Introduction to Nondestructive Testing (NDT)

Nondestructive Testing (NDT) is the method used to examine or inspect a part or material or system without affected future usefulness. Nondestructive Testing (NDT) is utilized to investigate specifically, and it’s concerned in particular way with the performance of the test piece, how long the piece may be utilized and when it is necessary to be checked again. This is the main advantage of Nondestructive Testing (NDT), we can examine without destroying speciment and of course it is saving cost. There are several type of Nondestructive Testing (NDT) type, but commonly used are Magnetic Test(MT), Penetrant Test (PT) , Ultrasonic Test ( UT), and Radiography Test (RT).

Picture : Ultrasonic Testing

Modern Nondestructive Testing (NDT) used by manufacturer for several purposes.

• Ensuring the Integrity/Reliability of a Product

The users of a fabricated product have high expectation that it will give no trouble happen during service for a reason-able period of usefulness. Few of today’s products are expected to deliver decades of service but they are required to give reasonable unfailing value. Public has learned to expect better service and longer life, despite the increasing complexity of our everyday electrical and mechanical appliances.

• Preventing Accidents and Saving Lives

To make sure product reliability is very important because of the general increase in performance expectancy of the public. But reliability merely for convenience and profit is not enough. Reliability to protect human lives is a valuable end it itself. The railroad axle must not fail at high speed. The front spindle of the intercity but must not break on the curve.

• Ensuring Customer Satisfaction

While it is true that the most laudable reason for the use of nondestructive tests is that of safety, it is probably also true that the most common reason is that of making a profit for the user. The sources of this profit are both tangible and intangible.

• Aiding in Product Design

Nondestructive testing aids significantly in better product design. For example, the state of physical soundness as revealed by such nondestructive tests as radiography, magnetic particle or penetrant inspection of a pilot run of castings often shows the designer that design changes are needed to produce a sounder casting in an important section. The design may then be improved and the pattern modified to increase the quality of the product. This example is not academic; it occurs almost daily in many plants.

• Controlling Manufacturing Processes

Almost every nondestructive testing methods is applied in one way or another to assist in process control and so ensure a direct profit for the manufacturer.

• Lowering Manufacturing Costs

Most manufacturers could cut manufacturing costs by deciding where to apply the following cost reduction principle: A nondestructive test can reduce manufacturing cost when it locates undesirable characteristics of a material or component at an early stage, thus eliminating costs of further processing or assembly.

• Maintaining Uniform Quality Level

Once the quality level has been established, production and testing personnel should aim to maintain this level and not to depart from it excessively either toward lower or higher quality. In blunt language, a non destructive test does not improve quality. It can help to establish the quality level but only management sets the quality standard.