Ndt Training Institute

K. K. Nagar, Chennai, Tamil Nadu

Ultrasonic gages require access to only one side of pipes, tanks, tubing, containers, hollow castings, large metal or plastic sheets, and other test pieces where the inside surface is impossible or difficult to reach. All common engineering materials can be measured with appropriate gage setups, including metals, plastics, composites, fiberglass, ceramics, and rubber. Most instruments can be pre-programmed with multiple application setups.

Ultrasonic is sound beyond the human audible range that is 20 to 20 kHz. Ultrasonic inspections use frequencies of above 0. 5 MHz up to 25 MHz to test metals, ceramics, glass, composite and other engineering materials. Ultrasonic testing is commonly used for inspecting castings, rolled bars, plates, forgings, thin sheets, extruded components, drawn components, welds and to measure reduction in thickness of pipes, vessels and other components

The test surface is cleaned to remove any dirt, paint, oil, grease or any loose scale that could either keep penetrant out of a defect, or cause irrelevant or false indications. Cleaning methods may include solvents, alkaline cleaning steps, vapor degreasing, or media blasting. The end goal of this step is a clean surface where any defects present are open to the surface, dry, and free of contamination. Note that if media blasting is used, it may "work over" small discontinuities in the part, and an etching bath is recommended as a post-blasting treatment.

Ultrasonic testing is often performed on steel and other metals and alloys, though it can also be used on concrete, wood and composites, albeit with less resolution. It is used in many industries including steel and aluminum construction, metallurgy, manufacturing, aerospace, automotive and other transportation sectors.