In the field of industrial ultrasonic testing, ultrasonic thickness measurement (UTM) 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) based on the time taken by the ultrasound wave to return to the surface.
Ultrasonic waves have been observed to travel through metals at a constant speed characteristic to a given alloy with minor variations due to other factors like temperature.
is the traverse time The formula features division by two because usually the instrumentation emits and records the ultrasound wave on the same side of the sample using the fact that it is reflected on the boundary of the element.
The measurement does not need to be affected by these since the first recorded return will normally be the head of the emitted wave traveling at the shortest distance which is equivalent to the thickness of the sample.
The ability to gauge thickness measurement without requiring access to both sides of the test piece, offers this technology a multitude of possible applications.
The first ultrasonic thickness gauge was made in 1967 by Werner Sobek;[citation needed] a Polish engineer from Katowice.
Some ultrasonic coating thickness gauges require that a couplant in gel, paste or liquid format be used to eliminate gaps between the transducer and the test piece.
A user friendly interface and saved data and settings allows for the utmost of ease for operators.
NDE technicians equipped with portable UTM probes reach steel plating in sides, tanks, decks and the superstructure.
Contact is usually assured by first removing visible corrosion scale and then applying petroleum jelly or another couplant before pressing the probe against metal.
It is a requirement of many classification societies The techniques and technologies associated with UTM are closely related to the use of ultrasound in other contexts, such as the various other industrial ultrasonic measurements, as well as medical ultrasonography and preclinical imaging micro-ultrasound.
The classification society review the documented procedures of the UTM company and audit them on board in order to issue an approval certificate.