Search Results for specialized processing routes

This article presents a detailed account on the process flow, composition, alternative sources, and the advancement of ironmaking, steelmaking and secondary steelmaking practices. Some steels, such as bearing steels, heat-resistant steels, ultrahigh strength missile and aircraft steels, and rotor steels have higher quality requirements and tighter composition control than plain carbon or ordinary low-alloy steels. The production of special-quality steels requires vacuum-based induction or electric remelting and refining capabilities. The article explores the types and characteristics of various steel manufacturing processes, such as ingot casting, continuous casting, and hot rolling. It provides an outline of specialized processing routes of producing ultralow plain carbon steels, interstitial-free steels, high strength low-alloy steels, ultrahigh strength steels, stainless steels, and cold-rolled products, and briefly explains the analytical techniques for liquid steels.

Semisolid metal (SSM) processing, also known as semisolid metal casting, semisolid forming, or semisolid metal forging, is a special die casting process. This article discusses the origin and advantages of the SSM processing. It describes three major semisolid processing routes: thixocasting, rheocasting, and thixomolding.

This article describes the mechanics and processing characteristics of equal-channel angular extrusion (ECAE). Tool design considerations for the ECAE are discussed. During ECAE, severe plastic strains and simple shear deformation mode contribute to strong, sometimes unusual effects of processing on structure and properties. The article explains these effects and concludes with a discussion on the applications of the ECAE.

Semisolid metal (SSM) processing is a special die casting process, where partially solidified metal slurry is injected into a die cavity to form die cast components. This article discusses the flow behavior of an SSM slurry with emphasis on viscosity, rheological behavior, and yield stress. It illustrates the microstructural formation of semisolids under forced convection. The article concludes with an illustration that compares two SSM processes, namely, thixocasting and rheocasting.

Design and analysis of electrical/electronic systems and components tends to be different from the corresponding process for most mechanical and hydraulic systems. This article provides an overview of three overlapping phases followed in electrical design: functional, electrical, and physical. It also presents information on the simulation and testing carried out to evaluate the design behavior.

This article provides a summary of the concepts discussed in the articles under the Section “Post-Processing and Assembly” ASM Handbook, Volume 21: Composites.

This article illustrates various rheocasting processes. These include new rheocasting, semisolid rheocasting, subliquidus casting, rheo-diecasting, swirled enthalpy equilibration device process, slurry-on-demand process, and continuous rheoconversion processes.

The thermomechanical processing (TMP) of conventional and advanced nickel and titanium-base alloys is aimed at altering or enhancing one or more metallurgical features within the material and component. This article presents a number of examples of the TMP of nickel-base superalloys and titanium alloys. The TMP techniques include retained-strain processing, dual-microstructure processing, and dual-alloy processing. The article also describes the TMP of alpha-beta titanium alloys, including fine-grain processing, hybrid-structure processing, dual-microstructure processing, and dual-alloy processing. It concludes with a discussion on computer simulation of advanced TMP processes.

This article commences with a discussion on the qualitative and quantitative criteria for metal injection molding (MIM), including production quantities, shape complexity, material performance, and cost. It discusses geometric factors, such as surface finish, component size, and mass range, which help to identify a component for MIM. The article describes certain part features, including holes, undercuts, and flat faces. It concludes with a discussion on the common materials used in MIM; tensile properties of 17-4 PH stainless steel MIM, cast and wrought products; and attributes of the MIM process.

This article discusses three types of powder-feeder systems that are commonly used throughout the thermal spray (TS) industry: gravity-based devices, rotating wheel devices, and fluidized-bed systems. It provides information on the various mechanical methods for producing powders, namely, crushing, milling, attriting, and machining. The article describes two prime methods of agglomeration. One method uses a binder by way of agglutination, while the other relies on a sintering operation. The article discusses the technology and principles of the processes that relate to thermal spraying, and offers an understanding for choosing particular feedstock materials that are classified based on the thermal spray process, material morphology, chemical nature of the material, and applications. Sieving, the most common method of separating powders into their size fractions, is also reviewed. The article also provides information on the topical areas and precautions to be undertaken to protect the operator from safety hazards.

This article describes the basic functions that should be included when considering the relationship of computer-aided design (CAD)/computer-aided manufacturing (CAM) and machining. These include design, analysis, drafting, process planning, part programming, program verification, part machining, and inspection. The article provides information on hardware, data base, interfaces, and benefits of integrating machining with the CAD/CAM system of a manufacturing plant. It also provides an overview of direct, computer and, distributed numerical control, which are devoid of a number of problems inherent in conventional numerical control.

This article focuses on the forging characteristics of different types of refractory metals and alloys, namely, niobium and niobium alloys, molybdenum and molybdenum alloys, tantalum and tantalum alloys, and tungsten and tungsten alloys.

Honeycomb is a product consisting of very thin sheets attached to form connecting cells. This article briefly explains the construction, core characteristics, properties, and testing methods of the honeycomb structures. It discusses the special processes carried out in customizing the shape of core to fit customer's specific needs. The article provides information on the basic concept of creating sandwich structures and its corresponding aspects like material selection, design guidelines, and structural efficiency.

This article describes the process of materials selection in relation to the design process, such as materials selection for a new design and materials substitution for an existing design. It reviews the performance characteristics of materials using prototype tests or field tests to determine their performance under actual service conditions. The article describes the selection of a material in relation to the manufacturing process and presents the factors that influence materials selection based on costs and related aspects. These factors include metallurgical requirements, dimensions, processing, quantity, packing, marking, and loading. The article discusses how the needs for materials data evolve as a design proceeds from conceptual to detail design. It describes the methods of materials selection, namely, cost per unit property method, weighted property index method, and limits on properties method.

This article reviews various segments of the powder metallurgy (PM) process from powder production and powder processing through the characterization of the materials and their properties. It covers the processing methods for consolidating metal powders including options for processing to full density. The article outlines the freeform fabrication process, also known as additive manufacturing and describes finishing operations of PM parts. It concludes with information on the applications of PM parts.

This article explores the possibilities and limitations imposed by manufacturing processes and materials. Detailed design rules for the processes are presented. The article lists the main features of process groups in a tabular form. The physical characteristics and ratings of relative cost and production factors are also tabulated. The process groups include casting; deformation; powder processing; machining; noncutting; joining; ceramic, glass, and polymer processing; and composites manufacturing.

Documentation must be focused toward explaining a specific task such as design process, by conveying the needs of product engineering, materials engineering, and manufacturing. This article describes how documentation supports the process of bringing a product to market, who uses the information, and how it serves as a key form of communication, with examples. It discusses the key features that most documents must define. The article describes the requirements of engineering and manufacturing and how drawings are used as a communication medium.

This article describes the coating materials, surface-preparation requirements, and application techniques used to protect underground pipelines. It provides a valuable insight into the types of polymer-based coatings that are both cost-effective and widely accepted in the pipeline industry.

Spray casting, also known as spray forming, is a niche casting process for the manufacture of preforms. This article lists commercial examples of alloys manufactured by spray casting and provides sequential steps of the spray casting process. Gas atomization is a chaotic, stochastic process that always produces a wide range of droplet diameters. The article schematically illustrates a typical log-normal droplet diameter probability density distribution on a mass or volume basis obtained by gas atomization. It also explains the changes in solid fraction during the spray casting process as a function of axial distance from the point of droplet atomization. The article concludes with information on the occurrence of macrosegregation and coarsening in spray cast preforms.

Hot-rolled steel bars and other hot-rolled steel shapes are produced from ingots, blooms, or billets converted from ingots or from strand cast blooms or billets and comprise a variety of sizes and cross sections. Most carbon steel and alloy steel hot-rolled bars and shapes contain surface imperfections with varying degrees of severity. Seams, laps, and slivers are probably the most common defects in hot-rolled bars and shapes. Another condition that could be considered a surface defect is decarburization. Hot-rolled steel bars and shapes can be produced to chemical composition ranges or limits, mechanical property requirements, or both. Hot-rolled carbon steel bars are produced to two primary quality levels: merchant quality and special quality. Merchant quality is the least restrictive descriptor for hot-rolled carbon steel bars. Special quality bars are employed when end use, method of fabrication, or subsequent processing treatment requires characteristics not available in merchant quality bars.