AKB - NDT

According to ASNT (American Society for Nondestructive Testing) Nondestructive testing (NDT) has been defined as comprising those test methods used to examine an object, material or system without impairing its future usefulness. The term is generally applied to nonmedical investigations of material integrity.
Strictly speaking, this definition of nondestructive testing does include noninvasive medical diagnostics. Ultrasound, X-rays and endoscopes are used for both medical testing and industrial testing. In the 1940s, many members of the American Society for Nondestructive Testing (then the Society for Industrial Radiography) were medical X-ray professionals. Medical nondestructive testing, however, has come to be treated by a body of learning so separate from industrial nondestructive testing that today most physicians never use the word nondestructive.

A term refering to acoustic vibration frequencies greater than about 18,000 Hertz. Ultrasonic waves have a wide variety of applications over an extended range of intensity, with cutting, cleaning, and the destruction of tissue as one extreme and nondestructive testing (NDT) at the other end.

Testing of welded joints by Ultrasonic equipment is widely used in all over the world. This method is accepted and regulated by international and national standars (ex. EN1714). According to EN norms the thickness of the materials to be examined is to be 8 mm at least but for US norms this value may be decreased to 6 mm. In some special cases by using special techniques and equipments the application limits may vary. In order to make a valid examination according to EN norms the operator and the examinor must have valid EN 473 "level" certificates taken from an recognised organisation. And for US the certificates should be defined by ASNT.

Ultrasonic testing method is very useful and easy way to measure the wall thickness of the vessels, pipelines, boilers and tanks inuse. Someone can determine the corrosion effects by using UT so this makes it possible to find out the safety degree or risc analyse for an equipment.

It is also very common to use UT to find out the flaws or discontinuties in cast materials and forged materials. For most of the critical products like pressure equipments or high speed machine parts, it is required to conduct UT by the regulations.