ultrasonic UT bar inspection flaw detection

Bar or tube production of any type of metal alloy, steel, aluminium brass and also plastics often requires non destructive testing for quality certification.

Ultrasonic bar testing and tube testing is used to inspect the material for the full body and is performed in-line or off-line during or after production.

Depending on the production circumstances and testing speed the bar will be rotated for inspection or the sensors need to rotate around the material when it is not posible to rotate the bar or tube.

For most off- line inspections the bar or tube will be rotated with a number of ultrasonic transducers positioned for proper defect detection such a cracks, inclusions, thickness variations (tube wal thickness) etcetera.

For in-line testing it is often not possible. In this case there are various ways for testing. Phased array is used more often nowadays but multi element around the products is also an effective and high speed method. The highest reliability in combination with testing speed is yet achieved with rotating transducers (https://youtu.be/ukOGpjtQAy8) because these can be sharply focussed for accurate defect detection.

Heavy duty bar inspection

At the right picture you see a large tank for heavy duty bar inspection. Solid bar diameters of up to 400 mm and 5 meter length are 100% tested.

Bars are placed in the tank with a crane after which the ultrasonic inspection is automatically completed. For safety reasons this customer needed complete coverage of the tank during rotation. For this a set of easily sliding covers ( yellow) with safe glass windows can be pulled over the tank.

The MFD900 is placed on a slider to move it to a convenient position

Heavy duty_ultrasonic bar inspection system

Ultrasonic tests with non contact immersion transducers

For ultrasonic testing with non contact immersion transducers it it very important that the transducers remain absolutely perpendicular to the service.

As longer bars are not always absolutely straight a mechanical bar follower system is required which keeps the transdcucers positioned during rotation of the non-traight bar. Obviously there is a limitation in speed for the mechanics to keep track.

Bar followers are made in different concepts. Some only follow in horizontal and vertical position but the best bar followers also have a cardanic mechanism for following the small angles due to the non straightness. Not only for the ultrasonic beam this is of importance but mechanically the motion is much more fluent and it gives less chance for bouncing.
bar follower on titanium bar

Cardanic bar follower on titanium bar designed and built by Inspection Technology Europe Bv.

At the ends of the bar the follower would tilt , but two sensors at both ends of the follower detect the end of bar , activating pneumatic valves to lock the tilt motion so the bar can be inspected till the end.

bar follower on titanium bar

Cardanic bar follower on titanium bar designed and built by Inspection Technology Europe Bv
At the ends of the bar the follower would tilt , but two sensors at both ends of the follower detect the end of bar , activating pneumatic valves to lock the tilt motion so the bar can be inspected till the end.