undulations per revolution (UPR)
Undulations per revolution, or the number of waves on a workpiece, is a reference to the cutoff frequency of a workpiece.
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Glossary Terms
strain hardening
Increase in hardness and strength caused by plastic deformation at temperatures below the recrystallization range.
stress
Force per unit area, often thought of as force acting through a small area within a plane. It can be divided into components, normal and pa…
stress relieving
Annealing designed to relieve internal stresses caused by machining, welding, casting, cold working, quenching or normalizing.
stress-rupture test, creep-rupture test
Method of evaluating elevated-temperature durability in which a tension-test specimen is stressed under constant load until it breaks. Data…
striation
Fatigue fracture feature, often observed in electron micrographs, that indicates the position of the crack front after each succeeding cycl…
superabrasive tools
Abrasive tools made from diamond or cubic boron nitride, the hardest materials known. See CBN, cubic boron nitride; diamond; PCD, polycryst…
superalloys
Tough, difficult-to-machine alloys; includes Hastelloy, Inconel and Monel. Many are nickel-base metals.
supercooling
Cooling below the temperature at which an equilibrium phase transformation can take place, without actually obtaining the transformation.
superheating
Heating above the temperature at which an equilibrium phase transformation should occur, without actually obtaining the transformation.
superplasticity
Ability of certain metals to undergo unusually large amounts of plastic deformation before local necking occurs.
surface grinding
Machining of a flat, angled or contoured surface by passing a workpiece beneath a grinding wheel in a plane parallel to the grinding wheel …