Metallurgical Terms
U
U
Chemical symbol for uranium
Ultimate Tensile Stress
(See Tensile Strength)
Ultrasonic Inspection
A method of non-destructive testing which detects internal discontinuities
in metals. Owing to the piezo-electric effect certain crystals can be made to
vibrate when influenced by an oscillating electric current. For ultrasonic
inspection the crystal is made to vibrate at frequencies between 3 and 10
megacycles per second and when held against a piece of steel causes the
vibrations to travel through the steel and be reflected back from the opposite
side or from any intervening defects. The echoes are made visible on a cathode
ray tube.
Unkilled Steel
Steel which has been insufficiently deoxidized and evolves gas during
solidification, with the formation of blow-holes. (See Rising Steel).
Upending
(See Upsetting)
Upsetting
Working a piece of stock in such a way that its length is shortened and its
cross sectional area is increased. It has the effect of increasing ductility in
the radial and tangential directions.