UT (Ultrasonic Testing)
In most common UT applications, very short ultrasonic pulse-waves with center frequencies ranging from 0.1-15 MHz, and occasionally up to 50 MHz, are transmitted into materials to detect internal flaws or to characterize materials. It is used in many industries including steel and aluminium,construction,metallurgy,manufacturing, aerospace, automotive &other transportation sectors. In service ultrasonic testing for preventive maintenance is used for detecting impending failure of rail road rolling stock axles, press columns, earth-moving equipment, mill rolls, mining equipment and other machines and components. The flaws to be detected include voids, cracks, inclusions, pipe, laminations, bursts and flakes. They may be inherent in the raw materials, may result from fabrication and heat treatment, or may occur in service from fatigue, corrosion or other causes. Ultrasonic testing can also be used to measure thickness of metal sections during manufacturing and maintenance inspections.

Ultrasonic Thickness Measurement (UTM)
Confirmation of component thickness can assist in the determination of life expectancy of any part. Ultrasonic Thickness Gages accurately measure wall thickness and corrosion of all metals, including steel and aluminum, plastic, ceramics and others. Thickness gauging is a method of performing non-destructive measurement (gauging) of the local thickness of a solid element (typically made of metal, if using ultrasound testing for industrial purposes) basing on the time taken by the ultrasound wave to return to the surface. This type of measurement is typically performed with an ultrasonic thickness gauge.

UT Applications Include :

Castings
Forgings
Plates
Weld joints
Electrical and electronic component manufacturing
Production of steel
Aluminum
Titanium
Fabrication of structures such as air frames
Pressure vessels
Ships
Bridges
Motor vehicles
Machinery

Following Defects are find out by UT:

CracksLaminationsShrinkageCavitiesBurstsFlakesPoresBonding faults and other discontinuity

UT Advantages :

Does not require access to both sides of the sample
Can be engineered to cope with coatings, linings, etc
Good accuracy (0.1 mm and less) can be achieved using standard timing techniques
Can be easily deployed, does not require laboratory conditions
Digital UTM gives directly Thickness on display
Multi-Mode thickness gauge Machines that has the ability to measure through painted or coated surfaces and eliminate the thickness of the paint using a dual element style transducer in echo-echo mod