Ultimate Tensile Strength (uts): The maximum tensile stress a metal can stand. See Tensile Strength.
Ultrasonic Cleaning: Immersion cleaning aided by ultrasonic waves which cause microagitation.
Ultrasonic Testing: A nondestructive method of testing metal for flaws based on the fact that ultrasonic waves are reflected and refracted at the boundaries of a solid medium.
Unkilled Steel: A wild steel insufficiently deoxidized so that it evolves gas and blowholes during solidification.
Urea Formaldehyde Resin: A thermosetting product of condensation from urea or thio-urea and formaldehyde, soluble in water and used as a sand binder in core and mold compounds.