U - Chemical symbol for Uranium.

U.S.S. Gauge - A gauge system used for carbon steels but not appropriate for stainless steels where thickness is specified in decimals. However, salesperson should always question customer when unsure as to whether U.S.S. or decimal is being specified. For example, 16 gauge for U.S.S. is .058 not .016. U.S.S. does not stand for Ulbrich Stainless Steel.

Ultimate Analysis - In chemistry, this is a quantitive analysis in which percentages of all elements in the substance are determined.

Ultimate Tensile Strength - The highest load applied in breaking a tensile test piece devided by the original cross-sectional area of the test piece.

Ultimate Strength - --The maximum conventional stress, tensile, compressive, or shear, that a material can withstand.

Ultrasonic Cleaning - Immersion cleaning aided by ultrasonic waves which cause microagitation.

Ultrasonic Inspection - A means of locating defects in steel. When acoustic energy in the ultrasonic range is passed through steel, the sound waves tend to travel in straight lines, rather than diffusing in all directions as they do in the audible range. If there is a defect in the path of the beam it will cause a reflection of some of the energy, depleting the energy transmitted. This casts an acoustic shadow which can be monitered by a detector placed opposite the transducer or energy source. If the acoustic energy is introduced as a very short burst, then the reflected energy coming back to the originating transducer can also be used to show the size and depth of the defect. Ultrsonic techniques can be used to detect deeply located defects or those contained in the surface layer. Skill and experience are required in interpreting the results portrayed on the cathode ray tube.

Ultrasonic Testing - A nondestructive test applied to sound-conductive materials having elastic properties for the purpose of locating inhomogeneities or structural discontinuities within a material by means of an ultrasonic beam.

Ultrasonic Waves - Waves of ultrasonic frequency. They include longitudinal, transverse, surface, and standing waves.

Uncover Temperature - The temperature of the coil after processing at the batch anneal - approx. 180 degrees.

Undercooling - See Supercooling

Undercure - (Blocking) If the initial cure is carried out below that necessary for full polymerization undercure may result in subsequent "blocking" or sticking of coated sheets.

Underwind - Steel strip that comes off of the bottom of the coil on the entry reel into the side trimmer.

Underwrap - The direction which coils are being wrapped or unwrapped. If coil is underwrapping the reel is turning and the steel is fed from the bottom.

Unkilled Steel - A wild steel insufficiently deoxidized so that it evolves gas and blowholes during solidification.

UNS - Defines the chemical analysis (Unified Numbering System) as a joint responsibility of the SAE and ASTM.

Upgrading - In castings, the removal and repair of discontinuities to raise the quality level of the casting beyond that which can be economically achieved by good foundry practice.

Upend Forging - A forging in which the metal is so placed in the die that the direction of the fiber structure is at aright angles to the faces of the die.

Upper Yield Point (also Yield Point) - Denoted in yield point phenomenon as a distinct break from the elastic region accompanied by a drop in load, yet prior to plastic deformation in the stress-strain curve in a low-carbon steel.

Upset - Working metal in such a manner that the cross-sectional area of a portion or all of the stock is increased and length is decreased.

Upset Forging - A forging obtained by upset of a suitable length of bar, billet or bloom; formed by heading or gathering the material by pressure upon hot or cold metal between dies operated in a horizontal plane.

Upsetter (Forging Machine) - A machine, with horizontal action, used for making upset forgings.

Upsetting - (1) A metal working operation similar to forging. (2) The process of axial flow under axial compression of metal, as in forming heads on rivets by flattening the end of wire.

Uranium - A white malleable metal which is softer than steel. Its specific gravity is 18.7, it melts at a temperature of 2400oC.

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.

Used Beverage Cans - (UBCs) scrap aluminum beverage cans, although sometimes applied to steel cans as well (steel has a microscopic share of the beverage can market in America but a much larger share in Europe and elsewhere).

Ultimate Strength - The maximum conventional stress, tensile, compressive, or shear, that a material can withstand.

Ultrasonic Frequency - A frequency, associated with elastic waves, that is greater than the highest audible frequency, generally regarded as being higher than 15 kc per sec.

Universal Mill - A rolling mill in which rolls with a vertical axis roll the edges of the metal stock between some of the passes through the horizontal rolls.

Upset - (1) The localized increase in cross-sectional area resulting from the application of pressure during mechanical fabrication or welding. (2) That portion of welding cycle during which the cross-sectional area is increased by the application of pressure.

Utility Sheet Aluminum - Mill finish coiled or flat sheet of unspecified composition and properties produced in specific standard sizes and suitable for general building trade usage.