Search Results for digital solidification analysis

The inspection of castings normally involves checking for shape and dimensions, coupled with aided and unaided visual inspection for external discontinuities and surface quality. This chapter discusses methods for determining surface quality, internal discontinuities, and dimensional inspection. Casting defects including porosity, oxide films, inclusions, hot tears, metal penetration, and surface defects are reviewed. Liquid penetrant inspection, magnetic particle inspection, eddy current inspection, radiographic inspection, ultrasonic inspection, and leak testing for castings are discussed. The chapter provides information on the procedures involved in the inspection of castings that are limited to visual and dimensional inspections, weight testing, and hardness testing. It also discusses the use of computer equipment in foundry inspection operations.

This chapter provides perspective on the physical dimensions associated with the microstructure of steel and the instruments that reveal grain size, morphology, phase distributions, crystal defects, and chemical composition, from which properties and behaviors derive. The chapter also reviews the definitions and classifications used to identify and differentiate commercial steels, including the AISI/SAE and UNS designation systems.

This chapter provides guidelines for conducting metallographic evaluations and offers suggestions on how to effectively report the results. It explains how the approach depends on the objective of the evaluation, which is usually to measure a structural feature, test a hypothesis, or investigate structure-related effects. The chapter addresses each case, tailoring its guidelines and suggestions accordingly.

This chapter gives an overview of how steel castings may be effectively adapted to modern concurrent engineering processes. The chapter discusses computer aided design programs, solid modeling, solidification simulation programs, and rapid prototyping.

This chapter provides an overview of how the disciplines of design, material, and manufacturing contribute to engineering for functional performance. It describes the interaction of product designers and casting engineers in product development. It discusses the consequences of component failure, uncertainty in data and assumptions, and selection of the factor of safety. The chapter also presents an overview of the functional requirements for product performance and provides an overview of product design development. It also presents a partial list of the different tests that are performed on prototypes and examples of product testing. The chapter describes the requirements of a traceability system.

Many of the structural characteristics of steel products are a result of changes that occur during solidification, particularly volume contractions and solute redistribution. This chapter discusses the solidification process and how it affects the quality and behaviors of steel. It explains how steel shrinks as it solidifies, causing issues such as pipe and voids, and how differences in the solubility of solid and liquid steel lead to compositional heterogeneities or segregation. It describes the dendritic nature of solidification, peritectic and eutectic reactions, microporosity, macro- and microsegregation, and hot cracking, as well as the effects of solidification and remelting on castings, ingots, and continuous cast products. It explains how to determine where defects originate in continuous casters and how to control alumina, sulfide, and nitride inclusions.

This chapter discusses the use of electron microscopy in metallographic analysis. It explains how electrons interact with metals and how these interactions can be harnessed to produce two- and three-dimensional images of metal surfaces and generate crystallographic and compositional data as well. It discusses the basic design and operating principles of scanning electron microscopes, transmission electron microscopes, and scanning transmission electron microscopes and how they are typically used. It describes the additional information contained in backscattered electrons and emitted x-rays and the methods used to access it, namely wavelength and energy dispersive spectroscopy and electron backscattering diffraction techniques. It also describes the role of focused ion beam milling in sample preparation and provides information on atom probes, atomic force microscopes, and laser scanning microscopes.

Visual inspection is the most important method of inspection of materials. This chapter describes the procedures involved in visual inspection such as identification markings, identification of defects caused by heating problems, scaling of materials, cracking characterization, and measurement of material dimensions. It discusses the mechanisms, advantages, limitations, components, and applications of various visual inspection tools, namely magnifying devices, lighting for visual inspection, measuring devices, miscellaneous measuring equipment, record-keeping devices, and macroetching.

This chapter discusses the practices and procedures used to reveal and record macrostructural features such as hardening depth, weld thickness, crack size, porosity, hot folds, and machining and tooling marks. It provides information on sectioning, sample location, orientation, surface grinding, and etching. It describes macrographic etchants and the features they reveal along with common etching problems and how to avoid them. It explains how to evaluate etching results and how they can be improved using remedial processes such as light grinding. It also discusses photographic reproduction, lighting, and image enhancement techniques.

This chapter discusses the effects of hot working on the structure and properties of steel. It explains how working steels at high temperatures promotes diffusion, which helps close cavities and pores, and how it changes the shape and distribution of segregates, offsetting their effect. It describes the effect of hot working on nonmetallic inclusions and the many properties influenced by them. It discusses the recrystallization mechanism by which hot working produces microstructural changes and explains how to control it by adjusting temperature, degree of reduction, and cooling rates. It describes special cases of segregation, including banding and why it occurs, and the application of closed die forging. The chapter also presents several examples of hot working defects, including forging laps, cracks, and overheated or burned steel.

This chapter discusses the important role of metallography and the metallographer in predicting and understanding the properties of metals and alloys. Examples are presented of a metallographer working as part of a team in a research laboratory of a large steel company and a metallographer working alone at a small iron foundry. The three basic areas in all metallography laboratories are discussed: the specimen preparation area, the polishing/etching area, and the observation/micrography area. Important safety issues in a metallographic laboratory are also considered.

Weldment failures may be divided into two classes: those identified during inspection and mechanical testing and those discovered in service. Failures in service arise from fracture, wear, corrosion, or deformation. In this article, major attention is directed toward the analysis of service failures. The discussion covers various factors that may lead to the failure of arc welds, electroslag welds, electrogas welds, resistance welds, flash welds, upset butt welds, friction welds, electron beam welds, and laser beam welds.

This chapter gives a brief review of the development of additive manufacturing (AM) and the appeal of different of different AM methods.

This chapter describes some of the most effective tools for investigating boiler tube failures, including scanning electron microscopy, optical emission spectroscopy, atomic absorption spectroscopy, x-ray fluorescence spectroscopy, x-ray diffraction, and x-ray photoelectron spectroscopy. It explains how the tools work and what they reveal. It also covers the topic of image analysis and its application in the measurement of grain size, phase/volume fraction, delta ferrite and retained austenite, inclusion rating, depth of carburization/decarburization, scale thickness, pearlite banding, microhardness, and hardness profiles. The chapter concludes with a brief discussion on the effect of scaling and deposition and how to measure it.

This chapter provides an overview of the various inspection methods used with metals and alloys, namely visual inspection, coordinate measuring machines, machine vision, hardness testing, tensile testing, chemical analysis, metallography, and nondestructive testing. The nondestructive testing methods discussed are liquid penetrant inspection, magnetic particle inspection, eddy current inspection, radiographic inspection, and ultrasonic testing.

This chapter provides information on the properties and behaviors of stainless steels and stainless steel powders. It begins with a review of alloy designation systems and grades by which stainless steels are defined. It then describes the composition, metallurgy, and engineering characteristics of austenitic, ferritic, martensitic, duplex, and precipitation hardening stainless steel powders and metal injection molding grades.

This chapter discusses how aluminum and other alloying constituents are added to prepare a furnace charge for the melting process, and how it is cast into billets of various aluminum alloys. Fundamental aspects of billet casting are covered to give an overview of the casting process. The melting practice is discussed, as well as grain refining and degassing. Charge material, grain refining, degassing, filtration of melt, casting systems, and casting variables are discussed. The chapter concludes with a discussion of casting defects.

This chapter presents several materials and processes related to soldering technology. It first provides information on lead-free solders, followed by sections devoted to flip-chip processes, diffusion soldering, and modeling. Scanning acoustic microscopy and fine-focus x-ray techniques are also discussed. The chapter describes several evaluation procedures and tests developed to measure solderability and standards for process calibration. The chapter also describes the characteristics of reinforced solders, amalgams used as solders, and other strategies to boost the strength of solders. Further, the chapter considers methods for quantifying the mechanical integrity of joints and predicting their dimensional stability under specified environmental conditions. It discusses the effects of rare earth elements on the properties of solders. The chapter concludes with information on advanced joint characterization techniques.

This appendix provides a detailed overview of the crystal structure of metals. It describes primary bonding mechanisms, space lattices and crystal systems, unit cell parameters, slip systems, and crystallographic planes and directions as well as plastic deformation mechanisms, crystalline imperfections, and the formation of surface or planar defects. It also discusses the use of X-ray diffraction for determining crystal structure.