup for automatic SAW and discusses the advantages and limitations and the process applications of SAW. The article discusses flux classification relative to production method, relative to effect on alloy content of weld deposit, and relative to basicity index. It describes the procedural variations and the effect of weld current, weld voltage, electrical stickout, travel speed, and flux layer depth on weld bead characteristics. The article concludes with information on weld defects, such as lack of fusion, slag entrapment, solidification cracking, hydrogen cracking, or porosity.

The high-temperature corrosion processes that are most frequently responsible for the degradation of furnace accessories are oxidation, carburization, decarburization, sulfidation, molten-salt corrosion, and molten-metal corrosion. This article discusses each corrosion process, along with the corrosion behavior of important engineering alloys. It describes the corrosion of plating, anodizing, and parts of pickling equipment such as tanks, wirings and bus bars, racks, anode splines, pumps, and heaters.

Nickel alloys can be joined reliably by all types of welding processes or methods, with the exception of forge welding and oxyacetylene welding. This article discusses the heat treatment of nickel alloys and tabulates nominal compositions of selected weldable wrought nickel and nickel alloys. It provides information on gas-tungsten arc welding, gas-metal arc welding, plasma arc welding, shielded metal arc welding, and submerged arc welding for welding nickel alloys. The article reviews the defects encountered in the arc welding of nickel alloys, including porosity, cracking, and stress-corrosion cracking. It provides information on the factors that influence the choice of filler metal and welding process of nickel alloys.

Understanding the high-temperature corrosion behavior of alloys is an important step toward the selection of appropriate alloys for process equipment. This article briefly describes the high-temperature corrosion modes that are frequently encountered in the chemical process industry. These modes include oxidation, carburization, metal dusting, nitridation, halogen corrosion, and sulfidation.

This article provides information on nickel alloying elements, and the heat treatment processes of various nickel alloys for applications requiring corrosion resistance and/or high-temperature strength. These processes are homogenization, annealing, solution annealing, solution treating, stabilization treatment, age hardening, stress relieving, and stress equalizing. Discussion of furnaces, fixtures, and atmospheres is included. Nickel alloys used for the heat treatment processes include corrosion-resistant nickel alloys, heat-resistant nickel alloys, nickel-beryllium alloys, special-purpose alloys such as nitinol shape memory alloys, low-expansion alloys, electrical-resistance alloys and soft magnetic alloys. Finally, the article focuses on heat treatment modeling for selecting the appropriate heat treatment process.

This article describes the heat treatment of wrought solid-solution and precipitation-hardening alloys with a focus on the major families of wrought nickel alloys. It also provides information on the heat treatment of some representative solid-solution alloys in the Monel (Ni-Cu), Inconel (Ni-Cr-Mo), Hastelloy (Ni-Mo-Cr), and Incoloy (Ni-Fe-Cr) families of alloys. The heat treatment processes for gamma prime nickel alloys, gamma prime nickel-iron superalloys, and gamma double-prime nickel-iron superalloys are also included. The article also provides information on age-hardenable alloys, and the effects of cold work on aging response and grain growth with examples.

High temperature corrosion may occur in numerous environments and is affected by factors such as temperature, alloy or protective coating composition, time, and gas composition. This article explains a number of potential degradation processes, namely, oxidation, carburization and metal dusting, sulfidation, hot corrosion, chloridation, hydrogen interactions, molten metals, molten salts, and aging reactions including sensitization, stress-corrosion cracking, and corrosion fatigue. It concludes with a discussion on various protective coatings, such as aluminide coatings, overlay coatings, thermal barrier coatings, and ceramic coatings.

Arc welding methods can be classified into shielded metal arc welding, flux-cored arc welding, submerged arc welding, gas metal arc welding, gas tungsten arc welding, plasma arc welding, plasma-metal inert gas (MIG) welding, and electroslag and electrogas welding. This article provides information on process capabilities, principles of operation, power sources, electrodes, shielding gases, flux, process variables, and advantages and disadvantages of these arc welding methods. It presents information about the arc welding procedures of hardenable carbon and alloy steels, cast irons, stainless steels, heat-resistant alloys, aluminum alloys, copper and copper alloys, magnesium alloys, nickel alloys, and titanium and titanium alloys.