Search Results for cone angle

A newly developed theory on plasticity makes it possible to include elastic effects, which play a major role when using blunt hardness indenters. This article reviews the new theory and explains several phenomena associated with practical hardness testing. In the indentation hardness test, a blunt indenter that approximates a flat punch is forced into a plane surface. The effective cone angle for most indenters is such that some upward flow results even when there is sufficient material surrounding the indenter to provide a full elastic constraint. When loaded by a blunt indenter, materials with high values of Young's Modulus of Elasticity/uniaxial flow stress (E/Y) (metals) appear to develop a Hertzian stress distribution over the contact. In contrast, materials with low values of E/Y (glasses and polymers) develop a uniform distribution of stress.

This article provides an overview of the relationships between torque, angle-of-turn, tension, and friction and explains how they are measured and evaluated. It focuses on the principle, test equipment, procedure, evaluation, and test report of various testing methods, namely, friction coefficient testing, torque tension testing, locknut testing, and angular ductility and rotational capacity tests. The article reviews the basic methods and fundamental principles for mechanical testing of externally and internally threaded fasteners and bolted joints. The test methods for externally threaded fasteners include product hardness, proof load, axial and wedge tension testing of full-sized products, tension testing of machined test specimens, and total extension at fracture testing. Product hardness, proof load, and cone proof-load test are the test methods for internally threaded fasteners. The article concludes with a description of torque-angle signature analysis and the specification of measurement accuracy for torque and clamp force.

Metal spinning is a term used to describe the forming of metal into seamless, axisymmetric shapes by a combination of rotational motion and force. This article describes two forming techniques, such as manual spinning and power spinning, for forming seamless metal components. The process technology, equipment, and tooling for both manual spinning and power spinning are also discussed.

This article is an atlas of fractographs that helps in understanding the causes and mechanisms of fracture of medium-carbon steels and in identifying and interpreting the morphology of fracture surfaces. The fractographs illustrate the torsional-fatigue fracture, cup and cone tensile fracture, brittle fracture, and in-service rotary bending fatigue fracture of fractured roof-truss angles, pressure-vessel shells, automotive axle shafts, broken keyed spindles, crane gears, blooming-mill spindles, automotive bolts, and crane wheels of these steels.

This article is a brief account of low-energy ion-scattering spectroscopy (LEIS) for determining the atomic structure of solid surfaces. It begins with a description of the general principles of LEIS. This is followed by a section providing information on the equipment used for LEIS. Various steps involved in the sample preparation, calibration, and data analysis are then discussed. The article concludes with a section on the applications and interpretation of LEIS in material analysis, including discussion on surface structural analysis, layer-by-layer (Frank-van der Merwe) growth, and low-energy atom-scattering spectroscopy.

Spray quenching (or jet impingement) is the most common technique employed to improve the uniformity of heat removal and break the vapor layer, allowing for a high cooling rate to be achieved. This article presents the heat transfer characteristics of quenching a hot surface, which can be expressed by the boiling and quench curve. It discusses three major spray parameters that have a substantial role in the quantification of spray cooling performance: droplet size, droplet velocity, and volumetric flux. The article also presents the available models and correlations to predict the cooling rate in spray quenching of hot surfaces during different boiling phases. It then discusses the effect of surface roughness on spray cooling performance.

X-ray diffraction techniques are useful for characterizing crystalline materials, such as metals, intermetallics, ceramics, minerals, polymers, plastics, and other inorganic or organic compounds. This article discusses the theory of x-rays and how they are generated and detected. It also describes the crystalline nature of certain materials and how the geometry of a unit cell, and hence crystal lattice, affects the direction and intensity of diffracted x-ray beams. The article concludes with several application examples involving measurements on single and polycrystalline materials.

This article describes the methods of X-ray diffraction analysis, the types of information that can be obtained, and its interpretation. The discussion covers the basic theories of X-rays and various types of diffraction experiments, namely single-crystal methods for polychromatic and monochromatic beams, powder diffraction methods, and the Rietveld method.

This article discusses the mill products most often formed by the three-roll forming process. It schematically illustrates some of the shapes commonly produced from flat stock by the three-roll forming process. The article describes the two basic types of three-roll forming machines, namely, the pinch-roll type and the pyramid-roll type. It also lists the advantages of the pinch-roll machine, as compared to the pyramid-roll machine. The article analyzes the hot forming and cold forming processes for carbon or low alloy steel. It explains the procedure for forming truncated cones, bars, and bar sections by utilizing the pyramid-roll machine.

This article provides a practical reference guide for instrumented indentation testing (IIT). It summarizes the various types of indenters used in IIT and parameters describing their geometries. The article discusses the physical principles and models used to determine hardness and elastic modulus from indentation load displacement data. Indentation deformation can be time-dependent, with the extent and nature of the time dependence strongly influenced by temperature. The article examines the methods for probing and characterizing the time-dependent phenomena. It also emphasizes the better-developed measurement techniques and procedures and calibrations required to obtain accurate and meaningful measurements.

This article describes the methods for determining the flow rate of metal powders. It examines the factors affecting flow rate, apparent density, and angle of repose of metal powders. The article reviews the frictional properties, cohesive strength, frictional properties, tap density, and compressibility of metal powders. It explains the mechanisms of powder segregation. The article provides information on green strength and springback value of rectangular test bar. It concludes with a discussion on the chemical composition of metal powders.

Oxyfuel gas welding (OFW) is a manual process in which the metal surfaces to be joined are melted progressively by heat from a gas flame, with or without a filler metal. This article discusses the capabilities, advantages, and limitations of OFW. It describes the role of gases, such as oxygen, acetylene, hydrogen, natural gas, propane, and proprietary gases, in OFW. The article discusses the important elements of an OFW system, such as gas storage facilities, pressure regulators, hoses, torches, related safety devices, and accessories. It describes the sequence for setting up a positive-pressure welding outfit. The article provides information on forehand welding and backhand welding, as well as various joints used. It concludes with a discussion on repairs and alterations, as well as the safety aspects.