Search Results for laboratory testing method

This article describes the numerous techniques used to measure friction. It provides a brief description of the historical development of friction testing. The article discusses the tests and equipment available for friction testing. It explains the procedural considerations that should be addressed to ensure that valid data are derived from a friction test. The article presents definitions of terms commonly used in tribology such as static friction, kinetic coefficient of friction, stick-slip behavior, and lubricated friction. It provides information on the precautions that must be taken to ensure valid test results. The article also describes how to report data and how to analyze these data.

Galvanic corrosion, although listed as one of the forms of corrosion, is considered as a type of corrosion mechanism that is evaluated by modifying the tests used for conventional forms of corrosion. This article focuses on component testing, computer and physical scale modeling, and laboratory testing methods of evaluating galvanic corrosion. The laboratory tests fall into two categories, namely, electrochemical tests and specimen exposures.

This article provides a perspective on United States (U.S.) Department of Defense (DOD) specifications, standards, handbooks, and related documents, as well as their role in the corrosion prevention and control activities in the U.S. military.

Tribology is the science and technology of interacting surfaces in relative motion or, the study of friction, wear, and lubrication. This article focuses on friction and wear processes that aid in the evaluation and selection of materials, for polymers and some composites used in friction and wear applications. It provides information on friction, types of wear, and lubrication. The article includes a brief description of the friction and wear test methods, laboratory-scale friction, and wear testing, usually performed either to rank the performance of candidate materials for an application or to investigate a particular wear process. It describes the wear tests conducted with/without abrasives and explains the concept of PV limit (where P is contact pressure and V is velocity). The article concludes with references and tables of friction and wear test data for polymeric materials.

This article provides a discussion on probes for laboratory tests and resultant curves of industrial quenching processes. It describes the scope of the tests, and the calculation of heat-transfer coefficient (HTC) based on the tests. The article highlights the differences between the laboratory tests and characterization of industrial quenching processes. It reviews the importance of initial heat-flux density and first critical heat-flux density. The theoretical principle behind and the purpose of the temperature gradient method are discussed. The article provides information on the design of the probe, heat-extraction dynamics, and influence of wetting kinematics. It also includes discussions on the simplified 1-D temperature-distribution model, calculation of the HTC, and the finite-volume method for the heat-conduction equation.

Pitting is a form of localized corrosion that is often a concern in applications involving passivating metals and alloys in aggressive environments. This article describes the test methods for pitting corrosion. These methods include ASTM G 48, ASTM F 746, ASTM G 61, ASTM G 100, and electrochemical noise measurements. The visual examination, metallographic examination, and nondestructive inspection of pits are discussed. The article reviews the procedures for the use of standard charts, metal penetration, statistical analysis, and loss in mechanical properties to quantify the severity of pitting damage.

This article focuses on wet chemical methods that have stood the test of time in laboratories around the world. It begins with a description of the appropriateness of classical wet methods. This is followed by sections on sampling procedures, basic chemical equilibria, and wet analytical chemistry. Mechanical methods and nonoxidizing acids and/or acid mixtures for dissolving solid samples for wet chemical analysis are then reviewed. Qualitative methods that are used to identify materials by wet chemical reaction are also included. The article provides information on various methods for the separation of chemical mixtures and on the types of gravimetry and titrimetry. Strategies for removing inclusions are also included to aid in their compositional understanding. The article also briefly describes the processes involved in chemical surface studies and partitioning of oxidation states. It ends by presenting some examples of the applications of classical wet methods.

This article reviews the fundamentals of electrochemical corrosion test methods. The features and requirements of the instrumentation needed for an electrochemical test are briefly discussed. The article provides a discussion on the various electrochemical techniques and tests available for laboratory studies of corrosion phenomena. The techniques and tests include no-applied-signal tests, small-signal polarization tests, large-signal polarization tests, scanning electrode techniques, and miscellaneous techniques.

Acoustic-emission inspection detects and analyzes minute acoustic-emission signals generated by discontinuities in materials under applied stress. This article discusses the types of acoustic emissions (continuous-type emissions and burst-type emissions) and applications, including laboratory testing, production testing, and structural testing. The article includes a section in which the characteristics of acoustic emission inspection are compared with other nondestructive testing methods. Further, it briefly reviews the key elements of the acoustic-emission instrumentation, which includes the acoustic-emission resonant sensor.

The purpose of accreditation is to evaluate and assure high-quality results from suppliers of products or services without incurring the costs associated with auditing each supplier. This article describes laboratory accreditation based on the general requirements of International Organization for Standardization/International Electrotechnical Commission (ISO/IEC) Guide 25, "General Requirements for the Competence of Calibration and Testing Laboratories." The Guide 25 is a balanced standard that addresses quality system requirements of ISO 9000 and the technical requirements needed to perform testing or calibration. The article describes an accreditation process that would enhance the international acceptance of test data for mechanical testing laboratories.

This article examines the deformation processes in metal-forming operations and considers the effects introduced by scale factors when microforming. It discusses the process parameters and variables affecting surface interactions, including temperature, speed, reduction, stiffness, and dynamic response of equipment. The article reviews the determination of friction coefficient using laboratory monitoring methods, indirect measurements, and the inverse method. It considers the determination of the interface heat-transfer coefficient by using the ring test and computer simulations. The article describes the behavior of oxide scale on the surface of hot metal undergoing thermomechanical processing. It concludes with information on the effects of process and material parameters on interfacial phenomena.

This article presents an approach to characterize the effects of surface treatments to enhance fatigue properties, with particular concern for wear, corrosion, and thermal effects. It discusses the considerations in selecting fabrication or subsequent surface processing procedures to improve fatigue resistance in terms of their respective effects on fatigue performance. The article details the experimental data sets representing specific materials, typical test geometries, and a range of different processing methods used to enhance resistance as compared to results for laboratory tests.

This article briefly reviews the analysis methods for spalling of striking tools with emphasis on field tests conducted by A.H. Burn and on the laboratory tests of H.O. McIntire and G.K. Manning and of J.W. Lodge. It focuses on the metallography and fractography of spalling. The macrostructure and microstructure of spall cavities are described, along with some aspects of the numerous specifications for striking/struck tools. The article also describes the availability of spall-resistant metals and the safety aspects of striking/struck tools in railway applications.

This article provides an overview of cavitation erosion with a specific focus on the estimation of mass loss. It describes the mechanisms of cavitation erosion and the types of laboratory devices to evaluate the resistance to cavitation erosion of materials. The laboratory devices include rotating disks, vibratory devices, cavitating liquid jets, and high-speed cavitation tunnels. The article discusses materials selection and surface protection to prevent cavitation erosion. It reviews the fluid-structure interaction that plays a role in cavitation erosion particularly for compliant materials. The article provides information on the numerical prediction of cavitation erosion damage by the finite element method (FEM).

This article describes the laboratory techniques for direct measurement and quantification of die wear in verifying a proprietary die-wear predictor methodology. This method is based on a theoretical formula that can be used to predict the rate of die wear and the life of a die surface coating, applicable to both mild steel and high-strength steels stampings. The article discusses the behavior of the surface conditions through quantitative measurements and surface analyses conducted throughout the wear tests. The surface conditions include surface roughness, surface morphology, microstructure, interfacial friction, surface temperatures, and wear rate.

This article describes the methods of wear measurements and a model of corrosive wear in mill atmospheres. It explains the polarization curves of pyrrhotite and high-carbon low-alloy steel in a quartzite slurry with examples. The surfaces of pyrrhotite in contact with mild steel or stainless steel affected by galvanic interaction are discussed. The article contains a table that lists the results of laboratory marked ball wear tests for three types of steel balls in wet grinding of magnetic taconite. It also provides information on the mechanism of electrochemical interaction and relative significance of corrosion and abrasion in wear. Galvanic interactions in multielectrode systems are reviewed. The article presents a case history on the material selection for grinding balls to minimize corrosion loss and the adverse effect on flotation.

This article discusses the production process, testing methods, quality control, and common defects found in heavy-section ductile iron (DI) castings, along with analyses of industrial examples. The common defects include shrinkage defects, graphite-particle-related defects, and chunk graphite defects. The recommended chemical compositions for certain section thicknesses in ductile iron grades are presented in a table. The article illustrates the relationship between microstructure and mechanical properties of DI by using either industrial examples or castings produced under laboratory conditions.

Corrosion is the deterioration of a material by a reaction of that material with its environment. The realization that corrosion control can be profitable has been acknowledged repeatedly by industry, typically following costly business interruptions. This article describes the electrochemical nature of corrosion and provides the typical analysis of environmental- and corrosion-related failures. It presents common methods of testing of laboratory corrosion and discusses the processes involved in the prevention of environmental- and corrosion-related failures of metals and nonmetals.

Simulated service testing includes exposures of either structural components or test specimens in environments that are representative of many general service situations. This article discusses the selection criteria of test specimens and methods of assessing the corrosion effects. The ASTM International and NACE International standards that are directly or indirectly applicable to simulated service corrosion testing in water are tabulated. The article also describes the effects of variable concentrations of dissolved carbonates, such as calcium, magnesium, and/or sodium, in water on corrosion.

Independent verification of coating system performance can be based on laboratory testing and/or field exposure. Qualification testing is a critical component to coating system selection. This article focuses on performance evaluations that are used to prequalify coating systems, namely, facility-specific, industry-specific, coating-type-specific, or a combination of these. It describes the standard laboratory tests used to generate performance data, namely, physical, compositional, chemical exposure, and application characteristics tests. The pros and cons of using manufacturer-generated data versus independently generated data are discussed. The article provides information on accelerated corrosion/weathering testing and nuclear level 1/level 2 service coatings qualification. It also describes the procedures for establishing minimum performance requirements and for determining when requalification testing may be required.